Optical Sheet Pitch and Diffuser Haze for LCD Moire Prevention
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Solution Overview
Problem
Liquid crystal displays (LCDs) face challenges in preventing moiré interference between the prism arrangement pitch of optical sheets and the pixel pitch of the LCD panel, which leads to a decrease in front luminance and image quality.
Innovation Solution
Optimizing the characteristics of a diffuser sheet, including its haze value and total light transmittance, and determining the upper limit of the irregularity pitch of the optical sheet based on the pixel pitch of the LCD panel to ensure the ratio (H/Tt)·(Pp/P) is greater than or equal to 1.6, thereby preventing moiré and maintaining luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the prism arrangement pitch is narrowed to prevent moiré, then moiré interference is reduced, but front luminance decreases significantly
Solution Approach 1:
A diffuser sheet is introduced as an intermediary component between the optical sheet and the liquid crystal display panel. This diffuser sheet has specific optical characteristics (haze value H and total light transmittance Tt) that allow it to scatter the light from the prisms effectively, preventing the periodic interference patterns (moiré) while maintaining sufficient light intensity to achieve high front luminance. The diffuser sheet acts as a mediator that decouples the moiré prevention function from the luminance maintenance function.
2Object-affected harmful factors
If a diffuser sheet is arranged between the prism sheet and liquid crystal display panel to prevent moiré, then moiré interference is reduced, but light beams condensed by prisms cannot be effectively utilized
Solution Approach 1:
The invention specifies precise parameter ranges for the diffuser sheet to optimize its performance: the haze value H should be in the range of 20-80% and the total light transmittance Tt should be in the range of 70-90%. By controlling these parameters, the diffuser sheet achieves the right balance between scattering light sufficiently to prevent moiré and transmitting enough light to maintain high front luminance and effective utilization of the condensed light beams from theprisms.
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
This approach effectively prevents moiré occurrence while enhancing front luminance and image quality by optimizing the diffuser sheet's characteristics and pitch arrangement in the optical sheet, ensuring improved performance across various LCD panel sizes.
Implementation Method 1
The haze value H indicates the degree of diffusion; the larger the value of H, the greater the light diffusion effect, and hence the greater the degree to which the periodicity of the distribution of light emerging from the condenser sheet is mitigated.
Implementation Method 2
a prism sheet has a large number of prisms having a triangular cross section arranged on the light-emergent side surface, and causes light incident on the prism sheet to be refracted by and transmitted through the slopes of the prisms, thereby condensing the light into the front direction.
Data Source
AI summary
A liquid crystal display, optical sheet manufacturing method, and an optical sheet are provided. The occurrence of moiré is prevented while suppressing a reduction in front luminance. The liquid crystal display includes: a liquid crystal display panel; a light source arranged on a back surface side of the liquid crystal display panel; an optical sheet with a light-condensing property arranged between the liquid crystal display panel and the light source, the optical sheet having a number of irregularities arranged continuously on a principal surface of the optical sheet; and a diffuser sheet arranged between the liquid crystal display panel and the optical sheet. The liquid crystal display is constructed so that when an arrangement pitch of the irregularities of the optical sheet is P [μm], a haze value of the diffuser sheet is H [%], a total light transmittance of the diffuser sheet is Tt [%], and a pixel pitch of the liquid crystal display panel is Pp [μm], the following relationship is satisfied: (H/Tt)·(Pp/P)≧1.6.