Display Device Electrode Layout for Low-Capacitance Fingerprint Sensing
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Solution Overview
Problem
Existing display devices face issues with parasitic capacitance between the readout line of an optical sensor and other signal lines, which can affect the performance and efficiency of user authentication functions.
Innovation Solution
The display device is designed with a specific layout of connection lines and electrode patterns that minimize parasitic capacitance by overlapping certain lines and positioning electrode patterns to reduce interference, including a first electrode pattern between data and readout connection lines and a second electrode pattern with an island shape that is not connected to other electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the readout line and data line are routed close to each other to save space, then the area is reduced, but parasitic capacitance increases causing signal interference
Solution Approach 1:
A shielding electrode pattern is introduced as an intermediary element between the readout line and data line. This shielding electrode acts as a mediator that blocks electromagnetic field coupling between the two signal lines, thereby reducing parasitic capacitance while allowing the lines to maintain close routing for space efficiency.
2Manufacturing precision
If the readout line is positioned closer to data lines for compact design, then manufacturing precision requirements are reduced, but signal interference increases
Solution Approach 1:
The shielding electrode pattern serves as a protective intermediary that decouples the electromagnetic interaction between readout and data lines. This allows greater design flexibility in line positioning while maintaining signal integrity, as the shielding electrode absorbs or redirects interfering fields.
3Device complexity
If electrode patterns are connected to multiple signal lines to reduce component count, then device complexity is reduced, but parasitic capacitance increases
Solution Approach 1:
The electrode pattern is segmented into multiple isolated sections, each serving a specific function. The shielding electrode patterns are electrically isolated from signal lines to avoid creating parasitic capacitance, while still providing electromagnetic shielding. This segmentation allows the structure to reduce complexity without introducing harmful electrical coupling.
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 layout effectively reduces parasitic capacitance, enhancing the performance and efficiency of user authentication functions, such as fingerprint sensing, by minimizing signal interference.
Implementation Method 1
This layout effectively reduces parasitic capacitance, enhancing the performance and efficiency of user authentication functions
Implementation Method 2
an optical sensor including a light-receiving element, and configured to provide a sensing current generated based on an amount of light received by the light-receiving element
Data Source
AI summary
A display device includes: a light-emitting element to receive a data voltage from a data line; a light-receiving element to provide a sensing current to a readout line; a first readout connection line and a first data connection line; a second readout connection line; and a first electrode pattern. The readout line, the first readout connection line, and the second readout connection line are connected to each other at a same electrical node, and the data line and the first data connection line are connected to each other at a same electrical node. The second readout connection line overlaps with at least one of the data line or the first data connection line in a first area, and the first electrode pattern is located between at least one of the data line or the first data connection line and the second readout connection line in the first area.