137:
126:
29:
465:
249:
alone. Elements may be cemented by oil or a soft cement in the case when the differential thermal expansion of crown and flint glasses causes hard or cured cements to warp or fracture. With larger elements, it is ideal to separate the lenses using a spacer. In a hard-cemented doublet, the lenses are
262:
was traditionally used for this purpose. Some doublets use no adhesive between the lenses, relying on external fixturing to hold them together, either because the optical design requires a gap or because
306:
Cementing elements can simplify raytracing operations as the cement may nearly always be ignored, with the tracer treating the ray as if it refracts directly from one element into the next.
186:
paired together. Such an arrangement allows more optical surfaces, thicknesses, and formulations, especially as the space between lenses may be considered an "element". With additional
267:
differences between the two lenses will not allow cementing. These are called "un-cemented", "air-spaced" or "broken contact" doublets. A sub-type of air-spaced doublet is the
322:
Cementing elements requires a high precision to ensure correct centering of the cemented components. This difficulty greatly increases on groups of more than two elements.
271:, a design where elements are widely spaced to save on the amount of glass used or where the elements cannot be cemented because they have strongly dissimilar curvatures.
136:
440:
A guide to instrument design – Scientific
Instrument Manufacturers' Association of Great Britain, British Scientific Instrument Research Association, page 184
312:
Provides superior control for minimising spherochromatism and other aberrations, allowing the creation of more advanced optical systems using fewer elements.
187:
429:
506:
93:
65:
112:
72:
46:
50:
79:
215:
191:
163:
325:
Precision cementing is high in manufacturing cost. It is often cheaper to AR-coat two air-spaced elements.
61:
360:
Clarkson, E. N. K.; Levi-Setti, R. L. (1975), "Trilobite eyes and the optics of
Descartes and Huygens",
245:
Doublets can be air-spaced, cemented, or "oiled". Oiled doublets hold the optical fluid in place with
499:
17:
39:
535:
293:
lens that is difficult to mount with an equivalent doublet made from two higher-power lenses.
492:
371:
227:
211:
207:
159:
155:
86:
8:
530:
223:
480:
375:
416:
130:
154:; the rear doublet is glued and convergent. This arrangement was better at correcting
387:
264:
151:
412:
379:
362:
219:
525:
335:
309:
Cemented groups may assist to decrease the physical length of the optical system.
246:
150:
with four elements, comprising two doublets. The front doublet is air-gapped and
286:
To prevent total reflection at the air-film interface due to critical ray angle.
476:
297:
There are several advantages and disadvantages to cementing elements together:
519:
290:
259:
179:
141:
340:
268:
391:
231:
183:
147:
283:
To eliminate the reflection losses of two air-glass surface interfaces.
239:
125:
383:
235:
202:
Doublets can come in many forms, though most commercial doublets are
238:, which are now extinct, had natural doublet lenses in their eyes.
234:. This combination produces a better image than a simple lens. Some
28:
251:
203:
472:
464:
449:
Fred A. Carson, Basic optics and optical instruments, page AJ-4
430:
Fred A. Carson, Basic optics and optical instruments, page 4-32
171:
144:
255:
279:
Lenses may be cemented together for any of several reasons:
254:
with mechanical strength, such as optically transparent
190:, optical designers have more latitude to correct more
218:. The lenses are made from glasses with different
53:. Unsourced material may be challenged and removed.
359:
517:
226:. Often one element is a positive lens made of
500:
407:Kingslake, R. (2010). Johnson, R. B. (ed.).
507:
493:
406:
353:
230:and the other is a negative lens made of
113:Learn how and when to remove this message
135:
124:
411:(2nd ed.). SPIE Press. p. 5.
518:
459:
402:
400:
51:adding citations to reliable sources
22:
13:
417:10.1016/B978-0-12-374301-5.00005-X
14:
547:
397:
463:
316:
206:, which are optimized to reduce
27:
38:needs additional citations for
443:
434:
423:
242:can also be made as doublets.
1:
346:
300:
479:. You can help Knowledge by
7:
329:
166:than previous lens designs.
