Abstract
A LIDAR device for scanning a scanning area using at least two beams includes at least two beam sources for generating at least two beams, a generating optics for shaping the at least one generated beam, a receiving unit for receiving and evaluating at least one beam reflected on an object, and an optical bandpass filter for absorbing spurious reflections, each beam source generating at least one beam having a wavelength that is adjustable depending on an emission angle of the at least one beam.
Claims
1-10. (canceled)
11. A LIDAR device for scanning a scanning area, the LIDAR device comprising: at least two beam sources; a generating optics; a receiver; and an optical bandpass filter; wherein: each of the at least two beam sources is configured to generate at least one respective beam having a wavelength that is adjustable depending on an emission angle of the at least one beam; the generating optics is configured to shape at least one of the generated beam; the receiver is configured to receive and evaluate at least one beam that is reflected by an object; and the optical bypass filter is configured to absorb spurious reflections.
12. The LIDAR device of claim 11, wherein the wavelength of the at least one respective beam is adjustable using the at least one beam source.
13. The LIDAR device of claim 11, wherein the wavelength of the at least one respective beam is adjustable using a diffractive optical element provided in the LIDAR device.
14. The LIDAR device of claim 13, wherein the diffractive optical element is situated in the at least one beam source.
15. The LIDAR device of claim 13, wherein the diffractive optical element is situated outside the at least one beam source.
16. The LIDAR device of claim 11, wherein the at least two beam sources are single emitters of a laser bar.
17. The LIDAR device of claim 11, wherein a plurality of the at least two beam sources beam sources are of a laser bar and include a shared diffractive optical element.
18. The LIDAR device of claim 17, wherein the diffractive optical element has a wavelength selectivity that changes across an extension of the diffractive optical element.
19. The LIDAR device of claim 11, wherein the beams of the at least two beam sources are generatable simultaneously the at least two beam sources.
20. The LIDAR device of claim 11, wherein the beams of the at least two beam sources are generatable one after another by the at least two beam sources.
21. The LIDAR device of claim 11, wherein the LIDAR device is configured to perform the scanning of the scanning area using at least two beams that are formed, with respect to a direction from the at least two beam sources, downstream of the generating optics.
22. A method for scanning a scanning area using a LIDAR device that includes at least two beam sources, a generating optics, a receiver, and an optical bypass filter, the method comprising: using the at least two beam sources, generating at least two beams; using the generating optics, shaping the at least two beams and then emitting each of the at least two beams at a respective emission angle, wherein respective wavelengths of the emitted beams depend on their respective emission angles; deflecting the emitted the at least two beams; receiving, by the receiver, a beam reflected by an object after the reflected beam is filtered through the optical bypass filter.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 shows a schematic representation of a transmission path of a LIDAR device according to an example embodiment of the present invention.
[0023] FIG. 2 shows a schematic representation of a reception path of a LIDAR device according to an example embodiment of the present invention.
[0024] FIGS. 3a-3c show schematic representations of options for adjusting a wavelength using diffractive optical elements of a LIDAR device according to respective example embodiments of the present invention.
[0025] FIG. 4 shows a sequence of a method according to an example embodiment of the present invention.
DETAILED DESCRIPTION
[0026] FIG. 1 shows a schematic representation of a transmission path of a LIDAR device 1 according to an example embodiment of the present invention. LIDAR device 1 includes two beam sources 2, 4 that are designed as infrared lasers 2. First beam source 2 is situated in such a way that it emits generated beams 3 that extend along an optical axis of transmission path A. Optical axis A of the transmission path is congruent with an optical axis of a generating optics 6 in this case. Second beam source 4 is spaced apart from first beam source 2. Beam 5 generated by second beam source 4 therefore extends in parallel to optical axis A and is also spaced apart from optical axis A. According to the example embodiment, second beam source 4 generates beams 5 having a wavelength that is smaller than the wavelength of beams 3 generated using first beam source 2. Thereafter, generated beams 3, 5 are shaped by generating optics 6. According to an example embodiment, generating optics 6 is a cylindrical lens 6 that linearly shapes or focuses generated beams 3, 5. Generated beams 3, 5 therefore become shaped beams 7, 9. Due to the focusing, an angular offset is applied, in particular, to generated beams 5 spaced apart from optical axis A. Therefore, shaped beams 7, 9 intersect at a focal point B of generating optics 6 before shaped beams 7, 9 impact a deflection unit 8. In this case, deflection unit 8 is a biaxially swivelable mirror 8 that deflects shaped beams 7, 9 along a horizontal scanning angle and along a vertical scanning angle in a meandering manner. The vertical scanning angle and the horizontal scanning angle cover a scanning area in this case that can be scanned by shaped beams 7, 9. Due to the deviating angle of shaped beams 9 of second beam source 4, these shaped beams 9 are emitted from the LIDAR device at a greater angle into the scanning area.
