# US 12,216,378 B2 · Projection device and projection method

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- Number: US 12,216,378 B2
- Document ID: US12216378B2
- Status: Granted
- Kind: B2
- Application number: 18/282,045
- Filed: 2022-02-10
- Published: 2024-02-08
- Granted: 2025-02-04
- Earliest claimed: 2021-03-22
- Assignees: NEC Corporation
- Applicants: NEC Corporation
- Inventors: Koya Takata; Hisashi Mizumoto; Fujio Okumura
- Web page: https://patentgrep.com/patent/US12216378B2

## CPC

- G02F 1/29: for the control of the position or the direction of light beams, i.e. deflection
- G02F 1/01: for the control of the intensity, phase, polarisation or colour (G02F1/29, G02F1/35 take precedence)
- G02F 1/13: based on liquid crystals, e.g. single liquid crystal display cells
- G03B 21/005: {Projectors using an electronic spatial light modulator but not peculiar thereto}
- H04B 10/11: Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
- G02F 1/1336: {Illuminating devices}
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- H04B: TRANSMISSION

## Abstract

A projection device a includes a light source that emits parallel light, a spatial light modulator that has a modulation part that modulates a phase of the parallel light emitted from the light source, a liquid crystal projection lens that includes a liquid crystal region on which modulated light modulated by the spatial light modulator is incident and that projects the modulated light in a lens region dynamically formed in the liquid crystal region as projection light, and a control unit that causes the lens region to be formed at a desired position in the liquid crystal region of the liquid crystal lens, sets a phase image corresponding to the projection light projected toward a projection target, to the modulation part of the spatial light modulator, and controls the light source to emit the parallel light toward the modulation part to which the phase image is set.

## Claims

### Claim 1

A projection device comprising:
a light source configured to emit parallel light;
a spatial light modulator that has a modulation part that modulates a phase of the parallel light emitted from the light source;
a liquid crystal lens that includes a liquid crystal region on which modulated light modulated by the spatial light modulator is incident and that projects the modulated light incident on a lens region dynamically formed in the liquid crystal region as projection light; and
a controller including:
a memory storing instructions; and
a processor connected to the memory and configured to execute the instructions to:
cause the lens region to be formed at a desired position in the liquid crystal region of the liquid crystal lens;
set a phase image corresponding to the projection light projected toward a projection target, to the modulation part of the spatial light modulator; and
control the light source to emit the parallel light toward the modulation part to which the phase image is set,
wherein the light source is configured to switch between modulation schemes of the parallel light to be emitted, and
wherein the processor is configured to execute the instructions to switch between the modulation schemes of the parallel light to be emitted from the light source in accordance with a use purpose.

### Claim 2 (depends on 1)

The projection device according to claim 1, wherein the processor is configured to execute the instructions to control a projection direction of the projection light by two-dimensionally moving the position where the lens region is formed in the liquid crystal region of the liquid crystal lens.

### Claim 3 (depends on 1)

The projection device according to claim 1, wherein the processor is configured to execute the instructions to control a projection angle of the projection light by adjusting a refractive index of the lens region formed in the liquid crystal region of the liquid crystal lens.

### Claim 4 (depends on 1)

The projection device according to claim 1, wherein the processor is configured to execute the instructions to cause a plurality of the lens regions to be formed in the liquid crystal region of the liquid crystal lens.

### Claim 5 (depends on 4)

The projection device according to claim 4, wherein the processor is configured to execute the instructions to:
cause the plurality of the lens regions different in at least one of the projection direction and the projection angle of the projection light to be formed in the liquid crystal region of the liquid crystal lens;
individually set a plurality of the phase images corresponding to the projection light projected toward the different projection targets, to a plurality of modulation regions set to the modulation part of the spatial light modulator, in association with the plurality of the lens regions; and
control the light source to emit the parallel light toward the modulation part in which the different phase images are set to the plurality of modulation regions.

### Claim 6 (depends on 5)

The projection device according to claim 5, further comprising a plurality of the light sources arranged to emit the parallel light toward the different modulation regions,
wherein the processor is configured to execute the instructions to control each of the plurality of light sources to emit the parallel light toward the modulation part in which the different phase images are set to the plurality of modulation regions.

### Claim 7 (depends on 1)

The projection device according to claim 1, further comprising an imaging unit configured to image the projection direction of the projection light,
wherein the processor is configured to execute the instructions to control at least one of the projection direction and the projection angle of the projection light in accordance with a position of the projection target included in an image captured by the imaging unit.

### Claim 8 (depends on 1)

The projection device according to claim 1, further comprising a light receiving element that receives light coming from the projection direction of the projection light,
wherein the processor is configured to execute the instructions to control at least one of the projection direction and the projection angle of the projection light in accordance with the light received by the light receiving element.

### Claim 9

A projection method for controlling a projection device including a light source configured to emit parallel light, a spatial light modulator that has a modulation part that modulates a phase of the parallel light emitted from the light source, and a liquid crystal lens that includes a liquid crystal region on which modulated light modulated by the spatial light modulator is incident and that projects the modulated light incident on a lens region dynamically formed in the liquid crystal region as projection light, the method comprising:
causing the lens region to be formed at a desired position in the liquid crystal region of the liquid crystal lens;
setting a phase image corresponding to the projection light projected toward a projection target, to the modulation part of the spatial light modulator, and
controlling the light source to emit parallel light toward the modulation part to which the phase image is set,
wherein the light source is configured to switch between modulation schemes of the parallel light to be emitted, and
wherein the method further comprises switching between the modulation schemes of the parallel light to be emitted from the light source in accordance with a use purpose.