Knowledge (XXG)

Condenser (optics)

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106: 93: 278:), with a layer of immersion oil placed in contact with both the slide/coverslip and the lens of the condenser. An oil immersion condenser may typically have NA of up to 1.25. Without this oil layer, not only is maximum numerical aperture not realized, but the condenser may not be able to precisely focus light on the object. Condensers with a numerical aperture of 0.95 or less are designed to be used without oil or other fluid on the top lens and are termed dry condensers. Dual dry/immersion condensers are basically oil immersion condensers that can nonetheless focus light with the same degree of precision even without oil between the top lens and the slide. 149: 262:. In order for the maximum numerical aperture (and therefore resolution) of an objective lens to be realized, the numerical aperture of the condenser must be matched to the numerical aperture of the used objective. The technique most commonly used in microscopy to optimize the light pathway between the condenser (and other illumination components of the microscope) and the objective lens is known as 298:' that he understands the reasons for its efficiency. Makers in the 18th century such as Benjamin Martin, Adams and Jones understood the advantage of condensing the area of the light source to that of the area of the object on the stage. This was a simple plano-convex or bi-convex lens, or sometimes a combination of lenses. With the development of the modern achromatic objective in 1829, by 92: 105: 160:, who developed it in 1870. The Abbe condenser, which was originally designed for Zeiss, is mounted below the stage of the microscope. The condenser concentrates and controls the light that passes through the specimen prior to entering the objective. It has two controls, one which moves the Abbe condenser closer to or further from the stage, and another, the 67: 20: 207:
setups are based on an Abbe, aplanatic, or achromatic condenser, but to the light path add a dark field stop or various size phase rings. These additional elements are housed in various ways. In most modern microscope (ca. 1990s–), such elements are housed in sliders that fit into a slot between the
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This condenser is composed of two lenses, a plano-convex lens somewhat larger than a hemisphere and a large bi-convex lens serving as a collecting lens to the first. The focus of the first lens is traditionally about 2mm away from the plane face coinciding with the sample plane. A pinhole cap can be
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The Arlow-Abbe condenser is a modified Abbe condenser that replaces the iris diaphragm, filter holder, lamp and lamp optics with a small OLED or LCD digital display unit. The display unit allows for digitally synthesised filters for dark-field, Rheinberg, oblique and dynamic (constantly changing)
78:. They act to gather light from the microscope's light source and concentrate it into a cone of light that illuminates the specimen. The aperture and angle of the light cone must be adjusted (via the size of the diaphragm) for each different objective lens with different numerical apertures. 306:
ruled gratings. By the late 1840s, English makers such as Ross, Powell and Smith; all could supply highly corrected condensers on their best stands, with proper centring and focus. It is erroneously stated that these developments were purely empirical - no-one can design a good achromatic,
302:, the need for better condensers became increasingly apparent. By 1837, the use of the achromatic condenser was introduced in France, by Felix Dujardin, and Chevalier. English makers early took up this improvement, due to the obsession with resolving test objects such as diatoms and 85:
and one or more lenses. Light from the illumination source of the microscope passes through the diaphragm and is focused by the lens(es) onto the specimen. After passing through the specimen the light diverges into an inverted cone to fill the front lens of the objective.
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spherically corrected condenser relying only on empirics. On the Continent, in Germany, the corrected condenser was not considered either useful or essential, mainly due to a misunderstanding of the basic optical principles involved. Thus the leading German company,
164:, which controls the diameter of the beam of light. The controls can be used to optimize brightness, evenness of illumination, and contrast. Abbe condensers are difficult to use for magnifications of above 400X, as the aplanatic cone is only representative of a 98:
