Touch Screen and Trackpad Signal Processing for Latency Reduction
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Solution Overview
Problem
Computing devices with touch screens and trackpads face challenges in balancing fast touch detection, noise immunity, and power efficiency due to latencies introduced by processing inputs at an abstraction layer.
Innovation Solution
The solution involves processing touch input signals from both the touch screen and trackpad at a physical layer, modifying detection algorithms to enhance noise immunity and reduce latency, and adjusting sensitivity and frequency ranges to minimize power consumption and noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If touch input signals are processed at an abstraction layer, then noise immunity is improved, but touch detection latency increases and response speed decreases
Solution Approach 1:
The processing system is segmented into two distinct layers: a physical layer for fast raw signal processing and an abstraction layer for noise-filtered processing. This segmentation allows each layer to perform its specialized function without compromising the other, achieving both speed and reliability.
Solution Approach 2:
An intermediary mechanism is introduced that allows the physical layer to process signals quickly while the abstraction layer provides noise immunity. The intermediary enables coordination between the two layers, allowing fast response while maintaining accuracy through cross-layer communication.
2Speed
If touch detection sensitivity is increased to reduce latency, then touch response speed improves, but false detections from noise increase
Solution Approach 1:
The system applies partial action by processing signals at different levels of sensitivity in different layers. The physical layer uses high sensitivity for speed, while the abstraction layer applies additional filtering to eliminate false detections, achieving a balanced approach that avoids excessive action in one layer.
Solution Approach 2:
The abstraction layer provides beforehand cushioning by pre-filtering signals before they reach the application layer. This cushioning effect prevents false detections from propagating upward, allowing the physical layer to operate at high sensitivity without compromising reliability.
3Speed
If touch detection frequency is increased to improve response time, then touch detection speed improves, but power consumption increases
Solution Approach 1:
The system implements periodic action by sampling touch signals at different frequencies in different layers. The physical layer uses high-frequency sampling for immediate response, while the abstraction layer uses lower-frequency sampling after initial filtering, reducing overall power consumption while maintaining speed.
Solution Approach 2:
The abstraction layer performs preliminary action by pre-processing and filtering signals before final detection. This preliminary action reduces the burden on the physical layer, allowing it to operate at high frequency for short durations without持续 high power consumption.
4Loss of time
If processing is done at physical layer for speed, then touch detection latency decreases, but noise immunity deteriorates
Solution Approach 1:
The system merges the strengths of both physical layer processing (speed) and abstraction layer processing (noise immunity) by combining their outputs. The final touch detection result integrates information from both layers, achieving both low latency and high reliability simultaneously.
Solution Approach 2:
The processing system is designed with multi-functionality, where the physical layer handles fast raw signal processing and the abstraction layer handles noise filtering and validation. Both layers serve universal purposes in the overall touch detection system, allowing the system to achieve multiple objectives simultaneously.
Data Source
AI summary
Computing devices and methods for performing touch detection on a touch screen display and trackpad are disclosed. In one example, a trackpad input signal from a trackpad is received at a processor of the device. Using at least the trackpad input signal, a touch screen touch detection algorithm is modified. A touch screen input signal is then received at the processor from the touch screen display. The touch screen input signal is processed with the modified touch screen touch detection algorithm.