Variable Common Electrode Areas for Unified LCD Driving
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Solution Overview
Problem
The manufacturing costs of liquid crystal display devices are increased due to the need for separate driving circuits for subpixels emitting red, green, and white light, while blue light emission is insufficient, leading to inaccurate display and deteriorated image quality.
Innovation Solution
A liquid crystal display device design where first and second common electrodes with different areas are used to achieve similar voltage-transmittance curves for all subpixels, allowing them to be driven by the same circuit, thereby eliminating the need for separate driving circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate driving circuits are used for subpixels emitting different colors (red, green, white), then each subpixel can achieve optimal light transmittance control, but manufacturing costs increase
Solution Approach 1:
The patent applies local quality by making the common electrode area variable according to the specific color of each subpixel. Red subpixels are assigned larger common electrode areas while green and blue subpixels have smaller areas, allowing each color to achieve optimal voltage-transmittance characteristics with a unified driving circuit, thus resolving the contradiction between reliable control and manufacturing cost.
2Ease of manufacture
If a unified driving circuit is used for all subpixels, then manufacturing costs are reduced, but blue light emission becomes insufficient leading to inaccurate display
Solution Approach 1:
The patent implements local quality by differentiating common electrode areas based on subpixel color requirements. Blue subpixels, which previously suffered from insufficient emission, are assigned smaller common electrode areas to achieve proper voltage-transmittance curves, while red subpixels receive larger areas. This enables accurate display across all colors using a single unified driving circuit.
3Reliability
If different voltage-transmittance curves are used for different color subpixels, then each color can be optimized independently, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the physical dimension (area) of the common electrode rather than creating separate driving circuits. By varying the common electrode area parameter according to subpixel color, the patent achieves independent optimization of voltage-transmittance curves for each color while maintaining a unified driving circuit, thus reducing device complexity.
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 design ensures that all subpixels have similar voltage-transmittance characteristics, reducing manufacturing costs and improving image quality by ensuring adequate blue light emission.
Implementation Method 1
an electric field formed in the liquid crystal layer between pixel electrodes and common electrodes
Implementation Method 2
a liquid crystal panel including a lower substrate, an upper substrate and a liquid crystal layer filled between the lower substrate and the upper substrate
Implementation Method 3
color filter layers each of which transmits a light of a wavelength region corresponding to any one of a plurality of colors including red (R), green (G) and blue (B)
Data Source
AI summary
A liquid crystal display device capable of reducing manufacturing costs is disclosed. The liquid crystal display device includes first and second substrates facing each other, a liquid crystal layer filled between the first and second substrates, a first common electrode formed in a first pixel region on the first substrate in correspondence with a first subpixel for emitting a light of a first color, and having a first area, wherein a common voltage is applied to the first common electrode, and a second common electrode formed in a second pixel region on the first substrate in correspondence with a second subpixel for emitting light of a second color different from the first color and having a second area different from the first area, wherein the common voltage is applied to the second common electrode.