Surface-Emitting LED Sealing Layer for Thin Uniform Luminance
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Solution Overview
Problem
Conventional surface-emitting devices, such as downlight type system LED backlights, face challenges in achieving in-plane uniformity of luminance while reducing thickness, due to luminance unevenness caused by pins or spacers used to maintain the gap between LED elements and diffusion members.
Innovation Solution
A surface-emitting device is designed with a sealing member having a haze value of 4% or more and a thickness greater than the LED element, placed between the LED element and the diffusion member, using a thermoplastic resin and a specific structure to improve light diffusion and reduce module thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If pins or spacers are placed to maintain the gap between LED element and diffusion member, then the gap distance is maintained, but luminance unevenness occurs due to light blocking or reflection
Solution Approach 1:
The invention removes the pins or spacers from the optical path between the LED element and the diffusion member. By extracting these obstructive components, the light can travel unobstructed, eliminating the luminance unevenness caused by light blocking or reflection while maintaining the necessary gap distance through alternative means.
Solution Approach 2:
The invention introduces a refractive index adjustment layer as an intermediary substance between the LED element and the diffusion member. This layer has a refractive index that is optimized to reduce reflection and improve light extraction efficiency, thereby maintaining the gap distance while preventing luminance unevenness caused by optical interference.
2Length of stationary object
If diffusion member is placed close to LED element to reduce thickness, then module thickness is reduced, but luminance uniformity deteriorates
Solution Approach 1:
The invention changes the refractive index parameter of the medium between the LED element and the diffusion member by introducing a refractive index adjustment layer. This parameter change optimizes light extraction and diffusion characteristics, allowing the diffusion member to be placed closer to the LED element while maintaining luminance uniformity across the display surface.
3Manufacturing precision
If additional diffusion plate is placed on upper side of transmission reflector to improve luminance uniformity, then in-plane uniformity is improved, but module thickness increases
Solution Approach 1:
The invention makes the refractive index adjustment layer serve multiple functions simultaneously: it maintains the gap distance between the LED element and diffusion member, reduces reflection losses, improves light extraction efficiency, and ensures luminance uniformity. This multi-functionality eliminates the need for additional diffusion plates, thereby improving in-plane uniformity without increasing module thickness.
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 enhances in-plane uniformity of luminance and reduces the thickness of the surface-emitting device, addressing the limitations of conventional designs by optimizing the refractive index difference and light diffusion properties.
Implementation Method 1
a haze value of the sealing member is 4% or more
Data Source
AI summary
A surface-emitting device includes: a light-emitting diode substrate including a supporting substrate, and a light-emitting diode element placed on one surface side of the supporting substrate; a sealing member placed on a light-emitting diode element side surface of the light-emitting diode substrate, and configured to seal the light-emitting diode element; and a diffusion member placed on the sealing member, on an opposite surface side to the light-emitting diode substrate side, wherein a haze value of the sealing member is 4% or more, and a thickness thereof is thicker than a thickness of the light-emitting diode element.