Under Screen Sensor Assembly with Vertical Routing
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Solution Overview
Problem
Conventional fingerprint sensor devices, particularly those using linear light sensors, are vulnerable to hacking and have usability issues due to their bulkiness and form factor, making them inadequate for secure and accurate biometric authentication in mobile devices.
Innovation Solution
A sensor assembly featuring a silicon substrate with a sensor integrally formed on its surface, trenches, bond pads, and conductive traces, combined with multiple sensing technologies like capacitance, electromagnetism, and infrared, allowing for enhanced fingerprint recognition and authentication with ultra-thin packaging and direct integration under the device's screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear light sensor is used for fingerprint recognition, then the device can capture fingerprints, but the sensor is vulnerable to hacking and cannot distinguish between real and fake fingerprints
Solution Approach 1:
The patent combines multiple sensing technologies (capacitive sensing, electromagnetic sensing, and infrared sensing) into a single sensor assembly. This multi-modal approach allows the system to capture multiple characteristics of the fingerprint simultaneously, making it impossible for fake fingerprints to replicate all parameters, thus resolving the vulnerability to hacking while maintaining security accuracy
Solution Approach 2:
The sensor assembly uses a composite structure integrating different sensing elements (capacitive sensors, electromagnetic sensors, and infrared sensors) on a single substrate. This composite design enables the system to detect multiple physical properties of the fingerprint, creating a robust authentication mechanism that cannot be compromised by simple spoofing attempts
2Strength
If conventional fingerprint sensor packaging is used, then the sensor can be protected, but the packaging is bulky and requires a specially designed device cover with a window
Solution Approach 1:
The sensor assembly is designed to be nested directly beneath the display screen of the mobile device, eliminating the need for separate protective packaging and special cover designs. The sensor substrate serves as both the protective structure and the functional sensing element, allowing the sensor to be integrated into the existing device form factor without requiring additional space or structural modifications
Solution Approach 2:
The sensor assembly substrate serves multiple functions simultaneously: it provides mechanical protection for the sensing elements, acts as the mounting platform for the sensors, and enables direct integration with the display screen. This multi-functional design eliminates the need for separate protective packaging while maintaining sensor protection and enabling compact form factor
3Volume of moving object
If the sensor is integrated under the screen, then the form factor is improved and device integration is enhanced, but the electrical connections become more complex
Solution Approach 1:
The patent routes electrical connections through the thickness dimension of the sensor substrate rather than across the surface. Conductive vias are formed vertically through the substrate to connect bonding pads on the front surface to contact pads on the back surface, transforming a two-dimensional routing problem into a three-dimensional solution that simplifies the overall electrical connection architecture while enabling compact integration under the screen
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 provides robust, accurate, and user-friendly fingerprint recognition by distinguishing between real and fake fingerprints, with improved form factor and integration, enhancing security and usability in mobile devices.
Implementation Method 1
using sensory techniques such as capacitance, electromagnetism, and infrared sensing
Implementation Method 2
using sensory techniques such as capacitance, electromagnetism, and infrared sensing
Implementation Method 3
using sensory techniques such as capacitance, electromagnetism, and infrared sensing
Data Source
AI summary
A sensor assembly that includes a silicon substrate and a sensor integrally formed on or in its top surface. Bond pads are formed at the substrate top surface and electrically coupled to the sensor. A trench is formed into the top surface, extending toward but not reaching the substrate's bottom surface. Conductive first traces each extend from one of the bond pads and down into the trench. One or more holes are formed into the bottom surface of the substrate and extend toward but do not reach the top surface. The one or more holes terminate at the bottom of the trench in a manner exposing the conductive first traces. Conductive second traces each extend from one of the conductive first traces at the bottom of the trench, along a sidewall of the one or more holes, and along the bottom surface of the silicon substrate.