Scanning LiDAR system and method with unitary optical element
A LiDAR apparatus includes a first substrate, a laser diode on a surface of the substrate for outputting light, a fast axis collimator (FAC) lens receiving the light and generating an at least partially collimated light beam, a polarizing beam splitter optically coupled to the FAC lens, at least a portion of the light beam passing through the polarizing beam splitter to a region being observed by the LiDAR apparatus. An opaque coating on the back side of an aperture element coupled to the polarizing beam splitter is patterned to provide a transparent aperture. At least a portion of light returning to the LiDAR apparatus from the region being observed is directed by the polarizing beam splitter, through the transparent aperture in the opaque coating on the aperture element, through the at least partially reflective optical element to an optical detector mounted on the substrate.
1. A LiDAR apparatus, comprising:
a first substrate;
a unitary optical element mounted on the first substrate, the unitary optical element comprising:
a fast axis collimator (FAC) lens receiving light from a laser diode source and generating therefrom an at least partially collimated light beam,
a polarizing beam splitter optically coupled to the FAC lens, at least a portion of the at least partially collimated light beam passing through the polarizing beam splitter to a region being observed by the LiDAR apparatus,
an aperture element optically coupled to the polarizing beam splitter, and
an opaque coating formed on a back side of the aperture element, the opaque coating being patterned to provide a transparent aperture; wherein
at least a portion of light returning to the LiDAR apparatus from the region being observed is directed by the polarizing beam splitter, through the transparent aperture in the opaque coating on the aperture element, to an optical detector.
2. The LiDAR apparatus of claim 1 , further comprising a second substrate in fixed spatial relation to the first substrate; wherein, the optical detector is mounted on the second substrate.
3. The LiDAR apparatus of claim 2 , wherein the first and second substrates are held in stationary spatial relation with respect to each other by a supporting frame.
4. The LiDAR apparatus of claim 2 , wherein the first and second substrates are held in stationary spatial relation substantially perpendicular to each other by a supporting frame.
5. The LiDAR apparatus of claim 1 , wherein the unitary optical element further comprises a quarter wave plate optically coupled to the polarizing beam splitter between the polarizing beam splitter and the region being observed.
6. The LiDAR apparatus of claim 1 , wherein the unitary optical element is a one-piece precision glass optical element.
7. The LiDAR apparatus of claim 1 , wherein the laser diode source is part of the unitary optical element.
8. The LiDAR apparatus of claim 1 , further comprising an optical band pass filter in an optical path of the LiDAR apparatus, the optical band pass filter being adapted to pass the portion of light returning to the LiDAR apparatus from the region being observed and block other light entering the band pass filter.
9. The LiDAR apparatus of claim 8 , wherein the optical band pass filter comprises one or more optical coatings formed on a component of the LiDAR apparatus.
10. The LiDAR apparatus of claim 9 , wherein the component of the LiDAR apparatus on which the one or more optical coatings are formed is the polarizing beam splitter.
11. The LiDAR apparatus of claim 9 , wherein the component of the LiDAR apparatus on which the one or more optical coatings are formed is the aperture element.
12. The LiDAR apparatus of claim 9 , wherein the component of the LiDAR apparatus on which the one or more optical coatings are formed is a cover over the optical detector.
13. A LiDAR apparatus, comprising:
a substrate;
a laser diode on a surface of the substrate for outputting light;
a fast axis collimator (FAC) lens on the surface of the substrate for receiving the light and generating therefrom an at least partially collimated light beam;
a polarizing beam splitter optically coupled to the FAC lens for receiving the at least partially collimated light beam, at least a portion of the at least partially collimated light beam passing through the polarizing beam splitter to a region being observed by the LiDAR apparatus;
an aperture element optically coupled to the polarizing beam splitter;
an opaque coating formed on a back side of the aperture element, the opaque coating being patterned to provide a transparent aperture;
an at least partially reflective optical element on the surface of the substrate for receiving light from the transparent aperture in the opaque coating on the aperture element and directing the received light from the transparent aperture in the opaque coating on the aperture element in a direction toward the surface of the substrate; and
an optical detector optically coupled to the at least partially reflective optical element; wherein
at least a portion of light returning to the LiDAR apparatus from the region being observed is directed by the polarizing beam splitter, through the transparent aperture in the opaque coating on the aperture element, through the at least partially reflective optical element to the optical detector.
14. The LiDAR apparatus of claim 13 , wherein the at least partially reflective optical element comprises a prism.
15. The LiDAR apparatus of claim 14 , wherein the prism is a 45-degree prism.
16. The LiDAR apparatus of claim 14 , wherein the prism is a 50-degree prism.
17. The LiDAR apparatus of claim 14 , wherein a reflective angle of the prism is determined at least in part by a direction between the prism and the optical detector.
18. The LiDAR apparatus of claim 14 , wherein a reflective angle of the prism is controlled at least in part by selection of an index of refraction of the prism.
19. The LiDAR apparatus of claim 13 , wherein the at least partially reflective optical element comprises a mirror.
20. The LiDAR apparatus of claim 13 , wherein the at least partially reflective optical element comprises a reflective coating formed on a surface of an optical element.
21. The LiDAR apparatus of claim 13 , wherein the optical detector is on the surface of the substrate.
22. The LiDAR apparatus of claim 13 , wherein the FAC lens, the polarizing beam splitter, and the aperture element are formed as a unitary optical element on the surface of the substrate.
23. The LiDAR apparatus of claim 22 , wherein the unitary optical element is a one-piece precision glass optical element.
24. The LiDAR apparatus of claim 22 , wherein the at least partially reflective optical element is also formed as part of the unitary optical element.
25. The LiDAR apparatus of claim 22 , wherein the laser diode is also formed as part of the unitary optical element.
26. The LiDAR apparatus of claim 13 , further comprising a quarter wave plate optically coupled to the polarizing beam splitter between the polarizing beam splitter and the region being observed.
27. The LiDAR apparatus of claim 13 , wherein:
the quarter wave plate, the FAC lens, the polarizing beam splitter, and the aperture element are formed as a unitary optical element on the surface of the substrate; and
the unitary optical element is a one-piece precision glass optical element.
28. The LiDAR apparatus of claim 13 , further comprising an optical band pass filter in an optical path of the LiDAR apparatus, the optical band pass filter being adapted to pass the portion of light returning to the LiDAR apparatus from the region being observed and block other light entering the band pass filter.
29. The LiDAR apparatus of claim 28 , wherein the optical band pass filter comprises one or more optical coatings formed on a component of the LiDAR apparatus.
30. The LiDAR apparatus of claim 29 , wherein the component of the LiDAR apparatus on which the one or more optical coatings are formed is the polarizing beam splitter.
31. The LiDAR apparatus of claim 29 , wherein the component of the LiDAR apparatus on which the one or more optical coatings are formed is the aperture element.
32. The LiDAR apparatus of claim 29 , wherein the component of the LiDAR apparatus on which the one or more optical coatings are formed is the at least partially reflective optical element.
33. The LiDAR apparatus of claim 29 , wherein the component of the LiDAR apparatus on which the one or more optical coatings are formed is a cover over the optical detector.