Light-emitting Device Resin Member Lateral Surface Light Control
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Solution Overview
Problem
Light-emitting devices with hemispherical lens members exhibit uneven luminance due to hemispherical light distribution, leading to differences in luminance between regions directly above and between light-emitting elements, and result in increased thickness and cost, making it difficult to achieve a reduction in device thickness.
Innovation Solution
A light-emitting device with a substrate and light sources where the light-emitting elements have electrodes on their surface facing the substrate, and a resin member covering the lateral surfaces but not the upper surface, achieving a variation in light output of 15% or less within a 40° range, thereby reducing luminance unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hemispherical lens members are used to seal light-emitting elements, then the light-emitting elements are protected and sealed, but luminance unevenness occurs between regions directly above and between adjacent light-emitting elements
Solution Approach 1:
The invention divides the light extraction function into two separate components: the hemispherical lens member for sealing and protection, and the resin member for light distribution control. This segmentation allows each component to perform its specific function optimally without compromising the other, resolving the contradiction between sealing protection and luminance uniformity
Solution Approach 2:
The resin member acts as an intermediary between the light-emitting element and the external environment, controlling light distribution and reducing luminance unevenness while allowing the hemispherical lens member to focus on sealing and protection functions
2Reliability
If hemispherical lens members are used to seal light-emitting elements, then sealing is achieved, but the distance between the mounting board and diffuser must be greater than the thickness of lens members, increasing device thickness
Solution Approach 1:
The invention segments the sealing and light distribution functions into separate components, allowing the use of thinner hemispherical lens members for sealing while adding a thin resin member for light control, thereby reducing overall device thickness compared to using thick single-component lens members
Solution Approach 2:
The invention changes the thickness parameter of the hemispherical lens member by using a thinner design that is sufficient for sealing purposes, and compensates for the reduced light distribution function by adding the resin member, achieving both reduced thickness and maintained sealing effectiveness
3Device complexity
If conventional light-emitting elements with hemispherical light distribution are used, then the structure is simple, but luminance unevenness occurs making it difficult to achieve high-definition images
Solution Approach 1:
The invention segments the light distribution control function from the basic light-emitting structure by adding a separate resin member, maintaining the simplicity of the light-emitting element itself while achieving the complex light distribution control needed for high-definition images
Solution Approach 2:
The resin member serves as an intermediary that transforms the hemispherical light distribution into a more uniform pattern, enabling high-definition image quality without requiring complex modifications to the light-emitting element structure
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 reduces luminance unevenness and allows for a thinner light-emitting device design while maintaining high-definition image capabilities and cost-effectiveness by using a resin member to direct light emitted from the lateral surfaces upward.
Implementation Method 1
a resin member covering lateral surfaces of the light-emitting element and not covering an upper surface of the light-emitting element
Data Source
AI summary
A light-emitting device includes: a substrate; and at least one light source comprising: a light-emitting element comprising a plurality of electrodes that face the substrate, and a resin member covering at least portions of lateral surfaces of the light-emitting element and not covering an upper surface of the light-emitting element, wherein, in a directivity diagram of the light source, a variation in light output of the light source in a range of −40° to 40° is 15% or less.