Laser Scan Optics Mounting With Thermal Expansion Compliance

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Solution Overview

Problem

Existing mounting methods for lenses and mirrors in laser scanning devices are prone to failures due to thermal expansion and contraction, leading to adhesive bond breakage, plastic deformation, and optical component misalignment, which affect the laser beam's pointing and focus.

Innovation Solution

A mounting mechanism with a rigid first mounting member and a flexible second mounting member that allows movement only in the direction of thermal expansion, preventing material deformation and adhesive bond failure, while maintaining optical component alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If adhesive bonding is used to mount lenses and mirrors, then manufacturing cost is reduced, but reliability deteriorates due to thermal expansion mismatch causing adhesive bond breakage

Engineering Contradiction:

Improvemanufacturing costVSAvoidadhesive bond strength

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The mounting structure is divided into multiple independent mounting members (first mounting member and second mounting member) that are separately attached to the housing. Each mounting member independently supports a portion of the optical component, distributing the thermal stress and preventing single-point bond failure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mounting members are designed with different flexibility characteristics - the first mounting member is rigid while the second mounting member is flexible. This parameter differentiation allows the system to maintain structural integrity while accommodating thermal expansion through controlled deformation of the flexible member.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If rigid mounting is used to maintain precise optical alignment, then manufacturing precision is improved, but reliability worsens due to plastic deformation from thermal expansion forces

Engineering Contradiction:

Improveoptical component alignmentVSAvoidresistance to plastic deformation

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

Different regions of the mounting structure have different mechanical properties. The first mounting member is designed with rigid local quality to maintain precise positioning, while the second mounting member has flexible local quality to absorb thermal expansion forces, preventing plastic deformation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The mounting structure transitions from a completely static rigid mounting to a dynamic system where the flexible mounting member can deform elastically in response to thermal forces, then return to its original position, maintaining optical alignment while accommodating temperature changes.

Inventive Principle:

Principle #15Dynamics

3Ease of manufacture

If adhesive bonding is used to reduce cost, then ease of manufacture is improved, but manufacturing precision deteriorates due to elastic deformation causing beam pointing and focus shifts

Engineering Contradiction:

Improvemounting method simplicityVSAvoidbeam pointing and focus accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The flexible mounting member acts as an intermediary between the rigid housing and the optical component. It mediates the thermal expansion forces, allowing the optical component to maintain its precise alignment while the mounting member undergoes elastic deformation, thus preserving beam pointing and focus accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution effectively reduces stress-related failures by allowing thermal expansion and contraction movement, maintaining optical component alignment and preventing misalignment, thus ensuring stable laser beam pointing and focus.

Implementation Method 1

The outer end portion of the second mounting member flexibly moving relative to the base in response to a change in temperature

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

What is generally desired is for any deformation to be elastic in nature so that when the forces subside, the components return to their original position

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS20110315836A1Mounting Mechanism for a Component of an Imaging Apparatus, and Methods of Making and Using Same

Publication Date: 2011.12.29 LEXMARK INTERNATIONAL INC

AI summary

A laser scan unit for an imaging apparatus, including an optical paths having a plurality of optical components for directing and focusing a light beam. A component mounting mechanism is employed having a first member which is substantially fixed and resistant to movement, and a second member having an end portion which flexibly moves in response to forces acting thereon that are generated by changes in temperature due to differences in thermal expansion between the component and the first and second members.