# US 11,909,169 B2 · Apparatus for projecting linear laser beams

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- Number: US 11,909,169 B2
- Document ID: US11909169B2
- Status: Granted
- Kind: B2
- Application number: 17/030,138
- Filed: 2020-09-23
- Published: 2021-07-08
- Granted: 2024-02-20
- Earliest claimed: 2020-01-07
- Assignees: Liturex (Guangzhou) Co. Ltd.
- Applicants: Liturex (Guangzhou) Co. Ltd
- Inventors: Yunpeng Song
- Web page: https://patentgrep.com/patent/US11909169B2

## CPC

- G02B 27/0905: {Dividing and/or superposing multiple light beams}
- H01S 5/0071: {for beam steering, e.g. using a mirror outside the cavity to change the beam direction}
- G01S 7/4815: {using multiple transmitters}
- G01S 7/4817: {relating to scanning}
- G01S 7/4865: Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak (peak detection in noise, signal conditioning G01S7/487)
- G02B 26/0833: {the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B)}
- G02B 27/0911: {Anamorphotic systems}
- H01S 5/005: {Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping (H01S5/026, H01S5/18388 take precedence)}
- H01S 5/4012: {Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms}
- H01S 5/4075: {Beam steering}
- G02B 19/0057: {in the form of a laser diode array, e.g. laser diode bar (semiconductor laser arrays with beam combining arrangement H01S5/4012)}
- G02B 26/105: {with one or more pivoting mirrors or galvano-mirrors (G02B26/101 takes precedence)}
- H01S 3/005: {Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping (shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES

## Abstract

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.

## Claims

### Claim 1

An apparatus for projecting a linear laser beam, comprising:
a laser source array;
a prism array pair;
a first cylinder lens;
a second cylinder lens; and
a microelectromechanical system (MEMS) mirror;
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; and
wherein the first cylinder lens is to focus the laser beams from the prism array pair onto the MEMS mirror, which redirects the laser beams as a linear laser beam towards a predetermined direction; and
wherein the second cylinder lens is positioned at a predetermined distance from the MEMS mirror in the predetermined direction to adjust a divergent angle of the redirected linear laser beam from the MEMS mirror.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 2)

The apparatus of claim 2, further comprising:
a cylinder lens array positioned between the plurality of FACs and the prism array pair, wherein the cylinder lens array is to convert the collimated laser beam from each laser source into a parallel laser beam along a slow axis.

### Claim 4 (depends on 3)

The apparatus of claim 3, wherein the prism array pair includes a first prism array and a second prism array that 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.

### Claim 5 (depends on 4)

The apparatus of claim 4, wherein the first prism array includes a plurality of sub-prisms, and is shaped as a plano-convex prism, with a flat surface facing the cylinder lens array to receive the collimated and parallel laser beams from the cylinder lens array.

### Claim 6 (depends on 1)

The apparatus of claim of claim 1, further comprising:
a shutter positioned before an iris to keep scattered light from the MEMS mirror.

### Claim 7 (depends on 6)

The apparatus of claim 6, wherein the iris is positioned between the shutter and the MEMS mirror to block scattered light that the shutter fails to block.

### Claim 8 (depends on 1)

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.

### Claim 9

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;
a first cylinder lens;
a second cylinder lens; and
a microelectromechanical system (MEMS) mirror;
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 the first cylinder lens is to focus the laser beams from the prism array pair onto the MEMS mirror, which redirects the laser beams as a linear laser beam towards a predetermined direction; and
wherein the second cylinder lens is positioned at a predetermined distance from the MEMS mirror in the predetermined direction to adjust a divergent angle of the redirected linear laser beam from the MEMS mirror.

### Claim 10 (depends on 9)

The LIDAR device of claim 9, 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.

### Claim 11 (depends on 10)

The LIDAR device of claim 10, wherein the laser pulse emitting unit further includes:
a cylinder lens array positioned between the plurality of FACs and the prism array pair, wherein the cylinder lens array is to convert the collimated laser beam from each laser source into a parallel laser beam along a slow axis.

### Claim 12 (depends on 11)

The LiDAR device of claim 11, wherein the prism array pair includes a first prism array and a second prism array that 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.

### Claim 13 (depends on 12)

The LiDAR device of claim 12, wherein the first prism array of the prism array pair includes a plurality of sub-prisms, and is shaped as a plano-convex prism, with a flat surface facing the cylinder lens array to receive the collimated and parallel laser beams from the cylinder lens array.

### Claim 14 (depends on 9)

The LIDAR device of claim 9, wherein the laser pulse emitting unit further includes:
a shutter positioned before an iris to keep scattered light from the MEMS mirror.

### Claim 15 (depends on 14)

The LIDAR device of claim 14, wherein the iris is positioned between the shutter and the MEMS mirror to block scattered light that the shutter fails to block.

### Claim 16 (depends on 9)

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.

### Claim 17

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 the prism array pair is positioned between the laser source and a first cylinder lens;
focusing, by the first cylinder lens, the laser beams from the prism array pair onto a microelectromechanical system (MEMS) mirror;
redirecting, by the MEMS mirror, the laser beams towards a predetermined direction as a linear laser beam towards a predetermined direction, and
adjusting, by a second cylinder lens positioned at a predetermined distance from the MEMS mirror in the predetermined direction, a divergent angle of the redirected linear laser beam from the MEMS mirror.

### Claim 18 (depends on 17)

The method of claim 17, 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.

### Claim 19 (depends on 18)

The method of claim 18, wherein a cylinder lens array positioned between the plurality of 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.

### Claim 20 (depends on 19)

The method of claim 19, wherein the prism array pair includes a first prism array and a second prism array that 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.