Optical Scanner Projection Portion for Dynamic Bending Reduction

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Solution Overview

Problem

Existing optical scanners face challenges in reducing dynamic bending of the movable plate while maintaining accurate scanning characteristics, leading to increased size due to the need for thicker components to mitigate deformation.

Innovation Solution

The optical scanner design incorporates a projection portion on the movable plate that extends beyond the first axis portion, positioned to reduce dynamic bending without increasing the thickness of the axis portion, and includes a rib for enhanced rigidity and a positioning portion to accurately place the permanent magnet, preventing contact and minimizing inertia.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the thickness of the movable plate is increased to reduce dynamic bending, then the scanning accuracy is improved, but the size of the optical scanner increases

Engineering Contradiction:

Improvescanning accuracyVSAvoidsize of optical scanner

Core Design Contradiction:

Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The invention transitions from increasing thickness (one dimension) to extending in the planar direction (another dimension). The projection portion extends from the movable plate in the direction away from the fixed plate, creating a lever arm that reduces dynamic bending without increasing component thickness, thereby solving the contradiction between scanning accuracy and scanner size.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The projection portion is positioned in advance at a location that overlaps the first oscillation axis to preemptively counteract dynamic bending forces. By placing the projection portion at this specific position before oscillation occurs, the inertial force naturally acts to reduce bending during operation, achieving high scanning accuracy without increasing size.

Inventive Principle:

Principle #10Preliminary action

2Strength

If the thickness of the axis member is increased to support the thicker movable plate, then the structural strength is improved, but the length of the axis member must be increased, resulting in increased scanner size

Engineering Contradiction:

Improvestructural strengthVSAvoidlength of axis member

Core Design Contradiction:

StrengthVSLength of stationary object

Solution Approach 1:

Instead of increasing axis member thickness (one dimension) and consequently its length (another dimension), the invention uses the projection portion extending in the thickness direction of the movable plate to provide the necessary structural support. This approach maintains axis member dimensions while achieving the required strength through the projection portion's lever arm effect.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If the projection portion extends beyond the first axis portion to reduce dynamic bending, then the scanning accuracy is improved, but the risk of contact with the permanent magnet increases

Engineering Contradiction:

Improvescanning accuracyVSAvoidcontact with permanent magnet

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The projection portion is designed with specific local characteristics: it overlaps the first oscillation axis to reduce bending, but its extent in the thickness direction is carefully controlled to stop before contacting the permanent magnet. This localized design achieves the bending reduction benefit while avoiding the harmful contact effect.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The projection portion's position is predetermined to create a counterbalancing effect against dynamic bending before oscillation begins. By positioning it to overlap the first oscillation axis, the design preemptively counteracts bending forces while its limited extension prevents contact with the permanent magnet, avoiding harmful interactions.

Inventive Principle:

Principle #9Preliminary anti-action

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 effectively reduces dynamic bending, achieves highly accurate optical scanning, and miniaturizes the scanner by maintaining the size without increasing the thickness of the axis portion, enabling high-quality image display in devices like head-mounted and heads-up displays.

Implementation Method 1

a permanent magnet provided in the frame body portion

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

a movable plate on which a light reflecting portion, which reflects light, is provided

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS10989918B2Optical scanner, image display device, head-mounted display, and heads-up display

Publication Date: 2021.04.27 SEIKO EPSON CORP

AI summary

An optical scanner includes a movable portion having a movable plate on which a light reflecting portion is provided, a frame body portion provided surrounding the movable portion when viewed in a planar manner, a first axis portion that oscillatably supports the movable portion around a first oscillation axis, a second axis portion that oscillatably supports the frame body portion around a second oscillation axis, which intersects the first oscillation axis, and a permanent magnet provided in the frame body portion, in which the movable portion has a projection portion, which is disposed overlapping the first oscillation axis within a region that does not overlap with the permanent magnet when viewed in a planar manner, and which projects, from the movable plate, further to the permanent magnet side than the first axis portion.