Abstract:
A lighting source, such as a light emitting diode (LED), is incorporated into the shaft of the pointing device. There is a light shield over the exposed top of the pointing device preferably, backed with a conically shaped reflecting surface to direct the light outwardly and horizontally across the keyboard. The light is activated in a laptop by opening the cover to raise the pointing device to its normal operating position. The lighting function may be disabled when the pointer is raised if there is sufficient ambient lighting.

Description:
FIELD OF THE INVENTION 
     The present invention relates to keyboard lighting and more particularly, to incorporating a lighting device into the keyboard of a portable computer. 
     BACKGROUND OF THE INVENTION 
     Either back or front lighting can be used to illuminate a full travel keyboard in a dimly lit ambient environment. Back lighting requires that an incandescent light bulb or a light-emitting diode (LED) light source be placed inside the keyboard. When power is applied, the light source illuminates by transmission from the rear the legends on the key caps of the keyboard. Front lighting requires that a light source, typically with an adjustable brightness incandescent light bulb, be place above the keyboard. When power is applied, light from the lamp illuminates by reflection off the legends on the key caps. 
     Each keyboard-lighting technique has advantages and disadvantages. Back lighting has the advantage in that it is integrated with the keyboard to eliminate annoying vision obstructions onto and behind the keyboard. In back lighting, each key is illuminated to avoid finger shadows on the key caps and provide good key cap legend readability. Also, the brightness of the keyboard can be easily adjusted to avoid display reflections and suit different lighting conditions and user preferences. 
     However, back lighting has disadvantages in that the keyboard itself is usually thicker to accommodate light source and other support electronics. Back lit keyboards are also quite expensive due to low volume and unusual, customized electronics. They suffer from low reliability due to electronic complexity and require a relatively large amount of power. 
     Front lighting has an advantage in that it is much lower in cost to implement. However, prior art front lighting also has disadvantages. Among them being that the lamp usually obstructs the user&#39;s view of the computer screen and possibly access to keys on the keyboard because the lamp is usually positioned above the keyboard in the user&#39;s line of sight. 
     For the above reasons and other reasons, prior art back lighting or front lighting techniques have provided optimal keyboard lighting technique. 
     Therefore, it is an object of the present invention to provide a new electroluminescent keyboard light. 
     It is another object of the present invention to provide a keyboard level light source. 
     Further objects of the invention is to provide a light source for a computer keyboard that is inexpensive, efficient and easy to operate. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In accordance with the present invention, a lighting source, such as a light emitting diode (LED), is incorporated into the shaft of a pointing device positioned among the keys of a keyboard. A light shield or cap is attached to the top of the pointing device so that the light from the light source extends outwardly and horizontally across the keyboard to provide light to the keyboard without interfering with the viewing of the computer screen. Reflecting surfaces can be incorporated into the underside of the cap and at the base of the light source to intensify the light provided to the keyboard. The light is activated when the pointing device is raised to its normal operating position. When ambient lighting is sufficient, the lighting function may be disables when the pointed is raised. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention and its objects, features and advantages can best be understood by reading the following description of the preferred embodiments while referring to the accompanying figures of which: 
     FIG. 1 is a perspective view of a portable PC with its cover; 
     FIG. 2 is a diagram of a pointer in accordance with the present invention; 
     FIGS. 3 and 4 are diagrams of a mechanism for raising and lowering the pointer in response to opening and closing of a laptop cover; 
     FIGS. 5 and 6 are sectional views of a carrier for the pointer responsive to the mechanism for raising or lowering the pointer; and 
     FIG. 7 is a side view of a cam device to activate the mechanism of FIGS.  3  and  4 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a laptop computer  10  comprises a lower case  14 , a cover  16 , an electronic circuit  18  in the lower case  14  and a display  20  in the cover. The cover  16  is mechanically and electrically attached to the base  14  at pivot joints  24  and  24 A, so that the cover  16  can pivot between a closed position (not shown) through the partially opened position shown in FIG. 2, to a fully opened position (not shown). A liquid crystal display (LCD) screen  20 , is mechanically connected to the inner side of the cover  16  and is electrically connected to the electronic circuit  18 . The electronic circuit  18  is stored within the lower case  14  or within the cover  16 , or partially stored within both of them. The electronic circuit  18  includes an electronic processor and electronic memory. 
