PDLC Display Interelectrode Distance Variation
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Solution Overview
Problem
Display devices using polymer dispersed liquid crystal (PDLC) with edge light methods experience decreased luminance as the distance from the light source increases, leading to a degradation in display quality.
Innovation Solution
The design includes a first substrate with a pixel electrode and a second substrate with a common electrode, separated by specific distances, and a liquid crystal layer containing polymer and liquid crystal molecules, where the interelectrode distance decreases as the distance from the light emitting element increases, enhancing the electric field strength and maintaining luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the edge light method is used in the PDLC display device, then the device can switch between transparent and scattered states, but the luminance decreases as the distance from the light source increases
Solution Approach 1:
The patent applies local quality by varying the interelectrode distance across different regions of the display device. Specifically, the distance between the common electrode and pixel electrode is made shorter in regions farther from the light emitting element and longer in regions closer to the light source. This non-uniform electrode spacing compensates for the luminance decrease by adjusting the electric field strength locally, thereby maintaining consistent display quality across the entire display area.
2Ease of manufacture
If the interelectrode distance is increased, then the manufacturing is easier with uniform spacing, but the electric field strength decreases leading to reduced luminance in distant regions
Solution Approach 1:
The patent employs asymmetry by intentionally creating non-uniform interelectrode distances. The distance between electrodes varies systematically across the display, being shorter in regions farther from the light source and longer in regions closer to it. This asymmetric configuration optimizes the electric field distribution to compensate for the inverse-square law effect, ensuring that regions receiving less light have stronger electric fields to maintain comparable luminance.
3Illumination intensity
If the interelectrode distance is decreased, then the electric field strength increases improving luminance, but the manufacturing precision requirements increase
Solution Approach 1:
The patent implements dynamics by making the interelectrode distance a variable parameter rather than a fixed value. The electrode spacing is dynamically adjusted across different spatial positions to match the luminance distribution requirements. This dynamic configuration allows the system to optimize electric field strength where needed while avoiding uniform high-precision requirements across the entire device, as the precision demands vary by location.
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 effectively suppresses the decrease in luminance and display quality by adjusting the interelectrode distance and electric field strength across the display device, ensuring consistent visibility from the incident to the anti-incident side.
Implementation Method 1
A display device that switches a transparent state and a scattered state using a polymer dispersed liquid crystal (PDLC) has been proposed. This is a technique for switching a transparent state and a scattered state by partially applying a voltage to PDLC
Implementation Method 2
a light emitting element opposed to an end surface of the second substrate... when the edge light method is used in the PDLC display device the luminance is decreased as the distance from the light source increases
Implementation Method 3
the common electrode being separated from the pixel electrode by a first distance, at a first position, the common electrode being separated from the pixel electrode by a second distance, at a second position more separated from the light emitting element than the first position, the second distance being smaller than the first distance
Data Source
AI summary
According to one embodiment, a display device includes a first substrate including a pixel electrode, a second substrate including a common electrode, a liquid crystal layer located between the first substrate and the second substrate and containing polymer and liquid crystal molecules, and a light emitting element opposed to an end surface of the second substrate, the common electrode being separated from the pixel electrode by a first distance, at a first position, the common electrode being separated from the pixel electrode by a second distance, at a second position more separated from the light emitting element than the first position, the second distance being smaller than the first distance.