Handbook of Optomechanical Engineering

Anees Ahmad

• Publisher: CRC Press
• Year: 2017
• Print ISBN:
  9781498761482
• Edition: 2
• eBook ISBN:
  9781351649278
• Topic: Technology & Engineering
• Subtopic: Civil Engineering
• Index: Technology & Engineering

This comprehensive handbook covers all major aspects of optomechanical engineering - from conceptual design to fabrication and integration of complex optical systems. The practical information within is ideal for optical and optomechanical engineers and scientists involved in the design, development and integration of modern optical systems for commercial, space, and military applications. Charts, tables, figures, and photos augment this already impressive text. Fully revised, the new edition includes 4 new chapters: Plastic optics, Optomechanical tolerancing and error budgets, Analysis and design of flexures, and Optomechanical constraint equations.

1Optomechanical Engineering Basics

Robert Parks, Ron Willey, and Frédéric Lamontagne

1.1Introduction

1.1.1What Is Optomechanics?

1.1.2Role of Optomechanical Design and Its Significance

1.2Geometric Optics Fundamentals

1.2.1Basic Terminology

1.2.2Graphical Tools in Geometrical Optics and System Layouts

1.2.2.1Image Position and Magnification

1.2.2.2Amount of Light through a Lens System

1.2.3Additional CAD Techniques for Design and Ray Tracing

1.3Drawings of Optical Components and Systems

1.3.1Units of Measurement

1.3.2ISO and ANSI Drafting Standards

1.3.2.1Mechanical Drawing Standards

1.3.2.2Optical Drawing Standards

1.4Dimensional Tolerances and Error Budgets

1.4.1Effect of Tolerances on Cost

1.4.1.1Interactions of Lenses and Mounts

1.4.2Allocation of Tolerances

1.4.2.1Assigning Tolerances—An Example

1.4.3Current Trends in Tolerancing

1.5Environmental Effects

1.5.1Survivability under Temperature, Vibration, and Shock Loads

1.5.2Humidity, Corrosion, Contamination

1.5.3Environmental Testing Standards

1.5.3.1ISO 10109:2015—Guidance for the Selection of Environmental Tests

1.5.4Summary of Environmental Effects

References

1.1Introduction

This handbook consists of chapters written by authors of considerable experience in the practical application of optomechanics and covers a broad range of related subjects. In this chapter, we introduce general background information, techniques, and concepts which may be useful to the practitioners of optomechanics. These topics include definitions, fundamentals of geometrical optics, drawing standards, tolerancing concepts, and environmental effects.

1.1.1What Is Optomechanics?

We will define optomechanics as the science, engineering, and/or art of maintaining the proper shapes and positions of the functional elements of an optical system so that the system performance requirements are satisfied.

The issues with the original Hubble Space Telescope (HST) were attributed to an optomechanical error in the relative positioning of two mirror surfaces in the null corrector used to test the primary mirror. Great pains were undoubtedly taken in the design and construction of the HST, which was a major achievement in the field of optomechanics. Aside from its well-publicized technical issues, it still is a good example of the application of optomechanics. The shape and the position of the functional elements such as the primary and secondary mirrors must be maintained very precisely in order for the instrument to obtain results not previously achieved. The repairs made to the HST in 1993 have allowed most of the original scientific goals to be attained and continues to provide phenomenal images of our universe to this day.

Another example of optomechanics at the other extreme is the pair of eyeglasses that many of us wear. The frame must hold the lenses such that their principal points and astigmatic correction are in the right position and orientation with respect to the user’s eyes to within appropriate tolerances. The frame must also interface with the user’s head in a comfortable and reliable way, and the whole system must perform and survive in a variety of environments.

1.1.2Role of Optomechanical Design and Its Significance

The optical design of an optical instrument is often less than half of the design work. The mechanical design of the elements and their support and positioning are also at least as critical. If we look at the typical astronomical telescope consisting of two or three mirrors, there are many more parts in the mechanical structure that support and position the mirrors and attempt to do so without distorting the functional surfaces. It can be seen that the mechanical design or the optomechanics plays a major role in any optical instrument development, particularly where the optics and mechanics interface.

It can be seen from the examples of the HST and eyeglasses given earlier that optomechanics is significant to our lives over the whole gamut from the mundane to the sublime. An out-of-tolerance condition in our glasses can cause us headaches and other discomfort. A similar condition in the HST caused the scientific community emotional and fiscal pain. On the other hand, proper eyeglasses enhance our individual abilities and comfort, and a proper HST has expanded our knowledge of the universe. The reader’s own imagination can provide a myriad of other examples of the role and significance of optomechanical design. These might include adjustable rearview mirrors in cars or very sophisticated military optical systems for targeting and surveillance applications.

The optical and mechanical designers of instruments have by far the greatest influence on the ultimate cost and performance of an instrument. All other disciplines, including manufacturing operations, cannot have as much influence as the designers to change the potential satisfaction of the user and profitability of the producer. Therefore, once the instrument’s function is satisfied, affordability is of great significance in optomechanical design. Figures 1.1 and 1.2 illustrate these effects and show some of the typical steps in the process of developing an optical instrument.

Figure 1.1Overall process to develop and produce a new optical product.

Figure 1.2Detail design and analysis process of an optical product.

1.2Geometric Optics Fundamentals

1.2.1Basic Terminology

In this section, we will discuss some of the more pertinent optical terms and definitions which are often needed by the optomechanical design engineer. These terms will be highlighted in italic where they first occur in the following discussion. There are many good texts such as Smith’s study1 for more details, if nee...

Table of contents

• Cover
• Half Title Page
• Title Page
• Copyright Page
• In Memory Of
• Dedication
• Contents
• Foreword
• Preface
• Editors
• Contributors
• Chapter 1 Optomechanical Engineering Basics
• Chapter 2 Optomechanical Design Principles
• Chapter 3 Materials for Optical Systems
• Chapter 4 Mirror Materials
• Chapter 5 Plastic Optics
• Chapter 6 Lightweight Mirror Design
• Chapter 7 Optomechanical Tolerancing and Error Budgets
• Chapter 8 Optical Mounts Lenses, Windows, Small Mirrors, and Prisms
• Chapter 9 Adjustment Mechanisms
• Chapter 10 Analysis and Design of Flexures
• Chapter 11 Optomechanical Constraint Equations
• Chapter 12 Structural Analysis of Optics
• Chapter 13 Thermal Analysis of Optics
• Chapter 14 Fabrication Methods
• Index