Dual Gate TFT Pixel Circuit for Integrated Display and Fingerprint Sensing
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Solution Overview
Problem
Display apparatuses combining image display and fingerprint recognition face reduced pixel density due to both functions being performed by individual thin film transistors (TFTs), hindering high-resolution display effects.
Innovation Solution
A dual gate thin film transistor is used, where the photosensitive device is indirectly connected to one of the gates, allowing the transistor to work in a sub-threshold region for fingerprint recognition and an on-state for pixel display, reducing the number of TFTs required and enhancing signal intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If individual thin film transistors are used for both image display and fingerprint recognition, then both functions can be implemented, but pixel density is greatly reduced
Solution Approach 1:
The patent implements a dual-gate thin film transistor where one gate controls the photosensitive device for fingerprint recognition while the other gate controls the organic light emitting device for image display. This multi-functional transistor design allows a single device to perform both fingerprint sensing and pixel display functions, thereby increasing pixel density without sacrificing functional versatility
Solution Approach 2:
The patent merges the fingerprint recognition function and image display function into a single pixel circuit by integrating a photosensitive device and an organic light emitting device within the same pixel structure, controlled by the dual-gate transistor. This consolidation reduces the number of separate components needed per pixel, thereby improving pixel density
2Reliability
If individual thin film transistors are used for fingerprint recognition and image display, then both functions operate independently, but the number of TFTs increases
Solution Approach 1:
The dual-gate thin film transistor serves multiple functions: one gate controls the photosensitive device for fingerprint recognition while the other gate controls the organic light emitting device for image display. This multi-functional design reduces the total number of TFTs required in the pixel circuit while maintaining reliable independent control of both functions through separate gate signals
3Device complexity
If a dual gate transistor is used for both photosensitive device and organic light emitting device, then the number of TFTs is reduced, but control complexity increases
Solution Approach 1:
The dual-gate transistor control is segmented into two independent gate control paths: one gate receives control signals for photosensitive device operation (fingerprint recognition mode), while the other gate receives control signals for organic light emitting device operation (display mode). This segmentation allows independent control of each function without interference, simplifying the overall control logic despite the reduced component count
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 high-resolution displays by using a single dual gate transistor as a switch for both the photosensitive device and the organic light emitting device, improving fingerprint detection sensitivity and maintaining pixel display functionality.
Implementation Method 1
the photosensitive device converts an optical signal into an electric charge in response to the optical signal detected
Data Source
AI summary
The present application discloses a semiconductor apparatus, a pixel circuit and a control method thereof. The semiconductor apparatus comprises: an active layer; a first insulating layer; a first gate and a second gate overlapping with a portion of the active layer with the first insulating layer interposed therebetween, respectively; a first electrode, a second electrode and a third electrode, the first electrode and the second electrode are electrically connected with a first portion and a second portion of the active layer, respectively, the third electrode is used to be electrically connected with a photosensitive device, wherein the third electrode is electrically connected with the first gate or the second gate; or the third electrode is electrically connected with a third portion of the active layer.