Planar Light Source Structure for Uniform Batwing Light Distribution
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Solution Overview
Problem
Existing planar light sources suffer from luminance unevenness due to variations in light distribution, which affects the quality and uniformity of lighting.
Innovation Solution
A planar light source design incorporating a light-emitting device with a wavelength conversion member, a light-transmissive member, and reflective members, where the thickness of the light-transmissive member is greater than the wavelength conversion member, and the light distribution characteristics are optimized to achieve a batwing light distribution pattern with reduced luminance unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional light-emitting device structure is used, then the device is simple to manufacture, but luminance unevenness occurs in the light distribution
Solution Approach 1:
The light-emitting device is segmented into multiple functional layers: a light-emitting element, a wavelength conversion member with specific thickness, and a light-transmissive member with greater thickness. This segmentation allows each layer to perform its specific function optimally, with the light-transmissive member specifically designed to reduce luminance unevenness by having a thickness greater than the wavelength conversion member.
Solution Approach 2:
The patent applies local quality by making the light-transmissive member have a specific thickness relationship (greater than the wavelength conversion member) to address the local issue of luminance unevenness. The light-transmissive member is positioned specifically to cover the wavelength conversion member and modify the light distribution characteristics in the lateral direction.
2Illumination intensity
If the light-transmissive member thickness is increased to reduce luminance unevenness, then light distribution uniformity improves, but device thickness increases
Solution Approach 1:
The patent optimizes the thickness parameters of the wavelength conversion member and light-transmissive member to achieve the desired light distribution. By carefully controlling the thickness relationship (light-transmissive member thickness greater than wavelength conversion member thickness) and the lateral surface exposure, the device achieves improved luminance uniformity while minimizing the overall thickness increase.
3Illumination intensity
If the lateral surface of the wavelength conversion member is exposed to achieve batwing light distribution, then light distribution characteristic improves, but chromaticity deviation may increase
Solution Approach 1:
The light-transmissive member acts as an intermediary between the wavelength conversion member and the external environment. It covers the upper surface of the wavelength conversion member while allowing the lateral surface to remain exposed, mediating the light extraction process to achieve batwing light distribution while maintaining chromaticity uniformity through its optical properties.
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 significantly reduces luminance unevenness and chromaticity deviations, resulting in a more uniform and efficient light distribution, allowing for thinner and lighter lighting fixtures with improved performance.
Implementation Method 1
a wavelength conversion member disposed on an upper surface and a lateral surface of the element portion
Implementation Method 2
a light-transmissive member disposed on an upper surface of the wavelength conversion member and including a light-diffusing material
Implementation Method 3
a first light reflective member disposed on the lower surface of the element portion and a lower surface of the wavelength conversion member
Data Source
AI summary
The planar light source includes a light-emitting device including a light-emitting element provided with an element portion and an electrode disposed on a lower surface of the element portion, a wavelength conversion member disposed on an upper surface and a lateral surface of the element portion, a light-transmissive member disposed on an upper surface of the wavelength conversion member, and a first light reflective member disposed on lower surfaces of the element portion and the wavelength conversion member; a substrate; and a second light reflective member disposed on an upper surface of the substrate and provided with an opening. The light-emitting device is disposed on the upper surface of the substrate in the opening, and the upper surface of the substrate includes an exposed portion exposed from the light-emitting device in the opening. A thickness of the light-transmissive member is larger than a thickness of the wavelength conversion member.