ErgonomicsAmbient room-light illuminating passive key surfaces is better for your eyes. That is more beneficial for you in the long run as you
progress through the years.
Blue light is especially bad, both outside and indoors. Piercing light in a dark room is especially bad.
I think it might have been TG3 who first made backlit Cherry MX keyboards — but for rugged and industrial purposes, such as in police vehicles, industry and other conditions where lighting is difficult to control. In those use cases, you don't use the keyboard for long periods at a time.
Modern mobile devices have light sensors that adjust the light output of the screen to ambient conditions. Modern screens with high-fidelity requirements for its contents instead
illuminate the surroundings to even out differences. Modern operating systems can even adjust the colour temperature of the screen to match the Sun's changing output throughout the day. I have never heard of any keyboard having any of this, except for side-glow.
StructureThe prevailing logical convention for placement of symbols on keycaps uses vertical positioning for Shift-key state and horizontal positioning for Alt Gr-key state. That is why symbols conjured without any modifier are in the lower-left corners and upper-case letters are in the upper-left corners. Keys that have the same meaning with or without Shift pressed have left-justified vertically-centred legends. (PS: notice the
two symbols on the Tab key)
Filco makes keyboards with Cherry MX switches. Cherry MX was not made for backlighting in the first place. The LED and its window are designed to be in the
front, for additional indicators, not for illuminating the legend surface. The orientation of the switch and the shape of the switch housing were designed together with thick-walled keycaps so that they fit together: if you change the orientation of the switch, the high-quality thick keycaps may not fit.
Backlit keyboards with Cherry MX are a hack: they tend to move the LEDs and legends around to illuminate letters only on the top half, centred horizontally, thus breaking the convention. They almost always illuminate quite unevenly. This means that some keyboards, such as those from Corsair have secondary legends that are not illuminated at all, and tertiary legends (Alt Gr) are often missing completely. Also, many keyboards have transparent switches, reflective key bottoms and insides of keycaps to make light more even — but which fail because the LED is still on one side and the key stem in the middle still obscures the light, and only produces extra light bleeding out the sides.
ChangeWhat backlighting can provide that is useful IMHO, is to use different colours on different keys, or even on different symbols, to show different configurations. But light emission needs to be analogous to how light is
reflected during ambient light.
What backlighting needs is:
* Ambient light sensors to adjust the intensity of the light to the surroundings automatically. I have only heard of laptops having this. This can be done on keyboard as well. I think this would be better done through
standardised system-wide systems that influence multiple peripherals at once.
* Blocking/evening out of unnecessary saturated blue light by default. Never heard of, but easy to do. Don't install blue LEDs, and block saturated blues in software and firmware.
* Switch systems that illuminate the whole key surface, i.e. the centre of the key and the whole of longer keys as opposed to one point on one edge. Not Cherry MX. Omron and Kailh have centre-illuminated key switches. Supplementary LEDs could be placed beside them for more illumination.
* Insulated light guide, to avoid light-bleed. Not Cherry MX. Opaque insulation around LEDs: both in switch and around supplementary LEDs.
* Keycaps that let light through its legends without struts (Not the norm, even for Cherry MX). Keycaps need to be double-shot moulded with both transparent and opaque plastic.
An older alternative type of night-time keyboard illumination would be to have a special-purpose light, such as the
Thinklight.
Or just mount a desktop lamp and light it.
Much easier.
