Fiber optic keycaps

[Mandolin]

ENHANCING LED SUPPORT WITH FIBER OPTIC THREADS:

Currently, to make led compatible keycaps we have 2 options:
(1) To do a thin layer of resin for the light to shine through.
(2) Using a high refractive index material (>water ideally): mineral beads, clear resin.

It's good enough for eyes that are in straight line from the led at the base of the switch, however it doesn't work to illuminate effectively little parts of the keycaps of <2mm spots and or lateral sides.

What hasn't been done?: use fiber optic threads.

Method: at cast time, they should be pinched through the mold and bent towards the base of the keycap, where the led would be located, so they'd be included in the final cast.

Hypothesis: The clarity of illumination should displace poorer performing refractive materials as clear resins or even most crystals.

Uses: to illuminate front and sides of a keycap or accentuate tiny spots on it. If enough threads are grouped together, minor shapes could be achieved such as alphabet characters or little drawings, for instance. It could illuminate just the iris in the eyes.

Disadvantages: making holes in the mold and labor intensive process for just one keycap.

p.s.:I also posted it in my artkeycaps topic, but wanted to discuss it further and give ideas to other cap makers.

[Evo_Spec]

This could work too if you drilled a hole after casting and threaded the fibre optic thread through too.

[Mandolin]

This could work too if you drilled a hole after casting and threaded the fibre optic thread through too.

Good idea

That would be time/cost effective, but with the limitation of straight line path of the fiber optic and proper fiting. The weird results should come from twisting or slightly bending the fiber optic during casting to illuminate a lateral side on the body of the keycap, that'll shine as it had a led directly below it, instead of further away, with little to no loss in color intensity, that's the advantage of fiber optic cables.

[Evo_Spec]

This could work too if you drilled a hole after casting and threaded the fibre optic thread through too.

Good idea

That would be time/cost effective, but with the limitation of straight line path of the fiber optic and proper fiting. The weird results should come from twisting or slightly bending the fiber optic during casting to illuminate a lateral side on the body of the keycap, that'll shine as it had a led directly below it, instead of further away, with little to no loss in color intensity, that's the advantage of fiber optic cables.

This might be less time/cost effective but you could also drill 2 holes at different angles so where the 2 points meet will give a bend in the fibre optic thread, i imagine you couldn't do more than a 60° bend, maybe 90° if you really try but again, less time/cost effective.

[Mandolin]

This might be less time/cost effective but you could also drill 2 holes at different angles so where the 2 points meet will give a bend in the fibre optic thread, i imagine you couldn't do more than a 60° bend, maybe 90° if you really try but again, less time/cost effective.

even better! I like where this is heading.

[JinDesu]

Would the individual fibers be visible when lit up? I assume you can't literally get fibers in the exact size you need, so either you have to design around the fiber thickness or you have to run multiple fibers in parallel - at which point would they shine like one solid light source?

[Mandolin]

Would the individual fibers be visible when lit up? I assume you can't literally get fibers in the exact size you need, so either you have to design around the fiber thickness or you have to run multiple fibers in parallel - at which point would they shine like one solid light source?

I don't know :/, I think each individual fiber would be visible, unless a workaround is made such as including them in resin with a similar refractive index, so their perimeter wouldn't show so easily. It's basically how glass fiber rods used in root canals are made (Strassler, 2008).

It'd come with associated loss in light intensity, but it's possible.

[Cross section of glass fibers embedded in resin inside a dental fiber post]


Light transmission of dental fiber post. source.

[JinDesu]

If so, then I think either a surrounding resin of similar refractive index will help diffuse and remove internal shadows, or you can cast around it (like insect eyes perhaps).

[Mandolin]

If so, then I think either a surrounding resin of similar refractive index will help diffuse and remove internal shadows, or you can cast around it (like insect eyes perhaps).

I think so too. Both. If a dissimilar refractive index resin is used, it'd also work, but with higher light loss as it'd act as a optical diffuser.

