Abstract: A membrane circuit board includes a first membrane substrate, a spacer substrate, a second membrane substrate and a third membrane substrate. The first membrane substrate includes a first gas channel and a first conductive contact. The spacer substrate includes a first gas hole and a second gas hole. The second membrane substrate includes a second gas channel, a second conductive contact, a third gas hole and a fourth gas hole. The second gas channel is in communication with the third gas hole and the fourth gas hole. The second gas channel is in communication with the first gas channel through the first gas hole and the second gas hole. The third membrane substrate includes a third gas channel. The third gas channel is in communication with the second gas channel through the third gas hole and the fourth gas hole.

Abstract: A membrane circuit board includes a first membrane substrate, a spacer substrate, a second membrane substrate and a third membrane substrate. The first membrane substrate includes a first gas channel and a first conductive contact. The spacer substrate includes a first gas hole and a second gas hole. The second membrane substrate includes a second gas channel, a second conductive contact, a third gas hole and a fourth gas hole. The second gas channel is communication between the third gas hole and the fourth gas hole. The second gas channel is in communication with the first gas channel through the first gas hole and the second gas hole. The third membrane substrate includes a third gas channel. The third gas channel is in communication with the second gas channel through the third gas hole and the fourth gas hole.

Abstract: A key structure includes a keycap, a base plate and a supporting element. The supporting element includes a first frame and a second frame. The supporting element is connected with the keycap and the base plate. Consequently, the keycap is movable upwardly or downwardly relative to the base plate. When the first frame and a second frame are combined together, a first span and a second span are formed sequentially. The second span is smaller than the first frame.

Abstract: A key structure includes a keycap, a base plate, a first scissors-type connecting element, a second scissors-type connecting element and a reinforced connecting rod. The first and second scissors-type connecting elements are arranged between the keycap and the base plate. The first scissors-type connecting element includes a first inner frame and a first outer frame. The second scissors-type connecting element includes a second inner frame and a second outer frame. The keycap is movable upwardly or downwardly relative to the base plate along a specified path with the assistance of the first and second scissors-type connecting elements. The reinforced connecting rod includes a hollow rectangular main body. The first outer frame has a first extension structure. The second outer frame has a second extension structure. Moreover, two opposite sides of the hollow rectangular main body are respectively received within the first extension structure and the second extension structure.

Abstract: A key structure includes a keycap, a base plate, a first scissors-type connecting element, a second scissors-type connecting element and a reinforced connecting rod. The first and second scissors-type connecting elements are arranged between the keycap and the base plate. The first scissors-type connecting element includes a first inner frame and a first outer frame. The second scissors-type connecting element includes a second inner frame and a second outer frame. The keycap is movable upwardly or downwardly relative to the base plate along a specified path with the assistance of the first and second scissors-type connecting elements. The reinforced connecting rod includes a hollow rectangular main body. The first outer frame has a first extension structure. The second outer frame has a second extension structure. Moreover, two opposite sides of the hollow rectangular main body are respectively received within the first extension structure and the second extension structure.