Projector Screen With Anisotropic Diffusion Layer

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Solution Overview

Problem

Conventional screens for projectors, especially monofocal projectors, face issues with contrast reduction, non-uniform brightness distribution, and limited viewing angles in bright indoor environments, and struggle to effectively handle 3D images due to high angles of incidence and reflection, leading to poor image quality and crosstalk.

Innovation Solution

A screen with an anisotropic base diffusion layer, a lens layer, a reflective layer, and a surface protective layer, featuring fine patterns and materials like PMMA and carbon black, which minimizes retardation value differences across angles of incidence and omits the diffusion layer to reduce crosstalk and enhance viewing angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a conventional screen is used with a monofocal projector, then the projector structure is simple, but the image quality deteriorates due to high angles of incidence causing light to reflect toward the ceiling rather than user's eyes

Engineering Contradiction:
Improveprojector structureVSAvoidimage brightness
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The screen is divided into multiple functional layers: anisotropic base diffusion layer with fine patterns, lens layer, reflective layer, and surface protective layer. Each layer performs a specific function to control light paths, enabling the screen to handle high-angle incidence from monofocal projectors while maintaining image brightness and quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The anisotropic base diffusion layer exhibits different optical properties in different directions, with specific retardation values controlled at different angles of incidence. This local optical quality control ensures that light at high angles is properly directed toward viewers while maintaining uniform brightness distribution across the screen.

Inventive Principle:
Principle #3Local quality

2Device complexity

If a conventional screen is used in bright indoor space, then the screen structure is simple, but contrast is reduced and image quality deteriorates

Engineering Contradiction:
Improvescreen structureVSAvoidimage contrast
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The screen employs composite material structure combining anisotropic base diffusion layer (PMMA film with fine patterns), lens layer (refractive index 1.4-1.7), reflective layer (aluminum or silver), and surface protective layer. This composite structure enhances contrast ratio and image quality for viewing in bright indoor environments by properly managing light reflection and diffusion.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If a conventional screen is used, then the screen is simple to manufacture, but viewing angle is limited and brightness distribution is non-uniform

Engineering Contradiction:
Improvescreen manufacturingVSAvoidviewing angle
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The anisotropic base diffusion layer introduces directional control in the optical path by utilizing birefringence properties with specific retardation values. This dimensional control of light propagation enables uniform brightness distribution across wide viewing angles while maintaining manufacturability through established film fabrication techniques.

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

4Device complexity

If a conventional screen is used for 3D projection, then the screen structure is simple, but the reflection angle deviates from 3D glasses position causing crosstalk and making 3D viewing impossible

Engineering Contradiction:
Improvescreen structureVSAvoid3D image quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The anisotropic base diffusion layer is designed with specific retardation parameters (10 nm or less at 50° incidence, or 5 nm or less difference between 0° and 50°) to precisely control the reflection angle. This parameter optimization ensures that reflected light from monofocal 3D projectors correctly reaches the viewer's eyes wearing 3D glasses, eliminating crosstalk and enabling proper 3D viewing.

Inventive Principle:
Principle #35Parameter changes

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 allows for uniform brightness distribution, improved viewing angles, and effective use in bright indoor spaces, including passive 3D projectors, by reducing light distortion and crosstalk, enabling clear and high-quality image projection.

Implementation Method 1

a base diffusion layer provided with fine patterns formed thereon

Methodology Applied
Scientific EffectLight diffusion: Scattering

Implementation Method 2

The anisotropic base diffusion layer may have small change of a retardation value according to angles of incidence of the image received from the projector

Methodology Applied
Scientific EffectAnisotropic optical properties: Anisotropy

Implementation Method 3

a lens layer formed on the rear surface of the anisotropic base diffusion layer

Methodology Applied
Scientific EffectLight refraction: Refraction

Implementation Method 4

The lens layer may be a Fresnel lens provided with a rear surface portion segmented into a plurality of surfaces

Methodology Applied
Scientific EffectFresnel lens effect: Fresnel Lens

Implementation Method 5

a reflective layer deposited on the rear surface of the lens layer

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2930561B1Screen for reflective projector
Publication Date: 2021.10.27 LG ELECTRONICS INC
  • EP2930561B1 patent drawingFigure 1
  • EP2930561B1 patent drawingFigure 2
  • EP2930561B1 patent drawingFigure 3

AI summary

A screen for a projector for displaying an image received from a projector comprises: an anisotropic base diffusion layer having a fine pattern; a lens layer formed on a rear surface of the anisotropic base diffusion layer; a reflection layer deposited on a rear surface of the lens layer; and a surface protection layer coupled with a front surface of the anisotropic base diffusion layer. The screen for a projector enables a viewer to view an image from a single focus projector inside a bright room, brightness to be uniformly distributed throughout the screen, and a viewing angle to be obtained.