PDLC Display Refractive Index Pixel Segmentation for Moiré Control
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Solution Overview
Problem
Display devices using polymer dispersed liquid crystal (PDLC) face a drawback in the edge light mode, where the brightness of the display surface decreases as the distance from the light source increases, and the introduction of a triangular-shaped transparent layer can lead to moiré creation between the transparent layer and pixels.
Innovation Solution
The display device incorporates a display panel with a first substrate and a second substrate, featuring a liquid crystal layer with polymer dispersed liquid crystals, and includes light emitting elements. The first substrate has pixel electrodes connected to switching elements, while the second substrate has a common electrode opposing the pixel electrodes. The display panel is divided into regions with varying ratios of first pixels, which include a transparent layer with a lower refractive index, and second pixels, which include an insulating layer with a higher refractive index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a triangular-shaped transparent layer is provided on the liquid crystal panel to improve light distribution, then brightness uniformity is improved, but moiré is created between the transparent layer and pixels
Solution Approach 1:
The patent divides the transparent layer into multiple regions corresponding to different pixel types (first pixels with transparent layers and second pixels with insulating layers). This segmentation eliminates the continuous triangular pattern that causes moiré while maintaining light distribution benefits in each segment.
Solution Approach 2:
The patent applies different structures to different regions: first pixels have transparent layers while second pixels have insulating layers. This local differentiation allows the system to achieve uniform light distribution without creating a uniform repeating pattern that would cause moiré across the entire display.
2Device complexity
If edge light mode is used in PDLC display devices, then device complexity is reduced, but brightness decreases as distance from light source increases
Solution Approach 1:
The patent creates different pixel types with different optical properties (first pixels with transparent layers for light guidance, second pixels with insulating layers for light blocking). This local differentiation enables the edge light mode to achieve uniform brightness distribution without requiring complex additional components.
Solution Approach 2:
The transparent layer acts as an intermediary element that guides and distributes light from the edge light source across the display panel. It mediates between the light source and the liquid crystal layer, enabling uniform illumination while maintaining the simple edge light structure.
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 helps to maintain uniform light distribution across the display area, reducing the degradation of image quality due to varying cell gaps and preventing moiré formation, thus enhancing the overall display quality.
Implementation Method 1
each of the plurality of first pixels includes a transparent layer that has a refractive index lower than those of the first base and the second base... each of the plurality of second pixels includes a first insulating layer that has a refractive index higher than that of the transparent layer
Data Source
AI summary
According to one embodiment, in a display device, the display panel includes pixels each including first pixels and second pixels, each of the first pixels has a transparent layer that has a refractive index lower than those of a first substrate and a second substrate and is in contact with a common electrode, each of the second pixels includes a first insulating layer that has a refractive index higher than that of the transparent layer and is in contact with the common electrode.