Haloing and CRT cooling

Discussion in 'Projectors, Screens & Video Processors' started by joerg, Sep 12, 2005.

  1. joerg

    joerg
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    Hi it would be great to get some critics :mad: and responses to this maybe strange idea I have. :D

    I was wondering if it is possible to cool the crt face instead of using the glycol with a sort of air cooling.

    The most of the halo is the result of the light reflection between the crt-face (glass with phosphor coating) and the glass to seal the glycol chamber. In my experience the halo that is produced inside the lens isn't so strong.
    I would like to try to remove the Glass plate that seals the glycol chamber and install some kind of air-condition for the crt face.
    My idea is to create a curtain out of cold air. On top of the face the cold air should be blown over the face and on the bottom there should be a suction pipe.
    The problems I see so fare are:

    - To ensure that all parts of the CRT face will get the same heat transfer
    - Risk of water condensation
    - Flare due to density differences in the Air

    OK what do you think only nonsense or worth a try? :smashin:

    Shears
    Joerg
     
  2. Peter Parker

    Peter Parker
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    I'm just guessing, but I think the liquid also acts as a coupling medium to reduce reflections/refraction between the different glass faces rather than just act as a coolant.

    Air gaps allow for light refraction and I've seen this when playing around with lens filters - by reducing the gap I reduced considerably the halo/flare effect. Using a liquid between them would have been better still.

    Gary.
     
  3. joerg

    joerg
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    Hi Gary,
    thanks for your reply,

    you are right when you move the glass plates closer together the halo will be smaller. I think the reason for that is that glass has a specific reflection angle and if you move the plates closer together the halo will get smaller but brigther.
    You are propably also right that the fluend in not just cooling the crt but also there for the liquid coopling.
    So maybe you can find a fluent that will change the refletion angle between the glass plate and the fluent so that the halo should be less disturbing.

    In LC units the Glass faces are curved so that the refletions won`t fall back on to the CRT face so they are not producing any halo.

    My point is to take away the second glass plate so that there won't be any reflections.

    There will be another aspect we should think about and this is that the this distance tube lens is calculated expecialy for each unit so that I will propably have to adjust the lens tube distance.

    Right now I am looking for a old crt to try modify this unit and see what happens.



    Shears
    Joerg
    :hiya:
     
  4. Peter Parker

    Peter Parker
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    Have you tried it to see what the image looks like without the glass plate? Can you do that without any damage to the pj?

    Gary.
     

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