阅读说明：本技术 电磁辐射转向机构 (Electromagnetic radiation steering mechanism ) 是由 P.J.屈肯达尔 于 2018-11-22 设计创作，主要内容包括：一种电磁辐射转向机构。一种被构造成使电磁辐射转向以寻址二维视场内的特定位置的电磁辐射转向机构,其包括：具有相关联的第一致动器的第一光学元件,所述第一致动器被构造成使所述第一光学元件围绕第一旋转轴线旋转以改变所述二维视场中第一转向轴线的第一坐标；具有相关联的第二致动器的第二光学元件,所述第二致动器被构造成使所述第二光学元件围绕第二旋转轴线旋转以改变所述二维视场中第二转向轴线的第二坐标；以及电磁辐射操纵器,所述电磁辐射操纵器以光学方式设置在所述第一光学元件与第二光学元件之间。第一角度限定在所述第一旋转轴线与第二旋转轴线之间,并且第二角度限定在所述第一转向轴线与第二转向轴线之间。所述电磁辐射操纵器被构造成在所述第一角度与所述第二角度之间引入差。(An electromagnetic radiation steering mechanism. An electromagnetic radiation steering mechanism configured to steer electromagnetic radiation to address a particular location within a two-dimensional field of view, comprising: a first optical element having an associated first actuator configured to rotate the first optical element about a first axis of rotation to change a first coordinate of a first steering axis in the two-dimensional field of view; a second optical element having an associated second actuator configured to rotate the second optical element about a second axis of rotation to change a second coordinate of a second steering axis in the two-dimensional field of view; and an electromagnetic radiation manipulator optically disposed between the first and second optical elements. A first angle is defined between the first and second axes of rotation and a second angle is defined between the first and second steering axes. The electromagnetic radiation manipulator is configured to introduce a difference between the first angle and the second angle.)

1. An electromagnetic radiation steering mechanism configured to steer electromagnetic radiation to address a particular location within a two-dimensional field of view, comprising:

a first optical element having an associated first actuator configured to rotate the first optical element about a first axis of rotation to change a first coordinate of a first steering axis in the two-dimensional field of view;

a second optical element having an associated second actuator configured to rotate the second optical element about a second axis of rotation to change a second coordinate of a second steering axis in the two-dimensional field of view; and

an electromagnetic radiation manipulator optically disposed between the first optical element and the second optical element, wherein,

a first angle is defined between the first and second axes of rotation;

a second angle is defined between the first and second steering axes; and the number of the first and second electrodes,

the electromagnetic radiation manipulator is configured to introduce a difference between the first angle and the second angle.

2. The electromagnetic radiation steering mechanism of claim 1, wherein the first axis of rotation and the second axis of rotation are non-orthogonal.

3. The electromagnetic radiation steering mechanism of claim 1 or claim 2, wherein the first axis of rotation and the second axis of rotation are substantially parallel.

4. The electromagnetic radiation steering mechanism of any of claims 1-3, wherein the first angle is less than about 45 °, and optionally wherein the first angle is less than about 10 °, and optionally wherein the first angle is less than about 5 °, and optionally wherein the first angle is less than about 2 °, and optionally wherein the first angle is about 0 °.

5. The electromagnetic radiation steering mechanism of any one of claims 1-4, wherein the first steering axis and the second steering axis are substantially orthogonal.

6. The electromagnetic radiation steering mechanism of any one of claims 1 to 4, wherein the second angle is between about 70 ° and about 110 °, and optionally wherein the second angle is between about 80 ° and about 100 °, and optionally wherein the second angle is between about 85 ° and about 95 °, and optionally wherein the second angle is about 90 °.

7. The electromagnetic radiation steering mechanism of any one of claims 1 to 6, wherein the electromagnetic radiation manipulator is configured to introduce a difference of greater than about 45 ° between the first angle and the second angle, and optionally wherein the electromagnetic radiation manipulator is configured to introduce a difference of greater than about 70 ° between the first angle and the second angle, and optionally wherein the electromagnetic radiation manipulator is configured to introduce a difference of about 90 ° between the first angle and the second angle.

8. The electromagnetic radiation steering mechanism of any of claims 1-7, wherein the first optical element is adjacent to the second optical element.

9. The electromagnetic radiation steering mechanism of any of claims 1-8, wherein the first optical element is configured to receive the electromagnetic radiation and direct the electromagnetic radiation to the electromagnetic radiation manipulator, and wherein the electromagnetic radiation manipulator is configured to direct the electromagnetic radiation to the second optical element.

10. The electromagnetic radiation steering mechanism of claim 9, wherein the second optical element is configured to direct the electromagnetic radiation to an optical output of the electromagnetic radiation steering mechanism.

11. The electromagnetic radiation steering mechanism of claim 9, wherein the second optical element is configured to direct the electromagnetic radiation to an optical input of an optical device configured to receive the steered electromagnetic radiation.

12. The electromagnetic radiation steering mechanism of any of claims 1-11, wherein at least one of the first optical element and the second optical element is reflective.

13. The electromagnetic radiation steering mechanism of claim 12, wherein the first optical element includes a first reflective surface configured to receive the electromagnetic radiation, and wherein the second optical element includes a second reflective surface configured to receive the electromagnetic radiation.

14. The electromagnetic radiation steering mechanism of claim 13, wherein the first axis of rotation and the first reflective surface are substantially parallel.

15. The electromagnetic radiation steering mechanism of claim 13 or claim 14, wherein the second axis of rotation and the second reflective surface are substantially parallel.

16. The electromagnetic radiation steering mechanism of any of claims 1-11, wherein at least one of the first optical element and the second optical element is refractive.

17. The electromagnetic radiation turning mechanism of claim 16, wherein the refractive optical element is a prism.

18. The electromagnetic radiation steering mechanism of any of claims 1-17, wherein at least one of the first and second optical elements is diffractive.

19. The electromagnetic radiation steering mechanism of claim 18, wherein the diffractive optical element comprises a grating.

20. An electromagnetic radiation steering mechanism according to any one of claims 1 to 19, wherein at least one of the first and second optical elements is polarizing.

21. The electromagnetic radiation steering mechanism of claim 20, wherein the polarizing optical element is configured to change linearly polarized electromagnetic radiation to circularly polarized electromagnetic radiation.

22. The electromagnetic radiation steering mechanism of any one of claims 1-21, wherein the electromagnetic radiation manipulator comprises a first mirror and a second mirror.

23. The electromagnetic radiation steering mechanism of claim 22, wherein the first mirror is configured to receive the electromagnetic radiation after the electromagnetic radiation has interacted with the first optical element and direct the electromagnetic radiation to the second mirror.

24. The electromagnetic radiation steering mechanism of claim 23, wherein the second mirror is configured to receive the electromagnetic radiation after the electromagnetic radiation has interacted with the first mirror and direct the electromagnetic radiation to the second optical element.

25. The electromagnetic radiation turning mechanism of any of claims 22-24, wherein the first mirror and the second mirror are fixed relative to each other.

26. The electromagnetic radiation steering mechanism of claim 25, wherein the first mirror is arranged to impart an approximately 90 ° change in the direction of the electromagnetic radiation.

27. The electromagnetic radiation turning mechanism of claim 25 or claim 26, wherein the second mirror is arranged to impose an approximately 90 ° change in the direction of the electromagnetic radiation.

28. The electromagnetic radiation steering mechanism of claim 26 and claim 27, wherein the 90 ° change in direction of the electromagnetic radiation caused by the first mirror occurs about a first reflection axis and the 90 ° change in direction of the electromagnetic radiation caused by the second mirror occurs about a second reflection axis, wherein the first and second reflection axes are non-parallel.

29. The electromagnetic radiation steering mechanism of claim 28, wherein the first reflective axis and the second reflective axis are substantially perpendicular.

30. The electromagnetic radiation steering mechanism of any one of claims 1-29, wherein at least one of the first and second actuators comprises a galvanometer motor.

31. The electromagnetic radiation steering mechanism of any one of claims 1-30, wherein the electromagnetic radiation is a laser beam.

32. A laser marking system for marking a product comprising a marking head and an electromagnetic radiation steering mechanism according to any one of claims 1 to 31.

33. The laser marking system as claimed in claim 32, wherein the first and second axes of rotation are substantially parallel, and wherein the electromagnetic radiation steering mechanism is mounted substantially parallel to the marking head of the laser marking system such that a length of the marking head is substantially parallel to the first and second axes of rotation.

34. The laser marking system according to claim 33, wherein the marking head comprises a cylindrical housing.

35. The laser marking system according to any one of claims 32 to 34, further comprising a flexible umbilical connected to the marking head and configured to transmit power and/or control signals to the marking head.

36. Laser marking system according to any one of claims 32 to 35, wherein the marking head comprises a radiation shield for protecting a user of the laser marking system from stray radiation.

37. The laser marking system according to claim 36, wherein the radiation shield includes a sensor configured to detect radiation emitted from a gap between a portion of the radiation shield and the product.

38. Laser marking system according to claim 36 or claim 37, wherein the radiation shield comprises an integrated extraction inlet fluidically coupled to an extraction device configured to generate a flow of extraction fluid for extracting a substance resulting from an interaction between the laser beam and the product.

39. The laser marking system according to claim 38, wherein the integrated extraction inlet is configurable to be positioned substantially adjacent to the product.

40. Laser marking system according to any one of claims 36 to 39, wherein the radiation shield comprises a flange for providing further protection from stray radiation to a user of the laser marking system.

41. Laser marking system according to any one of claims 36 to 40, wherein the radiation shield comprises a flexible member arranged to reduce a gap between the radiation shield and the product for providing further protection from stray radiation to a user of the laser marking system.

42. An electromagnetic radiation detector comprising an electromagnetic radiation steering mechanism according to any one of claims 1 to 31.

43. The electromagnetic radiation detector of claim 42, wherein the first axis of rotation and the second axis of rotation are substantially parallel, and wherein the electromagnetic radiation steering mechanism is mounted substantially parallel to the electromagnetic radiation detector such that a length of the electromagnetic radiation detector is substantially parallel to the first axis of rotation and the second axis of rotation.

44. An optical scanner comprising an electromagnetic radiation steering mechanism as claimed in any one of claims 1 to 31.

45. The optical scanner of claim 44 wherein the first and second axes of rotation are substantially parallel, and wherein the electromagnetic radiation steering mechanism is mounted substantially parallel to the optical scanner such that a length of the optical scanner is substantially parallel to the first and second axes of rotation.

46. An optical scanner according to claim 44 or claim 45 wherein the optical scanner comprises a laser source configured to generate and direct the electromagnetic radiation in a direction parallel to the first and second axes of rotation.

47. A method of steering electromagnetic radiation to address a particular location within a two-dimensional field of view, comprising:

receiving electromagnetic radiation at a first optical element rotatable about a first axis of rotation to change a first coordinate of a first steering axis in the two-dimensional field of view;

directing the electromagnetic radiation to an electromagnetic radiation manipulator optically disposed between the first optical element and the second optical element;

directing the electromagnetic radiation to the second optical element, the second optical element being rotatable about a second axis of rotation to change a second coordinate of a second steering axis in the two-dimensional field of view;

defining a first angle between the first and second axes of rotation;

defining a second angle between the first and second steering axes; and the number of the first and second groups,

using the electromagnetic radiation manipulator to introduce a difference between the first angle and the second angle.