Now I can think of only a few alternatives to do it, maybe there are more.
(1) Cast a keycap or modify one. Then drill a hole with the dimensions you're looking for based on your creative design in function of which parts should be illuminated, insert fibers to cover at least 50% of the diameter of the hole and pour the resin in between.
(2) Drill the section you want to illuminate for the fiber threads to go towards the base of the keycap, as in the example 1. Then considering the diameter or width of your holes, premix fiber optic threads with resin outside the hole, fit it and then fill the voids with resin.
(3) Mold and cast the holes in your keycap and build separately a custom fiber optic post that'll fit just perfectly. A limitation would be to do it in a straight path.

[berserkfan]

just one concern; the amount of work involved is really ridiculous. Are there other industrial methods worth considering? If you're doing one keycap it's not an issue but I can't imagine doing an entire keyboard.

[Mandolin]

just one concern; the amount of work involved is really ridiculous. Are there other industrial methods worth considering? If you're doing one keycap it's not an issue but I can't imagine doing an entire keyboard.

That's for an industrial engineer to answer, surely there must be a way.

I'm just exploring the limits of what's possible theoretically, and probably will do this myself in a prototype.

I enjoy working manually on a keycap to keycap basis, with no intention to do whole sets, so ridiculous things are good enough if they're challenging

Imitating fly's eyes caught my attention: so they'd shine beautifully in relation to the led light source, maybe a small prism in the middle of the fibers could diffract the colors in such way.
Small Optical grade prisms could be used: http://www.poci.com/micro-optics-components/micro-prisms.php

[GenKaan]

As long as esthetics are more important than quantity and you could make a profit from selling caps around $25-30 I say go bananas man

[berserkfan]

I really find his project exciting and interesting. I believe Mandolin will make far more money selling backlit 'clacks' (eg faces with fiber optic eyes) than he ever will trying to persuade us that his Model Ms have some magical crystal inside.

If Mandolin is good enough with his hands (and he seems to be) he could even consider an entire scene (eg a lighted up Christmas tree keycap with 8 lights). Keycap like that will wind up fetching more than whatever he tried to sell his super crystal Model Ms for.

[neverused]

One ghetto rigged way to test this would be fishing line. Bundle it up and cut the ends flush and you should be able to transmit light end to end much like fibre optics, though not quote the same quality but I can't say you'd notice with such a small surface area.

[Oobly]

I really find his project exciting and interesting. I believe Mandolin will make far more money selling backlit 'clacks' (eg faces with fiber optic eyes) than he ever will trying to persuade us that his Model Ms have some magical crystal inside.

If Mandolin is good enough with his hands (and he seems to be) he could even consider an entire scene (eg a lighted up Christmas tree keycap with 8 lights). Keycap like that will wind up fetching more than whatever he tried to sell his super crystal Model Ms for.

Sounds like almost as good a racket.

Diffusion is a good thing for backlit keycaps... You don't actually want directed light. Glare city. This "great" idea is just... not.

[Mandolin]

I bought online PMMA fiber optic strands in various widths (0.26 mm, 0.50 mm, 0.75 mm, 1.0 mm, 2.0 mm, 3.0 mm) to do some tests. I think it covers the full range of what could likely be done on a keycap.

[JinDesu]

I really find his project exciting and interesting. I believe Mandolin will make far more money selling backlit 'clacks' (eg faces with fiber optic eyes) than he ever will trying to persuade us that his Model Ms have some magical crystal inside.

If Mandolin is good enough with his hands (and he seems to be) he could even consider an entire scene (eg a lighted up Christmas tree keycap with 8 lights). Keycap like that will wind up fetching more than whatever he tried to sell his super crystal Model Ms for.

Sounds like almost as good a racket.

Diffusion is a good thing for backlit keycaps... You don't actually want directed light. Glare city. This "great" idea is just... not.

