Touch Panel Aperture Ratio and Readout Accuracy via Shared Signal Lines
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Solution Overview
Problem
Conventional photo sensitive touch panels have a low aperture ratio and are prone to readout errors due to the presence of multiple signal readout lines that interfere with data lines, and require separate color filters for each RGB light source, complicating the sensing mechanism.
Innovation Solution
The touch panel design includes a configuration where each pixel comprises sub-pixels with separate photo sensitive and display areas, using a single signal readout line per column and color filters that differ in color between photo sensors and display areas, reducing the number of signal readout lines and preventing interference between pixel electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple signal readout lines are used to connect photo sensors, then all photo sensors can be connected, but the aperture ratio is reduced and readout errors increase due to interference with data lines
Solution Approach 1:
Multiple signal readout lines are merged into a single shared readout line that serves multiple photo sensors. The readout controller selectively activates specific readout lines based on which photo sensor needs to read out, eliminating the need for separate dedicated readout lines for each sensor while maintaining reliable signal transmission without interference.
2Measurement precision
If separate color filter films are used for each RGB light source, then accurate color sensing is achieved, but the device complexity increases
Solution Approach 1:
A single color filter film is designed to handle multiple color sensing functions. The filter film can selectively sense different colors (RGB) by being positioned over different photo sensors, and the same filter structure serves multiple sub-pixels within a pixel unit, reducing overall device complexity while maintaining color sensing accuracy.
Solution Approach 2:
Different regions of the color filter film have different optical properties tailored to specific sensing needs. The filter film is configured with different color filtering characteristics at different locations to match the specific color sensing requirements of underlying photo sensors, achieving accurate color differentiation without requiring entirely separate filter structures for each color.
3Ease of manufacture
If pixel electrodes are shared between photo sensitive area and display area, then manufacturing is simplified, but interference between areas occurs causing readout errors
Solution Approach 1:
The pixel electrode is divided into separate, isolated electrode structures for the photo sensitive area and the display area. This segmentation prevents electrical interference and signal leakage between the two functional areas, ensuring accurate signal readout from photo sensors while maintaining the ability to drive display elements independently.
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 enhances the aperture ratio and reduces readout errors while allowing for efficient sensing of multiple light colors, improving the overall performance of the touch panel.
Implementation Method 1
After the touch panel is illuminated, an amorphous silicon semiconductor layer of the sensor TFT produces a leakage current, a current value of the sensor TFT is read out through the readout TFT and then a voltage value is obtained. The voltage value can represent the strength of light illuminating to the touch panel.
Data Source
AI summary
A touch panel is provided. The touch panel includes a plurality of pixels, wherein each pixel includes M*N sub-pixels, at least m sub-pixels each include at least one photo sensitive area and at least one effective display area, the other n sub-pixels each include only at least one effective display area, M≧2, N≧1, m≦M, m+n=M and m≧0. A first color filter film is disposed over a photo sensor of the photo sensitive area and a second color filter film is disposed over the effective display area, wherein the color of the first and second color filter films are the same at the same sub-pixel. The photo sensors at the same column of the sub-pixels are electrically connected by a signal readout line, wherein only one signal readout line is disposed at every M column of the sub-pixels.