Touch-Control Pixel-Driving Circuit for AMOLED Displays
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Solution Overview
Problem
Conventional AMOLED displays lack the capability to integrate touch-control functions, limiting their functionality beyond simple image display, and existing touch technologies like capacitive touch are not suitable for providing high sensitivity and remote laser pen control.
Innovation Solution
A touch-control pixel-driving circuit is introduced, incorporating a light-sensing touch sub-circuit and a driving sub-circuit that uses a photo transistor to sense light changes and generate signals for touch detection, allowing for both finger and laser pen control, while reducing the complexity of implementing touch control by minimizing the number of scan lines required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional AMOLED display is used with a simple pixel-driving circuit, then the manufacturing cost is low and the structure is simple, but the display apparatus lacks touch-control function
Solution Approach 1:
The patent merges the touch-sensing function and display driving function into a single integrated pixel-driving circuit. The light-sensing touch sub-circuit is combined with the driving transistor and OLED, allowing the same pixel structure to perform both touch detection and light emission without requiring separate touch sensor modules
Solution Approach 2:
The pixel-driving circuit is designed to perform multiple functions: it drives the OLED for display and simultaneously detects touch events through the light-sensing sub-circuit. The read line serves dual purposes by carrying both display signals and touch sensing signals, making the circuit universal for both display and touch control operations
2Measurement precision
If capacitive touch technology is used in AMOLED display, then touch control function is added, but the sensitivity is insufficient and remote laser pen control is not achieved
Solution Approach 1:
The patent replaces capacitive touch detection with an optical detection system. Instead of measuring electrical capacitance changes, the light-sensing touch sub-circuit uses a photo transistor to detect light intensity changes, enabling high-sensitivity touch detection and remote laser pen control through optical signal variations
Solution Approach 2:
The patent changes the detection parameter from electrical capacitance to light intensity. By monitoring changes in light intensity at the OLED pixel, the system can detect both direct finger touches and remote laser pen pointers with high precision, overcoming the sensitivity limitations of capacitive technology
3Measurement precision
If a light-sensing touch sub-circuit is integrated into the pixel-driving circuit, then touch sensitivity and remote control are improved, but the number of scan lines and circuit complexity increase
Solution Approach 1:
The read line is designed to serve dual purposes: it carries data signals for OLED driving during display periods and carries touch sensing signals during touch detection periods. This multi-functional use of the read line eliminates the need for separate touch sensor scan lines, maintaining a simple overall structure while enabling advanced touch functionality
Solution Approach 2:
The circuit operates in periodic cycles, alternating between display mode and touch sensing mode. During display periods, the read line drives OLED pixels; during touch periods, the same read line collects touch sensing signals. This time-division multiplexing allows one circuit to perform multiple functions without requiring additional physical lines
4Device complexity
If the same pixel-driving circuit is used for both display and touch sensing, then the structure is simplified, but the control signals and timing become more complex
Solution Approach 1:
The control system uses periodic timing signals to switch between display and touch sensing operations. Control signals are generated in periodic cycles that alternately activate the driving transistor for display and the photo transistor for touch sensing, automating the multi-functional operation through time-division multiplexing
Solution Approach 2:
The read line provides feedback signals that carry both display status information and touch event detection results. The control system monitors these feedback signals to automatically adjust operation modes, enabling intelligent switching between display and touch functions without complex manual control
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
Enables AMOLED displays to support both image display and touch-control functions using light-sensitive technology, providing high sensitivity and independence from touch sensor module dimensions, and allowing for remote laser pen control without affecting image display quality.
Implementation Method 1
The light-sensing-touch sub-circuit is configured to be reset by a first control signal and a second control signal to send a raw signal to the read line based on a high-level voltage at the data line, and to generate a sensing signal depended on a change of the raw signal due to a touch
Data Source
AI summary
The present application discloses a touch-control pixel-driving circuit. The circuit includes a driving transistor coupled to a data line and a read line; an organic light-emitting diode (OLED) coupled to the driving transistor. The circuit also includes a light-sensing-touch sub-circuit coupled to the data line and the read line and configured to be reset by a first and a second control signals to send a raw signal flour the data line to the read line, and to generate a sensing signal depended on a change of the raw signal due to a touch and send the sensing signal to the read line. Further, the circuit includes a driving sub-circuit coupled to the driving transistor and configured to charge and discharge the driving transistor using a power-supply voltage and a data signal controlled by the first, the second, and a third control signals, and to drive the OLED for emitting light.