48. A method of marking a product using an electromagnetic radiation steering mechanism, comprising:

receiving electromagnetic radiation at a first optical element rotatable about a first axis of rotation to change a first coordinate of a first steering axis in the two-dimensional field of view;

directing the electromagnetic radiation to an electromagnetic radiation manipulator optically disposed between the first optical element and the second optical element;

directing the electromagnetic radiation to the second optical element, the second optical element being rotatable about a second axis of rotation to change a second coordinate of a second steering axis in the two-dimensional field of view;

defining a first angle between the first and second axes of rotation;

defining a second angle between the first and second steering axes;

using the electromagnetic radiation manipulator to introduce a difference between the first angle and the second angle; and the number of the first and second groups,

the electromagnetic radiation is diverted around the product by rotating the first and second optical elements.

49. The method of claim 48, wherein the electromagnetic radiation steering mechanism is located within a marking head of a laser marking system, the method further comprising: moving the marking head during the marking.

50. A method of detecting electromagnetic radiation, comprising:

receiving electromagnetic radiation at a first optical element rotatable about a first axis of rotation to change a first coordinate of a first steering axis in the two-dimensional field of view;

directing the electromagnetic radiation to an electromagnetic radiation manipulator optically disposed between the first optical element and the second optical element;

directing the electromagnetic radiation to the second optical element, the second optical element being rotatable about a second axis of rotation to change a second coordinate of a second steering axis in the two-dimensional field of view;

defining a first angle between the first and second axes of rotation;

defining a second angle between the first and second steering axes; and the number of the first and second groups,

using the electromagnetic radiation manipulator to introduce a difference between the first angle and the second angle.

51. The method of claim 50, wherein the method further comprises: imaging an object using the electromagnetic radiation.

52. A method of assembling an electromagnetic radiation steering mechanism, comprising:

mounting a first optical element and an associated first actuator, the first actuator configured to rotate the first optical element about a first axis of rotation to change a first coordinate of a first steering axis in a two-dimensional field of view;

mounting a second optical element having an associated second actuator configured to rotate the second optical element about a second axis of rotation to change a second coordinate of a second steering axis in the two-dimensional field of view; and

an electromagnetic radiation manipulator is optically disposed between the first optical element and the second optical element.

53. A method of retrofitting a production system including a continuous inkjet marking system, comprising:

replacing the continuous inkjet marking system with the laser marking system according to any one of claims 32 to 41.

54. Laser marking system according to any one of claims 32 to 41, further comprising a variable optical path length assembly configured to define an optical path from an input to an output.

Technical Field

The invention relates to an electromagnetic radiation steering mechanism. Aspects and embodiments of the present disclosure generally relate to laser scanning and laser marking equipment.

Background

Current laser marking machines and scanners are limited during packaging and automated production operations in part marking lines. Current laser markers and scanners are typically fixed into the production system relative to the article being marked.

A known electromagnetic radiation steering mechanism comprises two mirrors. The first mirror is configured to rotate about a first axis of rotation to steer the electromagnetic radiation along a first steering axis, and the second mirror is configured to rotate about a second axis of rotation to steer the electromagnetic radiation along a second steering axis. The first steering axis and the second steering axis are perpendicular such that the electromagnetic radiation may be steered around the two-dimensional field of view. In order to achieve perpendicular first and second steering axes, it is known to orient the first and second axes of rotation of the first and second mirrors in the electromagnetic radiation steering mechanism orthogonally with respect to each other. Thus, in known electromagnetic radiation steering mechanisms, the axis of rotation and the steering axis may be described as being directly coupled. That is, in order for the first and second steering axes to be orthogonal, the first and second axes of rotation of the mirror must also be orthogonal. This typically results in a large, bulky and cumbersome electromagnetic radiation steering mechanism, since the housing of the electromagnetic radiation steering mechanism must be large enough to accommodate the orthogonally oriented steering mirror and its associated actuators.

It is an object of the present invention to provide an electromagnetic radiation steering mechanism that obviates or mitigates one or more of the problems of the prior art, as noted herein or elsewhere.

Disclosure of Invention

Aspects and embodiments disclosed herein enable easy integration and operation of an optical scanning or marking system (e.g., a laser scanning or marking system) into a production system. Aspects and embodiments disclosed herein include an optical scanning system that can be inserted coaxially (i.e., substantially parallel) with a laser beam of a laser scanning or marking system. The compact size of the resulting scanning/marking head facilitates the integration of laser scanning or marking equipment into a production line.

According to a first aspect of the present invention there is provided an electromagnetic radiation steering mechanism configured to steer electromagnetic radiation to address a particular location within a two-dimensional field of view, comprising: a first optical element having an associated first actuator configured to rotate the first optical element about a first axis of rotation to change a first coordinate of a first steering axis in the two-dimensional field of view; a second optical element having an associated second actuator configured to rotate the second optical element about a second axis of rotation to change a second coordinate of a second steering axis in the two-dimensional field of view; and an electromagnetic radiation manipulator optically disposed between the first and second optical elements, wherein a first angle is defined between the first and second axes of rotation, a second angle is defined between the first and second steering axes, and the electromagnetic radiation manipulator is configured to introduce a difference between the first and second angles.

The electromagnetic radiation manipulator may be referred to as an electromagnetic radiation spatial distribution transformer. That is, the electromagnetic radiation manipulator may be configured to manipulate the electromagnetic radiation by transforming the incident electromagnetic radiation from a first propagation direction and/or orientation to a different propagation direction and/or orientation. The electromagnetic radiation manipulator may be referred to as an electromagnetic radiation spatial distribution rotator. That is, the electromagnetic radiation manipulator may be configured to manipulate the electromagnetic radiation by rotating the direction of propagation and/or orientation of the incident electromagnetic radiation. The electromagnetic radiation manipulator may be regarded as a stationary assembly in contrast to the rotatable first and second optical elements.

Each of the first optical element and the second optical element may be referred to as a deflector or a variable deflector. That is, the first optical element and the second optical element may be configured to variably deflect incident electromagnetic radiation such that, as the first optical element and/or the second optical element rotates, electromagnetic radiation exiting the electromagnetic radiation steering mechanism is steered around the two-dimensional field of view. Rotation of the first optical element or the second optical element may change the deflection of the electromagnetic radiation caused by the first optical element and/or the second optical element.

Each of the first steering axis and the second steering axis may be referred to as a yaw axis or a yaw degree of freedom. This is because each optical element may be configured to deflect electromagnetic radiation and thereby change the direction of propagation and/or orientation of the electromagnetic radiation. The two degrees of freedom of deflection associated with the first optical element and the second optical element may be combined to address a particular location within the two-dimensional field of view around which electromagnetic radiation may be steered.

The two-dimensional field of view may correspond to an imaginary plane at a fixed distance from the electromagnetic radiation steering mechanism onto which the electromagnetic radiation is projected. For example, the two-dimensional field of view may be substantially coplanar with a portion of a surface of a product to be marked using electromagnetic radiation.

The two-dimensional field of view may, for example, have dimensions of about 60 mm by about 80 mm. The two-dimensional field of view may, for example, have dimensions of about 200mm by about 300 mm. The size of the two-dimensional field of view may depend at least in part on the distance between the output of the electromagnetic radiation steering mechanism and the surface on which the electromagnetic radiation is steered. If an electromagnetic radiation steering mechanism is used as part of the marking head of the laser marking system, the distance between the output of the marking head and the product to be marked may be between about 100 mm and about 500 mm, for example about 300 mm.

Each of the first actuator and the second actuator may be referred to as a drive mechanism. That is, the first actuator is configured to drive rotation of the first optical element about the first axis of rotation, and the second actuator is configured to drive rotation of the second optical element about the second axis of rotation.

The first angle may be zero. That is, the first axis of rotation and the second axis of rotation may be substantially parallel. Alternatively, the first angle may be non-zero. That is, the first axis of rotation and the second axis of rotation may not be parallel.

For a given point in the two-dimensional field of view, rotating the first optical element will cause the position of the electromagnetic radiation to change along the first steering axis, and rotating the second optical element will cause the position of the electromagnetic radiation to change along the second steering axis. There may be a degree of linear independence between the first and second steering axes. For example, the second angle may be less than 90 ° (e.g., about 80 °), and the electromagnetic radiation steering mechanism may still effectively address multiple locations within the two-dimensional field of view around which electromagnetic radiation may be steered. The first steering axis and/or the second steering axis may not be linear. For example, the first steering axis and/or the second steering axis may be curvilinear.

Each steering axis may be described using any desired coordinate system, such as a cartesian coordinate system, a spherical polar coordinate system, a cylindrical polar coordinate system, and so forth. For example, when describing the steering axis using cartesian coordinates, the "x" coordinate may be considered a first coordinate of the first steering axis and the "y" coordinate may be considered a second coordinate of the second steering axis. Alternatively, when describing the first steering axis and the second steering axis using spherical polar coordinates, the radial coordinate may be regarded as a first coordinate of the first steering axis, and the azimuth coordinate may be regarded as a second coordinate of the second steering axis.

The rotation of the first and second optical elements may provide a one-to-one mapping of the associated changes of the first and second steering coordinates. Rotating one of the optical elements may steer electromagnetic radiation exclusively along an associated steering axis.

In the known electromagnetic radiation steering mechanism, the first angle and the second angle are equal. That is, to achieve orthogonal steering axes to steer electromagnetic radiation about a two-dimensional field of view, the first and second axes of rotation are also orthogonal. Thus, in known electromagnetic radiation steering mechanisms, the axis of rotation and the steering axis may be described as being directly coupled. The electromagnetic radiation steering mechanism disclosed herein advantageously decouples the orientation of the first and second axes of rotation of the first and second optical elements from the orientation of the first and second steering axes, allowing for greater design freedom and a wider range of applications.

The electromagnetic radiation steering mechanism disclosed herein advantageously decouples the orientation of the first and second axes of rotation of the first and second optical elements from the orientation of the first and second steering axes, allowing for greater design freedom. The electromagnetic radiation steering mechanism may be used in a wide range of applications, including applications in which known electromagnetic radiation steering mechanisms are unsuitable due to their size and/or weight. One such application involves marking a product on a production line using a laser marking system by incorporating an electromagnetic radiation steering mechanism into a marking head. The electromagnetic radiation steering mechanism according to the present invention may enable the use of smaller, lighter marking heads, thereby simplifying the installation of the laser marking system, and also giving greater flexibility on how the marking heads are used on a production line.

The first and second axes of rotation may be non-orthogonal.

Having non-orthogonal first and second axes of rotation advantageously provides greater freedom of physical arrangement of the first and second optical elements even when the first and second steering axes are orthogonal.

The first axis of rotation and the second axis of rotation may be substantially parallel.

Having substantially parallel first and second axes of rotation advantageously provides a compact arrangement of the first and second optical elements, thereby reducing the size and weight of the electromagnetic radiation steering mechanism. This reduction in size and weight advantageously allows the electromagnetic radiation steering mechanism to be used in a greater number of applications where size and/or weight may have previously been a limiting factor, such as the marking head of a laser marking system.

The first angle may be less than about 45 °. The first angle may be less than about 10 °. The first angle may be less than about 5 °. The first angle may be less than about 2 °. The first angle may be about 0 °.

Reducing the range of the first angle may advantageously result in a more compact electromagnetic radiation steering mechanism.

The first steering axis and the second steering axis may be substantially orthogonal.

Having substantially orthogonal first and second steering axes may advantageously provide a full two-dimensional field of view around which electromagnetic radiation may be steered by an electromagnetic radiation steering mechanism.

