Editing Ergonomic keyboard (section)

==Features==
Like [[:Category:Keyboard form factors|keyboard form factors]], there are no standards in terms of what would be defined as ergonomic keyboard except as otherwise explicitly stated by the vendor/manufacturer or otherwise the design differs from the conventional keyboard shape.

Various features listed below by their common names are often proclaimed in research literature and the keyboard community as being "ergonomic" features of a keyboard.
Better ergonomic keyboards tend to incorporate multiple "ergonomic" design features, and are often also more adjustable to better cater to different individuals.

===Split===
A '''split''' keyboard has its keys physically separated into two halves: one for each hand.
Splitting is a prerequisite to several other features described below.

The term is sometimes used to refer to when the two parts are not physically linked.

<gallery widths=250 heights=187>
File:Cherry G80-5000 Full View Open.jpg | [[Cherry G80-5000]] is split with {{key press|6}} on the left side
File:Apple Adjustable front.JPG | [[Apple Adjustable Keyboard]] is split with {{key press|6}} on the right side
</gallery>

All split keyboards assign the letter keys to hands according to the [[Touch typing]] school, but there is no consensus about where to split the numeric row: Should {{key press|6}} be on the left or the right side?
On many typewriter-[[Staggering|staggered]] keyboards, such as the [[Microsoft Natural Keyboard Elite|Microsoft "Natural Keyboard"]], the key is on the left.
However, if the numeric keys are considered part of columns (which would be natural on a [[Staggering#Columnar layout|columnar]] keyboard) the key is on the right side.
Very few keyboards, including the [[Kinesis Evolution]], have {{key press|6}} on ''both'' sides.

===Tenting===
'''Tenting''' is having '''lateral inclination''' of each half of a keyboard so that if they were together they would resemble a ''tent''.
Another term uses the analogue of a ''house gable'': '''gable angling'''.

The purpose is to reduce ''forearm pronation'' (palms facing down), and to instead get more natural wrist angles (palms more vertical).

Only few keyboards allow the tenting angle to be adjusted freely without steps: examples include the [[Goldtouch Adjustable Keyboard]] and the [[IBM Adjustable Keyboard|IBM Model M15]].
Some fully split keyboards tend to allow tenting adjustment using different feet or risers.

<gallery widths=250 heights=187>
File:Tenting.jpg | Three tented IBM Model M15 keyboards
</gallery>

More [[:Category:Vertical keyboards|extreme examples]] have (or can be adjusted into) a fully vertical 90° angle.

===Separation and angling===
'''Hand separation''' means having the left and right hands' parts a distance apart from one-another.
Having an '''opening angle''' between the halves, means that they are rotated apart around an origin located above the keys.

The purpose of separation/angling is to avoid:
* ''ulnar deviation'' — where a wrist is rotated outwards in an unnatural angle, and
* tension in arms and shoulders, by catering to the natural distance between shoulders

There is no standard of where the origin of opening rotation would be located, so the opening angles of different keyboards are not always comparable.

<gallery widths=250 heights=187>
File:Kinesis 130e Essential.jpg | [[Kinesis Contoured]] keyboards have fixed hand-separation but no opening angle
File:Unikey KB-7001 -- top.jpg  | [[Unikey KB-7001]] has a fixed opening angle.
File:Ergodox1.jpg               | By being fully split into two separate halves, [[ErgoDox]] allows both hand separation and opening angle to be adjusted
</gallery>

===Negative slope===
Some keyboards can be sloped forwards ("North") instead of towards the user.
This is to make it easier to hold the wrists straight.
A negative slope is considered especially suitable when the keyboard is lower than the elbows, such as when standing.

A few keyboards have adjustable feet in the front for this purpose.
Some keyboards have retractable legs for this purpose.
The [[Microsoft Natural Keyboard 4000]] comes with a detachable riser to place under its front.

Alternatively, there are keyboard trays that can be adjusted to lean forwards.

===Hand shape===
Some keyboards have the keys physically arranged to better resemble the shape of a hand, at least compared to standard [[QWERTY|typewriter layout]].
This is primarily to reduce finger movement, but the keys tend to be also positioned so as to reduce ulnar deviation.

A keyboard with [[Staggering#Columnar layout|staggered columns]] has a column for each finger, with the offsets between columns corresponding to the relative lengths of the fingers and/or the position of the knuckles.

The [[Staggering#Symmetric_stagger|symmetric stagger]] layout is considered more ergonomic than the standard typewriter keyboard primarily through reducing ulnar deviation, but the columns for the middle, ring and little fingers are offset against each-other somewhat corresponding to the fingers' relative lengths also on both hands.

<gallery widths=250 heights=187>
File:NEC PC-8801-KI -- top.jpg | [[NEC PC-8801-KI]] has ''staggered columns'' for typing Japanese using the [[M-system]] input method
File:Mtron1.jpg | [[µTRON]] has columns laid out in a ''symmetric staggered'' layout
</gallery>

Note: So called [[Staggering#Matrix_layout|ortholinear]] keyboards such as the [[TypeMatrix line|TypeMatrix]] are an ''anti-pattern'' in this aspect, but many ortholinear keyboards are ergonomic in other aspects, such as having hand separation or even being fully split.

===Economic layout===
Statistics based on text and/or words in a target language have been used to arrange keys so as to minimise the amount of necessary finger movement — relative to a [[home row]].

{{main|Ergonomic keyboard layouts}}

The most popular such layouts in use may be [[Dvorak]] and [[Colemak]].
The first ones had appeared in the late 1800's not long after the first typewriter had been invented.

Some keyboards have also purposefully physically omitted the numeric row, so as to minimise finger movement away from the home row. Others have the [[function keys]] overlaid on the numeric row, or moved left purposely to avoid having to reach, or to encourage movement of the wrist to avoid strain from holding it static.

===Light key switches===
Use of lighter key switches could reduce finger strain, but on the other hand a key that is too light would more easily be pressed by mistake. Some keyboards such as the [[Key Tronic#ErgoForce|Key Tronic ErgoForce]] and some variations of the [[Topre Realforce]] have ''variable weighted'' keys, with the key [[weight]] for each key being adapted to the strength of that finger.

If the user can't tell where actuation happens, that could also lead to finger strain. Therefore key ''feedback'' is often also considered an ergonomic aspect. Feedback could be in form of [[Force#Tactile|tactile feel]] and/or a click sound, while many users would be content with consistent key feel or a distinct [[bottoming out]] after actuation.
The [[Kinesis Contoured]] has a built-in electronic speaker for keyboard click, which can be turned off.