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 Replies: 14 / Views: 1,652 |
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New Member
United States
23 Posts |
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Bedrock of the Community
United States
94367 Posts |
I'm not seeing any images.  to the CCF! |
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Bedrock of the Community
Canada
21596 Posts |
I see images but they look like some sort of screen or filter which have nothing to do with US modern coins.
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Moderator
 United States
34397 Posts |
Right. I think that what @humble is saying is that these four grids or whatever are what he/she doesn't know how to identify. Added: Just spit-balling here, but I wonder if these screen aren't for use with a 1970s era cathode ray tube or oscilloscope.  Are they a few inches across? "If you climb a good tree, you get a push."
-----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed."
-----King Adz
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Bedrock of the Community
United States
94367 Posts |
Okay, I'm just seeing some large blank squares.  |
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Pillar of the Community
United States
7617 Posts |
They look like photo masks used to make discrete semiconductors. (Sort of like a negative in photography). They appear to be what we called "emulsion masks" and we were lucky to get 50 quality contact prints with them back then. After use they were usually throw away or scrapped for recycling.
As far as semiconductor processing they would be considered antiques by today's standards since they are dated in the 1970's. I haven't seen any of these in at least 40+ years. We quickly went to chrome on glass to increase mask life and as devices got smaller and more complex.
As far as value? Might be worth a few bucks to a collector of semiconductor processing history.
They bring back a lot of memories! Thanks for sharing!
Edited by westernsky
12/12/2021 01:17 am
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Bedrock of the Community
United States
10284 Posts |
I was hoping for coins but I guess there were 4 square things in with the coins?
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New Member
 United States
23 Posts |
indeed I did find a date on something in the box that was in the 70's. wow ty for the information!
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New Member
United States
23 Posts |
are we also thinking that 6-18-70 is a date?
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Rest in Peace
United States
18456 Posts |
Looks to me like U.S.Navy pilots photographs of recent UFO activity . Could be a rare find if these were top secret pics and not released to general public .  |
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Bedrock of the Community
United States
19138 Posts |
Maybe we're being asked to grade image calibration graphics.
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Pillar of the Community
United States
7617 Posts |
Yes, the date is when that particular mask was made.
2048 is most likely the device number.
Emitter, base, oxide removal and metal removal are specific masking/processing steps.
I'm surprised the manufacturers logo is not on the mask somewhere.
I'd venture to guess the owner of the coins probably worked in the semiconductor industry at one time and he/she just tossed these scrap masks into his stuff. I kept a few things (souvenirs) in my 40+ years in the semiconductor business, too!
Edited by westernsky
12/12/2021 6:50 pm
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Pillar of the Community
United States
982 Posts |
Part of used Covid masks?  |
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Pillar of the Community
United States
3848 Posts |
Hmm interesting... Can we see some coins from the garage sale?  Suffering from bust half fever. Want to learn how to attribute early half dollars by die variety? Click Here: http://goccf.com/t/434955Shoot me a PM if you are looking to sell bust halves. |
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Pillar of the Community
Australia
1610 Posts |
Quote:Can we see some coins from the garage sale?  Bit of a click-bait title, especially since posted in a coin forum.... Like when the pics on a DVD cover don't occur in the movie. |
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Replies: 14 / Views: 1,652 |
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Posted 12/11/2021 8:55 pm
