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 area, conflicting with the need for a compact design while maintaining high spatial image resolution, and often rely on capacitive or optical imaging methods that are inefficient in utilizing display screen resources.
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 screen's top surface, integrating the sensor beneath the display to enhance image fidelity and reduce environmental light interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fingerprint sensors are implemented in mobile devices, then fingerprint sensing function is achieved, but device volume increases and separate sensor area is required
Solution Approach 1:
The patent combines the fingerprint sensor with the display screen by positioning the optical sensor array beneath the display panel, allowing the display structure to serve dual purposes as both visual output and fingerprint sensing platform, thereby eliminating the need for separate sensor space
Solution Approach 2:
The display screen structure is designed to perform multiple functions: it serves as both the visual display interface and the fingerprint sensing interface, with the optical sensor array utilizing the display's light emission capability for both display and fingerprint imaging purposes
2Reliability
If conventional optical imaging methods are used for fingerprint sensing, then fingerprint detection is achieved, but light utilization efficiency from display screen is low
Solution Approach 1:
The system utilizes the display screen's own emitted light to illuminate the fingerprint for sensing, eliminating the need for separate illumination sources and maximizing the utilization of light already generated by the display for its primary function
Solution Approach 2:
The optical sensor array is positioned to capture light emitted by the display screen directly, merging the display lighting function with the fingerprint illumination requirement, thereby improving light utilization efficiency
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 compact, high-resolution fingerprint sensing without the need for additional sensor space, utilizing the display screen's light for imaging and reducing background noise, thus improving user experience and device integration.
Implementation Method 1
an optical sensor array 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
Implementation Method 2
light emitting display pixels, each pixel operable to emit light for forming a portion of a display image
Implementation Method 3
receive light that is emitted by at least a portion of the light emitting display pixels and is returned from the top transparent layer
Data Source
AI summary
Devices and optical sensor modules are provided for provide on-screen optical sensing of fingerprints by using an 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. Techniques for reducing the environmental light in the optical sensing are provided.