Touch Sensor Invalidating Continuous Contact
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Solution Overview
Problem
Touch sensor devices face challenges in achieving high detection accuracy and resolution while enabling high-speed operation, and they often result in incorrect operations due to unintended contacts, which decrease user convenience, especially in portable devices with narrow touch panel frames.
Innovation Solution
A touch sensor system that includes a drive section for driving capacitance columns using orthogonal code sequences, an estimation section for calculating capacitance values, and a touch invalidating section that prevents instructions for continuous touches, allowing the system to differentiate between intended and unintended contacts without changing the reference values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a touch panel system is used in portable electronic devices, then the device can detect user input, but unintended contacts from holding the device cause incorrect operations
Solution Approach 1:
The system performs preliminary detection of touch duration before executing the touch operation. By measuring whether the touch continues for a predetermined period of time, the system distinguishes between intentional touches and accidental contacts from holding the device, preventing incorrect operations while maintaining normal usability
2Area of stationary object
If the frame width is reduced to increase display area, then the display-to-body ratio improves, but unintended contacts more frequently cause incorrect operations
Solution Approach 1:
The touch invalidating section performs preliminary detection of touch duration characteristics before executing operations. By measuring whether the touch continues for a predetermined period, the system identifies accidental contacts that occur more frequently in devices with narrow frames, preventing incorrect operations without reducing the display area
3Reliability
If continuous touch detection is implemented to prevent incorrect operations, then false triggers are reduced, but the system complexity increases
Solution Approach 1:
The touch invalidating section implements a simple preliminary detection mechanism that measures touch duration against a predetermined threshold. This approach improves reliability by filtering false triggers from accidental contacts while maintaining relatively low system complexity through straightforward temporal measurement and comparison logic
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 incorrect operations caused by unintended contacts while maintaining high detection accuracy and sensitivity, ensuring user convenience by distinguishing between intended and unintended touches without altering the reference values.
Implementation Method 1
a capacitance matrix Cij (i=1, . . . , M and j−1, . . . , L) formed between M drive lines and L sense lines
Implementation Method 2
an estimation section for estimating (a) on a basis of a first inner product operation of the outputs sFirst and the code sequences di, a first capacitance value in the first capacitance column
Data Source
AI summary
A touch panel system (611) includes a touch invalidating section (609) which, in a case where a specific point of the sensor panel (601) is continuously touched for a predetermined period of time, invalidates an instruction given, in accordance with the touch, to a host computer (610). Furthermore, the touch invalidating section (609) invalidates an instruction corresponding to a next touch on the point.