# US 11,442,195 B2 · Light curtain safety system

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- Number: US 11,442,195 B2
- Document ID: US11442195B2
- Status: Granted
- Kind: B2
- Application number: 17/074,488
- Filed: 2020-10-19
- Published: 2021-02-04
- Granted: 2022-09-13
- Earliest claimed: 2015-05-18
- Assignees: LaserMotive, Inc.
- Applicants: Lasermotive, Inc.
- Inventors: Jordin T. Kare; Thomas J. Nugent; David Bashford; Carsten Casey Erickson; Thomas W. Bashford
- Web page: https://patentgrep.com/patent/US11442195B2

## CPC

- G01V 8/22: using reflectors
- G01S 7/003: {Transmission of data between radar, sonar or lidar systems and remote stations}
- G01S 7/006: {using shared front-end circuitry, e.g. antennas (G01S13/765, G01S13/825 take precedence)}
- G01S 7/484: Transmitters
- G01S 17/04: Systems determining the presence of a target
- G01S 17/06: Systems determining position data of a target
- G01S 17/87: Combinations of systems using electromagnetic waves other than radio waves
- G01S 17/88: Lidar systems specially adapted for specific applications
- G01S 17/89: for mapping or imaging
- 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 5/0085: {for modulating the output, i.e. the laser beam is modulated outside the laser cavity}
- H01S 5/06216: {Pulse modulation or generation}
- H01S 5/423: {having a vertical cavity}
- H02J 50/10: using inductive coupling
- H02J 50/30: using light, e.g. lasers
- H02J 50/60: responsive to the presence of foreign objects, e.g. detection of living beings
- H02J 50/90: involving detection or optimisation of position, e.g. alignment
- H04B 10/1141: {One-way transmission}
- H04B 10/807: {Optical power feeding, i.e. transmitting power using an optical signal}
- Y02E 10/52: PV systems with concentrators
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)
- 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
- 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
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H04B: TRANSMISSION
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A system to detect obstacles includes a power beam transmission circuit, a power beam reception circuit arranged to receive a power beam from the power beam transmission circuit, an emitter module, and a detector module arranged to distinguish between a first characteristic and a second characteristic. The emitter module includes a first emitter arranged to emit a first signal having the first characteristic, the first signal emitted in proximity to the power beam, and a second emitter arranged to emit a second signal having the second characteristic, the second characteristic different from the first characteristic, the second signal emitted in proximity to the first signal. The detector module includes a first detector arranged to respond to the first signal emitted by the first emitter, wherein the detector module is arranged to determine when an obstacle is in or near a line-of-sight transmission path between the first emitter and the first detector.

## Claims

### Claim 1

A system to detect obstacles, comprising:
a power beam transmission circuit having one or more light sources to transmit a power beam;
a power beam reception circuit arranged to receive the power beam from the power beam transmission circuit;
a plurality of emitters and a plurality of detectors that form a light curtain patterned about the power beam, the plurality of emitters surrounding the power beam having an emitter module including:
a first emitter arranged to emit a first signal having a first characteristic, the first signal emitted in proximity to the power beam; and
a second emitter arranged to emit a second signal having a second characteristic, the second characteristic different from the first characteristic, the second signal emitted in proximity to the first signal; and
the plurality of detectors surrounding the power beam having a detector module arranged to distinguish between the first characteristic and the second characteristic, the detector module including:
a first detector arranged to respond to the first signal emitted by the first emitter, wherein the detector module is arranged to determine a detection of an obstacle in a line-of-sight transmission path between the first emitter and the first detector.

### Claim 2 (depends on 1)

The system according to claim 1, wherein the power beam is interrupted in response to the detection by detection module.

### Claim 3 (depends on 1)

The system according to claim 1, wherein the plurality of emitters and the plurality of detectors in the light curtain have wide fields of view that create a dense weave of optical paths that detect any object blocking an optical path in the dense weave.

### Claim 4 (depends on 1)

The system according to claim 1, wherein the detector module is arranged to detect if an object approaches the light curtain.

