阅读说明：本技术 光截面传感器和用于操作光截面传感器的方法 (Optical cross section sensor and method for operating an optical cross section sensor ) 是由 马库斯·许伦 戴维·雷德勒 托马斯·鲍尔 于 2018-07-02 设计创作，主要内容包括：光截面传感器,包括产生第一光束(2)的光学发射器(1)、将第一光束(2)改造成线形的第二光束(4)并将后者发射到监控区域中的传输光学单元(3)、具有接收光学单元的结构化接收器,接收光学单元以取决于距离的角度来捕捉位于监控区域中的漫反射对象(10)并将该对象成像到结构化光学接收器上,其中根据本发明的第二光学发射器(1a)产生第三光束(2a),第三光束(2a)经由照明光学单元(8a)照射辐射视场光阑(5),其中通过投影光学单元(8b)产生第四光束(6),视场光阑(5)将该第四光束(6)投影到监控区域中并且该第四光束(6)直接或经由分束器(9)叠加在第二光束(4)上,其中基于光束(6)来呈现应用特定的符号或信息项目,其中尤其可以标记特定兴趣区域(ROI)(7)。(Optical cross-section sensor comprising an optical transmitter (1) which generates a first light beam (2), a transmission optical unit (3) which transforms the first light beam (2) into a linear second light beam (4) and emits the latter into a monitoring area, a structured receiver with a receiving optical unit which captures a diffusely reflecting object (10) located in the monitoring area at an angle which is dependent on the distance and images the object onto the structured optical receiver, wherein the second optical transmitter (1a) according to the invention generates a third light beam (2a), the third light beam (2a) illuminates a radiation field diaphragm (5) via an illumination optical unit (8a), wherein a fourth light beam (6) is generated by a projection optical unit (8b), the field diaphragm (5) projects the fourth light beam (6) into the monitoring area and the fourth light beam (6) is superimposed on the second light beam (4) directly or via a beam splitter (9), wherein application-specific symbols or information items are presented based on the light beam (6), wherein in particular regions of interest (ROIs) can be marked (7).)

1. An optical cross-section sensor comprising an optical transmitter (1) generating a first light beam (2), a transmitting optical unit (3) transforming the first light beam (2) into a line-shaped second light beam (4) and transmitting it into a monitored area, a structured receiver comprising a receiving optical unit detecting and imaging onto the structured optical receiver a diffusely reflecting object (10) located in the monitored area at a distance-dependent angle,

It is characterized in that the preparation method is characterized in that,

There is a second optical emitter (1a) which generates a third light beam (2a), which third light beam (2a) illuminates the field stop (5) via an illumination optical unit (8a), wherein a fourth light beam (6) is generated by means of a projection optical unit (8b), which fourth light beam (6) projects the field stop (5) into the monitoring region and is superimposed to the second light beam (4) directly or via a beam splitter (9), wherein application-specific symbols or information are displayed on the basis of the light beam (6), wherein in particular regions of interest (ROI) (7) can be marked.

2. light section sensor according to claim 1, characterized in that an orientation marker for an operator is projected onto the object (10).

3. Light section sensor according to claim 1, characterized in that adjustment markings for the operator and the production are projected onto the object (10).

4. light section sensor according to claim 1, characterized in that a marker for determining the position is projected onto the object (10).

5. Light section sensor according to claim 1, characterized in that a bar graph comprising a dragged pointer is projected onto the object (10).

6. optical cross-section sensor according to claim 1, characterized in that a tolerance band is projected onto the object (10).

7. Light section sensor according to claim 1, characterized in that operating instructions are projected onto the object (10).

8. Light section sensor according to claim 1, characterized in that a predetermined height profile is projected into the monitored area and onto an object (10) located in the monitored area.

9. Method for operating a light section sensor according to one of the preceding claims, characterized in that the second optical emitter (1a) is used for projecting user information into the monitored area and thus onto an object (10) located in the monitored area, the second optical emitter (1a) providing support for an adjustment or setting process.

