Optical Scan Device Using Waveguide Refractive Index Control

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Solution Overview

Problem

Conventional optical scanning devices are complex and prone to vibration, with existing technologies requiring intricate structures and mechanisms for two-dimensional scanning, such as rotating mirrors and phase shifters, which complicate the design and limit robustness and scanning range.

Innovation Solution

An optical scanning device utilizing a waveguide element with a pair of mirrors and an optical waveguide layer, where the refractive index and thickness of the waveguide layer are adjusted to change the emission angle of light, allowing for one-dimensional and two-dimensional scanning without the need for complex structures or phase shifting mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If rotating mirrors and phase shifters are used for optical scanning, then scanning functionality is achieved, but device complexity increases

Engineering Contradiction:
Improvescanning functionalityVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical rotating mirrors with a waveguide-based optical system. Light is guided through a waveguide layer with controlled total internal reflection, eliminating the need for mechanical moving parts while achieving the same beam deflection function. This substitution of mechanical systems with optical waveguide principles directly resolves the contradiction between scanning functionality and device complexity.

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

Solution Approach 2:

The patent extracts and eliminates the phase shifter component from the optical scanning system. By using a waveguide structure with controlled reflection at the waveguide-cladding interface, the system achieves phase control inherently through the waveguide geometry and refractive index distribution, removing the need for separate phase shifting mechanisms and thereby reducing overall device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If rotating mirrors and phase shifters are used for optical scanning, then scanning functionality is achieved, but vibration increases

Engineering Contradiction:
Improvescanning functionalityVSAvoidvibration resistance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces mechanical rotating mirrors with a static waveguide-based optical system. The beam deflection is achieved through controlled total internal reflection at the waveguide-cladding interface, which is determined by the waveguide's refractive index and geometry rather than mechanical motion. This eliminates vibration inherent in rotating mirror systems while maintaining scanning functionality, directly improving reliability.

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

3Adaptability or versatility

If intricate structures and mechanisms are used for two-dimensional scanning, then scanning range is improved, but device complexity increases

Engineering Contradiction:
Improvescanning rangeVSAvoidmechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent achieves two-dimensional scanning control through the waveguide layer's refractive index and thickness parameters rather than adding more mechanical dimensions. By controlling the effective refractive index and waveguide thickness, the system can independently adjust horizontal and vertical beam deflection angles, achieving 2D scanning through optical parameter control instead of complex mechanical mechanisms.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent uses parameter changes in the waveguide structure (refractive index and thickness) to control beam deflection. By varying the effective refractive index of the waveguide layer and adjusting its thickness, the system can dynamically control the emission angle and scanning range without requiring additional mechanical components or complex mechanisms, thereby expanding scanning range while keeping device complexity low.

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

The solution enables simple and robust optical scanning with reduced complexity, achieving effective one-dimensional and two-dimensional scanning by controlling the refractive index and thickness of the waveguide layer, enhancing scanning range and stability.

Implementation Method 1

an optical waveguide layer 20 that propagates light inputted to the first waveguide and transmitted through the first waveguide

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

The first mirror has a higher light transmittance than the second mirror and allows part of the light propagating through the optical waveguide layer to be emitted to the outside

Methodology Applied
Scientific EffectLight transmittance and reflection: Reflection

Implementation Method 3

an adjusting element that changes at least one of the refractive index and thickness of the optical waveguide layer to thereby change the direction of the emitted light

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3521919B1Optical scan device, light receiving device, and optical detection system
Publication Date: 2024.11.27 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3521919B1 patent drawingFigure 1
  • EP3521919B1 patent drawingFigure 2
  • EP3521919B1 patent drawingFigure 3

AI summary

An optical scanning device includes: a first waveguide that propagates light in a waveguide direction by total reflection; and a second waveguide. The second waveguide includes: a first multilayer reflective film; a second multilayer reflective film that faces the first multilayer reflective film; and a first optical waveguide layer that is connected directly to the first waveguide and located between the first multilayer reflective film and the second multilayer reflective film. The first optical waveguide layer has a variable thickness and/or a variable refractive index for the light and propagates the light transmitted through the first waveguide. The first multilayer reflective film has a higher light transmittance than the second multilayer reflective film and allows part of the light propagating through the first optical waveguide layer to be emitted to the outside of the second waveguide. By changing the thickness of the first optical waveguide layer and/or the refractive index thereof for the light, the direction of the part of the light emitted from the second waveguide is changed.