An example circuit includes a plurality of light emitters connected in parallel between a first node and a second node. The circuit also includes a plurality of capacitors, with each capacitor corresponding to one of the light emitters, and a plurality of discharge-control switches, with each discharge-control switches corresponding to one of the capacitors. The circuit further includes a pulse-control switch connected to the plurality of light emitters. During a first period, the pulse-control switch restricts current flow, and each of the plurality of capacitors is charged via the first node. During a second period, one or more of the plurality of discharge-control switches allows current flow that discharges one or more corresponding capacitors. During a third period, the pulse-control switch allows current flow that discharges one or more undischarged capacitors of the plurality of capacitors through one or more corresponding light emitters.

Problem To be capable of specifying an operation of a knob. Solution A switch 1 includes an operation detecting portion 7 which detects an operation of the knob 5. The operation detecting portion 7 includes a movable member 6 which displaces in association with the operation of the knob 5, a through hole 62a which penetrates through a light shielding portion 62 of the movable member 6 in a thickness direction thereof, one optical source 15 which is provided on one side of the movable member 6 in the thickness direction, a light guiding path 9A which is provided on the other side of the movable member 6 in the thickness direction, and two light receiving elements 10A, 10A which are attached to the light guiding path 9A. The light guiding path 9A is arranged in a position of being capable of receiving light emitted from the optical source 15 through the through hole 62a when the movable member 6 is arranged in a predetermined position by the operation of the knob 5.

Problem To be capable of specifying an operation of a knob. Solution A switch 1 includes an operation detecting portion 7 which detects an operation of the knob 5. The operation detecting portion 7 includes a movable member 6 which displaces in association with the operation of the knob 5, a through hole 62a which penetrates through a light shielding portion 62 of the movable member 6 in a thickness direction thereof, one optical source 15 which is provided on one side of the movable member 6 in the thickness direction, a light guiding path 9A which is provided on the other side of the movable member 6 in the thickness direction, and two light receiving elements 10A, 10A which are attached to the light guiding path 9A. The light guiding path 9A is arranged in a position of being capable of receiving light emitted from the optical source 15 through the through hole 62a when the movable member 6 is arranged in a predetermined position by the operation of the knob 5.

A key of an optical mechanical keyboard, having a base plate, a circuit board, an optical switch, a rotating member, a key cap, a pressing cylinder, a primary spring, and a secondary spring. A ring-shaped fastening member is provided on the base plate, and a side wall of the ring-shaped fastening member is provided with two opposing first light-admitting slots, and a keystroke impact slot is respectively provided at two sides of and between the opposing first light-admitting slots. The key has a simple structure and is lightweight and slim, and enables generation of a clear sound upon striking a key.

A key of an optical mechanical keyboard, having a base plate, a circuit board, an optical switch, a rotating member, a key cap, a pressing cylinder, a primary spring, and a secondary spring. A ring-shaped fastening member is provided on the base plate, and a side wall of the ring-shaped fastening member is provided with two opposing first light-admitting slots, and a keystroke impact slot is respectively provided at two sides of and between the opposing first light-admitting slots. The key has a simple structure and is lightweight and slim, and enables generation of a clear sound upon striking a key.

A control panel for controlling a device comprises a scanning device being a plane surface scanner configured for scanning instantaneously an image of a surface of interest. It also comprises a front panel with a front side surface facing the user and a back side surface facing the scanning device and thus being scanable and at least one controller element mounted in the front panel and having contrast markings at the back side facing the scanner device with respect to a color of other portions of the back side of the front panel so that a state of the at least one controller is recognizable from an optical image of the back side of the front panel.

A control panel for controlling a device comprises a scanning device being a plane surface scanner configured for scanning instantaneously an image of a surface of interest. It also comprises a front panel with a front side surface facing the user and a back side surface facing the scanning device and thus being scanable and at least one controller element mounted in the front panel and having contrast markings at the back side facing the scanner device with respect to a color of other portions of the back side of the front panel so that a state of the at least one controller is recognizable from an optical image of the back side of the front panel.

A keyboard device includes plural key structures, an electronic paper display element and an illumination module. The electronic paper display element is disposed under the plural key structures. The plural key symbols corresponding to the plural key structures are displayed on the electronic paper display element. The illumination module is disposed over the electronic paper display element to provide a light beam to the electronic paper display element. Consequently, the plural key symbols are illuminated.

A keyboard device includes plural key structures, an electronic paper display element and an illumination module. The electronic paper display element is disposed under the plural key structures. The plural key symbols corresponding to the plural key structures are displayed on the electronic paper display element. The illumination module is disposed over the electronic paper display element to provide a light beam to the electronic paper display element. Consequently, the plural key symbols are illuminated.

A key module includes a bottom plate, a circuit layer, a key cap, a supporting structure, a touch member, and a flexible circuit board. The bottom plate has a first surface and a second surface opposite to each other. The circuit layer is disposed on the first surface and has a first opening. The key cap is disposed above the circuit layer and covers the first opening. The supporting structure is disposed between the bottom plate and the key cap. The touch member is disposed at the key cap. The flexible circuit board is electrically connected to the touch member and passes through the first opening to extend next to the second surface of the bottom plate. When the key cap moves downward relative to the bottom plate, a portion of the flexible circuit board located between the key cap and the bottom plate is bent.