This is NOT from a hardware hacking DIY/hobbyist/customization perspective.
Consider the commercial-volume/hardware-manufacturer/mass-production approach instead.
I am a teacher of Information/Computer Technology, and am now trying to get myself up-to-date on this particular topic. Not only so I can provide better answers to students, but also because as a computer enthusiast, these manufacturing details happen to feed my own curiosity.
I recently realised that each time the topic of “how keycaps are made” comes up, everything I say is actually based on the bulky-clicky keys of the 1980s desktop keyboards. These buttons are tough pieces of hard and thick plastic, grey or beige in colour, with typically a 1cm (quarter of an inch) or more depth. Letters or symbols were spray-printed on the top using chemically special ink, which was then heat-treated to stick and solidify for maximum endurance. This view on keycaps manufacturing is obviously outdated.
Take a look at the computer keyboards around you today, and you will most certainly see thin laptop-style keycaps, even on a full-size desktop keyboard. They look ALMOST like a single sheet of thin plastic, with ALMOST no depth, no hollow underside. Obviously there is some, but it is so shallow that this depth can hardly be seen. The base colour of the keycaps is now dominantly either black, or white. And on higher-end models the letter or symbol on top lits up in the dark. Not just fluorescent I mean, the key actually produces light. I believe the light source is under the keycap, but the keycap is designed in a way to allow some of that light to shine through, exactly where the letter or symbol is painted on the top. Hence the word “painted” is likely no longer accurate. And these are the kind of keycaps people today most likely come into contact with. Apparently not the old geezers like I am, who still type on their long-time favourite clicky keyboard, with the original connector doubly converted, first to PS/2, then from PS/2 to USB. My niece’s laptop has a keyboard with a key that also acts as a fingerprint reader. That key looks exactly like any other keycaps on that keyboard. So the plastic must be really thin.
I hope the community here includes people who know how these modern kaycaps are made, and they can get me updated on the details. The emphasis is on KNOW, and not on THINK. I can THINK of many ways the keycaps are produced. But I don’t KNOW which way it is actually done. For example, I can easily imagine the symbols being laser-engraved now, which would also burn away some of the thin plastic allowing light to pass through there in exactly that shape. But that would work for the white keys with black letters only, and most likely are not doable for black keys with white letters. Because they keycaps are so thin now, painted symbols are unlikely to be heat-treated. Instead, a transparent coating layer may be sprayed over. Some sort of film, to protect the painted top.
So, ideas I have many. Facts, I do not.
Here are some specific questions to guide you along the details I am interested to learn:
- What material, what kind of plastic is used as the base material?
- How is the keycap formed out of that base plastic? Is it still
hot-moulded? At what temperature? Or is it now cold-cut out with a CNC? Or maybe 3D-printed? - How is the symbol on top of the keycap put there? Is it sprayed
through a cut-out shape mask? Or is it more like ink-drawn/brush-painted along a defined line/curve? Or is it laser engraved along such a path? - How is the lettered top protected against wear? Coating film, heat treatment, burning the symbol in?
- How are the lit keys made? Are the symbol shapes to shine through cut/burnt
into the keycap, or is that thinner part actually produced at the time the keycap itself is formed?
I desire no trade secrets or patiented details. I am happy with the pieces you are allowed to share. Feel free to generalise. But stay accurate in what you do say. Please avoid naming brands, and do not evaluate how good or bad a particular product or manufacturer is.
- Do you need me to clarify any of my questions? Feel free to ask!
- Are you also interested in the topic I raised? Feel free to add your own questions in a comment!
