阅读说明：本技术 光学器件、包括其的投射装置及直线投射方法 (Optical device, projection apparatus including the same, and linear projection method ) 是由 王燚言 陈鹏 于 2020-05-12 设计创作，主要内容包括：本发明提供了一种包括衍射光学元件和柱状微透镜阵列的光学器件,所述衍射光学元件具有微结构面,所述微结构面上设置有多个微结构图案单元,所述微结构图案单元配置成可将入射到所述衍射光学元件上的光束进行调制,并投射出直线状的点阵；所述柱状微透镜阵列配置成将所述点阵中的点沿点阵的延伸方向展宽以投射出连续直线。本发明还提供一种包括该光学器件的直线投射装置以及使用该装置投射直线的方法。(The invention provides an optical device comprising a diffractive optical element and a columnar microlens array, wherein the diffractive optical element is provided with a microstructure surface, a plurality of microstructure pattern units are arranged on the microstructure surface, and the microstructure pattern units are configured to modulate light beams incident on the diffractive optical element and project linear lattices; the columnar microlens array is configured to widen points in the lattice in an extending direction of the lattice to project a continuous straight line. The invention also provides a straight line projection device comprising the optical device and a method for projecting a straight line by using the device.)

1. An optical device for projecting a straight line, comprising:

a diffractive optical element having a microstructure surface on which a plurality of microstructure pattern units are disposed, the microstructure pattern units being configured to modulate a light beam incident on the diffractive optical element and project a linear lattice;

a columnar microlens array configured to widen dots in the lattice in an extending direction of the lattice to project a continuous straight line.

2. The optical device of claim 1, wherein the cylindrical microlens array is disposed downstream of the diffractive optical element.

3. The optical device of claim 1, wherein the microstructured surface of the diffractive optical element comprises a first area comprising a plurality of first microstructure pattern units and a second area comprising a plurality of second microstructure pattern units, wherein the first microstructure pattern units are configured to modulate and project a light beam incident on the diffractive optical element out of a first lattice of a first direction and the second microstructure pattern units are configured to modulate and project a light beam incident on the diffractive optical element out of a second lattice of a second direction, wherein the first direction is perpendicular to the second direction,

the columnar microlens array comprises a third area and a fourth area, the third area comprises a first columnar microlens array, the fourth area comprises a second columnar microlens array, the first area corresponds to the third area, the second area corresponds to the fourth area, the first columnar microlens array is configured to widen the points in the first lattice along the extending direction of the first lattice to form a continuous straight line, and the second columnar microlens array is configured to widen the points in the second lattice along the extending direction of the second lattice to form a continuous straight line.

4. An optical device as claimed in any one of claims 1 to 3, wherein the diffractive optical element has a substrate, the microstructure face being on one side of the substrate, the lenticular microlens array being on the opposite side of the substrate to the microstructure face.

5. The optical device of any one of claims 1 to 3, wherein the columnar microlens array is configured to widen adjacent dots in the lattice into mutually adjoining but non-coincident line segments.

6. The optical device according to any one of claims 1 to 3, wherein the diffractive optical element is a one-dimensional grating designed for collimated light, and an angle between a widening direction of the lenticular microlens array and an extending direction of the lattice is smaller than a preset value.

7. The optical device of any one of claims 1 to 3, wherein the field of view of the lenticular microlens array matches the angular spacing of the diffractive optical elements.

8. A linear projection device, comprising:

a light source configured to project a light beam;

the optical device for projecting straight lines according to any one of claims 1 to 7, said optical device being located in the optical path downstream of said light source and receiving the light beam projected by said light source, projecting a continuous straight line.

9. A method for projecting a straight line, comprising:

emitting a light beam by a light source;

receiving the light beam and projecting a linear lattice through a diffractive optical element;

and receiving the lattice through a columnar microlens array, and widening the lattice to project continuous straight lines.

10. The method of claim 9, wherein the method is implemented by the linear projection device of claim 8.

Technical Field

The present invention relates generally to the field of optical technology, and more particularly, to an optical device for projecting a straight line, a projection apparatus including the optical device, and a method of projecting a straight line using the apparatus.

Background

The laser demarcation device is widely applied to the building construction industry and is used for projecting a laser reference line so as to improve the construction precision. The laser projector commonly used in the market at present has a word line and a cross line, and the realization method comprises the following steps: the diverging light from a laser diode is usually collimated and then passed through a Refractive Optical Element (ROE), such as a cylindrical lens, to form the desired optical field (reference line). However, the existing laser line projector using the refraction optical element to realize the cross line has the problems that the two cylindrical lenses are difficult to vertically align, the installation difficulty is high, and the shock resistance is poor.

