Liquid Crystal Display Storage Capacitance via Slit Common Electrodes
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Solution Overview
Problem
In active-matrix-type liquid crystal display devices, the storage capacitance required for maintaining voltage in the liquid crystal layer is typically formed by light-shielding materials, which reduces the aperture ratio, transmittance, and luminance per pixel, necessitating an improvement in display quality while maintaining necessary capacitance.
Innovation Solution
The liquid crystal display device incorporates a first common electrode with slits and a second common electrode opposed to the slits, allowing for the formation of a storage capacitance without the need for light-shielding wiring lines, thereby enhancing the aperture ratio and transmittance by creating an inclined electric field that contributes to improved display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light-shielding wiring lines are used to form storage capacitance, then the necessary capacitance for maintaining voltage is secured, but the aperture ratio, transmittance, and luminance per pixel decrease
Solution Approach 1:
The invention extracts the light-shielding wiring lines from the pixel structure by forming storage capacitance between the first common electrode and second common electrode. This removes the harmful light-shielding elements while preserving the necessary capacitance function for voltage maintenance.
Solution Approach 2:
The storage capacitance is formed in a different spatial dimension - between the first common electrode and second common electrode separated by insulation films, rather than using wiring lines within the pixel plane. This dimensional repositioning eliminates the conflict between capacitance formation and light transmission.
2Reliability
If light-shielding materials are used for storage capacitance, then voltage maintenance capability is improved, but the aperture ratio decreases
Solution Approach 1:
The light-shielding materials are extracted from the pixel structure by relocating the storage capacitance formation to the region between first common electrode and second common electrode, eliminating the need for light-shielding materials within the pixel aperture area.
Solution Approach 2:
Insulation films serve as intermediaries between the first common electrode and second common electrode, enabling capacitance formation without requiring light-shielding materials. The insulation films provide the necessary electrical isolation while allowing light transmission.
3Quantity of substance
If traditional storage capacitance structure is used, then capacitance is secured, but display quality deteriorates due to reduced transmittance
Solution Approach 1:
The traditional light-shielding storage capacitance structure is extracted and replaced by a new configuration using first and second common electrodes with insulation films, preserving capacitance while eliminating the negative impact on display quality.
Solution Approach 2:
The invention changes the physical parameters of the capacitance structure - using transparent insulation films with specific dielectric constants and thicknesses to achieve the necessary capacitance values without light-shielding, thereby maintaining both capacitance and display quality.
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 increases the transmittance per pixel by 1.25 times compared to traditional designs, improving display quality while securing the necessary capacitance for image display without the need for light-shielding wiring lines.
Implementation Method 1
liquid crystal molecules with a negative dielectric constant anisotropy are aligned substantially vertical to a substrate
Implementation Method 2
directions of inclination of liquid crystal molecules in one pixel are divided between a plurality of regions
Implementation Method 3
a storage capacitance is necessary for holding for a predetermined period a voltage which is applied to a liquid crystal layer
Data Source
AI summary
According to one embodiment, a liquid crystal display device includes a first substrate including a first common electrode in which a first slit extending in a first direction is formed, a first pixel electrode opposed to the first common electrode, and a second pixel electrode opposed to the first common electrode and neighboring the first pixel electrode in a second direction with the first slit being interposed, a second substrate including a second common electrode opposed to the first slit, the first pixel electrode and the second pixel electrode, and a liquid crystal layer held between the first alignment film and the second alignment film.