Friday, July 08, 2016

Large Area Image Sensors Tutorial

Albert Theuwissen publishes an excellent series of posts "Butting Versus Stitching" comparing different ways to combine large format image sensor out of smaller parts, some of them quite exotic - part 1, part 2.

9 comments:

  1. Albert, how many pixels are lost normally when 2 sensors are butted together please ?

    Thanks !!

    -yang ni

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  2. Albert TheuwissenJuly 8, 2016 at 9:28 PM

    It all depends on the pixel pitch of the sensors. But in many cases the loss in pixels can be limited to 1 single pixel.

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  3. I've seen a very large linear array, which was butted. The pixels next to the cut edge were of different size - probably to compensate for loss of sensitivity. Pixels pitch was significantly larger, than in current imagers, so the loss would be of "sub-pixel size"

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    1. Albert TheuwissenJuly 9, 2016 at 9:28 AM

      Sometimes a SMALLER pixel is put at the butting edge. In this way, at least you get a bit of sensitivity in the edge pixels. With a gain correction for the edge pixels, the loss can be minimized to "sub-pixel", but in that case we are talking about pixels of at least 25 um or larger.

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  4. Albert, what are the special dicing techniques employed to keep the pixel loss to a single pixel? How is chipping damage avoided? How does one obviate the need for a guard ring?

    or are you talking about 100+um pixel dimensions?

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    1. Albert TheuwissenJuly 9, 2016 at 9:31 AM

      Sometimes special/extra precautions are taken during the dicing. Or, even a combination of a wider trench etch + dicing is used to prefectly define the edge of the die and to avoid chipping. I am not talking of 100+ um pixels, but even with pixels of 25 um, a loss of maximum 1 pixel is possible.

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    2. Albert do you talk about plasma singulation method pleas? Is this popular in dicing industry pleas? thank!!

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  5. Since Olympus published a paper on its 2MP sensor that has GS w FPS=10000, I have wondered how Olympus could "stich" the 10 of these to get 20MP sensor w similar FPS and GS.
    Glad to see others are tackling a more general problem.

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  6. Albert TheuwissenJuly 14, 2016 at 10:09 PM

    Thanks for your comments and your support. More to come about various stitching technologies after the holidays.

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