Fingerprint Sensor Light Blocking Patterns for Display Accuracy

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Solution Overview

Problem

Existing fingerprint sensing systems in display devices face challenges in improving accuracy without compromising image quality, as increasing light intensity for better sensing can degrade image quality.

Innovation Solution

A fingerprint sensing system that employs a pinhole array layer with light blocking patterns and a bias voltage to selectively increase luminance only in specific areas, using the light emitting elements of the display device to enhance fingerprint detection accuracy without affecting the overall image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the intensity of light emitted from a light source is increased to improve fingerprint sensing accuracy, then the fingerprint sensing accuracy is increased, but the luminance of an image displayed on a display panel varies and the quality of the image may be reduced

Engineering Contradiction:
Improvefingerprint sensing accuracyVSAvoidimage luminance quality
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent divides the light blocking patterns into multiple groups (first group and second group) that can be independently controlled. By selectively activating only the first group of light blocking patterns during fingerprint sensing while keeping the second group inactive, the system segments the light emission control to improve fingerprint sensing accuracy without affecting the overall image display quality across the entire display panel.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by enabling light emission only in specific regions (where the first group of light blocking patterns is activated) during fingerprint sensing operations. This localized light emission improvement enhances fingerprint sensing accuracy in the specific sensing area while maintaining normal image display quality in the remaining display areas, thus resolving the contradiction between sensing accuracy and overall image quality.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If a bias voltage is applied to increase light emission from light emitting elements, then the quantity of light is increased for better fingerprint sensing, but this may affect the overall display performance

Engineering Contradiction:
Improvefingerprint detection accuracyVSAvoiddisplay performance
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the light blocking patterns into multiple independently controllable groups, allowing the bias voltage to be applied selectively to only the first group during fingerprint sensing operations. This segmentation enables the system to enhance light emission locally for improved fingerprint detection accuracy while maintaining normal display performance in areas controlled by the second group of light blocking patterns.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements partial action by applying the bias voltage enhancement only to a portion of the light emitting elements (those corresponding to the first group of light blocking patterns) rather than the entire display panel. This partial enhancement provides sufficient light intensity improvement for accurate fingerprint sensing while minimizing the impact on overall display performance and energy consumption.

Inventive Principle:
Principle #16Partial or excessive action

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 approach enhances fingerprint sensing accuracy while maintaining the quality of the displayed image by selectively applying a bias voltage to specific light blocking patterns, reducing the impact on image quality and improving detection precision.

Implementation Method 1

a pinhole array layer with light blocking patterns

Methodology Applied
Scientific EffectLight blocking: Absorption (EM radiation)

Implementation Method 2

increase the quantity of light emitted from light emitting elements using a change in characteristics of transistors in pixels by a bias voltage applied to a pinhole array layer

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 3

sense the fingerprint of a user using reflected light rays obtained from light emitted from the light emitting elements

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

an optical sensor array

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentEP3678053B1Fingerprint sensor and display device including the same
Publication Date: 2024.03.20 SAMSUNG DISPLAY CO LTD
  • EP3678053B1 patent drawingFigure 1~2
  • EP3678053B1 patent drawingFigure 3A~3B
  • EP3678053B1 patent drawingFigure 3C~3D

AI summary

The fingerprint sensing system may include: a light transmitting hole array layer including a plurality of light blocking patterns having a plurality of light transmitting holes to form light transmitting paths of light rays; a sensor layer including a plurality of photo sensors configured to sense light rays that pass through the light transmitting holes and are incident on the sensor layer; and metal patterns configured to apply electrical signals to pixels or the light blocking patterns. A gap between the light blocking patterns may overlap with at least some of the metal patterns.