Electro-Optic Photonic Crystal Waveguide for Large-Angle Scanning

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Solution Overview

Problem

Existing optical scanning devices face limitations in scan angle, require multiple light sources for different wavelengths, and have slow response times due to wavelength-dependent deflection or heating mechanisms.

Innovation Solution

A waveguide device with a photonic crystal layer, line-defect optical waveguide, and electrodes arranged above and below the electro-optical crystal substrate, allowing for efficient electric field generation and reduced driving voltage, enabling large scan angles and quick responsiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a light deflector with wavelength-dependent deflection angle is used, then the device can be manufactured with simpler structure, but multiple light sources having different wavelengths are required and the scan angle is insufficient

Engineering Contradiction:

Improvestructure complexityVSAvoidscan angle

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by utilizing the electro-optical effect to dynamically alter the refractive index of the waveguide material in response to applied voltage. This enables the deflection angle to be controlled electrically rather than being fixed by wavelength-dependent structural parameters, achieving large scan angles with a single light source while maintaining structural simplicity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical or thermal adjustment mechanisms with an electro-optical field-based control system. By applying voltage to change the refractive index, the system achieves rapid response without mechanical moving parts or thermal heating, resolving the contradiction between structural simplicity and scan angle capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If heating mechanism is used to change deflection angle, then the device can be manufactured with simpler structure, but the response is slow

Engineering Contradiction:

Improvestructure complexityVSAvoidresponse speed

Core Design Contradiction:

Device complexityVSSpeed

Solution Approach 1:

The patent substitutes thermal heating mechanisms with direct electro-optical field control. By applying voltage to change the refractive index through the electro-optical effect, the system achieves instantaneous response without the thermal inertia and heat transfer delays inherent in heating-based mechanisms, while maintaining structural simplicity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from temperature (thermal mechanism) to electric field strength (electro-optical mechanism). This parameter change enables rapid response by eliminating thermal time constants and achieving direct control of the refractive index through applied voltage

Inventive Principle:

Principle #35Parameter changes

3Speed

If electrodes are arranged above and below the electro-optical crystal substrate to overlap the optical waveguide, then the driving voltage is reduced and response is quick, but the device requires precise alignment and fabrication precision

Engineering Contradiction:

Improveresponse speedVSAvoidalignment precision

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent applies the nesting principle by integrating the electrodes directly into the waveguide structure itself. The electrodes are positioned within the waveguide regions, nested within the overall device footprint, which automatically provides precise alignment through the manufacturing of the waveguide structure rather than requiring separate alignment processes

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent merges the electrode structure with the waveguide structure into a single integrated component. By combining these elements, the patent eliminates the need for separate alignment procedures and reduces the number of fabrication steps, achieving both rapid response and manufacturability

Inventive Principle:

Principle #5Merging (Combining)

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 device achieves a large scan angle, rapid response, and reduced voltage requirements, facilitating cost-effective and efficient scanning with a single light source, suitable for applications like LiDAR.

Implementation Method 1

a photonic crystal layer having holes periodically formed in an electro-optical crystal substrate

Methodology Applied

Scientific EffectElectro-optical effect: Electro-Optic Effects

Implementation Method 2

a photonic crystal layer having holes periodically formed in an electro-optical crystal substrate

Methodology Applied

Scientific EffectPhotonic crystal effect: Photonic Crystal

Data Source

PatentUS12436442B2Waveguide device, optical scanning device and optical modulation device

Publication Date: 2025.10.07 NGK INSULATORS LTD

AI summary

A waveguide device includes: a photonic crystal layer having holes periodically formed in an electro-optical crystal substrate; a line-defect optical waveguide formed in the photonic crystal layer; a first electrode arranged above the electro-optical crystal substrate, the first electrode being transparent to light; and a second electrode arranged below the electro-optical crystal substrate. Each of an optical scanning device and an optical modulation device includes the above-mentioned waveguide device.