Touch Sensor Driver Voltage Adjustment for Display Electrode Density
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Solution Overview
Problem
Existing touch sensors on display devices face challenges in maintaining accurate touch performance and minimizing light scattering and transmittance reduction when the electrode density is changed, affecting touch sensitivity.
Innovation Solution
A display device with a touch sensor system that includes separate regions with different electrode densities and a driver mechanism to adjust the voltage level and accumulated number of touch signals, ensuring optimal touch performance by adapting to changes in electrode density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electrode density of touch sensors is increased to improve touch sensitivity, then touch sensitivity is improved, but light scattering and transmittance reduction occur
Solution Approach 1:
The touch sensor panel is divided into multiple regions with different electrode densities. The first region (sensing region) has a first electrode density optimized for touch detection, while the second region (display region) has a second electrode density optimized for light transmittance. This local differentiation allows each region to have optimal characteristics for its specific function, resolving the contradiction between touch sensitivity and light transmittance.
2Object-affected harmful factors
If the electrode density of touch sensors is changed to optimize for different regions, then optical characteristics are improved, but touch performance accuracy deteriorates
Solution Approach 1:
The touch sensor driver dynamically adjusts the driving voltage applied to touch sensors based on their electrode density. Touch sensors in the first region receive a first driving voltage, while touch sensors in the second region receive a second driving voltage. This dynamic voltage adjustment compensates for the density differences and maintains uniform touch detection accuracy across the entire panel.
Solution Approach 2:
The system changes the driving voltage parameter according to the electrode density of different regions. By adjusting the voltage parameter, the system compensates for the varying electrode densities and ensures that touch sensors across different regions produce consistent and accurate touch detection results.
3Ease of manufacture
If identical electrode density is applied uniformly across the screen, then manufacturing is simplified, but light scattering occurs and touch sensitivity varies in different regions
Solution Approach 1:
Instead of applying identical electrode density uniformly, the patent implements local quality by assigning different electrode densities to different regions. The sensing region uses higher electrode density for optimal touch detection, while the display region uses lower electrode density for optimal light transmittance, thereby eliminating light scattering issues while maintaining manufacturing feasibility through region-specific optimization.
Data Source
AI summary
A display device includes a pixel unit including a sensing region where pixels are disposed at a first pixels per inch (PPI) and a display region where pixels are disposed at a second PPI; a touch sensor unit disposed on the pixel unit, and including a first touch sensor region where touch sensors are disposed at a first electrode density and a second touch sensor region where touch sensors are disposed at a second electrode density higher than the first electrode density; a display panel driver configured to drive the pixel unit; and a touch sensor driver configured to change at least one of a voltage level of a driving pulse applied to the first touch sensor region and an accumulated number of the touch signals sensed from the first touch sensor region based on the touch signals sensed from the first touch sensor region overlapping with the sensing region.