AMOLED Pixel Circuit Touch Integration via Shared TFTs
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Solution Overview
Problem
The integration of a Touch Screen Panel (TSP) in Cell circuit into an Active Matrix Organic Light Emitting Diode (AMOLED) pixel unit circuit is hindered by lack of space for additional Thin-Film Transistors (TFTs) and signal lines, which are required to maintain functionality.
Innovation Solution
An active matrix organic light emitting diode pixel unit circuit is designed with specific modules such as a light emitting module, driving module, threshold compensation module, light emitting control module, touch sensing module, and sensing signal output module, utilizing common data lines and control signals to integrate the TSP in Cell circuit, including additional TFTs and capacitors, while optimizing circuit components and signal operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If TSP in Cell circuit is integrated into AMOLED pixel unit circuit, then touch screen functionality is achieved, but circuit space is insufficient for additional TFTs and capacitors
Solution Approach 1:
The patent merges the TSP sensing circuit functions into the existing AMOLED pixel circuit by having the photodiode share the pixel electrode structure and by integrating sensing capacitors with the existing storage capacitor. The photodiode is formed on the pixel electrode without requiring separate dedicated space, and the sensing operations utilize the same TFTs and signal lines already present in the AMOLED circuit, thereby achieving touch functionality without adding extra circuit components that would consume additional space.
Solution Approach 2:
The patent implements multi-functionality by designing the photodiode to serve dual purposes: as part of the pixel structure for light emission and as a light-induced sensor for touch detection. The existing storage capacitor is also utilized as a sensing capacitor. The same TFTs and control signals are used for both display driving and touch sensing operations, eliminating the need for separate dedicated components and enabling space-efficient integration.
2Reliability
If additional TFTs and capacitors are added to maintain TSP functionality, then touch sensing capability is preserved, but device complexity increases
Solution Approach 1:
The patent combines touch sensing and display functions within the same circuit components. The photodiode is integrated into the pixel electrode structure, the storage capacitor serves dual purposes as both display memory and sensing element, and the same TFTs control both display signaling and sensing operations. This merging approach maintains reliable touch sensing capability while avoiding the complexity increase that would result from adding separate dedicated TSP circuit components.
Solution Approach 2:
The patent achieves reliability in touch sensing by making existing components multi-functional. The photodiode simultaneously serves as part of the OLED pixel structure and as the light-induced sensor. The storage capacitor functions as both the memory element for grayscale display and as the sensing capacitor for touch detection. This universal usage of components ensures reliable touch functionality without increasing device complexity.
3Area of stationary object
If common data lines and control signals are used for both AMOLED and TSP functions, then space is optimized, but signal interference may occur
Solution Approach 1:
The patent employs periodic action by implementing time-division multiplexing where touch sensing and display driving operations are performed in alternating time periods. During sensing periods, the photodiode and sensing capacitors are activated while display updating is paused. During display periods, the pixel circuits operate normally for light emission. This periodic separation of operations allows common data lines and control signals to be used without causing signal interference, as the two functions do not operate simultaneously on the same signal paths.
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 configuration allows for the successful integration of a touch screen functionality into the AMOLED pixel unit circuit, enhancing the display panel's capabilities without compromising existing components, enabling efficient touch sensing and light emission.
Implementation Method 1
the sensor senses light using a photodiode D1 and generates electric leakage to detect a touch signal
Implementation Method 2
the sensor senses light using a sensitive capacitor C2 and detects the touch signal by the coupling of the sensitive capacitor and the change of the capacitor
Implementation Method 3
Thin-Film Transistor (TFT) T1 functions as an amplifying transistor to amplify the voltage change across D1 after detecting the touch signal, increase the driving capability of the TSP in Cell circuit output
Implementation Method 4
Active Matrix Organic Light Emitting Diode (AMOLED) has a faster response speed, a higher contrast ratio and a wider angle of view as compared with a traditional liquid crystal panel. AMOLED Pixels are driven to emit light by a relevant driving circuit on the array substrate
Data Source
AI summary
The present invention provides an active matrix organic light emitting diode, AMOLED pixel unit circuit and a display panel for integrating a touch screen circuit into the AMOLED pixel unit circuit, and manufacturing an AMOLED display panel having the functionality of a touch screen. The AMOLED pixel unit circuit comprises a driving module, configured to amplify a induction signal generated by a touch sensing module, output the induction signal through a induction signal output module, and drive a light emitting module; the light emitting control module, configured to control the light emitting module to emit light; a threshold compensation module, configured to compensate a threshold voltage of the driving module; a charging module, configured to charge the threshold compensation module; the touch sensing module, configured to generate the induction signal and output the induction signal to the driving module; and the induction signal output module, configured to output the induction signal amplified by the driving module.