Common-Electrode Drive Circuit Bundled Touch Control
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Solution Overview
Problem
Conventional in-cell display devices require significant modifications to achieve bundled drive in touch operations, which complicates the display device architecture and increases manufacturing costs due to the need for complex drive circuits and high-cost CMOS transistors.
Innovation Solution
The implementation of a display device with a common-electrode drive circuit comprising shift registers and switch circuits, which uses four-phase clock signals to control the drive of common electrodes in bundles, allowing for efficient touch-drive operations without the need for CMOS transistors, thereby simplifying the drive circuit and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional in-cell display devices use bundled drive in touch operations, then touch detection performance is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent divides the common electrodes into multiple groups (first group and second group) that can be driven independently or in bundles. This segmentation allows flexible drive modes including bundled drive for improved touch detection while avoiding the need for completely complex drive circuits. The common electrode drive circuit includes separate drive circuits for each group, enabling selective activation of bundled drive only when needed.
Solution Approach 2:
The patent implements dynamic drive mode switching where the display device can operate in different modes: normal drive mode for display operations and bundled drive mode for touch detection operations. The system dynamically selects which group of common electrodes to drive based on the operational requirements, allowing optimization of touch detection performance without permanently increasing device complexity.
2Reliability
If conventional in-cell display devices implement bundled drive, then touch detection performance is improved, but manufacturing cost increases due to CMOS transistors
Solution Approach 1:
The patent replaces expensive CMOS transistors with conventional transistors (such as TFTs - thin film transistors) in the common electrode drive circuit. This substitution significantly reduces manufacturing costs while still enabling bundled drive functionality. The conventional transistors are sufficiently reliable for the intended application and can be manufactured using standard display manufacturing processes without requiring costly CMOS fabrication.
Solution Approach 2:
The patent changes the transistor type parameter from CMOS to conventional transistor (TFT), which fundamentally alters the manufacturing cost characteristic. This parameter change allows the device to achieve bundled drive capability through standard manufacturing processes, eliminating the need for specialized high-cost CMOS fabrication while maintaining the essential functionality for improved touch detection.
3Reliability
If conventional in-cell display devices use bundled drive, then touch detection performance is improved, but drive circuit complexity increases
Solution Approach 1:
The patent merges the display function and touch detection function by using the common electrodes for both purposes. The same common electrode drive circuit is used to drive common electrodes during display operations and to enable bundled drive for touch detection. This merging eliminates the need for separate drive circuits, reducing overall drive circuit complexity while still achieving improved touch detection performance through bundled drive capability.
Solution Approach 2:
The common electrode drive circuit is designed with multi-functionality, serving both display driving and touch detection enabling functions. The drive circuit can operate in different modes (normal drive and bundled drive) depending on the operational requirements. This universal design allows the circuit to achieve improved touch detection performance without requiring dedicated complex hardware, as the same circuit structure adapts to different operational modes.
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 solution enables efficient bundled drive of common electrodes, improving touch detection performance while reducing the complexity and cost of the drive circuit, allowing for cost-effective production and efficient operation of in-cell touch panels.
Implementation Method 1
each of the shift registers being configured to transfer a shift signal
Implementation Method 2
each of the switch circuits being configured to connect a signal line from the driver to a common electrode or electrodes of an associated block based on a shift signal output from an associated shift register
Implementation Method 3
a capacitive touchpanel is known in which electrodes formed to extend in a single direction are arranged in such a way as to intersect other electrodes formed to extend in another direction. In this touchpanel, the electrodes are connected to a control circuit, and are supplied with an excitation current from the control circuit, to thereby detect an object located in proximity to them.
Data Source
AI summary
According to one embodiment, a display device includes common electrodes, detection electrodes, a common-electrode drive circuit including shift registers and switch circuits electrically connected to the shift registers, and a driver which outputs four-phase clock signals and a touch-drive signal, wherein a reset operation of the each shift register is controlled by predetermined two of the four-phase clock signals, each of the switch circuits connects a signal line from the driver to common electrodes based on a shift signal output from an associated shift register, and the each switch circuit causes the touch-drive signal from the driver to be supplied to the common electrodes of the block during a period from time at which the shift signal is output from the associated shift register to time at which a predetermined one of the four-phase clock signals is input.