The second angle may be between about 70 ° and about 110 °. The second angle may be between about 80 ° and about 100 °. The second angle may be between about 85 ° and about 95 °. The second angle may be about 90 °.

The electromagnetic radiation manipulator may be configured to introduce a difference of greater than about 45 ° between the first angle and the second angle. The electromagnetic radiation manipulator may be configured to introduce a difference of greater than about 70 ° between the first angle and the second angle. The electromagnetic radiation manipulator may be configured to introduce a difference of about 90 ° between the first angle and the second angle.

Increasing the difference between the first angle and the second angle introduced by the electromagnetic radiation manipulator up to about 90 ° may advantageously further decouple the orientation of the rotation axis from the orientation of the steering axis. This, in turn, may advantageously provide greater design freedom when assembling the first optical element and the second optical element, without having to reduce and/or limit the two-dimensional field of view around which the electromagnetic radiation may be steered.

The first optical element may be adjacent to the second optical element. The first and second optical elements may be offset from each other along a direction parallel to the first and/or second axis of rotation. The minimum distance may exist between the first and second axes of rotation. That is, the amount of space between the first optical element and the second optical element can be reduced in order to further reduce the size of the electromagnetic radiation steering mechanism. The size of the first optical element and the second optical element may at least partially determine a minimum distance between the first axis of rotation and the second axis of rotation. The range of rotation of the first and second optical elements (i.e., the maximum and/or minimum angles by which the first and second optical elements may be rotated about the first and second axes of rotation) may at least partially determine the minimum distance between the first and second axes of rotation. If the distance between the first and second rotation axes is insufficient, the first and second optical elements may contact each other while rotating. The size of the first actuator and/or the second actuator may at least partially determine the minimum distance between the first axis of rotation and the second axis of rotation. The first actuator and/or the second actuator may be mounted such that their size does not determine the minimum distance between the first axis of rotation and the second axis of rotation.

The first optical element may be configured to receive electromagnetic radiation and direct the electromagnetic radiation to the electromagnetic radiation manipulator. The electromagnetic radiation manipulator may be configured to direct electromagnetic radiation to the second optical element.

The second optical element may be configured to direct electromagnetic radiation to an optical output of the electromagnetic radiation steering mechanism.

The second optical element may be configured to direct electromagnetic radiation to an optical input of an optical device configured to receive the diverted electromagnetic radiation.

The electromagnetic radiation steering mechanism may, for example, be configured to steer electromagnetic radiation around a photosensitive detector and/or between different optical inputs of a given optical device.

At least one of the first optical element and the second optical element may be reflective.

Rotation of the reflective optical element may redirect electromagnetic radiation reflected from the reflective optical element.

The first optical element may include a first reflective surface configured to receive electromagnetic radiation. The second optical element may include a second reflective surface configured to receive electromagnetic radiation.

The first optical element and/or the second optical element may comprise a reflective coating, such as, for example, a coating comprising gold and/or silver.

The second reflective surface may be larger than the first reflective surface. This may ensure that the electromagnetic radiation reflected by the first reflective surface is received by the second reflective surface across the range of rotation of the first reflective surface. That is, the second reflective surface may be large enough to receive electromagnetic radiation after a maximum rotation of the first reflective surface in either direction about the first axis of rotation. The turning distance at which the electromagnetic radiation is turned between the first reflective surface and the second reflective surface may be determined at least in part by the distance between the first reflective surface and the second reflective surface. That is, the greater the spacing between the first and second reflective surfaces, the larger the second reflective surface may be in order to still receive the diverted electromagnetic radiation. Accordingly, it may be advantageous to reduce the distance between the first reflective surface and the second reflective surface to reduce and/or limit the turning distance of the electromagnetic radiation within the electromagnetic radiation turning mechanism between the first reflective surface and the second reflective surface.

The first axis of rotation and the first reflective surface may be substantially parallel.

The second axis of rotation and the second reflective surface may be substantially parallel.

At least one of the first optical element and the second optical element may be refractive.

The refractive optical element may be a prism.

At least one of the first optical element and the second optical element may be diffractive.

The diffractive optical element may comprise a grating. The grating may be formed via etching.

At least one of the first optical element and the second optical element may be polarizing.

The polarizing optical element may be configured to change linearly polarized electromagnetic radiation to circularly polarized electromagnetic radiation.

From a laser (e.g. CO)₂Lasers) tend to be linearly polarized. For certain applications (such as, for example, laser marking of products), circularly polarized radiation may be better than linearly polarized radiation.

The electromagnetic radiation manipulator may comprise a first mirror and a second mirror.

The first mirror and/or the second mirror may comprise a reflective coating, such as, for example, a coating comprising gold and/or silver.

The first mirror may be configured to receive electromagnetic radiation after the electromagnetic radiation has interacted with the first optical element and direct the electromagnetic radiation to the second mirror.

The second mirror may be configured to receive electromagnetic radiation after the electromagnetic radiation has interacted with the first mirror and direct the electromagnetic radiation to the second optical element.

The first mirror and the second mirror may be fixed relative to each other.

The first mirror may be arranged to impose an approximately 90 ° change in the direction of the electromagnetic radiation.

The first mirror may be optically disposed at a 45 ° angle relative to the incident electromagnetic radiation.

The second mirror may be arranged to impose an approximately 90 ° change in the direction of the electromagnetic radiation.

The second mirror may be optically disposed at a 45 angle relative to the incident electromagnetic radiation.

A 90 ° change in the direction of the electromagnetic radiation caused by the first mirror may occur about the first reflection axis. The 90 ° change in direction of the electromagnetic radiation caused by the second mirror may occur about the second reflection axis. The first and second reflective axes may be non-parallel.

The first reflection axis may be parallel to and/or coplanar with a surface of the first mirror from which the electromagnetic radiation is reflected. The second axis of reflection may be parallel to and/or coplanar with a surface of the second mirror from which the electromagnetic radiation is reflected.

The first and second reflective axes may be substantially perpendicular.

The first mirror may change a direction of propagation of the electromagnetic radiation in three-dimensional space about the first axis by up to about 90 °. The second mirror may change a direction of propagation of the electromagnetic radiation in three-dimensional space about the second axis by up to about 90 °. The first and second axes may be different. The first axis and the second axis may be non-parallel. The first axis and the second axis may be perpendicular.

At least one of the first actuator and the second actuator may include a galvanometer motor. Alternatively, at least one of the first actuator and the second actuator may include a piezoelectric driver, a magnetic driver, a dc driver, a stepper motor, a servo motor, or the like.

Rotation of the first or second optical element by an angle of x ° may change the direction of propagation of the electromagnetic radiation by an angle of 2x ° since the electromagnetic radiation undergoes reflection from the first or second optical element.

The displacement of the electromagnetic radiation within the two-dimensional field of view caused by the rotation of the first optical element or the second optical element may be determined using trigonometry with knowledge of the angle of rotation of the first optical element or the second optical element and knowledge of the focal length between the electromagnetic radiation steering mechanism and the two-dimensional field of view. Each actuator may, for example, be configured to rotate each optical element by about ± 20 °.

The electromagnetic radiation may be a laser beam. The electromagnetic radiation may be, for example, made of CO₂Laser generation. Electromagnetic radiation may include infrared radiation, near infrared radiation, ultraviolet radiation, visible radiation, and the like. The electromagnetic radiation may have a power of about 5W or more. The electromagnetic radiation may have a power of about 10W or more. The electromagnetic radiation may have a power of about 100W or less. The electromagnetic radiation may have a power of about 100 kW or less.

The electromagnetic radiation may have a beam width greater than about 0.01 mm. The electromagnetic radiation may have a beam width of less than about 10 mm. For example, the electromagnetic radiation may have a beam width of about 5 mm.

According to a second aspect of the present invention there is provided a laser marking system for marking a product comprising a marking head and the electromagnetic radiation steering mechanism of the first aspect of the present invention.

The laser marking system may comprise a radiation source, such as a laser. The laser may be a lower power laser (e.g., suitable power for marking, engraving, flexographic printing, etc. consumer goods). The laser may be a higher power laser (e.g., suitable power for 3D printing, ablation devices, digital cutters, etc.).

The first axis of rotation and the second axis of rotation may be substantially parallel. The electromagnetic radiation steering mechanism may be mounted substantially parallel to a marking head of the laser marking system such that a length of the marking head is substantially parallel to the first axis of rotation and the second axis of rotation.

Known laser marking systems typically include bulky and heavy marking heads sized to accommodate an electromagnetic radiation steering mechanism having orthogonal first and second optical elements. The electromagnetic radiation steering mechanism of the first aspect of the invention advantageously enables parallel first and second optical elements, which in turn enables parallel, rather than perpendicular, mounting of the marking head of the laser marking system. Mounting the electromagnetic radiation steering mechanism substantially parallel to the length of the marking head (i.e., the largest of the three dimensions) of the laser marking system advantageously reduces the size and weight of the marking head, thereby enabling a greater variety of uses and mounting environments, as compared to known laser marking systems. The length may be referred to as the axis or major axis of the headed head.

The marking head may include a cylindrical housing.

The cylindrical housing may have a diameter of about 40 mm. The cylindrical housing may have a length of about 350 mm. The cylindrical housing may have dimensions substantially similar to a marking head available from model 1860 continuous inkjet printer, available from wooddell, video jet Technologies, inc. The heading head may have a weight of about 0.5 kg or less.

The laser marking system may further include a flexible umbilical (flexible tubular) connected to the marking head. The flexible umbilical may be configured to transmit power and/or control signals to the marking head.

The marking head may include a radiation shield for protecting a user of the laser marking system from stray radiation.

The radiation shield may include a sensor configured to detect radiation emitted from a gap between a portion of the radiation shield and the product.

The sensor may be configured to detect escaping radiation to determine whether the radiation shield blocks an appropriate amount of stray light to meet laser safety requirements. The sensor may be configured to detect radiation emitted from the product. For example, the sensor may be configured to detect radiation that has been scattered from the product.

The radiation shield may include an integrated extraction inlet that is fluidly coupled to an extraction device. The extraction device may be configured to generate a flow of extraction fluid to extract a substance resulting from an interaction between the laser beam and the product.

The integration of the extraction inlet and the flow of extraction fluid advantageously allows the removal of substances (e.g., debris, gas, etc.) generated when the electromagnetic radiation is incident on the product to be marked.

The integrated extraction inlet can be configured to be positioned substantially adjacent to the product.

The radiation shield may include a flange to provide further protection from stray radiation to a user of the laser marking system.

The flange may take the form of a labyrinth or a conical projection from a lower portion of the radiation shield.

The radiation shield may comprise a flexible member arranged to reduce a gap between the radiation shield and the product in order to provide further protection from stray radiation to a user of the laser marking system. The flexible member may be a brush.

The laser marking system may further include a variable optical path length assembly configured to define an optical path from the input to the output.

The headed head may further comprise a variable optical path length component configured to define an optical path from the input to the output. The variable optical path length assembly includes a rotatable path length adjuster. The rotatable path length adjuster is configured to: rotating about an axis, receiving a radiation beam along an input path; directing a beam of radiation along a first intermediate path; receiving a beam of radiation along a second intermediate path; and directing the beam of radiation along an output path. The variable optical path length assembly further includes a fixed optical element. The fixed optical element is configured to: receiving a beam of radiation directed by a rotatable path length adjuster along a first intermediate path; and directing the beam of radiation along a second intermediate path back to the rotatable path length adjuster. The geometric path length between the input and the output varies as a function of the angular position of the rotatable path length adjuster. The output path is independent of the angular position of the rotatable path-length adjuster.

