Laminate Sheet Gloss Ratio for LCD Sparkle Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional liquid crystal display devices experience issues with sparkle occurrence due to interference between the shape of reflective polarizing sheets and pixel pitch, and lack of uniformity in luminance caused by other optical members, especially with advancements in miniaturization.
Innovation Solution
A laminate sheet with a three-layer structure comprising an intermediate layer and two matte layers, where the ratio of gloss at 60° of the back face of the second matte layer to the front face of the first matte layer is between 3/2 and 10, and the first matte layer has a gloss at 60° between 5 and 20, to effectively diffuse light and reduce sparkle interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a reflective polarizing sheet is disposed between the liquid crystal panel and optical sheets, then light utilization efficiency is improved, but sparkle occurrence increases due to interference between the sheet shape and pixel pitch
Solution Approach 1:
A diffusion sheet is introduced as an intermediary layer between the reflective polarizing sheet and the liquid crystal panel. This diffusion sheet scatters light before it reaches the reflective polarizing sheet, preventing the formation of sparkle patterns caused by direct interference between the polarizing sheet structure and pixel pitch, while still allowing the reflective polarizing sheet to function in improving light utilization efficiency
Solution Approach 2:
The invention changes the optical parameters of the system by introducing a diffusion sheet with specific haze and transmittance characteristics. This modifies the light distribution parameters to reduce sparkle occurrence while maintaining adequate light utilization efficiency through controlled diffusion
2Illumination intensity
If diffusion sheets are laminated on the front and back faces of a reflective polarizer, then luminance uniformity is improved, but sparkle occurrence increases due to interference with pixel pitch
Solution Approach 1:
The invention applies different surface treatments to different locations of the diffusion sheet. The front surface has a specific roughness to control light scattering, while the back surface has different characteristics to manage light entry. This local differentiation allows luminance uniformity improvement without excessive sparkle generation
Solution Approach 2:
The invention optimizes specific parameters of the diffusion sheet including surface roughness (Ra: 0.03-0.5μm), haze (5-80%), and transmittance (80-95%). These parameter adjustments balance the competing requirements of luminance uniformity and sparkle reduction
3Manufacturing precision
If the pixel pitch of the liquid crystal panel is miniaturized, then display resolution is improved, but sparkle occurrence increases due to interference with the reflective polarizer shape
Solution Approach 1:
The diffusion sheet serves as a mediator that decouples the interaction between the reflective polarizing sheet structure and the miniaturized pixel pitch. By scattering light before it encounters the reflective polarizing sheet, the diffusion sheet prevents the formation of sparkle patterns that would otherwise be exacerbated by smaller pixel dimensions
Solution Approach 2:
The invention adjusts the optical parameters of the diffusion sheet to compensate for the effects of miniaturized pixel pitch. The specific haze and surface roughness parameters are optimized to maintain sparkle reduction effectiveness across different pixel pitch scales
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 laminate sheet inhibits sparkle occurrence and reduces luminance uniformity issues by diffusing light appropriately, enhancing the utilization efficiency of light and maintaining face luminance.
Implementation Method 1
A laminate sheet, a liquid crystal display module, a backlight unit, and a production method of a laminate sheet that enable inhibition of the occurrence of sparkles caused by the interference with the pixel pitch of the liquid crystal panel while reducing the lack in uniformity of luminance caused by the shape of other optical member disposed on a back face side
Data Source
AI summary
A laminate sheet includes an intermediate layer, a first matte layer laminated on a front face side of the intermediate layer, and a second matte layer laminated on a back face side of the intermediate layer. A ratio of a gloss at 60° of a back face of the second matte layer to a gloss at 60° of a front face of the first matte layer is no less than 3/2 and no greater than 10. The gloss at 60° of the front face of the first matte layer is preferably no less than 5 and no greater than 20. The gloss at 60° of the back face of the second matte layer is preferably no less than 30 and no greater than 80. An arithmetic average roughness of the front face of the first matte layer is preferably no less than 0.5 μm and no greater than 1 μm.