Retroreflective Aerial Image Display With Angled Polarizing Plates

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Solution Overview

Problem

Conventional aerial image display systems using retroreflection struggle with visibility issues due to the light source being visible at certain angles, causing discomfort to viewers.

Innovation Solution

The display device incorporates a configuration with multiple polarizing plates having different inclinations and a curved diffusion plate to effectively polarize light, reducing the visibility of the light source and enhancing the visibility of the aerial image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single polarizing plate is used to dim the light source, then the structure is simple, but the light source remains visible at certain angles causing viewer discomfort

Engineering Contradiction:
Improvestructure simplicityVSAvoidlight source visibility
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The single polarizing plate is divided into multiple polarizing plates with different inclination angles. Each plate segment handles specific light paths, collectively achieving complete light source dimming while maintaining structural organization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The polarizing plates are arranged with asymmetric inclination angles relative to the light source. This asymmetric configuration ensures that light from the light source is blocked at all viewing angles, eliminating the visibility problem that symmetric arrangements cannot solve.

Inventive Principle:
Principle #4Asymmetry

2Object-affected harmful factors

If multiple polarizing plates with different inclinations are added, then light source visibility is reduced, but device complexity increases

Engineering Contradiction:
Improvelight source visibilityVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Multiple polarizing plates with different inclinations are combined into a single integrated optical system. This merging approach achieves comprehensive light control functionality while maintaining a compact overall structure, balancing performance improvement with structural simplicity.

Inventive Principle:
Principle #5Merging (Combining)

3Volume of moving object

If polarizing plates are arranged parallel to the light source, then the structure is compact, but the light source remains visible and aerial image quality is compromised

Engineering Contradiction:
Improvedevice compactnessVSAvoidaerial image quality
Core Design Contradiction:
Volume of moving objectVSIllumination intensity

Solution Approach 1:

The polarizing plates are arranged in different angular dimensions rather than parallel alignment. This dimensional change in arrangement allows the system to maintain compactness while effectively controlling light paths to improve aerial image quality and eliminate light source visibility.

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

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 improved polarization efficiency reduces the visibility of the light source, allowing for clearer and more comfortable viewing of the aerial image without special glasses.

Implementation Method 1

a first polarizing plate arranged over the diffusion plate... The first polarizing plate includes a region inclined with respect to a main surface of the second polarizing plate

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

a retroreflecting member arranged on the second polarizing plate and having a design for generating an original image by irradiation of the light source

Methodology Applied
Scientific EffectRetroreflection: Retroreflector

Implementation Method 3

a polarizing beam splitter arranged to face the retroreflecting member

Methodology Applied
Scientific EffectPolarization beam splitting: Polarisation

Data Source

PatentEP4628974A1Display device
Publication Date: 2025.10.08 ALPS ALPINE CO LTD
  • EP4628974A1 patent drawingFigure 1~2
  • EP4628974A1 patent drawingFigure 3A~3B
  • EP4628974A1 patent drawingFigure 4A~4B

AI summary

A display device capable of displaying an aerial image by using retroreflection includes a light source, a diffusion plate arranged over the light source, a first polarizing plate arranged over the diffusion plate, a second polarizing plate arranged over the first polarizing plate, a retroreflecting member arranged on the second polarizing plate and having a design for generating an original image by irradiation of the light source, and a polarizing beam splitter arranged to face the retroreflecting member. The first polarizing plate includes a region inclined with respect to a main surface of the second polarizing plate.