In-Display Fingerprint Sensor Using Piezoresistive Pressure Control
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Solution Overview
Problem
Current optical fingerprint recognizers integrated on touch control boards in display terminals face limitations due to restricted non-display regions, which lowers the screen-to-body ratio and increases manufacturing costs.
Innovation Solution
A fingerprint recognizer comprising a pressure detector unit, a light emitter unit, and a light sensor unit integrated within the display region, where the pressure detector sends signals to control the light emitter to emit light signals based on pressing strength, and the light sensor converts light-reflection signals into electrical signals for fingerprint analysis, enabling fingerprint recognition directly on the display screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical fingerprint sensors are integrated on touch control boards in non-display regions, then fingerprint recognition function is achieved, but screen-to-body ratio is reduced and manufacturing cost increases
Solution Approach 1:
The patent merges the fingerprint sensor array with the display pixel array into a single integrated structure. The fingerprint sensors are positioned at the same locations as display pixels, allowing both functions to coexist in the same region without occupying additional space, thereby maintaining screen-to-body ratio while enabling fingerprint recognition.
Solution Approach 2:
The display region is made multi-functional by enabling it to serve both as display pixels and as fingerprint sensing locations. Each pixel location can function as either a display element or a fingerprint sensor depending on the operational mode, eliminating the need for separate dedicated fingerprint recognition areas.
2Reliability
If optical fingerprint sensors are integrated on touch control boards in non-display regions, then fingerprint recognition function is achieved, but manufacturing cost increases
Solution Approach 1:
The patent combines the fingerprint sensor array and display pixel array into a single integrated structure that can be manufactured as one unit. This merging eliminates the need for separate manufacturing processes and assembly steps for adding fingerprint sensors after display production, thereby reducing manufacturing complexity and cost.
Solution Approach 2:
The patent replaces traditional mechanical or separate-component fingerprint sensing methods with an optical implementation that uses the display pixels themselves as sensors. This substitution eliminates the need for additional mechanical structures, separate sensor modules, and complex integration processes, simplifying manufacturing.
3Reliability
If fingerprint recognition is implemented using separate mechanical keys, then fingerprint recognition is achieved, but device structure becomes complex and screen-to-body ratio is reduced
Solution Approach 1:
The patent extracts the fingerprint recognition function from the mechanical key structure and relocates it to the display region. By removing the need for separate mechanical keys and integrating fingerprint sensing directly into the display pixels, the device structure is simplified while maintaining fingerprint recognition capability.
Solution Approach 2:
The patent replaces the mechanical key-based fingerprint recognition system with an optical sensing system using display pixels. This substitution eliminates mechanical moving parts, complex key structures, and associated assembly requirements, thereby reducing device complexity.
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 solution enhances fingerprint recognition reliability by utilizing the display region for fingerprint data collection, improving user habit data acquisition and reducing manufacturing costs by eliminating the need for mechanical keys.
Implementation Method 1
the light emitter unit is configured to emit a light signal under control of the signal
Implementation Method 2
receive a light-reflection signal formed by the light signal reflected by the finger
Implementation Method 3
to convert the light-reflection signal into an electrical signal
Implementation Method 4
the piezoresistor includes a first electrode, a second electrode and a pressure sensitive material between the first electrode and the second electrode
Data Source
AI summary
A fingerprint recognizer, a fingerprint recognition method, a light emitter device, an optical sensor and a display device are provided. The fingerprint recognizer includes a pressure detector unit, a light emitter unit, a light sensor unit, and a fingerprint analyzer unit. The pressure detector unit is configured to detect the strength at which a finger presses a display screen, and send a signal to the light emitter unit according to the strength. The light emitter unit is configured to emit a light signal under the control of the signal of the pressure detector unit. The light sensor unit is configured to receive a light-reflection signal formed by the light signal reflected by the finger, convert the light-reflection signal into an electrical signal and output the electrical signal to the fingerprint analyzer unit. The fingerprint analyzer unit is configured to determine fingerprint information according to the received electrical signal.