Photodiode-Integrated Pixel Circuit for Optical Touch Detection
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Solution Overview
Problem
Current styluses for large-screen devices have large tip sizes, leading to low touch accuracy and wear on the display screen due to physical contact, which affects user experience.
Innovation Solution
Integration of a photodiode in the pixel circuit of a display panel, allowing for optical touch detection using a laser pointer without physical contact, enabling pixel-level positioning and reducing wear on the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a passive capacitive stylus with a wide conductive tip is used to simulate touch effect, then the touch detection function is achieved, but the touch accuracy is low and the screen experiences wear from physical contact
Solution Approach 1:
The patent replaces the mechanical contact-based touch detection system with an optical detection system. Instead of using a physical stylus tip that contacts the screen, the invention uses a laser pointer to emit light that is detected by a photodiode integrated into the pixel circuit, thereby eliminating mechanical wear while maintaining touch detection functionality
Solution Approach 2:
The patent introduces light as an intermediary medium between the user's touch input and the touch detection system. The laser pointer emits light that travels through air to the display screen, where it is detected by the photodiode, replacing the direct mechanical contact between stylus and screen
2Measurement precision
If an active capacitive stylus with integrated touch detection circuit is used, then the touch function is realized, but the tip size remains large resulting in low touch accuracy
Solution Approach 1:
The patent merges the touch detection function with the existing pixel circuit by integrating a photodiode into the pixel circuit structure. This allows the display panel itself to perform touch detection without requiring a separate active stylus with integrated circuits, thereby reducing device complexity while improving touch accuracy
Solution Approach 2:
The patent makes the display panel multi-functional by enabling it to serve both as the display output device and as the touch detection sensor. The photodiode integrated in the pixel circuit allows the same display structure to detect optical touch signals, eliminating the need for separate touch detection hardware
3Measurement precision
If optical touch detection with photodiode integrated in pixel circuit is implemented, then touch accuracy improves to pixel-level precision, but the wiring complexity of the display panel increases
Solution Approach 1:
The patent combines the photodiode with the existing pixel circuit structure, sharing common electrical connections and signal lines. The photodiode's output is integrated into the pixel circuit's existing data lines and control signals, thereby achieving pixel-level touch detection without adding separate wiring infrastructure
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
Improves touch accuracy to pixel-level precision and eliminates wear on the display screen by using optical touch detection, enhancing user experience and simplifying the display panel's wiring.
Implementation Method 1
at least one pixel circuit, at least one light-emitting device coupled to the pixel circuit... One pixel circuit of the at least one pixel circuit includes a data writing transistor and a photodiode
Data Source
AI summary
A display panel and a method for driving the same, and a display apparatus are provided. The display panel includes at least one pixel circuit, at least one light-emitting device coupled to the pixel circuit, at least one data line, and a first voltage signal line. One pixel circuit of the at least one pixel circuit includes a data writing transistor and a photodiode. The data writing transistor includes a first electrode coupled to one of the at least one data line, and a second electrode coupled to a first electrode of the photodiode. The photodiode includes a second electrode coupled to the first voltage signal line.