Movable Condenser Lens for Multi-Pattern DOE Generation

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Solution Overview

Problem

Conventional light pattern generators using diffractive optical elements require multiple elements for different light patterns, increasing complexity and cost, especially when varying wavelengths are involved.

Innovation Solution

A light pattern generator configuration utilizing a single diffractive optical element, a laser light source, a condenser lens, and a mask, where the condenser lens shifts between focal length positions to collimate or converge light, enabling the production of multiple patterns by modulating the phase distribution of light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple diffractive optical elements are used to produce different light patterns, then the variety of light patterns increases, but the device complexity and cost increase

Engineering Contradiction:
Improvevariety of light patternsVSAvoidnumber of diffractive optical elements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the condenser lens movable along the optical axis. By dynamically adjusting the position of the condenser lens, the system can switch between different light patterns (collimated or converging) using a single diffractive optical element, thereby resolving the contradiction between pattern variety and device complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements universality by designing a single diffractive optical element that can serve multiple functions. Through the movable condenser lens, one diffractive optical element can generate multiple different light patterns, eliminating the need for multiple specialized elements and reducing overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If liquid crystal is used to switch light patterns, then pattern switching capability is achieved, but device size and cost increase

Engineering Contradiction:
Improvepattern switching capabilityVSAvoiddevice size and cost
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the liquid crystal-based optical modulation system with a simpler mechanical positioning system. Instead of using liquid crystal to dynamically change refractive indices, the invention uses a movable condenser lens to physically adjust light convergence, achieving pattern switching with reduced device complexity and cost

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical parameter of the condenser lens position along the optical axis to achieve pattern switching. By varying this mechanical parameter, the system can switch between different light patterns without requiring complex liquid crystal control systems, thereby simplifying the overall device

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

Enables the production of multiple light patterns using a single diffractive optical element, reducing complexity and cost while maintaining high optical energy efficiency.

Implementation Method 1

A diffractive optical element (DOE) is an element which is a substrate having periodically arranged slits and/or uneven shapes. The diffractive optical element uses diffractive light generated by the effects of the slits and/or the uneven shapes, to convert incident light into light having an intended intensity distribution.

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

a condenser lens to refract the laser light outputted from the laser light source

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3712687B1Optical pattern generation device
Publication Date: 2022.02.02 MITSUBISHI ELECTRIC CORP
  • EP3712687B1 patent drawingFigure 1
  • EP3712687B1 patent drawingFigure 2
  • EP3712687B1 patent drawingFigure 3

AI summary

Alight pattern generator of the present disclosure includes: a laser light source to output laser light; a condenser lens to refract the laser light outputted from the laser light source; a mask to absorb or reflect part of the refracted light outputted from the condenser lens, the mask transmitting the rest of the refracted light; and a diffractive optical element to change a phase of the transmitted light in accordance with a position on a plane perpendicular to a direction in which the light transmitted through the mask travels and to output light having a phase distribution to form a light pattern, wherein the condenser lens is placed at a first position which is the condenser lens's focal length distant from the laser light source. This configuration makes it possible to form a plurality of types of light patterns by using a single diffractive optical element.