Light-emitting Device with Hollow Particle Diffuser for Color Uniformity
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Solution Overview
Problem
Conventional light-emitting devices with phosphors exhibit uneven emission color and conspicuous phosphor color when the light-emitting surface is turned off, affecting design aesthetics, particularly in lighting fixtures.
Innovation Solution
A light-emitting device comprising a light-emitting element covered by a first and second light-transmissive member, where the second member includes a light-diffusing member with hollow particles forming irregularities on its surface, which scatters extraneous light and uniformizes the object color of the light-emitting surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a sealing resin with projecting portions is used to improve light extraction efficiency, then luminance is improved, but the phosphor color becomes visible through the light-emitting surface causing color non-uniformity
Solution Approach 1:
The patent applies local quality by introducing a light-diffusing layer with specific properties (containing hollow particles and having irregularities) at the light-emitting surface, while the underlying sealing resin maintains its projecting portions for light extraction. This localized modification addresses the color uniformity issue without compromising the luminance enhancement provided by the projecting portions.
Solution Approach 2:
The patent uses composite materials by combining the sealing resin (with projecting portions) and a light-diffusing layer (containing hollow particles and irregularities) into a multi-layer structure. This composite approach allows the bottom layer to provide luminance enhancement while the top layer ensures color uniformity, resolving the contradiction between the two functions.
2Power
If phosphor is used to generate white light, then light emission function is achieved, but the object color of the light-emitting surface becomes non-uniform when turned off
Solution Approach 1:
The patent introduces a light-diffusing layer as an intermediary between the phosphor-containing sealing resin and the external environment. This intermediary layer diffuses extraneous light and masks the phosphor color, allowing the phosphor to continue providing light emission function while preventing its color from affecting the object color uniformity of the light-emitting surface.
3Stability of the object's composition
If a light-diffusing member with hollow particles is added to the second light-transmissive member, then object color uniformity is improved, but device complexity increases
Solution Approach 1:
The patent merges the light-diffusing function with the second light-transmissive member by incorporating hollow particles and irregularities directly into this component. This integration approach combines multiple functions (light transmission and light diffusion) into a single element, improving object color uniformity while minimizing the increase in device complexity.
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 effectively scatters extraneous light, rendering the phosphor color less conspicuous and achieving a uniform object color, thereby enhancing design aesthetics and reducing luminance unevenness when the device is turned on.
Implementation Method 1
a light-diffusing member in the second light-transmissive member. The light-diffusing member comprises hollow particles
Data Source
AI summary
A light-emitting device includes: at least one light-emitting element; a first light-transmissive member covering the light-emitting element; a second light-transmissive member covering the first light-transmissive member; and a light-diffusing member in the second light-transmissive member. The light-diffusing member includes hollow particles. The second light-transmissive member has a bottom surface having irregularities due to presence of the light-diffusing member.