On the previous page, alternative arrangements of the keys in the main portion of the keyboard, such as the Dvorak layout, were discussed.
On earlier pages, exotic or specialized keyboards, such as those with mathematical symbols and the Greek alphabet, as used with some of the LISP machines among others, or the specialized keyboard used with APL, were discussed.
Let us look at an elaborate keyboard, such as this one shown on an earlier page:
A keyboard with so many keys would seem to be a specialized device. But it might have a multitude of different specialized uses. How might one indicate that its keys are being used for a particular purpose, depending on the application or operating system in current use?
The diagram below
illustrates how the portions of the keyboard used for function keys both in the original IBM PC keyboard and in the later 101-key keyboard lend themselves to having their purposes described on a cardboard overlay with holes cut in it for the places where the keys are.
Also, for keys other than the primary typing keys, the option exists to use a small, calculator-style, keycap. This creates space between the individual keys, and limiting the height of such keys can ensure that the space is easily visible.
The phrase that comes to mind here, however, is "picking the low-hanging fruit". It is also desirable to have the ability to change the legends on the keys in the primary typing area easily. How can this be dealt with?
One idea that has recently been tried is to make a soft rubber overlay for the keyboard. If the overlay is not a flat sheet, but has a molded cup for each key, then it is easy enough to press the part of the sheet over each key down when typing on that key.
Another idea that has been around longer, which permits setting up a custom keyboard layout to begin with, although it does not lend itself well to changing that layout periodically, is to make the keycap, or part of the keycap, for each key transparent, so that the key can be opened up, and a cardboard label inserted, and then the protective plastic cover returned.
Keyboard types with short production runs have often been mmanufactured using this principle as well, even if keyboard customization afterwards was not desired as a feature in itself.
The keys on many older manual typewriters were constructed with a metal collar holding down a plastic window over a printed label with the character for the key printed on.
People using APL/360 with the IBM 2741 could affix adhesive stickers to the front of the keys, in the manner shown in this illustration:
and the keyboard of the IBM PC extended the possibilities of attaching stickers to the keys of a keyboard through popularizing an important innovation.
The keycaps on the keyboards of many electric typewriters and nearly all typewriter-like computer keyboards usually have the form of a truncated pyramid, with a square base just short of three-quarters of an inch on a side, with curved, tapering sides that go to a square top that is one-half of an inch on a side.
That square top, however, was not flat; instead, to help guide the fingers, it was concave, its surface having the shape of a portion of the interior surface of a hollow sphere.
With the IBM PC, this was changed. The top surfaces of the keys still had a concavity to guide the fingers, but this time it formed part of the inside of a hollow cylinder. In this way, a label taken from a flat sheet of adhesive plastic could be bent to cover the top face of the key, which it could fit perfectly, because the surface of a cylinder, like that of a cone, is what is known as a reducible surface, one that can be bent without stretching to form part of a plane.
Other possibilities exist that have not been tried as often.
A keycap could be designed that consists of a square of transparent material, perhaps supported by a metal frame with legs at the four corners (which then join again to a plate underneath which pushes the central plunger for the keyswitch). Since the keys of a typewriter keyboard are in regular rows, an overlay could slide under those keys to identify them.
Such an overlay would look like a comb, and so, since it consists of multiple thin strips, it would be fragile. As well, this would work best if the keys had limited travel, and the keyboard was not stepped, so that the legend under the key is indeed easily visible through the key.
An attempt to illustrate this concept is made in the diagram below:
the yellowish straw-colored cardboard underlay in four strips is being slid from the left under the keycaps.
Another possibility would be to mount keys which were squares of transparent plastic on levers, the way that was done on a manual typewriter, except that the levers are bent as necessary to always pass around, and never under, the keys on rows further up. One could imagine a keyboard of this sort being made from glass instead of plastic, for more transparency, with levers of gleaming stainless steel, being offered by a European designer. The main technical problem would be making keylevers both rigid enough to serve and thin enough so that four or more of them could move freely in the 1/4" space between two keys on the top row. An overlay under such a keyboard could be moved freely so that its legends would be directly behind the appropriate keys in the user's line of sight.
Of course, the ultimate way to relegend a keyboard would be to do it electronically. by allowing each individual key to contain a display. A keyboard of this type has been announced as a forthcoming product by one company.
Copyright (c) 2007 John J. G. Savard