To be fair, it could be used artistically in some aspects. I can't really imagine the LEDs throwing light too far from the cap, so you could create a cap where the fiber threads are not pointing directly at the user - or as I believe Mandolin mentioned, you can bring the light from the LED to portions of the keycap that normally don't get lit as well.

For example:



I have the zerg key on the left and the bottom set of openings do not light up properly because my LED is on the top of the switch. If the keycap had fiber optics, it would be able to direct the light to those set of openings to evenly distribute the light.

[Mandolin]

yeah, PMMA optic fiber cables use consumer grade optics. They won't blind anyone. Maybe more exquisite stuff could do some harm. Glare city no no.

Even total internal reflection is present only in short distances from the light source and then degrades quickly. Sum to that there wouldn't be direct contact between the led and optic fiber thread embedded in the keycap. Brightness won't be critical, but you'd still get a nicer hue than with other methods. It has no risk to tear anyones corneas.

Talking about total internal reflection and flexibility of the acrylic cables, loss and scattering allows you to see light pass through the cable and the second, slightly adapt it to follow an intricate path. With glass/silica fibers you couldn't do that (but you'd get less signal degradation if you ought to do fiber optic eyes in a straight path). There are new microcrystalline super flexible plastic fibers that could also work. I'd look into those in the future.

If I were to do a heart on a keycap, I could do the superficial arteries with optic fiber threads, so they'd be selectively illuminated depending on the switches led source. It'd look as if bright liquid went through them, even if embedded in clear resin.

Maybe I'm wrong. Clarification from people with knowledge in this area is highly appreciated.

[Oobly]

Okay, good luck with the project. It may be possible to do a polycarbonate / ABS doubleshot mold with the polycarbonate forming the "light guide" (like the Cherry Legend Replica set alpha keys, but with custom "legend" mold designed from optical principles). Cost may be high, though. Also, It'd be best to design it with either switch orientation in mind (LED at the top or at the bottom, ie, 2 light source positions). I'd shoot an email off to Bob or Melissa at SP. I believe Melissa is on maternity leave, but Bob is answering emails.

[berserkfan]

Sounds like almost as good a racket.

Diffusion is a good thing for backlit keycaps... You don't actually want directed light. Glare city. This "great" idea is just... not.

I agree with you that it will suck for real users like me, who type all the time.

But face it, most of the buyers are gonna be kids who just like novelty and spend all their money on artisan caps. You can't type on a Brobot, Ironman, Gummyrot and what have you. For kids, cool and pretty far outweighs ergonomics or 'comfortable' to the eyes.

By all means direct all light to the ceiling, Mandolin. I bet some kids will Really like a keyboard that has laser like eyes shooting light all the way up.

[Mandolin]

http://youtu.be/o3X0xoX0obY
Quick test.

I used a bad casting, so ignore that.

[heedpantsnow]

Looks pretty sweet bro. Labor intensive, I presume?

[Mandolin]

Looks pretty sweet bro. Labor intensive, I presume?

yes, the bead holes need to be aligned precisely with pins when casting, it requires multiple pours, at least two, to remove the pins at and be able to close the mold, if you don't time it the beads could get vertically uneven. Then drilling the excess resin in the bead, toward the base of the keycap, fitting a cable, drilling it a bit more to have enough space for crystal clear resin, cutting it in the final extension, polishing both ends, embedding it in resin, and letting it set.

[heedpantsnow]

Looks pretty sweet bro. Labor intensive, I presume?

yes, the bead holes need to be aligned precisely with pins when casting, it requires multiple pours, at least two, to remove the pins at and be able to close the mold, if you don't time it the beads could get vertically uneven. Then drilling the excess resin in the bead, toward the base of the keycap, fitting a cable, drilling it a bit more to have enough space for crystal clear resin, cutting it in the final extension, polishing both ends, embedding it in resin, and letting it set.

Wow. But dang cool!