Screen-Integrated Fingerprint Sensor Using Display Pixels as Light Sources
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Solution Overview
Problem
Compact mobile devices like smartphones and tablets face challenges in incorporating fingerprint readers due to space constraints while requiring high data security and effective access control.
Innovation Solution
A method and apparatus that utilize a screen with display pixels as light sources and photosensors to optically capture fingerprints, where the display pixels emit light radiation and photosensors capture reflected radiation within a specific scan angle, allowing for both display and fingerprint recognition functions, including the use of infrared and ultraviolet light for improved brightness and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate fingerprint reader is incorporated into mobile devices, then data security and access control are improved, but device complexity and space requirements increase
Solution Approach 1:
The patent combines the fingerprint sensor and display screen into a single integrated structure. The fingerprint sensor is positioned behind the display screen, allowing the screen to serve dual purposes: visual display and biometric authentication. This merging eliminates the need for separate fingerprint reader components, reducing device complexity while maintaining security functionality.
Solution Approach 2:
The display screen is designed to perform multiple functions simultaneously: it acts as both the visual display interface and the fingerprint sensing surface. By making the screen multifunctional, the patent eliminates the need for dedicated security hardware, thereby reducing overall device complexity while preserving data security capabilities.
2Reliability
If a separate fingerprint reader is incorporated into mobile devices, then access control is improved, but installation space requirements increase
Solution Approach 1:
The fingerprint sensor is merged with the display screen structure, utilizing the space behind the screen for sensor placement. This integration allows the fingerprint reading function to be embedded within the existing screen assembly, eliminating the need for additional installation space that would be required for a separate fingerprint reader component.
Solution Approach 2:
The fingerprint sensor is nested within the display screen structure, with the sensor positioned behind the screen surface. This nesting arrangement allows the security function to be housed within the existing screen footprint, maximizing space utilization and eliminating the need for separate installation space for fingerprint recognition hardware.
3Device complexity
If display pixels are used as light sources for fingerprint scanning, then device simplicity is improved, but light radiation control requirements increase
Solution Approach 1:
The display pixels serve dual purposes: they function as both the visual display elements and the light sources for fingerprint illumination. This self-service approach eliminates the need for separate illumination components, simplifying the device structure. The pixels automatically provide the necessary light for fingerprint scanning when activated, reducing the need for additional light radiation control mechanisms.
Solution Approach 2:
The patent recovers the light-emitting function for fingerprint scanning from dedicated illumination components and assigns it to the display pixels instead. By discarding the need for separate illumination hardware and recovering the light-emitting capability within the existing pixel structure, the system achieves simplicity while managing light radiation through standard display control mechanisms.
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 secure fingerprint recognition and document scanning on a thin, flexible screen, providing high data security and multitouch functionality without the need for additional hardware, while allowing for precise brightness and color measurement to correct for OLED aging.
Implementation Method 1
the display pixels emits light radiation and the photosensors capture light radiation from the display pixels reflected by the surface within a scan angle
Implementation Method 2
At the transition cover plate/air, approximately 4% is reflected back, and in the case of a finger placed on the cover plate, far less than 1% is reflected back
Data Source
AI summary
In a method for optically capturing a fingerprint or an object on a surface (2) of a cover plate (1) of a screen with a plurality of photosensors (4) which are each assigned to a respective display pixel (6), the display pixels (6) emit light radiation and the photosensors (4) capture light radiation from the display pixels (6) reflected by the surface (2) within a scan angle (8). The scan angle (8) describes in a virtual mirror image plane (9) the size of the display pixel (6).