Under-screen Optical Sensor Module for On-Screen Fingerprint Sensing
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Solution Overview
Problem
Conventional fingerprint sensors in mobile devices are bulky and require a separate footprint, conflicting with the need for a compact design and high spatial image resolution, and often rely on capacitive or optical imaging methods that necessitate a large sensor area and multiple sensing pixels, making them inefficient in terms of space and functionality.
Innovation Solution
An optical sensor module that utilizes the light emitted by a display screen, such as OLED pixels, to perform fingerprint sensing by capturing and detecting returned light from the top surface, integrating the sensor beneath the display panel to achieve high-resolution imaging without the need for additional space or separate sensing areas, allowing for on-screen fingerprint detection and other parameter measurements like live finger detection and touch force analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional fingerprint sensors are implemented separately from the display screen, then fingerprint sensing functionality is achieved, but device space is consumed and compact design is compromised
Solution Approach 1:
The patent combines the fingerprint sensor with the display screen by placing the sensor array beneath the display panel, allowing the display structure to serve dual purposes as both visual output and fingerprint sensing surface, thereby eliminating the need for separate sensor footprint
Solution Approach 2:
The display screen structure is designed to perform multiple functions simultaneously: displaying visual information and sensing fingerprint patterns, making the same physical structure universal for both display and biometric authentication purposes
2Measurement precision
If optical imaging methods are used for fingerprint sensing, then fingerprint detection is achieved, but large sensor area and multiple sensing pixels are required, reducing spatial efficiency
Solution Approach 1:
The patent transitions from planar sensor arrays to a three-dimensional optical imaging approach where light from beneath the display travels through multiple layers to form an image of the fingerprint on the sensor array, utilizing the vertical dimension to achieve high-resolution sensing with compact footprint
Solution Approach 2:
The patent introduces optical intermediaries including light guides, lenses, and transparent layers that mediate between the fingerprint contact surface and the sensor array, enabling efficient light transport and image formation while maintaining compact sensor dimensions
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 solution enables robust, compact, and efficient fingerprint sensing that integrates seamlessly with display screens, enhancing security and user experience by eliminating the need for separate sensors and optimizing space usage while providing additional sensing functionalities like live finger detection and touch force analysis.
Implementation Method 1
receive light that is emitted by at least a portion of the light emitting display pixels and is returned from the top transparent layer
Implementation Method 2
optical sensor module located below the display panel to receive light that is emitted by at least a portion of the light emitting display pixels and is returned from the top transparent layer to detect a fingerprint
Data Source
AI summary
Devices and optical sensor modules are provided for provide on-screen optical sensing of fingerprints by using a under-screen optical sensor module that captures and detects returned light that is emitted by the display screen for displaying images and that is reflected back by the top surface of the screen assembly. Optical collimators are provided in the under-screen optical sensor module to enhance the optical imaging performance.