Author Topic: flexible interconnect, like in old HP41 calulator wanted  (Read 2014 times)

0 Members and 1 Guest are viewing this topic.

Offline r6502Topic starter

  • Regular Contributor
  • *
  • Posts: 130
  • Country: de
flexible interconnect, like in old HP41 calulator wanted
« on: April 11, 2024, 09:05:30 pm »
Hello all,

I'm looking for a high quality flexible interconnet system, like used in old HP41 calculators. In the calculators it was used to connect the keyboard and LCD to the processor board. It was in-between the 2 boards and pressed a little bit together, and  so the pads on both boards, that had a larger spacing than the stripes on the interconnect foam where connected. This works still after about 40 years.



It looks like a flexible PCB with gold plated conductor strips, placed on a flexible material may be silicone foam. Does somebody have an idea, where to bye this kind of flexible interconnect system or was this custom produced for HP? Any hint is welcome.

Guido



Science can amuse and fascinate us all, but it is engineering that changes the world - - Isaac Asimov
 

Offline Stray Electron

  • Super Contributor
  • ***
  • Posts: 2090
Re: flexible interconnect, like in old HP41 calulator wanted
« Reply #1 on: April 12, 2024, 02:06:58 am »
   The connectors in the HP-41 were made by Amphenol (IIRC!) specifically for HP but the strips were a generic product offered by Amphenol.  Years ago I talked to both the Project Manager for that program and the man that originally designed the connector and that holds the patent for them. They send me the mechanical drawings for the connector and a lot of related documentation and the last of the HP-41 connectors.  Sorry, but I don't recall their names but they were in the US. I think somewhere in the midwest. St Louis?  I later passed all of the docs and other stuff on to an HP collector so I no longer have any of it but you should be able to find the patent.
 

Online Kim Christensen

  • Super Contributor
  • ***
  • Posts: 1402
  • Country: ca
Re: flexible interconnect, like in old HP41 calulator wanted
« Reply #2 on: April 12, 2024, 04:05:14 am »
For an LCD you could use an "elastomeric connector strip" or Zebra strip. Though that's not as metallic looking as what you've pictured.
 

Offline artag

  • Super Contributor
  • ***
  • Posts: 1091
  • Country: gb
Re: flexible interconnect, like in old HP41 calulator wanted
« Reply #3 on: May 05, 2024, 10:37:44 am »
There's also anisotropic conductive adhesives, which seem to be replacing zebra strips in some applications such as high density LCD connections. They're adhesives (often in a strip form) that conduct up and down but not side to side.

This is achieved by filling them with conductive balls at a density that means they don't touch much, but when the adhesive is pressed into place it collapses in the direction of the pressure. So the lateral spacing doesn't change, maintaining insulation,  but the vertical spacing is reduced making a tower of connected balls in that direction.
 
The following users thanked this post: Kean


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf