TRANSMISSION UNIT AND LIDAR DEVICE WITH OPTICAL HOMOGENIZER

Abstract

A transmission unit of a LIDAR device. The transmission unit includes at least one beam source for generating electromagnetic beams having a linear or rectangular cross section, and transmission optics. The transmission unit has an optical homogenizer which is arranged in a beam path of the generated beams in front of or behind the transmission optics and has at least one lens array. A LIDAR device is also described.

Claims

1-11. (canceled)

12. A transmission unit of a LIDAR device, comprising: at least one beam source configured to generate electromagnetic beams having a linear or rectangular cross section; transmission optics; and an optical homogenizer arranged in a beam path of the generated beams in front of or behind the transmission optics, including at least one lens array.

13. The transmission unit as recited in claim 12, wherein the transmission unit includes a homogenization plane arranged in a region of the transmission optics.

14. The transmission unit as recited in claim 12, wherein the optical homogenizer includes two lens arrays spaced apart from each other and having a multiplicity of cylindrical microlenses, wherein the cylindrical microlenses are each arranged on a surface of the lens arrays, wherein image planes of the cylindrical microlenses are arranged on a focal plane within a spacing between the lens arrays.

15. The transmission unit as recited in claim 14, wherein the lens arrays of the optical homogenizer are arranged in such a way that the surfaces provided with the cylindrical microlenses are directed in a direction of the at least one beam source.

16. The transmission unit as recited in claim 14, wherein the lens arrays of the optical homogenizer are arranged in such a way that the surfaces provided with the cylindrical microlenses are directed toward or away from each other.

17. The transmission unit as recited in claim 12, wherein the optical homogenizer includes a lens array with a first surface and a second surface, wherein a multiplicity of cylindrical microlenses is arranged on the first surface and the second surface, wherein image planes of the cylindrical microlenses are arranged between the first surface and the second surface.

18. The transmission unit as recited in claim 17, wherein the image planes of the cylindrical microlenses are arranged centrally between the first surface and the second surface.

19. The transmission unit as recited in claim 14, wherein a number of the cylindrical microlenses and/or a form of the cylindrical microlenses and/or a size of the cylindrical microlenses of the two lens arrays, is configured to be the same as each other or different from each other, and wherein the form of the cylindrical microlenses and/or the size of the cylindrical microlenses within one surface of the lens array is configured to be constant or varying.

20. The transmission unit as recited in claim 12, wherein the transmission optics are configured to form a linear illumination.

21. The transmission unit as recited in claim 12, wherein the at least one beam source is configured as an array of emitters, wherein the emitters are arranged in such a way that the beams generated by the beam source form a rectangular and/or elongate scanning pattern.

22. A LIDAR device for scanning a scanning area, comprising: a transmission unit including: at least one beam source configured to generate electromagnetic beams having a linear or rectangular cross section, transmission optics, and an optical homogenizer arranged in a beam path of the generated beams in front of or behind the transmission optics, including at least one lens array; and a receiving unit with at least one detector configured to receive beams reflected and/or back-scattered from the scanning area.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 shows a schematic representation of a LIDAR device according to one specific embodiment of the present invention.

[0032] FIG. 2 shows a sectional view of a two-part optical homogenizer, in accordance with an example embodiment of the present invention.

[0033] FIG. 3 shows a sectional view of a one-part optical homogenizer, in accordance with an example embodiment of the present invention.

[0034] FIG. 4 shows a perspective representation of the one-part optical homogenizer with an exemplary beam path, in accordance with an example embodiment of the present invention.

[0035] FIG. 5 shows a schematic intensity distribution of the beams within the plane E of FIG. 4 without an optical homogenizer, in accordance with an example embodiment of the present invention.

[0036] FIG. 6 shows a schematic intensity distribution of the beams within the plane E of FIG. 4 with an optical homogenizer, in accordance with an example embodiment of the present invention.

[0037] FIG. 7 shows a diagram illustrating a change in the intensity distribution due to the use of the optical homogenizer, in accordance with an example embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 shows a schematic representation of a LIDAR device 1 according to one specific embodiment. The LIDAR device 1 has a transmission unit 2 and a receiving unit 4.

[0039] The transmission unit 2 has a beam source 6 with a multiplicity of emitters 8. The emitters 8 in the example illustrated are configured as an array of surface emitters. The emitters 8 can emit generated beams 7 with a for example infrared wavelength range.

[0040] The beams 7 generated by the beam source 6 are bundled by transmission optics 10. The transmission optics 10 are formed as a cylindrical lens that extends in the vertical direction y and has the vertical direction y as its axis of rotation.

