Reflective Light Conversion Structure for Uniform LED Luminance
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Solution Overview
Problem
Existing semiconductor light emitting devices suffer from color unevenness and luminance loss due to light emission from side surfaces, leading to reduced luminous flux and luminance, especially in high-luminance applications, and are prone to thermal stress and reliability issues when integrated.
Innovation Solution
A light emitting apparatus with a light transparent member and a covering member that reflects light from side surfaces to the emission surface, using an inorganic material with a light reflective coating to enhance luminance and reduce color unevenness, and includes a flip-chip mounting of light emitting devices for improved heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light emitting devices are integrated to increase luminous flux, then total light output increases, but color unevenness and luminance loss worsen due to side surface emission
Solution Approach 1:
The patent extracts and removes the harmful side surface emission by covering the side surfaces of the light transparent member with a light absorbing member. This isolates the unwanted light emission from the system, allowing the front surface to maintain uniform color characteristics while preserving increased luminous flux from multiple integrated light emitting devices.
Solution Approach 2:
The patent applies different properties to different parts of the light transparent member: the front surface maintains light transmission for uniform color emission, while the side surfaces are covered with light absorbing material to prevent color unevenness. This local differentiation resolves the contradiction between total light output and color uniformity.
2Productivity
If side surfaces are left exposed for light extraction, then luminous flux increases, but luminance and color uniformity deteriorate
Solution Approach 1:
The patent converts the harmful side surface emission into a beneficial configuration by strategically placing light absorbing members on side surfaces. This prevents scattered light from degrading luminance and color uniformity, while the front surface continues to provide high luminance output. The harmful side emission is transformed into a controlled optical path that benefits overall performance.
3Productivity
If multiple light emitting devices are integrated, then total light output increases, but thermal stress and reliability issues worsen
Solution Approach 1:
The patent segments the optical system into distinct functional zones: front surfaces for light emission, side surfaces for light absorption and thermal management, and rear surfaces for device mounting. This segmentation allows heat from multiple integrated light emitting devices to be managed separately through the side surface absorbing members, preventing thermal accumulation and improving reliability while maintaining high light output.
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 solution enhances luminance and reduces color unevenness by directing light emission primarily from the emission surface, improving luminous flux and heat dissipation, resulting in a high-luminance and reliable light source with uniform luminance distribution.
Implementation Method 1
The covering member contains a light reflective material, and covers at least the side surface of the light transparent member
Data Source
AI summary
A light emitting apparatus includes: a mount substrate; a light emitting device located above the mount substrate, the light emitting device having a lateral surface; a light conversion member located above the light emitting device, the light conversion member having a lateral surface located outward of the lateral surface of the light emitting device in a top plan view; and a covering member that contains a light reflective material and covers the lateral surface of the light conversion member.