WO2017005653A1

WO2017005653A1 - Detector unit for an optical sensor device

Info

Publication number: WO2017005653A1
Application number: PCT/EP2016/065581
Authority: WO
Inventors: Lin Lin; Peter Horvath
Original assignee: Valeo Schalter Und Sensoren Gmbh
Priority date: 2015-07-03
Filing date: 2016-07-01
Publication date: 2017-01-12
Also published as: DE102015110767A1

Abstract

The invention relates to a detector unit (1) for an optical sensor device for detecting at least one received optical signal, comprising an optical collimation element (2) for collimating the at least one received optical signal and comprising a detection element (3) for detecting the received collimated optical signal. The detection element (3) is arranged on a focal plane (7) of the collimation element (2) in at least some regions, and the detection element (3) has at least two detector surfaces (4a, 4b, 4c) with pixel fields. The detector surfaces (4a, 4b, 4c) are oriented differently at least in some regions in order to achieve a large detection region with a high resolution while simultaneously having a low signal-to-noise ratio for an optical sensor device.

Description

Detector unit for an optical sensor device

The invention relates to a detector unit for an optical sensor device, for detecting at least one optical received signal, with an optical

A collimation element for collimating the at least one received optical signal and a detection element for detecting the collimated optical

Receiving signal, wherein the detection element is disposed at least partially in a focal plane of the Kollimationselementes. The invention also relates to an optical sensor device with such a detector unit and to a motor vehicle with such a detector unit or such an optical sensor device.

In modern motor vehicles, a variety of different sensor devices are used. Straight optical sensor devices are widely used here. In this case, optical sensor devices are known in which surfaces or bodies in a vicinity of the sensor device and thus of the motor vehicle are swept line or raster-like with a light beam in order to measure the respective surfaces or bodies, to process and / or to produce an image. This can be done, for example, in a laser scanning device by a laser light beam. such

Laser scanning devices are also known as "laser scanners" or as "lidars". In these sensor devices come accordingly both transmitting units and

Detector units are used. In conventional detector units, lights which are mostly reflected by the surroundings are directed to detection elements with individual pixels, for example so-called avalanche or avalanche photodiodes. These individual pixels or pixels usually also absorb light, for example sunlight, from other directions.

Thus, DE 10 2012 101 460 A1 discloses a lidar sensor for a

Driver assistance system of a motor vehicle. The sensor has several

Reception areas, each associated with a detector.

This results in the task of a large optical sensor device

Reach detection range with a high resolution and low signal-to-noise ratio. This object is solved by the subject matter of the independent claim. Advantageous embodiments will become apparent from the dependent claims, the description and the figures.

A detector unit according to the invention for an optical sensor device is designed to detect at least one optical received signal. The optical sensor device may be an active optical sensor device in which a transmission signal is emitted into an environment of the sensor device and a reflection of this transmission signal as a received signal by the detector unit of the optical sensor device detected and finally, for example by the

Detector unit or a computing unit is evaluated. Such an optical sensor device may be a light scanning device, in particular a laser scanning device or a laser scanner. The detector unit in this case comprises an optical collimation element for collimating the at least one optical received signal and a detection element for detecting the collimated optical received signal. In this case, the detection element is at least partially, so partially or completely, arranged in a focal plane of the Kollimationselementes. Collimating can also be used here as bundling or focusing the optical

Receive signal to be understood.

In order to realize a large detection range for the detector unit with high resolution and at the same time low signal-to-noise ratio, this has

Detection element at least two detector surfaces with pixel fields, which are also known as "pixel arrays." In each pixel of the pixel fields, a signal is individually detectable here

oriented differently. Thus, normal vectors of the detector surfaces are at least partially, ie partially or completely, not parallel to one another. The detector surfaces can thus be tilted against each other, for example. The pixel fields each have a plurality of pixels or pixels, in each of which an optical signal, for example the optical received signal, is converted into an electrical signal.

