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Punch - Through Tablet Computer Keyboard

The Problem With Tablet Keyboards

Many people now have a tablet computer... either an ipad or some other such device who's principle user interface is a touch-screen, or touch pad.

However, in recognition of the fact that many still like to use a keyboard to type (If, for instance, they use it as a business tool, or have other documents to type at length), many have made keyboards available that can be attached to these devices.

In order to keep the overall profile of the tablet slim, and light (in keeping with one of the main reasons for buying such a computer of this form factor) these keyboards are rigid, and either operate by means of capacitance (the sensitivity to the proximity of a finger to the key(s)), or have a very shallow key “action” indeed, which doesn't offer the full action of a traditional keyboard... that is, the key doesn't depress to the degree, and with the corresponding positivity of a traditional computer keyboard key being pushed in until it strikes “home”.

For those like me, who prefer a more tangible experience when typing, as with the traditional, or conventional keyboard, the new touch-screens, or attached keyboards do not offer a sufficiently satisfying experience, to the point that I (and others) would not contemplate buying a tablet computer.

The Punch-Through Keyboard

To remedy this deficiency of the tablet computer, and without compromising the point of such a device, in terms of it's profile, I have considered how such a keyboard attachment could be made that would offer full functionality, with regards to the action of the keys, and which provides that more tangible experience...

The solution I have come up with is the concept of the “Punch through Keyboard”, with “Punch”, or “Strike-Through keys”.

This idea is best conveyed by first considering how a conventional keyboard (and keys) works in it's operation, and how the attempt to replicate this in these attachments for tablets has not worked.

A conventional keyboard functions by virtue of the key, being a rigid plate, or platelet, mounted on a spring, or springy material (silicone or rubber), being depressed to close the gap between the bottom of the key, where a piece of metal is situated, and the circuit board, which underlies the keyboard key arrangement... This metal plate makes contact with the circuit board, allowing a particular circuit (That corresponding to the particular key pressed) to be completed which signifies the chosen key in the computer software, and then displays that character on the screen.

However, this mechanical process is accomplished by a vertical action, of the key contact to the circuit board, as it is pressed down onto it, by the finger pushing on the key; And this is also the fundamental design fault of tablet keyboards, in the designer's attempts to replicate this functionality in the peripheral keyboards they have created for the tablet, they are attempting to accomplish two contrary objectives at once:

...To reduce the profile of the keyboard (and thereby reducing the depth of action of the keys)

…..And yet to create a keyboard who's design requires a vertical depression of the keys.

This, I believe, is nothing more than a “hang-over” from designs for conventional keyboards, as it is the accepted, or conventional manner of design to attempt to fulfil a need that people have expressed for a form factor which was never meant to accommodate it... and as such, is simply a habit of design that has been unthinkingly tacked on to a new concept, without having really had much thought applied to the fundamental concept of a keyboard for such a device, other than, how can we “square the circle”, or bash the proverbial square peg into a round hole.

Nevertheless, I believe this can be remedied by simply permitting the keys to be struck through the back of the keyboard, rather than simply meeting the circuit, and by extension, the back of the keyboard...

….this is done by not having a back to the keyboard at all!

So what of the circuit board, the circuits, and the key mounting?

And this is where I propose what may be called a paradigm shift, in terms of how such keyboard designs operate:

The key circuits are not completed by means of a vertical action of one contact to the circuit, but by means of a contact being closed laterally to a circuit designed to receive the contact from the side.

Think of each key being arranged like several trampolines in grid formation; Each suspended on all sides by springs (or equivalent fixings or materials) from the edge of the key, to a wire frame through which the key can travel, and which contains the circuits. The key, being depressed, pulls these springs, and the pulling of these draws the contact from an open position, to close against the frame, and circuit (1).

Mouse/Track Pad (2)

To incorporate a track pad, or some equivalent device that performs the function of a mouse, this method can also be adapted to work, by having a larger, track pad sized area, which operates on the “Gimble” principle...

That is, this surface area can be depressed on one side in order to move the mouse pointer that direction, and the degree to which it is depressed, relative to the other side, determines the distance or speed at which the mouse pointer on the screen moves. Essentially, this area is rocked around at any point, which takes “coordinates” of relative depression from around the edges to determine where the pointer moves, and how far and fast.

Backing Plate (3)

There is of course one final aspect of this keyboard which must be considered in order for it to be able to work at all (And of course, is a partial contradiction of what I said earlier... but only in respect of one of it's positions):

The keyboard, when opened away from the touch-screen/tablet, must be suspended, or elevated to some degree from any surface on which it rests, in order to accommodate the action of the keys moving through the back of the surface level of the keyboard.

For this, I think a second sheet of material can provide the backing plate for the keyboard, and which, when the keyboard is closed against the tablet, is shut tight to the keyboard key surface, so as to reduce the profile of the overall keyboard, with a minimal thickness (In keeping with the desire to maintain a slender tablet profile), but which operates like a draw bridge when opened, as perhaps, the angle of the keyboard to the tablet can pull small strings, or some such, that open a gap between the keyboard keys surface, and this backing plate, which can then rest on any surface on which it is placed, and so accommodate the action of the keys.
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  • quique77

    I believed the same. I only think now that you can use an special stick to touch the screen, but you don´t need the small stick with the punch keyboard. Good idea. You have my vote.

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