Touch Detection Noise Filtering via Frequency Adjustment
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Solution Overview
Problem
Display devices with touch detection functions face malfunctions due to disturbance noises, which can cause false touch detections, and existing solutions that separate noise measurement periods from display and touch detection periods lead to reduced performance in both operations.
Innovation Solution
A display device with a touch detection function that integrates a pixel electrode, touch detection electrode, display drive unit, operation drive unit, and a control unit to perform noise detection during the display operation period, allowing for simultaneous noise detection and touch detection in a time divisional manner, using a filter to isolate disturbance noise frequencies and adjust the touch detection drive signal accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate noise measurement period is provided in addition to display operation period and touch detection period, then disturbance noise can be detected, but the time for display operation and touch detection is reduced
Solution Approach 1:
The patent merges the noise measurement function into the display operation period by having the touch detection unit measure disturbance noise during periods when display drive signals are being output. This integration allows noise measurement to occur without requiring a separate dedicated time period, thus maintaining full display and touch detection operation time while still achieving accurate noise measurement for subsequent frequency adjustment.
2Measurement precision
If the frequency of touch detection drive signal is adjusted to avoid disturbance noise frequency, then touch detection accuracy is improved, but the system complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the touch detection unit measures disturbance noise frequency during display operation, the control unit compares the measured noise frequency with the current touch detection drive signal frequency, and adjusts the drive signal frequency accordingly. This closed-loop feedback system automatically optimizes touch detection accuracy by avoiding noise frequencies without requiring complex manual tuning or additional hardware.
Solution Approach 2:
The patent changes the frequency parameter of the touch detection drive signal based on measured disturbance noise characteristics. By dynamically adjusting the drive signal frequency to avoid frequencies where disturbance noise peaks occur, the system improves touch detection accuracy while using simple frequency modulation rather than complex system redesign.
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 enhances the accuracy of touch detection by reducing false positives from disturbance noises and maintains the performance of both display and touch detection operations by integrating noise detection into the display period, preventing degradation in operational time for either function.
Implementation Method 1
The capacitive touch detection device is provided with capacitance between drive electrodes, to which a drive signal is applied, and touch detection electrodes so as to detect a change in capacitance caused by an external object being brought into contact with or proximity to the device
Implementation Method 2
detect a change in voltage waveform that appears on the touch detection electrodes, thereby determining whether or not there is a touch
Data Source
AI summary
According to an aspect, a display device with a touch detection function includes: a pixel electrode; a touch detection electrode; a display drive unit for outputting the pixel signal to the pixel electrode in synchronization with a display drive signal; an operation drive unit for supplying the display drive signal in a display operation period to perform a display operation and supplying a touch detection drive signal in a touch detection period to perform a touch detection operation; a touch detection unit for detecting a detection signal outputted from the touch detection electrode; and a control unit for executing the display operation period and the touch detection period in a time divisional manner. The touch detection unit performs a noise detection operation for detecting a disturbance noise superimposed on the touch detection electrode in the display operation period.