This has the advantage that the detector unit or the optical sensor device with the detector unit, which then includes, for example, a corresponding transmitter unit, can be designed such that each pixel can only receive signals from a very small solid angle range and thus convert it into an electrical signal. As a result, a noise, which, for example, a scattered light of a further optical reception signal or caused by other lights such as sunlight avoided. Accordingly, a low signal-to-noise ratio is achieved. At the same time, the demands on the optical collimation element decrease due to the differently oriented detector surfaces. Thus, the detector surfaces may comprise a particularly large number of pixels in order to realize a high resolution and yet be arranged in each case in the focal plane of the collimation element. In this case, the focal plane of the Kollimationselementes also be curved. Such a curvature is an effect which, as is known, becomes visible, for example in the case of converging lenses, when a light strikes the lens at a very large angle of incidence with respect to solder on a principal plane of the respective lens. Thus, by means of a simple and cost-effective optical collimation element, an optical received signal can be imaged sharply and correspondingly high-resolution onto the respective pixels of the detector surfaces. Due to the different orientation of the

Detector surfaces can thus collimation errors at least partially, so be compensated in whole or in part. It can be achieved in one direction, for example in a horizontal direction, a particularly high resolution by multiple detector surfaces can be strung together.

In the embodiment according to the invention it is provided that the detector surfaces each have non-curved flat surfaces (or are not curved flat surfaces), which are tilted against each other. A non-curved flat surface lies completely in a plane which is spanned by two vectors, which are mathematically independent of each other, ie non-parallel. In this case, the detection sides of the detector surfaces facing the optical collimator element enclose an angle in a predetermined plane which is smaller than 180 °. The flat surfaces are thus non-parallel surfaces. The predetermined plane can stand in particular perpendicular to the two surfaces. This has the advantage that the different orientation of the detector surfaces can be realized in a particularly simple and cost-effective manner. In particular, the detector surfaces can adjoin one another in this case. This has the advantage that the detector surfaces a

Total detector area forms, which has no gaps. Accordingly, the at least one optical received signal from the surroundings of the detector unit can thus be detected without gaps, without requiring complex optical constructions.

In a particularly advantageous embodiment, it is provided that the

Detector surfaces have normal vectors, which in the horizontal plane all parallel to each other. Accordingly, then the detector surfaces only in one plane, here the horizontal plane, inclined to each other. This has the advantage that the at least one optical received signal can be detected from a particularly large angular range in the horizontal plane.

In another embodiment, it is provided that the collimating element comprises at least two optical lenses, whose main optical planes lie in planes not parallel to one another, wherein in each case one detector surface is arranged in a focal plane of the respective associated optical lens. Thus, the inclination (or angle) of the principal planes to each other corresponds to the inclination (or angle) of the detector surfaces to each other. This has the advantage that the detector surfaces can each be arranged in a region of the focal planes, which is particularly flat or flat, that is not curved. This allows a particularly high optical quality and thus a particularly high resolution can be achieved. It remains despite less

Requirements for the optical lenses obtained the above-described advantages of the large detection range and low signal-to-noise ratio at high resolution.

In a further embodiment, it is provided that the collimation element has only one main optical plane or only mutually parallel extending main optical planes. In particular, the collimation element here can have only one optical lens or a plurality of optical lenses with main planes parallel to one another. Just here, the detection element with the differently oriented detector surfaces is particularly advantageous because so inevitably in a large

Incident angle of the optical signal received on the Kollimationselement occurring effects, which manifest themselves in a curvature of the focal plane are compensated particularly effective, thus, even at a large angle of incidence, which is associated with a large detection range, by the Kollimationselement an accurate collimation of the optical received signal to the respective detection element take place. Thus, a high resolution is achieved. From the high resolution, as described above, a favorable signal-to-noise ratio is derived, since with a plurality of pixels with a small receiving range (also known as field of view, FOV) less noise is detected by each pixel.

It can be provided that the detector surfaces are arranged at least partially or partially in the focal plane of the Kollimationselementes. The focal plane can here just in an edge region, in which at a large angle of incidence of the optical reception signal, the optical received signal is collimated, be curved. The detector surfaces can therefore be arranged at least partially in a curved region of the focal plane of the collimation element. A curved region of the focal plane is to be understood here in particular as the region of the focal plane in which the curvature is no longer negligible without an optical error being greater than a predefined limit value. This has the advantage that through the

Arrangement of the detector surfaces at least partially in the curved focal plane, a large detection range for the detector unit is achieved. Especially in the case of the large angles of incidence typical for a large detection range, the optical errors, for example a blur or a curvature of the focal plane, are particularly pronounced, so that the different orientation of the detector surfaces is particularly advantageous here.

