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Topic: Achromatic lens

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	Achromatic lens system including a diffraction lens - Patent 5959785
		achromatic correction of light in the visible region is conducted by correcting said axial chromatic aberrations with a diffracting function of said diffraction lens.
		The achromatic lens system according to claim 3, wherein the second positive lens element of said front lens group is cemented to said negative lens element of said front lens group.
		In the lens system according to the present invention, the frontmost and rearmost surfaces of the front lens group 11 on the object side and the image side are respectively made of a convex surface and a concave surface.
	www.freepatentsonline.com /5959785.html (5075 words)

	ARRI Lens Tutorial - What is an Achromatic Lens Assembly? (Site not responding. Last check: 2007-11-05)
		Achromatic assemblies are particularly good at compensating for chromatic aberration, an optical effect that can be seen as color fringing in the image, usually at high contrast edges.
		When a beam of light passes through a single lens, the different colors are bend at different angles based on their wavelengths (called dispersion), and the lens will focus the different colors at different points.
		The crown lens performs the desired optical effect (for example magnifying an image) and introduces some dispersion, and the flint lens aims at balancing this dispersion while having the least possible optical influence itself.
	www.arri.com /prod/cam/tutorials/achromatic/achromatic.html (264 words)

	I. R. Poyser Telescopes - Glossary of Common Astronomical
		Achromatic lens A lens that is designed to produce a view or image that is free of the fringe of rainbow colours that surrounds the images produced by simpler lenses.
		It is the eyepiece lens that is nearest to the objective lens or the primary mirror.
		For example, a lens with a focal length of 60cm and a diameter of 4cm has a focal ratio of f/15, because 60cm divided by 4cm is 15.
	www.irpoyser.co.uk /glossary.php (2172 words)

	Microscope-Depot.com Glossary of Terms Page
		Achromatic lens: a lens specially designed and coated to correct for the tendency of light to separate into colors when passing through glass.
		Doublet lens: a lens design that is actually two different lenses cemented together (usually one positive magnifier and one negative).
		Objective lens: The lens in a microscope closest to the specimen.
	www.microscope-depot.com /glossary.asp (1574 words)

	Reflected Ultraviolet Photography - Optical considerations
		In practice the lens manufacturer uses these two glasses in such a manner that equal and opposite amounts of chromatic aberration are induced allowing most of the visible spectrum to be sharply focussed at one 'compromise' point.
		Thus, an inspection of the curves shows that with a modern multi-element achromatic lens, the ultraviolet may focus at approximately the same plane of focus as the infrared whereas with the apochromat the infrared and ultraviolet focus shifts will be in opposite directions.
		The lens elements are manufactured from fluorite and quartz, and this allows a spectral transmission as high as 70% from 300nm to 900nm (Figure 40).
	msp.rmit.edu.au /Article_01/07.html (1842 words)

	Achromatic lens and zoom lens using the same - US Patent 6490096 (Site not responding. Last check: 2007-11-05)
		In a zoom lens comprising first to fourth lens groups, the second lens group comprises two meniscus lenses and an achromatic lens.
		The achromatic lens comprises a cemented lens having a negative refracting power as a whole, and a lens having a positive refracting power with a convex surface directed onto the object side.
		The cemented lens comprises a meniscus lens or plane-convex lens having a positive refracting power with a concave surface or plane directed onto the object side, and a lens having a negative refracting power.
	www.patentstorm.us /patents/6490096.html (187 words)

	Definitions
		The lower lens may be used to focus the illumination between the elements so that it emerges from the stationary lens as a large diameter parallel bundle.
		In a lens system, such as a micro-scope with its lamp, an aperture diaphram is one that is imaged in the objective aperture and limits the angular extent of the illumination beam.
		An achromatic doublet may be composed of a positive crown-glass lens and a negative flint-glass lens.
	www.nationalmicroscope.com /definitions.html (10287 words)

	Glossary Terms: A
		A simple aspheric lens is widely used as a lamp condenser because of its efficiency in converging lightrays to one focal plane.
		A defect in a lens or optical system which causes rays in one plane parallel to the optical axis to focus at a distance different from those in the plane at right angles to it.
		One of several imaginary lines assumed in describing the positions of the planes by which a crystal is bounded, the positions of the atoms in the structure of the crystal and the directions associated with vectorial and tensorial physical properties.
	www.charfac.umn.edu /glossary/a.html (2550 words)

	Achromatic Lens - Doublets
		Achromatic doublet lenses have significantly better optical performance than singlet lenses in visible imaging and laser beam manipulation applications.
		Achromatic Lenses are consist of two elements, usually of a positive low-index crown glass cemented to a negative high-index flint glass that have been corrected for chromatic aberration with respect to two selected wavelengths in the blue and red region of the spectrum.
		One frequent use of Achromatic Lens is to achieve diffraction limited focusing of a laser beam.
	www.achromaticlens.com (226 words)

