Prism Sheet with Diffusion Particles for Moiré-Free Backlight
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Solution Overview
Problem
Liquid crystal displays face challenges in achieving high brightness without developing moiré patterns, and existing solutions with fine prism pitches suffer from brightness deterioration and manufacturing difficulties.
Innovation Solution
A backlight unit with a prism sheet featuring a light-transmissive resin base material, diffusion particles, and linear prisms with a pitch of 32 μm to 36 μm, designed to collimate light and improve thermal resistance and mechanical strength, preventing moiré patterns while maintaining high brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the prism pitch is reduced to prevent moiré patterns, then the moiré pattern is suppressed, but the brightness deteriorates and manufacturing becomes difficult
Solution Approach 1:
The patent applies parameter changes by optimizing the prism pitch to a specific range (30-40 μm) and controlling the prism height (5-20 μm) to achieve the right balance between preventing moiré patterns and maintaining brightness. This quantitative parameter optimization resolves the contradiction by finding the optimal values that satisfy both requirements.
Solution Approach 2:
The patent uses composite material structures by combining a base film with a protective layer containing diffusion particles, and integrating prisms with specific pitch and height ratios. This composite approach allows simultaneous achievement of moiré pattern prevention and brightness maintenance through material composition rather than solely relying on geometric parameters.
2Object-generated harmful factors
If the prism pitch is reduced to prevent moiré patterns, then the moiré pattern is suppressed, but the manufacturing precision requirement increases
Solution Approach 1:
The patent resolves the manufacturing precision contradiction by establishing a practical pitch range (30-40 μm) that is manufacturable while still effective for moiré prevention. By providing a range rather than a single precise value, the patent makes the specification achievable in industrial manufacturing while maintaining the moiré suppression effect.
Solution Approach 2:
The patent applies partial action by using a slightly larger pitch range (30-40 μm) than the theoretical minimum, which provides a buffer for manufacturing variations. This partial approach ensures that even with manufacturing tolerances, the prisms will effectively prevent moiré patterns without requiring extreme precision.
3Stability of the object's composition
If a protective layer with diffusion particles is added to improve brightness uniformity, then the brightness uniformity is improved, but the light transmission is reduced
Solution Approach 1:
The patent applies local quality by strategically placing diffusion particles only in the protective layer while keeping the base film and prism structures optimized for light transmission. The diffusion particles are distributed at specific concentrations (5-20 wt%) and sizes (1-10 μm) to provide localized brightness uniformity enhancement without excessively blocking light across the entire optical path.
Solution Approach 2:
The patent resolves the light transmission contradiction by optimizing multiple parameters of the protective layer: diffusion particle concentration (5-20 wt%), particle size (1-10 μm), and layer thickness. By coordinating these parameters, the protective layer achieves sufficient brightness uniformity while maintaining acceptable light transmission levels.
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 effectively enhances brightness and viewing angle without moiré patterns, offering improved thermal resistance and mechanical strength, thus addressing the limitations of existing technologies.
Implementation Method 1
The prism sheet 5 refracts the light emitted from the diffuser sheet 4 in a low angle to collimate the light toward the front direction
Implementation Method 2
The diffuser sheet 4 scatters the light to make the brightness uniform and widen the viewing angle
Implementation Method 3
The light guide plate 3 mixes the light input through the light incidence surface disposed at its side surface and emits the mixed light through the light emitting surface
Data Source
AI summary
The present invention relates to a liquid crystal display having excellent brightness without moiré patterns. The present invention also relates to a prism sheet and backlight unit which may improve the brightness of the liquid crystal display while removing the moiré patterns. A prism sheet comprises a protective layer including a base material consisting of a light-transmissive resin; and a plurality of diffusion particles distributed in the protective layer to scatter the light input into the base material; a base film disposed on a surface of the protective layer, wherein the light emitted from the protective layer is input into the base film; and a plurality of linear prisms having a pitch of between about 32 μm and about 38 μm and disposed in parallel on a surface of the base film.