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First Surface Mirror?

Discussion in 'TVs' started by Les, Jan 8, 2005.

  1. Les

    Les
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    Hi

    What is this 'First Surface Mirror'? I see it in a most (if not all) DLP TV specifications I come across.
     
  2. Chris5

    Chris5
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    I assume it means that the only/ first surface the light from the lamp hits (before it reaches the eye) is the mirror on the DLP chip
     
  3. Les

    Les
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    Hmmm - seems a bit redundant to stress it on all the specs if thats all it means. Thanks anyway.
     
  4. Nick_UK

    Nick_UK
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    First surface mirrors are special mirrors. In a conventional mirror, the reflective surface is on the back side of the glass, which would be no good for DLP projection, because the glass itself would also act as a reflector, causing a double image. In DLP sets, the reflective surface is deposited on the front face of the glass, and it's called a First Surface Mirror
     
  5. LV426

    LV426
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    ...and I'd guess they aren't talking about the miniscule mirrors on the DMD, but about the huge one inside the back of the set......
     
  6. Les

    Les
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    Ah OK, that makes sense. But still, seems an odd thing to mention in all the different manufacturers specs - unless .... maybe the older type RP mirrors were indeed 'second surface mirrors' :)
     
  7. Nick_UK

    Nick_UK
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    It's also the reason why the ageing of the mirror has to be a consideration in the choice of a DLP TV, because First Surface Mirrors deteriorate faster than ordinary mirrors, because they have no glass protecting them.
     
  8. Phil Harris

    Phil Harris
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    Why would the aluminised surface on a first surface mirror deteriorate faster than a regular mirror? The surface is coated to prevent oxidisation.
    The reason for glass being on the front of regular mirrors is to protect them from scratching, what exactly is going to scratch the mirror on a DLP?
    First surface mirrors are used in all reflector telescopes and many photographic applications. The life span of these devices is not governed by deterioration of FSM's.
    Yet more misinformation I'm afraid...
     
  9. Nick_UK

    Nick_UK
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    The surface coating is very thin, and can be penetrated in time.

    Not so ! Although the glass does protect from scratching, it is also there to keep corrosive agents out.

    That all depends on the quality of the mirror, and the quality of the coating. Some mirrors in reflector telescopes cost more than a 50" DLP TV !

    That is your opinion :)
     

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