Laser Diode Light-Emitting Device with Segmented Wavelength Conversion

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Solution Overview

Problem

Conventional light-emitting devices using laser diodes or LEDs face challenges in enhancing luminance and efficiently outputting light due to limitations in wavelength conversion and light distribution, leading to potential color irregularities and reduced luminous efficiency.

Innovation Solution

A light-emitting device design featuring a support body with a laser diode, a cylindrical reflector, and a cap containing a wavelength conversion member, where the cap's shape and positioning are optimized to match the cross-sectional beam pattern of the emitted light, and optionally includes a convergent lens and thermal conductive member to enhance light conversion and output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a wavelength conversion member is used to convert monochromatic light from a laser diode, then light of different wavelengths can be emitted, but the luminance and luminous efficiency are limited due to conversion losses

Engineering Contradiction:
ImproveluminanceVSAvoidwavelength conversion loss
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The wavelength conversion member is divided into multiple regions with different fluorescent substances, each converting light to different wavelengths. This segmentation allows optimized light extraction from each region, improving overall luminance while managing conversion losses through regional specialization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the wavelength conversion member have different properties (different fluorescent substances) to optimize local light conversion and extraction. This local quality variation ensures that each region contributes maximally to the overall luminance output.

Inventive Principle:
Principle #3Local quality

2Strength

If a thick glass wavelength conversion member is used to ensure mechanical strength, then structural integrity is improved, but light extraction efficiency is reduced due to increased absorption and scattering

Engineering Contradiction:
Improvemechanical strengthVSAvoidlight extraction efficiency
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The thickness of the wavelength conversion member is optimized to balance mechanical strength and light extraction efficiency. By carefully controlling the thickness parameter, the design achieves sufficient structural integrity while minimizing light absorption and scattering losses.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a simple cap structure is used to cover the reflector, then device complexity is reduced, but uniform wavelength conversion and light extraction cannot be achieved

Engineering Contradiction:
Improvestructure complexityVSAvoiduniformity of wavelength conversion
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The cap structure incorporates a wavelength conversion member with multiple regions, each having different properties. This segmentation enables uniform wavelength conversion across the entire structure while maintaining a relatively simple overall design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cap structure serves multiple functions: it covers the reflector, provides structural support, and enables uniform wavelength conversion through its multi-region design. This multi-functionality achieves precision without proportionally increasing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Device complexity

If monochromatic light from laser diode is emitted directly, then the light source is simple and compact, but color variety and white light emission are not achieved

Engineering Contradiction:
Improvelight source structureVSAvoidcolor emission capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The wavelength conversion member uses composite fluorescent substances in different regions to convert monochromatic light into multiple wavelengths. This composite approach enables color variety and white light emission while maintaining a simple laser diode light source structure.

Inventive Principle:
Principle #40Composite materials

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 configuration significantly improves luminance by ensuring uniform wavelength conversion and efficient light extraction, reducing color irregularities and enhancing the overall luminous efficiency of the light-emitting device.

Implementation Method 1

a wavelength conversion member for emitting light having a wavelength different from that of light emitted by the light-emitting element

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

a cylindrical reflector fixed to the support body and provided with a light reflection surface on its inner surface surrounding the light-emitting element

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3540794B1Light-emitting device
Publication Date: 2022.03.30 NICHIA CORP
  • EP3540794B1 patent drawingFigure 1A~1B
  • EP3540794B1 patent drawingFigure 2A~2B
  • EP3540794B1 patent drawingFigure 3~5

AI summary

Disclosed is that, in a semiconductor light-emitting device, light from a laser diode is output to the outside after the luminance of the light being enhanced. The light-emitting device includes a support body 11; a wavelength conversion member (133) mounted on the support body 11; and a light-emitting element 12, wherein the light is made directly incident on the wavelength conversion member 133 obliquely below the light-emitting element 12 and the wavelength conversion member 133 receives a peak intensity of irradiation by the light-emitting element 12 and emits light different in wavelength from light emitted by the light-emitting element 12 when the light-emitting element 12 emits the light, and the light emitted by the wavelength conversion member 133 is output upward above the support body 11.