Transparent clear PCB manufacturer? - Page 1
Forum section: electronics / projects

author: daqq
author_rank: Super Contributor
timestamp: June 29, 2019, 06:57:31 pm
content: Hi guys,For a weird application I need a transparent clear PCB, preferably 2 layer, not particularly high tech (OK with 0.3mm feature size), preferably includes solder mask, can do without. I am OK with using a lower temperature solder.Ideally it would be on glass-ish or a similar material, but it can also be flexible. I think I remember a thread here some time ago when some guy was building a LED cube using such a PCB (flexible, 2 layer I think), but for the life of me I can't find it.Any suggestions? So far I've found PCBs on transparent alumina, but the pricing for those was ~4k just for the tooling and an LARGE price per board.Thanks,David

author: Berni
author_rank: Super Contributor
timestamp: June 29, 2019, 07:04:11 pm
content: Well there is a screen printing on plastic technology that is used for making keyboards. But that stuff is not meant for soldering at all, likely needs conductive glue to make a connection.For this its the vias that are the problem. You can laminate regular glass with copper foil and etch it into a cirucit, but drilling tiny holes in glass is not easy, nor it plating those holes in a DIY circuit etching setup.

author: daqq
author_rank: Super Contributor
timestamp: June 29, 2019, 07:07:49 pm
content: Thanks Berni. I've looked into that. There are manufacturers that will print (various means) conductive stuff on PVC (even polycarbonate), but, as you've said, soldering is an issue.Worst case scenario, I can do without 2 layers, but if at all possible, 2 layers.

author: branadic
author_rank: Super Contributor
timestamp: June 29, 2019, 07:21:51 pm
content: If you were able to reduce the design to 1 layer it is possible to use glass and deposite Cr, Ni, Au on it that can be soldered. Therefore a dry resist is laminated to the glass and processed with direct imaging, afterwards PVD is used to get the layers on it. After lift off you have a one layer circuit on glass. Interested? Contact me.-branadic-

author: hv222
author_rank: Regular Contributor
timestamp: June 30, 2019, 03:23:38 pm
content: Vias on keyboard transparent foil are possible. If you don't need a high current nets or RF it should work with components mounting with conducting glue. Some ceramic capacitors with flex termination require conductive glue mounting so there should be companies that can do a pick and place process with conducting glue. Problems starts when you need also transparent nets. Then I will contact with companies that making customs LCD's or touchpanels.

author: Benta
author_rank: Super Contributor
timestamp: June 30, 2019, 03:49:48 pm
content: Instead of soldering, you could consider conductive adhesive.

author: Gyro
author_rank: Super Contributor
timestamp: June 30, 2019, 06:30:40 pm
content: I remember a Practical Electronics article from the '70s, maybe earlier, about making conductive glass at home.Irrc, it used a small pile of Stannous Chloride which was heated on a kitchen hotplate under the edge of a sheet of glass which was raised a little above the heated surface on glass corner supports. Apparently the vapour left a tough layer of Stannous (Tin) Oxide deposited on the underside of the glass. I think a fan was used to provide uniform coverage.The article suggested several uses. These included switched opaque LCD panels, resistors, (masking off non-conductive areas with a glass/water slurry), and electroplating with copper to make conductive traces.Such plated traces would probably take solder well, assuming the glass would take the localized heat - substitute SMD, solder paste and reflow these days I suppose.The process was probably toxic as hell in a confined space however.

author: Berni
author_rank: Super Contributor
timestamp: July 01, 2019, 05:29:04 am
content: Well you can buy such conductive glass under the name of "ITO glass" even on ebay. And can be etched with a UV resist process like PCBs.But if the aim is to just put a metalized layer onto a piece of glass then you can do it easier by chemical reactions that deposit metal on walls. There is a method with silver nitrate that is very easy to do at home, its a popular method for turning glass into mirrors. You could then use this tiny silver layer to then electroplate a thicker layer of copper on it. Since silver and copper are from the same family and love to alloy together it should stick to it nicely and you can build up the copper as thick as you want.It sounds like it should survive a reflow soldering process just fine. It would likely need to be cooled down pretty carefully tho to make sure the glass doesn't shatter.

author: capt bullshot
author_rank: Super Contributor
timestamp: July 01, 2019, 06:07:51 am
content: This is the thread, I believe:https://www.eevblog.com/forum/projects/kcube-led-cube-design-revisited/He's talking about transparent flex PCBs

author: ebclr
author_rank: Super Contributor
timestamp: July 01, 2019, 08:12:27 am
content: For low current, LCD factories may help, an LCD have a transparent conductive layer

author: CJay
author_rank: Super Contributor
timestamp: July 01, 2019, 08:26:34 am
content: Stick a sheet of self adhesive copper to it, etch as usual or use a vinyl cutter?And oooh, that project with the flex PCBs is going to be great once it's finished.

author: daqq
author_rank: Super Contributor
timestamp: July 01, 2019, 11:39:34 am
content: Thanks for the great suggestions guys!The thread capt bullshot was the one I was looking for!I was hoping to avoid all of the 'homebrew' stuff. I'm sure it's possible, I even found a few articles ( such ashttps://hackaday.com/2016/07/18/cnlohrs-glass-pcb-fabrication-process/) on the topic, that gave great result,s but I want to avoid these kinds of extra steps if at all possible. I've thought about various DIY ways, but it was all unreasonably complicated and I don't want to deal with that.I looked into the silver nitrate method, but to the best of my knowledge, the design would have no staying/adhesive power and the insanely thin amount of metal would probably be melted into the solder.One of the sillier ideas I had was to have a water jet (or similar) cut out a copper pattern from thin sheet metal and these would be then glued on to the substrate (basically a nastier version of CJays vinyl cutter suggestion).QuoteYeah, I know, but it can't be soldered to the best of my knowledge.