In a particularly preferred embodiment it is provided that the

Detector unit comprises three or more detector surfaces and adjacent detector surfaces are each oriented at a predetermined angle to each other. Two detector surfaces are considered adjacent here if they are nearest neighbors. They can also be adjacent or abut. They then in particular each include an angle, the predetermined angle. The predetermined angle is in particular between 130 ° and 150 °, preferably 140 °. If the detector surfaces are understood as oriented surfaces, angular amounts of between 210 ° and 230 ° are, in addition to the stated angular amounts, depending on the definition of the associated angles

in particular 220 ° equivalent. This has the advantage that even with three detector surfaces a detection range can be achieved, which encloses 120 ° in a plane, for example, the horizontal plane. Thus, the high resolution and the low signal-to-noise ratio are realized simultaneously for one-third of an overall environment. For example, in a vertical plane perpendicular to the horizontal plane, the detection area may cover a vertical angle of 12 °.

In a further embodiment it is provided that the pixel fields of the

Detector surfaces are two-dimensional pixel fields. In particular, they may be non-square pixel fields which have more than one pixel in a vertical direction which is perpendicular to the horizontal plane and a multiple of the pixels of the vertical direction in a horizontal direction perpendicular to the vertical direction in the horizontal plane. The multiple does not have to be an integer multiple here. For example, the detector surfaces may each have 400 pixels or pixels in the horizontal direction and 120 pixels or pixels in the vertical direction. Thus, for example, in the last-mentioned example with a horizontal detection angle of 120 ° and a vertical detection angle of 12 °, a spatial resolution of 0.1 ° x 0.1 ° can be achieved. This has the advantage that a particularly high resolution is achieved. Due to the fact that the detector surfaces are oriented differently, the respective pixel fields can, however, at least partially in one

Burning plane of the Kollimationselementes be arranged so that an accurate

Collimation takes place and this high resolution is actually realized.

In a further advantageous embodiment it is provided that by the

Kollimationselement received signals from a horizontal angle range of 90 ° or more, in particular of less than 150 ° to the focal plane of the

Kollimationselementes are collimated. Optical reception signals from an angular range of 120 ° may be collimated onto the focal plane of the collimation element. In addition, optical reception signals from a predetermined vertical angle range, for example an angle range between 10 ° and 20 °, preferably 12 °, can also be collimated by the collimation element onto the focal plane of the collimation element. This has the advantage of being a great one

Detection area is realized.

The invention also relates to an optical sensor device with a detector unit according to one of the preceding claims. The advantages arise accordingly.

In a particularly advantageous embodiment of the optical sensor device, it is provided that the optical sensor device also has a transmitting unit. The transmitting unit comprises for emitting at least one transmission signal at least two independently activatable transmitting elements, which are each associated with the detector elements. The from an environment of the optical

Sensor device to the detector unit towards reflected portions of the transmission signal are part of the received signal or form the received signal. This has the advantage that a particularly low signal-to-noise ratio is achieved because the

Sending elements are serially exclusively activated, so that arrives in different detector units or different pixels of the detector units at the same time always only the respective transmission signal corresponding received signal or corresponding part of the received signal. This is a "crosstalk", which by overshooting the different transmission signals in different

Detector units or different pixels of the detector units caused in, prevented. Accordingly, the signal-to-noise ratio (SNR) is improved.

In a further advantageous embodiment of the optical sensor device is provided that the transmitting units are each designed to emit a respective associated transmission signal in a horizontal angle range of 40 ° or less. The optical sensor device can here in particular comprise three or more transmission units. Thus, with each of the associated transmit signals, the surroundings of the optical sensor device can be scanned in a horizontal angle range of 40 ° or less. The number of transmitting units preferably corresponds to the number of detector units. Just by three transmission units, a large detection range with a detection angle of, for example, 3x40 = 120 ° can be scanned or detected with little effort. With more transmitting units, a lesser

horizontal angle range to be provided per pro unit. This results in the advantage that more detector units associated with the transmission signals for

Use can come, which can then be arranged, for example, again in more detail in the curved focal plane of the Kollimationselementes.