An alternative is to project the reticle as a whole by means of a Diffractive Optical Element (DOE). However, designing a large field-of-view reticle DOE also presents some technical problems: when a single DOE is designed to project a continuous cross line with a large field of view, due to the interference effect of laser as a projection light source, dispersed light spots can be formed on the continuous line, and the attractiveness of the cross line is affected.

Disclosure of Invention

In view of at least one of the drawbacks of the prior art, the present invention provides an optical device for projecting a straight line, comprising:

a diffractive optical element having a microstructure surface on which a plurality of microstructure pattern units are disposed, the microstructure pattern units being configured to modulate a light beam incident on the diffractive optical element and project a linear lattice;

a columnar microlens array configured to widen dots in the lattice in an extending direction of the lattice to project a continuous straight line.

According to an aspect of the invention, the lenticular microlens array is disposed downstream of the diffractive optical element.

According to an aspect of the present invention, the microstructure surface of the diffractive optical element includes a first region including a plurality of first microstructure pattern units and a second region including a plurality of second microstructure pattern units, wherein the first microstructure pattern units are configured to modulate a light beam incident on the diffractive optical element and project a first lattice in a first direction, and the second microstructure pattern units are configured to modulate a light beam incident on the diffractive optical element and project a second lattice in a second direction, wherein the first direction is perpendicular to the second direction,

the columnar microlens array comprises a third area and a fourth area, the third area comprises a first columnar microlens array, the fourth area comprises a second columnar microlens array, the first area corresponds to the third area, the second area corresponds to the fourth area, the first columnar microlens array is configured to widen the points in the first lattice along the extending direction of the first lattice to form a continuous straight line, and the second columnar microlens array is configured to widen the points in the second lattice along the extending direction of the second lattice to form a continuous straight line.

According to an aspect of the present invention, the diffractive optical element has a substrate, the microstructure surface is on one side of the substrate, and the lenticular microlens array is on the opposite side of the substrate from the microstructure surface.

According to one aspect of the invention, wherein the lenticular microlens array is configured to widen adjacent dots in the lattice into mutually adjoining but non-overlapping line segments.

According to one aspect of the invention, the diffractive optical element is a one-dimensional grating designed for collimated light, and an included angle between a widening direction of the columnar microlens array and an extending direction of the lattice is smaller than a preset value.

According to an aspect of the invention, wherein the field of view of the lenticular microlens array matches the angular pitch of the diffractive optical elements.

The present invention also provides a linear projection apparatus, comprising:

a light source configured to project a light beam;

the optical device for projecting straight lines is located in the optical path downstream of the light source, receives the light beams projected by the light source, and projects continuous straight lines.

The invention also relates to a method for projecting a straight line, comprising:

emitting a light beam by a light source;

receiving the light beam and projecting a linear lattice through a diffractive optical element;

and receiving the lattice through a columnar microlens array, and widening the lattice to project continuous straight lines.

According to another aspect of the invention, the method is carried out by a linear projection device as described above.

The optical device comprises a diffractive optical element and a columnar micro-lens array, wherein the diffractive optical element can modulate incident light into a linear lattice, the columnar micro-lens array can widen the linear lattice into continuous straight lines, and a clear and attractive cross line with a large field of view can be projected by arranging a plurality of micro-structure pattern units on the diffractive optical element, so that the optical device is convenient for engineering application and solves the problems of difficulty in vertical alignment, high installation difficulty and poor impact resistance of two columnar lenses. The invention also provides a straight line projection device comprising the optical device and a method for projecting a straight line by using the device.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 shows a reticle projected by a single microstructure pattern unit and a partial magnified view thereof;

FIG. 2 schematically illustrates an optical device according to a preferred embodiment of the present invention;

FIG. 3A shows the lattice projected after modulation by a diffractive optical element;

FIG. 3B shows a continuous straight line formed after the cylindrical microlens array is widened;

fig. 4 schematically shows an arrangement of a plurality of microstructure pattern units, a columnar microlens array, of a diffractive optical element according to a preferred embodiment of the present invention;

FIG. 5 schematically illustrates an optical device according to a preferred embodiment of the present invention;

fig. 6A schematically shows the projected line width in an ideal state;

FIG. 6B schematically shows the variation of the projected line width caused by the alignment error of the lenticular microlens array with the diffractive optical element;

FIG. 7 shows a graph of alignment error tolerance versus lenticular lenslet array field angle;

fig. 8 shows a cylindrical microlens array example of a 5 ° field angle;

FIG. 9 schematically illustrates a large field of view reticle projected by an optical device in accordance with a preferred embodiment of the present invention;

FIG. 10 schematically illustrates a linear projection device according to a preferred embodiment of the present invention;

fig. 11 illustrates a method of projecting a straight line according to a preferred embodiment of the present invention.

