LCD Display Fingerprint Sensor Integration via Capacitive Pixel Sensing

Solution Overview

Problem

The integration of fingerprint sensors into LCD displays is challenging due to hardware incompatibility, particularly the need for silicon circuits, which requires significant and costly modifications to existing LCD design and production processes.

Innovation Solution

A fingerprint sensor system that uses conductive metal lines, allowing for integration between layers of an LCD display without disrupting the visual display components, and can replace touch-screen function, utilizing existing LCD manufacturing techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing fingerprint sensing technology is integrated into LCD touch screens, then fingerprint-based authentication capability is achieved, but hardware incompatibility and costly modifications to design and production processes occur

Engineering Contradiction:

Improvefingerprint sensing capabilityVSAvoidmanufacturing process

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent extracts the fingerprint sensing function from traditional silicon-based sensor designs and implements it using the existing LCD display structure itself. The LCD pixels are repurposed to detect fingerprint ridges and valleys through capacitive sensing, eliminating the need for separate fingerprint sensor components and complex integration processes.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The LCD display serves multiple functions: visual display and fingerprint sensing. The same LCD pixels that display images also function as capacitive sensors to detect fingerprint patterns, thereby achieving multi-functionality without additional hardware components or complex integration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a separate fingerprint sensing apparatus is incorporated into computer systems, then fingerprint image capture capability is achieved, but device size and cost increase

Engineering Contradiction:

Improvefingerprint image capture capabilityVSAvoiddevice structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the fingerprint sensing function with the existing LCD display structure. By using the LCD pixels themselves for capacitive sensing, the design combines two functions (visual display and fingerprint detection) into a single integrated component, thereby reducing overall device complexity and eliminating the need for separate fingerprint sensor modules.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The LCD display serves multiple functions: visual display and fingerprint sensing. The same LCD pixels that display images also function as capacitive sensors to detect fingerprint patterns, thereby achieving multi-functionality without additional hardware components or complex integration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If silicon circuit is used for fingerprint sensing, then fingerprint sensing components can be mounted, but significant and costly modifications to LCD design and production processes are required

Engineering Contradiction:

Improvefingerprint sensing componentsVSAvoiddesign and production process

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent extracts the fingerprint sensing function from traditional silicon-based sensor designs and implements it using the existing LCD display structure itself. The LCD pixels are repurposed to detect fingerprint ridges and valleys through capacitive sensing, eliminating the need for separate fingerprint sensor components and complex integration processes.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/electrical system of separate silicon-based fingerprint sensors with an electrical field-based sensing approach using the LCD's existing pixel structure. This substitution eliminates the need for physical sensor components and their associated mounting and wiring requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 the widespread adoption of fingerprint-based authentication in devices by providing a cost-effective and minimally invasive method to integrate fingerprint sensing capability into LCD displays, enhancing security without altering the display's operation or design.

Implementation Method 1

the sensor array comprises a plurality of capacitive sensors

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS9336428B2Integrated fingerprint sensor and display

Publication Date: 2016.05.10 SYNAPTICS INC

AI summary

A fingerprint swipe sensor includes fingerprint sensor lines disposed on a surface of an LCD protective glass covered on an opposite surface with motion sensing lines. The fingerprint swipe sensor also includes a controller coupled to the fingerprint sensor lines to capture a fingerprint image when a user's finger is swiped about the fingerprint sensor lines.