Notices
Results 1 to 5 of 5

Thread: Why do light microscopes have such a low resolution?

  1. #1 Why do light microscopes have such a low resolution? 
    Forum Freshman
    Join Date
    Nov 2008
    Posts
    62
    I am having a lot of difficulty understanding why a light microscope has such low magnification and resolution power. I know that this is somehow due to the light energy it uses being unable to detect matter smaller than half the size of its own wavelength (which is reasonably long). However, I'm not entirely clear about the detailed reasons for the reduced resolution. Clearly the magnification is low because microscopic matter below a certain size cannot be detected (because it doesn't interrupt the light waves) but I believe that the resolution problem also has something significantly to do with the type of lenses that are used in that design of microscope and the way they cause the light to refract as it passes through them. Is it that there is a specific type of lens required for a microscope of such low magnification, however this type of lens causes unavoidable effects that are detrimental to the intrument's resolution? What are the exact reasons? The resolution is to do with interference between different structures that are close together. How does this occur and why is it such a problem for a microscope that uses light? I am really confused about this!

    I hope that this post is suitable for this subforum.

    Thank you


    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Cosmic Wizard spuriousmonkey's Avatar
    Join Date
    May 2005
    Posts
    2,191
    http://en.wikipedia.org/wiki/Microscopy#Limitations


    "Kill them all and let God sort them out."

    - Arnaud Amalric

    http://spuriousforums.com/index.php
    Reply With Quote  
     

  4. #3  
    Forum Freshman
    Join Date
    Nov 2008
    Posts
    62
    Thank you very much for the link spuriousmonkey.
    So it is indeed the long wavelength of light that is responsible for the larger diffraction patterns of the structures being viewed through the microscope (thus the low resolution). The wikipedia page on optical microscopes (http://en.wikipedia.org/wiki/Optical...pe#Limitations) also states that the refractive index of the objective lens material and the numerical aperture of the lens are further causes of low resolution. In regard to the refractive index of the lens, does this mean that a lens made of a material with a refractive index as that of a standard light microscope objective causes light to refract in a way that results in blurring which affects resolution (and is this blurring due to the individual wavelengths/colors of light bending at slightly different angles?)? Is this problem something that just unavoidably occurs when light is made to pass through glass and is something that cannot be improved upon because glass is the only lens material that can be used in the design of a light microscope? Is the only way that resolution could then be slightly improved with the existing lens of glass material is to use light of a shorter wavelength such as ultraviolet? How does the numerical aperture affect the microscope resolution? Is there anything that can be done at all to alter the numerical aperture of the lens and refractive index of the objective lens to improve resolution?

    Sorry if I am making a lot of mistakes here, one of the worst things for me has always been optics. I can never seem to get my head around it! :?
    Reply With Quote  
     

  5. #4  
    Forum Cosmic Wizard spuriousmonkey's Avatar
    Join Date
    May 2005
    Posts
    2,191
    Biologists are currently more worried about other matters regarding microscopy.

    One of the most important microscopic tools is currently the use of fluorescent labels/dyes/proteins.

    For that kind of microscopy other problems are more important.
    "Kill them all and let God sort them out."

    - Arnaud Amalric

    http://spuriousforums.com/index.php
    Reply With Quote  
     

  6. #5  
    Anti-Crank AlexG's Avatar
    Join Date
    Mar 2012
    Posts
    2,809
    You have resurrected a necrotic thread, and you're shilling for something.
    Its the way nature is!
    If you dont like it, go somewhere else....
    To another universe, where the rules are simpler
    Philosophically more pleasing, more psychologically easy
    Prof Richard Feynman (1979) .....

    Das ist nicht nur nicht richtig, es ist nicht einmal falsch!"
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •