Liquid Crystal Display Prism Sheet Moire Fringe Elimination
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Solution Overview
Problem
Liquid crystal display apparatuses with prism sheets between a surface light source and a liquid crystal display device suffer from moire fringes due to differences in prism pitch and pixel pitch, which degrade display quality.
Innovation Solution
Incorporating a liquid crystal display apparatus with a prism sheet, a first diffusion layer with a specific haze value, and a second diffusion layer with a different haze value, both on polarizing plates, along with viewing angle compensation films, to condense and diffuse light effectively, preventing moire fringes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a prism sheet is arranged between the surface light source and the liquid crystal display device to improve luminance, then display luminance is improved, but moire fringes appear due to interference between prism pitch and pixel pitch
Solution Approach 1:
A diffusion layer is introduced as an intermediary element between the prism sheet and the liquid crystal display device. This diffusion layer scatters the light waves, disrupting the regular interference pattern that causes moire fringes while preserving the overall light transmission and luminance enhancement provided by the prism sheet.
Solution Approach 2:
The invention changes the optical parameters of the system by introducing a diffusion layer with specific haze values (first haze value and second haze value). This modification alters the light propagation characteristics, reducing the coherence of light waves that would otherwise interfere to produce moire patterns, while maintaining sufficient light intensity for high luminance display.
2Object-affected harmful factors
If a diffusion layer with high haze value is used to prevent moire fringes, then moire fringes are reduced, but display contrast deteriorates
Solution Approach 1:
The invention applies diffusion layers with different haze values at different locations: a first diffusion layer with a first haze value positioned closer to the prism sheet, and a second diffusion layer with a second haze value positioned closer to the liquid crystal display device. This local differentiation allows each layer to perform its specific function - the first layer primarily reduces moire fringes while the second layer maintains display contrast.
Solution Approach 2:
The invention uses a composite structure of multiple diffusion layers with different optical properties (different haze values) rather than a single uniform diffusion layer. This composite approach enables the system to simultaneously achieve moire fringe reduction and contrast maintenance by combining the effects of layers with complementary characteristics.
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 enhances display luminance and quality by eliminating moire fringes and maintaining high contrast, with the first diffusion layer's larger haze value and the second's smaller haze value effectively diffusing light to prevent interference.
Implementation Method 1
a prism sheet which is arranged between the surface light source and the liquid crystal display device and has a plurality of elongated prisms which are formed in parallel with each other to condense irradiation light from the surface light source to enter the liquid crystal display device
Implementation Method 2
a first diffusion layer which is provided on a surface side of the surface-light-source-side polarizing plate facing the surface-light-source-side substrate and has a first haze value; and a second diffusion layer which is provided on a surface of the surface-light-source-side polarizing plate facing the surface light source and has a second haze value different from the first haze value
Data Source
AI summary
A liquid crystal display apparatus includes a liquid crystal display device, a surface light source for emitting illumination light toward the liquid crystal display device, and a prism sheet which is arranged between the surface light source and the liquid crystal display device. The liquid crystal display device includes an observation-side substrate and a surface-light-source-side substrate. A liquid crystal layer is interposed between the substrates. First and second electrodes are provided on at least one of inner surfaces of the substrates and apply an electric field to the liquid crystal layer. Observation-side and surface-light-source-side polarizing plates are arranged to sandwich the substrates therebetween. First and second diffusion layers having different haze values are respectively provided on opposite surface sides of the surface-light-source-side polarizing plate.