Backlight Pinhole Collimation for Biometric Verification

Solution Overview

Problem

Current biometric verification devices with backlight fingerprint recognition require a collimation film to limit light emission angles, increasing costs and device thickness.

Innovation Solution

The use of a collimation structure with pinholes on the backlight module, where the horizontal projections of the pinholes do not overlap with the photodetector, replaces the conventional collimation film, reducing fabrication processes and device thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a collimation film is attached to limit light emission angle, then light control precision is improved, but device thickness increases and manufacturing complexity increases

Engineering Contradiction:

Improvelight control precisionVSAvoiddevice thickness

Core Design Contradiction:

Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The patent extracts the collimation function from a separate film component and integrates it directly into the backlight module structure through patterned reflective layers. This eliminates the need for an additional collimation film layer, reducing overall device thickness while maintaining light control precision through the integrated pinhole pattern design.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The collimation function is merged with the backlight module by incorporating patterned reflective layers directly into the backlight structure. The reflective layers with pinhole patterns perform both light reflection and collimation functions simultaneously, eliminating the need for separate collimation films and reducing manufacturing steps.

Inventive Principle:

Principle #5Merging (Combining)

2Manufacturing precision

If a collimation film is attached to limit light emission angle, then light control precision is improved, but device complexity increases

Engineering Contradiction:

Improvelight control precisionVSAvoidfabrication process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The collimation function is merged with the backlight module by incorporating patterned reflective layers directly into the backlight structure. The reflective layers with pinhole patterns perform both light reflection and collimation functions simultaneously, eliminating the need for separate collimation films and reducing manufacturing steps.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patterned reflective layers in the backlight module serve multiple functions: they reflect light upward, create pinhole patterns for collimation, and define the light emission angle. This multi-functionality reduces the need for separate components and simplifies the overall device structure and fabrication process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Manufacturing precision

If a collimation film is attached to limit light emission angle, then light control precision is improved, but manufacturing cost increases

Engineering Contradiction:

Improvelight control precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The collimation function is merged with the backlight module by incorporating patterned reflective layers directly into the backlight structure. The reflective layers with pinhole patterns perform both light reflection and collimation functions simultaneously, eliminating the need for separate collimation films and reducing manufacturing steps.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patterned reflective layers in the backlight module serve multiple functions: they reflect light upward, create pinhole patterns for collimation, and define the light emission angle. This multi-functionality reduces the need for separate components and simplifies the overall device structure and fabrication process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 decreases the number of fabrication processes and reduces the device thickness while maintaining effective light control for clear fingerprint imaging without the need for a collimation film.

Implementation Method 1

the range of the light emission angle has to be limited to decrease the angle of the light being reflected from the finger to the detector and prevent the detector from receiving too much large-angle stray light

Methodology Applied

Scientific EffectLight: Light

Data Source

PatentUS11694466B2Biometric verification device

Publication Date: 2023.07.04 AU OPTRONICS CORP

AI summary

A biometric verification device includes a backlight module, a photodetector, a switching element, and at least one collimation structure. The photodetector is disposed on the backlight module. The switching element is disposed on the backlight module and electrically connected with the photodetector. The at least one collimation structure is disposed on the backlight module and has a first pinhole and a second pinhole. The horizontal projections of the first pinhole and the second pinhole on the backlight module do not overlap with the horizontal projection of the photodetector on the backlight module.