10. Method according to claim 9, characterized in that the ROI (7) is displayed during this process.

Technical Field

The invention relates to an optical cross-section sensor and to a method for operating an optical cross-section sensor according to claim 1 and independent claim 9.

Background

Optical sensors, in particular energy light scanners with background suppression, often also referred to as triangulation light scanners, have been widely used over the last two decades. They are used in large quantities in automation technology and are also manufactured and sold by the applicant. They have an optical transmitter which emits a light beam onto the object 1 in its monitoring area and a structured receiver comprising an image-receiving optical unit. The optical axes of the transmitting and receiving optical units are usually parallel, but depending on the measurement task they may extend at an acute angle to each other in order to satisfy the Scheimpflug condition. Preferably, the diffusely reflecting objects are detected by the receiving optical unit at an angle dependent on their distance and imaged onto the optical receiver at a position dependent on the angle of incidence (triangulation). As a receiver, all photoreceptors with spatial resolution have become a problem, with CCD chips or CMOS chips being mainly used recently.

In order to monitor the height profile, for example for object recognition on a conveyor belt, a profile sensor is used which measures the height profile along the projection laser line. These sensors are called optical cross-section sensors.

DE102012022304a1 shows a light section sensor with laser illumination, a cylindrical optical unit for generating strip-shaped illumination, and an image-receiving optical unit, and a detector array as light receiver. Furthermore, it is disclosed that the light emitted as a field stop passes through the LC display.

DE102007003024a1 shows a triangulation sensor for determining distances based on a structured illumination pattern, which is generated by means of lenses or diffractive optical elements.

as already indicated, the setting and adjustment of such sensors is not intuitive and currently provides no guidance. For example, if the user limits the area to be measured to a portion of the laser line projected onto the object, the limit is only indicated or represented indirectly via an abstract parameter. One way of providing a more user-friendly visualization is to use additional hardware, such as a computer, which is connected to the sensor and on which the measurement line with the set limits is displayed. But even here the problem is that the user has to translate the visualization into the correct position in the measurement area.

US2013/0083384a1 describes a light cross-section sensor with an optical emitter for generating a (collimated) first light beam, a transmission optical unit for transforming the first light beam into a second linear light beam, an active field stop (liquid crystal shutter array) for the second light beam, which produces a third modulated light beam from the second light beam, and a structured receiver comprising a receiving optical unit, which detects and images diffusely reflecting objects located in a monitored area at an angle dependent on the object distance onto the structured receiver.

US2016/0123893a1 describes an arrangement for measuring texture and surface structure, in which a Measurement Pattern Image (MPI) and a Result Image (RI) are projected onto a surface.

Similar arrangements are described in US2005/0068532A1 and DE102008012496A 1.

It is considered disadvantageous that information outside the measurement field and also not having wavelengths outside the spectral range producible by the (first) optical emitter cannot be projected onto the object.

disclosure of Invention

It is therefore an object of the present invention to make these sensors more user-friendly and easy to work with. It is particularly envisaged to make their setting and adjustment more efficient and perceptually more reliable.

This object is achieved by the characterizing features of claim 1 and independent claim 9. The dependent claims relate to embodiments of the invention.

the basic idea of the invention is to use a transmissive LC display, which is known per se and which according to the prior art is used as a field stop independent of the measuring beam path, as an information source for the operator, wherein any type of controllable transmissive light projector can be used instead of the LC display.

The light section sensor in question comprises, in a known manner, an optical transmitter which generates a first light beam and transmits it into the monitored area, a transmission optical unit of a second light beam which reshapes the first light beam into a line shape, and an active field stop for the second light beam, which generates a third structured light beam from the second light beam, and a structured receiver which comprises a receiving optical unit which detects and images diffusely reflecting objects located in the monitored area onto the structured optical receiver at an angle which depends on the object distance.

