Apparatus for projecting linear laser beams
In one embodiment, described herein is an apparatus for projecting linear illumination fanned out along the slow axis of a laser source array. In addition to the laser source array, the apparatus can include a number of fast axis collimators (FACs) to collimate the laser beams from the laser source array along the fast axis, a cylinder lens array for converting the collimated laser beams to parallel laser beams, and a prism array pair for reducing the pitch of the parallel laser beams. The system further includes a first cylinder lens for focusing the laser beams from the prism array pair onto a MEMS mirror, which redirects the laser beams as a linear laser beam towards a predetermined direction.
1. An apparatus comprising:
a laser source array;
a prism array pair; and
a first cylinder lens;
wherein the prism array pair is positioned between the laser source array and the first cylinder lens to reduce a pitch between laser beams from the laser source array to a predetermined value, wherein a first prism array of the prism array pair is shaped as a piano-convex prism with a flat surface to receive collimated and parallel laser beams from a cylinder lens array; and
wherein the first cylinder lens is to focus the laser beams from the prism array pair onto a microelectromechanical system (MEMS) mirror, which redirects the laser beams as a linear laser beam towards a predetermined direction.
2. The apparatus of claim 1 , further comprising:
a plurality of fast axis collimators (FACs), wherein each FAC is coupled with one of a plurality of laser sources in the laser source array to collimate a laser beam from the laser source along a fast axis.
3. The apparatus of claim 2 , wherein the cylinder lens array is positioned between the plurality of FACs and the prism array pair to convert the collimated laser beam from the laser source into a parallel laser beam along a slow axis.
4. The apparatus of claim 3 , wherein the first prism array and a second prism array of the prism array pair are separated by a spacing, wherein the spacing is based on a reduction of the pitch of the laser beams from the laser source array.
5. The apparatus of claim 1 , further comprising: a shutter positioned before an iris to keep scattered light from the MEMS mirror.
6. The apparatus of claim 5 , wherein the iris is positioned between the shutter and the MEMS mirror to block scattered light that the shutter fails to block.
7. The apparatus of claim 1 , wherein the laser source array includes a plurality of laser sources, wherein each laser source includes a plurality of laser diodes, and is driven by a same voltage, or a different voltage.
8. A light detection and ranging (LiDAR) device that includes a laser pulse emitting unit, wherein the laser pulse emitting unit further includes:
a laser source array;
a prism array pair; and
a first cylinder lens;
wherein the prism array pair is positioned between the laser source array and the first cylinder lens to reduce a pitch between laser beams from the laser source array to a predetermined value, wherein a first prism array of the prism array pair is shaped as a piano-convex prism with a flat surface to receive collimated and parallel laser beams from a cylinder lens array; and
wherein the first cylinder lens is to focus the laser beams from the prism array pair onto a microelectromechanical system (MEMS) mirror, which redirects the laser beams as a linear laser beam towards a predetermined direction.
9. The LIDAR device of claim 8 , wherein the laser pulse emitting unit further includes:
a plurality of fast axis collimators (FACs), wherein each FAC is coupled with one of a plurality of laser sources in the laser source array to collimate a laser beam from the laser source along a fast axis.
10. The LIDAR device of claim 9 , wherein:
the cylinder lens array is positioned between the plurality of FACs and the prism array pair to convert the collimated laser beam from each laser source into a parallel laser beam along a slow axis.
11. The LiDAR device of claim 10 , wherein the first prism array and a second prism array of the prism array pair are separated by a spacing, wherein the spacing is based on a reduction of the pitch of the laser beams from the laser source array.
12. The LIDAR device of claim 9 , wherein the lase pulse emitting unit further includes:
a shutter positioned before an iris to keep scattered light from the MEMS mirror.
13. The LIDAR device of claim 12 , wherein the iris is positioned between the shutter and the MEMS mirror to block scattered light that the shutter fails to block.
14. The LiDAR device of claim 9 , wherein the laser source array includes a plurality of laser sources, wherein each laser source includes a plurality of laser diodes, and is driven by a same voltage, or a different voltage.
15. A method of projecting a linear laser beam, comprising:
reducing, using a prism array pair, a pitch of laser beams generated by a laser source array to a predetermined value, wherein a first prism array of the prism array pair is shaped as a plano-convex prism with a flat surface to receive collimated and parallel laser beams from a cylinder lens array;
focusing the laser beams from the prism array pair onto a microelectromechanical system (MEMS) mirror; and
redirecting, by the MEMS mirror, the laser beams towards a predetermined direction as a linear laser beam towards a predetermined direction.
16. The method of claim 15 , wherein the laser source array includes a plurality of laser sources, each laser source including a plurality of laser diodes packaged together, wherein each laser source is coupled with a fast axis collimator (FAC), which is to collimate a laser beam from the laser source along a fast axis.
17. The method of claim 15 , wherein a cylinder lens array positioned between a plurality of fast axis collimator (FACs) and the prism array pair is configured to convert the collimated laser beam from each laser source into a parallel laser beam along a slow axis.
18. The method of claim 16 , wherein a laser pulse emitting unit further includes:
a shutter positioned before an iris to keep scattered light from the MEMS mirror.
19. The method of claim 18 , wherein the iris is positioned between the shutter and the MEMS mirror to block scattered light that the shutter fails to block.
20. The method of claim 16 , wherein the laser source array includes a plurality of laser sources, wherein each laser source includes a plurality of laser diodes, and is driven by a same voltage, or a different voltage.