Optical Sensor Sub-Region Segmentation for Fingerprint Sensing
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Solution Overview
Problem
Current terminal devices, such as mobile phones, face challenges in improving fingerprint sensing performance due to variations in ambient illumination and exposure settings, leading to oversaturated or underexposed signals which affect accuracy in fingerprint identification.
Innovation Solution
The implementation of multiple optical sensors arranged in sub-regions with adjustable optical parameters, where a processor controls the sensors to detect target objects with initial and adjusted parameter values to achieve optimal sensing signals within a target range, optimizing exposure time and luminous intensity for improved fingerprint identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single optical parameter is used for the entire sensing region, then the device structure is simple, but the sensing accuracy deteriorates due to ambient illumination variations across different regions
Solution Approach 1:
The sensing region is divided into multiple sub-regions, each with independently adjustable optical parameters. This segmentation allows each sub-region to be optimized for its specific ambient illumination conditions, thereby improving overall sensing accuracy without requiring a completely complex system redesign.
Solution Approach 2:
Different optical parameters are assigned to different sub-regions based on their local illumination characteristics. This local quality approach ensures that each region receives the optimal optical parameters for its specific conditions, resolving the contradiction between uniform simplicity and localized precision.
2Illumination intensity
If the exposure time is increased to capture more light in low illumination conditions, then the signal strength improves, but the signal becomes oversaturated in high illumination conditions
Solution Approach 1:
The optical parameters, particularly exposure time, are made dynamic and adjustable based on the detected ambient illumination levels. The system automatically adapts the exposure time for each sub-region according to its lighting conditions, preventing both underexposure in low light and oversaturation in bright conditions, thus maintaining consistent signal quality.
Solution Approach 2:
The system changes the exposure time parameter dynamically based on illumination conditions. By adjusting this critical parameter according to ambient light levels, the system resolves the contradiction between needing strong signals in low light and avoiding saturation in bright light.
3Ease of manufacture
If the optical sensors are arranged in a uniform grid pattern, then the manufacturing is simple, but the sensing performance varies across different regions due to ambient illumination differences
Solution Approach 1:
While maintaining a regular grid arrangement for ease of manufacture, the system segments the sensor array into multiple sub-regions that can be independently configured with different optical parameters. This allows the physical layout to remain simple while the functional characteristics are optimized for each region.
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 the consistency and accuracy of fingerprint identification by ensuring that sensing signals are within the optimal range, reducing the likelihood of oversaturation or underexposure, thereby improving the signal-to-noise ratio and overall sensing performance.
Implementation Method 1
multiple optical sensors arranged in multiple sub-regions... control the optical sensor in each sub-region to, upon detecting a target object, sense the target object
Data Source
Figure 1~2A
Figure 2B~3
Figure 4
AI summary
A terminal device (1), a sensing method, and a sensing apparatus are provided. The terminal device (1) includes a plurality of optical sensors (11), wherein the plurality of optical sensors (11) are arranged in a plurality of sub-regions, and each of the plurality of sub-regions has a respective optical parameter; and a processor, configured to: control (S21) the optical sensor (11) in each sub-region to, upon detecting a target object, sense the target object with a first optical parameter value and obtain a first sensing signal in each sub-region; determine (S22) a target signal range according to the first sensing signal in each sub-region; determine (S23) a second optical parameter value with respect to each sub-region according to the first sensing signal in the sub-region and the target signal range; and set (S24) a value of the optical parameter of each sub-region to be the second optical parameter value. Therefore, a sensing performance is improved.