By providing a path-length adjuster that provides a variable geometric path length depending on the angular position of the rotatable path-length adjuster, the path length can be accurately and precisely varied while avoiding the limitations associated with conventional linear path-length adjustment devices. The optical path between the input and the output may comprise a plurality of sub-paths, each sub-path being provided between two optical components.

Furthermore, by arranging the rotatable path length adjuster such that the output path is independent of the angular position of the rotatable path length adjuster (and therefore independent of the path length), a fixed relationship may be provided between the input and output paths such that the variable optical path length component may be incorporated into a heading head having a fixed geometry.

The axis about which the path length adjuster is configured to rotate may have a fixed spatial relationship to the input and output. Thus, when the path length adjuster is rotated about an axis, the path length adjuster may be considered to have an angular relationship with the input and output, or an angular position relative to a fixed reference.

By providing a fixed optical element configured to receive radiation along a first intermediate path and direct the radiation beam back to the optical path length adjuster along a second intermediate path, a first intermediate path angle is defined between the first intermediate path and the portion of the rotatable path length adjuster that causes radiation to be directed along the first intermediate path. A second intermediate path angle is defined between the second intermediate path and the portion of the rotatable path length adjuster that receives radiation along the second intermediate path. The first intermediate path angle and the second intermediate path angle may vary in a correlated manner depending on the angular position of the rotatable path-length adjuster.

The geometric path length between the input and the output may be continuously variable depending on the angular position of the rotatable path length adjuster. By providing a path-length adjuster that provides a continuously variable geometric path length depending on the angular position of the rotatable path-length adjuster, the path length can be varied accurately and precisely without having to rely on discrete path-length options (none of which may be tailored to specific requirements).

The rotatable path length adjuster may include a first optical component configured to receive the radiation beam along the input path and to direct the radiation beam along a third intermediate path. The rotatable path length adjuster may include a second optical component configured to receive the radiation beam along a third intermediate path and to direct the radiation beam along the first intermediate path.

An incident radiation beam provided along the input path may first be guided (e.g. reflected) by the first optical component (along the third intermediate path) and then further guided (e.g. reflected) by the second optical component (along the first intermediate path). By providing each of the first and second optical components as part of a rotatable path length adjuster, the inclination and position of each of those elements can be varied by rotating the rotatable path length adjuster, thereby varying the path length.

The variable optical path length assembly may be configured such that rotation of the rotatable path length adjuster about the axis results in: defining a first change in a first angle between the input path and a portion of the first optical component with which the radiation beam interacts; and a second variation of a second angle defined between the input path and the portion of the second optical component with which the radiation beam interacts. The first variation and the second variation may be equal in magnitude but opposite in direction.

For example, although the first and second optical components may each be rotated about the same axis by the same angle, the portions of the optical components that interact with the radiation beam may face in opposite directions, resulting in the same rotation of the rotatable path length adjuster, increasing the angle between the input path and one element, and decreasing the angle between the input path and the other element. In this way, the variable optical path length assembly can be configured to change the path length without changing the direction of the output beam.

It will be appreciated that although the angle of the second optical component is defined above with reference to the input path, the second optical component may not interact directly with the input path. However, the input path is used to provide a convenient directional reference to which other directions or inclinations (and in particular, changes in direction or inclination) can be compared.

The first optical component and the second optical component may have a fixed spatial relationship such that rotation of the rotatable path length adjuster about the axis of rotation causes the first optical component and the second optical component to rotate about the axis of rotation. By providing a fixed spatial relationship between the first optical component and the second optical component, the relationship between the input path and the first intermediate path may remain fixed regardless of the angular position of the rotatable path length adjuster. That is, variable angular variations in the angle between the radiation beam formed by the movement of the first optical component and the first optical component may be compensated by corresponding angular variations formed by the movement action of the second optical component, resulting in a fixed angular relationship between the input path and the first intermediate path.

Once the incident radiation beam has been directed along the first intermediate path by the first and second optical components, the beam may be reflected by the fixed optical element back to the rotatable path length adjuster along the second intermediate path.

The radiation beam provided along the second intermediate path may then be redirected (e.g. reflected) by the second optical component so as to travel along the fourth intermediate path. The radiation beam may then be further directed (e.g., reflected) by the first optical component to travel along an output path.

Thus, by providing each of the first and second optical components as part of a rotatable path length adjuster, the inclination and position of each of those elements can be varied by rotating the rotatable path length adjuster, thereby varying the path length, and directing the incident radiation beam from input to output as required.

The first optical component may include a first reflective surface configured to receive the radiation beam along the input path and to direct the radiation beam along a third intermediate path. The second optical component may include a second reflective surface configured to receive the radiation beam along a third intermediate path and to direct the radiation beam along the first intermediate path. The first optical component may comprise a first reflector. The second optical component may comprise a second reflector.

The second optical component may be configured to receive the radiation beam along a second intermediate path and to direct the radiation beam along a fourth intermediate path. The first optical component may be configured to receive the radiation beam along a fourth intermediate path and to direct the radiation beam along an output path.

The first reflective surface may be a flat surface. The second reflective surface may be a flat surface. The first and second reflective surfaces may be substantially parallel to each other.

An incident radiation beam provided along the input path may be first reflected by the first reflective surface (along the third intermediate path) and then reflected by the second reflective surface (along the first intermediate path). By providing parallel first and second reflective surfaces, the relationship between the input path and the first intermediate path may be maintained parallel regardless of the angular position of the rotatable path-length adjuster. That is, the variable angular variation formed by the reflection of the first reflective surface will be compensated by the corresponding angular variation formed by the reflection of the second reflective surface, resulting in a fixed angular relationship between the input path and the first intermediate path.

A similar relationship may be provided for the return optical path from the fixed optical element, resulting in a second intermediate path and remaining parallel to the output path regardless of the angular position of the rotatable path-length adjuster.

The angle defined between each of the first and second reflective surfaces and the axis of rotation may be substantially the same.

By providing the first and second reflective surfaces such that they each have a substantially equal angle to the axis of rotation, rotation of the rotatable path length adjuster can be caused to change the path length in one direction (i.e. along the direction of propagation) without causing any change in the position of the output path relative to the input path in a direction perpendicular to the direction of beam propagation. Any shift in beam position in a direction perpendicular to the direction of beam propagation caused by one of the reflective surfaces may be cancelled by the other of the reflective surfaces. Resulting in the output path remaining independent of rotational position (and associated geometric path length).

The first and second reflective surfaces may be substantially parallel to the axis of rotation. The input path may be substantially perpendicular to the axis of rotation. The output path may be substantially perpendicular to the axis of rotation. The input path may be substantially parallel to the output path.

By providing the first and second reflective surfaces such that they are substantially parallel to the axis of rotation, the angle of those surfaces relative to the input path that is substantially perpendicular to the axis of rotation will not change as the rotatable path length adjuster rotates about the axis. In this way, rotation of the rotatable path length adjuster may be caused to vary the path length in one direction (i.e. along the direction of propagation) without causing any change in the position of the output path relative to the input path in a direction perpendicular to the direction of beam propagation, thereby enabling optical elements positioned at the output and input to remain fixed in position despite the path length change.

The rotatable path length adjuster may include a rotatable base. The first and second optical components may be mounted on a rotatable base. The various components mounted on the rotatable base may be fixedly mounted such that any rotation of the rotatable base about the axis results in a corresponding rotation of each of the various mounted components about the axis.

The variable optical path length assembly may include a first reflector mounted on and extending from the rotatable base, and a second reflector mounted on and extending from the rotatable base. The first reflector and/or the second reflector may each extend in a direction substantially parallel to the axis of rotation of the base.

Depending on the distance between a particular optical component (and more particularly the portion of the particular optical component that interacts with the radiation beam) and the axis, rotation about the axis will result in a change in the length of the sub-path associated with the optical component.

The geometric path length may be configured to vary as a function of the angular position of the rotatable path length adjuster within a predetermined angular range. The predetermined angular range may be, for example, 20 degrees, which may, for example, include a variation of plus or minus 10 degrees from a neutral or default position.

If the angular position of the rotatable path-length adjuster varies beyond a predetermined range, various optical components may begin to interfere with various intermediate optical paths. As such, by limiting the range of motion to a predetermined range, any performance loss may be avoided.

According to a third aspect of the present invention there is provided an electromagnetic radiation detector comprising the electromagnetic radiation steering mechanism of the first aspect of the present invention.

The electromagnetic radiation detector may form part of a camera. The electromagnetic radiation detector may form part of a time-of-flight sensor.

The first axis of rotation and the second axis of rotation may be substantially parallel. The electromagnetic radiation steering mechanism may be mounted substantially parallel to the electromagnetic radiation detector such that a length of the electromagnetic radiation detector is substantially parallel to the first and second axes of rotation.

Known electromagnetic radiation detectors typically include a bulky and heavy housing sized to accommodate an electromagnetic radiation steering mechanism having orthogonal first and second optical elements. The electromagnetic radiation steering mechanism of the first aspect of the invention advantageously enables parallel first and second optical elements, which in turn enables parallel mounting (rather than perpendicular mounting) of the housing of the electromagnetic radiation detector. Mounting the electromagnetic radiation steering mechanism substantially parallel to the length of the housing of the electromagnetic radiation detector (i.e., the largest of the three dimensions) advantageously reduces the size and weight of the housing, thereby enabling a greater variety of uses and mounting environments, as compared to known electromagnetic radiation detectors. The length may be referred to as the axis or main axis of the electromagnetic radiation detector.

The electromagnetic radiation detector may be configured to transmit and receive electromagnetic radiation (e.g., as a time-of-flight sensor).

According to a fourth aspect of the present invention there is provided an optical scanner comprising the electromagnetic radiation steering mechanism of the first aspect of the present invention.

The optical scanner may form part of a medical device, such as, for example, a skin resurfacing device.

The first axis of rotation and the second axis of rotation may be substantially parallel. The electromagnetic radiation steering mechanism may be mounted substantially parallel to the optical scanner such that the length of the optical scanner is substantially parallel to the first axis of rotation and the second axis of rotation.

Known optical scanners typically include a bulky and heavy housing sized to accommodate an electromagnetic radiation steering mechanism having orthogonal first and second optical elements. The electromagnetic radiation steering mechanism of the first aspect of the invention advantageously enables parallel first and second optical elements, which in turn enables parallel mounting (rather than perpendicular mounting) of the housing of the optical scanner. Mounting the electromagnetic radiation steering mechanism substantially parallel to the length of the housing of the optical scanner (i.e., the largest of the three dimensions) advantageously reduces the size and weight of the housing, thereby enabling a greater variety of uses and mounting environments, as compared to known optical scanners. The length may be referred to as the axis or principal axis of the optical scanner.

The optical scanner may include a laser source configured to generate and direct electromagnetic radiation in a direction parallel to the first axis of rotation and the second axis of rotation.

According to a fifth aspect of the present invention there is provided a method of steering electromagnetic radiation to address a particular location within a two-dimensional field of view, comprising: receiving electromagnetic radiation at a first optical element, the first optical element being rotatable about a first axis of rotation to change a first coordinate of a first steering axis in the two-dimensional field of view; directing the electromagnetic radiation to an electromagnetic radiation manipulator optically disposed between the first optical element and the second optical element; directing the electromagnetic radiation to the second optical element, the second optical element being rotatable about a second axis of rotation to change a second coordinate of a second steering axis in the two-dimensional field of view; defining a first angle between the first and second axes of rotation; defining a second angle between the first and second steering axes; and using an electromagnetic radiation manipulator to introduce a difference between the first angle and the second angle.