Detailed Description

In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection, either mechanically, electrically, or in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly above and obliquely above the second feature, or simply meaning that the first feature is at a lesser level than the second feature.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.

The embodiments of the present invention will be described in conjunction with the accompanying drawings, and it should be understood that the embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

The laser has high coherence, so the target pattern formed by the projection of the diffractive optical element has a relatively obvious speckle effect, and for the design of the reference line of the laser line projector, the line has irregular granular dark spots and is not beautiful enough, as shown in fig. 1. In fig. 1, the left side shows the cross lines projected by the single microstructure pattern unit of the diffractive optical element, and the right side is a partially enlarged pattern of the cross lines, wherein a large number of irregular granular dark spots can be seen, and the reference line is not clear and beautiful. To address this problem, preferred embodiments of the present invention provide an optical device that combines a plurality of microstructure units of a diffractive optical element with a cylindrical microlens array.

As shown in fig. 2, the present invention provides an optical device 10 for projecting straight lines, according to a preferred embodiment of the present invention, including a diffractive optical element 12 and a cylindrical microlens array 13. The diffractive optical element 12 has a microstructure surface 121, and a plurality of microstructure pattern units are provided on the microstructure surface 121. The microstructure pattern units on the microstructure surface 121 can modulate the light beam incident on the diffractive optical element 12 and project a linear lattice. The lenticular microlens array 13 may widen the dots in the lattice in the extending direction of the lattice to project a continuous straight line.

According to a preferred embodiment of the invention, a lenticular microlens array 13 is arranged in the optical path downstream of the diffractive optical element 12, the lenticular microlens array 13 thus receiving the lattice projected after modulation by the diffractive optical element 12 and widening each point of the lattice, in particular along the extension of the lattice, so as to project a continuous straight line. Fig. 3A shows the lattice of the projected light modulated by the diffractive optical element 12, and fig. 3B shows the continuous straight lines formed by widening the columnar microlens array 13.

Fig. 4 shows the surface configuration of the diffractive optical element 12 and the surface configuration of the lenticular microlens array 13, which can be used to project a reticle, according to a preferred embodiment of the present invention. As shown in fig. 4, the diffractive optical element 12 has a microstructure surface 121, and a plurality of microstructure pattern units are provided on the microstructure surface 121. As shown, the microstructure surface 121 includes a first region 1211 and a second region 1212, and the first region 1211 includes a one-dimensional diffraction grating periodically arranged in the vertical direction, and can modulate a light beam incident on the diffractive optical element 12 and project a linear lattice in the vertical direction. The second region 1212 includes one-dimensional diffraction gratings periodically arranged in the horizontal direction, and modulates the light beam incident on the diffractive optical element 12 and projects a linear lattice in the horizontal direction. The circular area 1213 in the figure is the incident spot of the laser beam. The region 1213 of the incident light spot covers both the first region 1211 and the second region 1212, which modulate the incident light to project a horizontal lattice and a vertical lattice, respectively.

The lenticular microlens array 13 includes a fourth region 131 and a third region 132, and the fourth region 131 includes a lenticular microlens array in the horizontal direction, that is, a plurality of lenticular microlenses whose axes are in the vertical direction are arranged in the horizontal direction. The third region 132 includes a columnar microlens array in the vertical direction, i.e., a plurality of columnar microlenses are arranged in the vertical direction, the axes of the plurality of columnar microlenses being in the horizontal direction. The fourth region 131 of the lenticular microlens array 13 corresponds to the second region 1212 of the diffractive optical element 12, and receives the horizontal lattice modulated by the diffraction grating on the second region 1212, and widens it in the horizontal direction, that is, widens a linear lattice in the horizontal direction to form a continuous straight line. The third region 132 of the lenticular microlens array 13 corresponds to the first region 1211 of the diffractive optical element 12, receives the vertical lattice modulated by the diffraction grating on the first region 1211, and widens it in the vertical direction, that is, widens a linear lattice in the vertical direction to form a continuous straight line. Circular region 133 is the incident light field of the laser beam.

