Under-Display Fingerprint Detection with Localized Light Intensity Control
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Solution Overview
Problem
Optical fingerprint devices face challenges in achieving high fingerprint identification rates due to varying light intensity across the detection area, with edge portions receiving weaker signals, and poor contact leading to lower identification accuracy.
Innovation Solution
A fingerprint detection device and method that uses a light source to emit light signals of different intensities to the central and edge detection areas, forming patterns with varying gray scale values and color ratios to enhance signal intensity, particularly in the edge areas, thereby improving signal magnitude and identification rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If uniform light intensity is used across the fingerprint detection area, then the central portion receives sufficient light, but the edge portion receives insufficient light resulting in weaker signals
Solution Approach 1:
The patent applies local quality by dividing the fingerprint detection area into multiple regions (central area and edge area) and applying different light intensity characteristics to each region. The light source emits light with different intensities to different regions, specifically providing higher intensity to the edge area and lower intensity to the central area, thereby compensating for the optical imaging principle that causes edge portions to receive weaker signals naturally.
2Reliability
If higher light intensity is used to improve edge signal strength, then edge detection improves, but central area signal becomes too strong causing saturation
Solution Approach 1:
The system avoids saturation in the central area while enhancing the edge area by applying different light intensity levels to different regions. The light source is controlled to emit light with appropriately different intensities to different regions, ensuring the central area receives sufficient but not excessive light while the edge area receives enhanced light to compensate for optical losses.
Solution Approach 2:
The patent changes the light intensity parameter spatially by controlling the light source to emit light with different intensities to different regions of the fingerprint detection area. This parameter change allows optimization of signal strength in the edge area without causing saturation in the central area, as each region receives light intensity tailored to its specific optical characteristics.
3Device complexity
If conventional optical imaging is used, then the device structure is simple, but the fingerprint identification rate is limited due to signal strength differences
Solution Approach 1:
The patent improves fingerprint identification rate by implementing local quality through region-specific light intensity control. The light source is controlled to emit light with different intensities to different regions (central vs. edge areas), compensating for the optical imaging principle that causes edge portions to receive weaker signals. This approach enhances overall identification accuracy without significantly complicating the device structure.
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
The solution increases signal intensity in edge detection areas, reduces the difference in signal magnitude between central and edge areas, and enhances fingerprint identification rates by controlling light signal intensities and patterns to improve contact and imaging quality.
Implementation Method 1
a reflected light signal formed by a light signal, corresponding to a predetermined pattern formed in a fingerprint detection area of the display screen, being reflected by a user's finger
Data Source
AI summary
Embodiments of the present application provide a fingerprint detection device and method and an electronic device. The fingerprint detection device is disposed under a display screen of an electronic device, and includes an optical component and an optical sensor, the optical component is configured to direct or converge a fingerprint detection signal to the optical sensor, the optical sensor is configured to detect corresponding fingerprint information according to the fingerprint detection signal, the fingerprint detection signal is a reflected light signal formed by a light signal corresponding to a predetermined pattern formed in a fingerprint detection area of the display screen being reflected by a user's finger, and the predetermined pattern includes a first pattern and a second pattern; a signal intensity of a first light signal corresponding to the first pattern is smaller than a signal intensity of a second light signal corresponding to the second pattern.