Light microscopy with and without condenser. At low magnification, using a condenser may limit the field of view, and in such cases it is preferable to not use it. At high magnification, a condenser makes borders less marked, and is generally preferable in such
258:, in combination with the NA of the objective. Different condensers vary in their maximum and minimum numerical aperture, and the numerical aperture of a single condenser varies depending on the diameter setting of the condenser 269:
The maximum NA is limited by the refractive index of the medium between the lens and the sample. As with objective lenses, a condenser lens with a maximum numerical aperture of greater than 0.95 is designed to be used under
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in Jena, offered nothing more than a very poor chromatic condenser into the late 1870s. French makers, such as Nachet, provided excellent achromatic condensers on their stands. When the leading German bacteriologist,
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used to align the optical axis of the condenser with that of the microscope. The Abbe condenser is still the basis for most modern light microscope condenser designs, even though its optical performance is poor.
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illuminator and the condenser lens. Many older microscopes house these elements in a turret-type condenser, these elements are housed in a turret below the condenser lens and rotated into place.
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that he was forced to buy a Seibert achromatic condenser for his Zeiss microscope in order to make satisfactory photographs of bacteria, Abbe produced a very good achromatic design in 1878.
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Condensers are located above the light source and under the sample in an upright microscope, and above the stage and below the light source in an
431: 54:, slide projectors, and telescopes. The concept is applicable to all kinds of radiation undergoing optical transformation, such as electrons in 242:
illumination under direct computer control. The device was first described by Dr. Jim Arlow in Microbe Hunter magazine, issue 48.
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An example of a situation where microscopy without condenser is preferable at high magnification is the evaluation of crystals (
456: 133:. It contains two lenses that produce an image of the light source that is surrounded by a blue and red color at its edges. 404: 336:
Royal Microscopical Society,"Journal of the Royal Microscopical Society", Williams and Norgate, London (1882), p.411-2
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light beam from a point light source into a parallel or converging beam to illuminate an object to be imaged.
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The sub-stage condenser focuses light through the specimen to match the aperture of the objective lens system.
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in the concentrated light path, while an achromatic compound condenser corrects for both spherical and
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The chromatic condenser, such as the Abbe where no attempt is made to correct for spherical or
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The compound achromatic condenser is corrected for both spherical and chromatic aberrations.
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used a combination of a salt water filled globe and a plano-convex lens, and shows in the '
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Chamot, E.M., "Elementary chemical microscopy", John Wiley and Sons, London (1916), p.36
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systems, which aim to improve contrast and visibility of transparent specimens.
148: 47: 317: 308: 200: 157: 181: 259: 51: 66: 354:"The Evolution of the Microscope". Bradbury. S, Pergamon Press, (1967) 19: 379:(abridged online edition), Pittsfield MA: Laurin Publishing, 2006. 147: 65: 18: 70:
A condenser between the stage and mirror of a vintage microscope
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Condensers are an essential part of any imaging device, such as
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The aplanatic condenser is corrected for spherical aberration.
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acts not only as a magnifier for the light emitted by the
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calcium pyrophosphate dihydrate crystal deposition disease
