Display Device Pixel Circuit Light Blocking for Accurate Fingerprint Sensing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Fingerprint sensing accuracy in display devices is compromised by external light interference, and the use of separate films for light blocking increases thickness and manufacturing costs.

Innovation Solution

A display device with a pinhole array mask layer and light-blocking conductive pattern that selectively blocks light in a determined wavelength range, connected to pixel transistors to enhance emission efficiency and fingerprint sensing accuracy without additional films.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate film for selectively transmitting and blocking specific light is applied to improve fingerprint sensing accuracy, then fingerprint sensing accuracy is improved, but thickness and manufacturing cost increase

Engineering Contradiction:

Improvefingerprint sensing accuracyVSAvoidthickness

Core Design Contradiction:

Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent combines the light-blocking function with the existing pixel structure by making the light-blocking conductive pattern part of the pixel circuit layer, eliminating the need for a separate light-blocking film while maintaining fingerprint sensing accuracy

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The pixel structure is designed to serve multiple functions: displaying light and blocking light in specific wavelength ranges. The light-blocking conductive pattern is integrated into the pixel circuit, allowing pixels to function both as display elements and as selective light blockers for fingerprint sensing

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

Engineering Contradiction:

Improvefingerprint sensing accuracyVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the light-blocking function with the existing pixel circuit layer, eliminating the need for additional separate films and reducing manufacturing complexity and cost

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated pixel structure performs both display and selective light-blocking functions, reducing the total number of components and manufacturing steps required

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If light is blocked selectively in a determined wavelength range using integrated conductive patterns, then manufacturing time and cost are reduced, but light blocking effectiveness must be maintained

Engineering Contradiction:

Improvemanufacturing timeVSAvoidlight interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies light-blocking properties locally at the pixel level rather than using a uniform separate film. The light-blocking conductive pattern is positioned specifically within the pixel structure to block light in determined wavelength ranges while allowing other light to pass through for display and fingerprint sensing

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite structures combining transparent conductive materials with light-blocking conductive materials in the pixel circuit layer, creating a multi-functional material system that both conducts electricity and selectively blocks light wavelengths

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

Improves fingerprint sensing accuracy and reduces manufacturing time and cost by integrating light blocking within the display device structure, maintaining thinness.

Implementation Method 1

providing a function of selectively blocking light in a determined wavelength range to an insulation layer, a protective film, or the like included in the display device

Methodology Applied

Scientific EffectSelective light blocking: Absorption (EM radiation)

Implementation Method 2

a light emitting element disposed on the display element layer in a corresponding pixel area among the plurality of pixel areas

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 3

The light sensing array layer includes at least one optical sensor configured to sense incident light

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS12361875B2Display device

Publication Date: 2025.07.15 SAMSUNG DISPLAY CO LTD

AI summary

A display device including a light sensing array layer (LSAL), a substrate, a selective light transmission layer (SLTL), a pixel circuit layer (PCL), a display element layer (DEL), and pixels. The LSAL includes an optical sensor to sense incident light. The substrate is on the LSAL and includes a display area (DA) including pixel areas (PAs), and a non-DA adjacent to the DA. The SLTL is disposed on the substrate and includes through-holes to form a path of light onto the optical sensor, and a light-blocking conductive pattern (LBCP) between the through-holes. The PCL is disposed on the SLTL and includes a conductive layer and an insulation layer. The DEL is disposed on the PCL and emits light. Each pixel includes a pixel circuit disposed on the PCL, and a light emitting element on the DEL in a corresponding pixel area. The LBCP is electrically connected to the conductive layer.