Scanning optical keyboard

An optical keyboard having keys and being suitable for use with keyboard-scanning means including a plurality of switchable light sources and a plurality of light receivers, the keyboard comprising:

• a generally flat optical block having a top face and a plurality of sides, the top face being intended to cooperate with the keys;
• a plurality of light injection inlets and a plurality of light detection outlets in the block respectively for coupling to the light sources and the light receivers of the keyboard-scanning means;
• and
• a plurality of key-actuated elements and pairs of unobstructable light ducts in the block, each key-actuated element cooperating with a corresponding pair of unobstructable light ducts and being operable to selectively couple and decouple said pair of light ducts;
• one of the ducts in each pair being an inlet duct connected to a light injection inlet and the other duct in each pair being an outlet duct connected to a light detection outlet in such a manner that each key-actuated element embodies an intersection of an inlet/outlet matrix in which each distinct matrix intersection is defined by a unique inlet/outlet pair, thereby making it possible for keyboard-scanning means, when used with the keyboard, to identify key depressions by applying a signal successively to each of said light injection inlets and by observing the state of all of said light detection outlets after each signal application;
• said light injection inlets and said light detection outlets all being disposed along the same one of the sides of said optical block, thereby facilitating coupling between the keyboard and keyboard-scanning means.