Slit Torsion Bar Light Deflector for Wider Scan Angles

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Solution Overview

Problem

Existing light deflectors face limitations in maximum reciprocating rotation angle due to torsion bar stress, leading to potential damage and reduced scanning angle, with existing designs either narrowing the torsion bar width or thickness, which increases harmonics and load on actuators.

Innovation Solution

A light deflector design with slits in the torsion bars, where both ends are closed in the front view, dispersing stress across the side surfaces and inner slit surfaces, allowing for increased maximum allowable rotation angle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the torsion bar width or thickness is narrowed to increase the maximum reciprocating rotation angle, then the scanning angle is improved, but the torsion bar strength is reduced and harmonics are increased

Engineering Contradiction:

Improvemaximum reciprocating rotation angleVSAvoidtorsion bar strength

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The torsion bar is segmented by forming slits that divide the bar into multiple sections. This segmentation allows the torsion bar to flex more easily during reciprocating rotation, increasing the maximum rotation angle without compromising overall strength. The slits create multiple stress distribution zones that prevent stress concentration at any single point.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The slits are positioned at specific locations along the torsion bar where stress concentration is most likely to occur. By creating local structural modifications at these critical positions, the design allows for increased flexibility in the regions needing movement while maintaining stronger sections where structural integrity is most important.

Inventive Principle:

Principle #3Local quality

2Length of moving object

If the torsion bar width or thickness is narrowed to increase the maximum reciprocating rotation angle, then the scanning angle is improved, but the harmonics are increased

Engineering Contradiction:

Improvemaximum reciprocating rotation angleVSAvoidharmonics

Core Design Contradiction:

Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The slits divide the torsion bar into segments that can move independently to some degree, which smooths out the motion characteristics and reduces harmonic vibrations. This segmentation allows for more gradual stress transitions during reciprocating rotation, decreasing the generation of harmful harmonics.

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If the two torsion bars on each side are completely opened by a gap extending in the width direction, then the manufacturing is simplified, but the transmission efficiency of rotation force is lowered

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidtransmission efficiency of rotation force

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

Instead of completely opening the torsion bars with full gaps, the design applies partial action by forming slits that are open at certain positions but closed at others. This partial opening approach maintains sufficient structural continuity to ensure efficient force transmission while still providing enough flexibility to achieve the desired rotation angle.

Inventive Principle:

Principle #16Partial or excessive action

4Stability of the object's composition

If coupling points are separated from each other with respect to the rotation axis, then the structural stability is improved, but the rotation drive force and inversion drive force are increased

Engineering Contradiction:

Improvestructural stabilityVSAvoidrotation drive force

Core Design Contradiction:

Stability of the object's compositionVSForce

Solution Approach 1:

The separated coupling points create a segmented structure that enhances stability by distributing loads across multiple attachment points. The slits between these coupling points allow for controlled flexibility, enabling the structure to maintain stability while requiring less drive force compared to a fully rigid coupled structure.

Inventive Principle:

Principle #1Segmentation

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 slit design reduces stress concentration, increasing the maximum allowable rotation angle by 25% and improving drive efficiency by 29%, while maintaining structural integrity and reducing harmonics.

Implementation Method 1

a piezoelectric actuator that is coupled to a distal end-side end portion of each torsion bar and reciprocally rotates the torsion bar around the rotation axis

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

reflects an incident laser beam onto a mirror portion that reciprocally rotates around a rotation axis, and emits reflected light as scanning light from the mirror portion

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS20260103376A1Light deflector

Publication Date: 2026.04.16 STANLEY ELECTRIC CO LTD

AI summary

A light deflector includes a mirror portion, torsion bars and extending from each side of the mirror portion along a rotation axis, inner actuators and coupling to outer coupling regions of the torsion bars and from both sides and reciprocally rotating the torsion bars and around the rotation axis, and a slit and a slit formed in the torsion bars and having closed both ends and extending along the rotation axis over a length range that reaches an inner coupling region and an outer coupling region.