3D Projection Laser Coherence Reduction via Light Modification

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Solution Overview

Problem

Conventional 3D laser projection apparatuses suffer from the generation of diffraction fringes due to the coherent nature of laser light, which affects the viewing experience and increases production and usage costs.

Innovation Solution

The 3D apparatus incorporates a light source device with a laser generation unit, a light modification element, a light guide unit, and a homogenizing unit. The light modification element, such as a scattering sheet or fly-eye lens assembly, reduces the spatial coherence of laser light and ensures a uniform and continuous angular distribution, thereby weakening the diffraction phenomenon at the prism seam of the polarizing and splitting prism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If laser light is used as a light source in 3D projection apparatus, then the brightness and coherence of the light source is improved, but diffraction fringes are generated due to the coherent nature of laser light

Engineering Contradiction:
ImprovebrightnessVSAvoiddiffraction fringes
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

A light modification element is introduced as an intermediary component between the laser light source and the projection optical system. This element modifies the coherent laser light to reduce spatial coherence while maintaining brightness, thereby eliminating diffraction fringes without sacrificing illumination intensity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The spatial coherence parameter of the laser light is changed by passing it through the light modification element. This transforms the highly coherent laser light into light with reduced spatial coherence, preventing diffraction fringe formation while preserving the high brightness characteristic of laser sources

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If conventional polarizing and splitting methods are used, then 3D projection function is achieved, but high requirements on production technology are imposed, increasing production and usage costs

Engineering Contradiction:
Improve3D projection functionVSAvoidproduction cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The light modification function is extracted as a separate element that can be independently optimized and manufactured. This allows the polarizing and splitting system to use simpler, more cost-effective components while the light modification element handles the complex coherence management

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The optical system is segmented into distinct functional modules: laser generation, light modification, and polarizing/splitting. This segmentation allows each module to be manufactured and optimized independently, reducing overall production complexity and cost

Inventive Principle:
Principle #1Segmentation

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

This configuration significantly improves the viewing effect by reducing the visibility of diffraction fringes to an unrecognizable level, thereby enhancing user experience while potentially lowering production and usage costs.

Implementation Method 1

The light modification element, such as a scattering sheet or fly-eye lens assembly, reduces the spatial coherence of laser light and ensures a uniform and continuous angular distribution

Methodology Applied
Scientific EffectScattering: Scattering

Implementation Method 2

The polarizing and splitting device includes a prism unit and a lens assembly, and is configured to convert light emitted from the projection apparatus into polarized light through the prism unit and the lens assembly

Methodology Applied
Scientific EffectPolarisation: Polarisation

Implementation Method 3

a laser generation unit configured to output laser light

Methodology Applied
Scientific EffectLaser: Laser

Data Source

PatentEP3982190B13D projection apparatus
Publication Date: 2025.06.04 APPOTRONICS CORP LTD
  • EP3982190B1 patent drawingFigure 1
  • EP3982190B1 patent drawingFigure 2
  • EP3982190B1 patent drawingFigure 3~4

AI summary

A light source device, comprising a laser generation unit (21), a light modification member (22), a light guide unit (23) and a dodging unit (24). The light modification element (22) may enable the laser beam angle to be uniformly distributed. The apparatus comprises a polarized beam splitting device (26), a light engine device (25) and a light source device, such a design may weaken the spatial coherence of the laser so as to make the laser beam angle to be distributed uniformly and continuously, thereby weakening the diffraction phenomena caused by the laser irradiating at a seam of the polarized beam splitting prism in a 3D device and greatly improving the viewing effect.