Optical Touch Device With Frequency-Modulated Pixel Arrays
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Solution Overview
Problem
Existing optical touch technologies based on OLEDs face challenges such as OLED materials being sensitive to high temperatures, signal coupling due to EM signals having the same frequency as light signals, and difficulties in integrating light modulation into displays due to ambient light interference and saturation issues.
Innovation Solution
An optical touch device with a pixel array and light receiving array that emits detection rays with a preset frequency, using a detection circuit to process sensing signals from light receivers, thereby avoiding signal coupling and improving detection accuracy, and integrating display and touch functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If OLED materials are used for optical touch display, then display functionality is achieved, but OLED materials are sensitive to high temperatures causing reliability issues
Solution Approach 1:
The device segments the display and touch detection functions into separate components: a display unit (which can be OLED) and a touch detection unit with independent light source and sensor arrays. This segmentation allows the OLED display to operate without exposure to high-temperature detection processes, preserving its reliability while maintaining display functionality.
Solution Approach 2:
The patent introduces an intermediary structure - a touch sensor layer with independent light-emitting elements and light sensors positioned between the OLED display and the user interface. This intermediary layer performs touch detection using its own light source, preventing direct thermal interaction between the detection process and the OLED materials, thus protecting OLED reliability.
2Device complexity
If EM signals and light signals have the same frequency, then signal processing is simplified, but signal coupling occurs causing interference
Solution Approach 1:
The patent employs dynamic frequency modulation where the light-emitting elements are driven to emit light at specific frequencies that are modulated over time. The detection circuit uses synchronous demodulation techniques to distinguish the modulated light signals from unmodulated EM signals, dynamically separating the signal frequencies to prevent coupling while maintaining processing efficiency.
Solution Approach 2:
The light-emitting elements emit light in periodic pulses with specific duty cycles and frequencies. This periodic action creates distinct temporal patterns in the light signals that can be easily differentiated from continuous EM signals through time-based detection methods, reducing signal coupling while keeping the detection system relatively simple.
3Adaptability or versatility
If light modulation is integrated into display, then integration level increases, but ambient light interference and saturation issues occur
Solution Approach 1:
The patent implements preliminary compensation by measuring ambient light conditions and pre-adjusting the detection thresholds and signal processing parameters before actual touch detection occurs. The system characterizes the ambient light environment and compensates for its effects in advance, preventing saturation and interference from degrading detection accuracy even as integration increases.
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 accurate touch positioning and higher integration levels of display and optical touch, overcoming the limitations of OLED sensitivity and signal interference, and enhancing detection precision.
Implementation Method 1
detection rays with a preset frequency are emitted by the N second pixels
Implementation Method 2
each of the light receivers generates an sensing signal by receiving reflected rays of the detection rays emitted by a corresponding second pixel
Data Source
AI summary
The present disclosure provides an optical touch device and a manufacturing method thereof, a display and an electronic device, wherein the optical touch device comprises: a pixel array (11) that comprises a plurality of pixel sub-circuits (101) each of which comprises M first pixels (1011) and N second pixels (1012), wherein detection rays with a preset frequency are emitted by the second pixels (1012), where M and N are positive integers; a light receiving array (12) that comprises a plurality of light receivers (121) corresponding, at a one-to-one basis, to the plurality of pixel sub-circuits (101), wherein each of the light receivers (121) generates an sensing signal by receiving reflected rays of the detection rays emitted by a corresponding second pixel (1012); and a detection circuit (13) connected with the plurality of light receivers (121), wherein the detection circuit (13) performs touch positioning.