Light Control Layer Layout for In-Display Fingerprint Sensing

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Solution Overview

Problem

Existing display devices face challenges in controlling the viewing angle and light characteristics, particularly in vehicles, which can interfere with driving and privacy, and fingerprint sensors placed in the display area suffer from reduced light incidence and increased noise light, affecting recognition accuracy.

Innovation Solution

A display device with a light control layer comprising a light transmitting film and a light blocking film, where the light transmitting portions are designed with specific ratios and arrangements to minimize thickness and viewing angle, and a method for manufacturing this device that enhances process efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the area of the light blocking unit of collimator is reduced to increase the amount of light incident on the light sensing unit, then the amount of light incident on the light sensing unit increases, but noise light incident on the light sensing unit increases, thus fingerprint recognition accuracy is lowered

Engineering Contradiction:
Improveamount of light incident on light sensing unitVSAvoidfingerprint recognition accuracy
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The light control layer is divided into multiple light transmitting portions and light blocking portions arranged in a specific pattern. This segmentation allows the light transmitting portions to guide light to the fingerprint sensor while the light blocking portions prevent noise light from reaching the sensor, thereby resolving the contradiction between increasing light incidence and reducing noise light.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the light control layer are assigned different functions: light transmitting portions are positioned to guide light from light emitting elements to the fingerprint sensor, while light blocking portions are positioned to block noise light. This local differentiation of quality allows simultaneous optimization of light incidence and noise reduction.

Inventive Principle:
Principle #3Local quality

2Reliability

If a light control layer is formed to control viewing angle and light characteristics, then viewing angle control and light characteristics are improved, but device complexity increases

Engineering Contradiction:
Improveviewing angle controlVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The light control layer performs multiple functions simultaneously: it controls viewing angle, guides light to the fingerprint sensor, and blocks noise light. By integrating these functions into a single layer with a specific pattern, the invention reduces overall device complexity while achieving reliable viewing angle control and light characteristic optimization.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The light guiding function and noise blocking function are merged into a single light control layer structure. The light transmitting portions and light blocking portions work together in one integrated layer, eliminating the need for separate components and reducing device complexity while maintaining reliable light control.

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 solution improves light characteristics and viewing angle control, enhancing fingerprint recognition accuracy by reducing noise light and optimizing the display area.

Implementation Method 1

a light transmitting film that transmits the light

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 2

a light blocking film that blocks the light

Methodology Applied
Scientific EffectLight blocking: Absorption (EM radiation)

Implementation Method 3

improving light characteristics by forming a light control layer that simultaneously minimizes a thickness and a viewing angle

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP4351300B1Display device, method for manufacturing display device, and fingerprint sensor
Publication Date: 2026.04.15 SAMSUNG DISPLAY CO LTD
  • EP4351300B1 patent drawingFigure 1A
  • EP4351300B1 patent drawingFigure 1B
  • EP4351300B1 patent drawingFigure 2

AI summary

A display device (10) includes a substrate (SUB), a light emitting element layer (5100) disposed on the substrate (SUB) and including a plurality of light emitting areas (EA) each including a light emitting element (170) that emits light, an encapsulation layer (TFE) disposed on the light emitting element layer (S100), and a light control layer (LCL) disposed on the encapsulation layer (TFE), wherein the light control layer (LCL) includes a light transmitting film (LT) that transmits the light and a light blocking film (LS) that blocks the light, and the light transmitting film (LT) includes, a first light transmitting portion (LTA1) overlapping the light blocking film (LS) in a thickness direction (DR3) of the substrate (SUB), and a plurality of second light transmitting portions (LTA2) each surrounded by the light blocking film (LS), and a thickness (LS_H) of the light blocking film (LS) is greater than a thickness (LTA1_H) of the first light transmitting portion (LTA1).