Optical Scanning Device Wavelength Beam Steering

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Solution Overview

Problem

Existing optical scanning devices face challenges in achieving high resolution when a wide viewing angle is required due to mechanical limitations in reducing the deflection angle Δθ, which affects the optical scanning resolution.

Innovation Solution

The optical scanning device incorporates an optical mode converter that changes the radiation direction of light based on wavelength or phase changes, combined with an actuator rotating a mirror about two orthogonal shafts, enhancing scanning resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the deflection angle Δθ is reduced to improve resolution, then the optical scanning resolution is improved, but the viewing angle becomes limited due to mechanical structure constraints

Engineering Contradiction:
Improveoptical scanning resolutionVSAvoidviewing angle
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The optical scanning function is divided into two independent parts: a fixed mirror for wavelength/phase-based beam steering and a movable mirror for angular scanning. This segmentation allows each component to optimize its function without compromising the other, resolving the contradiction between resolution and viewing angle.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fixed mirror acts as an intermediary that converts wavelength or phase changes into radiation direction changes. This intermediary enables precise beam control without requiring the movable mirror to make fine adjustments, thus maintaining both high resolution and wide viewing angle capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the actuator rotates the mirror about two shafts to provide wide viewing angle, then the viewing angle is improved, but the resolution deteriorates due to inability to reduce deflection angle Δθ

Engineering Contradiction:
Improveviewing angleVSAvoidoptical scanning resolution
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The scanning function is segmented between a fixed mirror handling fine angular control via wavelength/phase modulation and a movable mirror handling coarse angular positioning. This allows the system to achieve both wide viewing angle and high resolution simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the purely mechanical approach of using a single movable mirror with a combination of optical control (wavelength/phase modulation) and mechanical scanning. This substitution enables precise beam direction control without being constrained by mechanical deflection angle limitations.

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

3Device complexity

If a single mirror is used for both scanning functions, then the device complexity is reduced, but the scanning resolution and viewing angle cannot be optimized simultaneously

Engineering Contradiction:
Improveactuator structureVSAvoidoptical scanning resolution
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The mirror system is segmented into two mirrors with distinct functions: one fixed mirror for high-resolution beam steering and one movable mirror for wide-angle scanning. This segmentation increases device complexity slightly but enables simultaneous optimization of both resolution and viewing angle, providing better overall performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fixed mirror serves multiple functions: it reflects light from the light source, converts wavelength/phase changes into direction changes, and directs light to the movable mirror. This multi-functionality justifies the additional component by consolidating several operations into a single element.

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

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 enhances the resolution of optical scanning by allowing precise control of light radiation directions, improving scanning accuracy and coverage without the mechanical constraints of traditional two-shaft actuator systems.

Implementation Method 1

an optical mode converter connected to an optical waveguide through which the light output from the light source transmits, and configured to radiate the light received through the optical waveguide, wherein the optical mode converter is configured to change a radiation direction of the light to be transmitted from the optical mode converter, in accordance with a change in wavelength of the light output from the light source or phase of the light output from the light source

Methodology Applied
Scientific EffectOptical mode conversion: Waveguide (optics)

Implementation Method 2

a mirror arranged around the optical mode converter, and configured to reflect the light radiated from the optical mode converter and then reflected from an object, toward an optical receiver

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4155760B1Optical scanning device and ranging apparatus
Publication Date: 2025.04.02 MITSUBISHI ELECTRIC CORP
  • EP4155760B1 patent drawingFigure 1
  • EP4155760B1 patent drawingFigure 2
  • EP4155760B1 patent drawingFigure 3~5

AI summary

An optical scanning device (2) includes an optical mode converter (5) to change, in accordance with a change in wavelength of a light output from a light source (1) or phase of the light output from the light source (1), a radiation direction of the light, and an actuator (7) to rotate the optical mode converter (5) about each of two shafts orthogonal to each other.