Under-Display Fingerprint Sensor Aperture Light Shielding
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Solution Overview
Problem
Fingerprint sensors disposed beneath displays in electronic devices face challenges with light noise from the display panel, which degrades the fingerprint recognition ratio due to scattered light interfering with the image sensor.
Innovation Solution
The electronic device incorporates a first aperture between the image lens and the image sensor to block light components scattered from the display panel, and a relay lens to collect and re-form the image, while a second aperture between the relay lens and the image sensor further blocks scattered light, improving the signal-to-noise ratio for fingerprint recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the fingerprint sensor is disposed beneath the display panel, then the fingerprint authentication function is integrated into the device, but light scattered from the display panel enters the image sensor and degrades the fingerprint recognition ratio
Solution Approach 1:
The patent introduces a light shield structure positioned between the display panel and the image sensor to block scattered light. This intermediary component prevents the harmful light from reaching the sensor while allowing the necessary optical path for fingerprint recognition to function, thereby resolving the contradiction between integration and recognition accuracy.
Solution Approach 2:
The patent extracts and removes the scattered light component from the optical path by using a light shield that selectively blocks light from the display panel. By taking out the harmful light element while preserving the useful light for fingerprint sensing, the system maintains integration benefits while improving recognition accuracy.
2Shape
If the home button is disposed on the exterior of the device, then the device exterior can be configured, but it restricts the design of full front screen devices where no space exists for the home button
Solution Approach 1:
The patent merges the home button functionality with the fingerprint sensor by positioning the fingerprint sensor beneath the display panel at the location where the home button would traditionally be. This combination allows the device to maintain a full front screen design while preserving the essential functions of both the home button and fingerprint authentication.
Solution Approach 2:
The patent implements multi-functionality by making the fingerprint sensor serve dual purposes: it provides fingerprint authentication capability while also occupying the space traditionally reserved for the home button. This universal approach allows the same structural region to fulfill multiple functions, enabling full front screen design.
3Device complexity
If light from the display panel is allowed to reach the image sensor, then the optical path is simple, but the scattered light creates noise that degrades the signal to noise ratio
Solution Approach 1:
The light shield acts as an intermediary element in the optical path that selectively blocks scattered light from the display panel while allowing the necessary light for fingerprint recognition to pass through. This adds minimal complexity to the optical path structure while significantly improving the signal to noise ratio and overall system reliability.
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 configuration effectively reduces internal optical noise, enhancing the fingerprint recognition ratio by structurally blocking scattered light from the display panel, resulting in improved accuracy and reliability of fingerprint authentication.
Implementation Method 1
light scattered through the display panel may be directed together to an image sensor
Implementation Method 2
a first aperture positioned on a first surface between the image lens and the image sensor to block a light component scattered on the display panel
Implementation Method 3
a relay lens positioned between the first surface and the image sensor to collect light having passed through the first aperture to the image sensor
Implementation Method 4
a second aperture positioned on a second surface between the relay lens and the image sensor to block a light component scattered on the display panel
Implementation Method 5
an image sensor configured to convert an image into an electrical signal
Data Source
AI summary
An electronic device is provided. The electronic device includes a display panel, an image lens positioned under the display panel to form a fingerprint image by using light reflected from user fingerprints, an image sensor configured to convert an image into an electrical signal, a first aperture positioned on a first surface between the image lens and the image sensor to block a light component scattered on the display panel, a relay lens positioned between the first surface and the image sensor to collect light having passed through the first aperture to the image sensor, and a second aperture positioned on a second surface between the relay lens and the image sensor to block a light component scattered on the display panel.