Book contents
- Frontmatter
- Contents
- Preface
- Symbols, signs and other conventions
- Part I General theory
- 1 Introduction
- 2 Image formation and ray tracing
- 3 Paraxial theory of refracting systems
- 4 Paraxial theory of reflecting optics
- 5 Non-Gaussian optics: Introduction to aberrations
- 6 Simple lens types, lens systems and image formation
- 7 Mirror types and image formation
- 8 Prisms
- 9 Aperture stops and pupils, field lenses and stops
- 10 Defocus, depth-of-field and focussing techniques
- 11 Basic optical metrology
- 12 Photometry of optical systems
- Part II Geometrical optical instruments or systems
- Part III Physical optics and physical optical instruments
- Part IV Ophthalmic instruments
- Part V Aberrations and image quality
- Part VI Visual ergonomics
- Appendices
- Index
11 - Basic optical metrology
Published online by Cambridge University Press: 13 January 2010
- Frontmatter
- Contents
- Preface
- Symbols, signs and other conventions
- Part I General theory
- 1 Introduction
- 2 Image formation and ray tracing
- 3 Paraxial theory of refracting systems
- 4 Paraxial theory of reflecting optics
- 5 Non-Gaussian optics: Introduction to aberrations
- 6 Simple lens types, lens systems and image formation
- 7 Mirror types and image formation
- 8 Prisms
- 9 Aperture stops and pupils, field lenses and stops
- 10 Defocus, depth-of-field and focussing techniques
- 11 Basic optical metrology
- 12 Photometry of optical systems
- Part II Geometrical optical instruments or systems
- Part III Physical optics and physical optical instruments
- Part IV Ophthalmic instruments
- Part V Aberrations and image quality
- Part VI Visual ergonomics
- Appendices
- Index
Summary
Introduction
It is sometimes necessary to determine the structural properties of a single lens or lens system. This information may be needed to understand the optical properties which can be further investigated by ray tracing. For example, we can use the knowledge of the refractive indices, surface curvatures and surface separations to determine the Gaussian properties such as the powers and positions of the cardinal points by paraxial ray tracing, using techniques described in Chapter 3. The ray trace results can also be used to calculate the primary or Seidel aberrations using the equations given in Chapter 33. The powers and cardinal points can also be measured directly by laboratory techniques without the need to take the system apart.
Thus this chapter is concerned with the analysis of optical systems that have been constructed and for which we do not have the constructional details. That is we do not know the refractive indices of the materials, the surface separations or the surface curvatures. If we wish to examine the optical properties of such a system, we can solve the problem in two ways.
(1) We can take the system apart, measure the refractive indices, surface separations and surface curvatures. Using paraxial ray tracing, we can determine the Gaussian properties such as equivalent power and positions of the cardinal points.
(2) We can measure the Gaussian properties directly. For example, in this chapter we will describe several methods for measuring the equivalent power of an optical system in the laboratory.
The powers and cardinal point positions are not the only Gaussian parameters that occasionally have to be verified.
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- The Eye and Visual Optical Instruments , pp. 245 - 270Publisher: Cambridge University PressPrint publication year: 1997