Pixel Circuit Optical Fingerprint Sensing Integration
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Solution Overview
Problem
Existing image display devices face challenges in integrating a fingerprint sensing circuit with high resolution (500 PPI or higher) due to the area occupied by the pixel circuit, making it difficult to achieve both high-resolution fingerprint identification and efficient display functionality.
Innovation Solution
The pixel circuit incorporates a light-receiving element and shares a driving transistor or threshold voltage compensation transistor with the optical fingerprint sensing circuit, reducing the overall circuit area and enabling high-resolution fingerprint sensing while maintaining display functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-resolution fingerprint sensing circuit (500 PPI or higher) is integrated into the display panel, then fingerprint identification accuracy is improved, but the circuit area occupied increases
Solution Approach 1:
The patent merges the fingerprint sensing circuit and pixel circuit into a single integrated structure. The light-receiving element serves dual purposes: detecting fingerprint patterns and functioning as part of the display pixel circuit. This consolidation eliminates separate circuit areas while maintaining high-resolution fingerprint sensing capability at 500 PPI or higher.
Solution Approach 2:
The light-receiving element is designed to perform multiple functions simultaneously. It acts as both the fingerprint sensor for optical detection and as an integral component of the pixel circuit for display operations. This multi-functionality reduces the overall circuit area while preserving high-resolution fingerprint identification accuracy.
2Adaptability or versatility
If a light-receiving element is added to the pixel circuit for fingerprint sensing, then fingerprint sensing function is improved, but the number of circuit elements increases
Solution Approach 1:
The patent combines the fingerprint sensing functionality with existing pixel circuit elements. The light-receiving element is integrated into the pixel circuit structure, sharing transistors and signal lines with display functions. This merging approach adds fingerprint sensing capability without proportionally increasing the total number of circuit elements.
Solution Approach 2:
Existing circuit elements are designed to serve multiple purposes. The light-receiving element participates in both fingerprint detection and display pixel operations, while sharing control transistors and output pathways with the pixel circuit. This multi-functional design enhances versatility without linearly increasing device complexity.
3Productivity
If the driving transistor is used as a buffer to transmit output voltage, then signal transmission efficiency is improved, but the transistor's other functions may be compromised
Solution Approach 1:
The driving transistor is designed to perform multiple functions within the integrated circuit. It serves as the primary driver for the light-emitting element, acts as a buffer for signal transmission from the light-receiving element, and participates in threshold voltage compensation. This multi-functional design maintains signal transmission efficiency while preserving adaptability through shared transistor usage.
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 allows for accurate fingerprint identification with reduced circuit area, extending the lifetime of the self-light emitting element by compensating voltage based on light measurement, thus preventing luminance decrease and enhancing overall device performance.
Implementation Method 1
a light-receiving element which receives light emitted from the self-light emitting element and reflected through a fingerprint of a user and converts it into an electrical signal
Data Source
AI summary
The present disclosure relates to a pixel circuit including an optical fingerprint sensing circuit, a method for driving a pixel circuit including the optical fingerprint sensing circuit, and a display device including the pixel circuit including the optical fingerprint sensing circuit. The pixel circuit includes: a self-light emitting element which displays images by a driving current controlled by a driving transistor; and a light-receiving element which receives light emitted from the self-light emitting element and reflected through a fingerprint of a user and converts it into a photocurrent. The driving transistor functions as a buffer which transmits an output voltage of the light-receiving element to an output line of the pixel circuit.