Hybrid Touchscreen Common Electrode for Dual Sensing
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Solution Overview
Problem
Existing touchscreen technologies face challenges in integrating both touch-sensing and light-sensing capabilities into a single in-cell type touchscreen apparatus without increasing complexity, while maintaining efficient operation and sensitivity.
Innovation Solution
The apparatus employs a common electrode that functions as both a display electrode and a sensing electrode, utilizing gate signals to activate and reset sensing units, and incorporates oxide semiconductor transistors for light sensing, with a reset transistor and switch transistors to manage voltage and sensing currents, allowing for dual sensing modes with minimal additional complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If separate touch panel and display panel are integrated into in-cell type, then device complexity is reduced, but integrating both touch-sensing and light-sensing capabilities increases complexity
Solution Approach 1:
The common electrode serves multiple functions: it acts as a display electrode during normal operation and as a sensing electrode for both touch-sensing and light-sensing operations. This multi-functionality allows the apparatus to achieve dual sensing capabilities without adding separate dedicated electrodes for each function, thereby maintaining structural simplicity while enabling versatile operation modes.
Solution Approach 2:
The system dynamically switches between different sensing modes (touch-sensing and light-sensing) by controlling the activation state of sensing units through gate signals. The common electrode's role transitions between display and sensing functions based on operational requirements, allowing the apparatus to adapt its behavior without permanent structural changes or additional components.
2Device complexity
If common electrode is used for both display and sensing, then device complexity is reduced, but sensing sensitivity and operation efficiency may deteriorate
Solution Approach 1:
The sensing functionality is segmented into separate sensing units that can be independently activated or reset using gate signals. This segmentation allows the common electrode to be selectively used for sensing operations without permanently compromising its display function, maintaining both structural simplicity and sensing precision through controlled activation of specific sensing regions.
Solution Approach 2:
Reset circuits are implemented to initialize the voltage of the common electrode before sensing operations. This preliminary action ensures that the electrode is in the appropriate voltage state for accurate sensing, thereby maintaining sensing sensitivity despite the electrode's dual role in display and sensing functions.
3Device complexity
If gate signals activate one sensing unit and reset another, then device complexity is minimized, but operation control complexity increases
Solution Approach 1:
The gate signals are applied in periodic sequences to alternately activate and reset different sensing units. This periodic activation pattern simplifies the control logic by establishing a regular timing scheme for switching between sensing modes, making the operation control more predictable and manageable despite the dual-function requirements.
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 a hybrid touchscreen that efficiently performs both touch-sensing and light-sensing operations with improved sensitivity and reduced complexity, allowing for a more compact and efficient design suitable for large display devices.
Implementation Method 1
a light-sensing unit for sensing an intensity of light incident on the touchscreen apparatus
Implementation Method 2
a touch-sensing unit for sensing a position of a touch on the touchscreen apparatus
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
An touchscreen apparatus includes pixel rows including pixels configured to display an image, a touch-sensing unit configured to sense a physical touch and a light-sensing unit configured to sense incident light, the touch-sensing unit and the light-sensing unit being between two adjacent pixel rows and configured to operate based on first and second gate signals, a first sensor gate line (SGLn) connected to the light-sensing unit and the touch-sensing unit and configured to provide the first gate for activating the light-sensing unit and resetting the touch-sensing unit, a second sensor gate line (SGLn+1) connected to both the light-sensing unit and the touch-sensing unit and configured to provide the second gate signal for activating the touch-sensing unit and resetting the light-sensing unit, and a reset circuit configured to provide a common voltage to the pixels based on the operation of at least one of the light-sensing unit and the touch-sensing unit.