LCD Gate Voltage Generator Temperature Compensation
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Solution Overview
Problem
Conventional liquid crystal displays (LCDs) face challenges in manufacturing cost reduction and display quality improvement due to the temperature-dependent driving capability of amorphous silicon thin-film transistors (a-Si TFTs), which affect the generation of gate signals and result in insufficient voltage levels for pixel switching.
Innovation Solution
Incorporating a temperature compensation unit with a constant voltage output device and a temperature-sensing device in the gate-off voltage generator, which outputs a gate-off voltage that varies based on ambient temperature, and using a clock generator to adjust clock signals based on gate-on and gate-off voltages, ensuring stable voltage differences regardless of temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a-Si TFTs are used to generate gate signals, then manufacturing cost is reduced, but driving capability deteriorates at low temperatures
Solution Approach 1:
The patent changes the voltage parameters of gate signals based on temperature. Specifically, it adjusts the gate-on voltage and gate-off voltage levels according to temperature conditions to compensate for the deteriorating driving capability of a-Si TFTs at low temperatures, while maintaining the cost-effective a-Si TFT technology.
Solution Approach 2:
The patent implements a feedback mechanism that monitors temperature conditions and automatically adjusts gate signal voltage levels accordingly. This feedback system ensures that the gate driver maintains adequate driving capability across different temperature ranges while continuing to use cost-effective a-Si TFT technology.
2Reliability
If gate signal voltage levels are increased to improve pixel switching, then driving capability is improved, but power consumption increases
Solution Approach 1:
The patent dynamically adjusts gate signal voltage levels based on temperature conditions rather than using fixed high voltage levels. At higher temperatures where a-Si TFTs perform better, lower voltage levels are sufficient, reducing power consumption. At lower temperatures, voltage levels are increased only to the extent necessary to maintain adequate driving capability.
Data Source
AI summary
A liquid crystal display (LCD) includes: a gate-off voltage generator including a temperature compensation unit which comprises a constant voltage output device and which outputs a gate-off voltage having a level which varies based on a change in ambient temperature;a clock generator outputting a first clock signal and a second clock signal;a gate driver outputting gate signals; anda plurality of pixels which turn on or off based on the gate signals,wherein the constant voltage output device outputs a temperature variable voltage having a value based on a voltage difference between a reference terminal of the constant voltage output device and an input terminal of the constant voltage output device, and a voltage difference between the reference terminal and the input terminal of the constant voltage output device varies based on the change in the ambient temperature.