Have you seen anything (published before Sep 2, 1980) as described in this US Patent Application "Optical position location apparatus" US 4420261 A, that utilizes or describes either a optical scanner/stationary detector in conjunction with a scanner/stationary optical light?

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    I've mentioned this before, but I'm a little worried about this question and answer. Please realize that a patent from 1980 is well past the grounds for a typical prior art request. That's alright, and if you want to bring that content to the site because it interests you, that's great. But given that you've now self-answered twice with posts that sounded like advertisements, I was hoping to reach out and double-check that we're on the same page about what this site is for. Aug 29, 2015 at 18:28
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    If you'd like to know whether US4851616 might have qualified as prior art for this patent, we can help with that, but you'll have to include it in the question itself and make sure that's the question you're asking. What we can't help with, unfortunately, is if you're just hoping to essentially announce the infringement. I understand your frustration and I wish there was something we could do, but that's just not what our site is here for. Aug 29, 2015 at 18:28
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    Your best bet if you're hoping to take action against this in any way would be to speak with a patent attorney to learn about laws that may or may not come into play under these specific conditions, so that you can understand your rights at this stage, with both patents being long-expired. If you have any questions about what I've said here, please don't hesitate to ask. I'd even be open to starting a private chat session with you to go over how we can make sure you're getting the best use out of our site. Aug 29, 2015 at 18:29

1 Answer 1



Priority date: Jan 3, 1966

This is the first and earliest reference to the use of a scanning beam and synchronous detection using a passive reflector as a position/location detector.

NOTE: This NOT time-of-flight or Amplitude detection. This is instead taking into account that this scanning beam method knows it's XYZ position and when the target reflector is lit up, the position is known.

For CRT's, the beam brightness was extremely bright because the entire tube face was lit by just one scanning beam as example 1/1000 beam the size of the screen size. (If 1000x1000 points = 1 lux overall brightness, means an ordinary CRT beam was one million lux) (NTSC = 525 horizontal lines, each scanned in 62.5 microseconds) So the "target-reflector" could be a dirty finger tip.

This reflected bright beam allowed the position of the object to be picked up by looking for a pulsed signal to be returned to a single photocell. The reflection of the light is detected and latches the XYZ position of the beam current position. This made the entire hardware cost to be less than $1.

BACKGROUND: This invention came out of the consideration for automatically-guided-vehicular (AGV) loading of rolls of paper into printing presses (AGV). At this time (1966), the only significant consideration for AGV was to printing presses using 15 miles of paper every hour per roll and typically 12, 1 ton rolls per newspaper press every hour. This is the background of the inventor WALES. CROWLEY worked for ADAGE (the first Computer-Added-Design CAD solution) and was responsible for user interface such as light pens, EEG/EKG electrodes, optic nerve vision tracker and such, his first touch screen used PPG resist coated glass from a frost free cold drink retail case. The two inventors ended up working at Butler Automatic, who became the leader in automatic press splicing. Crowley and Wales design many industry first in the 80's. After Wales passed in 1991 ... Crowley continued and to this day, introducing many firsts in the industry as breakthrough products.

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    Do you think you could whittle this down to highlight the important and relevant parts of your patent? As it stands, unfortunately, it reads kind of like an advertisement for this patent. This might just be a matter of removing the "background" section that you've included, but I was hoping you could review it on your own so as not to lose anything that you do consider relevant. Aug 29, 2015 at 18:10
  • There is a great deal that the two of you don't know about: patent prosecution Sep 5, 2015 at 15:48
  • It is my purpose to explain by example some important principals of patent prosecution and enforcement as they apply to prior-art and to an important current technology's development. Sep 5, 2015 at 16:20
  • US 4,851,616 A has a priority date of January 3, 1986 and therefore would not qualify as prior art for US 4,420,261, which has a priority date of September 2, 1980. Thank you for pointing out the error, it has been corrected in Espacenet and a correction is also pending at the USPTO.
    – Parker
    Sep 27, 2015 at 12:13
  • The intentional misrepresentation of the priority date means this answer either needs to be corrected or removed.
    – Eric S
    Mar 22, 2017 at 14:13

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