Touch Electrode Block Driving to Shrink Capacitive Sensor Circuits
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Solution Overview
Problem
As larger display devices are manufactured, the area occupied by touch drivers in capacitive touch screens increases, necessitating a reduction in the number of touch drivers to maintain efficiency and compactness.
Innovation Solution
The input sensing unit incorporates a touch sensing unit with a plurality of driving electrodes and sensing electrodes, where touch drivers are connected in blocks, and a driving signal generating unit that includes digital-to-analog converters and switch units to provide driving signals based on a Hadamard matrix, reducing the number of touch drivers required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If touch drivers are connected one-to-one to driving electrodes, then each driving electrode can be controlled independently, but the area occupied by touch drivers increases
Solution Approach 1:
Multiple driving electrodes are grouped into blocks, and a single touch driver controls multiple driving electrodes within each block through block control signals. This merging approach reduces the total number of touch drivers required while maintaining the ability to independently control each block of electrodes.
Solution Approach 2:
The set of driving electrodes is divided into multiple blocks, where each block is controlled by a dedicated touch driver. This segmentation allows the system to manage large numbers of electrodes with fewer drivers by organizing them into manageable groups that can be controlled independently.
2Area of stationary object
If the number of touch drivers is reduced, then the area occupied by the driving signal generating unit decreases, but the complexity of signal distribution increases
Solution Approach 1:
The system uses periodic block control signals to sequentially activate different blocks of driving electrodes. Each touch driver operates in periodic cycles, controlling its assigned block during specific time intervals. This periodic operation simplifies the signal distribution architecture compared to continuous independent control of all electrodes.
Solution Approach 2:
The touch drivers prepare and distribute control signals to blocks of driving electrodes in advance according to a predetermined block control pattern. This preliminary organization of signal distribution reduces the real-time complexity by pre-establishing the control architecture and signal routing patterns.
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 configuration reduces the area occupied by the driving signal generating unit, allowing for more compact and efficient operation of the input sensing unit while maintaining effective touch detection.
Implementation Method 1
a digital-to-analog converter configured to provide a first signal or a second signal
Implementation Method 2
an ath normal switch unit disposed between the first buffer and the touch drivers, and an ath inversion switch unit disposed between the second buffer and the touch drivers
Implementation Method 3
when one or more pointers such as a person's finger touch a surface of a input sensing unit a position of a contact surface can be determined by detecting a change in capacitance formed in a sensing cell (node)
Data Source
AI summary
An input sensing unit includes a touch sensing unit, which includes a plurality of driving electrodes, a plurality of sensing electrodes, and a driving signal generating unit which provides driving signals to the driving electrodes. The sensing electrodes are insulated from and intersect the driving electrodes. The driving signal generating unit includes touch drivers connected to driving electrodes and a digital-to-analog converter configured to provide a first signal or a second signal, and each of the touch drivers is connected to a preset number of driving electrodes among the driving electrodes.