Liquid Crystal Display Device with Oxide Semiconductor Transistor
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Solution Overview
Problem
Liquid crystal display devices face challenges in maintaining display quality at low refresh rates, particularly when displaying still images, as voltage changes can lead to flickers due to exceeding acceptable gray level deviations, which degrade image quality.
Innovation Solution
A liquid crystal display device with a pixel using a liquid crystal layer having a dielectric constant anisotropy of 2 to 5, incorporating a transistor with an oxide semiconductor, to maintain voltage within acceptable gray level ranges, reducing flickers and enhancing display quality at frame frequencies of 1 Hz or lower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the refresh rate is reduced to extend operation time and reduce power consumption, then power consumption is reduced, but display quality deteriorates due to flickers caused by voltage changes exceeding acceptable gray level deviation ranges
Solution Approach 1:
The patent changes the dielectric constant anisotropy parameter of the liquid crystal layer to a specific range (2 to 5) to optimize the relationship between voltage holding and response characteristics. This parameter optimization allows the liquid crystal display to maintain stable gray levels at low refresh rates while preserving adequate response speed, thereby resolving the contradiction between power consumption reduction and display quality maintenance
Solution Approach 2:
The patent employs a transistor with an oxide semiconductor layer that exhibits dynamic electrical characteristics, enabling effective voltage holding during the inter-refresh period. The transistor's ability to maintain stable electrical properties allows the display to sustain image quality without requiring frequent refresh operations, thus reducing power consumption while preventing flicker
2Duration of action of moving object
If the frame frequency is lowered to reduce power consumption, then operation time is extended, but voltage changes cause flickers that reduce display quality
Solution Approach 1:
The patent optimizes the dielectric constant anisotropy parameter of the liquid crystal layer to a specific range (2 to 5) to balance voltage holding capability and response speed. This parameter optimization enables the display to maintain stable gray levels over extended periods between refresh operations, preventing flicker while extending operation time through reduced refresh frequency
Solution Approach 2:
The oxide semiconductor transistor provides self-service voltage holding functionality, maintaining the electrical state without external intervention during the inter-refresh period. This self-sustaining voltage holding capability allows the display to operate at extended durations between refresh cycles while maintaining display quality, thus extending operation time without sacrificing reliability
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
The solution effectively reduces flickers and maintains display quality by keeping voltage changes within acceptable ranges, even at low refresh rates, thereby improving the overall display quality and reducing eye strain.
Implementation Method 1
the liquid crystal layer has a dielectric constant anisotropy of greater than or equal to 2 and less than or equal to 5
Implementation Method 2
a liquid crystal layer having a dielectric constant anisotropy of greater than or equal to 2 and less than or equal to 5
Data Source
AI summary
A novel liquid crystal display device without a decrease in display quality. The liquid crystal display device includes a pixel for displaying a still image at a frame frequency of less than or equal to 1 Hz, and a liquid crystal layer in the pixel has a dielectric constant anisotropy of greater than or equal to 2 and less than or equal to 5. With the above structure, a change in voltage applied to a pixel can be kept within an acceptable range of a deviation in gray level for displaying the same still image. Thus, flickers due to a low refresh rate can be reduced, which leads to an increase in display quality.