OLED Display Panel Multiplexed Electrode Fingerprint Recognition
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Solution Overview
Problem
Current technologies face challenges in integrating fingerprint recognition into display screens of cell phones, particularly in AMOLED displays, as the metal electrode layer shields fingerprint information, preventing effective fingerprint recognition and affecting screen ratios.
Innovation Solution
An OLED display panel design with a common electrode layer divided into a first electrode and multiplexed electrodes, a multiplexed functional line connected to an external compensating circuit, and a fingerprint recognition chip, allowing for fingerprint signal acquisition and gray scale current compensation, enabling fingerprint recognition without compromising display functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal electrode layer is used in AMOLED display to maintain display functionality, then display performance is maintained, but fingerprint recognition capability deteriorates due to shielding of fingerprint information
Solution Approach 1:
The common electrode layer is segmented into multiple independent electrodes (first electrode and second electrode) that can be independently controlled. This segmentation allows different regions of the display to have different functions - the first electrode region maintains display functionality while the second electrode region enables fingerprint recognition, thus resolving the contradiction between display performance and fingerprint recognition capability
Solution Approach 2:
The display screen is designed to perform multiple functions simultaneously - it serves as both a display device and a fingerprint recognition device. The multiplexed electrode structure enables the same physical space to support both display operations and fingerprint signal acquisition, achieving universality and resolving the contradiction between these two functions
2Area of stationary object
If fingerprint recognition region is integrated into display screen to increase screen ratio, then screen ratio is improved, but image quality uniformity deteriorates due to differences between fingerprint recognition regions and normal display regions
Solution Approach 1:
Different regions of the display are assigned different qualities and functions. The first electrode region is optimized for display with appropriate voltage control, while the second electrode region is optimized for fingerprint recognition. This local differentiation allows each region to perform its specific function optimally while maintaining overall image quality uniformity across the display
Solution Approach 2:
The voltage parameters applied to different electrode regions are changed and optimized for their specific functions. By adjusting voltage signals independently for the first and second electrodes, the system compensates for potential image quality differences and ensures uniform display performance across both display and fingerprint recognition regions
3Area of stationary object
If multiplexed electrodes are used for both display and fingerprint recognition to increase screen ratio, then screen ratio is improved, but device complexity increases due to additional functional lines and switch units
Solution Approach 1:
The display electrode and fingerprint recognition electrode are merged into a single multiplexed electrode structure. By combining these functions into one physical layer with independent control capabilities, the system reduces the need for separate electrode structures and associated control circuits, thereby managing device complexity while maintaining high screen ratio
Solution Approach 2:
The multiplexed electrodes are controlled through periodic switching between different operational modes (display mode and fingerprint recognition mode) using switch units. This periodic action allows the same hardware structure to serve multiple functions at different time intervals, reducing overall device complexity compared to having permanently separate structures for each function
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 solution allows for effective fingerprint recognition within the display screen, enhancing screen ratios by integrating fingerprint recognition regions seamlessly into the AMOLED display panel without disrupting normal display operations.
Implementation Method 1
detect a capacitance change caused by the one of the plurality of multiplexed electrodes and a finger, and thereby generate a fingerprint signal
Implementation Method 2
the multiplexed functional line is electrically connected to the light-emitting layer and an external compensating circuit, to compensate a gray scale current of the light-emitting layer
Implementation Method 3
an OLED light-emitting diode
Data Source
AI summary
An organic light-emitting diode (OLED) display panel is provided. The OLED display panel includes a light-emitting layer having a first region and a second region; a common electrode layer including a first electrode and a plurality of multiplexed electrodes insulated from one another, wherein the first electrode is opposite to the first region and each multiplexed electrode is opposite to the second region; and a multiplexed functional line, wherein the multiplexed functional line is electrically connected to one of the plurality of multiplexed electrodes, to detect a capacitance change caused by the one of the plurality of multiplexed electrodes and a finger, and thereby generate a fingerprint signal. An increased screen ratio effect is provided.