The invention also relates to a motor vehicle with a detector unit according to one of the described embodiments or with an optical sensor device as described in the last paragraphs.

With the information horizontal direction and vertical direction are the at

intended use and intended arrangement of the

Specified in the detector unit or the optical sensor device and at a given before the detector unit or the optical sensor device and in the direction of the detector unit or optical sensor device views given observer positions and orientations.

The features and feature combinations mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respectively specified combination but also in other combinations or in isolation, without the frame to leave the invention. Thus, embodiments of the invention are to be regarded as encompassed and disclosed, which are not explicitly shown and explained in the figures, however, emerge and can be produced by separated combinations of features from the embodiments explained. There are thus also It should be understood, however, that it is intended that these terms and combinations of features and features be considered to be disclosed that do not share all features of an original formulated dependent or independent claim.

An embodiment of the invention will be explained in more detail with reference to a schematic drawing. Showing:

Fig. 1 is a schematic perspective view of a first exemplary

Embodiment of a detector unit.

In the figure, the same or functionally identical elements with the same

Provided with reference numerals.

FIG. 1 shows a schematic perspective view of an exemplary embodiment of a detector unit 1. In this case, the detector unit 1 comprises an optical collimation element 2 and a detection element 3. The detection element 3 comprises several, in the present case three, detector surfaces 4a, 4b, 4c. These detector surfaces 4a, 4b, 4c are embodied here as flat and rectangular and comprise a multiplicity of

Pixels or pixels arranged in the form of pixel fields. These pixels or pixels are not shown here for reasons of clarity.

The present three detector surfaces 4a, 4b, 4c are all perpendicular to a horizontal plane, which corresponds to the x-z plane in the drawing. In this case, the planes are in each case tilted by a predetermined angle a, which in the example shown is 120 °. The respective adjacent detector surfaces 4a, 4b; 4b, 4c thus each include the predetermined angle α. The can

Detector surfaces 4a, 4b, 4c in another embodiment, which is not shown to be spaced apart. In this case, the detector surfaces 4a, 4b, 4c are then in a respective plane, which intersects with the plane of the respectively adjacent detector surface 4a, 4b, 4c at the predetermined angle α.

The collimating element 2 in the present case comprises a single lens 5, which is also arranged with its main plane perpendicular to the horizontal plane. In the present case, several light bundles 6a, 6b and 6c are also drawn. These have the form of vertical light bands in the selected representation, which are each parallel to the

Horizontal plane in the vertical, ie perpendicular to the horizontal plane, arranged side by side, extend. Each of the three vertical light bundles 6a, 6b, 6c is in the present case with light of a different wavelength, in particular laser light of a respective one predetermined, of the other light beams 6a, 6b, 6c different wavelength shown and executed. The vertical light bundles 6a, 6b, 6c, thereby encounter the collimating element 2 at a respective angle of incidence β. The angle of incidence β is defined as the angle between a perpendicular L on the main plane of the collimating lens 5 and the respective light beam of the light beam 6a, 6b, 6c. In the present case, the angle of incidence β for the two light bundles 6a and 6c is identical and is 40 °. In the example shown, the middle light beam 6b strikes the lens 5 exactly perpendicularly, ie at an angle of .beta. Equal to 0.degree. The light beams 6a, 6b, 6c, in the present case comprise the at least one optical received signal. However, the optical received signal may also be only individual rays of the illustrated light bundles 6a, 6b, 6c. The illustrated light bundles 6a, 6b, 6c can also be a temporally integrated representation of the respective optical signals received at different times. At one time, only one light beam of the respective light beam 6a, 6b, 6c would then be present.

