Display Device Optical Layer Design for Light Reflection Reduction

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Solution Overview

Problem

Display devices face challenges in reducing external light reflectance while maintaining high transmittance, particularly in areas designed for both image display and external light transmission, such as in camera modules or sensor modules, where polarizing layers can degrade transmittance.

Innovation Solution

The implementation of a display device with a specific structure comprising a display panel, encapsulation structure, color filter layer, and overcoat layer, which includes a color filter and black matrix to reduce external light reflection without compromising transmittance, and a functional module on the rear surface for sensing or recognizing objects through a transmission area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a polarizing layer is added to reduce external light reflection, then reflectance is reduced, but transmittance in the transmission area is degraded

Engineering Contradiction:
Improveexternal light reflectanceVSAvoidtransmittance
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The display area is divided into a first area with first pixel units and a second area with second pixel units. The first surrounding area includes a first reflective layer to reduce external light reflection, while the second surrounding area includes a second transparent portion without the reflective layer to maintain high transmittance. This segmentation allows different regions to have different optical properties tailored to their specific functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different surrounding areas are assigned different optical qualities: the first surrounding area has high reflectivity to suppress external light interference, while the second surrounding area has high transparency to allow external light transmission. This local differentiation resolves the contradiction by applying the appropriate optical property only where needed.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If a reflective layer is added to reduce external light reflection, then reflectance is reduced, but device complexity increases

Engineering Contradiction:
Improveexternal light reflectanceVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The black matrix serves multiple functions: it defines pixel boundaries, absorbs stray light, and in the first surrounding area, it provides reflective properties to reduce external light reflection. By making the black matrix multi-functional, the patent reduces the need for additional separate reflective layers, thereby reducing device complexity while still achieving the desired reduction in external light reflectance.

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 configuration effectively reduces external light reflectance while enhancing transmittance in the transmission area, improving the display device's ability to both display images and sense external objects without sacrificing image quality or functionality.

Implementation Method 1

a color filter layer, the color filter layer overlapping the first pixel area and the second pixel area

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a black matrix, the black matrix overlapping the first surrounding area and the second surrounding area

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP3823032B1Display device
Publication Date: 2023.03.15 SAMSUNG DISPLAY CO LTD
  • EP3823032B1 patent drawingFigure 1
  • EP3823032B1 patent drawingFigure 2
  • EP3823032B1 patent drawingFigure 3~4

AI summary

According to one embodiment, a display device includes a display panel having a first area and a second area, the first area including a first pixel area and a first surrounding area surrounding the first pixel area, and the second area including a second pixel area, a transmission area, and a second surrounding area surrounding the second pixel area and the transmission area, an encapsulation structure on the display panel and including at least one inorganic layer and at least one organic layer, a color filter on the encapsulation structure and overlapping the first pixel area and the second pixel area, a black matrix on the encapsulation structure and overlapping the first surrounding area and the second surrounding area, and a functional module on a rear surface of the display panel and overlapping the second area.