Layer-structured, open-design keyboard

A layer-structured, open-design keyboard, comprising a main body and a tray attached to the main body from below, the main body having key mechanisms and keycaps mounted on tops of the key mechanisms;

• the main body including an upper-layer plate, a middle-layer plate, a circuit board, and a lower-layer plate arranged from a top to a bottom of the main body successively in a spaced manner, so as to define three clearance spaces that communicate an interior of the main body with an exterior of the main body;
• the key mechanisms being installed on the middle-layer plate, the key mechanisms having bottoms thereof inserted into the circuit board, and the keycaps being exposed at a top of the upper-layer plate;
• and
• the tray defining an accommodating chamber that receives therein an IO board electrically connected to the circuit board;
• wherein the upper-layer plate is fixed to the middle-layer plate by means of first screws, and the lower-layer plate is fixed to the middle-layer plate by means of second screws;
• and
• wherein the main body further comprises a frame plate that frames the circuit board peripherally and is fixed to the middle-layer plate or the lower-layer plate by means of third screws, in which the upper-layer plate, the middle-layer plate, the frame plate, and the lower-layer plate are arranged from the top to the bottom of the main body successively in the spaced manner.