The diffractive optical element 12 shown in fig. 4, in which the first region 1211 of the microstructure surface 121 is on the left side in the figure, the second region 1212 is on the right side in the figure, the fourth region 131 of the cylindrical microlens array 13 is on the left side in the figure, and the third region 132 is on the right side in the figure, it is easy for a person skilled in the art to think that the left and right positions in the figure are exchanged, or the first region 1211, the second region 1212 of the microstructure surface 121, the fourth region 131 of the cylindrical microlens array 13, and the third region 132 are disposed at different positions of the optical device 10, and the same technical effect can be achieved without changing the corresponding relationship between the diffractive optical element 12 and the cylindrical microlens array 13, and all the equivalents belonging to the technical means belong to the protection scope of the present invention.

According to a preferred embodiment of the present invention, an optical device 10 is shown in fig. 2, in which a diffractive optical element 12 has a substrate, a microstructure face 121 is located on one side of the substrate, and a lenticular microlens array 13 is located on the opposite side of the substrate from the microstructure face 121. Since the optical path is reversible, if the laser beam is set to pass through the cylindrical microlens array 13 and then pass through the diffractive optical element 12, a continuous straight line can be generated as well. Therefore, as shown in the combination of fig. 5, the cylindrical microlens array 13 is located "below" (in the position relationship shown in the figure) the diffractive optical element 12, and the laser beam emitted from the light source passes through the cylindrical microlens array 13 and then the diffractive optical element 12, so that substantially the same technical effect can be achieved. Combinations such as those shown in fig. 5 are also within the scope of the present invention. In addition, by processing the microstructure surface 121 of the diffractive optical element 12 and the lenticular microlens array 13 on the same substrate, the processing and manufacturing and mounting are greatly facilitated. For example, the relative positional relationship between the microstructure surface 121 and the lenticular microlens array 13, such as the relative distance along the optical axis direction and the angular relationship therebetween, can be ensured during the processing. Especially the angular relationship between the two, has an important influence on the line width of the finally projected straight line, which will be described in detail below.

According to a preferred embodiment of the present invention, such as the optical device 10 shown in fig. 2, the lenticular microlens array 13 is configured to widen adjacent dots in the lattice into line segments that are mutually adjacent but do not coincide. If the line segments overlap each other too much, the brightness of the projected straight line becomes uneven, and further, water ripples are generated at the overlapping portion due to light interference.

According to a preferred embodiment of the present invention, the diffractive optical element 12 shown in fig. 4 has the microstructure surface 121, the microstructure surface 121 includes a first region 1211 and a second region 1212, the first region 1211 includes the diffraction grating periodically arranged in the vertical direction, and the second region 1212 includes the diffraction grating periodically arranged in the horizontal direction, that is, the diffractive optical element 12 is a one-dimensional grating. One skilled in the art will readily appreciate that one-dimensional gratings may be replaced with two-dimensional gratings. For example, the diffractive optical element 12 includes a plurality of microstructure pattern units that are periodically arranged in a two-dimensional array, wherein each microstructure pattern unit has the same phase distribution pattern. Each microstructure pattern unit on the diffractive optical element 12 is capable of changing the phase distribution of the wave surface of light incident thereon, thereby modulating the transmission of light such that the output light beam conforms to a preset light intensity distribution and light field pattern. In the invention, the phase distribution of each microstructure pattern unit is configured to receive laser and modulate the laser to project a linear lattice. Therefore, a solution in which the diffractive optical element 12 is a two-dimensional grating is also within the scope of the present invention.

According to a preferred embodiment of the present invention, the diffractive optical element 12 is designed for collimating light, and thus a collimating lens needs to be disposed between the laser light source and the optical device 10 in order to shape the laser light emitted from the laser light source into collimated light. Those skilled in the art will readily appreciate that the scope of the present invention is not so limited. For example, the laser light source may be a divergent light source, the diffractive optical element 12 is designed for the divergent light source, for example, a fresnel diffractive lens similar to a collimating lens in function may be designed and a phase distribution pattern may be obtained, a diffractive optical element for collimated light may be designed and a corresponding phase distribution pattern may be obtained, and then the two phase patterns may be superimposed.

