Rear Projection Transparent Screen Light Projection Layer

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In rear projection display systems with transparent screens, the visibility of the video deteriorates due to reflected light from surfaces like floors, ceilings, or walls overlapping with the projected image, as the transparent screen allows background visibility and reflects light in a way that diminishes image clarity.

Innovation Solution

A display system for rear projection incorporating a transparent screen with a light projection layer of 0.1 μm to 30 μm thickness, where the optical axis of the video light forms an angle of 30° or more with respect to the screen's normal, and the specular reflectivity on the projection device side is 2% or less, utilizing a cholesteric liquid crystal layer or light scattering particles to direct video light perpendicular to the screen's surface, enhancing visibility by minimizing overlap with projected images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a transparent screen is used to allow background visibility, then transparency is improved, but reflected light from surfaces like floors, ceilings, or walls overlaps with the projected image, deteriorating video visibility

Engineering Contradiction:

ImprovetransparencyVSAvoidreflected light overlap

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a light projection layer with specific optical properties (refractive index difference, thickness 1-30 μm) at a specific location (between the transparent screen and projection device) to control light reflection locally. This layer has different optical characteristics from the surrounding transparent screen, enabling selective manipulation of reflected light without affecting overall transparency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The light projection layer acts as an intermediary between the transparent screen and the projection device. It mediates the interaction between projected light and the transparent screen by controlling reflection angles, preventing reflected light from overlapping with the projected image while maintaining the transparent screen's visibility function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If video light is projected from an oblique direction (30° or more from normal), then the light can be directed toward the visible side, but reflected light from the rear surface may overlap with the projected image, reducing visibility

Engineering Contradiction:

Improvelight direction controlVSAvoidreflected light overlap

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent changes optical parameters by introducing a light projection layer with specific refractive index characteristics and thickness (1-30 μm). This layer modifies the reflection angle parameter of light interacting with the transparent screen, ensuring reflected light does not overlap with the projected image while maintaining proper light direction control.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If the light projection layer thickness is increased to improve light direction control, then visibility may improve, but the transparent screen's transparency may deteriorate

Engineering Contradiction:

ImprovevisibilityVSAvoidtransparency

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent optimizes the thickness parameter of the light projection layer within a specific range (1-30 μm). This parameter control ensures the layer is thick enough to effectively direct light and improve visibility, yet thin enough to maintain the transparent screen's transparency and avoid excessive light absorption or scattering.

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 system improves video visibility by spacing the reflected light's position from the projected image, maintaining high transparency and reducing specular reflectivity, thus preventing overlap and enhancing overall image clarity.

Implementation Method 1

a light projection layer that directs video light incident from an oblique direction toward substantially the front direction of the front side

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

a specular reflectivity in a main surface of the transparent screen on the projection device side is 2% or less

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 3

the light projection layer is a cholesteric liquid crystal layer

Methodology Applied

Scientific EffectCholesteric liquid crystal reflection: Cholesteric Liquid Crystal

Data Source

PatentUS20240411217A1Display system for rear projection

Publication Date: 2024.12.12 FUJIFILM CORP

AI summary

Provided is a display system for rear projection including a transparent screen where a background is visible, in which visibility of a video can be improved. The display system for rear projection includes: a projection device that emits video light; and a transparent screen on which the video light emitted from the projection device is projected, in which the transparent screen includes a light projection layer that directs the projected video light toward a visible side, a film thickness of the light projection layer is 0.1 μm to 30 μm, an optical axis of the video light emitted from the projection device forms 30° or more with respect to a normal line of the transparent screen, and a specular reflectivity in a surface of the transparent screen on the projection device side is 2% or less.