# US 11,442,353 B2 · Virtual image projection device

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- Number: US 11,442,353 B2
- Document ID: US11442353B2
- Status: Granted
- Kind: B2
- Application number: 17/215,251
- Filed: 2021-03-29
- Published: 2021-12-02
- Granted: 2022-09-13
- Earliest claimed: 2020-05-29
- Assignees: Hitachi-LG Data Storage, Inc.
- Applicants: Hitachi-LG Data Storage, Inc.
- Inventors: Takahiro Mouri; Ryuji Ukai; Takuma Kuno; Toshiteru Nakamura
- Web page: https://patentgrep.com/patent/US11442353B2

## CPC

- G03B 21/208: {Homogenising, shaping of the illumination light}
- G02B 3/0056: {arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses (G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085)}
- G02B 27/017: {Head mounted}
- 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)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A virtual image projection device that generates image light includes a light source that emits light; a microlens array that emits the light, which is emitted from the light source, as light having a predetermined angle distribution; an imaging lens that concentrates the light from the microlens array; a display unit that is irradiated with the light, which is concentrated by the imaging lens, to generate an image; and a projection unit that projects the image, which is generated by the display unit, as image light. The microlens array is disposed such that short side directions of lens cells do not line up straight.

## Claims

### Claim 1

A virtual image projection device that generates image light, the device comprising:
a light source that emits light;
a microlens array that emits the light, which is emitted from the light source, as light having a predetermined angle distribution;
an imaging lens that concentrates the light from the microlens array;
a display unit that is irradiated with the light, which is concentrated by the imaging lens, to generate an image;
a projection unit that projects the image, which is generated by the display unit, as image light; and
a light guide unit that guides the image light projected from the projection unit,
wherein the microlens array is disposed such that short side directions of lens cells do not line up straight, and
wherein the microlens array is disposed such that the short side directions of the lens cells coincide with a propagation direction of the light guide unit.

### Claim 2

A virtual image projection device that generates image light, the device comprising:
a light source that emits light;
a microlens array that emits the light, which is emitted from the light source, as light having a predetermined angle distribution;
an imaging lens that concentrates the light from the microlens array;
a display unit that is irradiated with the light, which is concentrated by the imaging lens, to generate an image; and
a projection unit that projects the image, which is generated by the display unit, as image light,
wherein the microlens array is such that lens cells are aligned vertically and horizontally, and a value of an aspect ratio of the lens cells is set between a value of an aspect ratio of a light emitting region shape of the light source and a value of an aspect ratio of the projected image projected by the projection unit.

### Claim 3 (depends on 2)

The virtual image projection device according to claim 2,
wherein the aspect ratio of the light emitting region shape of the light source is 1:1, and
the value of the aspect ratio of the lens cells of the microlens array is an aspect ratio that is closer to 1 than a value of a ratio of 16:9.

### Claim 4 (depends on 2)

The virtual image projection device according to claim 2,
wherein the microlens array is disposed such that short side directions of the lens cells do not line up straight.

### Claim 5 (depends on 2)

The virtual image projection device according to claim 2,
wherein the microlens array is such that short side directions of the lens cells are disposed in a staggered manner.

### Claim 6 (depends on 2)

The virtual image projection device according to claim 2,
wherein the microlens array is such that short side directions of the lens cells are disposed to be shifted from each other over a plurality of stages.

### Claim 7 (depends on 4)

The virtual image projection device according to claim 4, further comprising:
a light guide unit that guides the image light projected from the projection unit,
wherein the microlens array is disposed such that the short side directions of the lens cells coincide with a propagation direction of the light guide unit.

### Claim 8 (depends on 5)

The virtual image projection device according to claim 5, further comprising:
a light guide unit that guides the image light projected from the projection unit,
wherein the microlens array is disposed such that the short side directions of the lens cells coincide with a propagation direction of the light guide unit.

### Claim 9 (depends on 6)

The virtual image projection device according to claim 6, further comprising:
a light guide unit that guides the image light projected from the projection unit,
wherein the microlens array is disposed such that the short side directions of the lens cells coincide with a propagation direction of the light guide unit.