[0041] The beam source 6 generates beams 7 having a linear or cuboid cross section. The cross section of the beams 7 extends in an elongate manner along the vertical direction y. The generated beams 7 can be collimated by the transmission optics 10.

[0042] A further optical element 11 that is configured as a part of the transmission optics 10 can be used to take on the vertical beam shaping. The optical element 11 can likewise be configured as a microlens array or as a so-called honeycomb condenser.

[0043] In the beam path in front of the transmission optics 10 and 11 there is arranged an optical homogenizer 12. The optical homogenizer 12 is embodied by way of example as a one-part lens array and will be described in greater detail in the following figures. The optical homogenizer 12 generates beams with a more uniform intensity distribution compared with the generated beams 7, and makes homogeneous illumination approximately in the region of the optical element 11 or the transmission optics 10 possible.

[0044] The receiving unit 4 has a detector 14. The detector 14 can receive beams 15 reflected and/or back-scattered from the scanning area 1 and convert them into electrical measurement data.

[0045] Furthermore, the receiving unit 14 may have optional receiving optics that form the reflected and/or back-scattered beams 15 or focus them on the detector 14.

[0046] FIG. 2 shows a sectional view of a two-part optical homogenizer 13. The optical homogenizer 13 has a first lens array 16 and a second lens array 18. Each lens array 16, 18 has a multiplicity of cylindrical microlenses 20.

[0047] The cylindrical microlenses 20 are arranged on one surface 22 in each case of the respective lens arrays 16, 18. The cylindrical microlenses 20 run in a transverse direction x or transversely to the vertical direction y.

[0048] A surface 24 arranged in the opposite direction to the cylindrical microlenses 20 is formed flat or without further texturing or contouring. The lens arrays 16, 18 are aligned in such a way that the flat surfaces 24 face one another.

[0049] The generated beams 7 are focused by the respective cylindrical microlenses 20 of the first lens array 16 and imaged on a focal plane F. In particular, each cylindrical microlens 20 generates an image 26 on the focal plane F. The images 26 of the cylindrical microlenses 20 are imaged in the vertical direction y overlapped along the focal plane F.

[0050] The images 26 of the cylindrical microlenses 20 of the first lens array 16 are used as objects by the cylindrical microlenses 20 of the second lens array 18. Thus the already overlapped images 26 are focused anew and overlapped, producing a homogeneous intensity distribution of the resulting beams 9 that are emitted into the scanning area A.

[0051] The focal plane F in this case forms an image plane for the first lens array 16 and for the second lens array 18. The respective focal points of the cylindrical microlenses may preferably be arranged offset relative to the focal plane F.

[0052] FIG. 3 shows a sectional view of a one-part optical homogenizer 12. Unlike the optical homogenizer 13 shown in

[0053] FIG. 2, this one is configured in one part. The one-part optical homogenizer 12 has a lens array 28 having a first surface 22 and a second surface 24.

[0054] The cylindrical microlenses 20 are arranged both on the first surface 22 and on the second surface 24. The cylindrical microlenses 20 of the respective surfaces 22, 24 have a common image plane that runs through the focal plane F.

[0055] In the example illustrated, the focal plane F runs in the direction of propagation z of the beams 7 centrally or in a centered manner through the lens array 28.

[0056] FIG. 4 shows a perspective representation of the one-part optical homogenizer 12 with an exemplary beam path. Furthermore, a plane E is illustrated which is used to illustrate the further figures. The plane E is arranged downstream from the optical homogenizer 12 and extends in an x-y plane that runs transversely to the direction of propagation z.

[0057] FIG. 5 shows a schematic intensity distribution I of the beams 9 emitted into the scanning area A within the plane E of FIG. 4 without the use of an optical homogenizer 12.

[0058] The beams 9 have a transverse intensity distribution I with a clearly marked peak. In particular, the intensity distribution I is essentially Gaussian.

[0059] FIG. 6 shows a schematic intensity distribution I of the beams 9 within the plane E of FIG. 4 with an optical homogenizer 12 being used. In such case, a clear deviation from the Gaussian intensity distribution I of FIG. 5 can be recognized. The beams 9 have a homogenized intensity distribution I.

[0060] The difference between the intensity distribution Il of FIG. 5 and the intensity distribution 12 of FIG. 6 is illustrated in the diagram shown in FIG. 7.

[0061] The diagram shows an intensity I along the vertical direction y and illustrates the constant intensity curve 12 of the beams 9 that can be set by the optical homogenizer 12, 13.

[0062] In one advantageous manifestation of the present invention, one or more optical systems that bring the beams 7 into a desired form are located in the homogenization plane E. In the case of linear illumination, the at least one optical system may serve for collimation for producing low divergence in one direction in space and for producing fanning or a great divergence in the other direction in space.