[0027] FIG. 2 shows a schematic representation of a reception path of a LIDAR device 1 according to an example embodiment of the present invention, which can be used with the transmission path illustrated in FIG. 1. Emitted, shaped beams 7, 9 can be reflected on objects 10. Due to the reflection, shaped beams 7, 9 become reflected beams 11, 13, respectively. Beams 5, 9 generated by second beam source 4 have an angle in relation to beams 3, 7 generated by first beam source 2. Therefore, objects 10 can be scanned by beams 5, 9 that have a greater angle with respect to LIDAR device 1 than do objects 10 scannable using beams 3, 7. For the sake of simplicity, only one object 10 is represented. Generated, shaped, and subsequently reflected beams 3, 5, 7, 9, 11, 13 can be received by a receiving unit 12. Receiving unit 12 is made up of an optical bandpass filter 14 that is installed upstream from a receiving optics 16. Receiving unit 12 includes a detector 18. Beams 3, 11 that are generated by first beam source 2 and are reflected, impact filter 14 nearly perpendicularly and can transmit through filter 14. Beams 5, 13 that are generated by second beam source 4 and are reflected, impact filter 14 at an angle. Due to the angular offset, a transmitted wavelength range of filter 14 shifts toward shorter wavelengths. Second beam source 4 generates generated beams 5 having a shorter wavelength, so that beams 13 that are generated by second beam source 4 and are reflected, are adapted to the shift of the transmitted wavelength range of filter 14 and can also transmit through filter 14. If reflected beams 13 of second beam source 4 did not have an adapted wavelength, their wavelength would possibly lie outside the transmitted wavelength range of filter 14, due to their angular offset, and would therefore be blocked or reflected by filter 14. Thereafter, the beams transmitted through filter 14 are deflected by receiving optics 16 onto detector 18 and, there, are registered and evaluated.
[0028] In FIGS. 3a and 3b, wavelength-stabilized beam sources 2 of a LIDAR device 1 are illustrated as internally including diffractive optical elements 20 according to example embodiments of the present invention. FIG. 3a shows a distributed feedback (DFB) laser 2. Diffractive optical element 20 is installed, in the form of a periodic structure in this case, within an active zone of beam source 2 designed as a semiconductor laser. Diffractive optical element 20 filters beams having a certain wavelength already within a resonator of semiconductor laser 2. Depending on a geometry of diffractive optical element 20, beams 3 having a defined set wavelength can be generated. FIG. 3b shows another principle of a wavelength stabilization of a beam source 2. Semiconductor laser 2 is designed as a distributed Bragg reflector (DBR) laser 2 in this case. In this case, diffractive optical element 20 acts as a reflector in an area of the beam source 2. In the case of a LIDAR device 1, differently wavelength-stabilized beam sources 2 can be utilized, also in combination, for generating beams 3, 5.
[0029] FIG. 3c shows a portion of a transmission path of a LIDAR device 1 according to another example embodiment. Beam sources 2 are single emitters of a semiconductor laser bar 22 in this case. Beam sources 2 generate multiple beams 3 that are focused by a generating optics 6 into one linearly shaped beam 7. Thereafter, shaped beam 7 passes through a diffractive optical element 20 that introduces a wavelength offset 24 along linear beam 7. In this case, edge regions of linear beam 7 have a shorter wavelength than central areas of linear beam 7.
[0030] FIG. 4 shows a sequence of a method 30 according to an example embodiment. At step 32, at least one beam is generated. At step 34, a wavelength of the at least one generated beam is adjusted using at least one diffractive optical element or using at least one beam source based on an emission angle and based on a transmitted wavelength range of a filter. Thereafter, at step 36, the at least one beam is shaped and deflected along a scanning area. At step 38, the beams can be reflected on an object. Thereafter, at step 40, the reflected beams are filtered and received.