According to the invention, the active field stop is used for projecting visible information by projecting visible symbols into the monitored region and onto an object located in the monitored region by means of the third structured light beam, wherein the limits of a specific region of interest (ROI) ("region of interest", ROI) should be marked, defined and/or located.

In equivalent embodiments, which are advantageous only in a few cases, the active field stop can also be located directly in front of the light source.

The beam shaping transmission optical unit, which is mainly used as a line generator, is in the simplest case a cylindrical lens, but may also be a diffractive element (DOE) or a free-form lens.

In a particular embodiment, the active field stop may even be used as a single structured display element and the mounting of another graphical display is omitted, which reduces the size and manufacturing costs of the light section sensor.

Furthermore, in other embodiments, in addition to setting the current limit of the monitoring area, the operating instructions or the height profile determined during the last measuring process can also be displayed during the setting process.

For better visualization, content such as logos may be dynamically displayed. Here, variations such as inversion or blinking are conceivable.

Furthermore, overmodulation of the receiving element can be displayed and eliminated by locally and selectively adjusting the transmission of the individual sections of the line during the measurement, thereby improving the dynamic properties of the measurement.

The invention also relates to a method for operating a light section sensor, wherein an arrangement known per se is used in a novel manner to project user information into a monitored area and thus onto an object located in the monitored area.

This is advantageously done during an adjustment or setting process, wherein the currently set measuring field limit or other parameters or other information is shown to the operator without the need to perform a measuring process.

according to the invention, the optical arrangement comprises two light sources (laser/LED). They may have different wavelengths, wherein only the visible second light source may be affected by the field stop. The first light source generating the signal to be measured remains unstructured. Subsequently, the two beam paths are superimposed.

Due to their better compatibility with ambient light, PMD matrices can also be used as structured receivers without evaluating the light propagation time, wherein PMD refers to photonic mixer devices known for example from DE102012203596a 1.

Detailed Description

The invention will be explained in more detail with reference to the drawings.

Fig. 1 shows a first optical cross-section sensor according to the invention, comprising an optical emitter 1 for generating a first light beam 2, advantageously parallel. The beam modification delivery optics unit 3 generates a second linear beam 4 from the first beam 2. The second light beam 4 now passes through the beam splitter 9 and is finally projected onto the object 10. A second light source 1a, for example a laser diode, LED or LED matrix, acting as a projection light source, generates a second light beam 2 a.

The light beam 2a is now directed by the first illumination optical unit 8a onto the LC display which serves as an active field stop 5, which active field stop 5 can serve as a variable aperture for limiting purposes, but should be used primarily for the structured light beam 2 a. When using a LED matrix as light source 1a, the light beam 2a, which has not yet been modulated but may have been structured, passes through a field stop 5, an LCD display or an LCD matrix and is then imaged by a projection optical unit 8b onto an object 10, wherein the light beam 2a is superimposed in advance by a beam splitter 9 with a line-shaped light beam 4.

The field stop 5 according to the invention is used to limit and structure the light beam 2a, for example, in order to attenuate certain areas or even to close pixels almost completely, wherein a third light beam 6 is produced, which third light beam 6 marks a specific region of interest (ROI)7 in the monitored area and also projects information for the user onto the object 10. Thus, information can be projected onto a screen temporarily placed there during the setup process.

It should be noted that the beam path is shown in a simplified manner.

Fig. 2 shows a second light section sensor according to the invention, which similarly comprises an optical emitter 1 generating a first light beam 2.

The beam shaping transmission optical unit 3 thus generates a second linear beam 4 which is projected by the transmission optical unit 3 onto the object 10. The second beam 4 is incident on the object 10.

A second light source 1a, for example a laser diode, LED or LED matrix, acting as a projection light source, generates a light beam 2a, which light beam 2a is directed by a first illumination optical unit 8a onto the LC display acting as an active field stop 5. The field stop 5 is also used here as a variable aperture for the structured light beam 2a, wherein structuring is to be understood as weakening to completely close individual pixels. This results in a third light beam 6, the third light beam 6 marking a specific region of interest (ROI)7 on the object 10, but may also be used according to the invention for transmitting information to a user. In this respect, the device internal display may be completely replaced.

