Optical Sheet Prism Patterns Moiré Reduction
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Solution Overview
Problem
Liquid crystal displays (LCDs) suffer from a moiré phenomenon due to interference between the periodic patterns of prism sheets and pixel pitches, leading to reduced display quality and visibility of wave patterns.
Innovation Solution
An optical sheet with prism patterns inclined at a specific angle and diffusion patterns overlapping the pixels, which weaken the periodicity of the brightness pattern, is used in conjunction with a manufacturing method involving a roller with recesses to form the diffusion patterns on a base sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a prism sheet with periodic prism patterns is used to guide light, then light guidance efficiency is improved, but moiré phenomenon occurs due to interference with pixel pitches
Solution Approach 1:
The patent applies asymmetry by inclining the prism patterns at a specific angle (θ) of 10 to 70 degrees relative to the pixel arrangement direction, breaking the periodic symmetry that causes moiré interference. This asymmetric orientation disrupts the regular interference pattern between the prism sheet and pixel grid while maintaining effective light guidance through the inclined prism structures.
Solution Approach 2:
The patent introduces a new dimensional parameter by adding diffusion patterns at multiple levels (first diffusion patterns at peaks, second diffusion patterns at valleys) on top of the inclined prism patterns. This multi-level structural arrangement in the vertical dimension creates complex light scattering paths that eliminate the periodic interference causing moiré while preserving light guidance functionality.
2Manufacturing precision
If diffusion patterns are added to reduce moiré, then display quality is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functions into a single integrated optical sheet structure. The inclined prism patterns and multi-level diffusion patterns are combined in one sheet, with first diffusion patterns at peaks and second diffusion patterns at valleys. This unified structure achieves moiré reduction and light guidance simultaneously, avoiding the need for separate optical components and simplifying the overall manufacturing process.
Solution Approach 2:
The patent applies local quality by positioning different diffusion patterns at specific locations: first diffusion patterns are placed at the peaks of inclined prism patterns, while second diffusion patterns are placed at the valleys. Each region has optimized properties for its specific function, creating localized light scattering zones that collectively eliminate moiré interference while maintaining manufacturing feasibility.
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 reduces the moiré effect, improving display quality by varying the brightness and reducing periodic interference, while allowing for a slim display panel design without compromising light collection efficiency.
Implementation Method 1
The first surface is pressed by the roller
Implementation Method 2
The base sheet may be cured by ultraviolet rays
Implementation Method 3
The recesses of the roller may be formed by using a laser
Implementation Method 4
The prism sheet includes a prism pattern of which peaks and valleys are alternately disposed
Implementation Method 5
a plurality of diffusion patterns arranged at the peaks and valleys, and which overlap the pixels at a predetermined interval
Data Source
AI summary
A display apparatus includes a display panel and a backlight unit for an embodiment. The display panel includes a plurality of pixels and the backlight unit supplies light to the display panel. The backlight unit includes a light source, which generates the light, and an optical sheet. The optical sheet includes a plurality of prism patterns formed on a surface of the optical sheet facing the display panel. The prism patterns include a plurality of peaks and a plurality of valleys to change the path of the light, and a plurality of diffusion patterns arranged at the peaks and valleys.