Abstract: This low profile key switch structure provides a substantial reduction in the height or thickness of a key switch as compared to conventional and other low profile switches. Substantial height reduction in key switch structures allows the size and thickness of notebook-type personal computers and the like to be similarly reduced. One feature of this low profile key switch structure is that unlike in conventional key switch structures the membrane switch and frame structures do not over lap to cause unnecessary height in the structure. Another feature of this key switch structure is that the frames are formed to include the free motion range limiters. The frames are further formed so that they may be embedded in the reinforcing base plate in such a manner that allows the height of the key switch to be further reduced. This low profile key switch structure is also designed to eliminate unwanted key top movement that often occurs in conventional and other switches when the key top is depressed.