Due to the absence of the beam splitter 9, the two light beams 4 and 6 need not only be adjusted but also need to be pivoted relative to each other depending on their distance from the object plane 10. Here, distance measurements are advantageous, which can be done by using PMD time-of-flight sensors (see above) integrated in the system. Such a device is offered by the applicant in various designs, in particular under the name O1D.

Thus, not only the monitoring area is marked, but also information is displayed temporarily, which is very helpful for the operator during the adjustment and/or teaching operation.

For a better overview, a structured receiver, which is not essential for the invention and comprises a receiving optical unit, which detects diffusely reflecting objects located in the monitored area at an angle dependent on the object distance and images them onto the optical receiver in dependence on the angle of incidence, and also a control and evaluation unit, which is of equal importance, is not shown in the two figures.

The emitters 1 and 1a may comprise LEDs, multi-color LEDs (dual color or RGB), or laser diodes, such as Vertical Cavity Surface Emitting Laser (VCSEL) diodes.

The light beam 2 is preferably collimated without limiting the invention thereto. Lenses, cylindrical lenses, micro lenses or fresnel lenses designed with spherical or aspherical surfaces can be used as the optical components 8a and 8 b.

For the field stop 5, the liquid crystal display (LCD for short) mentioned in US2013/0083384a1 becomes problematic, which may be configured as a dot matrix or with predetermined elements (envisaged for special applications) that do not completely exclude the equivalent use of a mechanical field stop 5.

The structures projected onto the monitored area and thus also onto the object 10 are preferably:

1. The interval limit of the closed or open,

2. An adjustment auxiliary mark for the assembly is arranged,

3. The instructions are used for instructing the user to perform the operation,

4. Assembly aid for the operator:

a) The projection of the rectangle is that of the rectangle,

b) Test structure for measuring deformation

For orthogonally mounted sensors and for position detection

Is used to store one or more alternate locations,

5. Including a bar graph of the dragged pointer (match),

6. Axial x-and y-tolerance band indicators.

The display can be designed to be multicolored, which provides better visibility on the subject, readback capability of the sensor, avoidance of resolution loss, for example, when switching from green to red (thereby eliminating the learning index position), by measuring and displaying the spectral separation of the illumination and ultimately the synchronization between the multicolored LED and the active field stop 5.

An LC display known per se as field stop 5 is used in a novel manner to project user information into the monitored area and thus onto the object 10 located in the monitored area. This is done according to the invention during the adjustment or setting process, wherein the currently set ROI (region of interest) 7 (i.e. the measurement field limit) as well as parameters and/or other information can be displayed for the operator.

Optionally, an adjustment indicator and/or an orientation indicator (for right, left, up, down) and/or an indicator for position determination (and confirmation) and/or a bar chart of a dragged pointer designed for evaluating the signal quality and/or a contour for a tolerance band of the object 10 can be projected into the monitored area and thus also onto the object 10.

thus, the operator can easily identify whether the object 10 is in the correct position, in the desired orientation, and within the tolerance band. The drag pointer function allows changes to register.

Reference numerals

1 first light source, optical emitter, (multi-color) LED, laser or VCSEL

1a second light source, projection light source, (multi-color) LED, laser, VCSEL

2 first light beam, preferably laser beam

2a third light beam (optionally structured)

3 Beam-shaping transmitting optical Unit, preferably line Generator, cylindrical lens

4 second modified beam, preferably a linear beam

5 field stop, preferably active (controllable) aperture, e.g. LC display

6 fourth light beam (structured)

7 particular region of interest, region of interest (ROI)

8a illumination optical unit for the fourth light beam 6

8b projection lens for the fourth light beam 6

9 Beam splitter

10 object, monitoring area