Demultiplexer Circuit Timing for LCD Panel Quality
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Solution Overview
Problem
Liquid crystal display devices with touch and non-touch functions experience a difference in display quality due to varying deterioration rates of TFTs in demultiplexer circuits when driven in a time-division manner, leading to increased design and manufacturing costs when trying to match these rates.
Innovation Solution
Configuring the demultiplexer circuits on both touch and non-touch panels with identical TFTs, ensuring the high-level periods of control signals are approximately equal, allowing for synchronized deterioration and maintaining display quality over time without the need for separate masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the data lines of two liquid crystal panels (one with touch function, one without) are driven in a time-division manner, then the design flexibility and cost-effectiveness are improved, but a difference in display quality is generated between the two panels due to different deterioration rates of TFTs in the demultiplexer circuits
Solution Approach 1:
The patent applies parameter changes by adjusting the high-level period durations of control signals (RSW, GSW, BSW) to different values. Specifically, the high-level period of RSW is set longer than GSW, and GSW is set longer than BSW. This differential parameter adjustment compensates for the different deterioration rates of TFTs in panels with and without touch functions, ensuring uniform display quality over time while maintaining time-division driving benefits
2Reliability
If TFTs of different sizes are used in demultiplexer circuits of panels with and without touch functions to match deterioration rates, then display quality consistency is improved, but design cost and manufacturing cost increase
Solution Approach 1:
Instead of changing the physical size of TFTs (which would increase manufacturing complexity and cost), the patent changes the electrical parameters - specifically the high-level period durations of control signals. This allows uniform TFT sizes to be used across all panels while still achieving matched deterioration rates, thereby maintaining display quality consistency without increasing manufacturing cost
Solution Approach 2:
The patent makes the demultiplexer circuits universal by using identical TFT sizes and circuit configurations in both panels with and without touch functions. The only differentiation is in the control signal timing parameters, which allows a single design to serve multiple panel types, reducing design and manufacturing costs while ensuring consistent display quality
Data Source
AI summary
A display device includes a first display panel with a touch function, a second display panel without a touch function, a first data line drive circuit and a first demultiplexer circuit configured to drive data lines of the first display panel in a time-division manner in accordance with K first control signals, and a second data line drive circuit and a second demultiplexer circuit configured to drive data lines of the second display panel in a time-division manner in accordance with K second control signals. A horizontal period used to drive the first display panel is shorter than a horizontal period used to drive the second display panel, and a length of a period in which each of the first control signals is at a selection level and a length of a period in which each of the second control signals is at a selection level are approximately the same.