Touch Sensor Fingerprint Integration Uniform Brightness
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Solution Overview
Problem
Existing fingerprint sensors integrated with touch sensors on displays face challenges in achieving uniform brightness due to differences in light transmittance between single-layer touch sensors and multi-layer transparent electrode structures, leading to darkened areas where the fingerprint sensor is applied.
Innovation Solution
A touch sensor design with a fingerprint sensor that includes a lower electrode layer with first and second touch sensor electrodes, dummy electrodes, and fingerprint sensor electrodes, where the fingerprint sensor electrodes are positioned to face each other, and the dummy electrodes are used to maintain uniform light transmittance, ensuring the touch sensor and fingerprint sensor have similar light transmittance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-layer transparent electrode structure is used for the fingerprint sensor, then the fingerprint sensing performance is improved, but the light transmittance is reduced causing darkened areas on the display
Solution Approach 1:
The patent applies local quality by using a single-layer transparent electrode structure specifically for the fingerprint sensor region, while other regions use different structures. This localized approach allows the fingerprint sensor area to have optimized light transmittance matching the surrounding display area, preventing darkened spots while maintaining fingerprint sensing capability.
Solution Approach 2:
The patent changes the structural parameter of the transparent electrode from multi-layer to single-layer configuration. This parameter change reduces the overall thickness and material density of the electrode structure, thereby increasing light transmittance and eliminating the darkened appearance in the fingerprint sensor region while preserving adequate sensing performance.
2Ease of manufacture
If a single-layer electrode structure is used for the touch sensor, then the manufacturing process is simplified, but the light transmittance cannot be uniformly matched with multi-layer fingerprint sensor structures
Solution Approach 1:
The patent implements local quality by configuring the electrode structure differently for the fingerprint sensor region compared to other touch sensor regions. The fingerprint sensor area uses a single-layer structure to match light transmittance, while other areas may use different configurations, achieving uniform overall appearance without complicating the entire manufacturing process.
3Illumination intensity
If transparent electrodes with high transmittance are used, then the display brightness is improved, but the electrical conductivity is reduced making high frequency operation difficult
Solution Approach 1:
The patent changes the electrode structure parameter from multi-layer to single-layer, which improves light transmittance. The single-layer configuration with optimized material properties achieves the necessary electrical conductivity for high-frequency operation while providing superior optical transparency compared to multi-layer structures.
Solution Approach 2:
The patent employs composite material strategies by selecting transparent electrode materials with optimized properties that balance both electrical conductivity and optical transmittance. The single-layer structure uses materials engineered to provide adequate conductivity for fingerprint sensing operations while maximizing light transmission for display brightness.
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 design ensures uniform brightness across the display device by maintaining consistent light transmittance between touch sensors and fingerprint sensors, eliminating darkened areas and enhancing display output.
Implementation Method 1
The fingerprint sensor has generally used a capacitance manner, which may be mainly divided into a unit cell driving manner and a matrix driving manner
Data Source
AI summary
The present invention is to provide a touch sensor with a fingerprint sensor capable of making brightness uniform by removing a difference in brightness in a portion to which a touch sensor and the fingerprint sensor are applied, in which an output of a touch display device of uniform brightness may be obtained by applying dummy electrodes to a portion constituting the touch sensor to change a structure so that light transmittances of the fingerprint sensor and the touch sensor are the same as or similar to each other or controlling a portion at which the finger sensor is positioned in an entire region of a light emitting layer to be brighter than the rest portion by a control unit of touch display devices to which the fingerprint sensor according to various embodiments of the present invention is applied.