Touch Screen Fingerprint Recognition Plastic Film Cover
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Solution Overview
Problem
Conventional touch and fingerprint recognition modules in smartphones are independent and incompatible, with capacitive touch screens unable to meet the resolution requirements for fingerprint recognition, necessitating a separate, higher resolution capacitance detecting component and a thinner glass cover to enable effective fingerprint sensing.
Innovation Solution
A display device with a touch screen and a thin plastic cover plate, featuring intersecting touch electrodes and a conductive material like metal mesh and silver nanowires, allows for simultaneous touch and fingerprint recognition within a fingerprint recognition region, integrating both modules for enhanced sensitivity and reduced thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional glass cover plate with thickness of 0.4 mm to 1 mm is used, then the protective cover plate provides adequate protection, but the capacitive fingerprint sensing unit cannot implement fingerprint recognition due to excessive film layer thickness
Solution Approach 1:
The patent replaces the conventional glass cover plate with a plastic film cover plate having a thickness of 0.01 μm to 200 μm. This thin film structure reduces the total film layer thickness above the fingerprint recognition chip to less than 0.3 mm, enabling the capacitive fingerprint sensing unit to achieve effective fingerprint recognition while maintaining protective coverage.
2Reliability
If the cover plate thickness is reduced to less than 0.3 mm to enable fingerprint recognition, then capacitive sensitivity is improved, but the protective cover plate becomes too thin for adequate protection
Solution Approach 1:
The patent employs a plastic film cover plate with thickness of 0.01 μm to 200 μm, which is significantly thinner than conventional glass cover plates. This thin film structure reduces the distance between the finger and the fingerprint recognition chip, thereby improving capacitive sensitivity and enabling effective fingerprint recognition while maintaining sufficient protective coverage through the flexible film material.
3Reliability
If separate independent modules are used for touch recognition and fingerprint recognition, then each module can be optimized independently, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent integrates the fingerprint recognition function into the existing capacitive touch screen structure by disposing a fingerprint recognition chip on the substrate and forming touch electrodes that serve dual purposes. The touch electrodes in the fingerprint recognition region function both as touch sensing elements and as capacitance detecting components for fingerprint recognition, thereby merging two independent modules into one integrated structure and reducing device complexity.
Solution Approach 2:
The patent designs the touch electrodes to perform multiple functions: they serve as touch sensing electrodes for general touch recognition and simultaneously as capacitance detecting electrodes for fingerprint recognition in the fingerprint recognition region. This multi-functional design eliminates the need for separate dedicated fingerprint sensing electrodes, reducing overall system complexity while maintaining optimization for both functions.
4Reliability
If a multilayer film structure is used on the fingerprint recognition chip, then the chip is protected, but the outer surface coverage reduces sensing ability and requires through holes in the glass cover plate
Solution Approach 1:
The patent uses a thin plastic film cover plate with thickness of 0.01 μm to 200 μm, which significantly reduces the total film layer thickness above the fingerprint recognition chip to less than 0.3 mm. This thin film structure maintains adequate chip protection while minimizing the insulating effect of the film layers, thereby preserving the sensing ability of the capacitive fingerprint recognition chip without requiring through holes in the cover plate.
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
Enables effective fingerprint recognition by increasing capacitive sensitivity within the fingerprint recognition region, eliminating the need for separate modules and reducing manufacturing costs while maintaining device functionality.
Implementation Method 1
a capacitive fingerprint recognition unit is usually manufactured by disposing a fingerprint recognition chip on a substrate and then integrating a fingerprint recognition unit and combining with a touch screen and other devices
Data Source
AI summary
A device for touch and fingerprint recognition includes a touch screen and a cover plate disposed on the touch screen. The cover plate is a plastic film. The touch screen includes at least one first touch electrode disposed outside a fingerprint recognition region and at least one second touch electrode disposed in the fingerprint recognition region, and a distance between at least two adjacent second touch electrodes ranges from 5 μm to 50 μm.