Prism Sheet Inclination for Moiré Suppression in Displays
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Solution Overview
Problem
Moiré patterns caused by interference between subpixels and prism sheets in liquid crystal display devices are difficult to suppress, especially when subpixels differ in shape or number within a unit pixel, leading to noticeable luminance variations and display artifacts.
Innovation Solution
Inclining the prisms in the prism sheets at specific acute angles relative to the display area, determined by ideal angles that optimize luminance uniformity for each subpixel type, and adjusting the prism pitch to match the ideal pitches of the subpixels, thereby minimizing moiré interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If prisms are arranged parallel to each other at a predetermined pitch in the prism sheet, then light concentration and display brightness are improved, but moiré patterns are generated due to interference with subpixels
Solution Approach 1:
The patent applies asymmetry by inclining the prisms at a specific angle (θ) relative to the subpixel arrangement direction, rather than arranging them parallel. This asymmetric inclination breaks the periodic interference pattern that causes moiré, while still maintaining light concentration functionality. The prisms are arranged with pitch P1 in the inclination direction and pitch P2 in the perpendicular direction, creating an asymmetric grid pattern that avoids resonance with the subpixel lattice.
Solution Approach 2:
The patent changes the geometric parameters of the prism arrangement by introducing specific pitch values (P1 and P2) and inclination angle (θ) that satisfy particular mathematical relationships. These parameter changes ensure that the prism lattice does not create periodic interference with the subpixel lattice, thereby eliminating moiré while preserving optical functionality.
2Measurement precision
If subpixels of different types have different widths, then color display accuracy is improved, but luminance uniformity deteriorates due to interference with prism shades
Solution Approach 1:
The patent applies local quality by creating different pitch values (P1 and P2) in different directional relationships to the subpixels. The pitch P1 is set in the inclination direction and P2 in the perpendicular direction, with their relationship to subpixel dimensions carefully controlled. This local differentiation in spatial parameters allows the prism array to adapt to the anisotropic subpixel structure, maintaining both color accuracy and luminance uniformity.
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
Effectively suppresses moiré patterns by aligning prisms at angles and pitches that match the optimal luminance distribution of subpixels, improving display clarity and reducing noticeable artifacts.
Implementation Method 1
When light from the light source passes through the prism sheet, the light is concentrated in a predetermined range by each of the prisms to create shades corresponding to the prisms, respectively
Implementation Method 2
These shades sometimes interfere with the subpixels in the display area to create the so-called moiré on the screen of the liquid crystal display device
Data Source
AI summary
According to one embodiment, a display device includes a display panel, a light source, a light guide and a prism sheet. The display panel includes a display area in which unit pixels each containing first sub-pixels and second sub-pixels are arranged along a first direction and a second direction. In the display area, the first sub-pixels have a width different from that of the second sub-pixel in at least one of the first direction and the second direction, or each unit pixel contains different numbers of first sub-pixels and second sub-pixels. The prism sheet is interposed between the light guide and the display panel and includes prisms extending along a third direction inclined with respect to the second direction by an acute angle of inclination.