Achromatic lens invented by johan dollond in year 1758. By applying this strategy, i reached successful solutions that used only six glassesthree glasses for the achromatic design and three additional glasses for the apochromatic design. Apochromatic refractor apo telescopes telescopes, solar. Jan 09, 20 apochromatic is an ideal that no physical lens is likely to achieve. The achromatic lenses originally designed for telescopes can now be found in various optical instruments, including cameras. Apochromatic vs achromatic refractors cloudy nights. Apochromatic vs achromatic refractor people should think twice before purchasing an apochromatic refractor as opposed to an achromatic telescope. The latest development is the superachromat, which is corrected for four colors. When the designers at explore scientific set their sights on creating a topquality essential ed80 80mm airspaced triplet apochromatic refractor that anyone would be proud to own, they decided on a traditional airspaced triplet optical design in a rugged, adjustable lens cell. Our method separates an apochromat into two achromatic objectives, which have secondary spectra that cancel and separate fourcrossing superachromats as two apochromats, which have tertiary spectra that cancel. Thorlabs super apochromatic microscope objectives provide axial color correction in the visible range and a flat field of focus in a variety of imaging modalities without introducing vignetting. Optical glass compatibility for the design of apochromatic. In this paper, the major qualifications were first proposed to design the collimator objective lens,according to which the initial configuration was confirmed.
Common microscope objective lenses include achromatic, plan achromatic, fluorite, plan fluorite, apochromatic and plan apochromatic lens. Modern lens design mcgrawhill professional engineering. Apochromatic designs of lens systems utilizing two optical materials are. An apo or apochromatic lens isusually an anonymous design feature.
With modern lens design and careful choice of lens materials, combined lens. At shanghai optics, we design and manufacture highquality precision achromatic lenses to unique specifications. The main determining factors for choosing lenses includes the number of fluorescence colors you may want to detect, the quality of images required, and the working distance distance between sample and the lens. Explore scientific instruction booklet for triplet refractors the explore scientific 102mm f7 airspaced triplet ed apo telescope made wired magazines wish list for cool gifts and is a perfect instrument for demanding wide field observing and astrophotography. Used explore scientific ed80 80mm airspaced triplet. Pdf design of achromatic and apochromatic plastic micro. A fundamental problem with camera optics is that the light that forms the image on the film or sensor comprises a range of wavelengths. Design of twoglass for apochromatic optical system raghad ismail ibrahim almustansiryah universitycollege of educationphysics department, baghdad, iraq, abstract. The 80mm airspaced doublet lens is crafted with one element of fpl53 extralow dispersion, ed, optical glass, which virtually eliminates the effects of chromatic aberration. Oct 08, 2012 hii have read the technical diference between these two types of refractor, but do you think the difference would be noticeable to a beginneruntrained eye. A method of glass selection for apochromatic optical systems with reduced chromatic aberration is present. Design of achromatic and apochromatic plastic microobjectives. This is due to the regular structure of red, green and blue pixels on the sensor e. I am proud of nikon, who appears reluctant to label a lens apochromatic just because they used low or anomalous dispersion rare earth glasses to reduce its chromatic aberrations.
This new method makes it possible to select sets of compatible glasses suitable for the design of superapochromatic optical systems. Revised 6292003 i hope the following history of the apochromatic lens designs made by roland christen of astrophysics is of some interest to the readers. Apochromatic designs of lens systems utilizing two optical materials are described. With modern lens design and careful choice of lens materials, combined lens systems can be designed to offset the dispersion. Achromatic lenses are ideal for a range of applications, including fluorescence microscopy, image relay, inspection, or spectroscopy. However, a very large amount of residual color aberration known as secondary spectrum still remains. See our options for building your own lens, or request a quote to see how s. These elements are able to focus different wave lengths of one light ray in one point see picture below. The design requirements for a nonfluorite material apochromatic objective lens with a large field and high definition for machine vision detection have been achieved. So designing a large field of view, apochromatic collimator objective lens has an important practical significance.
These are simply not necessary for a book on lens design. An achromatic lens, which is often designed by either cementing two elements together or mounting the two elements in a housing, creates smaller spot sizes than comparable singlet lenses. I love color correcting refractive optical systems. What is teh difference between an apochromatic and achromatic lensescope. Apochromatic objectives are constructed by combining three lenses made of different materials with properly chosen powers and dispersions. Malacara, hand book of optical design, 3th edition, usa. The handbook of optics, from the optical society of america, is a tremendously valuable resource for all optics practitioners each chapter is a great introduction for a specific optics subspecialti. In a singlelens setup, blue light is focussed closer to the lens and it has a shorter focal length. Corrected for both chromatic and spherical aberration, as a lens. Ed glass both achromatic and apochromatic lenses often contain at least one element that uses a special lowdispersion glass. Even though there has been much progress in optical design software since the book was written, the principles are timeless. Subsequently, the new glasses would demonstrate their value in correcting astigmatism, and in the production of achromatic and apochromatic lenses.
The apochromat this lesson shows how to design a lens with better color correction than one can get with a simple doublet. They are very readable and include a lot of information on the design of specific lens types not found elsewhere, for example, complex apochromatic lenses in the second volume. These objectives are designed for use with a tube lens focal length of 200 mm and have optical elements that are arcoated for improved transmission. Design of twoglass for apochromatic optical system raghad. Achromatic and athermal lenses chapter 7 introduction to lens. Apochromatic collimator objective lens design with big field. There is a huge difference in price and a small difference in performance according to an experiment i made recently. Apochromatic optical systems need a specific combination of optical glass sorts, whose dispersive properties insure correction of the longitudinal chromatic aberration and secondary spectrum.
