Micro-lens Array Diffuser for Laser Speckle Suppression

Solution Overview

Problem

Conventional head-up displays (HUDs) using obscure glass diffusers suffer from irregular image shading and laser sparkle noises due to the rough surface of the diffuser, leading to unfavorable image quality and limited resolution.

Innovation Solution

An optical device featuring a first lens array with micro-lens units arranged in a polygonal, circular, or ellipsoidal shape, and a second lens array with columnar lenses, which together diffuse the image beam to suppress speckle noises and improve image quality by reducing laser interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If obscure glass is used as a diffuser, then the virtual image display can be implemented, but irregular image shading and laser sparkle noises occur due to the rough surface

Engineering Contradiction:

Improveease of manufactureVSAvoidimage quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the surface parameters of the diffuser from a rough obscure glass surface to a precisely controlled micro-lens array structure with specific geometric parameters (lens diameter, pitch, depth, curvature radius), thereby eliminating irregular shading and laser sparkle while maintaining manufacturability through standardized optical element production

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent transitions from a homogeneous obscure glass material to a composite optical structure consisting of multiple micro-lens elements arranged in a specific pattern, where each micro-lens is a discrete optical component with controlled refractive properties, achieving superior image quality through structured composition

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If obscure glass with rough surface is used as diffuser, then the display function is achieved, but the image resolution is limited

Engineering Contradiction:

Improveease of manufactureVSAvoidimage resolution

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent changes the surface parameters of the diffuser from a rough obscure glass surface to a precisely controlled micro-lens array structure with specific geometric parameters (lens diameter, pitch, depth, curvature radius), thereby eliminating irregular shading and laser sparkle while maintaining manufacturability through standardized optical element production

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the continuous rough surface of obscure glass into discrete micro-lens elements arranged in a regular array pattern, where each micro-lens acts as an independent optical unit with controlled dimensions and spacing, thereby achieving higher image resolution through structured segmentation

Inventive Principle:

Principle #1Segmentation

3Productivity

If conventional diffuser is used, then the projection function works, but speckle contrast is high and image quality is unfavorable

Engineering Contradiction:

Improveprojection functionVSAvoidimage quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the surface parameters of the diffuser from a rough obscure glass surface to a precisely controlled micro-lens array structure with specific geometric parameters (lens diameter, pitch, depth, curvature radius), thereby eliminating irregular shading and laser sparkle while maintaining manufacturability through standardized optical element production

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful coherent interference effects (laser sparkle and high speckle contrast) into beneficial uniform diffusion by using the micro-lens array to deliberately structure the light paths, where the regular geometric arrangement of micro-lenses transforms coherent laser light into uniform diffuse illumination, eliminating the harmful interference patterns

Inventive Principle:

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

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 significantly reduces speckle contrast and enhances image quality by effectively diffusing the image beam, providing a higher light field utilization rate and minimizing noticeable patterns, thus improving the overall performance of the projection apparatus.

Implementation Method 1

a first lens array having a plurality of micro-lens units arranged into an array... which together diffuse the image beam to suppress speckle noises

Methodology Applied

Scientific EffectDiffusion: Scattering

Data Source

PatentUS9851560B2Optical device and projection apparatus

Publication Date: 2017.12.26 IND TECH RES INST

AI summary

An optical device including a first lens array is provided. The first lens array has micro-lens units arranged in an array. An outline of each of the micro-lens units is polygonal-shaped, circular or ellipsoidal. Moreover, a projection apparatus is also provided.