Under-Display Camera Protective Layer for Low-Haze Light Transmission

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Solution Overview

Problem

Existing electronic devices face challenges in achieving a wider display area with a narrower non-display area, which affects the optical performance and camera functionality.

Innovation Solution

A display device design with a first display area and a second display area having different pixel densities, incorporating a protective layer with specific optical properties and a synthetic resin film or layer to enhance light transmission and reduce haze, allowing for improved camera performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a conventional display panel design is used, then the non-display area can be reduced, but the optical clarity and camera performance deteriorate due to insufficient light transmission

Engineering Contradiction:
Improvenon-display areaVSAvoidoptical clarity
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The protective layer is designed with spatially varying optical properties: in the first display area, it maintains standard protective characteristics, while in the second display area (camera region), it is optimized for maximum light transmission with specific haze (≤4%) and wavefront control. This local differentiation allows the same layer to serve both protective and optical functions in different regions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent addresses the two-dimensional trade-off between display area expansion and optical quality by introducing a third dimension - the protective layer's optical parameter space. By controlling haze, wavefront peak-valley, and wavefront RMS values, the invention adds degrees of freedom to optimize both display area and optical clarity simultaneously.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If the display area is expanded with narrower bezels, then the overall device area is reduced, but the camera performance deteriorates due to insufficient light reaching the camera module

Engineering Contradiction:
Improvedisplay areaVSAvoidcamera performance
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The protective layer acts as an intermediary optical element between the external environment and the camera module. By carefully designing its optical properties (low haze ≤4%, controlled wavefront distortion), it mediates the transmission of light from the second display area to the camera module, ensuring that the expanded display area does not compromise camera performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If a protective layer is added to protect the display panel, then the durability is improved, but the light transmission and optical clarity deteriorate due to increased haze and wavefront distortion

Engineering Contradiction:
Improveprotective layer durabilityVSAvoidlight transmission
Core Design Contradiction:
StrengthVSIllumination intensity

Solution Approach 1:

The invention changes the optical parameters of the protective layer by precisely controlling its haze value (≤4%), wavefront peak-valley value (0.05-2.00), and wavefront RMS value (0.01-0.40). These parameter specifications ensure that the protective layer maintains its protective function while minimizing its impact on light transmission and optical clarity.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If different pixel densities are used in different display areas, then the display flexibility is improved, but the manufacturing complexity increases due to additional layer structures

Engineering Contradiction:
Improvedisplay area flexibilityVSAvoidlayer structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The protective layer serves multiple functions simultaneously: it protects the display panel, controls optical properties in the camera region, and enables the dual pixel density display structure. By making the protective layer multi-functional, the invention avoids adding separate components for each function, thereby managing complexity while achieving versatility.

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

The design achieves a wider display area with a narrower bezel while maintaining high optical clarity and camera performance, with a modulation transfer function value of about 60% or more at 110 LP/mm.

Implementation Method 1

a protective layer under the display panel... a portion of the protective layer, which corresponds to the second display area, may have a haze of about 4% or less, a wavefront peak valley value of about 0.05 or more and about 2.00 or less, a wavefront root mean square value of about 0.01 or more and about 0.40 or less

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 2

a portion of the protective layer, which corresponds to the second display area, may have a haze of about 4% or less

Methodology Applied
Scientific EffectHaze reduction: Scattering

Implementation Method 3

incorporating a protective layer with specific optical properties and a synthetic resin film or layer to enhance light transmission and reduce haze

Methodology Applied
Scientific EffectLight scattering reduction: Scattering

Data Source

PatentEP4040520B1Display device and electronic device having the same
Publication Date: 2025.11.19 SAMSUNG DISPLAY CO LTD
  • EP4040520B1 patent drawingFigure 1
  • EP4040520B1 patent drawingFigure 2
  • EP4040520B1 patent drawingFigure 3

AI summary

A display device (ED) includes: a window (WM); a display panel (DP) comprising a first display area (DP-A1) and a second display area (DP-A2) having a pixel density less than that of the first display area (DP-A1), the display panel (DP) being under the window (WM); a protective layer (PPL) under the display panel (DP); and a lower layer (LM) in which a first opening (OP1) corresponding to the second display area (DP-A2) is defined and which is under the protective layer (PPL), wherein a portion of the protective layer (PPL), which corresponds to the second display area (DP-A2), has a haze of 4% or less, a wavefront peak valley value of 0.05 or more and 2.00 or less, a wavefront root mean square value of 0.01 or more and 0.40 or less.