Peripheral Electrode for LCoS Display Voltage Uniformity
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Solution Overview
Problem
Liquid crystal on silicon (LCoS) display devices experience non-uniform intensity representation across their display area, especially when driven with high-frequency voltage, leading to perceived color distortions and reduced image quality.
Innovation Solution
A peripheral input electrode is introduced to efficiently distribute voltage changes across the transparent electrode, minimizing impedance variation and ensuring uniform intensity representation by extending along and being electrically coupled to the edges of the transparent electrode, which is formed from a material with lower impedance than the transparent electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a transparent electrode with long aspect ratio is used to cover the display area, then the display area can be adequately covered, but impedance variation across the electrode causes non-uniform intensity representation
Solution Approach 1:
The transparent electrode is segmented into multiple regions by introducing peripheral input electrodes that divide the electrode into distinct zones. This segmentation allows each region to be independently controlled or compensated, reducing the overall impedance variation across the entire electrode and improving intensity uniformity.
Solution Approach 2:
Peripheral input electrodes serve as intermediary elements between the voltage source and the main transparent electrode. These intermediate electrodes distribute voltage more uniformly across the display area, acting as mediators that reduce impedance variation and prevent non-uniform intensity representation.
2Speed
If high-frequency voltage is applied to the transparent electrode for fast response, then response speed is improved, but impedance variation causes non-uniform intensity and color distortions
Solution Approach 1:
Peripheral input electrodes are positioned at the edges of the display area to preemptively distribute voltage before it propagates across the entire electrode. This preliminary action ensures that voltage reaches all regions simultaneously, preventing non-uniform intensity and color distortions even during high-frequency operation.
Solution Approach 2:
The peripheral input electrodes act as intermediary voltage distribution points that mediate between the voltage source and the pixel array. They ensure uniform voltage propagation across the electrode during high-frequency switching, maintaining both fast response and intensity uniformity.
3Reliability
If the transparent electrode is made thinner to reduce impedance, then electrical performance is improved, but mechanical strength and stability are reduced
Solution Approach 1:
The electrode system is segmented into a thin transparent electrode for electrical performance and separate peripheral input electrodes for structural support. This segmentation allows the main electrode to be optimized for low impedance while the peripheral structure provides mechanical strength.
Solution Approach 2:
The electrode structure uses a composite arrangement combining a thin transparent electrode material (for low impedance) with peripheral input electrode structures (for mechanical support). This composite configuration achieves both electrical performance and mechanical strength.
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 solution allows for uniform intensity values across the display area even at high-frequency voltage driving, reducing color distortions and maintaining image quality by minimizing voltage propagation delay and impedance variation.
Implementation Method 1
A peripheral input electrode is introduced to efficiently distribute voltage changes across the transparent electrode, minimizing impedance variation
Implementation Method 2
The polarization of the light is altered by liquid crystal layer 208, depending on the electrical field applied across the liquid crystal
Data Source
AI summary
A liquid crystal display device includes a first substrate, a pixel array formed on the first substrate, a transparent substrate, a liquid crystal layer disposed between the pixel array and the transparent substrate, a transparent electrode disposed between the transparent substrate and the liquid crystal layer, and an input electrode. The transparent electrode has a longer first edge and an orthogonal shorter second edge. The input electrode extends along, and is electrically coupled along, the first edge of the transparent electrode and has lower impedance than a portion of the transparent electrode overlying the pixel array. The input electrode can include additional portion(s) that extend along, and that are electrically-coupled along, the other edges of the transparent electrode. The input electrode reduces the common voltage propagation delay across the transparent electrode and improves reduces intensity variation over the display area, even for high-frequency common voltage waveforms.