During the design of a complex optical system one aspect which is often overlooked is how the system is to be built. Too often a paper design is created by one engineering group while producibility is left to another. In this paper it is shown how with very little extra cost it is possible to minimize assembly and alignment difficulties.

The optical design of a multi-channel sight for use in an armoured vehicle used in an air defense role, is described. Emphasis is laced on the interaction and conflicts among the various optical channels and the resolution of conflicting requirements.

This paper discusses the design and development of the Image Transfer Assembly (ITA) which allows integration of the TOW antitank missile weapon system with the Ml 13 armored personnel carrier to achieve the Improved TOW Vehicle (ITV). The discussion includes a brief description of the TOW weapon system, the need to incorporate it into an armored vehicle, the design options for implementing the integration and the major influencing factors that led to the final specific system configuration. The complete 1TA system is presented, describing the optomechanical configuration, stating the pertinent optical system characteristics, and highlighting the major problem areas attendant to the development program.

A growing market for thermal imaging systems has led to a demand for various new types of high performance refractor telescopes. Many system applications impose space constraints which require telescopes with a short overall length and minimum objective aperture oversize. By using high order aspheric surfaces and optical materials other than germanium it is possible to produce telescope designs which are compact and offer other attractive features. One such telescope design is described in detail, the emphasis being placed on the optical design and its effects on different system configurations.

In modern optical systems precise lens centering requirements must be achieved to minimize non-symmetrical aberrations. In this paper, several traditional and unique methods and their application of optical element centering in fabrication and assembly are presented and analyzed.

The performance goals of the Advanced X-ray Astrophysics Facility (AXAF) require that the Wolter I optics support system be insensitive to temperature fluctuations and the effects of gravity during ground testing. Previous work has shown that acceptable concepts are achievable but require much attention to design details. This paper discusses a new support system wherein each optic is held by a single circumferential ring near its center of mass rather than a multipoint support as previously analyzed. The thermal sensitivity of this system is considerably lower than any concept yet studied. This advanced support concept allows the use of a wider variety of materials and simple design details. Structural analysis utilizing the finite element method and optical ray-trace analysis are used to predict the system performance.

The traditional approach to design of baffles for suppressing stray radiation uses a tube lined with black diffuse baffles to eliminate single-scatter paths to the primary optics. However, the black baffles can absorb an excessive amount of heat and contribute to increased background radiation at infrared wavelengths if used in proximity to relatively intense off-axis radiation sources, such as the sun in some sensor applications or the earth itself in other applications. This paper describes a baffle tube design using reflective baffles of elliptical cross section. The design rejects most of the load, but intrinsic limitations allow some skew rays to land on surfaces facing the primary, resulting in increased scatter. The benefits of decreased aperture load must be carefully weighed against increases in background due to scatter. Fabrication tolerances must also be considered, because they will degrade performance. This paper addresses these tradeoffs and describes some analysis methods for evaluating specular baffle designs.

Interferometry provides opticians and lens designers with the ability to evaluate optical components and systems quantitatively. A variety of interferometers and interferometric test procedures have evolved over the past several decades. This evolution has stimulated an ever-increasing amount of interest in using a new generation of instrumentation and computer software for solving cost and schedule problems both in the shop and at field test sites. Optical engineers and their customers continue to gain confidence in their abilities to perform several operations such as assure component quality, analyze and optimize lens assemblies, and accurately predict end-item performance. In this paper, a set of typical test situations are addressed and some standard instrumentation is described, as a means of illustrating the special advantages of interferometric testing. Emphasis will be placed on the proper application of currently available hardware and some of the latest proven techniques.

Pilkington P. E. were asked to develop a 300 mm. aperture, high-precision scanning interferometer with associated software for the semi-automatic testing of far infrared lenses and systems. The instrument as developed is capable of analysing and evaluating systems in terms of OTF, PSF, wavefront aberration, ray intersection patterns, polynomial fitting, aberration contouring, refractive index variation mapping and of providing a large range of representations of data. The speed of the analysis is commensurate with established techniques with an improvement in the accuracy and flexibility of use of the instrument over alternative measuring systems. Results from the developed system will be presented to show the effectiveness of the instrument.