According to a sixth aspect of the present invention, there is provided a method of marking a product using an electromagnetic radiation steering mechanism, comprising: receiving electromagnetic radiation at a first optical element, the first optical element being rotatable about a first axis of rotation to change a first coordinate of a first steering axis in the two-dimensional field of view; directing the electromagnetic radiation to an electromagnetic radiation manipulator optically disposed between the first optical element and the second optical element; directing the electromagnetic radiation to the second optical element, the second optical element being rotatable about a second axis of rotation to change a second coordinate of a second steering axis in the two-dimensional field of view; defining a first angle between the first and second axes of rotation; defining a second angle between the first and second steering axes; using an electromagnetic radiation manipulator to introduce a difference between the first angle and the second angle; and diverting the electromagnetic radiation around the product by rotating the first and second optical elements.

The electromagnetic radiation steering mechanism may be located within a marking head of the laser marking system. The method may further include moving the marking head during marking.

The compact and lightweight electromagnetic radiation steering mechanism disclosed herein enables movement of a marking head during marking of a product. This advantageously increases the flexibility with which the heading can be used. For example, the marking head may be attached to a robotic assembly configured to move the marking head and thereby maintain a desired distance from the curved product to be marked using the marking head.

According to a seventh aspect of the present invention, there is provided a method of detecting electromagnetic radiation, comprising: receiving electromagnetic radiation at a first optical element, the first optical element being rotatable about a first axis of rotation to change a first coordinate of a first steering axis in the two-dimensional field of view; directing the electromagnetic radiation to an electromagnetic radiation manipulator optically disposed between the first optical element and the second optical element; directing the electromagnetic radiation to the second optical element, the second optical element being rotatable about a second axis of rotation to change a second coordinate of a second steering axis in the two-dimensional field of view; defining a first angle between the first and second axes of rotation; defining a second angle between the first and second steering axes; and using an electromagnetic radiation manipulator to introduce a difference between the first angle and the second angle.

The method may further comprise imaging the object using electromagnetic radiation.

According to an eighth aspect of the present invention, there is provided a method of assembling an electromagnetic radiation steering mechanism, comprising: mounting a first optical element and an associated first actuator, the first actuator configured to rotate the first optical element about a first axis of rotation to change a first coordinate of a first steering axis in the two-dimensional field of view; mounting a second optical element having an associated second actuator configured to rotate the second optical element about a second axis of rotation to change a second coordinate of a second steering axis in the two-dimensional field of view; and optically disposing an electromagnetic radiation manipulator between the first optical element and the second optical element.

According to a ninth aspect of the present invention there is provided a method of retrofitting a production system comprising a continuous inkjet marking system, comprising replacing the continuous inkjet marking system with the laser marking system of the second aspect of the present invention.

The compact size and increased mobility of the laser marking systems disclosed herein makes it much easier to replace continuous inkjet marking systems with laser marking systems, as compared to known laser marking systems.

According to another aspect of the present invention, there is provided an electromagnetic radiation steering mechanism including: a first rotary actuator coupled to the first reflective surface; a second rotary actuator coupled to the second reflective surface; and an electromagnetic radiation spatial distribution rotator optically disposed between the first reflective surface and the second reflective surface.

According to another aspect of the present invention, there is provided an electromagnetic radiation steering mechanism including: a first rotary actuator coupled to the first deflector; a second rotary actuator coupled to the second deflector; and an electromagnetic radiation spatial distribution rotator optically disposed between the first deflector and the second deflector.

According to another aspect of the present invention, there is provided an electromagnetic radiation steering mechanism including: a first variable deflector; a second variable deflector; and an electromagnetic radiation spatial distribution rotator optically operable between the first deflector and the second deflector.

According to another aspect of the present invention, there is provided an electromagnetic radiation steering mechanism including: a first variable deflector; a second variable deflector; and an electromagnetic radiation spatial distribution transformer disposed between the first deflector and the second deflector.

According to another aspect of the present invention, there is provided an electromagnetic radiation steering mechanism including: a first variable deflector; and a second variable deflector, wherein the effective deflection axis of the first deflector is substantially orthogonally transformed.

According to another aspect of the present invention, there is provided an electromagnetic radiation steering mechanism including: a first variable deflector; and a second variable deflector, wherein the first variable deflector directs radiation in a linear fashion over the second variable deflector, and the second variable deflector further directs radiation in an angular motion.

The first variable deflector may be a spatially distributed rotator.

The first variable deflector may be etched.

The first variable deflector may be a mirror.

The electromagnetic radiation may be a laser beam.

The electromagnetic radiation steering mechanism may be provided in a housing having a skirt extending from an electromagnetic radiation output side of the housing, the skirt being constructed and arranged to absorb electromagnetic radiation scattered from an object to which the electromagnetic radiation is directed by the mechanism.

The electromagnetic radiation steering mechanism may further include a cleaning subsystem including an air source and an exhaust, the cleaning subsystem being constructed and arranged to remove particulate matter from around the surface of the object to which the electromagnetic radiation is directed by the mechanism.

According to another aspect of the present invention, there is provided an electromagnetic radiation steering mechanism including: a first deflector; a second deflector; and an electromagnetic radiation spatial distribution rotator disposed between the first deflector and the second deflector.

At least one of the first deflector and the second deflector may be a variable deflector.

At least one of the first deflector and the second deflector may be a reflector.

At least one of the first deflector and the second deflector may be a mirror.

At least one of the first deflector and the second deflector may be refractive.

At least one of the first deflector and the second deflector may be a prism.

The electromagnetic radiation may be a laser beam.

The first deflector may include a first reflective surface, and the first deflector may be coupled to a first actuator having an axis of rotation parallel to the first reflective surface.

The second deflector may include a second reflective surface, and the second deflector may be coupled to a second actuator having an axis of rotation parallel to the second reflective surface and the first reflective surface.

The first axis of rotation may be substantially parallel to the second axis of rotation.

The rotator may comprise at least two rotator deflectors positioned between the first reflective surface and the second reflective surface, wherein the combination of the rotator deflectors is constructed and arranged to cause a substantially orthogonal transformation of the spatial distribution of electromagnetic radiation.

The rotator may comprise two orthogonal rotator deflectors.

The mechanism may comprise a two-axis optical scanner.

According to another aspect of the present invention, there is provided a camera comprising the electromagnetic radiation steering mechanism discussed above.

According to another aspect of the present invention there is provided a product marking machine comprising the electromagnetic radiation turning mechanism discussed above.

The electromagnetic radiation steering mechanism may include a product marking machine.

According to another aspect of the invention, there is provided a method of steering electromagnetic radiation, the method comprising: directing the electromagnetic radiation to a first variable deflector; and deflecting electromagnetic radiation from a first variable deflector to a second variable deflector and through an electromagnetic radiation spatial distribution rotator disposed between the first variable deflector and the second variable deflector.

According to another aspect of the present invention, there is provided a method of assembling an electromagnetic radiation steering mechanism, the method comprising: mounting a first variable deflector within a housing; mounting a second variable deflector within the housing; and mounting an electromagnetic radiation spatial distribution rotator in the housing between the first variable deflector and the second variable deflector.

According to another aspect of the present invention, there is provided a method of marking a product, the method comprising: directing electromagnetic radiation to a first variable deflector in a housing of an electromagnetic radiation steering mechanism; deflecting electromagnetic radiation from a first variable deflector to a second variable deflector and through an electromagnetic radiation spatial distribution rotator disposed between the first variable deflector and the second variable deflector; and deflecting electromagnetic radiation from the second variable deflector to the surface of the product.

The method may further comprise: receiving electromagnetic radiation from a surface of the product through an aperture in a housing of the electromagnetic radiation steering mechanism and onto the second variable deflector; deflecting electromagnetic radiation from a second variable deflector to a first variable deflector and through an electromagnetic radiation spatial distribution rotator disposed between the first variable deflector and the second variable deflector; and directing electromagnetic radiation from the first variable deflector to an electromagnetic radiation detector.

According to another aspect of the invention, there is provided a method of imaging an object, the method comprising: receiving electromagnetic radiation from an object through an aperture in a housing of an electromagnetic radiation steering mechanism and onto a first variable deflector disposed within the housing; deflecting electromagnetic radiation from a first variable deflector to a second variable deflector and through an electromagnetic radiation spatial distribution rotator disposed between the first variable deflector and the second variable deflector; and directing electromagnetic radiation from the second variable deflector to an electromagnetic radiation detector.

According to another aspect of the present invention, there is provided an optical scanner including: a first drive mechanism having a first drive mechanism reflector; and a second drive mechanism having a second drive mechanism reflector, the second drive mechanism having an axis of rotation parallel to the axis of rotation of the first drive mechanism, the second drive mechanism positioned adjacent to the first drive mechanism.

The optical scanner may further include a laser source configured to direct a laser beam into the optical scanner in a direction parallel to the rotational axes of the first and second drive mechanisms.

The optical scanner may further include a first reflector positioned and arranged to receive the laser beam after the laser beam is reflected by the first drive mechanism reflector to change an optical path of the laser beam reflected by the first drive mechanism reflector by 90 degrees.

The optical scanner may further include a second reflector positioned and arranged to receive the laser beam after the laser beam is reflected by the first reflector, to change an optical path of the laser beam reflected by the first reflector by an additional 90 degrees, and to direct the laser beam toward the second drive mechanism reflector.

The optical scanner may further include a third reflector positioned and arranged to change the optical path of the laser beam by 90 degrees and reflect the laser beam from the laser source onto the first drive mechanism reflector.

The optical scanner may further include a fourth reflector positioned and arranged to receive the laser beam after reflection by the laser beam second drive mechanism reflector and to change the optical path of the laser beam by an additional 90 degrees and direct the laser beam through an output aperture of the optical scanner.

The optical scanner may further include an electromagnetic energy sensor positioned and arranged to receive electromagnetic energy from an object external to the optical scanner and reflected from the first drive mechanism mirror and the second drive mechanism motor.

According to one aspect, an optical scanner is provided. The optical scanner includes a first drive mechanism having a first drive mechanism mirror and a second drive mechanism having a second drive mechanism mirror. The second drive mechanism has an axis of rotation parallel to the axis of rotation of the first drive mechanism. The second drive mechanism is positioned adjacent to the first drive mechanism.

In some embodiments, the optical scanner further comprises a laser source configured to direct a laser beam into the optical scanner in a direction parallel to the axes of rotation of the first and second drive mechanisms.

In some embodiments, the optical scanner further comprises a first mirror positioned and arranged to reflect the laser beam from the laser source onto the first drive mechanism mirror.

In some embodiments, the optical scanner further comprises a second mirror positioned and arranged to receive the laser beam after the laser beam is reflected by the first drive mechanism mirror and to change the optical path of the laser beam reflected by the first drive mechanism mirror by 90 degrees.

In some embodiments, the optical scanner further comprises a third mirror positioned and arranged to receive the laser beam after the laser beam is reflected by the second mirror and to change the optical path of the laser beam reflected by the second mirror by an additional 90 degrees and direct the laser beam toward the second drive mechanism mirror.

