Skip to main content

2012 | OriginalPaper | Buchkapitel

Telecentric, Fresnel and Micro Lenses

verfasst von : Spencer D. Luster, Dr. Bruce G. Batchelor

Erschienen in: Machine Vision Handbook

Verlag: Springer London

Aktivieren Sie unsere intelligente Suche um passende Fachinhalte oder Patente zu finden.

search-config
loading …

Abstract

Telecentric lenses provide constant perspective and large magnification depth of field. For this reason, they are often well suited for gauging and a variety of other demanding Machine Vision applications. This is especially true when viewing objects that have variable depth and/or lateral position. Lighting issues relating to the use of telecentric optics for viewing and lighting are discussed, together with their ability to provide sensitive detection of defects in clear or flat and shiny materials. Telecentric lenses can view objects, with constant perspective, anywhere within a cylindrical volume. On the other hand, hypercentric lenses can view objects within a conical region, whose apex is in front of the lens. (A fish-eye lens views objects within a conical region, whose apex is behind the lens.) As a result, hypercentric lenses are able to view the top and sides of an a cylinder simultaneously.
By adding a spacer between certain types of hypercentric lens and the camera, it is possible to view inside a bore, even when the viewing aperture, at the camera end of the bore, is very small. Both telecentric and hypercentric lenses are only able to work effectively if the front refracting element is larger than the object being viewed. Manufacturing large conventional (i.e. curved-surface) lenses is very expensive. Fresnel lenses provide a convenient alternative. There are three common types of optical component made by forming numerous very small grooves and/or mounds on a plane surface. Fresnel lenses employ very fine prismatic surface features on a thin plane plate. Micro-lens arrays consist of numerous small lenses (lenslets) placed close together on a plane substrate. In both of these cases, the optical formulae explained in Chap.​ 5 are applicable, because the surface features, while small, are still much larger than the wavelength of light. On the other hand, Diffraction (or Binary) optical components have such small surface features that they cause interference due to diffraction; refraction usually plays no significant part in the operation of these devices. Some hybrid refractive-diffractive lenses are made but these are uncommon.

Sie haben noch keine Lizenz? Dann Informieren Sie sich jetzt über unsere Produkte:

Springer Professional "Wirtschaft+Technik"

Online-Abonnement

Mit Springer Professional "Wirtschaft+Technik" erhalten Sie Zugriff auf:

  • über 102.000 Bücher
  • über 537 Zeitschriften

aus folgenden Fachgebieten:

  • Automobil + Motoren
  • Bauwesen + Immobilien
  • Business IT + Informatik
  • Elektrotechnik + Elektronik
  • Energie + Nachhaltigkeit
  • Finance + Banking
  • Management + Führung
  • Marketing + Vertrieb
  • Maschinenbau + Werkstoffe
  • Versicherung + Risiko

Jetzt Wissensvorsprung sichern!

Springer Professional "Technik"

Online-Abonnement

Mit Springer Professional "Technik" erhalten Sie Zugriff auf:

  • über 67.000 Bücher
  • über 390 Zeitschriften

aus folgenden Fachgebieten:

  • Automobil + Motoren
  • Bauwesen + Immobilien
  • Business IT + Informatik
  • Elektrotechnik + Elektronik
  • Energie + Nachhaltigkeit
  • Maschinenbau + Werkstoffe




 

Jetzt Wissensvorsprung sichern!

Springer Professional "Wirtschaft"

Online-Abonnement

Mit Springer Professional "Wirtschaft" erhalten Sie Zugriff auf:

  • über 67.000 Bücher
  • über 340 Zeitschriften

aus folgenden Fachgebieten:

  • Bauwesen + Immobilien
  • Business IT + Informatik
  • Finance + Banking
  • Management + Führung
  • Marketing + Vertrieb
  • Versicherung + Risiko




Jetzt Wissensvorsprung sichern!

Literatur
Zurück zum Zitat AZoOptics, Mona Vale, Accessed 12th July 2009 AZoOptics, Mona Vale, Accessed 12th July 2009
Metadaten
Titel
Telecentric, Fresnel and Micro Lenses
verfasst von
Spencer D. Luster
Dr. Bruce G. Batchelor
Copyright-Jahr
2012
Verlag
Springer London
DOI
https://doi.org/10.1007/978-1-84996-169-1_6

Neuer Inhalt