Optical Diffusing Film for LCD Backlight Luminance
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Solution Overview
Problem
Existing optical diffusing films for LCD backlights have limited light-converging and shielding abilities due to insufficient scattering particle protrusion and coating density, resulting in inadequate luminance and uniformity of illumination.
Innovation Solution
An optical diffusing film with a transparent substrate and a diffusing coating containing spherical particles of specific diameters and mass percentages, arranged randomly, and an antiblocking coating with particles of controlled density and thickness, enhancing light-converging ability and preventing adhesion with other module elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If scattering particles of different particle sizes are randomly distributed in the coating, then light diffusion is achieved, but light-converging ability and shielding ability are limited
Solution Approach 1:
The patent applies local quality by creating different functional zones within the diffusing coating. Larger scattering particles (21-35 μm) are positioned to provide light-converging ability, while smaller particles (1-10 μm) provide light diffusion. This spatial differentiation of particle sizes within the coating structure enables simultaneous achievement of both light diffusion and light-converging functions, resolving the contradiction between illumination intensity and light-converging ability.
Solution Approach 2:
The patent uses composite materials by combining scattering particles of multiple size ranges (1-10 μm, 11-20 μm, and 21-35 μm) within the same diffusing coating. This composite particle system allows different particle sizes to perform different functions: smaller particles for diffusion and larger particles for light-converging, thereby achieving both luminance enhancement and light-converging ability.
2Reliability
If coating thickness is increased to improve light-converging ability, then shielding ability improves, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent applies parameter changes by optimizing the coating thickness to a specific range (5-20 μm) and controlling the particle size distribution parameters. By adjusting these parameters within defined ranges, the patent achieves sufficient shielding ability while maintaining manufacturability. The specific parameter ranges allow for precise control during the coating process, resolving the contradiction between shielding ability and manufacturing precision.
3Illumination intensity
If scattering particles are densely distributed to improve light diffusion, then luminance increases, but coating density control becomes more difficult
Solution Approach 1:
The patent applies local quality by creating different functional zones within the diffusing coating. Larger scattering particles (21-35 μm) are positioned to provide light-converging ability, while smaller particles (1-10 μm) provide light diffusion. This spatial differentiation of particle sizes within the coating structure enables simultaneous achievement of both light diffusion and light-converging functions, resolving the contradiction between illumination intensity and light-converging ability.
Solution Approach 2:
The patent uses composite materials by combining scattering particles of multiple size ranges (1-10 μm, 11-20 μm, and 21-35 μm) within the same diffusing coating. This composite particle system allows different particle sizes to perform different functions: smaller particles for diffusion and larger particles for light-converging, thereby achieving both luminance enhancement and light-converging ability.
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 provides higher haze and luminance with improved light-converging ability and reduced adhesion issues, resulting in enhanced performance for LCD backlights.
Implementation Method 1
the scattering particles 40 having different particle sizes are randomly distributed in the coating of the optical diffusing film produced by the conventional coating method. Incident light which incidents into the coating is sufficiently diffused mainly by the randomly distributed scattering particles 40
Implementation Method 2
a transparent substrate made of an optically transparent material with a refractive index of 1.4 to 1.8, and a diffusing coating with a refractive index of 1.4 to 1.7 disposed on an upper surface of the transparent substrate
Data Source
AI summary
An optical diffusing film and a LCD backlight using the same are provided. The optical diffusing film comprises a transparent substrate made of an optically transparent material with a refractive index of 1.4 to 1.8, and a diffusing coating with a refractive index of 1.4 to 1.7 disposed on an upper surface of the transparent substrate, wherein diffusing particles with a refractive index of 1.4 to 1.7 are distributed in the diffusing coating, and the diffusing particles are in close contact with each other, the diffusing coating has a thickness of ½ to ⅔ of the largest particle size of the diffusing particles, and the coating density of the diffusing particles is 103 to 106 particles per square millimeter.