Light Deflector with Laminated Silicon Support for Scanning Angle

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Solution Overview

Problem

Existing light deflectors face challenges in increasing the oscillation angle of the mirror unit, which limits the scanning angle, due to the rigidity of the piezoelectric member used.

Innovation Solution

The light deflector's rigidity is decreased by incorporating a supporting unit with a laminated structure of silicon active and oxide layers, allowing for increased deformation and thus a larger scanning angle, while maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the rigidity of the piezoelectric member is increased to maintain structural stability, then the structural stability is improved, but the oscillation angle decreases

Engineering Contradiction:
Improvestructural stabilityVSAvoidoscillation angle
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

The supporting unit is designed with non-uniform thickness, having a first thickness in the region where piezoelectric members are disposed and a second thickness in other regions. This local variation in thickness allows the structure to have different rigidity characteristics in different areas, enabling sufficient deformation for oscillation while maintaining overall structural stability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The light deflector employs a composite structure consisting of a supporting unit made from laminated silicon active and oxide layers. This composite material approach combines materials with different mechanical properties, allowing the structure to achieve both the necessary flexibility for oscillation and the required structural stability.

Inventive Principle:
Principle #40Composite materials

2Shape

If the oscillation angle is increased to increase the scanning angle, then the scanning angle is improved, but the structural integrity deteriorates

Engineering Contradiction:
Improvescanning angleVSAvoidstructural integrity
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The supporting unit has varying thickness across different regions, with a first thickness where piezoelectric members are disposed and a second thickness in other regions. This local quality variation enables the structure to deform sufficiently for increased oscillation angle while the thicker regions maintain structural integrity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The laminated structure of silicon active and oxide layers creates a composite material system that provides both the flexibility needed for larger oscillation angles and the strength required to maintain structural integrity during operation.

Inventive Principle:
Principle #40Composite materials

3Stability of the object's composition

If the thickness of the piezoelectric member is increased to maintain structural stability, then the structural stability is improved, but the deformation amount decreases

Engineering Contradiction:
Improvestructural stabilityVSAvoiddeformation amount
Core Design Contradiction:
Stability of the object's compositionVSLength of moving object

Solution Approach 1:

The supporting unit implements local quality through non-uniform thickness distribution, with a first thickness in the region where piezoelectric members are disposed and a second thickness in other regions. This allows the area requiring deformation to be thinner for greater displacement, while other areas are thicker for structural stability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The composite structure of laminated silicon layers with different thicknesses enables the system to achieve both sufficient deformation amount in the piezoelectric region and overall structural stability through the multi-layer construction.

Inventive Principle:
Principle #40Composite materials

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 scanning angle without compromising the structural stability, allowing for improved optical scanning capabilities even in miniaturized designs.

Implementation Method 1

A piezoelectric member is interposed between an upper electrode and a lower electrode. A voltage is applied across the upper and lower electrodes to oscillate a mirror unit to reflect light

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3494433B1Light deflector, optical scanning device, image projection device, and mobile object
Publication Date: 2022.02.16 RICOH CO LTD
  • EP3494433B1 patent drawingFigure 1
  • EP3494433B1 patent drawingFigure 2
  • EP3494433B1 patent drawingFigure 3

AI summary

A light deflector is provided including a mirror unit including a reflection plane, the mirror unit configured to rotate around a predetermined rotational axis, a pair of supporting beams configured to support the mirror unit in a rotatable manner, and drivers configured to drive the mirror unit to rotate, through the supporting beams. Each of the drivers has one end coupled to the supporting beams and another end coupled to a supporting unit formed to surround the mirror unit, and the supporting unit at least partially includes a thick portion and a thin portion different from each other in thickness.