     The pointing device  30  shown in FIG. 1 is electrically connected to the electronic circuit  18  to move a cursor across the LCD screen  20 . As shown in FIG. 2, the pointing device  30  of the present invention includes a cylindrical shaft  31  with a transparent portion  32  and an opaque portion  33 . Set within the cyclindral portion is an LED  34 . Electrical connections  35  and  36  in the opaque portion  33  connect the LED  34  to electrical contacts  37  and  38  on the underside of a base plate  104  carrying the shaft  31 . The contacts  37  and  38  make electrical connection to electrical contacts embedded in a canted pallet  112  on which the base plate  104  rides as the cover is opened and closed. As shown, the pointing device is in its operative position and electrically activated by source  39  through switch  44 . The switch  44  is provided to deactivate the LCD  34  when there is sufficient ambient light and the LCD light is obtrusive. The switch can be a mechanical switch  45  on the body of the laptop or can be activated by cursor or key selection. 
     The top of the shaft  31  is covered by a roughened cap  40  which not only functions as a contact surface for operating the pointing device, but as a light shield preventing light from exiting the shaft through its top and interfering with viewing of the screen  20  by a user. In this embodiment, a conically shaped convex lens  41  to direct the light out laterally over the surface of the keys  42  of the laptop keyboard. The lens  41  may be formed by providing a silvered surface on a cavity  43  in a potting compound encapsulating the LED  34 . 
     As pointed out above, the pointing device  30  is shown in FIG. 2 in its raised and operative position so that light is provided to the keyboard  28 . In keyboards where height of the pointer is not a problem, the operative or raised position of the pointer can be permanent. However in laptops and other portable devices that have tops that contain viewing screens, the height of the pointing device would have to be accommodated by the thickness of the laptops case otherwise, the top of the pointing device will press upon the laptop screen  20  possibly damaging the screen and/or the pointing device. An elevating and lowering mechanism for a pointing device of a portable PC is shown in U.S. Pat. No. 5,708,562, the contents of which patent are hereby incorporated by reference. This mechanism automatically elevates and lowers the operating end for a pointing device on concert with the relative position of the cover  16  of the case. 
     Referring to FIGS. 3 and 4, a first drive arm  158  in this embodiment has an end portion  164 , in which is formed a guide slot  160 , and a central connection area  168 , in which is formed a socket area  170 . The central connection area  168  is held to the lower case  14  by a pivot pin  156  around which it pivots. The guide slot  160  is formed in an appropriate shape so that in conjunction with a clearance slot  146  it can provide a desired operation of an arm  110  in the case. The base portion  104 , which fixed in place the point device  30 , is connected at the right side to the keyboard  26  by means of the hinges  106  and  108 , as can best be seen in FIGS. 5 and 6. As shown in FIGS. 5 and 6, an opening is contained in the keyboard  26  to permit the operated end of the pointing device  30  to extend upward. Referring back to FIGS. 3 and 4, the elevating and lowering mechanism in this embodiment includes a second drive arm  72 . The second drive arm  72  is installed on the system  12  and is held by a pivot  74  so that it freely pivots. The second drive arm  72  has a first end portion  76  and a second end portion  78 . At the distal end of the first end portion  76  is formed a ball section  80  that is inserted into the socket  70  in the first drive arm  158  so as to set it in the operating state. In the second end portion  78  is formed a cam slot  82  with a cam pin  84  inserted therein. The cam pin  84  reduces the influence of friction and provides a smoother operation in the slot  82 . 
