Touch Sensing System with Full Pre Local Sensing
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Solution Overview
Problem
Existing touch sensing systems face issues with coordinate loss when touch input moves rapidly across the touchscreen, leading to intermittent breakage of the touch input line, and they struggle to allocate sufficient time for sensing brightness and current control due to fixed emission duty cycles.
Innovation Solution
A touch sensing system that includes a display panel with embedded touch sensors, a display driving circuit, and a touch sensor controller that performs full sensing, pre-sensing, and local sensing to accurately detect and calculate touch input coordinates by predicting the movement of the touch input and allocating minimal pulses for pre-sensing, thereby preventing coordinate loss and optimizing sensing periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full sensing is performed across the entire touchscreen to detect touch input, then touch sensing coverage is improved, but coordinate loss occurs when touch input moves rapidly between multiplexer areas
Solution Approach 1:
The touchscreen sensing area is divided into multiple multiplexer (MUX) regions, with each MUX responsible for a specific area. This segmentation allows the system to focus sensing resources on relevant regions, improving both coverage and reliability by preventing coordinate loss when touch input moves rapidly between regions.
Solution Approach 2:
The system performs full sensing first to detect which MUX area contains touch input, then performs local sensing only on that specific MUX area. This preliminary action identifies the relevant region before detailed sensing, ensuring no coordinate loss occurs while optimizing resource allocation.
2Productivity
If local sensing is performed only on the sensing area of a specific MUX, then sensing speed is improved, but coordinate loss occurs when touch input is in a different MUX area
Solution Approach 1:
Full sensing is performed as a preliminary step to identify which MUX area contains touch input. Based on this identification, local sensing is then performed only on the relevant MUX area, ensuring both high sensing speed and accurate coordinate detection without loss.
Solution Approach 2:
The system uses feedback from full sensing results to dynamically adjust the scope of local sensing. The touch sensor controller determines which MUX area has touch input and directs local sensing resources accordingly, ensuring reliability while maintaining productivity.
3Measurement precision
If more time is allocated for touch sensing periods, then touch sensing accuracy is improved, but display period time is reduced
Solution Approach 1:
The sensing period is segmented into full sensing and local sensing phases. Full sensing uses minimal time to identify the active MUX area, while local sensing allocates more time for accurate coordinate detection only in the relevant region. This segmentation improves touch sensing accuracy without excessively reducing display period duration.
Solution Approach 2:
The system applies different sensing strategies to different MUX areas based on local conditions. When touch input is detected in a specific MUX area, more time and resources are allocated to local sensing in that region, improving accuracy where needed while preserving overall display timing.
4Device complexity
If fixed emission duty cycle is used for display driving, then display timing is simplified, but insufficient time is available for sensing brightness and current control
Solution Approach 1:
The system transitions from a fixed emission duty cycle to a dynamic timing scheme where blanking intervals are optimized based on sensing requirements. During vertical and horizontal blanking periods, the system allocates time for brightness sensing and current control while maintaining simplified display timing through structured interval division.
Solution Approach 2:
The system performs multiple functions continuously during blanking intervals without interrupting the display refresh cycle. Brightness sensing, current control, and touch sensing operations are overlapped and executed in sequence during available time slots, eliminating time loss while maintaining timing simplicity.
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
The system effectively prevents coordinate loss during fast touch input movements and enhances touch sensing accuracy, allowing for better picture quality and efficient resource utilization by optimizing the allocation of sensing periods.
Implementation Method 1
The touchscreen 100 can sense touch when a conductive object such as a finger or the active stylus pen 200 comes into contact with it, and may have an integrated capacitive touch sensor.
Data Source
AI summary
The present disclosure provides A touch sensing system comprising: a display panel having pixels and touch sensors; a display driving circuit that writes data to the pixels; a touch sensing part that senses touch input; a plurality of multiplexers that connect one of sensor lines connected to the touch sensing part; and a touch sensor controller that performs full sensing to detect a multiplexer with a sensed touch input by supplying a driving signal to the touch sensors within the touch sensing periods, performs pre-sensing to determine whether or not a touch input is sensed in multiplexers adjacent to the multiplexer with a sensed touch input, and performs local sensing to scan the touch sensors connected to the multiplexer with a sensed touch input based on the pre-sensing result and to calculate the coordinates of the touch input.