# US 12,113,334 B2 · Light emitting device and projector

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- Number: US 12,113,334 B2
- Document ID: US12113334B2
- Status: Granted
- Kind: B2
- Application number: 17/361,222
- Filed: 2021-06-28
- Published: 2021-12-30
- Granted: 2024-10-08
- Earliest claimed: 2020-06-30
- Assignees: Seiko Epson Corporation; Sophia School Corporation
- Applicants: Seiko Epson Corporation; Sophia School Corporation
- Inventors: Shunsuke Ishizawa; Katsumi Kishino
- Web page: https://patentgrep.com/patent/US12113334B2

## CPC

- H01S 5/11: Comprising a photonic bandgap structure
- G03B 21/2033: {LED or laser light sources}
- H01S 5/1042: {Optical microcavities, e.g. cavity dimensions comparable to the wavelength}
- H01S 5/32341: {blue laser based on GaN or GaP}
- H01S 5/42: Arrays of surface emitting lasers
- H01S 5/04257: {having positive and negative electrodes on the same side of the substrate}
- H01S 5/1021: {Coupled cavities (H01S5/14 takes precedence)}
- H01S 5/1032: {Coupling to elements comprising an optical axis that is not aligned with the optical axis of the active region}
- H01S 5/185: having only horizontal cavities, e.g. horizontal cavity surface-emitting lasers [HCSEL] (comprising a photonic bandgap structure H01S5/11)
- 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
- 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)

## Abstract

A light emitting device includes a substrate, and a stacked body provided to the substrate, and including a plurality of first columnar parts, wherein the stacked body includes a first semiconductor layer, a second semiconductor layer different in conductivity type from the first semiconductor layer, and a light emitting layer disposed between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer and the light emitting layer constitute the first columnar parts, the first semiconductor layer is disposed between the substrate and the light emitting layer, the second semiconductor layer is provided with a plurality of recessed parts, the recessed part is provided with a low refractive-index part lower in refractive index than the second semiconductor layer, a plurality of the first columnar parts constitutes a first photonic crystal, the second semiconductor layer and the low refractive-index parts constitute a second photonic crystal, and the first photonic crystal and the second photonic crystal are optically coupled to each other.

## Claims

### Claim 1

A light emitting device comprising:
a substrate; and
a stacked body provided to the substrate, and including a plurality of first columnar parts, wherein
the stacked body includes
a first semiconductor layer,
a second semiconductor layer different in conductivity type from the first semiconductor layer, and
a light emitting layer disposed between the first semiconductor layer and the second semiconductor layer,
the first semiconductor layer and the light emitting layer constitute the first columnar parts,
the first semiconductor layer is disposed between the substrate and the light emitting layer,
the second semiconductor layer is provided with a plurality of recessed parts,
the recessed part is provided with a low refractive-index part lower in refractive index than the second semiconductor layer,
the plurality of the first columnar parts constitutes a first photonic crystal,
the second semiconductor layer and the low refractive-index parts constitute a second photonic crystal, and
the first photonic crystal and the second photonic crystal are optically coupled to each other,
wherein the second semiconductor layer has a portion disposed so as to straddle the plurality of the first columnar parts.

### Claim 2 (depends on 1)

The light emitting device according to claim 1, wherein
the optical distance between the first photonic crystal and the second photonic crystal is no more than 3λ (λ is an lasing wavelength).

### Claim 3 (depends on 1)

The light emitting device according to claim 1, wherein
the first columnar parts and the low refractive-index parts overlap in a plan view.

### Claim 4 (depends on 3)

The light emitting device according to claim 3, wherein
the first columnar parts and the low refractive-index parts correspond one-to-one to each other.

### Claim 5 (depends on 3)

The light emitting device according to claim 3, wherein
a diametrical size of the recessed part is smaller than a diametrical size of the first columnar part.

### Claim 6 (depends on 1)

The light emitting device according to claim 1, wherein
the second semiconductor layer constitutes a plurality of second columnar parts, and
the first columnar parts and the second columnar parts overlap in a plan view.

### Claim 7 (depends on 1)

A projector comprising:
the light emitting device according to claim 1.