OPTICAL SCANNING ELEMENT SUBMERGED IN LIGHT-TRANSMISSIVE FLUID

1 . A system comprising:

a movable optical element configured to direct light along an optical path;

a flat surface along the optical path, the light from the movable optical element passing through the flat surface to an external environment; and

a light-transmissive fluid that is present along the optical path, the light-transmissive fluid and the flat surface having a substantially same optical index.

2 . The system of claim 1 , further comprising:

a light source to emit the light; and

one or more static optical element to direct the light along an initial optical path;

wherein the movable optical element is configured to receive the light from the initial optical path and to redirect the light along optical path.

3 . The system of claim 1 , wherein the external environment has an optical index that is less than the optical index of the light-transmissive fluid and the flat surface.

4 . The system of claim 3 , wherein the movable optical element has an optical index that is greater than the optical index of the light-transmissive fluid and the flat surface.

5 . The system of claim 4 , wherein the movable optical element has an optical index that is 0.4 or more greater than the optical index of the light-transmissive fluid and the flat surface.

6 . The system of claim 1 , wherein the wherein the light-transmissive fluid comprises oil.

7 . The system of claim 6 , wherein the light-transmissive fluid comprises silicon oil.

8 . The system of claim 1 , wherein the light-transmissive fluid has a light transmissibility of 95% or more.

9 . The system of claim 1 , wherein the flat surface comprises glass.

10 . The system of claim 1 , wherein the flat surface comprises at least one of polycarbonate, polymer, or clear acrylic.

11 . The system of claim 1 , wherein the movable optical element comprises an optical scanning element having a glass body in the shape of a rectangular prism, wherein the optical scanning element is configured to rotate around an axis, and wherein the optical scanning element comprises a reflective member having opposing reflective surfaces within the glass body.

12 . The system of claim 11 , wherein the optical scanning element comprises one or more magnets; and

wherein the system comprises coils that are controllable to generate one or more magnetic fields that interact with the one or more magnets to control rotation of the optical scanning element.

13 . The system of claim 1 , wherein the movable optical element is configured to receive the light from an initial optical path at a first side thereof and to redirect the light along the optical path from a second side thereof, the first side being behind the second side.

14 . The system of claim 1 , which is part of a light detection and ranging (LIDAR) system for a vehicle.

15 . The system of claim 13 , wherein the LIDAR system is configured for use in at least one of: automatic emergency breaking for the vehicle, forward sensing for the vehicle, or automated driving for the vehicle.

16 . The system of claim 1 , wherein the flat surface comprises an anti-reflective coating.

17 . The system of claim 1 , wherein the movable optical element is completely submerged in the light-transmissive fluid.

18 . The system of claim 1 , wherein the movable optical element is partially submerged in the light-transmissive fluid.

19 . The system of claim 1 , wherein the movable optical element is configured to direct light along multiple optical paths; and

wherein the light-transmissive fluid is present along the multiple optical paths.

20 . The system of claim 1 , wherein the external environment comprises air.