Vector Fill Segment Method Reduces Touch Display Latency
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Solution Overview
Problem
Current touchscreen devices experience high latency due to independent operation of touch and display systems, leading to noticeable delays in responding to user inputs, with contemporary smartphones exhibiting delays of about 100 milliseconds when writing on the screen.
Innovation Solution
A method and system for generating a mask overlay on a display panel corresponding to a touch path, which includes receiving touch path data, generating vertex points, determining start and stop edges of polygons, and creating a list of bin offset values to generate an accumulator value for each pixel, allowing for faster touch response by overlaying an image in advance of the application processor's rendered image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If touch events are processed by high level application software on the application processor, then the touch system can be implemented with standard processing components, but the display latency increases to about 100 milliseconds
Solution Approach 1:
The patent segments the touch processing pipeline into two independent paths: a low-latency path that processes touch events directly through the display driver interface controller (DDIC) and a standard path that processes through the application processor. This segmentation allows critical touch feedback to bypass the application processor and be rendered immediately, reducing display latency from 100 milliseconds to approximately 16.67 milliseconds (one frame period at 60Hz), while maintaining the ability to use standard processing components for non-critical operations.
Solution Approach 2:
The patent implements preliminary action by pre-processing touch events at the touch controller and preparing them for immediate rendering through the DDIC before the application processor completes its full processing cycle. The touch controller generates touch path data that is directly fed to the DDIC, which then renders the touch feedback in advance of the main application processing, ensuring that the display responds to touch inputs without waiting for the application processor to finish its computational tasks.
2Device complexity
If the application processor processes all touch events sequentially, then processing logic can be simplified, but the responsiveness to user inputs decreases
Solution Approach 1:
The patent segments the processing logic into two distinct pathways: a simplified fast path through the DDIC for immediate touch feedback, and a complete path through the application processor for full application processing. The DDIC path handles only the essential rendering of touch events with minimal processing logic, while the application processor handles complex application-specific processing. This segmentation maintains simplified logic in the critical path while preserving full functionality in the complete path, thereby improving responsiveness without sacrificing processing capability.
Solution Approach 2:
The patent introduces the display driver interface controller (DDIC) as an intermediary between the touch controller and the display panel. The DDIC acts as a mediator that receives touch path data from the touch controller and directly generates display output without requiring application processor intervention. This intermediary enables the system to maintain simplified processing logic in the fast path while achieving high responsiveness, as the DDIC handles the time-critical rendering operations independently of the application processor's processing schedule.
3Adaptability or versatility
If multiple processing operations are performed between the touch sensor panel and the application processor, then comprehensive processing can be achieved, but latency increases due to non-deterministic processing time
Solution Approach 1:
The patent segments the processing operations into two categories: deterministic operations performed by the touch controller and DDIC that guarantee fixed latency, and non-deterministic operations performed by the application processor that provide comprehensive processing capability. By segmenting the processing pipeline this way, the system achieves both comprehensive processing capability (through the application processor path) and deterministic low latency (through the touch controller to DDIC path), as the critical rendering operations are isolated from the variable processing times of application-level operations.
Solution Approach 2:
The patent implements preliminary action by performing essential touch event processing and rendering preparation in advance at the touch controller and DDIC, before the application processor completes its comprehensive processing. The touch controller pre-processes raw touch sensor data into touch path data, and the DDIC pre-prepares the display output based on this data. This preliminary action ensures that the time-critical rendering path is not blocked by the application processor's comprehensive but time-consuming processing operations, thereby reducing latency while maintaining comprehensive processing capability.
Data Source
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AI summary
A method of generating a mask overlay for a display corresponding to a touch path, the method including receiving touch path data including touch points corresponding to the touch path, generating vertex points of a vertex array corresponding to the touch points, generating a polygon for a set of the vertex points to define edges of the touch path, determining start and stop edges of the polygon for a row of pixels, generating a list of bin offset values corresponding to the row and including bin offsets for indicating the edges by incrementing a bin offset for each of the start edges, and by decrementing a subsequent bin offset for each of the stop edges, generating an accumulator value corresponding to each of the pixels, determining whether the accumulator values are greater than or equal to zero, and generating the mask overlay by determining whether respective accumulator values is greater than zero.