Abstract:
A keyboard lighting device is disclosed. In a preferred embodiment, a moving member may be placed in an operating position protruding from the keyboard, or in a retracted position. In the operating position, light is redirected from a light source to the keyboard so that use of the keyboard in dark environments is facilitated. Preferably, when the moving member is in its retracted position, the keyboard light appears to be a key on the keyboard.

Description:
FIELD OF THE INVENTION  
       [0001]     present invention relates to portable electronic devices, and more specifically to supplemental keyboard lighting for a portable electronic device.  
       BACKGROUND  
       [0002]     A laptop or “notebook” portable computer serves as an example of a portable electronic device.  FIG. 1  shows a simplified perspective view of a typical laptop portable computer  100 . Computer  100  comprises a base portion  101 , further comprising a keyboard  103  and other input devices, and a display portion  102 , comprising a display for communicating information to a user of computer  100 . Keyboard  103  further comprises a row  104  of special function keys, in addition to the alphabetic and numeric keys typically found on a keyboard.  
         [0003]     A portable device such as computer  100  is intended to be used in many different environments. For example, computer  100  may be used out of doors, in a car, on an airplane, or in nearly anywhere else the user desires. Computer  100  may operate for a limited time on battery power when no external supply of power is available. Not all of these usage locations are ideal working environments. For example, during a long airline flight, cabin lighting is often extinguished so that the passengers can sleep. A passenger wishing to continue working at his seat after “lights out” may have difficulty seeing keyboard  103 .  
         [0004]     Various devices have been proposed for illuminating a portable device keyboard. Many require additional equipment to be carried with the portable device. Kim (U.S. Pat. No. 6,336,727) describes a lighting device integrated into a cursor control device that resides near the center of a computer keyboard. However, not all computers or other portable devices use the kind of cursor control device described by Kim, and such a device may not extend high enough above the keyboard to provide sufficient light. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  shows a simplified perspective view of a laptop portable computer.  
         [0006]      FIG. 2  shows a simplified perspective view of a laptop portable computer in accordance with an example embodiment of the invention.  
         [0007]      FIG. 3  shows a cutaway perspective view of a keyboard light, in accordance with an example embodiment of the invention, in its operating position.  
         [0008]      FIG. 4  shows the example computer of  FIG. 2  with a keyboard light, in accordance with an example embodiment of the invention, in a retracted position. 
     
    
     DETAILED DESCRIPTION  
       [0009]      FIG. 2  shows a simplified perspective view of a laptop portable computer  200  in accordance with an example embodiment of the invention. Example computer  200  comprises a base portion  201 , further comprising a keyboard  203 . Keyboard  203  further comprises a row  204  of special function keys. Because there are more available key positions than are needed to provide special functions, one of the key positions is usurped by a keyboard light  205  in accordance with an example embodiment of the invention. While a key position is a convenient place for keyboard light  205 , keyboard light  205  might also be placed in any otherwise-blank part of base portion  201 , such as area  206 . Keyboard light  205  is preferably placed approximately midway along the rows of keys of keyboard  203 , in or near the “top” row of keys (the row furthest from the user, row  204  in the example embodiment), and such that it does not interfere when the computer user types on keyboard  203 . In  FIG. 2 , keyboard light  205  is shown in its operating position.  
         [0010]      FIG. 3  shows a cutaway perspective view of example keyboard light  205  in its operating position. Keyboard light  205  comprises a moving member  306 , which includes the moving parts of keyboard light  205 . Keyboard light  205  further comprises a light source, such as light emitting diode (LED)  301 . While the example embodiment of  FIG. 3  uses an LED as its light source, another kind of light source may be used, such as an incandescent lamp or another kind of light source. The light source is powered by any of a number of means well known in the art. LED  301  emits light, represented by light rays  302 . The light transmits through light pipe  303 , which is shaped to disperse the light effectively over keyboard  203 . Light pipe  303  may be made of a clear plastic material such as polycarbonate or acrylic. In an alternative embodiment, a light source such as LED  301  is mounted to a feature such as a circuit board inside computer  200  and does not move with the key-shaped portion of keyboard light  205 . Keyboard light  205  may comprise a second light pipe that transfers light from the fixed light source to light pipe  303 , or a single light pipe may transfer light from the fixed light source to keyboard  203 . One of skill in the art will recognize that light-transfer mechanisms other than a light pipe may be used. For example, keyboard light  205  may redirect light from a light source such as LED  301  using mirrors, lenses, diffuse reflective surfaces, prisms, light pipes, or other optical components, or any of these in combination.  
         [0011]     A designer of skill in the art may choose the number, orientations and surface treatments of the various surfaces of keyboard light  205  so as to work effectively to achieve a design goal using the light source chosen in a particular embodiment. For example, the designer may strive to distribute the light from the chosen light source as evenly as possible over keyboard  203 , or may strive to deliver the largest possible portion of the light from the light source to keyboard  203 . Other design goals may be envisioned.  
         [0012]     Preferably, keyboard light  205  is rotatable about its vertical axis  305 , so that light may be directed preferentially to particular parts of keyboard  203 .  
         [0013]     During times when supplemental illumination is not needed or desired, moving member  306  may be retracted into base portion  201 .  FIG. 4  shows example computer  200  with example moving member  306  in a retracted position. In the example embodiment of  FIG. 4 , when moving member  306  is retracted, keyboard light  205  harmonizes visually with the keys in row  204  of special function keys. That is, it appears to be a key on keyboard  203 .  
         [0014]     The retraction of keyboard light  205  and its extension to its operating position are preferably performed using a “push-push” mechanism. A push-push mechanism allows alternately latching of a surface in a retracted and an extended position. Each transition between the retracted position and the extended position is accomplished by pushing on the mechanism. That is, the push-push mechanism alternately places moving member  306  in its operating position and its retracted position. In example computer  200 , the user presses on the upper surface  304  (shown in  FIG. 3 ) of keyboard light  205  to retract moving member  306  from its operating position, and also presses on upper surface  304  to raise moving member  306  to its operating position from its retracted position.  
         [0015]     In a preferred embodiment, keyboard light  205  comprises an illuminated pushbutton switch, which further comprises a push-push mechanism, so that LED  301  is illuminated automatically when moving member  306  is in its operating position and is shut off automatically when moving member  306  is in its retracted position. Alternatively, control of LED  301  is independent of the position of moving member  306 . For example, LED  301  may be controlled by a separate switch actuated by the user of computer  200 , or may be controlled through software installed in computer  200 .  
         [0016]     Push-push mechanisms and illuminated pushbutton switches are well-known in the mechanical arts and need not be described in detail here. See, for example, U.S. Pat. No. 3,651,700 to Bailey, which describes an example push-push mechanism. U.S. Pat. No. 3,969,609 to Wanner et al. describes an example illuminated push button switch that may be illuminated in response to its selected position, or may be illuminated by a control independent of the switch position. Illuminated pushbutton switches are available from a variety of manufacturers, including NKK Switches of Scottsdale, Ariz., USA and ITT Industries, Cannon of Newton, Mass., USA.  
         [0017]     While a laptop portable computer has thus far been used as an example portable electronic device in which the invention may be embodied, the invention may be embodied in other portable electronic devices as well, for example a personal digital assistant (PDA). A PDA is typically a handheld device that comprises a display screen and a keyboard. Software and hardware comprised in a PDA may enable the device to act as a wireless telephone, an internet access device, or to perform computer-like functions for the convenience of the user. For example, a PDA may allow the user to access electronic mail, store and play digital sound files, store and display digital photographs, to do word processing, or other functions.