Ultrasonic Fingerprint Sensor Power Reduction via Partial Area Scanning
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Solution Overview
Problem
The integration of fingerprint sensing into battery-operated mobile devices is hindered by high power consumption, particularly due to the need for high voltage signals, which limits the implementation of large area fingerprint sensors.
Innovation Solution
A complex sensing device comprising a touch panel, a fingerprint panel, and a sensing controller that locally scans only a part of the fingerprint panel using ultrasonic waves generated by selected pixels, reducing power consumption by limiting the areas driven by high voltage signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fingerprint sensing is performed using high voltage signals, then fingerprint sensing function is achieved, but power consumption increases
Solution Approach 1:
The fingerprint panel is divided into multiple sensing areas, and only the required sensing area is activated at any given time. The sensing controller divides the fingerprint panel into a plurality of sensing areas and controls the fingerprint circuit to sense only one sensing area at a time, segmenting the power consumption across multiple smaller regions rather than activating the entire panel simultaneously.
Solution Approach 2:
Instead of sensing the entire fingerprint panel area, the system performs partial sensing by activating only the necessary portion. The sensing controller determines the required sensing area based on touch input location and activates only that specific region, performing less than the full action would require but sufficient for the user's needs.
2Area of stationary object
If a large area fingerprint sensor is implemented, then fingerprint sensing coverage is improved, but power consumption increases
Solution Approach 1:
The large area fingerprint panel is segmented into multiple smaller sensing areas that can be independently activated. The sensing controller manages multiple sensing areas and activates only the necessary portion based on touch input, allowing the physical panel to be large while the active sensing region remains small and power-efficient.
Solution Approach 2:
The sensing area is made dynamic rather than static. The sensing controller can change which sensing area is active based on the location and nature of touch input, allowing the system to adapt the sensing region size and position in real-time to match user needs, thereby reducing power consumption while maintaining large area coverage capability.
3Measurement precision
If the entire fingerprint panel is scanned, then complete fingerprint data is obtained, but sensing time and power consumption increase
Solution Approach 1:
The fingerprint sensing process is segmented into multiple discrete sensing areas rather than scanning the entire panel as one continuous operation. The sensing controller activates and senses each sensing area separately, allowing for more efficient resource management and reduced sensing time while maintaining complete fingerprint data acquisition through systematic coverage of all segments.
Solution Approach 2:
The system performs partial sensing by activating only the necessary sensing areas based on touch input location rather than scanning the entire fingerprint panel. This partial action approach maintains sufficient fingerprint sensing accuracy for authentication while significantly reducing the time and power required compared to full-panel scanning.
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 fingerprint sensing with low power consumption, allowing for large area fingerprint sensing and flexible location-based scanning, thereby overcoming the limitations of traditional fingerprint sensing technologies.
Implementation Method 1
a transducer including a first driving electrode, a piezoelectric material layer, and a second driving electrode
Implementation Method 2
The ultrasonic waves reflected from a fingerprint after having been generated from the driving pixel can be received by the sensing pixel
Data Source
AI summary
The present disclosure relates to a display device and a sensing method, and more specifically, to a complex sensing device, a display device and a sensing method comprising: a touch panel on which a plurality of touch electrodes is disposed, a fingerprint panel on which a plurality of pixels is disposed, a touch circuit sensing the touch panel and outputting first sensing data, a fingerprint circuit sensing a fingerprint sensing area of the fingerprint panel and outputting second sensing data, and a sensing controller setting the fingerprint sensing area for enabling the fingerprint circuit to sense the fingerprint panel based on the first sensing data of the touch circuit.