Touch Display Device Using Enable Electrodes for Capacitive Sensing
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Solution Overview
Problem
Current touch display devices require discrete layers for display and touch sensing, leading to increased production costs, complexity, and device thickness, as well as limitations in providing touch sensing functionality to modular active matrix display panels not natively designed with in-cell touch sensors.
Innovation Solution
The approach involves utilizing enable electrodes in an active matrix display panel for both image display and capacitive touch sensing by driving them with different voltages, eliminating the need for a discrete transmit electrode layer and its adhesive layer, thereby reducing production costs and device thickness while enabling touch sensing functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete layers are used for display and touch sensing, then touch sensing functionality is provided, but production costs increase and device thickness increases
Solution Approach 1:
The patent merges the display function and touch sensing function into a single integrated structure by using the enable electrodes of the active matrix display panel to serve dual purposes. The enable electrodes are driven with different voltages to perform either display activation or capacitive coupling for touch sensing, eliminating the need for separate discrete transmit electrode layers and reducing overall device complexity and thickness.
Solution Approach 2:
The enable electrodes in the display panel are designed to perform multiple functions: they can be driven with a first voltage to activate display cells for image display, or driven with a second voltage to produce capacitive coupling with receive electrodes for touch sensing. This multi-functionality eliminates the need for dedicated touch sensing electrodes, reducing production costs and device thickness while maintaining effective touch sensing capabilities.
2Reliability
If discrete transmit electrode layer is added, then touch sensing is enabled, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the display electrode structure with the touch sensing transmit electrode function by utilizing the existing enable electrodes. This merging eliminates the need for a separate discrete transmit electrode layer and its adhesive layer, directly reducing manufacturing steps, production costs, and complexity while maintaining effective touch sensing capability through capacitive coupling.
Solution Approach 2:
The enable electrodes are designed with universal functionality to serve both display and touch sensing purposes. By driving these electrodes with different voltages, the system can switch between display mode and touch sensing mode, eliminating the need for separate manufacturing processes for discrete touch electrodes and reducing overall manufacturing complexity and cost.
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 method allows for reduced production costs and device thickness while providing effective touch sensing capabilities to active matrix display panels, even those not natively designed with in-cell touch sensors, by using existing enable electrodes for both display and touch sensing, enhancing the signal-to-noise ratio and accuracy of touch input detection.
Implementation Method 1
driving a second enable electrode different than the first enable electrode with a transmit voltage that does not activate the display cells coupled to the second enable electrode and produces a capacitive coupling between the second enable electrode and one or more of the plurality of receive electrodes
Data Source
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AI summary
A touch display device includes a display panel, a plurality of receive electrodes, an enable electrode driver, and a touch sense circuit. The display panel includes a plurality of data electrodes and a plurality of enable electrodes connected to a plurality of display cells. Each display cell is connected to a pair of an enable electrode and a data electrode. The enable electrode driver drives a first enable electrode with a display voltage to activate display cells coupled to the first enable electrode, and drives a second enable electrode different than the first enable electrode with a transmit voltage to produce a capacitive coupling between the second enable electrode and a receive electrode. The touch sense circuit is configured to recognize a touch input to the touch display device based on a change in capacitance between the second enable electrode and the receive electrode.