In some embodiments, the optical scanner further comprises a fourth mirror positioned and arranged to receive the laser beam after the laser beam is reflected by the second drive mechanism mirror and to change the optical path of the laser beam by an additional 90 degrees and direct the laser beam through the output aperture of the optical scanner.

Of course, it will be appreciated that features described in the context of one aspect of the invention may be combined with features described in the context of another aspect of the invention. For example, features described in the context of the first aspect of the invention or/and components of the second to ninth aspects of the invention may be combined with each other and also with features of the other aspects of the invention described above and vice versa.

Drawings

The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which:

FIG. 1 is an elevation view of a pair of galvanometer motors and associated mirrors and a laser beam entering a laser scanner;

FIG. 2 is a side view of the pair of galvanometer motors and associated mirrors of FIG. 1 and a laser beam;

FIG. 3 is a front view of the pair of galvanometer motors and associated mirrors of FIG. 1 and a first mirror arranged to reflect the laser beam of FIG. 1 onto a first one of the galvanometer motor mirrors;

FIG. 4 is an isometric view of the pair of galvanometer motors and associated mirror and first mirror of FIG. 3;

FIG. 5 is an isometric view of the pair of galvanometer motors and associated mirrors of FIG. 1 and second and third mirrors arranged to reflect the laser beam reflected by the first galvanometer motor mirror onto a second one of the galvanometer motor mirrors;

FIG. 6 is a side view of the pair of galvanometer motors and mirrors of FIG. 5 and a laser beam;

FIG. 7 is another side view of the pair of galvanometer motors and mirrors of FIG. 5 and a laser beam;

FIG. 8 is a front view of the pair of galvanometer motors and associated mirrors of FIG. 1 and a fourth mirror arranged to reflect the laser beam reflected by the second galvanometer mirror onto the workpiece;

FIG. 9 is a side view of the pair of galvanometer motors and mirrors of FIG. 8;

FIG. 10 shows a laser beam deflection range that can be achieved with a laser scanner;

FIG. 11 shows the range of laser beam deflection that can be achieved with a laser 20 scanner;

FIG. 12 is an isometric view of the pair of galvanometer motors and associated mirrors of FIG. 1 and first through fourth mirrors;

FIG. 13 is a side view of the pair of galvanometer motors and associated mirrors of FIG. 1 and first through fourth mirrors;

fig. 14 shows a housing of the laser scanner (i.e., a housing of the electromagnetic radiation steering mechanism);

FIG. 15 is a side view of an electromagnetic radiation steering mechanism including an electromagnetic radiation manipulator according to an embodiment of the present invention;

FIG. 16 is a side view of the electromagnetic radiation steering mechanism of FIG. 15 further including a third reflector in accordance with an embodiment of the present invention;

FIG. 17 is a side view of the electromagnetic radiation steering mechanism of FIG. 15 further including a fourth reflector in accordance with an embodiment of the present invention;

FIG. 18 is a side view of the electromagnetic radiation steering mechanism of FIG. 16 further including a collimator and focusing optics in accordance with an embodiment of the present invention;

FIG. 19 is a side view of a marking head of a laser marking system including an electromagnetic radiation steering mechanism according to an embodiment of the present invention;

FIG. 20 is a side view of the headed head of FIG. 19 further including an umbilical according to an embodiment of the invention; and the number of the first and second electrodes,

fig. 21A and 21B illustrate an embodiment of the variable optical path length apparatus in a plan view and a perspective view, respectively.

Detailed Description

The aspects and embodiments disclosed herein are not limited in the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The aspects and embodiments disclosed herein are capable of being practiced or of being carried out in various ways.

Aspects and embodiments disclosed herein include a system for scanning or diverting a laser beam of a laser scanning or marking system and a laser scanning or marking system including such a system. Laser marking systems may be used in production lines for various types of articles. Laser marking systems may be used to imprint bar codes, unique identification marks, expiration dates, or other information on items passing through a production line. In some embodiments, a carbon dioxide (CO 2) gas laser may be used in a laser marking system. The carbon dioxide laser produces infrared beams centered in four major bands of 9.3, 9.6, 10.2, and 10.6 microns (μm). The lasers used in laser marking systems typically operate at laser power levels of tens of watts.

However, laser scanning or marking systems are not limited to the use of a CO2 laser. In some aspects and embodiments, the optical scanner or marker may utilize a laser operating in ultraviolet, visible, or near infrared wavelengths or any other type of laser or optical illumination source. The use of visible light laser beams in laser scanner systems may be advantageous because the user can see the laser beam where it illuminates the scanned object, and thus the user can adjust the position of the laser scanner or the scanned object so that the laser illuminates the desired portion of the object.

Embodiments of the laser scanners disclosed herein may include at least two mirror turning devices, such as a piezoelectric or magnetic drive, a dc drive, a stepper motor, a servo motor, or a galvanometer with mirrors attached. Subsequently, the term "drive mechanism" will be used as a general term for the different mirror direction changing device. The mirrors used in embodiments of the laser scanner/marking machine disclosed herein may be silver-plated or gold-plated mirrors, or any other suitably coated material. The window and lens used in embodiments of the laser scanner/marker disclosed herein may be, for example, germanium, zinc selenide, quartz, BK7 borosilicate glass, or any other suitable material.

According to some embodiments, the two drive mechanisms of the laser scanning system are arranged with the rotation axes parallel to each other and simultaneously parallel to the incident laser beam. Fig. 1 and 2 show front and side views, respectively, of a pair of drive mechanisms A, B and associated mirrors 100A, 100B of a scan head of a laser scanning/marking system positioned relative to an incident laser beam 105. The drive mechanism A, B may be referred to as first and second actuators. The mirrors 100A, 100B may be considered as examples of first and second optical elements of an electromagnetic radiation steering mechanism.

The two drive mechanisms A, B may be placed as close to each other as possible (minimum distance between the two axes of rotation of the drive mechanisms). The closer the two drive mechanisms A, B may be placed, the smaller the mirror 100B of the second drive mechanism B may be. The two drive mechanisms A, B may be displaced relative to each other on their axes of rotation.

The incident beam is redirected by mirror 110 (fig. 3 and 4) by 90 deg. to hit mirror 100A of the first drive mechanism a. In the example of fig. 3 and 4, when the input beam 105 enters the electromagnetic radiation steering mechanism parallel to the rotational axes of the two drive mechanisms A, B, the mirror 110 is arranged such that the input beam 105 is redirected by the mirror 110 by approximately 90 °. Alternatively, the input beam 105 may enter the electromagnetic radiation steering mechanism perpendicular to the axis of rotation of the two drive mechanisms A, B, in which case the mirror 110 may not be present.

In a standard laser scanner, the deflected beam will be directed to a second drive mechanism oriented generally 90 ° from the first drive mechanism. However, in some aspects and embodiments disclosed herein, the drive mechanisms A, B are parallel.

As shown in fig. 5, 6, and 7, the deflected beam from the drive mechanism a is directed to a fixed mirror "a" that deflects the beam scanning direction by 90 °. That is, in the examples of fig. 5, 6, and 7, the first mirror "a" of the electromagnetic radiation manipulator is configured to change the propagation direction of the electromagnetic radiation within the electromagnetic radiation steering mechanism by 90 °. The deflected beam from mirror "a" is directed to a second fixed mirror "b" which deflects the beam scan direction by 90 °. From there, the deflected beam hits the moving mirror 100B of the drive mechanism B. That is, in the examples of fig. 5, 6, and 7, the second mirror "b" of the electromagnetic radiation manipulator is configured to change the propagation direction of the electromagnetic radiation within the electromagnetic radiation steering mechanism by another 90 °. In total, the electromagnetic radiation manipulators "a", "b" cause the electromagnetic radiation 105 to change the propagation direction twice by about 90 ° within the electromagnetic radiation steering mechanism. The first 90 change in propagation direction occurs about a first plane defined by the orientation of the reflective surface of first mirror "a" relative to electromagnetic radiation 105. The first plane may be substantially aligned with a first reflection axis of the first mirror "a". A second 90 ° change in propagation direction occurs around the vertical plane defined by the orientation of the reflective surface of second mirror "b" with respect to electromagnetic radiation 105. The vertical plane may be substantially aligned with the second reflection axis of the second mirror "b". The two 90 ° changes of the propagation direction caused by the electromagnetic manipulators "a", "b" can occur in three-dimensional space around two different (e.g. perpendicular) axes. The electromagnetic radiation manipulators "a", "B" advantageously allow the parallel optical elements 100A, 100B to be used to steer electromagnetic radiation 105 about a two-dimensional field of view (e.g., a two-dimensional field of view having orthogonal steering axes). The effect of the electromagnetic radiation manipulators "a", "b" on the electromagnetic radiation 105 is shown and discussed further with reference to fig. 15.

This arrangement of the two fixed redirecting mirrors "a", "B" effects a 90 ° redirection of the deflection freedom of the first galvanometer motor a before the beam hits the second galvanometer motor B. That is, rotating the first optical element 100A about the first axis of rotation results in a turning movement of the electromagnetic radiation exiting the electromagnetic radiation turning mechanism that is oriented substantially perpendicular to the first axis of rotation. In other words, the electromagnetic radiation manipulators "a", "B" disclosed herein advantageously decouple the orientation of the first and second axes of rotation of the first and second optical elements 100A, 100B from the orientation of the first and second steering axes of the electromagnetic radiation steering mechanism, allowing for greater design freedom and a wider range of applications.

Finally, after the second degree of freedom of deflection is added by drive mechanism B, deflected beam 105 is redirected again by 90 ° by mirror 115 to face the product (in the direction of arrow 120 in FIGS. 8, 9, 12, and 13).

The two orthogonal degrees of freedom of beam deflection are illustrated by sample rays 105A, 105B, 105C, and 105D in fig. 10 and 11 after the final 90 ° redirection. That is, electromagnetic radiation 105 may be diverted between the positions shown by sample rays 105A-D in FIGS. 10 and 11. Sample rays 105A-D exhibit a maximum extent of a two-dimensional field of view around which electromagnetic radiation may be steered by an electromagnetic radiation steering mechanism.

The entire assembly, including the drive mechanism A, B and all associated mirrors, may be disposed within a cylindrical housing 125, such as that shown in fig. 14. The cylindrical shell 125 may have a diameter of about 40 mm and a length of about 350 mm. The cylindrical housing 125 may also include, for example, a 300 mm long isolator and a 50 mm long beamformer, which would allow the overall length of the cylindrical housing 125 to be 700 mm. The cylindrical housing 125 may have dimensions substantially similar to the print head of a model 1860 continuous inkjet printer available from videojet technologies, inc. Flexible umbilical cord 130 may be coupled to housing 125 and may include power and signal lines to provide power to drive mechanism A, B and control drive mechanism A, B. The umbilical cord 130 may also include optical waveguides, e.g., fiber optic cables, to carry the laser beam from the external laser beam generator into the housing 125. Alternatively, the laser beam generator may be provided within the housing 125 together with other components. The cylindrical housing 125 and enclosed components may form a marking head or scanning head of a laser marking system or an optical scanning system. The lower end of the housing 125 may be sealed by an optically transparent window to prevent debris from entering the housing 125.

