Touch Path Logic for Display Lag Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Touch input devices, such as mobile phones and tablets, experience significant display lag due to high latency between touch sensor panels and display devices, leading to user frustration as the system takes 50 to 200 milliseconds to update the display in response to touch actions, which is noticeable to most users.
Innovation Solution
The implementation of an overlay system that includes touch path logic, rendering logic, and an overlay buffer to combine video images with overlay data based on touch events, allowing for immediate visual feedback by processing touch events independently of the application processor, reducing display lag to 1 to 2 frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If touch events are processed by the application processor through high level application software, then the system can handle complex touch interactions, but the processing latency increases to 50 to 200 milliseconds causing noticeable display lag
Solution Approach 1:
The patent segments the touch processing system into two independent paths: a low-latency path that processes touch events directly from the touch sensor panel to the display panel bypassing the application processor, and a normal path that processes touch events through the application processor for complex interactions. This segmentation allows the system to maintain versatility while reducing latency for basic touch feedback.
Solution Approach 2:
The patent introduces an intermediary component (touch path logic) that sits between the touch sensor panel and display panel, enabling direct processing of touch events without going through the application processor. This intermediary handles the time-critical task of converting touch coordinates to display coordinates and generating overlay data, thereby reducing latency while maintaining system versatility.
2Reliability
If multiple processing steps are introduced between the touch sensor panel and application processor, then the system can perform comprehensive touch event handling, but the non-deterministic processing time increases latency
Solution Approach 1:
The patent performs preliminary action by pre-calculating display coordinates from touch coordinates using a transformation matrix in the touch path logic, before the touch event reaches the application processor. This preliminary processing of coordinate transformation eliminates the need for repeated calculations in the application processor, reducing non-deterministic processing time while maintaining reliable touch event handling.
Solution Approach 2:
The patent creates a copy of the essential touch processing functionality in the touch path logic, which mirrors the coordinate transformation and overlay generation functions that would otherwise occur in the application processor. This copying allows parallel processing paths, reducing latency while maintaining the reliability of comprehensive touch event handling through the original application processor path.
3Measurement precision
If the system waits for the application processor to complete computational tasks before updating the display, then processing accuracy is maintained, but display responsiveness decreases
Solution Approach 1:
The patent segments the processing pipeline to separate accuracy-critical functions from speed-critical functions. The touch path logic handles speed-critical coordinate transformation using pre-computed transformation matrices, while the application processor maintains accuracy-critical touch event interpretation and application-level processing. This segmentation enables fast display updates without sacrificing touch coordinate accuracy.
Solution Approach 2:
The patent performs preliminary calculation of the transformation matrix that maps touch coordinates to display coordinates. This pre-computed matrix is stored and reused by the touch path logic to rapidly convert touch events to display coordinates without requiring real-time complex calculations, thereby maintaining measurement precision while achieving high display update speed.
Data Source
AI summary
An apparatus includes an overlay buffer configured to store overlay data; a touch path logic to: receive first touch events from the first touch sensor panel and generate a first output based on the first touch events, and receive second touch events from the second touch sensor panel and generate a second output based on the second touch events; and a rendering logic to, when the first touch events occur: receive a first video image; receive the first output; and combine the first video image with the overlay data corresponding to the first video image to output at least one combined display image, and, when the second touch events occur: receive a second video image; receive the second output; and combine the second video image with the overlay data corresponding to the second video image to output the at least one combined display image.