Optical Pattern Layer for Fingerprint Sensing

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Solution Overview

Problem

Current display devices face challenges in achieving high sensitivity for fingerprint recognition, particularly due to interference from light reflected at angles greater than a certain threshold, which reduces the accuracy of fingerprint recognition.

Innovation Solution

The display device incorporates an optical sensor with a light-shield section and transmission sections arranged in a specific pattern to control the incident angle of light, using organic materials for light transmission and absorption, and an etch stop layer to protect the sensing element, thereby enhancing fingerprint recognition sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an optical sensor is used to detect light reflected from the display module for fingerprint recognition, then the display device can provide fingerprint detection function, but light reflected at angles greater than a certain threshold causes interference and reduces recognition accuracy

Engineering Contradiction:

Improvefingerprint detection functionVSAvoidrecognition accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The optical pattern layer is segmented into light-shield sections and transmission sections. The transmission sections are arranged in a specific pattern to selectively transmit light within certain angle ranges while the light-shield sections block light at other angles, thereby resolving the contradiction between providing fingerprint detection function and maintaining recognition accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the optical pattern layer have different optical properties: transmission sections allow light passage while light-shield sections block light. This local differentiation of optical characteristics enables the system to accept light at specific angles while rejecting light at other angles, improving recognition accuracy without sacrificing the fingerprint detection function.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If a light-shield section and transmission sections are arranged in a specific pattern to control incident angle of light, then recognition accuracy is improved, but the device structure becomes more complex

Engineering Contradiction:

Improverecognition accuracyVSAvoidoptical pattern layer structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The optical pattern layer combines multiple functions into a single layer: it provides both the light-shielding function and the angle-selective transmission function. By merging these functions into one integrated layer rather than using separate components, the structure achieves the required complexity for angle control while minimizing overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The optical pattern layer serves multiple purposes simultaneously: it acts as a light-shielding layer, an angle-selective filter, and a structural support for the optical sensor. This multi-functionality reduces the need for additional separate components, thereby improving recognition accuracy without proportionally increasing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Illumination intensity

If transmission sections include organic material that allows light to pass through, then light transmission is achieved, but organic materials may have limitations in durability and stability

Engineering Contradiction:

Improvelight transmissionVSAvoidmaterial durability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The optical pattern layer uses composite material construction with light-shield sections and transmission sections made from different organic materials optimized for their specific functions. The transmission sections use organic materials with high light transmission properties, while the light-shield sections use organic materials with high light absorption properties. This composite approach balances light transmission requirements with material durability and stability.

Inventive Principle:

Principle #40Composite materials

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 configuration improves the accuracy of fingerprint recognition by limiting the incident angle of light to the sensing element, reducing interference and enhancing sensitivity.

Implementation Method 1

Each of the transmission sections may include a first organic material that allows the light to pass therethrough, wherein the light-shield section includes a second organic material that absorbs the light

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS11694468B2Display device and method of fabricating the same

Publication Date: 2023.07.04 SAMSUNG DISPLAY CO LTD

AI summary

Disclosed is a display device including a display module, and a sensor layer below the display module for detecting light reflected from the display module, and including a base layer, a sensing layer on the base layer and including a sensing element that detects the light, and an optical pattern layer between the sensing layer and the display module, and including a light-shield section defining openings arranged at intervals when viewed in a plan view, and transmission sections respectively located in the openings.