Fingerprint Detection Electrode Layout for Moire Pattern Reduction
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Solution Overview
Problem
Display devices with integrated fingerprint sensors often experience unintended patterns such as moire and light reflecting patterns due to the arrangement of electrodes, which can interfere with fingerprint detection and visual recognition.
Innovation Solution
A fingerprint detection device with zigzag detection electrodes and spaced drive electrodes, including dummy electrodes in a floating state, is arranged to minimize capacitance variations and reduce the occurrence of unintended patterns by optimizing the spacing and shape of electrodes, thereby improving detection accuracy and reducing visual interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrodes are arranged in a fingerprint detection region overlapping with display region, then fingerprint detection function is enabled, but unintended patterns (moire and light reflecting patterns) are visually recognized
Solution Approach 1:
A light-shielding layer is introduced as an intermediary between the electrodes and the display region. This layer selectively blocks light from reflecting off the electrodes, preventing moire and light reflecting patterns from being visually recognized, while allowing the fingerprint detection function to operate normally through capacitance changes.
Solution Approach 2:
The light-shielding properties are applied locally only in the fingerprint detection region where electrodes are present, rather than across the entire display. This allows the display to maintain normal visual quality in non-fingerprint regions while eliminating unwanted patterns only where electrodes would cause them.
2Measurement precision
If electrodes are arranged closely to improve detection sensitivity, then detection precision is improved, but capacitance variations increase causing detection accuracy to deteriorate
Solution Approach 1:
The patent optimizes electrode parameters including spacing, width, and arrangement patterns to achieve a balance where electrodes are close enough for sensitive detection but far enough to minimize parasitic capacitance variations. This parameter optimization allows high detection sensitivity while maintaining detection 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
The solution effectively reduces the occurrence of moire and light reflecting patterns, enhancing fingerprint detection performance and visual clarity by ensuring uniform capacitance and electrode alignment, thus improving detection accuracy and user experience.
Implementation Method 1
A fingerprint sensor detects a capacitance change corresponding to a recess or protrusion of a fingerprint to detect the shape of a fingerprint
Implementation Method 2
Electrodes in a fingerprint detection region reflects light incident from the cover glass side
Data Source
AI summary
Provided are a fingerprint detection device and a display device that can reduce the occurrence of unintended patterns. The fingerprint detection device has a plurality of drive electrodes and a plurality of detection electrodes. The detection electrodes have a plurality of first line parts, a plurality of second line parts extending in a direction crossing the first line parts, and bent parts coupling the first line parts and the second line parts to each other. The drive electrodes have a plurality of electrodes arranged spaced apart from each other in a plan view, connecting parts coupling the electrodes adjacent to each other in the second direction to each other, and dummy electrodes in a floating state, each of the dummy electrodes being arranged between two electrodes arranged in the first direction between two detection electrodes.