In-Display Fingerprint Electrode Layout for Low-Resolution Screens
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Solution Overview
Problem
Existing fingerprint recognition technologies struggle to integrate into display areas of low-resolution displays without a touch function, limiting their application and precision, especially in devices like small-sized visual fingerprint readers and car display screens.
Innovation Solution
A display screen design incorporating a thin film transistor array substrate, color filter substrate, and liquid crystal layer, with separate fingerprint recognition electrodes and signal lines, enabling full-screen multi-block recognition without time-division scanning, using indium tin oxide for pixel electrodes and metal for signal lines, and integrating fingerprint recognition into the display area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If capacitive fingerprint recognition technology is used to reduce device size, then device size is reduced, but fingerprint recognition precision deteriorates in low-resolution displays
Solution Approach 1:
The display screen is divided into multiple independent fingerprint recognition blocks distributed across the display area. Each block contains fingerprint recognition electrodes that can independently detect fingerprint information. This segmentation allows the system to achieve high-precision fingerprint recognition by combining data from multiple blocks, overcoming the limitation of low-resolution displays while maintaining a compact device form factor.
2Device complexity
If in-cell touch panel with time-sharing scanning is used to integrate functions, then device complexity is reduced, but application versatility deteriorates for low-resolution displays without touch function
Solution Approach 1:
The fingerprint recognition electrodes are integrated directly into the display screen structure, allowing the display to serve multiple purposes: visual display and fingerprint recognition. This multi-functional design enables low-resolution displays without touch functionality to acquire fingerprint recognition capability, significantly expanding application versatility while avoiding the complexity of time-sharing scanning systems.
3Device complexity
If fingerprint recognition is integrated into display area, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The fingerprint recognition electrodes are merged with the display electrode structure, sharing the same ITO layer and substrate. This merging approach allows both display and fingerprint recognition functions to be achieved using the same manufacturing processes and materials, reducing the need for additional precise alignment and assembly steps, thereby lowering manufacturing precision requirements despite the integrated design.
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 high-precision fingerprint recognition across full screens without a touch function, expanding application diversity and improving cost-performance, while enhancing user experience.
Implementation Method 1
a liquid crystal layer sandwiched between the TFT array substrate and the CF substrate
Implementation Method 2
use the finger as an electrode of the capacitor and the fingerprint sensor as the other electrode to form a grayscale image based on the capacitance difference between the ridge and valley with respect to the smooth fingerprint sensor
Data Source
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AI summary
A display screen and an electronic device. The display screen is provided with one or more fingerprint recognition blocks (5) within an effective display region (AA). In each fingerprint recognition block (5): a pixel electrode layer (11) corresponding to each sub-pixel unit (SP) comprises a sub-pixel electrode (111), and a fingerprint recognition electrode (112) separated from the sub-pixel electrode (111); a black matrix layer (21) corresponding to each sub-pixel unit (SP) comprises a black border (211) that covers the circumferential edges of the sub-pixel electrode (111), and a black block (212) that completely covers the fingerprint recognition electrode (112); a fingerprint recognition signal line (13) is provided to contact the fingerprint recognition electrode (112), and to electrically connect the fingerprint recognition electrode (112) to a display and fingerprint recognition integrated chip (9). According to the present invention, a fingerprint recognition function can be integrated in a display region with low resolution and without a touch function of a display screen, and fingerprint recognition in a plurality of blocks on the entire display screen can be achieved without time-sharing scanning.