Striped Diffuser for LCD Viewing Angle Control
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Solution Overview
Problem
Liquid crystal display (LCD) devices have a narrow viewing angle due to differences in optical paths for vertically and obliquely passing light, leading to increased manufacturing costs and image blurring risks when attempting to adjust viewing angles for privacy and public modes.
Innovation Solution
A diffuser with alternating diffusing and transparent areas, manufactured using a transparent resin with diffusing particles, is integrated into the LCD device, allowing for adjustable viewing angles by controlling light transmission through the liquid crystal layer, with the diffuser's design ensuring similar luminance in both modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a PDLC layer is used to adjust viewing angle, then viewing angle adjustment capability is improved, but manufacturing cost increases
Solution Approach 1:
The diffuser is segmented into alternating transparent areas and diffusing areas with different light transmission properties. This segmentation allows the display to achieve different viewing angles by controlling which areas are active, providing viewing angle adjustment capability without requiring a PDLC layer.
Solution Approach 2:
Different areas of the diffuser have different optical properties - transparent areas allow light to pass through while diffusing areas scatter light. This local quality variation enables viewing angle control through spatial distribution rather than requiring a voltage-controlled PDLC layer.
2Illumination intensity
If the thickness of liquid crystal cell is increased to improve PDLC layer contrast, then contrast is improved, but voltage required to drive PDLC layer increases
Solution Approach 1:
The display structure is segmented into multiple functional layers including the diffuser with transparent and diffusing areas. This segmentation allows the liquid crystal cell to maintain standard thickness while achieving contrast control through the combined effect of the liquid crystal layer and diffuser pattern.
3Illumination intensity
If the optical path length through PDLC is increased to improve contrast, then contrast is improved, but risk of image blurring increases
Solution Approach 1:
The optical path is segmented by the alternating transparent and diffusing areas in the diffuser layer. This segmentation allows light to travel through a standard thickness liquid crystal cell without excessive path length, maintaining image clarity while achieving contrast through the patterned diffuser structure.
4Adaptability or versatility
If diffusing areas are made wider than transparent areas, then wide viewing angle in public mode is improved, but luminance balance is maintained
Solution Approach 1:
The diffuser structure uses asymmetric area distribution where diffusing areas are wider than transparent areas. This asymmetry optimizes the wide viewing angle performance in public mode while the specific width ratio (0.5-0.9) maintains luminance balance between the two area types.
Solution Approach 2:
The width ratio of transparent areas to pitch is controlled within a specific range (0.5-0.9) to optimize both viewing angle and luminance balance. This parameter optimization allows the diffusing areas to be wider while maintaining overall luminance balance.
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 provides a narrow viewing angle in private mode and a wide viewing angle in public mode, reducing manufacturing costs and image blurring risks while maintaining consistent luminance.
Implementation Method 1
diffusion parts formed of a transparent resin containing a plurality of diffusing particles in the diffusing areas
Implementation Method 2
forming a transparent resin layer, which contains a plurality of diffusing particles and is curable by ultraviolet rays
Data Source
AI summary
Provided are diffuser, method of manufacturing same, and liquid crystal display device employing the diffuser. Liquid crystal display device includes: backlight unit; liquid crystal panel on which image is formed by using light emitted by backlight unit, and comprising: color filter comprising plurality of pixels each of which comprises plurality of subpixels that are alternately arranged and transmit light in different wavelength bands; and liquid crystal layer whose transmittance is adjusted under electrical control; and diffuser disposed on a top surface or a bottom surface of the liquid crystal panel and comprising diffusing areas and transparent areas which alternate with each other at intervals corresponding to the width of the subpixels, wherein the liquid crystal layer comprises liquid crystal areas corresponding to the diffusing areas and liquid crystal areas corresponding to the transparent areas and the transmittances of the liquid crystal areas are adjusted according to the subpixels.