Touch Panel Scanning Method for Reducing Signal Processing Latency
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Solution Overview
Problem
Current touch panels face challenges in achieving acceptable response times as the size of the touch panel increases, leading to undesirable delays in detecting user inputs due to the need to scan and process signals from a large number of sensors, which is unsuitable for larger devices like tablets and televisions.
Innovation Solution
A method where multiple drive lines are simultaneously activated with the same electrical characteristics, allowing for the simultaneous application of drive signals and sensing of sense signals across the touch panel, reducing the overall scan time by applying a higher number of pulses during initial and final time slots and fewer pulses during intermediate slots, and processing the raw sense data to detect touches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the touch panel size is increased to provide larger display area, then the display area is improved, but the scan time increases leading to slower response time
Solution Approach 1:
The patent divides the drive lines into multiple groups that can be activated simultaneously. Instead of scanning drive lines sequentially one by one, the system segments the drive lines into groups and activates multiple groups at the same time, thereby reducing the total scan time while maintaining coverage of the entire large touch panel area.
Solution Approach 2:
The patent introduces a time slot dimension to organize the simultaneous activation of multiple drive line groups. By assigning different time slots to different groups of drive lines, the system enables parallel scanning across multiple dimensions (spatial groups + temporal slots), effectively reducing the overall scan time for large panels.
2Area of stationary object
If the number of drive lines and sense lines is increased to cover larger panel size, then the sensor array coverage is improved, but the number of processing steps increases
Solution Approach 1:
The patent merges multiple drive lines into groups that are activated simultaneously. Instead of processing drive lines individually through separate scanning cycles, the system combines multiple drive lines into parallel groups, reducing the number of sequential processing steps while maintaining the ability to detect touches across the entire large panel.
Solution Approach 2:
The patent creates a universal scanning mechanism that can handle multiple drive line groups simultaneously through the same basic sensing circuitry. The sense lines and processing circuitry are designed to work universally across all drive line groups, eliminating the need for separate processing paths for each drive line and thereby reducing overall processing complexity.
3Measurement precision
If sequential scanning of drive lines is used to ensure complete sensor coverage, then the measurement completeness is improved, but the response time increases
Solution Approach 1:
The patent segments the sequential scanning process into parallel group activations. By dividing the drive lines into multiple groups that can be activated simultaneously, the system maintains complete sensor coverage while reducing the time required to scan all sensors. Each group is scanned in parallel rather than sequentially, preserving measurement completeness while improving speed.
Solution Approach 2:
The patent uses periodic time slots to organize the simultaneous activation of different drive line groups. Within each time slot, multiple drive line groups are activated periodically and simultaneously, allowing the sensing circuitry to capture signals from all groups in parallel. This periodic grouping maintains complete coverage while significantly reducing the total scanning time compared to sequential scanning.
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 approach significantly reduces the scan time by 37.5% compared to conventional methods, improving the responsiveness of larger touch panels by optimizing the number of pulses and processing steps, thereby enhancing user experience.
Implementation Method 1
the capacitive coupling between that drive line and the sense lines through the corresponding sensor nodes results in capacitive coupling of the drive signal to the sense lines to thereby generate sense signals on the sense lines responsive to the drive signal
Implementation Method 2
with these layers being separated by a transparent insulating material such as glass
Data Source
AI summary
A touch panel includes a plurality of drive lines, a plurality of orthogonal sense lines, and a plurality of sensors. A method of controlling the touch panel to detect touches includes simultaneously applying a drive signal to each of a group of drive lines of the touch panel. Each of the drive signals is applied to a corresponding drive line in the group during a time slot and all the applied drive signals having the same electrical characteristics over the time slot. The method includes sensing sense signals generated on the sense lines in response to the applied drive signals and processing the sense signals to detect touches of the touch panel.