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New Optical Device!

  1. Jun 7, 2014 #1
    Wow! A physics forum! Here's the device I filed a U.S. patent for, so I'm wondering what to do next?

    I've talked to the chair of my physics department and he said the amount of light arriving at each pixel is very small. CCDs are becoming very efficient, so this could become viable in the next 20 years. There's also the possibility that the source image is presented via a 2D laser array.

    This has some properties of a 2D collimator, but also some properties of a pinhole light field mask.

    I've shown this presentation to a bunch of people in industry, but they aren't helpful, so I must try a different method.
    Should I submit a paper?
    Write a conference poster?
    Any other ideas?

  2. jcsd
  3. Jun 7, 2014 #2


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    Are you familiar with single-pixel cameras?
    See http://dsp.rice.edu/research/compressive-sensing/single-pixel-camera [Broken]

    Also note that CCD is not the only technology; you should also become familiar with CMOS cameras.

    Your consultant was correct: small pinholes admit very little light, so exposure times may need to be increased.

    Instead of expanding the image inside the camera, you can use a tapered optical fiber bundle to connect the pinholes to their corresponding pixels. This reduces overall size of the camera. Read over http://spie.org/x32419.xml

    My suggestion is that you build a demonstration prototype - people want to see the real deal. Then spend some time optimizing it. If you know electronics you could be the optical sensor chips and build your own system; if not, just pop off the lens from a cheap web cam, and match your pinhole structure to the onboard pixel array.

    Your project is in the R&D phase; it is not a scientific project, so papers and posters wouldn't seem appropriate. Certainly the scientific principles are quite old: they were used during the renaissance!

    See https://en.wikipedia.org/wiki/Pinhole_camera
    Last edited by a moderator: May 6, 2017
  4. Jun 7, 2014 #3

    Vanadium 50

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    I'm not sure what your device actually does. Can you provide a link to the actual patent application?
  5. Jun 8, 2014 #4


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    Take a look at how a flexible endoscope works. They use an array of fibres instead of an array of pinholes but otherwise the principle looks very similar.

    PS Good inventions solve problems. What problem does your invention solve?
  6. Jun 8, 2014 #5


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    All those tiny tubes are limited by diffraction - if you want an image of a reasonable quality, you need either very large tubes (of the order of 1mm) for each pixel, additional optics in front of the tubes (but then you get exactly those flexible endoscopes) or your tubes have to end very close to the object you want to imagine (then the resolution is comparable to the distance to the object or the tube diameter, whatever is larger).

    The first approach is completely impractical, the optics approach exists as commercial product, for the last approach I don't see an application (and glass fibre bundles are much better than black boxes).

    CCDs are very efficient. Less than a factor 10 away from the absolute physical limit, some special CCDs achieve a quantum efficiency of 90% for some frequency range.
  7. Jun 8, 2014 #6
    Wow, thanks for all of the responses! When I can afford a Makerbot, I'll start testing prototypes.

    Diffraction is a very interesting question, does it occur at the input to a pinhole or its output.
    If it occurs at the input, then my holes are limited in size to the wavelength of the light.
    If it occurs at the output, then I must simply place the hole output close to the detector.

    Does anybody know where diffraction occurs? If not, can anybody think of a good way to test this?

    The invention is very similar to NASA's Lunar Laser Communication Demonstration, instead of sending four laser beams to get one signal, you send N laser beams and collect N signals.
    Under 200 ft, a smart phone could be used instead of lasers.
    It also might be better than collimators at X-rays, because collimators are designed to absorb some of the unaligned X-rays, while this method absorbs all of the unaligned X-rays.
  8. Jun 8, 2014 #7
    I guess I need to conduct a "thick" double slit experiment.
  9. Jun 9, 2014 #8


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    You don't say what material the body is made of or what the holes are filled with? The assumption is the holes are filled with air? Vacuum? Other materials might be better depending on the purpose of this invention.
  10. Jun 9, 2014 #9


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    The simplest theory of diffraction was by Christiaan Huyghens, ~1678:

    It occurs at every edge - so inlets and outlets. The smaller the holes, the greater the diffraction, becoming maximal as the hole (or bump) becomes similar in size to the wavelength.

    Also works for water, so you can do experiments on the cheap in your own bathtub!

    Or use a laser pointer, clamped to a bench, and then introduce various small tubes, holes, bumpy surfaces. Easiest to see in a darkened room. You will also see interference effects such as Poisson's spot: http://io9.com/5707749/poissons-spot--the-greatest-burn-in-physics

    The spot is surrounded by rings.

    I've worked with devices similar to your proposal; one consists of an array of micro-lenses:

    You can build a Shack-Harmann device with such an array:

    When working with electron imaging I have made extensive use of microchannel plates, which are arrays of very fine tubes; for my application the tubes were 10 microns across, though you can get them as small as 2 microns:

    Be sure to download the pdf on how they work. You can contact them and see if they will send you a busted (cracked) plate ... that will give you a nice array of tiny holes to experiment with.
  11. Jun 9, 2014 #10


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    CWatter's "PS" was key. If the people in industry are not interested then it is most likely because as far as they can tell your invention does not solve one of their problems. I am in industry and I can tell you that I get pitched a lot of inventions. I am helpful to the ones that are helpful to me and I am not helpful to the ones that are not helpful to me.

    As far as what to do next, that depends on your goal. If you just want to have people be aware of it then a paper or a conference poster would certainly do the trick. However, if you want it to be commercially used then you need to understand what problem it solves.

    If you cannot identify a problem it solves then it probably has no economic value at this time.

    If you can identify what problem is solves then you need to target the people/industry that have that problem. If you do that and there still is no interest, then probably they have a better solution already or your solution is not feasible for some other reason.
  12. Jun 9, 2014 #11


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    Both. It is easy to fix at the output: Attach the detectors directly to the holes.

    If you use holes the size of the wavelength, you do not see anything - the whole image becomes one pixel. Smaller holes won't even transmit your light at all.

    Use a very small pinhole to test it. No tube necessary.

    I don't see the similarity. They just used four different receivers on the ground to send and receive signals. And the beam had a diameter of 10cm and more.

    X-ray telescopes use a related approach with many metal sheets, indeed.
  13. Jun 9, 2014 #12
    So, unlike an optical fiber, I do not want internal reflection, I want internal absorption. In order to accomplish this my hole cores are a clear plastic PMMA and my walls are a black plastic of PMMA and charcoal.
    The walls being the same material as the holes should prevent reflection.
  14. Jun 9, 2014 #13


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    So, as has been asked repeatedly, what need does this fill? Filing for a patent and having something people want/need are two different things.
  15. Jun 10, 2014 #14


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    Can you explain why?
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