Transparent Substrate Smart Card with Embedded Photosensor
Solution Overview
Problem
The existing manufacturing processes for smart cards with fingerprint recognition sensors are inefficient, leading to high costs, reduced yield, and potential damage to internal parts due to the need for multiple layers and complex substrate separation, which limits flexibility and durability.
Innovation Solution
A smart card design featuring a transparent substrate with a reflection layer and embedded photosensor, where light is reflected from a metal reflection layer to detect fingerprints, eliminating the need for additional passivation layers and simplifying the manufacturing process by using the transparent substrate as both a base and protective layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible substrate including polyimide is formed on a glass substrate and then separated, then the smart card achieves flexibility, but the manufacturing yield deteriorates due to the separation process
Solution Approach 1:
The invention extracts and eliminates the flexible substrate layer (polyimide) from the traditional structure. Instead of forming a flexible substrate on glass and separating it, the patent uses a transparent substrate that maintains flexibility inherently, removing the problematic separation step that reduces yield.
Solution Approach 2:
The transparent substrate serves multiple functions simultaneously: it provides the base structure, maintains flexibility, allows light transmission for fingerprint sensing, and eliminates the need for separate flexible substrate and passivation layers. This multi-functionality reduces manufacturing complexity and improves yield.
2Strength
If additional cover layers or coating layers are formed to protect the fingerprint sensor, then the sensor is protected from damage, but the material selection is limited due to transparency and flexibility requirements
Solution Approach 1:
The transparent substrate integrates multiple protective and functional roles: it serves as the base structure, provides mechanical protection, maintains flexibility, and allows light transmission. This eliminates the need for additional specialized cover layers with strict material constraints.
Solution Approach 2:
The invention merges the functions of the base substrate, protective cover layer, and flexible support into a single transparent substrate component. This consolidation removes the material selection limitations that arise from requiring multiple specialized layers.
3Ease of manufacture
If multiple manufacturing processes including substrate separation are used, then the smart card structure is achieved, but the manufacturing cost increases and yield decreases
Solution Approach 1:
The invention extracts and removes the complex substrate separation process from the manufacturing flow. By using a transparent substrate that inherently provides all necessary functions, the patent eliminates the yield-deteriorating separation step while maintaining the required card structure.
Solution Approach 2:
The transparent substrate performs multiple functions simultaneously (base structure, flexibility, light transmission, protection), which simplifies the manufacturing process by reducing the number of separate layers and processes needed, thereby improving yield and reducing cost.
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 reduces manufacturing processes and costs, improves yield, and enhances reliability by minimizing damage to internal components while maintaining flexibility and security through fingerprint recognition.
Implementation Method 1
a reflection layer separated from the transparent substrate, facing the transparent substrate, and including a metal material; a photosensor provided between the transparent substrate and the reflection layer, and sensing light reflected and input from the reflection layer
Data Source
AI summary
A smart card according to an exemplary embodiment of the present invention includes: a transparent substrate including a side contacting a finger of a user; a reflection layer separated from the transparent substrate, facing the transparent substrate, and including a metal material; a photosensor provided between the transparent substrate and the reflection layer, and sensing light reflected and input from the reflection layer; and a card substrate including an opaque material and covering the reflection layer.