In some embodiments, the cylindrical shell 125 may further include a skirt (not shown) extending from a lower end of the cylindrical shell 125. The skirt may be referred to as a radiation shield. When used as a laser marker or optical scanner, the cylindrical housing 125 may be brought near the surface of an object to be scanned or marked. A skirt may extend from the lower end of the cylindrical shell 125 and rest against or near the surface of the object. When scanning or marking an object by blocking light reflected from the surface of the object, the skirt may prevent light (e.g., laser light) from reflecting from the surface of the object toward the eyes of a user or bystander. A flange or labyrinth projection or collar extending radially outwardly from the lower end of the skirt may be used to further prevent light from being scattered from within the skirt. One or more photosensors may be provided on or near the skirt to determine whether light is sufficiently blocked by the skirt. The small form factor of embodiments of the laser marking head disclosed herein may enable the laser marking head to be positioned very close to the marked object, e.g., less than about 10 mm from the marked object. Thus, the skirt may extend less than about 10 mm from the end of the shell 125. Providing a skirt on the housing 125 of the laser marking head may reduce or eliminate the need for large and bulky shields that are typically placed around existing laser marking systems to prevent the laser from reaching the operator or bystanders.

An air circulation system may be included in the skirt to remove any particulate matter emitted from the surface of the object as the object is laser marked. The air circulation system may include an extraction device fluidly coupled to the radiation shield via an integrated extraction inlet. In some embodiments, air from a fan may be directed from one portion of the skirt to the marked object, and a vacuum may be applied to another portion of the skirt to form an "air knife" and integrated exhaust for removing particles due to the marked object. The lower end of the skirt may include a brush to assist in removing debris from the surface of the object. In some embodiments, the skirt may be formed of a flexible material that may be expanded or contracted by adding or removing air or another fluid from the interior volume of the skirt.

The skirt may be a consumable that is removably attached to the housing 125 of the laser marking system head. Thus, the skirt may be replaced periodically or upon becoming damaged or after more debris than desired has accumulated in a filter (e.g., an electrostatic filter) included in the skirt. In some embodiments, the skirt may include an RFID chip or laser marking system for determining whether the skirt is attached to the housing 125 and preventing use of other safety interlocks of the system in the absence of the skirt.

Aspects and embodiments of the laser scanner/marking system disclosed herein may provide advantages not realized in existing systems. In prior systems, the first and second drive mechanisms were typically oriented at 90 ° relative to each other. This makes existing laser scanner/marking systems more bulky than the aspects and embodiments disclosed herein, and therefore more limited in positioning capabilities in production systems. In some examples, existing laser marking heads weigh more than 5 kilograms. In contrast, the laser marking head disclosed herein may weigh about 0.5 kg, which is about one-tenth the weight of many existing systems. The form factor, size, and weight of the aspects and embodiments of the laser scanner/marking systems disclosed herein make the disclosed laser scanner/marking systems easier to manipulate. For example, the marking head of a laser scanner/marking system including housing 125 may be mounted on a movable assembly (e.g., a robotic arm) and may be moved to follow the contour of a three-dimensional object (e.g., a bottle) while maintaining the same focal length, e.g., about 5 mm from the surface of the object. The ability to move the marking head of the laser scanner/marking system relative to the marked object may eliminate the need for the stage of the system through which the object passes to be movable, thus reducing the mechanical complexity of the system compared to some prior systems.

Aspects and embodiments of the laser scanner/marking system disclosed herein may be installed in production systems where existing laser scanner/marking systems cannot be installed. The cylindrical shape of the housing 125 may make it easier for the housing 125 to clamp in place to a piece of manufacturing equipment than a housing having a rectangular cross-section. The flexible umbilical cord allows the housing containing the drive mechanism and associated mirrors to be separated from the bulky laser generating equipment, further increasing the installation flexibility of the disclosed laser scanner/marking system. In some cases, for example, a laser marking head including housing 125 may be retrofitted into systems that previously utilized continuous inkjet marking heads of similar dimensions. Retrofitting a system to include laser marking heads, rather than continuous inkjet marking heads, can reduce the cost of ownership of the system by, for example, eliminating the need to purchase ink consumables throughout the life of the system. Further, the laser marking system may operate faster than the continuous inkjet system for marking a digital or two-dimensional code onto an object, and thus, retrofitting the marking system by replacing the continuous inkjet marking head with a laser marking system that includes the laser marking head disclosed herein may improve the operating speed and throughput of the marking system.

In additional embodiments, instead of outputting a laser beam, the systems disclosed herein may be used to receive optical signals from directions defined by the positions of mirrors 100A and 100B. For example, instead of being used to direct light out of the housing 125 containing the drive mechanism A, B and associated mirrors, the mirrors 115 may be used to receive optical signals from outside the housing 125 through apertures in the housing 125. Light may be directed from mirror 115 to mirror 100A, then mirror "b", then mirror "a", then mirror 100A, then mirror 110, and up the interior of housing 125 and/or through an optical waveguide onto an optical sensor, such as included in a video camera. Alternatively, the mirror 100A may be formed of a material transparent or translucent to the light frequency of interest, and a camera chip may be provided on the rear of the mirror 100A to receive the optical signal from the mirror "a".

Example (c):

laser marking heads were constructed as functional prototypes using CTI and Citizen galvanometers and a 630 nm red laser beam source to form cylindrical marking heads with a diameter of approximately 40 mm.

Fig. 15 shows a side view of an electromagnetic radiation steering mechanism including electromagnetic radiation manipulators "a", "b" according to an embodiment of the present invention. The electromagnetic radiation steering mechanism includes a first optical element 100A having an associated first actuator a configured to rotate the first optical element 100A about a first axis of rotation 160 to change a first coordinate of a first steering axis (e.g., the limits of steering movement of sample rays 105A-D shown in fig. 10 and 11) in a two-dimensional field of view. The electromagnetic radiation steering mechanism further includes a second optical element 100B having an associated second actuator B configured to rotate the second optical element 100B about a second axis of rotation 170 to change a second coordinate of a second steering axis in the two-dimensional field of view 105A-D (e.g., the limits of steering movement of the sample rays 105A-D shown in FIGS. 10 and 11). In the example of fig. 15, the first optical element 100A is adjacent to the second optical element 100B. In the example of fig. 15, the first optical element 100A is offset from the second optical element 100B along an axis that is substantially parallel to the first and second axes of rotation 160, 170. In the example of fig. 15, the first optical element 100A includes a first reflective surface configured to receive and reflect electromagnetic radiation 105, and the second optical element 100B includes a second reflective surface configured to receive and reflect electromagnetic radiation 105. In the example of fig. 15, the first rotation axis 160 and the first reflective surface are substantially parallel, and the second rotation axis 170 and the second reflective surface are substantially parallel.

The electromagnetic radiation steering mechanism further includes an electromagnetic radiation manipulator "a", "B" optically disposed between the first and second optical elements 100A, 100B. The first optical element 100A is configured to receive electromagnetic radiation 105 and direct the electromagnetic radiation 105 to the electromagnetic radiation manipulators "a", "b". The electromagnetic radiation manipulators "a", "B" are configured to direct electromagnetic radiation 105 to the second optical element 100B. The second optical element 100B may be configured to direct electromagnetic radiation 105 to an optical output of the electromagnetic radiation steering mechanism. The second optical element 100B may, for example, be configured to direct electromagnetic radiation 105 to an optical input of an optical device (not shown), such as a camera, configured to receive the diverted electromagnetic radiation.

In the example of fig. 15, the electromagnetic radiation manipulator includes a first mirror "a" and a second mirror "b". First mirror "a" is configured to receive electromagnetic radiation 105 after electromagnetic radiation 105 has interacted with first optical element 100A, and direct electromagnetic radiation 105 to second mirror "b". Second mirror "B" is configured to receive electromagnetic radiation 105 after electromagnetic radiation 105 has interacted with first mirror "a" and direct electromagnetic radiation 105 to second optical element 100B. The first mirror "a" and the second mirror "b" are fixed with respect to each other.

The first mirror "a" is arranged to impose an approximately 90 ° variation in the direction of propagation of the electromagnetic radiation 105. To accomplish this, first mirror "a" may be optically disposed at a 45 angle relative to incident electromagnetic radiation 105. Second mirror "b" is arranged to impose an approximately 90 ° change in the direction of propagation of electromagnetic radiation 105. To accomplish this, the second mirror "b" may be optically disposed at a 45 ° angle relative to the incident electromagnetic radiation 105. These changes in the propagation direction of electromagnetic radiation 105 enable two orthogonal degrees of freedom of beam deflection, as illustrated by sample rays 105A, 105B, 105C, and 105D in fig. 10 and 11.

A first angle is defined between the first and second rotational axes 160, 170 and a second angle is defined between the first and second steering axes. The electromagnetic radiation manipulators "a", "b" are configured to introduce a difference between the first angle and the second angle. In the example of fig. 15, the first axis of rotation 160 and the second axis of rotation 170 are non-orthogonal. In the example of fig. 15, the first axis of rotation 160 and the second axis of rotation 170 are substantially parallel. In the example of fig. 15, the first steering axis and the second steering axis are substantially orthogonal. That is, in the example of fig. 15, the electromagnetic radiation manipulators "a", "b" are configured to introduce a difference of about 90 ° between the first angle and the second angle.

Fig. 16 shows a side view of the electromagnetic radiation steering mechanism of fig. 15, further including a third reflector 110 in accordance with an embodiment of the present invention. The electromagnetic radiation 105 is redirected 90 by the third reflector 110 to hit the first optical element 100A of the first actuator a. This is useful in the formation of coaxial devices, where electromagnetic radiation 105 generally propagates in a direction parallel to the first and second axes of rotation of first and second optical elements 100A, 100B (e.g., as the electromagnetic radiation enters and exits the electromagnetic radiation steering mechanism). It will be appreciated that at various locations within the electromagnetic radiation steering mechanism, the electromagnetic radiation propagates in directions that do not follow an axis parallel to the first and second axes of rotation. However, the electromagnetic radiation manipulator advantageously causes the first and second axes of rotation to be parallel to each other, and as discussed in more detail below with reference to fig. 16 and 17, other optical elements (e.g., reflectors) may be introduced to allow electromagnetic radiation to enter and exit the electromagnetic radiation steering mechanism along an axis parallel to the first and second axes of rotation.

Fig. 17 shows a side view of the electromagnetic radiation steering mechanism of fig. 15, further including a fourth reflector 115 according to an embodiment of the present invention. After electromagnetic radiation 105 has been reflected from second optical element 100B, electromagnetic radiation 105 is redirected 90 by fourth reflector 115. The electromagnetic radiation 105 may then exit the electromagnetic radiation steering mechanism and be incident on an object (e.g., a product to be marked by the electromagnetic radiation 105).

Fig. 18 shows a side view of the electromagnetic radiation steering mechanism of fig. 16, further including a collimator 200 and focusing optics 210, 220 in accordance with an embodiment of the present invention. Collimator 200 may be configured to receive electromagnetic radiation 105 from a radiation source or an optical fiber (not shown) and provide a beam of electromagnetic radiation 105 having substantially parallel rays. The focusing optics 210, 220 may be configured to receive the electromagnetic radiation 105 provided by the collimator 200 and to condition the electromagnetic radiation 105 in a desired manner, for example, to ensure that the electromagnetic radiation 105 fits the first and second optical elements 100A, 100B.

Fig. 19 illustrates a side view of a marking head 500 of a laser marking system including an electromagnetic radiation steering mechanism according to an embodiment of the present invention. Marking head 500 includes a cylindrical housing 300. The cylindrical housing 300 may, for example, have a diameter of about 40 mm and a length of about 350 mm. The cylindrical housing 300 may have dimensions substantially similar to the print head of a model 1860 continuous inkjet printer available from Videojet Technologies, inc. Heading head 500 may, for example, have a weight of about 0.5 kg or less.

