Cavity Filter Biometric Display for Multi-Finger Capture

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current mobile devices face challenges in simultaneously capturing impressions of multiple fingers for biometric authentication without impairing the display screen's brightness or image quality, and struggle to distinguish between genuine and fake fingerprints.

Innovation Solution

The use of cavity filters, which are angle-selective and wavelength-dependent, are integrated into the device to allow for the simultaneous capture of multiple fingerprints on the entire display screen without reducing brightness, and to differentiate between genuine and fake fingerprints by utilizing the principle of total internal reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the sensor layer is arranged under the display screen to capture fingerprints, then the display screen area is preserved, but the image quality and brightness are impaired

Engineering Contradiction:

Improvedisplay screen areaVSAvoiddisplay brightness

Core Design Contradiction:

Area of stationary objectVSIllumination intensity

Solution Approach 1:

The patent segments the display structure into distinct functional layers: a transparent display layer that allows light passage and a separate sensor layer positioned beneath it. This segmentation enables the display to maintain its brightness and image quality while the sensor layer captures fingerprint impressions through the transparent display material.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If the sensor layer is arranged under the display screen, then space is saved, but the distance between finger and sensor increases reducing recording quality

Engineering Contradiction:

Improvedevice structureVSAvoidfingerprint recording quality

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the optical parameters of the display screen by using transparent or translucent display materials with specific light transmission characteristics. This parameter change allows optical sensors positioned beneath the display to detect fingerprint impressions with sufficient precision despite the increased distance, as the transparent display material permits adequate light interaction between the finger and sensor.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multiple fingers are captured simultaneously, then authentication security is improved, but the required area becomes too large

Engineering Contradiction:

Improveauthentication securityVSAvoidauthentication area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent makes the entire display screen surface serve multiple functions simultaneously: it displays visual information to the user and acts as a fingerprint capture surface for multiple fingers. This multi-functionality allows the device to perform multi-finger authentication with high security while preserving the full display area, as no separate authentication zone is required.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Device complexity

If the sensor layer is arranged under the backlight, then integration is improved, but light intensity is reduced for LED-based backlights

Engineering Contradiction:

Improvedevice integrationVSAvoidbacklight intensity

Core Design Contradiction:

Device complexityVSIllumination intensity

Solution Approach 1:

The patent introduces a transparent display layer as an intermediary between the backlight and the sensor layer. This intermediary structure allows the backlight to illuminate the display normally while also permitting light to pass through to the sensor layer for fingerprint detection, thus maintaining both display brightness and sensor functionality without direct conflict between these components.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution enables high-quality, simultaneous capture of multiple fingerprints on the entire display screen without affecting the display's brightness or image quality, while effectively distinguishing between genuine and fake fingerprints, thus enhancing security and usability.

Implementation Method 1

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

optical sensor pixels which detect light incident on the sensor pixels from direction of the placement surface

Methodology Applied

Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentUS12039801B2Device for capturing impressions of autopodia and use of same

Publication Date: 2024.07.16 DERMALOG JENETRIC GMBH

AI summary

A device for displaying information and for the contact-based, simultaneous capture of impressions of a plurality of blood-perfused skin regions of human autopodia, including: a placement surface for placing the autopodia, a display unit which is arranged below the placement surface and which has at least partially transparent display elements which are arranged in grid form and are individually controllable by a control unit, the display elements having display pixels which emit light in a direction of the placement surface. The device also includes optical sensor pixels which detect light incident on the sensor pixels. The sensor pixels may be arranged in a sensor layer arranged under the display unit viewed from direction of the contacting skin region or may be arranged in the display unit between the display elements. A cavity filter for angle selection is arranged in front of the optical sensor pixels.