Photoelectric Fingerprint Sensor Layout for Liveness Detection
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Solution Overview
Problem
Existing photoelectric fingerprint identification systems face technical contradictions between fingerprint identification and living body detection, requiring separate sensors and occupying significant space and incurring high costs due to the use of infrared filters that interfere with infrared-based living body detection.
Innovation Solution
A photoelectric fingerprint identification apparatus with a photosensitive fingerprint sensor partitioned into non-overlapping first and second sensing regions, where the first region is covered with an infrared filter for fingerprint capture and the second region is not, allowing simultaneous fingerprint identification and living body detection using visible and infrared light signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an infrared filter is designed above the fingerprint sensor to filter out red light and infrared for fingerprint identification, then fingerprint identification quality is improved, but infrared-based living body detection is interfered with
Solution Approach 1:
The sensor is divided into two distinct sensing regions: a first sensing region covered by an infrared filter for fingerprint identification, and a second sensing region without the infrared filter for living body detection. This segmentation allows each region to perform its specific function without interference from the other, resolving the contradiction between fingerprint identification quality and living body detection capability.
Solution Approach 2:
Different regions of the sensor are assigned different optical properties: the first sensing region has an infrared filter applied to optimize fingerprint capture, while the second sensing region lacks the filter to enable infrared transmission for living body detection. This local differentiation of optical characteristics allows simultaneous optimization for both functions.
2Measurement precision
If separate sensors are disposed for photoelectric fingerprint design and living body detection, then detection accuracy is improved, but device complexity and space occupation increase
Solution Approach 1:
The patent combines fingerprint identification and living body detection functions into a single sensor device with multiple sensing regions. This merging eliminates the need for separate sensors, reducing device complexity and space occupation while maintaining detection accuracy through the specialized first and second sensing regions.
Solution Approach 2:
The single sensor is designed to perform multiple functions: the first sensing region handles fingerprint identification while the second sensing region handles living body detection. This multi-functionality allows one sensor to replace what would traditionally require separate sensors, simplifying the overall device architecture.
3Measurement precision
If separate sensors are disposed for photoelectric fingerprint design and living body detection, then detection accuracy is improved, but manufacturing cost increases
Solution Approach 1:
By merging fingerprint identification and living body detection into a single sensor with differentiated sensing regions, the patent reduces the total number of components required. This consolidation lowers manufacturing costs while maintaining the detection accuracy needed for both functions through the specialized first and second sensing regions.
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 approach enhances anti-counterfeit capabilities, reduces hardware costs, and minimizes structural space by enabling both fingerprint and living body detection without interference, using a single sensor.
Implementation Method 1
the first sensing region is covered with an infrared filter, where reflected light of the first light signal generated by the light-emitting unit is able to reach the first sensing region
Implementation Method 2
obtain a fingerprint image by using a fingerprint sensor to sense, receive and process light signals emitted by a light source that are reflected by the pattern of lines of a finger
Implementation Method 3
the light-emitting unit generates at least a first light signal and a second light signal, the first light signal includes visible light that has a shorter wavelength than red light, and the second light signal includes red light or infrared
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A photoelectric fingerprint identification apparatus, a terminal, and a fingerprint identification method are provided. The apparatus includes: a light-emitting unit (6, 7), where the light-emitting unit (6, 7) generates at least a first light signal and a second light signal; a photosensitive fingerprint sensor (1), where the photosensitive fingerprint sensor (1) includes a first sensing region (11) and a second sensing region (12) that do not overlap each other, and the first sensing region (11) is covered with an infrared filter (3); an image detection unit, configured to detect reflected light energy of the first sensing region (11) to obtain fingerprint information; and a living body detection unit, configured to detect reflected light energy of the second sensing region (12) to obtain living body detection information.