Projection Screen Reflective Layer for Short-Throw Light Efficiency

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Solution Overview

Problem

In projection systems with a short distance between the projector and screen, achieving high light utilization rate, good uniformity, and low cost while maintaining high image quality is challenging due to large incidence angles and ambient light interference.

Innovation Solution

A reflective projection screen with a base layer, cylindrical lens layer, Fresnel structure, and light-absorbing layer, where the Fresnel structure features a threaded surface with reflective particles and a binder, and the cylindrical lens layer increases the horizontal viewing angle, while the light-absorbing layer enhances contrast by absorbing ambient light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a reflective projection screen is used to handle large incidence angles, then image quality is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveimage qualityVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The reflective layer is segmented into multiple functional layers: a base layer, a reflective particle layer (with particles of 0.02μm to 5μm diameter), and a light-absorbing layer. This segmentation allows each layer to perform its specific function optimally while simplifying the overall manufacturing process through modular construction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A binder material is introduced as an intermediary substance to hold the reflective particles in place on the base layer. This binder mediates between the base layer and reflective particles, enabling simple coating-based manufacturing while maintaining the structural integrity and optical performance of the reflective screen

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the distance between projector and screen is reduced to 50 cm, then installation space is saved, but incidence angle increases reducing light utilization rate

Engineering Contradiction:
Improveinstallation spaceVSAvoidlight utilization rate
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The light-absorbing layer parameters are optimized to absorb ambient light effectively while the reflective particle size parameters (0.02μm to 5μm) are selected to control the scattering angle of reflected light. These parameter changes enable the screen to maintain high light utilization rate even at short projection distances by controlling the angular distribution of reflected light

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The large incidence angle, which would normally cause light loss, is converted into a benefit through the light-absorbing layer that prevents stray light from reducing image contrast. The harmful ambient light interference is transformed into a controlled element that enhances image quality by being selectively absorbed

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of energy

If ambient light is not absorbed, then light utilization rate decreases, but adding light-absorbing layer increases manufacturing complexity

Engineering Contradiction:
Improvelight utilization rateVSAvoidmanufacturing complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The light-absorbing function is merged with the reflective layer structure by integrating the light-absorbing layer directly onto the reflective particle layer. This combination eliminates the need for separate ambient light filtering components, achieving both high light utilization rate and simple manufacturing through a unified layered structure

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 efficiency and uniformity, optimizes viewing angles, and reduces glare by scattering light within a controlled solid angle range, enhancing image contrast and reducing manufacturing complexity and costs.

Implementation Method 1

The reflective layer is configured to scatter and reflect, in a solid angle range corresponding to a particle size of the reflective particles, incident light incident from the Fresnel structure, to form reflected light

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

The reflective layer includes reflective particles and a binder bonded to the reflective particles... configured to scatter and reflect... incident light... to form reflected light

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

The cylindrical lens layer includes a plurality of cylindrical lenses each having a longitudinal axis perpendicular to a horizontal direction and scattering light from the Fresnel structure to increase a viewing angle of the projection screen in the horizontal direction

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 4

The light-absorbing layer is configured to absorb ambient light transmitted through the reflective layer

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 5

a Fresnel structure formed on a side of the base layer facing away from the viewer... incident light incident from the Fresnel structure

Methodology Applied
Scientific EffectLight refraction: Refraction

Data Source

PatentEP3550360B1Projection screen and manufacturing method therefor
Publication Date: 2022.02.23 APPOTRONICS CORP LTD
  • EP3550360B1 patent drawingFigure 1
  • EP3550360B1 patent drawingFigure 2
  • EP3550360B1 patent drawingFigure 3

AI summary

The present disclosure relates to a projection screen (10) and a manufacturing method therefor. The projection screen (10) includes a base layer (101), a cylindrical lens layer (100) formed on a side of the base layer (101) close to a viewer (30), a Fresnel structure (102) formed on a side of the base layer (101) facing away from the viewer (30), a reflective layer (103) formed on a side of the Fresnel structure (102) facing away from the base layer (101), and a light-absorbing layer (106) formed on a side of the reflective layer (103) facing away from the Fresnel structure (102). The reflective layer (103) includes reflective particles (1031) and a binder (1032) bonded to the reflective particles (1031). The reflective layer (103) is configured to scatter and reflect, in a solid angle range (F) corresponding to a particle size of the reflective particles (1031), incident light incident from the Fresnel structure (102), to form reflected light. The cylindrical lens layer (100) includes a plurality of cylindrical lenses (100a) each having an axis perpendicular to a horizontal direction, and scatters light from the Fresnel structure (102) to increase a viewing angle of the projection screen (10) in the horizontal direction. The light-absorbing layer (106) is configured to absorb ambient light transmitted through the reflective layer (103).