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There are three main types of microscope condenser:
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Condensers typically consist of a variable-aperture
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The first simple condensers were introduced on pre-
424:by Mortimer Abramowitz and Michael W. Davidson, 407:by Mortimer Abramowitz and Michael W. Davidson, 250:Like objective lenses, condensers vary in their 211:Specialised condensers are also used as part of 422:"Anatomy of the Microscope: Substage Condenser" 405:"Anatomy of the Microscope: Substage Condenser" 156:The Abbe condenser is named for its inventor 8: 234:object, but also as a condenser for the 329: 88: 23:A condenser (right) and its respective 7: 438:(online publication), February 2002. 176:Aplanatic and achromatic condensers 409:Olympus Microscopy Resource Center 213:Differential Interference Contrast 14: 290:microscopes in the 17th century. 246:Condensers and numerical aperture 104: 91: 254:(NA). It is NA that determines 395:"Glossary of microscope terms" 1: 217:Hoffman Modulation Contrast 473: 224:epifluorescence microscopy 274:(or, more rarely, under 388:Encyclopædia Britannica 184:condenser corrects for 166:numerical aperture (NA) 196:Specialized condensers 153: 71: 28: 457:Microscope components 426:Molecular Expressions 300:Joseph Jackson Lister 151: 69: 22: 377:Photonics Dictionary 190:chromatic aberration 186:spherical aberration 131:chromatic aberration 62:Microscope condenser 16:Type of optical lens 264:Köhler illumination 76:inverted microscope 56:electron microscopy 256:optical resolution 252:numerical aperture 154: 72: 29: 436:Micscape Magazine 464: 401:(website), 2003. 373:"Abbe condenser" 355: 352: 346: 343: 337: 334: 316:, complained to 108: 95: 472: 471: 467: 466: 465: 463: 462: 461: 442: 441: 434:by Paul James, 432:"The Condenser" 418: 364: 359: 358: 353: 349: 344: 340: 335: 331: 326: 284: 276:water immersion 248: 198: 178: 146: 123: 116: 109: 100: 96: 64: 39:that renders a 17: 12: 11: 5: 470: 468: 460: 459: 454: 444: 443: 440: 439: 429: 417: 416:External links 414: 413: 412: 402: 392: 380: 369: 368: 363: 360: 357: 356: 347: 338: 328: 327: 325: 322: 283: 280: 247: 244: 236:incident light 228:objective lens 205:phase contrast 197: 194: 177: 174: 162:iris diaphragm 145: 144:Abbe condenser 142: 141: 140: 137: 134: 122: 119: 118: 117: 110: 103: 101: 97: 90: 63: 60: 35:is an optical 15: 13: 10: 9: 6: 4: 3: 2: 469: 458: 455: 453: 450: 449: 447: 437: 433: 430: 427: 423: 420: 419: 415: 410: 406: 403: 400: 396: 393: 390: 389: 384: 383:"Abbe, Ernst" 381: 378: 374: 371: 370: 366: 365: 361: 351: 348: 342: 339: 333: 330: 323: 321: 319: 315: 310: 305: 301: 297: 293: 289: 281: 279: 277: 273: 272:oil immersion 267: 265: 261: 257: 253: 245: 243: 239: 237: 233: 229: 225: 220: 218: 214: 209: 206: 202: 195: 193: 191: 187: 183: 175: 173: 169: 167: 163: 159: 150: 143: 138: 135: 132: 128: 127: 126: 120: 114: 107: 102: 94: 89: 87: 84: 79: 77: 68: 61: 59: 57: 53: 49: 44: 42: 38: 34: 26: 21: 435: 425: 408: 398: 386: 376: 362:Bibliography 350: 341: 332: 296:Micrographia 292:Robert Hooke 285: 268: 249: 240: 221: 210: 199: 179: 170: 155: 124: 80: 73: 45: 32: 30: 314:Robert Koch 232:fluorescing 48:microscopes 446:Categories 324:References 318:Ernst Abbe 309:Carl Zeiss 288:achromatic 201:Dark field 158:Ernst Abbe 115:pictured). 182:aplanatic 83:diaphragm 52:enlargers 41:divergent 33:condenser 25:diaphragm 399:Microbus 260:aperture 168:of 0.6. 411:, 2006. 367:General 282:History 452:Lenses 304:Nobert 226:, the 99:cases. 27:(left) 121:Types 215:and 203:and 37:lens 222:In 180:An 448:: 397:, 385:, 375:, 266:. 238:. 192:. 50:, 31:A 391:.

Index


diaphragm
lens
divergent
microscopes
enlargers
electron microscopy

inverted microscope
diaphragm
Light microscopy with and without condenser. At low magnification, using a condenser may limit the field of view, and in such cases it is preferable to not use it. At high magnification, a condenser makes borders less marked, and is generally preferable in such cases.
An example of a situation where microscopy without condenser is preferable at high magnification is the evaluation of crystals (calcium pyrophosphate dihydrate crystal deposition disease pictured).
calcium pyrophosphate dihydrate crystal deposition disease
chromatic aberration

Ernst Abbe
iris diaphragm
numerical aperture (NA)
aplanatic
spherical aberration
chromatic aberration
Dark field
phase contrast
Differential Interference Contrast
Hoffman Modulation Contrast
epifluorescence microscopy
objective lens
fluorescing
incident light
numerical aperture

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