Ultrasonic Sensor Biometric Sensing in Display Active Area
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices face challenges in enhancing biometric data sensing performance in the active area without affecting display driving or reducing accuracy, particularly when optical sensors are used in bezel areas or within the active area.
Innovation Solution
An ultrasonic sensor with a pixel array, comprising scan lines, sensing lines, and sensing pixels, where a piezoelectric material is used between first and second electrodes, allowing for simultaneous driving and sensing, and optimizing voltage supply periods to improve sensing efficiency and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an optical sensor is disposed in a bezel area of the display panel, then biometric sensing function is provided, but the active area is reduced
Solution Approach 1:
The patent transitions from optical sensing (2D surface detection) to ultrasonic sensing (3D depth detection), enabling biometric authentication to occur in the depth dimension rather than requiring additional lateral space in the bezel area
Solution Approach 2:
The patent replaces the optical sensing system with an ultrasonic sensing system that uses acoustic waves and piezoelectric materials, substituting one physical mechanism for another to achieve the same biometric sensing function without occupying bezel space
2Adaptability or versatility
If an optical sensor is disposed in the active area, then biometric sensing function is provided, but display driving is affected and sensing accuracy is reduced
Solution Approach 1:
The patent replaces optical sensors with ultrasonic sensors that use acoustic wave propagation and reflection, eliminating interference with display pixels while improving sensing accuracy through depth information and reduced sensitivity to environmental light conditions
Solution Approach 2:
The patent changes the sensing parameter from optical reflection (affected by display emissions and ambient light) to ultrasonic wave reflection time and intensity, which provides more accurate and stable biometric data without being influenced by display driving states
3Measurement precision
If a piezoelectric material is used in the ultrasonic sensor, then sensing accuracy is improved, but sensor deterioration occurs over time
Solution Approach 1:
The patent employs periodic application of driving voltages to the piezoelectric material with optimized pulse widths and intervals, allowing the material to recover between activations and reducing cumulative degradation while maintaining high sensing accuracy
Solution Approach 2:
The patent applies driving voltages only during necessary sensing periods rather than continuously, and uses floating periods to allow partial recovery, thereby extending the operational life of the piezoelectric material while maintaining sensing performance
4Productivity
If driving voltage is continuously supplied to improve sensing efficiency, then energy consumption increases and sensor deterioration accelerates
Solution Approach 1:
The patent uses periodic driving voltage supply with optimized pulse widths and intervals, activating the piezoelectric material only during necessary sensing operations and allowing recovery periods, thereby extending operational life while maintaining sensing performance
Solution Approach 2:
The patent dynamically adjusts the driving voltage supply timing based on sensing requirements, using floating periods and optimized pulse sequences to match actual operational needs rather than continuous supply, reducing unnecessary energy consumption
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 ultrasonic sensor effectively senses biometric data in the active area of display panels with improved accuracy and efficiency, minimizing performance deterioration and maintaining display driving functionality.
Implementation Method 1
a piezoelectric material disposed on the first electrode
Implementation Method 2
a piezoelectric material disposed on the first electrode
Data Source
AI summary
An ultrasonic sensor and a display device and may drive a plurality of sensing pixels disposed in the ultrasonic sensor simultaneously to transmit an ultrasonic wave, may make a first electrode disposed in a sensing pixel to be floated at a timing receiving a reflected signal to store the signal, and then may perform a sensing sequentially. Therefore, as an accurate sensing may be possible while reducing a duration and a number of an ultrasonic wave transmitting, a sensitivity and an accuracy of a sensing may be maintained while improving a driving efficiency of the ultrasonic sensor.