The first and second axes of rotation are substantially parallel, and the electromagnetic radiation steering mechanism is mounted substantially parallel to the length of the marking head 500 of the laser marking system such that an axis 180 of the marking head 500 that is parallel to the length of the marking head 500 (i.e., the largest of the three dimensions) is substantially parallel to the first and second axes of rotation of the first and second optical elements 100A, 100B.

Fig. 20 is a side view of the heading head 500 of fig. 19, the heading head further including a flexible umbilical 400 according to an embodiment of the present invention. Flexible umbilical 400 is configured to connect to heading head 500 and transmit power and/or control signals to heading head 500 from another object (e.g., a controller). Flexible umbilical 400 may advantageously allow for easy movement of heading head 500, further increasing the range of applications and installation environments in which heading head 500 may be used.

For example, electromagnetic radiation 105 may have a beam diameter of about 2.5 mm when exiting flexible umbilical 400 and entering an electromagnetic radiation steering mechanism. The marking head 500 may be capable of marking a product, for example, at a rate of about 1700 characters per second. The characters may have a height of about 2 mm. When used to mark a product, the electromagnetic radiation 105 exiting the marking head 500 may have a beam diameter between about 200 μm and about 300 μm. When used to carve a product, the electromagnetic radiation 105 exiting the marking head 500 may have a beam diameter between about 10 μm and about 15 μm.

Electromagnetic radiation 105 may be generated by a radiation source (such as, for example, CO)₂A laser or a diode laser) is provided to the umbilical assembly 400. Umbilicus assembly 400 can be connected to housing 300 of heading head 500. The optical fibers of the umbilical assembly 400 may direct the radiation 105 to the collimator 200 in the heading head 500. The collimator 200 may condition the radiation 105 in a desired manner and then direct the radiation 105 to focusing optics 210 for further conditioning as needed. Radiation 105 may then be incident on third reflector 110, third reflector 110 being configured to reflect radiation 105 and thereby change the propagation direction of radiation 105 by 90 ° towards first optical element 100A. The first optical element 100A may reflect radiation towards a first mirror "a" of the electromagnetic radiation manipulator. A first mirror "a" may reflect radiation 105 and thereby change the direction of propagation of radiation 105 by 90 ° towards a second mirror "b" of the electromagnetic radiation manipulator. Second mirror "B" may reflect radiation 105 and thereby change the propagation direction of radiation 105 by 90 ° toward second optical element 100B. The second optical element 100B may reflect radiation toward the fourth reflector 115. Fourth reflector 115 may reflect radiation 105 and thereby change the direction of propagation of radiation 105 by 90 ° toward the output of headed head 500.

The electromagnetic radiation manipulators "a", "B" enable the parallel optical elements 100A, 100B to steer radiation along non-parallel (e.g., perpendicular) axes. Having parallel optical elements 100A, 100B (and associated actuator A, B) allows the electromagnetic radiation steering mechanism to be mounted within the heading head 500 such that the two axes of rotation of the first and second optical elements are parallel to the length or major axis 180 of the heading head 500. This greatly reduces the size and weight of heading head 500 relative to known heading heads. Thus, the marking head 500 described herein may be easier to install and allow greater flexibility of use (e.g., movement during marking and/or positioning the marking head in a small space) than known marking heads.

Fig. 21A and 21B illustrate an embodiment of the variable optical path length device 301 in a plan view and a perspective view, respectively. The variable optical path length device may be housed in a marking head together with the electromagnetic radiation diverting mechanism. The light beam 305 is shown entering the device through a first lens 310. The beam 305 may be received from a laser source along an optical fiber or may be generated within the marking head itself. The first lens 310 may have a diameter of, for example, about 10 mm. After passing through the first lens 310, the light beam 305 impinges on a first optical element 315, e.g., a first one of a pair of movable mirrors 315, 320. The light beam 305 is reflected from the reflective surface 315a of the first movable mirror 315 onto the reflective surface 320a of the second mirror 320 of the pair of movable mirrors 315, 320. The pair of movable mirrors 315, 320 are mounted to a spin base 325, and the spin base 325 is rotatable about an axis normal to the surface of the spin base 325. The axis of the rotating base passes through the center point 302 between the pair of movable mirrors 315, 320.

A rotary actuator (e.g., a galvanometer motor) may be used to rotate the rotating base 325 and the pair of moveable mirrors 315, 320 as desired.

The light beam 305 is reflected from the reflective surface 320a of the second movable mirror 320 onto a corner reflector 330, which corner reflector 330 may comprise a pair of perpendicular mirrors 330a, 330b (or alternatively a reflective prism with perpendicular reflective facets). The light beam 305 is reflected back from the corner reflector 330 in the opposite direction that it entered the corner reflector 330 and impinges back on the reflective surface 320a of the second movable mirror 320. The light beam 305, after reflecting back from the corner reflector 330, impinges on the second movable mirror 320 at a different vertical position than the position at which the light beam impinges on the second movable mirror 320 after being directed by the first movable mirror 315 to the second movable mirror 320. The difference in vertical position is related to the vertical distance between the portions of the mirrors 330a, 330b of the corner reflector 330 that reflect the light beam 305. The light beam 305 is reflected from the reflective surface 320a of the second movable mirror 320 back to the reflective surface 315a of the first movable mirror 315. The light beam 305, after reflecting off the second movable mirror 320, impinges on the first movable mirror 315 at a different vertical position than the position at which the light beam impinges on the first movable mirror 315 from the first lens 310. The light beam 305 is then reflected from the reflective surface 315a of the first movable mirror 315 onto the reflective surface 335a of the output mirror 335. The output mirror 335 is vertically displaced from the first lens 310. The light beam 305 reflects from the output mirror 335 through a second lens 340, the second lens 340 also being referred to as an output lens. The second lens 340 is vertically displaced with respect to the first lens 310. The light beam passes through the second lens 340 and comes out of the variable optical path length apparatus 100. The second lens 340 may have a diameter of, for example, about 20 mm.

Of course, suitable optical components (e.g., mirrors, lenses, etc.) may be provided as desired to direct the beam from the collimator to the input lens 310, and then from the output lens 340 toward components of the electromagnetic radiation turning mechanism (e.g., the third reflector 110 or the first optical component 100A).

Each of the mirrors in the variable optical path length device 100 and the reflective surface of the corner reflector 330 may be planar. One or both of the lenses 310, 340 may have one or both surfaces that are concave, convex, or planar (flat), or one of the lenses 310, 340 may have one or both surfaces with a different curvature than the other lens 310, 340.

The first and second lenses 310, 340 may be made of a material (e.g., BK7 borosilicate glass, quartz, ZnSe, or Ge) capable of refracting the optical beam 305 at the operating frequency of the optical beam, and may have an anti-reflective coating that is characteristic of the wavelength of the optical beam 305. The mirrors may be similar to those of the electromagnetic radiation steering mechanism.

The mirrors 315, 320 may be collectively referred to as a rotatable path length adjuster 360 along with the base 325. It will be appreciated that the relationship between the focal length and the orientation of the rotatable path length adjuster 360 will depend on the optical power of the input and output lenses, as well as the geometry of the rotatable path length adjuster 360, and other components of the variable optical path length assembly 100. For example, by increasing the distance of the mirror from the axis of rotation, the change in geometric path length for a given change in rotation will also increase.

In a more general case, the corner reflector 330 may be referred to as a fixed optical element. It will be appreciated that, unlike the mirrors 315, 320, the corner reflector 330 is fixed in position relative to the axis of rotation of the rotatable path length adjuster 360.

It will be understood that in the general case, the rotatable path length adjuster 360 may be considered to receive the radiation beam along the input path (i.e. from the input lens 310). Rotatable path length adjuster 360 may also be understood as directing the beam of radiation along a first intermediate path between mirror 320 and angled mirror 330 (e.g., having first been directed to mirror 320 by mirror 315).

Accordingly, the corner reflector 330 may be considered to receive the radiation beam directed by the rotatable path length adjuster along a first intermediate path and to direct the radiation beam back to the rotatable path length adjuster along a second intermediate path.

The rotatable path length adjuster 360 may then be considered to receive the beam of radiation along a second intermediate path (i.e. from the angled mirror 330 to the mirror 320). Finally, once the beam of radiation has been directed by mirror 320 back to mirror 315, the rotatable path length adjuster may ultimately be understood to direct the beam of radiation along an output path (i.e., from mirror 315 toward mirror 335). The path from first mirror 315 to second mirror 320 may be referred to as a third intermediate path. The path from the second mirror 320 to the first mirror 315 may be referred to as a fourth intermediate path. Mirrors 315, 320 may be referred to as first and second optical components, respectively. In other embodiments, the functions of the first and second optical components may be provided by other optical components.

It will be appreciated that as the rotatable path length adjuster 360 rotates in a clockwise direction about the axis 302, the physical distance between the input lens 310 and the first mirror 315 will decrease. Similarly, when rotatable path length adjuster 360 is rotated in a clockwise direction about axis 302, the physical distance between second mirror 320 and corner reflector 330 will decrease. On the other hand, when the rotatable path length adjuster is rotated in a clockwise direction, the path between the mirrors 315, 320 will become more inclined, and therefore longer. However, the change in increased path length will be greater than the offset of the decreased path length, resulting in a decrease in the overall geometric path length (and optical path length) between the input lens and the output lens. It will be appreciated that there will be a predictable and continuously variable (although not necessarily linear) relationship between the angular position of the rotatable path length adjuster 360 and the geometric path length between the input and output. However, as the angular position of the rotatable path-length adjuster 360 changes, the direction of the output path will not change (although the starting position will change). Thus, the input and output positions are fixed relative to the position of axis 302 and corner reflector 330. In this way, the beam can be directed into and out of the path length adjuster by fixed optics, and the path length is varied in order to vary the focal length of the output beam.

Having thus described several aspects of at least one embodiment, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the disclosure. The acts of the methods disclosed herein may be performed in an order different than illustrated, and one or more acts may be omitted, substituted or added. One or more features of any of the examples disclosed herein may be combined with or substituted for one or more features of any of the other examples disclosed. Accordingly, the foregoing description and drawings are by way of example only.

The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. As used herein, the term "plurality" refers to two or more items or components. As used herein, dimensions described as "substantially" similar may be considered to be within about 25% of each other. The terms "comprising," including, "" carrying, "" having, "" including, "and" involving "are open-ended terms, whether in the written description or the claims, etc., that is, to mean" including, but not limited to. Thus, use of such terms is intended to encompass the items listed thereafter and equivalents thereof as well as additional items. The transition phrases "consisting of …" and "consisting essentially of …" in reference to the claims are closed or semi-closed transition phrases, respectively. Use of ordinal terms such as "first," "second," "third," etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

The electromagnetic radiation steering mechanism may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic and/or other types of optical components, or any combination thereof, for directing, shaping, and/or controlling electromagnetic radiation.

Although specific reference may be made in this text to the use of electromagnetic radiation steering mechanisms in the marking of products, it should be understood that the electromagnetic radiation steering mechanisms described herein may have other applications. Possible other applications include laser systems for engraving products, optical scanners, radiation detection systems, medical devices, electromagnetic radiation detectors, such as cameras or time-of-flight sensors, where radiation may exit and re-enter the sensor, and the like.

While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. The above description is intended to be illustrative, and not restrictive. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.