Display Device With Periodic Sub-Pixel Illumination for Fingerprint Sensing
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Solution Overview
Problem
Integrating a fingerprint sensor into a display panel without compromising the display resolution and increasing the screen-to-body ratio is challenging, as conventional methods result in a small sensor area with poor sensitivity.
Innovation Solution
A display device design that includes a controlling unit, display driver, sensor driver, display element, and sensor element, where the display element comprises a group of sub-pixels turned on multiple times during a sensing period to emit light for biometric feature detection, allowing the sensor element to accumulate multiple readout signals, enhancing sensitivity without reducing pixel area or resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the fingerprint sensor is integrated into the display region, then the screen-to-body ratio is increased and borderless design is achieved, but the sensor area becomes too small resulting in poor sensitivity
Solution Approach 1:
The display driver turns on the first group of sub-pixels multiple times (3 to 120 frame times) during the sensing time period, creating periodic light emission. This allows the sensor element to receive light repeatedly and accumulate multiple readout signals, thereby improving sensitivity without increasing the physical sensor area.
Solution Approach 2:
The sensing process continues for multiple frame times (3 to 120 times) with the display element emitting light continuously throughout the sensing time period. The sensor element accumulates signals continuously, maintaining useful action throughout the entire sensing duration to maximize signal accumulation.
2Area of stationary object
If the fingerprint sensor is placed in the display region, then the display device achieves narrow-border or bezel-less design, but the resolution of the display device is compromised
Solution Approach 1:
The first group of sub-pixels serves dual functions: they act as display elements for normal operation and as light sources for the fingerprint sensor during sensing. This multi-functionality allows the sensor to be integrated into the display region without sacrificing display resolution or requiring separate sensor pixels.
Solution Approach 2:
The display driver selectively turns on the first group of sub-pixels periodically during the sensing time period to provide light for the sensor element. This periodic activation allows the same pixels used for display to serve the sensor function without interfering with normal display operation.
3Measurement precision
If the sensor element receives light from the display element multiple times, then the sensitivity is improved through signal accumulation, but the sensing time period increases
Solution Approach 1:
The display driver turns on the first group of sub-pixels in periodic intervals (3 to 120 frame times) during the sensing time period. This periodic action allows the sensor element to accumulate multiple readout signals at different time points, improving sensitivity while managing the sensing duration through controlled periodic illumination.
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 solution enables integration of biometric sensors into the display region, improving sensitivity and maintaining display quality by increasing the screen-to-body ratio and reducing timing errors.
Implementation Method 1
the display driver turns on the first group of sub-pixels one time in each of the 3 to 120 frame times
Implementation Method 2
the sensor element is capable of receiving light emitted from the display element 3 to 120 times in the sensing time period to form a plurality of readout signals
Data Source
AI summary
Disclosed is a display device including a controlling unit, a display driver electrically connected to the controlling unit, a sensor driver electrically connected to the controlling unit, a display element electrically connected to the display driver, and a sensor element electrically connected to the sensor driver. The display element comprises a first group of sub-pixels having a same color. The sensor element is sensing a biometric feature in a sensing time period, and the sensing time period comprises 3 to 120 frame times. All the first group of sub-pixels are turned on one time in each of the 3 to 120 frame times by the display driver.