Light Emitting Device Segmented Phosphor Structure
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Solution Overview
Problem
Light emitting devices used in vehicle components require even higher luminance than existing technologies can provide, necessitating an enhancement in light source design for directional and luminous efficiency.
Innovation Solution
A light emitting device comprising a light emitting element, a first light transmissive member with a first phosphor, a second light transmissive member with a second phosphor, and a light reflective member, where the first transmissive member is in contact with the upper surface of the light emitting element and has a smaller area, and the second transmissive member covers lateral surfaces and part of the upper surface, with the light reflective member covering lateral surfaces of both transmissive members to achieve high luminance and luminous flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single light transmissive member is used to cover the light emitting element, then the structure is simple, but the luminance and color uniformity are insufficient for vehicle lighting applications
Solution Approach 1:
The light transmissive member is divided into two separate members: a first light transmissive member covering the central region and a second light transmissive member covering the peripheral region. This segmentation allows each member to be optimized for its specific function, with the first member providing high luminance in the center and the second member ensuring uniform color distribution at the edges, thereby achieving both high luminance and color uniformity without excessive structural complexity.
Solution Approach 2:
Different regions of the light emitting device are assigned different optical properties through the two light transmissive members. The first light transmissive member is designed with properties optimized for high luminance output in the central region, while the second light transmissive member is designed with properties optimized for color uniformity in the peripheral region. This local optimization of quality allows the device to achieve high overall luminance and color uniformity simultaneously.
2Illumination intensity
If the light transmissive member area is reduced to increase luminance concentration, then luminance intensity increases, but color non-uniformity increases
Solution Approach 1:
The coverage area is segmented between two light transmissive members: the first member covers the central region where high luminance intensity is required, while the second member covers the peripheral region where color uniformity is critical. This spatial segmentation allows the central region to concentrate light for high intensity without compromising the peripheral region's color uniformity, as each region is independently optimized by its respective member.
Solution Approach 2:
Different optical qualities are applied to different spatial locations: the first light transmissive member in the central region is optimized for light concentration and intensity, while the second light transmissive member in the peripheral region is optimized for color uniformity. This local differentiation of quality allows the system to achieve high luminance intensity in the center while maintaining color uniformity across the entire emission area.
3Productivity
If lateral surfaces are left uncovered to maintain structural simplicity, then manufacturing is easier, but light extraction efficiency and luminance are reduced
Solution Approach 1:
The second light transmissive member serves multiple functions simultaneously: it covers the lateral surfaces of the first light transmissive member, it covers the peripheral region of the light emitting element, and it contributes to color uniformity. By merging these multiple functions into a single component, the design achieves improved light extraction efficiency and luminance without proportionally increasing the number of components, as the second member integrates several structural and optical roles.
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 configuration results in a high-luminance light emitting device with clear luminance and color uniformity, suitable for vehicle lighting applications by enhancing light extraction efficiency and reducing color non-uniformity and luminance differences.
Implementation Method 1
The first light transmissive member contains a first phosphor
Implementation Method 2
The second light transmissive member contains a second phosphor
Implementation Method 3
The light reflective member covers lateral surfaces of the second light transmissive member and lateral surfaces of the light emitting element
Data Source
AI summary
A light emitting device includes a light emitting element, a first light transmissive member, a second light transmissive member, and a light reflective member. The first light transmissive member contains a first phosphor. The first light transmissive member is in contact with an upper surface of the light emitting element, and has an area smaller than the light emitting element in a plan view. The second light transmissive member contains a second phosphor. The second light transmissive member covers lateral surfaces of the first light transmissive member and a part of the upper surface of the light emitting element that is exposed from the first light transmissive member, with an upper surface of the first light transmissive member being not covered by the second light transmissive member. The light reflective member covers lateral surfaces of the second light transmissive member and lateral surfaces of the light emitting element.