Display Device Photo Sensor With Capacitive Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices face challenges in enhancing the performance of photo sensors for user authentication functions, particularly in reducing leakage currents and improving sensing sensitivity.
Innovation Solution
The display device incorporates a photo sensor with a dual-gate transistor configuration and capacitors connected between sensor transistors and a constant voltage wire, minimizing leakage currents and enhancing sensing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional photo sensor configuration is used, then the device structure is simple, but the leakage current is high and sensing sensitivity is poor
Solution Approach 1:
The sensor transistor is divided into two separate transistors: a first sensor transistor for controlling current to the readout line and a second sensor transistor for sensing. This segmentation allows each transistor to be optimized for its specific function, reducing leakage current while maintaining sensing sensitivity.
Solution Approach 2:
A capacitor is introduced as an intermediary element connected between the first and second sensor transistors. This capacitor stores charge and stabilizes the voltage between the transistors, reducing leakage current and improving the overall performance of the photo sensor.
2Measurement precision
If the photo sensor uses a dual-gate transistor configuration with capacitors, then leakage current is reduced and sensing sensitivity is improved, but the device complexity increases
Solution Approach 1:
The sensing function is segmented into two separate transistors with distinct roles. The first sensor transistor handles current control to the readout line, while the second sensor transistor dedicated to sensing. This segmentation enables optimized performance for each function, improving sensing sensitivity.
Solution Approach 2:
A capacitor is positioned as an intermediary between the two sensor transistors, storing charge and stabilizing voltage. This intermediary element reduces leakage current and enhances the precision of the sensing measurement.
3Reliability
If a single transistor is used for both current control and sensing, then the device structure is simple, but leakage current affects sensing accuracy
Solution Approach 1:
The transistor functionality is segmented into two separate transistors. The first sensor transistor is dedicated to controlling current to the readout line, while the second sensor transistor is dedicated to sensing. This segmentation eliminates the interference between current control and sensing functions, improving sensing accuracy.
Solution Approach 2:
A capacitor is introduced as an intermediary element between the two transistors, stabilizing the voltage and reducing leakage current. This intermediary structure ensures that the sensing function is not affected by current control operations, thereby improving sensing accuracy.
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 reduces leakage currents and improves the sensitivity of the photo sensor, enabling more effective user authentication through improved fingerprint detection.
Implementation Method 1
a photo sensor including a light-receiving element
Data Source
AI summary
Provided is an electronic device including a processor configure to provide input image data to a display device configured to display an image based on the input image data, and a power supply configured to supply power to the display device, wherein the display device includes a pixel including a light-emitting element, and a photo sensor including a light-receiving element at a same layer as the light-emitting element, and including a first sensor transistor configured to control a current flowing to a readout line in response to a voltage of one electrode of the light-receiving element, a second sensor transistor electrically connected between the first sensor transistor and the readout line, and including first and second sub-transistors connected in series, and a first capacitor between a first middle node, to which the first and second sub-transistors are connected, and a power line.