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Electronics => Projects, Designs, and Technical Stuff => Topic started by: alank2 on February 07, 2014, 02:00:58 pm

Title: What would be a good clear adhesive for this?
Post by: alank2 on February 07, 2014, 02:00:58 pm
Hi Everyone,

I love LED displays, segments and matrix, etc.  One thing that is often annoying is that when off, the led looks different than the background color (where there are no LED's).  I notice that some have a darker background and some have a medium gray background (trying to be closer to the color of the LED when off), etc.

If I get some material that is tinted like you see for the covers of VFD displays, etc., is there an easy way to glue this directly to the top of a led module?  I'm thinking about a clear type adhesive that wouldn't get in the way of visibility.  Maybe you could cut a small square of the tinting material out and then roll an even sheet of adhesive on it, etc.  Any other ideas?

I've tried some car window tint that I got from a company who does it and it is thin, fills in the bumps of the LED's, etc.  It does make the LED and background surface look the same, but isn't flat and professional looking...


Title: Re: What would be a good clear adhesive for this?
Post by: staxquad on February 07, 2014, 02:41:07 pm

Lens cement could be a possibility,  Canada balsam dissolved in xylene.

Title: Re: What would be a good clear adhesive for this?
Post by: calzap on February 07, 2014, 04:07:08 pm
Trying to adhere two flat (or tangential surfaces) and maintaining transparency can be tricky.  Biggest problems are air bubbles and Newton's rings.  There are lots of tricks to avoid these (vacuum chambers, pressure chambers,  rollers, clamps, ovens, etc.), and the ones to use depend on the chemical and mechanical natures of the two surfaces to be adhered and the equipment available.  Good luck if any of the surfaces are fluorocarbons or polyallomers (polyethylene, polypropylene, etc.).    If an air gap is allowable between the two surfaces, then the process is simpler.  You can use perimeter blobs or ridges of thick adhesive, like hot snot or silicone, or a solid frame of metal or plastic with mechanical fasteners.  Tinted acrylic sheet would be good choice; it's readily available in lots of colors and thicknesses.

Mike in California