Touchscreen panel signal processing
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Solution Overview
Problem
Touchscreen panels face challenges in balancing power consumption, detection accuracy, and responsivity due to the number of sensor areas measured, with down-sampling reducing resolution and increasing noise signals, requiring higher excitation voltages for accurate touch event detection.
Innovation Solution
A method that involves obtaining a partial frame by sampling a subset of sensor areas, generating estimates for un-sampled parts, determining touch events, and acquiring sub-frames around detected events to maintain accuracy while reducing energy consumption and improving responsivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If down-sampling is used to reduce the number of sensor areas read, then power consumption is reduced and responsivity is improved, but detection accuracy and resolution are reduced
Solution Approach 1:
The patent applies preliminary action by performing a first down-sampling to obtain a partial frame, then using that partial frame to identify regions of interest before performing a second, more targeted down-sampling or sampling only those regions. This preliminary identification step allows the system to focus resources on areas where touch events are likely to occur, maintaining detection accuracy while reducing overall power consumption.
Solution Approach 2:
The patent implements partial action by reading only a subset of sensor areas rather than the complete array. The system divides the sensor array into multiple regions and selectively reads only certain regions or uses interpolation to estimate values for un-read regions, thereby reducing the number of measurements needed while maintaining sufficient detection accuracy.
2Speed
If down-sampling is used to reduce the number of sensor areas read, then responsivity is improved, but detection accuracy and resolution are reduced
Solution Approach 1:
The patent performs preliminary down-sampling to quickly obtain a partial frame and identify potential touch regions, then focuses subsequent reading efforts on those specific regions. This two-stage approach maintains high responsivity by quickly identifying areas of interest while improving detection accuracy by concentrating measurement resources on relevant regions.
Solution Approach 2:
The patent segments the sensor array into multiple regions and selectively processes or reads only certain segments based on detected touch events. By dividing the array into zones and handling them differently (full read vs. interpolated), the system achieves both fast responsivity and maintained accuracy in critical areas.
3Use of energy by moving object
If fewer sensor areas are read, then power consumption is reduced, but resolution is reduced
Solution Approach 1:
The patent reads only a partial set of sensor areas rather than the complete array, using down-sampling techniques to obtain sufficient resolution for touch detection. By reading fewer sensor areas and using interpolation or estimation for un-read regions, the system reduces power consumption while maintaining adequate resolution for practical touch event detection.
Solution Approach 2:
The system performs preliminary reading of a subset of sensor areas to identify touch regions, then uses that information to guide subsequent full-resolution reading only where needed. This preliminary action allows the system to maintain overall resolution requirements while minimizing the number of sensor areas that need to be continuously read at full resolution.
4Measurement precision
If higher excitation voltages are used to overcome noise signals, then detection accuracy is improved, but power consumption is increased
Solution Approach 1:
The patent applies excitation voltages selectively to only those sensor areas or regions where touch events are detected or suspected, rather than applying high excitation voltages to the entire array continuously. This partial application of excitation maintains detection accuracy in relevant regions while significantly reducing overall power consumption.
Solution Approach 2:
The system performs preliminary detection using lower power readings to identify regions containing touch events, then applies higher excitation voltages only to those identified regions for confirmed detection. This preliminary identification step prevents unnecessary high-power operation in regions without touch events.
Data Source
AI summary
A method for processing signals from a touchscreen panel includes obtaining a partial frame by sampling parts of a frame from a touch panel which comprises an array of sensor areas (step S1). The method also includes generating, based on the partial frame, a new frame which comprises estimates of the un-sampled parts (step S2). The method also includes determining whether at least one touch event is present in the new frame (step S3), and upon a positive determination, for each touch event, determining a location of the touch event in the new frame and obtaining a sub-frame by sampling a region of a subsequent frame from the touch panel frame at and around the location (step S4). The method also includes outputting touch information based on one or more sub-frames (step S7).