Capacitive Touch Sensing Segmentation for Precision and Speed
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Solution Overview
Problem
Conventional touch panel systems face challenges in reducing sensing time and power consumption while preventing errors during the finger approach sensing process, which is performed as a standby mode before the finger coordinate sensing process.
Innovation Solution
A display device and input device design that includes a sensing unit which collectively senses the electrostatic capacitance of all or part of the sensing electrodes in a matrix pattern to detect object approaches or contacts, and individually senses each electrode to determine the position when a contact is detected, allowing for repeated sensing if no contact is initially sensed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrostatic capacitance of each sensing electrode is sensed by sequentially switching and connecting the plurality of sensing electrodes one by one or in units of several sensing electrodes to a sensing circuit, then measurement precision is improved, but time required for the sensing process increases and power consumption increases
Solution Approach 1:
The sensing process is divided into two distinct phases: a first sensing process that collectively senses electrostatic capacitance of multiple sensing electrodes to detect object approach, and a second sensing process that individually senses each electrode only when approach is detected. This segmentation allows the system to maintain measurement precision while reducing overall sensing time and power consumption.
Solution Approach 2:
The system implements periodic sensing cycles that alternate between the collective first sensing process and the individual second sensing process based on detection needs. This periodic action pattern ensures that detailed individual sensing is performed only when necessary, optimizing the balance between precision and efficiency.
2Measurement precision
If electrostatic capacitance of each sensing electrode is sensed by sequentially switching and connecting the plurality of sensing electrodes one by one or in units of several sensing electrodes to a sensing circuit, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The sensing operation is segmented into low-power collective sensing and high-precision individual sensing phases. By performing collective sensing of multiple electrodes simultaneously in the first process, the system reduces the frequency and duration of high-power individual sensing operations, thereby lowering overall power consumption while maintaining precision when needed.
Solution Approach 2:
The system performs partial individual sensing only on electrodes where object approach has been detected, rather than continuously sensing all electrodes individually. This partial action approach maintains measurement precision for relevant areas while avoiding unnecessary power consumption in areas without objects.
3Productivity
If several sensing electrodes are selected from part of the plurality of sensing electrodes or a waiting time between the sensing processes to be repeated is increased in order to shorten the time required for the sensing process, then productivity is improved, but sensing error occurs
Solution Approach 1:
The sensing system is segmented into a broad-coverage first sensing process that monitors all electrodes collectively for object approach, and a focused second sensing process that individually examines only electrodes where approach is detected. This segmentation enables rapid detection without sacrificing accuracy, as the collective process ensures no area is missed while the individual process provides precise positioning.
Solution Approach 2:
The system uses feedback from the first collective sensing process to control when and where the second individual sensing process is activated. When object approach is detected in a specific region, the feedback triggers detailed individual sensing only in that region, ensuring sensing accuracy is maintained while improving overall productivity by avoiding unnecessary sensing in areas without objects.
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
This approach reduces the time required for the sensing process and minimizes power consumption while preventing sensing errors by utilizing all electrode groups for detection and ensuring accurate finger position determination.
Implementation Method 1
a sensing unit which senses electrostatic capacitance of each of the plurality of first electrodes
Implementation Method 2
the input positions are sensed by utilizing the characteristics that the electrostatic capacitance of capacitive elements changes when performing input operations by contacting the capacitive elements with a finger or an input tool
Data Source
AI summary
A sensing unit performs a first sensing process of sensing an approach or a contact of an object to a display panel by collectively sensing electrostatic capacitance of each of a plurality of sensing electrodes provided in a matrix pattern. Further, in a case where the approach or the contact of the object has not been sensed in the first sensing process, the sensing unit repeats the first sensing process, and in a case where the approach or the contact of the object has been sensed in the first sensing process, the sensing unit performs a second sensing process of sensing a position of the object by individually sensing the electrostatic capacitance of each of the plurality of sensing electrodes.