Piezoelectric Sensor in Outermost Cantilever for Optical Deflector

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Solution Overview

Problem

Existing two-dimensional optical deflectors face challenges in accurately controlling the flexing amounts of piezoelectric actuators due to reduced rocking forces and high-frequency signal detection issues caused by the placement of sense elements within the actuators, leading to decreased deflection angles and increased wiring resistance.

Innovation Solution

Incorporating piezoelectric sensors into the outermost cantilevers of meander-type piezoelectric actuators, which increases the provision area for drive elements, strengthens rocking forces, and allows for accurate control of actuator flexing by enhancing high-frequency signal detection without crosstalk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sense elements are provided in the entire piezoelectric actuators, then the flexing amounts can be sensed, but the provision area of drive elements is decreased and rocking forces are weakened

Engineering Contradiction:

Improvesensing accuracyVSAvoidrocking force

Core Design Contradiction:

Measurement precisionVSForce

Solution Approach 1:

The piezoelectric actuator is divided into multiple piezoelectric cantilevers, with only the outermost cantilever containing both drive and sense elements. This segmentation allows other cantilevers to be dedicated solely to driving, increasing the total drive element area and rocking force while the outermost cantilever provides sensing capability.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If long wiring lines are required to be connected to drive elements and sense elements, then the actuators can be controlled, but the resistance of wiring lines is increased

Engineering Contradiction:

Improvecontrol capabilityVSAvoidwiring resistance

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The drive elements and sense elements are merged into the same outermost piezoelectric cantilever structure, allowing both functions to be implemented in a compact arrangement. This reduces the distance between elements and minimizes wiring line length, thereby reducing wiring resistance and energy loss.

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If the width of drive elements and sense elements is made very small for fine manufacturing, then the optical deflector can be miniaturized, but high frequency sense signals cannot be detected due to crosstalk

Engineering Contradiction:

Improveminiaturization capabilityVSAvoidsignal detection accuracy

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The sensing function is moved to the outermost cantilever in a spatial arrangement that separates it from other drive elements. This dimensional repositioning increases the spacing between sense elements and adjacent drive elements, reducing electromagnetic crosstalk and enabling accurate high-frequency signal detection while maintaining miniaturized dimensions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 increases deflection angles, reduces wiring resistance, and enables precise control of actuator flexing, improving the accuracy and efficiency of optical deflection in two-dimensional optical deflectors.

Implementation Method 1

at least one piezoelectric sensor is provided for sensing rocking vibrations of the mirror caused by the first and second piezoelectric actuators

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a first piezoelectric actuator, connected between the movable frame and the mirror, for rocking the mirror with respect to a first axis of the mirror

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS9151947B2Optical deflector including piezoelectric sensor incorporated into outermost piezoelectric cantilever

Publication Date: 2015.10.06 STANLEY ELECTRIC CO LTD

AI summary

In an optical deflector including a mirror, a movable frame supporting the mirror, a first piezoelectric actuator for rocking the mirror with respect to a first axis of the mirror, a support body supporting the movable frame, and a second piezoelectric actuator for rocking the mirror through the movable frame with respect to a second axis of the mirror, at least one piezoelectric sensor is provided for sensing rocking vibrations of the mirror caused by the first and second piezoelectric actuators. The second piezoelectric actuator includes a pair of meander-type piezoelectric actuators opposite to each other with respect to the first axis. Each of the second meander-type piezoelectric actuators includes a plurality of piezoelectric cantilevers folded at every cantilever and connected from the support body to the movable frame in parallel with the first axis. The piezoelectric sensor is incorporated into an outermost one of the piezoelectric cantilevers.