The advantages of Phase Measuring Interferometry (PMI) over conventional half-wave fringe contour measurements are well known. They include greater sensitivity through reduced fringe-to-fringe interval, ease of minimizing instrumental errors, shorter turnaround time to process results and data averaging to circumvent random environmental effects. Prior publications have described typical designs of PMI devices as well as some of their applications in the optical industry. At Perkin-Elmer, we have found that only through the use of advanced PMI technology can quantity production of very high quality optics be achieved on a timely and cost-effective basis. In this paper, we report some experiences with PMI as the primary method of in-process and final testing of a variety of optical components currently being manufactured in production quantity. Component apertures are as large as 47 cm. Measurements are typically made to precisions of the order of 0.01k (X/100) peak-to-peak and 0.001λ (λ/1000) rms. Examples include three types of reflecting optics of widely differing sizes and configurations: an Amici-type roof mirror, a concave spherical mirror and a convex spherical mirror.

Precision scanning of fringes between a concave test plate and a convex aspheric mirror brought the mirror from a sphere to within λ/4 of its final figure. This was achieved while maintaining control of the vertex radius. Description of hardware and data reduction techniques will be presented.

The influence of polishing time on the surface structure of optical elements is shown for germanium lenses. The surface structure is measured with a profilometer and expressed in the form of CLA values. Veiling glare of single lenses manufactured under different conditions is measured in the infrared spectral region (IR) between 3 and 10 μm. An instrument to measure the relative veiling glare ratio in the IR is shown. The results are discussed. The image quality of these lenses is shown as fine-line images and MTF measure-ments. An imperfect surface structure affects more greatly the shorter spectral region. The results are interpreted. Roughness of single point diamond turned lenses are compared with optically polished lenses.

The Optical Angle Marker is a double mirror device, consisting of two first surface flats, and is used together with an autocollimator. The two mirrors are aligned with their faces nearly parallel. When the mirror assembly is rotated in azimuth relative to the autocollimator, a series of return images, spaced at equal angular intervals, can be viewed. In this way, the angular range of an autocollimator may be extended by a factor of six or more, depending on size and quality of the flat mirrors. Experimental data is described in this paper.

The develoment of the specified optical system parameters is followed from initial constraints, recuirements, and scenarios. The process includes consulting with the optical designers, to keep the design practical and performing analyses, to define the system configuration, such as amortioning apertures and spectral bands. The fire control system consists, of two sighting systems, a search sensor called the Squad Leader's, Periscope and a tracking system with integral laser rangefinder called. the. Gunner's Sight. Both systems are stabilized and have a night vision capability.

In the design of military optical systems there frequently exists conflicts among requirements for high performance or precision, size and weight, and the ability to withstand harsh environments. The AN/GVS-5 Hand Held Laser Rangefinder developed for the U.S. Army is a good example of such a system comprising precise alignment of three optical axes in a five pound, field deployed equipment. Final success of the program was the result of innovative design, careful material selection, and attention to detail in manufacture and process control.

The conventional or direct detection Bragg Cell Spectrum Analyzer, or simply Bragg Cell receiver (Figure 1), is useful in defense related applications, the reason being that real time spectral analysis of RF signals is an important element of electronic warfare and surveillance. For such applications, wide bandwidth (up to 1 GHz) and high frequency resolu-tion (≈1 MHz) are desirable features and they have indeed been exhibited by experimental Bragg Cell receivers. Wide dynamic range, eg, 50 to 60 dB, is yet another matter. To date, achievable dynamic range has probably been about 30 dB, or perhaps even 40 dB. To understand the source of the dynamic range limitation and also to set the stage for the new receiver architecture which will be discussed, we will first review some Bragg Cell receiver principles.

Three separate but precisely-aligned radiation paths are incorporated in the monolithic Laser Rangefinder Telescope Assembly (LRTA) projector head: a high-power IR laser, an IR receiver and a visual reticle projector. The design problems fell mainly into three categories: outgoing laser radiation confinement, alignment accuracy and per unit cost (manufacturability). The reasons for the selection of the optical design, coatings and materials are discussed to illustrate the emergence of a reproducible component from a working prototype.

For more than 15 years, NASA, the National Academy of Sciences, the America Institute of Aeronautics and Astronautics, and the community of the world's astronomers vigorously promoted the idea of a telescope in space, at seminars, symposia and conferences. Follow-ing several years of detailed engineering design studies, Congress in 1977 gave approval for a 2.4-meter Space Telescope to be designed, developed and launched from the Space Shuttle, which itself at that time was in the early stages of development. Following a competition, contracts were awarded to Lockheed for the Spacecraft and to Perkin-Elmer for the Optical Telescope Assembly.