Optical Sensor Light Filter Aperture Array for Fingerprint Detection

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Solution Overview

Problem

Conventional capacitive fingerprint sensors face challenges in detecting fine ridge and valley features through thick layers, such as the cover glass in mobile devices, requiring cutouts and mechanical buttons, which complicates device manufacturing and user experience.

Innovation Solution

An optical imaging device with a filter layer and substrate, featuring a light filter with an array of apertures and electrical interconnects, allows for optical sensing of biometric features like fingerprints without the need for direct contact, enabling detection through cover layers and reducing sensor size and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If capacitive sensors are used to detect fingerprints through thick cover glass, then the sensor can be integrated into mobile devices, but the sensor cannot effectively detect fine ridge and valley features through large distances

Engineering Contradiction:

Improvesensor sizeVSAvoidfingerprint detection precision

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent replaces capacitive sensing (electrical field-based) with optical sensing (light-based). The optical sensor uses light sources and photodetectors to detect fingerprint ridge and valley features through the cover glass, eliminating the distance limitation of capacitive sensors while maintaining compact form factor suitable for mobile devices.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical sensing system is divided into discrete components: light sources, optical paths, and photodetector arrays. This segmentation allows each component to be optimized independently and integrated into a compact configuration that can detect fingerprints through thick cover glass while maintaining small overall sensor volume.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If conventional optical fingerprint sensors are used, then high resolution fingerprint imaging is achieved, but the sensor becomes too bulky for mobile devices

Engineering Contradiction:

Improvefingerprint imaging resolutionVSAvoidsensor size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The optical sensor components are nested within a compact housing structure. Light sources, optical elements, and photodetectors are arranged in a layered, space-efficient configuration where smaller components are positioned within or between larger structural elements, reducing overall sensor volume while maintaining imaging resolution.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from planar 2D sensor arrangements to three-dimensional spatial configuration of optical components. By utilizing vertical stacking and angular light paths, the sensor achieves high resolution fingerprint imaging within a reduced footprint suitable for mobile device integration.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If cutouts and mechanical buttons are used to enable fingerprint sensing, then fingerprint detection is achieved, but device manufacturing is complicated and user experience is degraded

Engineering Contradiction:

Improvefingerprint detection capabilityVSAvoiddevice manufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The optical sensor system serves multiple functions: it detects fingerprints through the existing cover glass, maintains device aesthetic appearance without cutouts, and eliminates the need for separate mechanical buttons. The sensor is integrated into the display assembly, allowing the cover glass to serve both protective and sensing functions simultaneously.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the fingerprint sensor with the display assembly and cover glass structure. The optical sensing components are integrated into the existing device layers, combining the protective cover glass with the fingerprint sensing function into a unified structure that simplifies manufacturing and improves user experience.

Inventive Principle:

Principle #5Merging (Combining)

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 optical imaging device effectively captures fingerprint features with high resolution, eliminating the need for cutouts and mechanical buttons, resulting in a more compact and user-friendly design for mobile devices.

Implementation Method 1

a light filter including a blocking material forming an array of apertures

Methodology Applied

Scientific EffectLight filtering: Absorption (EM radiation)

Implementation Method 2

an optical sensor including an array of photosensors

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS10055637B2Optical sensor with substrate light filter

Publication Date: 2018.08.21 BEIJING JIIOV TECH CO LTD

AI summary

An optical biometric sensor is disclosed. The optical biometric sensor includes a filter layer having a top surface and a bottom surface. The filter layer includes a light filter including a blocking material forming an array of apertures; a substrate including an electrical interconnect comprising a set of electrical conductors. The biometric sensor further includes an optical sensor including an array of sensing elements mounted to the bottom surface of the substrate, wherein sensing elements in the array of sensing elements sensors are aligned with the array of apertures and electrically connected to the electrical interconnect.