Switch Circuit Portion for Display Signal Line Driver
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Solution Overview
Problem
In display devices using thin film transistors with amorphous or microcrystalline semiconductors, the size of transistors in signal line driver circuits needs to be large to ensure adequate charge and discharge of signal lines, leading to increased costs and a larger pixel portion frame.
Innovation Solution
A display device structure where a switch circuit portion controls the output of non-inverted and inverted video signals to pixel portions using distinct power supply potentials, allowing for reduced transistor size while maintaining efficient signal line charge and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transistor size in signal line driver circuits is increased to ensure adequate charge and discharge of signal lines, then the signal line performance is improved, but the frame size of the display device increases and cost rises
Solution Approach 1:
The signal line driver circuit is divided into multiple independent switch circuit portions (first switch circuit portion, second switch circuit portion, etc.), each handling specific signal lines. This segmentation allows each transistor to be optimized for its specific function rather than requiring all transistors to be uniformly large, thereby reducing the overall frame size while maintaining adequate charge and discharge performance for each signal line group.
Solution Approach 2:
Instead of requiring all transistors to have sufficient size for maximum performance in all conditions, the invention applies partial action by having different switch circuit portions activated at different times or for different signal line groups. This allows the display device to achieve adequate signal line performance through coordinated operation of multiple smaller transistors rather than requiring each transistor to be oversized.
2Reliability
If the transistor size in signal line driver circuits is increased to ensure adequate charge and discharge of signal lines, then the signal line performance is improved, but the manufacturing cost increases
Solution Approach 1:
By segmenting the signal line driver circuit into multiple switch circuit portions with smaller transistors, the invention reduces the total semiconductor material required and simplifies the manufacturing process. Smaller transistors are easier and less costly to manufacture with consistent performance characteristics, thereby reducing overall manufacturing cost while maintaining adequate signal line charge and discharge performance through the coordinated operation of multiple segments.
3Ease of operation
If multiple connection terminals are provided as many as signal lines in COG or COF structures, then video signals can be input through dedicated terminals, but the number of connection terminals increases causing cost rise
Solution Approach 1:
The switch circuit portions are designed to handle multiple signal lines through selective switching rather than requiring dedicated connection terminals for each signal line. The same physical connection structure can serve multiple functions by routing different signal lines through the switch circuit portions at different times or configurations, thereby reducing the total number of connection terminals needed while maintaining full video signal input capability.
Data Source
AI summary
A display device includes a pixel portion to which a non-inverted video signal is input in a first period and an inverted video signal is input in a second period, and a signal line driver circuit comprising a switch circuit portion for controlling output of the non-inverted video signal and the inverted video signal to the pixel portion. The switch circuit portion is controlled by a first signal serving as a first high power supply potential and a first low power supply potential in the first period and is controlled by a second signal serving as a second high power supply potential and a second low power supply potential in the second period, so that the switch circuit portion controls output of the non-inverted video signal and the inverted video signal to the pixel portion.