GaN Light-Emitting Element With Concave Mirror Resonator

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Solution Overview

Problem

The increase in resonator length in GaN-based compound semiconductor light-emitting elements leads to diffraction loss and heat saturation issues, hindering laser oscillation and potentially causing the element to function as an LED instead.

Innovation Solution

A light-emitting element with a laminated structure incorporating a first light reflection layer featuring a concave mirror portion and a second light reflection layer with a flat shape, along with a method of manufacturing this structure, which includes forming a base portion as a protruding concave mirror and thinning the compound semiconductor substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the resonator length is increased to improve heat dissipation in GaN-based compound semiconductor, then heat saturation is suppressed, but diffraction loss increases and laser oscillation becomes difficult

Engineering Contradiction:

Improveheat saturationVSAvoiddiffraction loss

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The patent applies a concave mirror shape to the first light reflection layer instead of a flat surface. This curvature allows the reflection layer to focus and condense diffracted light back toward the active layer, reducing diffraction loss while maintaining a compact resonator structure that improves heat dissipation.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameter of the light reflection layer from flat to concave, specifically designing a spherical concave mirror with a radius of curvature R where 10μm ≤ R ≤ 1000μm. This parameter change enables the system to achieve both reduced diffraction loss and improved heat dissipation in GaN-based compounds.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If the resonator length is increased in GaN-based compound semiconductor, then heat dissipation improves, but the element may function as an LED instead of a laser

Engineering Contradiction:

Improveheat dissipationVSAvoidlaser oscillation

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The concave mirror configuration focuses light back into the active layer, enhancing the optical feedback necessary for laser oscillation. This ensures reliable laser operation while allowing the resonator length to be optimized for heat dissipation without sacrificing laser functionality.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent converts the naturally occurring diffraction of light, which was previously a harmful loss mechanism, into a beneficial focusing effect. By using the concave mirror to recapture diffracted light and redirect it through the active layer, the system transforms diffraction loss into enhanced light-matter interaction that supports laser oscillation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If a flat light reflection layer is used, then manufacturing is simpler, but diffraction loss increases and light condensation is insufficient

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiddiffraction loss

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent introduces a concave mirror geometry that can be manufactured using standard semiconductor processing techniques such as reactive ion etching to form the curved profile, followed by deposition of reflective materials. This approach maintains manufacturing feasibility while achieving the optical performance benefits of light condensation and diffraction loss reduction.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The configuration effectively reflects and condenses diffracted light, preventing diffraction loss and heat saturation, ensuring reliable laser oscillation.

Implementation Method 1

the diffraction loss increases differently from the GaAs-based surface light-emitting laser element that employs the resonator length LOR of approximately 1 μm in the related art, and thus laser oscillation is less likely to occur

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

The first light reflection layer includes a concave mirror portion, and the second light reflection layer has a flat shape

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS20260081403A1Light-emitting element and method of manufacturing the same

Publication Date: 2026.03.19 SONY GROUP CORP

AI summary

A light-emitting element includes: a laminated structure body which is formed from a GaN-based compound semiconductor and in which a first compound semiconductor layer including a first surface and a second surface that is opposed to the first surface, an active layer that faces the second surface of the first compound semiconductor layer, and a second compound semiconductor layer including a first surface that faces the active layer and a second surface that is opposed to the first surface are laminated; a first light reflection layer that is provided on the first surface side of the first compound semiconductor layer; and a second light reflection layer that is provided on the second surface side of the second compound semiconductor layer. The first light reflection layer includes a concave mirror portion, and the second light reflection layer has a flat shape.