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  1. #1
    Mustafa Umut Sarac's Avatar
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    Zeiss way of semiconductor making lens

    Hello ,

    I watched a Deutche Welle program and it was about deep ultraviolet focusing.

    An zeiss expert told that traditional lenses are not precise for semiconductor making and they switched to mirror lenses.

    He said if someone enlarge a zeiss mirror to germany size , highest peak will be 5 milimeters.

    And I saw the mirror grinding machine , mirrors are smaller than 10 cms , it was like telescop grinding machine , a mirror glass lies and a toothbrush size
    grinder move and turn on the mirror.

    I want to ask , how a small size grinder carve out a precise mirror from big glass ?

    What describes its movement on the glass ?

    Is there a big format mirror camera lens at the market ?

    How can it be done ?

    I am thinking flexing a stainless steel plate and take from front of it .

    Best ,

    Mustafa Umut Sarac

  2. #2
    Sparky's Avatar
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    Mustafa - I think you are in the wrong forum... I have seen you post many things here which are beyond the scope of pretty much everyone - it's great that you have unusual interests - I support that. if you have any questions about things like 'developing film' - or something regarding how to get 'sharper photos' or something like that - I'm sure people will be more than happy to help...!

  3. #3
    Mustafa Umut Sarac's Avatar
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    Hmmm , Sparky , I read my post again and I agree , I am at the wrong forum. May be I am trusting apug members too much , I developed myself quite fast and now my questions are too far.
    But there are people who has more ideas than me also , for example oil rig man from Norway , I forgot his name.
    But I have to post and awaken the minds also. I think its funny someone - a high school student - read my posts and dive in to the google with many unknown questions , after half hour surfing , he will say wow !
    Wow factor is important here , thats why everyone here, I guess...

  4. #4
    Ole
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    I don't have more ideas, it's just that I'm extremely good at collating information.

    Some of the reasons for using mirrors instead of lenses are:

    1) Wavelength: To get the necessary precision/resolution, UV light is necessary. There are few suitable substances for making ultra-high-precision UV-transparent lenses.

    2) Precision: A mirror has one surface, a lens has two. That makes it four times more difficult to make a sufficiently precise lens!

    As to how the grinding is done, I have no idea.

    There are no LF mirror lenses on the market, but it is very easy to hook a LF camera up to a mirror telescope.
    -- Ole Tjugen, Luddite Elitist
    Norway

  5. #5
    Mustafa Umut Sarac's Avatar
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    This is very interesting , they are coating the mirror 1 to 40 layers and each layer increase the reflectance.
    May be Sarkozy glasses - you know -mirror- coated transparent lenses
    are now seems more interesting.

    Manufacturing the reflective optics presents another challenge. The mirrors have a special aspheric shape and are made by a computer-controlled figuring and polishing process. To complicate matters, the coating thickness must be adjusted across the mirror surface to correct for the change in the angle of incidence of the light

  6. #6
    Sirius Glass's Avatar
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    Reflective optics are used for IR work because refraction optics take too much of a toll on the transmitted light. Furthermore, refractive optics are not uniform across the light spectrum whereas reflective optics are. Hence the use of a large mirror for systems such as Hubble telescope. [Yes, I know that it helps to put the tool in right side up so that the lens is ground to the proper focal length.]

    Steve
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  7. #7

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    The book you would want to read about optical fabrication - http://lindsaybks.com/bks/expphy/index.html
    It includes details of optical grinding machines. A common type is the draper machine. Achromatic lenses
    with quartz and rocksalt elements have been used for ultraviolet purposes, but mirrors are probably better
    provided they are used over a narrow enough field of view to avoid significant coma.

    Precision: A mirror has one surface, a lens has two. That makes it four times more difficult to
    make a sufficiently precise lens!
    Actually, most lenses have 4 surfaces (assuming they are achromatic). On the flip side, a refractive surface
    does not have to be as precise as a reflective one and multi-element lenses can be well corrected with all
    spherical surfaces.

  8. #8

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    First the small UV mirrors are made the same way as Telescope mirror. You load the tool with finer and finer grinding media. Then you use a optically flat glass and the interference patterns generated to hand figure the lens to the correct shape. Most reflective coatings the material is selected for reflectivity in the wave length that will be used. This why gold is used in the IR range, and in the visible range silver and aluminum are used. A protective coating is deposited on the silver and aluminum mirrors to keep them from oxidizing. You can purchase the mirror for a very costly 1/4 wave to a cheaper 1/2 wave tolerances form a parabolic.
    It's not the camera......

  9. #9
    Mustafa Umut Sarac's Avatar
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    3D Fan , if you have the book , please share the chapter with us , money is tight here



 

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