Waveguide Optical Scanner Actuation for Compact Micro Displays

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Solution Overview

Problem

Conventional miniature scanner technologies, particularly MEMS scanners, face limitations due to their complex structures and the need for larger scanning mirrors, which restrict the size and hence the resolution and field of view (FOV) of micro displays.

Innovation Solution

The use of a resonating fiber or micro fabricated waveguide in an optical scanning device to replace scanning mirrors, where the device includes a substrate with actuating members, a connecting member, and a waveguide that vibrates in two dimensions to generate a scan pattern.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If MEMS scanning mirrors are used, then scanning function is achieved, but device size increases and resolution/FOV are limited

Engineering Contradiction:

Improvedevice sizeVSAvoidresolution

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent extracts the scanning mirror from the system and replaces it with a waveguide that performs scanning through total internal reflection. The waveguide acts as both the optical path and the scanning element, eliminating the need for a separate scanning mirror and reducing overall device size while maintaining or improving resolution.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical scanning mirror system with an optical waveguide system that uses total internal reflection and evanescent field coupling. This substitution eliminates mechanical moving parts and uses optical field interactions to achieve scanning, resulting in a more compact design with higher potential resolution.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If scanning mirrors are used, then scanning is achieved, but structure becomes complicated with many components

Engineering Contradiction:

Improvestructure complexityVSAvoidsystem reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent merges the optical waveguide and scanning mechanism into a single integrated structure. The waveguide itself performs the scanning function through controlled bending and coupling, combining what were previously separate components (optical path and scanning mechanism) into one unified element, thereby reducing structural complexity and improving reliability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The waveguide structure serves multiple functions simultaneously: it guides light, performs scanning through bending, and enables coupling between optical paths. This multi-functionality reduces the number of separate components needed, simplifying the overall structure while maintaining system reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Object-generated harmful factors

If scanning mirrors are used, then scanning function is achieved, but additional diffractions are created at the output

Engineering Contradiction:

ImprovediffractionVSAvoidbeam quality

Core Design Contradiction:

Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical scanning mirror with an optical waveguide system that uses total internal reflection and evanescent field coupling. This substitution eliminates the edge diffraction problems inherent in mirror-based systems, as the waveguide confines and controls the optical field more effectively, reducing unwanted diffractions and improving beam quality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach allows for a more compact optical scanning device that can achieve higher scanning ranges and maintain high resolution and FOV, while also enabling the generation of various scan patterns by adjusting the driving signals.

Implementation Method 1

The two actuating members are actuated in a same dimension either in phase or out of phase simultaneously to drive the waveguide to vibrate in two dimensions to generate a scan pattern

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

utilize a resonating fiber or micro fabricated waveguide to replace scanning mirrors

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS20250067973A1Optical scanning device, micro display, micro imaging system and fabricating method of optical scanning device

Publication Date: 2025.02.27 NATIONAL TSING HUA UNIVERSITY

AI summary

An optical scanning device includes a substrate, two actuating members, a connecting member and a waveguide. The substrate includes two disposing portions and a connecting portion. The two disposing portions include two free ends and two fixed ends, and one of the two free ends is opposite to one of the two fixed ends. The connecting portion is connected to the two fixed ends of the two disposing portions. The two actuating members disposed side by side on the two disposing portions, respectively. The connecting member is connected to the two disposing portions. The waveguide is disposed between the two actuating members and penetrated through the connecting member. The two actuating members are actuated in a same dimension either in phase or out of phase simultaneously to drive the waveguide to vibrate linearly or nonlinear in two dimensions to generate a scan pattern.