The straight line projected through the optical device 10 in the ideal case, i.e., when the diffractive optical element 12 and the lenticular microlens array 13 are perfectly aligned (the angular deviation between them is 0 °), is shown in fig. 6A. In this case, the line width of the projected straight line can be very small. However, in practical cases, the cylindrical microlens array 13 cannot generally widen the light beam modulated by the diffractive optical element 12 in a strictly horizontal direction and a strictly vertical direction due to the alignment problem of the cylindrical microlenses, and the widening direction forms an angle with the extending direction of the lattice, such as the angle θ shown in fig. 6B. In this case, the angle caused by the alignment error, it appears that the straight line will have a certain width, w as shown in fig. 6B. Therefore, during the design and manufacture of the optical device 10, the alignment error tolerance of the lenticular microlens array 13 and the diffractive optical element 12, i.e., the angle θ, can be deduced inversely according to the line width value of the straight line allowed in the actual use scene, and the angle between the widening direction of the lenticular microlens array 13 and the extending direction of the lattice is ensured to be smaller than the angle θ during the design and manufacture.

When the field angle β of the lenticular microlens array 13 is small, the length of the line segment widened by the lenticular microlens array can be approximately represented by L β, where L is the working distance and β is expressed in radians, and further the above-mentioned alignment error tolerance, i.e., the angle θ, can be approximately equal to w/(L β). Fig. 7 shows the simulation result between the alignment error tolerance and the field angle FOV of the microlens array 13. As shown in fig. 7, when the working distance is 7m, the tolerance to the alignment error can be calculated by taking w ═ 1mm as the maximum value of the cross line width. When the field angle of the lenticular microlens array 13 is 3 °, the alignment error needs to be controlled to be within 0.15 °.

The angular pitch of the linear lattice projected by the diffractive optical element 12 is determined by the size of the period of the plurality of microstructure units on the microstructure surface 121 and the wavelength of the light source, and since the angular pitch of the diffractive optical element 12 matches the field angle of the microlens array 13 when designing the optical device according to the present invention, β is expressed by β, which can be approximately equal to λ/d according to the grating equation, where λ is the wavelength and d is the period of the microstructure units, for example: when the period of the one-dimensional grating is 6.1um and the wavelength of the light source is 532nm, the angular interval of the projected linear lattice is about 5 degrees. The field angle of the cylindrical microlens array 13 should match with the angular spacing of the linear lattice, so that the cylindrical microlens array can be widened one by one and connected into a straight line, and the water ripple effect is reduced to the maximum extent. As shown in fig. 8, the curved surface shape of the lenticular microlens determines the size of the field angle of the lenticular microlens, taking the field angle of 5 ° as an example.

FIG. 9 illustrates a large field of view reticle projected by the optics 10 shown in FIG. 2. It can be seen that the reticle projected by the optical device 10 of the present invention is clear and beautiful, has good continuity, and can overcome or mitigate the water ripple effect.

As shown in fig. 10, according to a preferred embodiment of the present invention, there is also provided a line projection apparatus 20 including: a light source 11 and optics 10. The light source 11 emits a laser beam when driven, and is incident on the optical device 10. The optical device 10 is located downstream of the light source 11 in the optical path, and receives the light beam projected by the light source 11 to project a continuous straight line.

In addition, when the diffractive optical element 12 of the optical device 10 is designed for collimated light, a collimating lens (not shown) may be disposed between the light source 11 and the optical device 10 so as to shape the laser light emitted from the light source into collimated light and then enter the optical device 10.

As shown in fig. 11, the present invention also provides a method 30 of projecting a straight line according to a preferred embodiment of the present invention, including:

in step S301, a light beam is emitted by a light source;

in step S302, receiving a light beam and projecting a linear lattice by a diffractive optical element;

in step S303, the lattice is received and expanded to project continuous straight lines by the lenticular microlens array.

The method 30, shown in fig. 11, is implemented by the linear projection device 20 in the preferred embodiment described above.

The optical device comprises a diffractive optical element and a columnar micro-lens array, wherein the diffractive optical element can modulate incident light into a linear lattice, the columnar micro-lens array can widen the linear lattice into continuous straight lines, and a clear and attractive cross line with a large field of view can be projected by arranging a plurality of micro-structure pattern units on the diffractive optical element, so that the optical device is convenient for engineering application and solves the problems of difficulty in vertical alignment, high installation difficulty and poor impact resistance of two columnar lenses. The invention also provides a straight line projection device comprising the optical device and a method for projecting a straight line by using the device.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.