Display-Integrated Biometric Sensor Bonding With UV Resin Filling
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Solution Overview
Problem
The positioning of biometric sensing modules in electronic devices, such as fingerprint recognition sensors, is challenging due to stress-induced deformation of display panels and potential light reflection issues from unfilled gaps, which affect display quality.
Innovation Solution
A method involving the use of UV curable resins with controlled curing and pressure application to form filling layers around the sensor module, ensuring complete filling of gaps and preventing light reflection, while maintaining sensor functionality and display integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensor module is positioned on a display panel, then biometric sensing function is achieved, but stress-induced deformation of the display panel occurs affecting positioning precision
Solution Approach 1:
The patent divides the bonding structure into multiple segments: a first bonding material layer and a second bonding material layer, with the sensor module positioned on the first layer and the display panel bonded through the second layer. This segmentation allows independent optimization of each bonding interface, compensating for stress-induced deformation and maintaining positioning precision.
Solution Approach 2:
The patent changes the physical and chemical parameters of the bonding materials, specifically using UV curable resins with controlled viscosity and curing characteristics. By adjusting the resin formulation and curing parameters (UV intensity, exposure time), the bonding process can accommodate panel deformation while achieving precise sensor positioning.
2Reliability
If gaps are left around the sensor module for accessibility, then sensor functionality is maintained, but light reflection from unfilled gaps degrades display quality
Solution Approach 1:
The patent applies different bonding materials with different properties to different regions: the first bonding material layer provides gap-filling and light-blocking properties around the sensor module periphery, while the second bonding material layer provides structural bonding. This local differentiation eliminates light reflection from gaps while preserving sensor functionality.
Solution Approach 2:
The bonding material acts as an intermediary substance that fills the gaps between the sensor module and display panel. This intermediary layer serves dual functions: maintaining the necessary spacing for sensor operation while simultaneously blocking light paths that would cause reflection, thus mediating between the conflicting requirements.
3Productivity
If high intensity UV ray is used to cure the resin quickly, then curing speed is improved, but the resin may not properly fill the gaps before curing
Solution Approach 1:
The patent applies preliminary action by first positioning the sensor module on the uncured resin, then using a pressing member to force the resin into gaps and voids before UV curing initiates. This preliminary mechanical filling ensures complete gap penetration, after which the UV curing process rapidly solidifies the resin in its filled position, achieving both complete filling and high productivity.
Solution Approach 2:
The patent employs periodic action by separating the curing process into distinct phases: first, a low-intensity or delayed UV exposure that allows resin flow and gap filling; second, a high-intensity UV exposure that completes the curing process. This periodic application of curing energy ensures both complete gap filling and rapid final curing.
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 method effectively secures the sensor module and enhances display quality by eliminating gaps and reflections, ensuring stable operation and high-frequency ultrasonic wave transmission for biometric sensing.
Implementation Method 1
UV curable resins with controlled curing
Implementation Method 2
an ultrasonic sensing method, which includes sensing vibrations by using a piezo-electric device
Data Source
AI summary
A method of fabricating an electronic device includes: fabricating a display module including a display panel, a protection film disposed on the display panel, and a cover panel disposed on the protection film, wherein the cover panel has an open portion partially exposing the protection film; forming a first resin on a first region of the open portion; forming a second resin on a second region; emitting a first UV ray to the first and second resins; placing a sensor module on the first resin; pressing the sensor module such that the first and second resins fill the first and second regions and a first filling layer and a second filling layer in the first region and the second region, respectively, are formed; and emitting a second UV ray to the second filling layer in the second region to cure the second filling layer.