Segmented Diffraction Device for Laser Illuminator Speckle Reduction

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Solution Overview

Problem

Existing projectors using multiple laser light sources with different peak wavelengths for color display face challenges in generating clear illumination images due to wavelength variations, leading to blurring and speckle issues, as current techniques are limited by narrow wavelength widths and require specific diffraction patterns for each color.

Innovation Solution

An illuminator and projector design that includes a light source unit emitting colored light with multiple peak wavelengths and a diffraction device with divided areas, each optimized for a specific peak wavelength, allowing individual light entry and reducing speckle by superimposing diffracted light on a target surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple laser light sources with different peak wavelengths are used for color display, then color variety is improved, but image clarity deteriorates due to wavelength variations causing blurring and speckle

Engineering Contradiction:

Improvecolor varietyVSAvoidimage clarity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The diffraction device is divided into multiple divided areas, with each area optimized for a specific peak wavelength. This segmentation allows each region to handle a specific wavelength component independently, preventing the blurring that occurs when multiple wavelengths interfere with a single diffraction pattern, thereby maintaining image clarity while using multiple laser sources for color display.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different divided areas of the diffraction device have different diffraction patterns optimized for specific wavelengths. This local optimization ensures that each wavelength component is diffracted according to its specific characteristics, reducing speckle and blurring effects while preserving the color variety provided by multiple laser sources.

Inventive Principle:

Principle #3Local quality

2Device complexity

If a single diffraction device is used for multiple wavelengths, then device complexity is reduced, but image quality deteriorates due to wavelength-dependent blurring

Engineering Contradiction:

Improvedevice structureVSAvoidimage quality

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The diffraction device is segmented into multiple divided areas, each with diffraction patterns optimized for specific peak wavelengths. This segmentation approach maintains a single physical device structure while achieving wavelength-specific optimization, thus reducing overall device complexity compared to using separate devices for each wavelength while preventing wavelength-dependent blurring.

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If laser light sources with narrow wavelength widths are used, then color purity is improved, but image clarity deteriorates due to speckle formation

Engineering Contradiction:

Improvecolor purityVSAvoidspeckle

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

By segmenting the diffraction device into multiple wavelength-specific divided areas, the patent reduces speckle formation caused by narrow wavelength widths. Each divided area handles a specific wavelength component independently, preventing the coherent interference that causes speckle while maintaining the color purity provided by narrow wavelength widths.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each divided area has a diffraction pattern locally optimized for its specific wavelength range. This local optimization reduces speckle formation by ensuring that each wavelength component is diffracted according to its specific characteristics, while still maintaining the color purity achieved through narrow wavelength widths.

Inventive Principle:

Principle #3Local quality

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 approach enables the generation of clear illumination images with reduced speckle and wavelength-dependent blurring, improving image quality and efficiency by optimizing diffraction patterns for each peak wavelength.

Implementation Method 1

a diffraction device that includes a plurality of divided areas, and displays, in each of the divided areas, a diffraction pattern that is optimized at a corresponding peak wavelength

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS11356644B2Illuminator and projector

Publication Date: 2022.06.07 SONY GROUP CORP

AI summary

An illuminator of the present disclosure includes a light source unit that emits at least one colored light, and emits, for each of the pieces of colored light, light having a plurality of peak wavelengths different from each other, and a diffraction device that includes a plurality of divided areas, and displays, in each of the divided areas, a diffraction pattern that is optimized at a corresponding peak wavelength out of each of the peak wavelengths. The plurality of divided areas allows the light of the plurality of peak wavelengths to enter the plurality of divided areas individually for each of the pieces of colored light.