The optical signals, which are symbolized here by the light bundles 6a to 6c, are imaged by the lens 5 as a collimating element 2 onto a focal plane 7 of the collimation element 2. This focal plane 7 is curved in the example shown. Due to the different orientations of the detector surfaces 4a, 4b, 4c, which are also visualized by the respective associated normal vectors 8a, 8b, 8c, one or more optical received signals can be detected by the detector unit 1 from a large area of an environment 9 of the detector unit 1 , Since the respective detector surfaces 4a, 4b, 4c are arranged in the focal plane 7, and moreover have a multiplicity of pixels in the pixel fields, a particularly high resolution can thus be achieved. Even by arranging the detector surfaces 4a, 4b, 4c in the focal plane 7 of the collimating element 2, the maximum resolution is actually realized by a sharp image and accurate collimation and scattering effects which affect the detection of the optical received signal are avoided. This can be further enhanced by using, for example, a transmitting unit which, for example, only individual ones at the same time

Light rays of the respective vertical direction perpendicular to the horizontal plane

superimposed light beams, which form the light beams 6a, 6b, 6c, emit. This avoids that several pixels of the detector surfaces 4a, 4b, 4c are activated at the same time by an optical received signal.

Claims

claims

1 . Detector unit (1) for an optical sensor device, for detecting at least one optical received signal, with

- An optical collimating element (2) for collimating the at least one optical received signal and with

- A detection element (3) for detecting the collimated optical

Receiving signal, wherein the detection element (3) at least partially in a focal plane (7) of the Kollimationselementes (2) is arranged

characterized in that

the detection element (3) at least two detector surfaces (4a, 4b, 4c) with

Having pixel areas, wherein the detector surfaces (4a, 4b, 4c) are at least partially oriented differently and each having flat surfaces which are tilted against each other, wherein the optical collimator element (2) facing detection sides of the detector surfaces (4a, 4b, 4c) in an angle (a) are arranged to each other and wherein the angle (a) is smaller than 180 °.

2. detector unit (1) according to claim 1,

characterized in that

the collimating element (2) comprises at least two optical lenses (5a, 5b, 5c) whose principal optical planes lie in planes which are not parallel to one another, wherein in each case one detector surface (4a, 4b, 4c) in a focal plane of the respective

associated optical lens (5a, 5b, 5c) is arranged.

3. detector unit (1) according to claim 1,

characterized in that

the collimating element (2) only one or only mutually parallel optical

Main planes, in particular only an optical lens (5) or a

Plurality of optical lenses with parallel principal planes.

4. detector unit (1) according to claim 3,

characterized in that the detector surfaces (4a, 4b, 4c) are each arranged at least in regions in the focal plane of the collimation element (2).

5. detector unit (1) according to claim 3 or 4,

characterized in that

the detector unit (1) comprises three or more detector surfaces (4a, 4b, 4c) and adjacent detector surfaces (4a, 4b, 4c) each oriented at a predetermined angle (a) to each other, the angle (a) in particular between 130 ° and 150 ° is preferably 140 °.

6. detector unit (1) according to one of the preceding claims,

characterized in that

the pixel fields of the detector surfaces (4a, 4b, 4c) are two-dimensional pixel fields, in particular non-square pixel fields which have more than one pixel in a vertical direction and a multiple of the pixels of the vertical direction in a horizontal direction perpendicular to the vertical direction ,

7. Detector unit (1) according to one of the preceding claims,

characterized in that

by the collimation element (2) receiving signals from a horizontal angle range of 90 ° or more, in particular of less than 150 °, preferably from an angular range of 120 ° to the focal plane (7) of the

Kollimationselementes (2) are collimated.

8. Optical sensor device with a detector unit (1) according to one of

previous claims.

9. An optical sensor device according to claim 8,

characterized in that

the optical sensor device also has a transmitting unit, and the

Transmitting unit for emitting at least one transmission signal comprises at least two independently activatable transmitting elements, wherein from an environment (9) of the optical sensor device to the detector unit (1) out reflected portions of the transmission signal are part of the received signal or form the received signal.

10. An optical sensor device according to claim 8 or 9,

characterized in that

the transmitting units are each designed to radiate a respective associated transmission signal in a horizontal angle range of 40 ° or we niger.

1 1. Motor vehicle with a detector unit (1) according to one of claims 1 to 7 or with an optical sensor device according to claims 8 to 10.