Patent Application
20120048701
1. Field of Invention
The invention relates to keyboards and more particularly to an illuminated keyboard with improved characteristics.
2. Description of Related Art
Laptops are widely used throughout the world. Typically, a laptop is equipped with a scissor-switch keyboard. In detail, a plurality of scissor switches each is mounted between a key and a base plate. Scissor-switch keyboards are advantageous for being lightweight, low-profile, and easy operation. However, a user may operate such laptop in an illuminated environment since back light arrangement is not provided by the laptop. Thus, sometimes their uses are inconvenient.
A typical illuminated keyboard is characterized in that LEDs (light-emitting diodes) are attached to bottom of a PCB (printed circuit board). LEDs may emit light upward to illuminate the PCB and components thereon. However, no light guide means for directing a uniform illumination to the keys is provided. Thus, some keys proximate to the LEDs are sufficiently and other keys distal the LEDs are dim. This can cause inconvenience in use.
Another typical illuminated keyboard is characterized in that a film circuit board is provided on an aluminum plate. Under the aluminum plate there is a backlight layer. LEDs are provided on the backlight layer. Light emitted by the LEDs is directed upward through holes of the aluminum plate and circuit board onto bottom of keys. It is advantageous for being capable of effecting a uniform illumination to all keys. However, the combination of the circuit board, the aluminum plate, and the backlight layer can greatly increase thickness of the keyboard. This can compromise the low-profile feature of laptops. Thus, the need for improvement still exists.
It is therefore one object of the invention to provide an illuminated keyboard comprising a plurality of keys arranged in a matrix layout; a base plate; an LED circuit board disposed on the base plate and comprising a first circuitry and a plurality of LEDs electrically connected to the first circuitry to be powered therefrom; a spacer plate disposed on the LED circuit board, the spacer plate comprising a plurality of units each corresponding to the key thereabove, each unit including two first groove connectors, two second groove connectors, and at least one opening each for receiving the LED; an optically transmissive film circuit board for generating signals in response to a pressing of the key, the film circuit board disposed on the spacer plate and comprising a second circuitry, a plurality of switch contacts, and a plurality of holes each being in a one to one relationship to the first or second groove connector so that the first or second groove connector is adapted to pass through the hole; and a rubber plate formed of optically transmissive plastic and disposed on the film circuit board, the rubber plate comprising a plurality of resilient domes each disposed between the key and the switch contact, the dome having a recessed top for retaining the key, a conductive bottom stem disposed above the switch contact, and a plurality of through holes grouped as a plurality of groups, each group formed as four corners around the dome, the through holes being aligned with the holes and the first groove connectors or the second groove connectors so that the first or second groove connectors are adapted to pass through the holes.
The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings.
Referring to
A base plate 2 is waterproof. An LED circuit board 3 is mounted on the base plate 2 and comprises a first circuitry 31 electrically connected to a power source (not shown), and a plurality of LEDs 32 electrically connected to the first circuitry 31. Thus, power can be supplied to the LEDs 32 for illumination via the first circuitry 31. The power source can be the same as the one for supplying power to a film circuit board 5 or an independent one.
A plurality of keys 7 are arranged in a matrix layout and each is illuminated by at least one LED 32. A cup shaped reflector 33 is provided to contain the LED 32 therein (see
A spacer plate 4 is made of aluminum or plastic and is provided on the LED circuit board 3. The spacer plate 4 comprises a plurality of units each corresponding to a key 7 thereabove and including two snapping grooves 41 as one group, two slide guide grooves 42 as the other group, and two holes 43 formed between the groups. The number of the holes 43 corresponds to that of the LEDs 32. In short, each LED 32 is disposed in the hole 43.
The film circuit board 5 is optically transmissive and is provided on the spacer plate 4. The film circuit board 5 comprises a second circuitry 51 and a plurality of switch contacts 52 each is disposed below a key 7. The film circuit board 5 is capable of generating signals in response to a key press. A plurality of (four) holes 53 are provided in a one to one relationship to the snapping groove 41 or the slide guide groove 42 so that the snapping groove 41 or the slide guide groove 42 may pass through the hole 53.
A rubber plate 6 is formed of optically transmissive plastic and is provided on the film circuit board 5. The rubber plate 6 comprises a plurality of resilient domes 61 each disposed below a key 7 and on a switch contact 52, the dome 61 having a top receptacle (not numbered) and a conductive bottom stem 611 disposed above the switch contact 52, and a plurality of holes 62 grouped as a plurality of groups each group formed as four corners around the dome 61, the holes 62 being aligned with the holes 53 and the snapping grooves 41 or the slide guide grooves 42 so that the snapping grooves 41 or the slide guide grooves 42 may pass through the holes 62. A downward movement of the stem 611 can contact the switch contact 52 to close a circuit as typically known in a key pressing operation. Thus, its detailed description is omitted herein for the sake of brevity.
The keys 7 are arranged on the rubber plate 6 based on a default arrangement. The key 7 comprises a key cap 71 including on a bottom two pivot grooves 711, two slide guide grooves 712 with the pivot grooves 711 together arranged as four corners of a virtual quadrilateral, and a shaft 713 extending downward from the center to dispose in the receptacle of the dome 61; and a scissor shaped structure 72 disposed on the rubber plate 6 and including two first slide axles 721 at two corners of a first frame (not numbered), two second slide axles 722 at two corners of a second frame (not numbered) pivotal about the first frame, the second slide axles 722 being below the first slide axles 721, a first pivot shaft 723 at the opposite side of the second frame, a second pivot shaft 724 at the other side of the first frame parallel to and below the first pivot shaft 723, and a central circular hole 725. The first pivot shaft 723 is rotatably secured to the pivot grooves 711 and the first slide axles 721 are slidably secured to the slide guide grooves 712 respectively. The second slide axles 722 are slidably secured to the slide guide grooves 42 and the second pivot shaft 724 is rotatably secured to the snapping grooves 41 respectively.
In use, a user may press the key 7 to push down the shaft 713 which in turn presses the dome 61 with the scissor shaped structure 72 being elastically compressed. Thus, the stem 611 contacts the switch contact 52 to close a circuit (i.e., switch). As a result, the depressed key 7 is activated. Further, light emitted by the LEDs 32 which is powered by an independent power source is substantially uniformly directed upward toward the keys 7 through the film circuit board 5 and the rubber plate 6 when the keyboard 1 is turned on. Hence, the keys 7 are lit uniformly.
The illuminated keyboard 1 of the invention has the following advantages. It can be manufactured in low-profile. The LED circuit board 3 is provided under the film circuit board 5 in a spaced fashion. Hence, no contact between the LEDs 32 and the film circuit board 5 is made. This eliminates the need of drilling the LED circuit board 3 which may adversely affect the yield of the product. Further, any malfunctioned LEDs 32 can be replaced individually without having to replace the LED circuit board 3 and the film circuit board 5. This can greatly increase the production with decreased product defectiveness. Moreover, the LED circuit board 3 can be replaced individually when it is malfunctioned. This can be done without replacing the film circuit board 5. Hence, the production cost is greatly reduced and maintenance is made easier.
While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.
