Light-emitting device with segmented wavelength conversion for color uniformity
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Solution Overview
Problem
There is a demand for light-emitting devices with improved color mixing and reduced color non-uniformity of emitted light, as existing technologies do not fully achieve these goals.
Innovation Solution
A light-emitting device comprising a base member with first and second light-emitting elements, first and second wavelength conversion members, where the first wavelength conversion members consist of a light-transmissive body with an inorganic material and a phosphor layer, and the second wavelength conversion member covers both light-emitting elements and wavelength conversion members, utilizing an encapsulating resin with phosphors to enhance color mixing and reduce non-uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a first encapsulating material containing a yellow phosphor covers blue LED chips and a red light-emitting unit is constituted by covering a near-ultraviolet LED chip with a material containing a red phosphor, then color mixing is improved and color non-uniformity is reduced, but further improvement in color mixing and reduction in color non-uniformity is still needed
Solution Approach 1:
The wavelength conversion members are divided into multiple types: first wavelength conversion members (with blue LEDs and yellow phosphor) and second wavelength conversion members (with red LEDs and red phosphor). These segmented units are arranged in a specific pattern to achieve uniform color distribution across the entire light-emitting surface, preventing color non-uniformity while maintaining effective color mixing.
Solution Approach 2:
Different regions of the light-emitting device have different local compositions: first wavelength conversion members are disposed at specific positions with blue LEDs and yellow phosphors, while second wavelength conversion members are disposed at other positions with red LEDs and red phosphors. This local differentiation ensures that each region contributes appropriately to the overall color uniformity and mixing quality.
2Stability of the object's composition
If wavelength conversion members are disposed on light-emitting elements to improve color mixing, then color non-uniformity is reduced, but device complexity increases
Solution Approach 1:
Multiple functional components are merged into integrated wavelength conversion members. Each wavelength conversion member combines a light-emitting element, phosphor materials, and encapsulating resin into a single unified structure. This merging approach achieves uniform color distribution without requiring separate complex assembly of multiple independent components.
Solution Approach 2:
The wavelength conversion members serve multiple functions simultaneously: they convert wavelength (phosphor function), provide structural support and protection (encapsulating resin function), and enable uniform color distribution through their specific arrangement. This multi-functionality reduces the need for additional separate components, thereby managing 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 described configuration improves color mixing and reduces color non-uniformity by utilizing the refractive index difference between inorganic materials and resin, scattering light effectively and achieving uniform phosphor distribution, thereby producing a desired emission color with enhanced wavelength conversion efficiency.
Implementation Method 1
a first phosphor layer on the lower surface of the light-transmissive body
Implementation Method 2
The first wavelength conversion members each comprises a light-transmissive body mainly containing an inorganic material, and a first phosphor layer on the lower surface of the light-transmissive body
Implementation Method 3
The second wavelength conversion member comprises an encapsulating resin and second phosphor
Implementation Method 4
The second wavelength conversion member is disposed on the base member to cover the second light-emitting elements and the first wavelength conversion members
Implementation Method 5
utilizing the refractive index difference between inorganic materials and resin, scattering light effectively
Data Source
AI summary
A light-emitting device comprising: a base member; a plurality of first light-emitting elements disposed on the base member; a plurality of second light-emitting elements disposed on the base member; a plurality of first wavelength conversion members; and a second wavelength conversion member. The first wavelength conversion members are respectively disposed on or above the first light-emitting elements. The first wavelength conversion members each comprises a light-transmissive body mainly containing an inorganic material, and a first phosphor layer on the lower surface of the light-transmissive body. The second wavelength conversion member is disposed on the base member to cover the second light-emitting elements and the first wavelength conversion members. The second wavelength conversion member comprises an encapsulating resin and second phosphor.