Display Pixel Circuit for Integrated Fingerprint Sensing
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Solution Overview
Problem
Existing display devices face challenges in integrating a light sensor with fewer transistors, which complicates the implementation of high-resolution displays.
Innovation Solution
A pixel structure is designed with integrated light-emitting and light-receiving elements, utilizing a reduced number of transistors to facilitate both light emission and sensing functions, including specific transistor configurations and a storage capacitor to control current flow and voltage changes based on light exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a light sensor is integrated into the display device, then fingerprint sensing function is added, but the number of transistors increases
Solution Approach 1:
The first transistor is designed to serve dual functions: controlling the current of the light-emitting element during display operation and reading the voltage signal from the light-receiving element during fingerprint sensing. This multi-functionality eliminates the need for a separate reading transistor, thereby adding the light sensor function without increasing the total transistor count
Solution Approach 2:
The patent combines the light-emitting element and light-receiving element into a single pixel structure, merging the display and sensing functions within the same spatial unit. The first transistor is merged with the reading function, and the storage capacitor is shared between display voltage storage and sensing voltage storage, reducing overall device complexity
2Measurement precision
If more transistors are used to implement light sensor, then sensing accuracy is improved, but display resolution is reduced
Solution Approach 1:
By designing the first transistor to perform both current control and voltage reading functions, the patent achieves sensing capability without adding transistors that would occupy additional pixel area. This maintains the display resolution while enabling accurate fingerprint sensing through the shared transistor's dual operation modes
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 approach allows for the implementation of a light sensor with fewer transistors, enabling higher resolution and efficient user authentication through fingerprint sensing without increasing the transistor count, thereby enhancing display performance.
Implementation Method 1
a light-receiving element connected between a fifth node and a second power voltage, wherein a voltage of the fifth node corresponds to a light amount applied to the light-receiving element
Data Source
AI summary
A pixel of the disclosure includes a light-emitting element, a first transistor connected between a first power voltage and the light-emitting element, and configured to control a current flowing through the light-emitting element, and a light-receiving element connected between a fifth node and a second power voltage, wherein a voltage of the fifth node corresponds to a light amount applied to the light-receiving element, and wherein a current transmitted to a readout line through the first transistor corresponds to the voltage of the fifth node.