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IR receiver question

Discussion in 'Electronic Design' started by Richard, Sep 11, 2003.

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  1. Richard

    Richard Guest

    I am looking at some US patents. You can look them up pretty quickly at
    www.uspto.gov, might have to install a TIFF viewer. Just follow the
    instructions.

    Anyway! I am reviewing patent #5,473,461. I'm surprised that this is a
    fairly recent patent, and that is was granted in the first place. Surely,
    someone must have done this before! Almost everyone hook up photodiodes to
    an amplifier of one sort to another (with 2 inputs and an output, duh!) You
    mean NO ONE ever used a low pass filter to filter out background noise? If
    you are interested, please review the patent and comment. No, you don't
    have to look at the whole thing. Just look at the first claim, and the
    circuit if needed.

    I think the basic claim is an optical receiver with a low pass filter in it.

    Thanks for your comments!

    p.s. I'm not looking for bashing comments of our beloved PTO. I have
    enough of those :) Just some background prior art info.
     
  2. Jim Thompson

    Jim Thompson Guest

    I would think someone would have already done it. But the PTO issues
    patents for just about anything that crosses their desks.

    But it's possible no one filed for it. But that doesn't mean the
    patent will hold water... prior art in a product will nullify the
    patent.

    ...Jim Thompson
     
  3. One could posit that this is a sign of how good the patent lawyers have
    gotten at convincing their clients not to submit patents that aren't likely
    to be approved.

    Realistically I think there's a bit of truth to that pollyanna-ish
    perspective. It costs so #[email protected]#[email protected] much, and takes so long, to file a patent
    that the only people who are going to do it are:

    (a) big companies who can afford full-time patent lawyers, who are likely to
    know how to get a patent accepted;
    (b) crackpot inventors who are going to persist in re-filing until their
    patent gets accepted;
    (c) individuals and small companies who have a seriously good and valuable
    idea, and have done their homework.

    Lord knows I'm not likely to patent anything anytime soon; no matter how
    good my idea, the filing costs would put my small company out of business
    before I had a chance to profit from the patent. I can't afford a $10k
    rubber stamp, especially if the rubber-stamping process grants me nothing
    more than the right to pay a lawyer to belatedly discover the patent wasn't
    enforceable due to something the PTO didn't research at the time. If
    patents were meaningfully peer-reviewed like journal articles, I might feel
    differently.

    Anyway, to respond to the initial post, "an optical receiver with a low pass
    filter in it" is surely something with prior art all over it. The first
    thing that comes to mind is the "magnetic levitation" systems based on an
    optical position sensor and an electromagnet - a bit of Googling will find
    schematics.
     
  4. Jim Thompson

    Jim Thompson Guest

    The only patents I have were paid for by the client companies who
    insisted on patenting something.

    But I have literally thousands of trade secrets that I have
    well-documented (and witnessed) when I first used them. If someone
    attempts to patent them I'll simply declare them public domain.

    ...Jim Thompson
     
  5. Jim Thompson

    Jim Thompson Guest

    My creations actually are "public"... you just have to trace a chip to
    find them ;-)

    ...Jim Thompson
     
  6. Europe isn't significantly different, IIRC. They may have a
    challenge period, but I don't believe trade-secrets trump
    patents.
    You're right. Trade secret status does *not* prevent someone
    from patenting your widget. You then lose the rights to *your*
    widget. The whole idea of a patent is to teach the art to
    others. If you choose to keep the art private you lose all
    rights. ...even *your* (undisclosed) prior art doesn't count.
    You are. The reason is simple (see above). A patent is a
    license granted for the free teaching of an art. No teaching, no
    license.
    I ain't no damned lawyer, but work with the IP variety on a
    regular basis.
     
  7. Keith R. Williams wrote...
    No, I think Jim's right, it's public disclosure that trumps
    all the rest. You don't actually have to say what the secret
    is, just disclose it publically in a schematic drawing of
    record in the field of interest, for example in the datasheet
    of an IC, or in a manual for an instrument openly shipped to
    customers in the field, with records proving shipment dates.

    We'd better check out photodiode amplifier patent #5,473,461
    that Richard's talking about.

    Thanks,
    - Win
     
  8. Keith R. Williams wrote...
    No, I think Jim's right, it's public disclosure that trumps
    all the rest. You don't actually have to say what the secret
    is, just disclose it publically in a schematic drawing of
    record in the field of interest, for example in the datasheet
    of an IC, or in a manual for an instrument openly shipped to
    customers in the field, with records proving shipment dates.

    We'd better check out photodiode amplifier patent #5,473,461
    that Richard's talking about. ... Yep, that's old stuff.

    Thanks,
    - Win
     
  9. Jim Thompson

    Jim Thompson Guest

    If I've been manufacturing a device for years which uses my ideas, and
    someone comes along and patents them, I can challenge on the basis of
    "first reduction to practice". Also on "uniqueness".

    ...Jim Thompson
     
  10. Jim Thompson

    Jim Thompson Guest

    Yep, public disclosure, no matter that you didn't point out the
    uniqueness of a particular part of the schematic.

    I think patent #5,473,461 isn't worth the powder to blow it to hell.
    It has the earmarks though of a company probably bent on suing
    everyone in sight and seeing which suckers pay. Your best protection
    is records that prove dates.

    ...Jim Thompson
     
  11. Bob May

    Bob May Guest

    Actually, in some way or another, depending upon the particular application,
    some low AND high pass filtering needs to be done at some point between the
    diode and the output. It is a given to the process.
     
  12. Seems to me that I've seen similar circuits, using tubes and at much
    higher pulse rates, for eliminating clutter from the target
    information in radar sets. These were known as 'fixes' and long ago
    may have been classified information.


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