1. Field of the Invention
The invention relates to a keyboard assembly, more particularly to an ergonomical keyboard assembly.
2. Description of the Related Art
Referring to FIG. 1, a conventional keyboard assembly includes a plurality of keys which are arranged on a same plane, and an overall key surface formed on top of the keys is planar. When operating the keys of such an assembly, the user must place his/her hands in a working position in which palms and fingers lie on a substantially horizontal plane. In order to reach this working position, the user must turn or twist outward his/her elbows and wrists from their natural physical positions, and the palms, which normally face inward and towards one another and which are normally in a non-stretched convex state, have to turn to a downward facing position. Therefore, the aforesaid keyboard assembly is not ergonomically favorable to the user, and the user would easily become tired or even get hurt, especially, at his/her shoulders, elbows, and wrists, after working for a long period in an unnatural physical position.
There is another conventional keyboard assembly in which operating keys are divided into two groups (a, b) arranged in inclined positions in two separate areas, as shown in FIGS. 2 and 3, and in which an arched palm rest portion (c) is provided to support the hands of the user. This assembly permits the user to place his/her hands comfortably on the arched palm rest portion (c) in a natural physical position, without turning or twisting his/her elbows and wrists. However, since the key groups (a, b) are fabricated and are assembled separately, the manufacturing process of this keyboard assembly requires extra components and steps, thereby increasing the cost of production. On the other hand, as the overall key surface of each key group (a or b) is still planar and not arched, all of the keys must be hit in directions perpendicular to the planar key surface. As the hands have the fingers and palms thereof normally bending inward and as the fingers in their bending positions would have to move forward along directions perpendicular to an arched surface, this keyboard assembly is insufficient to satisfy the requirements for proper human operation and performance.