### Claim 5 (depends on 4)

The system according to claim 4, wherein the first characteristic includes at least one of a color, and emission wavelength, and a spectral distribution.

### Claim 6 (depends on 1)

The system according to claim 1, wherein the first signal includes at least one of a visible light signal, an infrared light signal, and an ultraviolet light signal.

### Claim 7 (depends on 1)

The system according to claim 1, wherein the first signal is a pulsed signal, and wherein the first characteristic includes a pulse rate.

### Claim 8 (depends on 1)

The system according to claim 1, wherein the first signal is a synchronized signal, and wherein the first characteristic includes synchronized timing.

### Claim 9 (depends on 1)

The system according to claim 1, wherein the first signal is a modulated signal, and wherein the first characteristic includes a modulation frequency.

### Claim 10 (depends on 1)

The system according to claim 1, wherein the first signal is an encoded light signal, the encoded light signal modulated with a signal code, and wherein the first characteristic includes a representation of the signal code.

### Claim 11 (depends on 1)

The system according to claim 1, wherein the line-of-sight transmission path includes one or more reflective structures, each of the one or more reflective structures arranged to re-direct signals that reach said reflective structure.

### Claim 12

A method of detecting obstacles, comprising:
transmitting a power beam from one or more light sources using a power beam transmission circuit;
receiving the power beam from the power beam transmission circuit using a power beam reception circuit;
forming a light curtain patterned about the power beam using a plurality of emitters and a plurality of detectors, the plurality of emitters surrounding the power beam having an emitter module including a first emitter and a second emitter, the plurality of detectors surrounding the power beam having a detector module arranged to distinguish between the first characteristic and the second characteristic, the detector module including a first detector;
emitting a first signal having a first characteristic from the first emitter, the first signal emitted in proximity to the power beam;
emitting a second signal having a second characteristic from the second emitter, the second characteristic different from the first characteristic, the second signal emitted in proximity to the first signal; and
determining, by the detector module, a detection of an obstacle in a line-of-sight transmission path between the first emitter and the first detector.

### Claim 13 (depends on 12)

The method according to claim 12, wherein the power beam is interrupted in response to the detection by detection module.

### Claim 14 (depends on 12)

The method according to claim 12, wherein the plurality of emitters and the plurality of detectors in the light curtain have wide fields of view that create a dense weave of optical paths that detect any object blocking an optical path in the dense weave.

### Claim 15 (depends on 12)

The method according to claim 12, wherein the detector module is arranged to detect if an object approaches the light curtain.

### Claim 16 (depends on 12)

The method according to claim 12, wherein the first signal is a pulsed signal, and wherein the first characteristic includes a pulse rate.

### Claim 17 (depends on 12)

The method according to claim 12, wherein the first signal is a synchronized signal, and wherein the first characteristic includes synchronized timing.

### Claim 18 (depends on 12)

The method according to claim 12, wherein the first signal is a modulated signal, and wherein the first characteristic includes a modulation frequency.

### Claim 19 (depends on 12)

The method according to claim 12, wherein the first signal is an encoded light signal, the encoded light signal modulated with a signal code, and wherein the first characteristic includes a representation of the signal code.

### Claim 20

A system to detect obstacles, comprising:
a power beam transmission circuit having one or more light sources to transmit a power beam;
a power beam reception circuit arranged to receive the power beam from the power beam transmission circuit;
a plurality of emitters and a plurality of detectors that form a light curtain patterned about the power beam;
the plurality of emitters surrounding the power beam having an emitter module including: a first emitter arranged to emit a first signal having a first characteristic; and a second emitter arranged to emit a second signal having a second characteristic, the second characteristic different from the first characteristic; and
the plurality of detectors surrounding the power beam having a detector module arranged to distinguish between the first characteristic and the second characteristic;
wherein the plurality of emitters and the plurality of detectors in the light curtain have wide fields of view that create a dense weave of optical paths that detect any object blocking an optical path in the dense weave.