Liquid Crystal Display Touch Detection Electrode Control
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Solution Overview
Problem
Existing liquid crystal display devices with touch detection functions using electrostatic capacitance type methods are limited in their ability to adopt various drive methods, which restricts flexibility and efficiency in detecting external proximity objects.
Innovation Solution
A liquid crystal display device with a touch detection function that includes a plurality of touch detection drive electrodes and a control system allowing for the selection and control of drive signals using multiple switches and voltage sources, enabling flexible drive methods and improved detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a touch detection device uses an electrostatic capacitance type method with multiple drive electrodes and detection electrodes, then the detection function is achieved, but the device structure becomes complex and power consumption increases
Solution Approach 1:
The patent combines the drive electrode and detection electrode functions into a single electrode structure. The same electrode serves dual purposes: acting as a drive electrode during display periods and as a detection electrode during touch detection periods, thereby reducing the total number of electrodes and simplifying the device structure while maintaining touch detection functionality
Solution Approach 2:
The electrode is designed to perform multiple functions - it serves as both a drive electrode for liquid crystal display operation and a detection electrode for touch detection. This multi-functionality eliminates the need for separate electrode systems, reducing structural complexity and power consumption
2Measurement precision
If drive signals are supplied to multiple drive electrodes simultaneously, then detection coverage is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic switching between display periods and touch detection periods. During touch detection periods, drive signals are supplied to electrodes in a time-division manner rather than simultaneously, allowing multiple electrodes to be activated sequentially. This periodic action ensures comprehensive detection coverage while significantly reducing power consumption compared to simultaneous activation
3Device complexity
If the touch detection device integrates closely with the liquid crystal display structure, then the overall device size is reduced, but the drive method flexibility is limited
Solution Approach 1:
The patent employs dynamic control through a control device that can flexibly switch between different drive methods. The system can operate in various modes including supplying drive signals to all drive electrodes, supplying to selected drive electrodes, or adjusting signal parameters dynamically. This dynamic adaptability is achieved through time-division control and selective signal routing, maintaining integration benefits while enabling diverse drive strategies
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 solution allows for effective detection of external objects by enabling flexible drive signal management and enhanced touch detection accuracy, reducing power consumption and simplifying the device structure.
Implementation Method 1
proximity of an external object is detected using a fact that a value of a capacitance in an intersection part in which a drive electrode and a detection electrode intersect with each other changes due to an external object such as a finger coming close
Data Source
AI summary
To provide a liquid crystal display device with a touch detection function in which any drive method can be adopted. The liquid crystal display device is provided with: a liquid crystal element arrangement that has a plurality of liquid crystal display elements arranged in a matrix shape; a plurality of scanning lines that are arranged in each row of the liquid crystal element arrangement, and supply scanning signals to a plurality of liquid crystal display elements arranged in a corresponding row; a plurality of signal lines that are arranged in each column of the liquid crystal element arrangement, and supply an image signal to a plurality of liquid crystal display elements arranged in a corresponding column; a plurality of touch detection drive electrodes which are arranged in a column of the liquid crystal element arrangement, and to which a drive signal for detecting a touch is supplied; and a touch control part that specifies a touch detection drive electrode from the a plurality of touch detection drive electrodes. Here, the drive signal is supplied to the touch detection drive electrode specified by the touch control part.