Display Screen TFT-PD Layout for Large-Area Fingerprint Sensing
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Solution Overview
Problem
Existing screen fingerprint recognition technologies are limited by the size of the fingerprint recognition sensor, restricting the operation region and occupying physical space under the display screen, which limits the screen-to-body ratio and device thickness.
Innovation Solution
A display screen with a built-in fingerprint recognition module that includes a thin film transistor (TFT) layer with alternately distributed photo detectors (PDs) and TFTs, integrated with a collimation structure to enhance fingerprint recognition across a larger area without increasing device thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fingerprint recognition sensor is installed under the display screen, then fingerprint recognition function is achieved, but the operation region is limited and the screen-to-body ratio is reduced
Solution Approach 1:
The patent merges the fingerprint recognition sensor with the display screen by integrating photo detectors directly into the TFT layer of the display panel. This combination allows the fingerprint recognition function to be embedded within the display structure itself, enabling large-area or full-screen recognition without requiring a separate sensor module that would reduce the screen-to-body ratio.
Solution Approach 2:
The patent transitions from a planar sensor arrangement under the display to a three-dimensional integration within the TFT layer. By disposing photo detectors on the first inner side surface of the TFT layer with projections alternating with TFTs on the second inner side surface, the system achieves vertical stacking that enables large-area recognition while maintaining a high screen-to-body ratio.
2Adaptability or versatility
If a fingerprint recognition sensor is installed under the display screen, then fingerprint recognition function is achieved, but the device thickness is increased
Solution Approach 1:
The patent embeds the fingerprint recognition components within the existing display screen structure. The photo detectors are nested within the TFT layer, utilizing the internal space of the display panel rather than adding external components. This nesting approach enables fingerprint recognition functionality while maintaining thin device thickness.
Solution Approach 2:
The TFT layer serves multiple functions: it acts as both the driving circuit layer for the display and as the mounting substrate for the photo detectors. This multi-functionality eliminates the need for separate sensor substrates, thereby reducing overall device thickness while achieving fingerprint recognition capability.
3Area of stationary object
If photo detectors are disposed on the TFT layer with alternating distribution, then large-area fingerprint recognition is enabled, but the structural complexity increases
Solution Approach 1:
The patent segments the TFT layer into two distinct surfaces: a first inner side surface for receiving photo detectors and a second inner side surface for receiving TFTs. This segmentation allows independent optimization of each surface for its specific function while maintaining overall structural integrity. The alternating distribution pattern creates a regular, modular structure that manages complexity through repetition.
Solution Approach 2:
Different regions of the TFT layer are assigned different qualities and functions. The first inner side surface is optimized for photo detector placement with specific material properties for light reception, while the second inner side surface is optimized for TFT placement. This local differentiation enables large-area recognition while managing complexity through functional specialization.
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
Enables large-area or full-screen fingerprint recognition with improved precision and security, reducing the internal space and thickness of the device by integrating PDs within the TFT layer and utilizing a collimation structure to optimize light collection.
Implementation Method 1
A plurality of photo detectors (PDs) are disposed on a first inner side surface of the TFT layer. The plurality of PDs convert detected light into electrical signals.
Data Source
Figure 1(a)~1(c)
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AI summary
Embodiments of this application provide a display component. A plurality of thin film transistors TFTs and a plurality of photo detectors PDs are disposed inside the display component. The plurality of PDs convert detected light into electrical signals. The plurality of PDs and the plurality of TFTs are disposed on two opposite inner side surfaces of a same layer of the display component. Projections of the plurality of PDs and the plurality of TFTs on a first plane are alternately distributed, and the first plane is a plane on which the layer at which the plurality of PDs and the plurality of TFT layers are disposed is located. Fingerprint recognition accuracy can be improved by configuring a display screen including the display component provided in the embodiments of this application. In addition, PDs of different quantities are flexibly arranged, to ensure that a large region of the display screen can be used for fingerprint recognition.