	Achromatic Lens Kits
		For applications where multiple focal length doublet lenses may be needed, achromatic lens kits provide a convenient selection of equivalent diameter lenses from which to choose.
		Our achromatic lens kits are offered in one and two inch diameters.
		Achromatic lens kits are offered with broadband visible Anti-Reflection coatings to minimize ghost reflections and losses.
	www.laser2000.co.uk /os/amatlens.htm (117 words)

	Sphæra issue no. 8: article 5 (Site not responding. Last check: 2007-11-05)
		It is the original manuscript of the rebuttal prepared by Peter Dollond to Jesse Ramsden's charge that John Dollond took the idea of the achromatic telescope from the previous work of Chester Moor Hall, having learnt of it through an encounter with the optician George Bass.
		John Dollond's famous paper on achromatic combinations of lenses was read at the Royal Society in June 1758 and published in the Philosophical Transactions the same year.
		Ramsden's paper was King's source for the account of Hall ordering crown and flint components for an achromatic doublet separately from Edward Scarlett and James Mann, and of each of them independently sub-contracting their order to George Bass, who was thus able to discover the secret.
	www.mhs.ox.ac.uk /sphaera/issue8/articl5.htm (2044 words)

	Peak Optics Online
		Achromatic lenses are corrected for two colors and produce flatter fields of view at higher powers.
		Achromatic lenses correct this problem by focusing many colors at the same point.
		Several factors to remember with these loupes are that as the magnification increases, the lens diameter generally decreases, as the magnification increases the working distance between the lens and the subject decreases and as the magnification increases the flat, field-of-view decreases.
	www.peakoptics.com /definitions.php (964 words)

	Achromatic doublet lens (Site not responding. Last check: 2007-11-05)
		Achromatic doublet lenses ("achromat") are designed to eliminate chromatic and spherical aberrations inherent in singlet lenses.
		When used on-axis, an achromatic lens focuses an parallel input beam to a perfect "point", limited only by the effects of diffraction.
		For some applications it is desirable to have a high-quality lens with a lower f/# (for example, collimating a diode laser with large divergence angle).
	www.optics-online.com /ach.asp (259 words)

	Technical information page
		When using film cameras it is usual to express the magnification obtained by a lens in terms of the size of the image on the film.
		On 35mm film the image size is 36x24mm, so a life-size image (1:1 magnification) will be obtained if the camera lens can be focused on a subject of dimensions 36x24mm so that the image fills the viewfinder frame and so occupies all the image area on the film.
		The Olympus specifications state that the camera lens, with its 7-70mm zoom is the equivalent to a 38-380mm zoom on a 35mm camera.
	www.mybitoftheplanet.com /tech/macrodims.html (744 words)

	A Simple DIY Stereoscopic Microscope
		Mount the compact binoculars on the achromatic lens, and by makeshift means, clasp them at a height which allows you to clearly see the minute writing placed on the table.
		The height of the achromatic lens must be equal to X - h, where 'h' is the height of the compact binoculars.
		Measure the distance from the lens center to the lamp (distance A), and the distance from the lens center to the screen (distance B).
	www.funsci.com /fun3_en/uster2/uster2.htm (4407 words)

	Achromatic lens - National Maritime Museum (Site not responding. Last check: 2007-11-05)
		An achromatic lens produces images free from chromatic aberration – the appearance of coloured fringes around the object viewed.
		Achromatic lenses are constructed using a combination of at least two lenses made of different types of glass.
		The introduction of achromatic lenses allowed telescopes to have shorter focal lengths.
	www.nmm.ac.uk /collections/explore/index.cfm/category/90128 (97 words)

	Museo della Specola, Bologna - Catalogue, telescopes, 37 (Site not responding. Last check: 2007-11-05)
		In reply to Euler’s suggestion in 1747 that achromatic object lenses could be made using different types of glass pastes, John Dollond (1706-1761) pointed to Newton’s demonstrations that such lenses were not possible, and began corresponding with Euler on this score.
		Made with a concave flint-glass lens and a convex crown-glass lens, it had a focal length of 5 feet (c.
		Fitted with a top quality achromatic object lens, this telescope is part of the instruments bought by Petronio Matteucci - director of the Specola after the death of Zanotti in 1782 - to renew the equipment which was still basically the English instruments by Sisson of the first half of the century [files 38-41].
	www.bo.astro.it /dip/Museum/english/can_37.html (624 words)

	refracting telescopes, refractors achromatic apochromatic astronomy
		This is where the curvature of the lens causes differences in distance between the center of the lens to the focus point, and the outer edges of the lens to the focus point, once again giving a poor image.
		This system of gluing the lenses together is called an achromatic lens, hence the name achromatic refracting telescope.
		Apos, as they are known, use multiple elements (up to four) in their main lens made form extra low dispersion (ED) glass and/or fluorite.
	www.telescopes-astronomy.com.au /telescopes013.htm (419 words)