     Referring to FIG. 7, the dam pin  84  is extended downward from a cam slider  86 . The cam slider  86  is so installed in the system  12 , parallel to the rotary shaft of the cover  16 , that it is slidable. The cam slider  86  is biased to the left by a tension spring  88 . On the cam slider  86  is a rider section  90  that contacts a cam surface  92  of the left pivot joint  24 A by which the cover  16  is attached to the system  12 . When the cover  16  is to be pivoted and thus closed from the opened position, the pivot joint  24 A rotates as is indicated by the arrow D. Then, the cam surface  92  is driven against the rider section  90 , the cam slider  86  is shifted to the right, as is indicated by the arrow B, and the tension spring  88  is stretched. When the cover  16  is to be pivoted from the closed position to the open position, the pivot joint  24 A rotates the opposite direction. The tension spring  88  pulls the cam slider  86  in the direction that is the opposite of the direction B as the rider section  90  moves along the cam surface  92  to place the keyboard in the operating position. The force that is exerted to arrange the keyboard is only the force that is generated by the tension spring  88 . This structure protects the internal mechanism when the extension of a pallet is interrupted in a third embodiment, which will be described later. This arrangement is therefore preferable for driving the cam slider  86  directly into the cover at the extended operating position. 
     A shifting mechanism, and the movement of the pallet from the storage position to the operating position will now be described. In FIG. 3 is shown an elevating and a lowering mechanism at the storage position. In this embodiment, the first drive arm  158  is so held by the pivot pin  156  that it can be pivoted. On the first drive arm  158  is the end portion  164  in which is formed the guide slot  160 , and the central connection area  168  in which is formed the socket area  170 . The central connection area  168  is so fitted around the pivot pin  156  that it can be freely pivoted. 
     As is described above, in FIG. 3 is shown the storage positions of the components when the cover  16  is closed. In this condition, the cam slider  86  and the cam pin  84  are positioned completely to the right by the cam surface  92  of the pivot joint  24 A, which acts on the rider section. In the illustration in FIG. 4, which is a schematic diagram, as is in FIG. 3, are depicted components when the cover  16  is pivoted and opened. As is apparent from the comparison of the diagrams in FIGS. 3 and 4, the cam pin  84  is shifted to the left. Thus, the second drive arm  72  pivots as in indicated by the arrow E because the center section of the cam slot  82  is formed with an angle. Since the pivot  74  is fixed to the base  14 , the first end portion  76  of the second drive arm  72  rotates the first drive arm  158  in the direction F. Due to the interaction with the guide slot  160  for the first drive arm  158 , the arm  110  is driven by the first drive arm  158  in the horizontal direction indicated by B. The first drive arm  158  pivots around the pivot pin  156 , while the ball section  80  of the second drive arm  72  pivots within the socket area  70  in the first drive arm  58 . 
     As is shown in FIGS. 5 and 6, as the arm  110  is shifted in the horizontal direction A, the base portion  104  is driven upward by a second shelf portion  116  via a sloped portion  112 , and the operation section of the pointing device  30  is lifted. It is only in this raised position that an electrical connection is made to the source  39 . Thus, the pointer is darkened when the pointer  30  is retracted. It is preferable that a positioner, such as a leaf spring, or an indentation that corresponds in shape to the base portion  104 , be provided for the second shaft portion  116  in order to prevent the pointing device from wobbling while it is being manipulated. It is desirable that the pointer  30  have a mechanical failure load that is greater than approximately 3.624 Kg (8 pounds). Although, in the first embodiment the base portion  104  is connected to the keyboard  26  by means of the hinges  106  and  108 , a flexible member, such as a compression coil spring or a leaf spring, can be employed to connect the base portion  104  to the keyboard  26 . 
     The shifting of the pallet from the storage position to the operating position has been explained. To move the pallet from the operating position to the storage position, a user merely closes the cover. The elevating and lowering mechanism then automatically moves the arm  110  inversely. As the arm  110  is shifted in the horizontal direction B, the base portion  104  is moved to the first shaft portion  114  across the sloped portion  112 , and as a result, the operating section of the pointing device  30  is lowered. 
     While one illustrated example of the present invention has been explained, a number of modifications can be made without departing from the spirit and scope of the invention. For instance, the described mechanisms for raising and lowering the pointed can be replaced with other mechanisms of various shapes and types, such as electrically activated mechanisms. Further, the elevating and lowering mechanism that is related to the present invention can be also incorporated in keyboards of the other types of computers. In addition, components or materials of arbitrary sizes, shapes and types can be employed. Therefore, it should be understood that the invention is not limited to the disclosed embodiments but should be construed in accordance with the spirit and scope of the accompanying claims.