Optic Fingerprint Identification Adhesive Segmentation
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Solution Overview
Problem
Fingerprint recognition technologies face challenges with capacitive fingerprint readers, as they require a thin cover plate that can be damaged by external forces, and optical fingerprint readers suffer from accuracy and sensitivity issues due to light interference from adhesives.
Innovation Solution
An optical fingerprint identification device with a light-transmitting window, adhesive, and selective light-transmitting layers is configured to enhance structural strength and positioning without blocking light, using a wrap-around adhesive to isolate sealants and prevent sensitivity reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitive fingerprint reader is used with a thin cover plate, then fingerprint recognition sensitivity is improved, but the cover plate strength deteriorates and becomes prone to cracking
Solution Approach 1:
The patent replaces the capacitive sensing system with an optical fingerprint recognition system. Instead of using capacitive electrodes that require direct contact with the finger through a thin cover plate, the system uses light-emitting units and photo sensors to detect fingerprint patterns through light reflection and transmission. This substitution allows the use of a thicker, stronger cover plate while maintaining fingerprint recognition capability.
2Strength
If a full layer of gel adhesive is used to bond the optical fingerprint reader with the cover plate, then bonding strength is improved, but light transmission is blocked and fingerprint recognition accuracy deteriorates
Solution Approach 1:
The patent segments the adhesive application into two distinct regions: a light-transmitting window area where no adhesive is applied to ensure clear light transmission for fingerprint recognition, and peripheral bonding areas where adhesive is applied to provide structural support and sealing. This segmentation resolves the contradiction by providing both strong bonding and optimal light transmission.
Solution Approach 2:
The patent applies different properties of adhesive in different locations: the light-transmitting window region has zero adhesive (or minimal adhesive with high light transmission properties) to optimize optical performance, while the peripheral regions have sufficient adhesive to ensure mechanical strength and sealing. This local differentiation of adhesive quality resolves the contradiction between bonding strength and light transmission.
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 improves the structural strength and accuracy of fingerprint recognition by ensuring the adhesive does not interfere with light transmission, maintaining sensitivity while enhancing the cover plate's durability and positioning effect.
Implementation Method 1
The light-emitting unit is disposed in the shell and configured to emit light toward a target through the light-transmitting window and the cover plate
Implementation Method 2
The photo-sensor is disposed in the shell and configured to sense the light reflected by the target
Data Source
AI summary
A fingerprint identification apparatus includes a cover plate, an optic fingerprint identification device, and an adhesive. The optic fingerprint identification device has a light-transmitting window. The adhesive is disposed between the cover plate and the optic fingerprint identification device, and a projection of the adhesive on the cover plate surrounds a projection of the light-transmitting window on the cover plate.