A neuromuscular stimulation device is described having a plastic casing housing a printed circuit board bearing control electronics, with the casing including an external integral flexible portion which is capable of being flexed into the interior of the casing so as to cause an electrically insulative substrate on which is carried an electrically conductive pathway to be pushed into contact with the PCB in order to complete an electrical circuit. Such a switch is relatively inexpensive to produce, as it has few moving parts, can be formed in a usual manufacturing process, and is robust.

A neuromuscular stimulation device is described having a plastic casing housing a printed circuit board bearing control electronics, with the casing including an external integral flexible portion which is capable of being flexed into the interior of the casing so as to cause an electrically insulative substrate on which is carried an electrically conductive pathway to be pushed into contact with the PCB in order to complete an electrical circuit. Such a switch is relatively inexpensive to produce, as it has few moving parts, can be formed in a usual manufacturing process, and is robust.

A key structure having a pressing area is provided. The key structure includes a first membrane and a second membrane. A first conductive layer and a first insulation layer are sequentially disposed on a surface of the first membrane. The first insulation layer has a first opening in the pressing area, so that a part of the first conductive layer is exposed from the first opening. The second membrane is disposed opposite to the first membrane. A second conductive layer and a second insulation layer are sequentially disposed on a surface of the second membrane facing the first membrane. The second insulation layer has a second opening, which is formed corresponding to the first opening, in the pressing area, so that a part of the second conductive layer is exposed from the second opening to face the first conductive layer in the first opening.

A key structure includes a movable element, an elastic element, a light-emitting element and a pressure sensing element. The pressure sensing element is arranged between the elastic element and the light-emitting element. The elastic element is disposed on the movable element. The light-emitting element emits a light beam. The light beam is transmitted through the pressure sensing element and projected to the movable element to illuminate the key structure. While the key structure is depressed, the elastic element is pushed by the movable element. The pressure sensing element is pushed by the elastic element according to different magnitudes of the depressing force. Consequently, the key structure generates different pressure sensing signals.

A key structure having a pressing area is provided. The key structure includes a first membrane and a second membrane. A first conductive layer and a first insulation layer are sequentially disposed on a surface of the first membrane. The first insulation layer has a first opening in the pressing area, so that a part of the first conductive layer is exposed from the first opening. The second membrane is disposed opposite to the first membrane. A second conductive layer and a second insulation layer are sequentially disposed on a surface of the second membrane facing the first membrane. The second insulation layer has a second opening, which is formed corresponding to the first opening, in the pressing area, so that a part of the second conductive layer is exposed from the second opening to face the first conductive layer in the first opening.

A key structure includes a movable element, an elastic element, a light-emitting element and a pressure sensing element. The pressure sensing element is arranged between the elastic element and the light-emitting element. The elastic element is disposed on the movable element. The light-emitting element emits a light beam. The light beam is transmitted through the pressure sensing element and projected to the movable element to illuminate the key structure. While the key structure is depressed, the elastic element is pushed by the movable element. The pressure sensing element is pushed by the elastic element according to different magnitudes of the depressing force. Consequently, the key structure generates different pressure sensing signals.