	Achromatic Lens
		Achromatic Lenses consist of two or more elements, usually of crown and flint glass that have been corrected for chromatic aberration with respect to two selected wavelengths.
		Red Optronics provides achromatic lenses consisting of two elements.
		The minimum diameter of Achromatic Lens we can process is 3.5mm.
	www.redoptronics.com /achromatic-lenses.html (87 words)

	achromatic lens - Search Results - MSN Encarta
		- lens with reduced distortion: a composite lens in which two or more lenses with different properties are combined to prevent distortion chromatic aberration
		Lens (optics), in optical systems, glass or other transparent substance so shaped that it will refract the light from any object and form a real or...
		Search for books about your topic, "achromatic lens"
	encarta.msn.com /achromatic_lens.html (105 words)

	Refracting Telescope :
		Its 45mm achromatic lens gives you sharp, crisp images and combinations of 2 eyepieces and Barlow lens gives you a maximum magnification of 80x.
		Its gigantic 150mm Achromatic objective lens gulp in the light gathering that images which are dim and obscure in smaller scopes appears bold and distinct.
		It is a simple concave (negative) lens or doublet that increases the instrument's effective focal length boosting the magnifying power of any eyepieces.
	www.galileotelescope.com /nf/indrfr.htm (2760 words)

	achromatic lens concept from the Astronomy knowledge base (Site not responding. Last check: 2007-11-05)
		achromatic lens concept from the Astronomy knowledge base
		has definition Lens (or combination of lenses) that brings different wavelenghts within a ray of light to a single focus, thus overcoming chromatic aberration.
		achromatic objective (2 facts) - A lens of two or more components with different refraction indices (e.g., crown glass and flint glass), used to correct for chromatic aberration.
	www.site.uottawa.ca:4321 /astronomy/achromaticlens.html (108 words)

	The Digital Video Information Network - Close-up achromatic lens for FX1
		June 29th, 2005 06:24 AM Seems like we need 250D for FX1, judging by the specs: 250D is for 30-135mm focal length of the lens, while 500D is for 70-300mm.
		June 29th, 2005 10:58 AM 52mm or 58mm is quite a step-down, especially for a lens as wide-angle as the FX1.
		If you're planning on always being zoomed in 100%, then that shouldn't matter, but if you wanted to be able to use more of the focal range of the lens, just be aware that you'll be losing a significant amount of range.
	www.dvinfo.net /conf/printthread.php?t=46889 (678 words)

	telescope-india.com / Astronomical Mirror / Optical Flat / Achromatic Lens ( Achromatic Objective)
		Parabolic astronomical mirrors are polished and figured to yield high level performance.
		High power - offer finally matched 2 - element high quality achromatic objective, each lenses are guaranteed to be colour corrected and free of spherical aberrations of less than 1/4 wave-front error.
		Each surface is individually inspected and corrected during process of manufacturing than tested and certified as an achromatic of high order.
	www.tejraj.com /optics.html (435 words)

	Achromatic, meniscus lens pair
		Adding an aplanatic meniscus lens to an achromatic lens can increase relative aperture without introducing additional spherical aberration.
		Achromatic lens and meniscus lens pairs are often used in diode laser collimators.
		Achromatic doublet and mensicus lens pair, D=15, EFL=33
	www.optics-online.com /acp.asp (237 words)

	Achromatic lens (Site not responding. Last check: 2007-11-05)
		This is not how achromatic lenses are really made, but it will give you an idea of how the general problem is attacked.
		We use the simple lensmaker formulae for power P=1/f=(n-1)/r and "powers add" for closely spaced lenses and simplify further by making a plano convex lens out of blank 1 and a plano concave lens out of blank 2.
		P=2/3 for both blue and red, we made a f=1.5 metre achromatic lens!
	www.physics.uq.edu.au /people/ross/phys2081/instr/achromat.htm (320 words)

	Amazon.com: Zhumell 2x Achromatic Barlow Lens: Camera & Photo (Site not responding. Last check: 2007-11-05)
		2x Achromatic Barlow doubles the magnifying power of any eyepiece used in conjunction with it.
		The achromatic optical system provides you with excellent contrast and accurate color transmission.
		The Zhumell 1.25-inch, 2X, achromatic Barlow is a great way to improve your eyepiece collection.
	www.amazon.com /Zhumell-2x-Achromatic-Barlow-Lens/dp/B0002VKWPU (452 words)

	Close-up achromatic lens for FX1 - The Digital Video Information Network
		Canon makes two series, ones that are less-expensive single-element and ones that are more-expensive two-element achromats.
		Seems like we need 250D for FX1, judging by the specs: 250D is for 30-135mm focal length of the lens, while 500D is for 70-300mm.
		52mm or 58mm is quite a step-down, especially for a lens as wide-angle as the FX1.
	www.dvinfo.net /conf/showthread.php?p=328054 (698 words)

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