Silent keyboard and key structure thereof

A silent keyboard comprising plural key structures, each key structure comprising:

• a keycap to be pressed, wherein the keycap comprises a bottom surface and a protrusion edge, and the protrusion edge is disposed on a periphery of the bottom surface;
• a buffering layer disposed on the bottom surface and the protrusion edge, wherein the buffering layer comprises a flat part, a raised part and plural coupling parts, and the plural coupling parts are protruded from the bottom surface;
• a stabilizing element located under the keycap and pivotally coupled to the plural coupling parts, wherein the stabilizing element is a scissors-type connecting element, a stabilizer bar, or an assembly of a scissors-type connecting element and a stabilizer bar;
• and
• a supporting plate located under the keycap, and comprising a key seat, a supporting surface and plural recesses, wherein the plural recesses are aligned with the corresponding coupling parts,
• wherein while the keycap is moved toward the supporting plate, the flat part, the raised part or the plural coupling parts of the buffering layer collide with the key seat, the supporting surface or the corresponding recesses, and the flat part, the raised part or the plural coupling parts are subjected to deformation.