Capacitive Touch Display Electrode Segmentation and Time-Multiplexing
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Solution Overview
Problem
Existing touch-sensitive displays in portable electronic devices face challenges in optimizing touch detection and noise reduction due to limited space and interference from display electrodes, which affects the accuracy and clarity of user input.
Innovation Solution
The implementation of a touch-sensitive display design that includes scanning electrodes interspersed with pixel electrodes, sense electrodes spaced from the scanning electrodes, and a display material, with a controller configured to drive the electrodes during horizontal blanking times to enhance touch sensing and reduce noise interference, allowing for improved touch detection and display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scanning electrodes are interspersed with pixel electrodes and sense electrodes are spaced from scanning electrodes, then touch detection accuracy is improved, but device complexity increases
Solution Approach 1:
The electrode system is segmented into distinct functional components: pixel electrodes for display, scanning electrodes for row selection, and sense electrodes for column sensing. This segmentation allows each electrode type to be optimized for its specific function while reducing interference between functions, thereby improving touch detection accuracy without requiring a completely new electrode architecture.
Solution Approach 2:
The patent implements a mutual capacitance touch sensing system that adds a temporal dimension to the traditional spatial electrode arrangement. By utilizing horizontal blanking periods for touch sensing operations, the system operates in time-multiplexed fashion, allowing touch detection to occur during intervals when pixel data is not being updated, thus improving touch detection capability without interfering with display refresh operations.
2Productivity
If touch sensing is performed during horizontal blanking time periods, then touch panel report frequency is enhanced, but display update time is reduced
Solution Approach 1:
The system employs periodic touch sensing operations that are synchronized with the display refresh cycle. Touch sensing is performed during horizontal blanking periods, which occur periodically between display line updates. This periodic action allows the system to maintain high touch panel report frequency while ensuring that display update operations are not interrupted, as the sensing occurs in the natural idle periods of the display refresh cycle.
Solution Approach 2:
The display system maintains continuous operation by performing touch sensing during horizontal blanking periods rather than interrupting the display update process. This approach ensures that the useful action of display refresh continues uninterrupted while touch sensing simultaneously occurs in the available time windows, maximizing both touch detection capability and display performance without sacrificing either function.
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 touch panel report frequency and signal-to-noise ratio, providing more accurate and efficient touch detection while maintaining display clarity and reducing the number of layers, thus improving the overall user experience and device performance.
Implementation Method 1
a touch-sensitive display during horizontal blanking time periods of the touch-sensitive display
Data Source
AI summary
A touch-sensitive display includes a substrate, pixel electrodes disposed on the substrate, scanning electrodes interspersed with the pixel electrodes, sense electrodes spaced from the scanning electrodes, and a display material disposed between the scanning electrodes and the sense electrodes.