The introduction of the computer revolutionized the way lenses optical systems are designed and evaluated. What is apo and what are the real apo lenses on the market. An achromatic lens or achromat is a lens that is designed to limit the effects of chromatic and spherical aberration. This method is based on the glass maps by using a glass database schott glass and an optical design program oslo to help the optical designer to select optical. Our method relies on the ability of lens design programs to plot the chromatic focal. Achromatic and apochromatic refractor designs starizona. Practical computeraided lens design by gregory hallock smith. An apochromatic telescope has a multilens setup to eliminate chromatic aberration when stargazing. An apochromat, or apochromatic lens apo, is a photographic or other lens that has better. Apochromatic triplet lenses are as the name suggests, a compound lens with three lens elements that are designed to achieve the same focal length for three wavelengths of light.
Criteria for color correction derived from the dispersion formulas of hartmann, cauchy, schmidt, conrady, and buchdahl will be discussed, and their application to. The simplest way to reduce chromatic aberration is to increase the focal length of the lens system whenever possible, so the effect is less prominent in relation to the image location. These books are the basis for a two semester graduate course in lens design. Aug 01, 2016 design of apochromatic lens with large field and high definition for machine vision. Also, im looking at this beauty, because it is near my budget. Apochromatic is an ideal that no physical lens is likely to achieve. During this time optician george bass, following the instructions of chester moore hall, made and sold such lenses. Chromatic aberration is caused by the difference in wavelength of various colours of light. With locations and names of over 260 features on the moon such as craters, mountains, valleys, seas and more, the included orion moonmap 260 is a great tool for beginning astronomers. Manufacturers label lenses as apo according to their own standards, or with many i suspect when they have made more attempt than usual at correction or more cynically as a suffix used in marketing. Precise machine vision detection for a large object at a finite working distance wd requires that the lens has a high resolution for a large field of view fov. Introduction to lens design by jose sasian september 2019. Orion observer 80st 80mm equatorial refractor telescope kit.
Method to design apochromat and superachromat objectives. An apochromat, or apochromatic lens apo, is a photographic or other lens that has better correction of chromatic and spherical aberration than the much more common achromat lenses. Apochromatic designs require optical glasses with special dispersive. Apochromatic lens definition of apochromatic lens by. The normal configuration is a positive, lowdispersion crown, combined with two highdispersion flints, one negative and one positive. Achromatic lens is used to minimize or eliminate chromatic aberration. Design of apochromatic lens with large field and high definition for machine vision. However john dollond, an english optician, was the first person to patent the achromatic lens in 1758. The optical glass manufacturers offer a wide range of.
Pdf the possibility and the efficiency of using a single diffractive lens to achromatize and apochromatize microobjectives with plastic lenses are. Aug 31, 2011 it is basicaly impossible to make an apochromatic lens of any kind that is faster than f5ish with even the most modern optical glasses. Method of glass selection for color correction in optical system design. Apochromatic definition of apochromatic by the free dictionary. Hii have read the technical diference between these two types of refractor, but do you think the difference would be noticeable to a beginneruntrained eye. This paper presents a novel approach to the design of such apochromatic combinations which automatically minimizes the residual chromatic aberration over a specific wavelength range. Would a 80mm apo give some super crisp contrasty wide field views that maybe a 120mm achromatic may. Michael kidger, fundamental optical design and intermediate optical design. Conventional periscope optical design has traditionally employed common achromat relay and objective lenses to correct color aberrations. Osa design of apochromatic lens with large field and high.
Apochromatic vs achromatic refractor computer physics lab. It is basicaly impossible to make an apochromatic lens of any kind that is faster than f5ish with even the most modern optical glasses. A method of glass selection for apochromatic optical systems with reduced. Today, an outstanding degree of correction of the chromatic aberrations of a lens is even more important than in the analogue era of photography. Detailing design methods for a variety of lens forms, this book shows that fixed focus and zoom lenses can be optimized, starting from planeparallel surfaces, in a brief time on a. The computer program oslo was used to design the work, but the writeups are programneutral. The design of apochromatic systems is difficult because of two problems. The origin of achromatic lens can be traced back to 1733. Precise machine vision detection for a large object at a finite working distance wd requires that the lens has a. Book depository books with free delivery worldwide.
The art and science of optical design by robert shannon 1997 page 191 and you will see that these lenses are clearly not apochromatic. The strict definition of apochromatism is having three wavelengths of light focusing to the same point. The glasses that are needed to make the lens apochromatic are combined into triplet correctors with two buried surfaces. Criteria for color correction derived from the dispersion formulas of hartmann, cauchy, schmidt, conrady, and buchdahl will be discussed, and their application to the design of apochromatic optical systems will be presented. The chromatic focal shift for an achromatic doublet made out for bk7 and f2. The design of achromatic also helps minimize spherical aberrations. I recently published an article in the journal applied optics where i describe a very fast method for selecting optical glasses for the design of an apochromatic lens with a large field of view 1. A world leader in the manufacturing of telescopes, solar telescopes, microscopes, optics, binoculars, for amateur astronomers and hobbyists.
Therefore, this book can be used with any lens design software. This normally requires a third lens element in the objective. Abbe started the design of a photographic lens of symmetrical design with five elements, but went no further. The orion moonmap 260 makes it easy to locate and learn about interesting features on the moon. So the eon 80ed apochromatic refractor telescope gives you brighter images, a wider field of view, and allows shorter exposures of deepsky objects.
Would a 80mm apo give some super crisp contrasty wide field views that maybe a 120mm achromatic may miss and while the latter will have more. Apochromatic refractors, optics, astronomical equipment and techniques. Design of apochromatic lens with large field and high. Oct 14, 2010 apochromatic vs achromatic refractor people should think twice before purchasing an apochromatic refractor as opposed to an achromatic telescope. Explore scientific 102mm f7 ed apochromatic triplet.
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