PDLC Display Light Guide for Uniform Edge Illumination
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Solution Overview
Problem
Existing polymer dispersed liquid crystal (PDLC) display devices using an edge light type suffer from decreased luminance as the location moves away from the light sources due to inefficient light distribution.
Innovation Solution
The display device incorporates a light guide element with a transparent layer having a refractive index lower than the transparent substrate, which is bonded to the display panel substrates, optimizing light distribution and reducing luminance variations across the display area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an edge light type configuration is used in PDLC display devices, then the device structure is simplified and light sources can be positioned at the end portion of the light guide, but the luminance decreases as the location moves away from the light sources
Solution Approach 1:
The patent applies local quality by varying the thickness of the light guide in different regions. The light guide has a first thickness in a first region and a second thickness in a second region, with the second thickness being greater than the first thickness. This thickness variation is designed to compensate for the luminance decrease that occurs as light travels away from the light source, ensuring more uniform illumination across the display area while maintaining the simplified edge light type structure.
2Ease of manufacture
If light sources are positioned at the end portion of the light guide, then the device structure is simplified, but light distribution becomes inefficient and luminance decreases away from the light sources
Solution Approach 1:
The patent employs parameter changes by modifying the physical dimension (thickness) of the light guide. The light guide thickness is varied from a first thickness in the first region to a second thickness in the second region. This parameter change optimizes light distribution by allowing more light to penetrate in regions farther from the light source, thereby improving overall light distribution efficiency while preserving the ease of manufacture associated with the edge light type configuration.
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 configuration enhances light uniformity and maintains consistent luminance across the display area, reducing the impact of non-uniform illumination and improving overall display quality.
Implementation Method 1
a light guide element comprising a third transparent substrate including a main surface and a side surface opposing the plurality of light emitting elements and a transparent layer disposed on the main surface and having a refractive index lower than that of the third transparent substrate
Data Source
AI summary
According to one embodiment, a display device including a liquid crystal layer containing strip-like polymers and liquid crystal molecules, a third transparent substrate, and a transparent layer disposed on the third transparent substrate and having a refractive index lower than that of the third transparent substrate, wherein the transparent layer includes strip portions which include first and second end portions, and a middle portion, the first end portion has a first width greater than a width of the middle portion, the second end portion has a second width greater than the width of the middle portion, and first wiring lines overlap the strip portions, respectively and extend in a same direction.