Ultrasonic Sensor Pixel Transistor Configuration for Biometric Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices face challenges in maintaining an active display area while accurately sensing biometric information, as optical sensors either reduce the active area or impair display driving and sensing accuracy when placed in the bezel or inside the panel.
Innovation Solution
An ultrasonic sensor with a configuration of scan lines, sensing lines, and pixels, where transistors with different channel types are controlled by the same scan line, allowing for separate driving and sensing intervals to reduce power consumption and enhance sensing accuracy within the active display area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical sensor is disposed in the bezel area of the display panel, then biometric information sensing is enabled, but the active area of the display panel is reduced
Solution Approach 1:
The patent transitions from optical sensing (2D surface detection) to ultrasonic sensing (3D depth detection), enabling biometric sensing within the active display area without reducing it. The ultrasonic sensor operates in the depth dimension, allowing simultaneous display and sensing functions in the same spatial region.
Solution Approach 2:
The patent replaces the optical sensing system with an ultrasonic sensing system. Instead of using light to detect biometric information, the invention uses ultrasonic waves generated by piezoelectric materials, substituting optical detection with acoustic detection to eliminate the need for separate bezel sensor areas.
2Area of stationary object
If an optical sensor is disposed inside the display panel, then the active area is maintained, but display driving accuracy is affected and sensing accuracy is lowered
Solution Approach 1:
The patent divides the pixel structure into distinct functional regions: driving transistors for display control and sensing transistors for ultrasonic detection. This segmentation allows independent optimization of display driving and sensing functions, preventing interference between the two operations while maintaining high accuracy for both.
Solution Approach 2:
The patent implements periodic switching between driving mode and sensing mode within each pixel cycle. During the driving interval, display signals are applied; during the sensing interval, ultrasonic detection is performed. This temporal separation eliminates mutual interference while maintaining both functions at high accuracy levels.
3Measurement precision
If ultrasonic waves are generated continuously for sensing, then sensing accuracy is improved, but power consumption increases
Solution Approach 1:
The patent applies periodic action by switching the ultrasonic sensor between driving intervals (for display operation) and sensing intervals (for biometric detection). Ultrasonic waves are generated only during sensing intervals, not continuously, which maintains sensing accuracy while significantly reducing power consumption compared to continuous operation.
Solution Approach 2:
The patent discards the driving function temporarily during sensing intervals, allowing the same pixel structure to be recovered and used for ultrasonic sensing. This temporal multiplexing enables the system to alternate between display driving and sensing operations, optimizing both performance and power efficiency.
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 configuration enables efficient power management, reduces thin film transistor degradation, and improves sensing sensitivity by allowing ultrasonic wave generation and detection in the same area, maintaining high display area utilization and accuracy.
Implementation Method 1
a piezoelectric material disposed between the first electrode and the second electrode
Implementation Method 2
a piezoelectric material disposed between the first electrode and the second electrode
Data Source
AI summary
According to the embodiments of the present disclosure, an ultrasonic sensor, an ultrasonic sensing device, a display device, and a biometric information sensing method are provided, in which a first transistor and a second transistor disposed in respective pixels adjacent to each other are driven by a same scan line, and the first transistor controlling the application of a high voltage and the second transistor controlling sensing are configured with different channel types; therefore, a driving interval for generating ultrasonic waves is separated in time from a sensing interval for sensing reflected ultrasonic waves. Accordingly, an interval for applying the high voltage is reduced; therefore, power consumption can be reduced, and the degradation of components constituting the ultrasonic sensor can be overcome or reduced. In addition, sensing can be performed in an area in which ultrasonic waves are generated; thus, sensing sensitivity can be improved.