Semiconductor Light-Emitting Device Recess for Wide-Angle Dispersion

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Solution Overview

Problem

Semiconductor light-emitting devices face challenges in achieving wide light dispersion and luminous efficiency, particularly in converting light emitted from the light-emitting layer using phosphors, as most of the light is concentrated in the layer stack direction, limiting their application in devices requiring broader light distribution.

Innovation Solution

The semiconductor light-emitting device incorporates a recess in the outer periphery of the light-emitting member, which extends inwardly to expose an inner surface facing the side surface, allowing for improved light extraction and dispersion by reflecting light between the side and inner surfaces, and utilizing dielectric and metal layers to enhance light reflection and extraction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If light is emitted from the light-emitting layer in the layer stack direction, then high luminance is achieved in that direction, but light dispersion in directions crossing the layer stack direction is limited

Engineering Contradiction:

Improveluminance in layer stack directionVSAvoidlight dispersion in crossing directions

Core Design Contradiction:

Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a recess structure that extends in the depth direction (perpendicular to the layer stack direction) to create a third dimension for light extraction. By forming the recess to a specific depth and configuring its inner surface, light can be extracted not only in the layer stack direction but also in directions crossing the layer stack direction, achieving wide-angle light emission and improving light dispersion characteristics.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of energy

If phosphors are arranged near the sides of the light-emitting member for wavelength conversion, then luminous efficiency is improved, but light extraction from the side surface remains insufficient

Engineering Contradiction:

Improveluminous efficiencyVSAvoidlight extraction from side surface

Core Design Contradiction:

Loss of energyVSIllumination intensity

Solution Approach 1:

The patent applies local quality by configuring the recess structure with specific geometric parameters (depth, width, and inner surface orientation) at the side surface region where phosphors are arranged. This localized structural optimization enhances light extraction efficiency specifically at the side surface, allowing phosphors to be effectively excited while improving overall luminous efficiency without compromising light emission intensity.

Inventive Principle:

Principle #3Local quality

3Illumination intensity

If a recess is formed to extend inwardly to expose an inner surface facing the side surface, then light radiation from the side surface is increased, but device complexity increases

Engineering Contradiction:

Improvelight radiation from side surfaceVSAvoidstructural complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent segments the light-emitting member by forming a recess that divides the structure into distinct regions (outer peripheral region and inner region). This segmentation allows independent optimization of light extraction at the side surface through the recess while maintaining the overall integrity of the device, achieving enhanced light radiation without excessive complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of adding external structures to enhance side surface light extraction, the patent inverts the approach by removing material to form a recess. This subtraction-based design simplifies the overall structure while effectively increasing light radiation from the side surface by creating an internal reflective surface.

Inventive Principle:

Principle #13The other way round (Inversion)

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

This design significantly increases light radiation from the side surface, widens the area of light dispersion, and improves luminous efficiency by reducing light concentration on the front surface, thereby enhancing the light dispersion characteristics of the semiconductor light-emitting device.

Implementation Method 1

allowing for improved light extraction and dispersion by reflecting light between the side and inner surfaces

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 2

utilizing dielectric and metal layers to enhance light reflection and extraction efficiency

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS10403790B2Method for manufacturing semiconductor light-emitting device

Publication Date: 2019.09.03 ALPAD CORP

AI summary

A semiconductor light-emitting device includes a light-emitting member that includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light-emitting layer between the first semiconductor layer and the second semiconductor layer, a first metal layer electrically connected to the first semiconductor layer, and a second metal layer electrically connected to the second semiconductor layer. The light-emitting member has a first surface including a front surface of the first semiconductor layer, a second surface including a front surface of the second semiconductor layer, a side surface including an outer periphery of the first semiconductor layer, and a recess extending inwardly of the second surface to an interior portion of the first semiconductor layer to expose an inner surface on a side of the recess facing the side surface.