Pixel Driving Circuit for AMOLED In-Cell Touch Sensing
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Solution Overview
Problem
Current technologies face challenges in efficiently integrating Active Matrix Organic Light Emitting Diode (AMOLED) display technology with in-cell touch functionality, limiting their application in large-size touch screens and affecting touch sensitivity and uniformity.
Innovation Solution
A pixel driving circuit is designed that combines a display sub-circuit and a photosensitive sub-circuit, sharing signal lines for efficient touch sensing and light emission, using transistors and capacitors to control the light emitting element and sense touch actions, thereby enabling simultaneous display and touch functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AMOLED display technology is integrated with in-cell touch functionality, then touch sensitivity and functionality are improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the AMOLED display sub-circuit and photosensitive touch sub-circuit into a single integrated pixel structure. Both sub-circuits share common components including scan lines, data lines, control lines, and power supply lines, thereby achieving in-cell touch functionality while managing device complexity through resource sharing.
Solution Approach 2:
The pixel driving circuit is designed with multi-functionality to serve both display and touch sensing purposes. The display sub-circuit and photosensitive sub-circuit coexist within the same pixel structure, utilizing shared signal lines and control mechanisms, enabling a single pixel to perform both emission and touch detection functions.
2Reliability
If separate manufacturing processes are used for AMOLED and photosensitive touch, then each technology can be optimized independently, but manufacturing efficiency and cost increase
Solution Approach 1:
The patent combines the manufacturing processes for AMOLED display and photosensitive touch into a single integrated process sequence. The array substrate is manufactured with both sub-circuits formed in the same fabrication flow, eliminating the need for separate manufacturing steps and thereby improving manufacturing efficiency while maintaining technology optimization.
3Device complexity
If photosensitive sub-circuit shares signal lines with display sub-circuit, then device complexity is reduced, but signal interference and threshold voltage drift may occur
Solution Approach 1:
The patent segments the operational phases of the pixel driving circuit into distinct time periods: a first period for photosensitive touch sensing and a second period for display emission. This temporal segmentation allows both sub-circuits to share signal lines without significant interference, as each sub-circuit operates independently during its designated phase, thereby maintaining signal stability while reducing device complexity.
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 integration ensures efficient AMOLED display technology with in-cell touch capabilities, enhancing touch sensitivity and uniformity, and addressing issues related to threshold voltage drift, ensuring consistent image display and prolonged OLED lifespan.
Implementation Method 1
a photosensitive transistor with a gate connected to a source thereof and a drain connected to the second terminal of the first storage capacitor, and configured to sense the photosensitive signal and write the same into the second terminal of the first storage capacitor
Implementation Method 2
a light emitting element, a display sub-circuit and a photosensitive sub-circuit; wherein the display sub-circuit is connected to the data line, the first scan line, the second scan line, the enable control line, the power supply line and the light emitting element, and is configured to drive the light emitting element to emit light for display
Data Source
AI summary
A pixel driving circuit comprises: a data line (Data), a first scan line (Scan[1]), a second scan line (Scan[2]), an enable control line (EM), a power supply line (Vdd), a light emitting element (D), a display sub-circuit (1) and a photosensitive sub-circuit (2); wherein the display sub-circuit (1) is connected to the data line (Data), the first scan line (Scan[1]), the second scan line (Scan[2]), the enable control line (EM), the power supply line (Vdd) and the light emitting element (D), and is configured to drive the light emitting element (D) to emit light for display under the control of the first scan line (Scan[1]), the second scan line (Scan[2]), the enable control line (EM), the data line (Data) and the power supply line (Vdd); and the photosensitive sub-circuit (2) is connected to the data line (Data), the first scan line (Scan[1]), the second scan line (Scan[2]) and the enable control line (EM), and is configured to sense a touch action under the control of the first scan line (Scan[1]), the second scan line (Scan[2]), the enable control line (EM) and the data line (Scan[1]).