Transparent conductor on transparent plastic film?

In summary: I'm not aware of UV bulbs you can swap with the one in your video projector, those bulbs are something like 400V and draw specific current I think.There are also UV LED based projectors for industrial usage but are not cheap as are not manufactured in such high quantities to lower production cost.
  • #1
kekkked
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Need two transparent conductors in an arrangment like this on a transparent plastic film. Such as ITO on PET. But it doesn't have to be ITO necessarily.
There are going to be much more fingers and size of the lanes and their gaps are going to be sub milimeter, so hand drawing is out of the question.
Will be running few milliamps and about 8 VDC.
Size of the whole film is going to be 10 cm x 5 cm max.

Since I need to run dozens or maybe hundreds of tests with different widths, gaps and arrangments, I hope there is a way to print conductive material on a PET or similar transparent film at home, such as with a modified laserjet or inkjet printer, or a modified mini CNC.

Is there anything like this available, what can/should I use for the transparent conductive "ink" and the film and what should I use to get my drawing from a digital bitmap or vector film to a real film?
 

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  • #2
You can etch ITO films. For example:
https://www.researchgate.net/post/Can_anyone_please_recommend_a_process_to_etch_ITO_film

I would suggest finding an HCL photo resist and transfer your image optically. A photo enlarger can be used in reverse for this if you can't find a suitable photo reducer.

BoB
 
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  • #3
More info please on tranfering the image optically. I have a bright video projector (5000 lumen) and a visible light (445 nm, 520nm, 635nm ) laser beam scanner but not sure what needs to be done here.

I saw that page earlier today but don't see how you can cut a mask from a kapton tape with sub millimeter sections.
 
  • #4
You coat the film with a resist and cure it with light. The pattern is made by projection.

An example:
https://www.allaboutcircuits.com/projects/diy-pcb-photolithography-microfeature-fabrication/

The uncured areas are washed to expose the underlying material you want to etch. You can use this to plate metal electrodes as well.

BoB
 
  • #5
Very interesting! A single-chip XGA resolution (1024x768) 2000 lumen video projector can be bought for less than $200, then the color wheel taken out as well as the UV filter. This makes a grayscale projector bright enough for the projection to feel warm to the hand and can be focused to small few inch sizes.
Lamp will last for more than 1000 hours.

I'm pretty sure it won't work with cheap chinese LED or portable LED projectors as those LEDs do not produce light in the UV spectrum.

A laser galvo projector could also be built with a UV diode module for $400 which would probably cure it faster but would need specialized software to operate. Pretty much a stereolitography 3d printer without the Z axis.
 
  • #6
Some resists can be cured with white light.

Depending on what type of glass the lenses are made out of you might be able to replace the bulb with a UV LED.

If it comes with some type of discharge bulb you may be able to remove a UV filter to increase your short wavelength output. Filtering out the longer wavelengths might help with your sharpness.

BoB
 
  • #7
If white light only consists of a single wavelength red, green and blue lights, such as 450nm, 520nm and 635nm? I think that's how LED projectors and 3LCD and 3DLP projectors work, the former only generate those wavelengths to begin with, the latter filter out green, blue and red wavelengths from 3 white light sources, or extract red, green and blue light from the white light with a color cube.

But yeah except for LEDs you can remove the UV filter and optionally the red, green and blue gel filters and get UV.

Then few dielectric mirrors could be used to reflect the other wavelengths besides UV.

This sounds like too much work to just get UV light but I'm not aware of UV bulbs you can swap with the one in your video projector, those bulbs are something like 400V and draw specific current I think.
There are also UV LED based projectors for industrial usage but are not cheap as are not manufactured in such high quantities to lower production cost.

EDIT: Would also be pretty funny to find out you can use a transparent conductive ink with an inkjet printer.
 
  • #8
kekkked said:
If white light only consists of a single wavelength red, green and blue lights, such as 450nm, 520nm and 635nm? I think that's how LED projectors and 3LCD and 3DLP projectors work, the former only generate those wavelengths to begin with, the latter filter out green, blue and red wavelengths from 3 white light sources, or extract red, green and blue light from the white light with a color cube.

You will want to find one that uses a single white light source. If you get one and it is using individual color LED sources then you will need to find a resist that works with one of the wavelengths available. That will probably be more difficult than using a broad spectrum lamp.

kekkked said:
This sounds like too much work to just get UV light but I'm not aware of UV bulbs you can swap with the one in your video projector, those bulbs are something like 400V and draw specific current I think.
There are also UV LED based projectors for industrial usage but are not cheap as are not manufactured in such high quantities to lower production cost.

You can find directions online to replace the lamp of a projector with an LED. These high power white LED's come in standard sizes. Often you can find UV ones in the same mounting styles. They run at similar voltages as the white ones. The instructions will be the same except you will want to identify any UV filters and remove them.

Before buying the LED you might want to get several small ones of varying wavelengths and test to see how badly they are attenuated by the optics. You may end up needing to use a deep blue or violet one instead of UV.

BoB
 
  • #9
  • #10
I don't mean to be rude but I get this a lot. Googling "scientific evidence for santa claus" returns 500 000 hits, doesn't mean any of the results is usable. That's just how google works, even when it finds real useful pages it's just the first one-two pages of its list tops. I went through 2 pages of results and all were scientific/research articles, went through them and found nothing.
If you found a conductive ink as a readily available product in the google results which claims to be usable with inkjet printers please post here and I'll apologize for being blind.
 
  • #11
It does require some digging. I read the several of the sites on the first page of results and gleaned most of these going only one or two levels from Google. I got tired of looking in the middle of page 2 Google results.

https://www.agfa.com/sp/global/en/binaries/IJ1005-2013v1.1_tcm611-86919.pdf
https://www.inkworldmagazine.com/us-ink-directory/
https://www.alibaba.com/product-det...?spm=a2700.7724838.2017115.155.495040c4mDimBg
http://www.t-ink.com/products/touchcode/
https://www.nanogap.es/
http://www.sunchemical.com/t-sun/

Many links further down the page on this one.
https://www.inkworldmagazine.com/is...e-growth-in-flexible-and-printed-electronics/
 
  • #12
I'll have to email each company and ask if their inks work with inkjet printers. Ill post my findings here.
Second question is whether the ink will stick to a transparent film such as PET instead of paper.
T-Ink and Sunchemicals are the same I think.
 
  • #13
Nonw of the companies responded back about inkjet printer compatible transparent conductive ink. One company replied they have silver nanowire that can be used for making an opaque conductive inkjet ink but couldn't provide info how to create such a mixture. Thats all the info I got.
 

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