An optical keyboard is a device that wirelessly connects to a computer and serves as a data input device, similar to what a traditional keyboard may do. With the focus of many computer accessories going wireless, this keyboard offers that advantage as well. In addition, another type of optical keyboard is one that projects a virtual keyboard onto a flat surface, though the term optical keyboard is not widely applied to that type of hardware.
In actuality, the term optical keyboard is a misnomer, likely coming from the fact that wireless computer mice are referred to as optical mice. In computer mice, the term optical does not refer to the connection technology between the mouse and computer, but rather the tracking technology in the mouse itself. A wireless keyboard is usually connected to a computer via an infrared connection, much like a remote control works, or via radio frequencies. In some cases, a Bluetooth® connection may be used, giving rise to the term Bluetooth® keyboard. In some ways, given the infrared connection, the term optical keyboard could still technically be considered correct.
For whatever reason, the phrase optical keyboard is often used when referring to a wireless keyboard. In those cases, it is generally understood that the term optical has taken the place of the term wireless. Also, wireless keyboards and optical mice are often packaged together, which may further reinforce the wrong term in some people's minds.
The advantage of a wireless keyboard is in its ability to be moved around, rather than be tied down to a radius of just a few feet around the main CPU of the computer, like a wired keyboard would be. This can be especially helpful when giving presentations requiring the use of a keyboard. In some cases, having a computer next to a podium is not practical. However, it may be easier to have a wireless keyboard at the podium.
A wireless keyboard, other than the technology connecting it to the computer, works the same as any other technology. Sensors detect when a key is pressed and sends that information along in the form of an electrical signal, which is then processed by the computer and displayed on the screen. The only thing different is how that signal gets to the CPU. Most wireless keyboards cost more than similar wired versions, but the cost is still affordable for many computer owners. Finding one for less than $30 US Dollars (USD) is generally not a problem.