Planar Light Source Peripheral Brightness Uniformity
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Solution Overview
Problem
Planar light sources with irregular shapes experience uneven brightness at their peripheral regions due to the absence of light sources in areas near the outer edges, leading to dark spots and reduced light extraction efficiency.
Innovation Solution
A planar light source design incorporating a mounting substrate with light sources arranged in a matrix, a partition member with wall portions surrounding each light source, and a light diffusion plate with a thin peripheral region to reduce brightness unevenness, where the light diffusion plate has a thin plate portion adjacent to the peripheral region to enhance light extraction and reduce diffusion frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light sources are arranged in a regular grid pattern on the mounting substrate, then the manufacturing process is simple and easy, but brightness unevenness occurs at the peripheral region of irregularly shaped planar light sources
Solution Approach 1:
The patent applies local quality by varying the arrangement and density of light sources in different regions of the mounting substrate. Specifically, the peripheral region contains fewer or no light sources compared to the central region, creating a non-uniform distribution that compensates for the irregular shape of the planar light source. This localized adjustment of light source density resolves the brightness unevenness at the periphery while maintaining overall manufacturing simplicity.
2Ease of manufacture
If a light diffusion plate with uniform thickness is used, then the manufacturing process is simple, but light extraction efficiency is reduced at the peripheral region
Solution Approach 1:
The patent implements local quality by creating a light diffusion plate with variable thickness, where the peripheral region has a thinner profile compared to the central region. This thickness variation is specifically designed to enhance light extraction efficiency at the periphery, where the reduced thickness allows for better light emission and reduced total internal reflection. The manufacturing process accommodates this variation through techniques such as injection molding or machining, balancing complexity with performance improvement.
3Strength
If the light diffusion plate has a thick peripheral region to maintain structural integrity, then mechanical strength is improved, but brightness unevenness and light extraction efficiency deteriorate
Solution Approach 1:
The patent employs the principle of flexible shells and thin films by utilizing a thin peripheral region in the light diffusion plate that maintains sufficient structural integrity through careful design. The thin peripheral portion is engineered to provide the necessary mechanical strength while simultaneously enabling enhanced light extraction and reduced brightness unevenness. This approach balances structural requirements with optical performance by optimizing the thickness profile rather than uniformly thickening the entire plate.
Solution Approach 2:
The patent applies local quality by differentiating the thickness of different regions of the light diffusion plate. The central region maintains a greater thickness for structural support, while the peripheral region is intentionally thinned to improve light extraction efficiency and reduce brightness unevenness. This localized differentiation allows the structure to meet both mechanical strength requirements and optical performance targets simultaneously.
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 design effectively reduces brightness unevenness and increases light extraction at the peripheral region, improving the overall uniformity and efficiency of the planar light source by prioritizing light transmission over diffusion in the thin plate portion.
Implementation Method 1
a wavelength conversion member, and a light diffusion plate. The wavelength conversion member is disposed on the lateral wall of the frame body
Implementation Method 2
The light diffusion plate contains diffusion particles for diffusing light emitted from light emitting portions of the light emitting elements
Data Source
AI summary
A planar light source includes a mounting substrate, a plurality of light sources, a partition member, a frame body, a wavelength conversion member, and a light diffusion plate. The light sources are arranged two-dimensionally on the mounting substrate in a plan view. The partition member includes a wall portion surrounding each of the light sources except for outermost ones of the light sources in the plan view. The wall portions are located inward of the outermost ones of the light sources. The frame body has a bottom portion and a lateral wall surrounding the mounting substrate. The wavelength conversion member is disposed on the lateral wall of the frame body. The light diffusion plate is disposed above the plurality of light sources and the wavelength conversion member.