10:
552:
458:
15:
274:
222:and different amounts of
409:Lens Design Fundamentals
197:
18:Doublet (disambiguation)
475:-related article is a
167:
133:
160:chromatic aberrations
139:
128:
250:held together by an
212:spherical aberration
210:while also reducing
208:chromatic aberration
47:improve this article
16:For other uses, see
376:1975Natur.254..663C
216:optical aberrations
192:optical aberrations
62:"Doublet" lens
220:refractive indices
194:more thoroughly.
188:degrees of freedom
168:
134:
131:achromatic doublet
488:
487:
289:To replace a low-
265:thermal expansion
123:
122:
115:
97:
543:
509:
502:
495:
467:
460:
450:
447:
441:
438:
432:
427:
421:
420:
404:
395:
394:
384:10.1038/254663a0
357:
118:
111:
107:
104:
98:
96:
55:
31:
23:
551:
550:
546:
545:
544:
542:
541:
540:
516:
515:
514:
513:
456:
454:
453:
448:
444:
439:
435:
428:
424:
405:
398:
370:(5502): 663–7,
358:
354:
349:
336:Achromatic lens
332:
319:
303:
277:
247:surface tension
200:
182:made up of two
119:
108:
102:
99:
56:
54:
44:
32:
21:
12:
11:
5:
549:
539:
538:
533:
528:
512:
511:
504:
497:
489:
486:
485:
468:
452:
451:
442:
433:
422:
396:
351:
350:
348:
345:
344:
343:
338:
331:
328:
327:
326:
323:
318:
315:
314:
313:
310:
307:
302:
299:
295:
294:
287:
284:
276:
273:
199:
196:
121:
120:
35:
33:
26:
9:
6:
4:
3:
2:
548:
537:
534:
532:
529:
527:
524:
523:
521:
510:
505:
503:
498:
496:
491:
490:
484:
482:
478:
474:
469:
466:
462:
461:
457:
446:
437:
431:
426:
418:
414:
410:
403:
401:
393:
389:
385:
381:
377:
373:
369:
365:
364:
356:
352:
342:
339:
337:
334:
333:
324:
321:
320:
317:Disadvantages
311:
308:
305:
304:
298:
292:
288:
285:
282:
281:
280:
272:
270:
266:
261:
260:Canada balsam
257:
253:
248:
243:
241:
237:
233:
229:
225:
221:
217:
213:
209:
205:
195:
193:
189:
185:
184:simple lenses
181:
178:is a type of
177:
173:
165:
161:
157:
153:
149:
146:
143:
138:
132:
127:
117:
114:
106:
103:December 2009
95:
92:
88:
85:
81:
78:
74:
71:
67:
64: –
63:
59:
58:Find sources:
52:
48:
42:
41:
36:This article
34:
30:
25:
24:
19:
536:Optics stubs
481:expanding it
470:
455:
445:
436:
425:
408:
367:
361:
355:
341:Triplet lens
296:
278:
244:
201:
175:
169:
109:
100:
90:
83:
76:
69:
57:
45:Please help
40:verification
37:
240:Apochromats
232:flint glass
228:crown glass
164:astigmatism
148:camera lens
531:2 (number)
520:Categories
347:References
301:Advantages
236:Trilobites
224:dispersion
214:and other
142:Carl Zeiss
73:newspapers
204:achromats
156:spherical
152:divergent
330:See also
252:adhesive
392:1091864
372:Bibcode
269:dialyte
176:doublet
140:An old
87:scholar
526:Lenses
473:optics
390:
363:Nature
275:Cement
172:optics
145:Tessar
89:
82:
75:
68:
60:
471:This
291:power
256:epoxy
198:Types
94:JSTOR
80:books
477:stub
388:PMID
180:lens
174:, a
162:and
158:and
66:news
413:doi
380:doi
368:254
170:In
129:An
49:by
522::
399:^
386:,
378:,
366:,
258:.
508:e
501:t
494:v
483:.
419:.
415::
382::
374::
116:)
110:(
105:)
101:(
91:·
84:·
77:·
70:·
43:.
20:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
