Abstract:
Methods are provided for adapting existing manufacturing processes for non-illuminated data-entry devices and mouses to the manufacture of illuminated data-entry devices. Luminescent sheets of one or more colors underlying optically transmissive device components provide illumination of the components visual to a user of the device. The optically transmissive components may be doped with phosphors or tinted to provide components that emit light of different colors. The intensity of illumination of the luminescent sheet may be controlled by the user and may vary in response to the background light of the environment.

Description:
[0001]    This application is a divisional application and claims priority from co-pending U.S. patent application Ser. No. 09/755,775, filed on Jan. 4, 2001, which is a divisional application of U.S. patent application Ser. No. 09/139,927, filed Aug. 26, 1998 (now U.S. Pat. No. 6,199,996), which are incorporated herein by reference. 
     
    
     
       TECHNICAL FIELD OF THE INVENTION  
         [0002]    The present invention relates to illumination of keyboards, keypads, and other data entry devices.  
         BACKGROUND OF THE INVENTION  
         [0003]    Keyboards, keypads, mouses, and other data entry devices (hereinafter referred to generally as keyboards) are used in a variety of applications for entry of alphanumeric and other types of data into a machine such as a calculator or computer. Keyboards have been developed that are light weight, low in cost, and relatively easy to manufacture. However, difficulty has been encountered in the development of illuminated keyboards that are light weight, low in cost and easy to manufacture. For example, methods have been developed which require placement of a light source below and in proximity of each key of the keyboard, and each of these light sources must be connected to a power supply, rendering the manufacture of such a keyboard difficult and expensive. Another method for illuminating a keyboard requires a single light source that provides light to each key by means of optical light paths. The optical light paths are difficult to construct in order to illuminate the keys uniformly and efficiently. These methods have the disadvantage of requiring considerable power for illumination, an important consideration for laptop computers and calculators operating under battery power. Moreover, all of these methods are unsuitable for many of the new keyboards that have been developed which are not flat, such as ergonomic keyboards that arc upward and outward from a horizontal surface. More generally, none of the methods of the prior art are readily adaptable to existing keyboard manufacturing processes. Thus, the manufacturing process for manufacturing ordinary non-illuminated keyboards cannot readily and easily be adapted to the manufacture of illuminated keyboards.  
         SUMMARY OF THE INVENTION  
         [0004]    An object of the present invention is to provide methods for manufacture of illuminated keyboards that can easily be adapted and incorporated into the manufacture processes that exist for non-illuminated keyboards.  
           [0005]    Another object of the present invention is to provide methods for manufacture of illuminated keyboards that may be applied to keyboards of any shape, including ergonomic keyboards.  
           [0006]    Another object of the present invention is to provide uniform illumination of the keys in a manner that does not require implementation of complex optical pathways or separate light sources for each key, and further provides illumination that consumes very low power.  
           [0007]    Yet another object of the present invention is to provide illumination that possesses controllable visual functionality as well as aesthetic attributes.  
           [0008]    According to one aspect of the present invention a flexible, thin, low power, inexpensive, luminescent sheet is adhered to the surface of the key board well plate of a keyboard. The key board well plate is manufactured in any manner and shape as required by the manufacturing process typically used and as required by the shape of the keyboard to be produced. The luminescent sheet may be adhered to the upper surface of the keyboard well plate. Alternatively, the luminescent sheet may be placed between the keyboard well plate and the circuit board of the keyboard. In this configuration the keyboard well plate is made from any optically transmissive material possessing sufficient rigidity to function as a key board well plate. Such materials, such as plexi-glass and other moldable plastics are well known in the art. The keys are also manufactured as required by the manufacturing process ordinarily used, except that the keys are made from an optically transmissive material, and may further contain phosphorescent material that glows residually during and after illumination. The luminescent sheet may be easily connected to a battery or any available power source, including the source that provides power to the keyboard itself. Further, the luminescent sheet may be connected to a device such as a rheostat to allow the user to vary the intensity of illumination. Also, a photo cell may be connected to the source of power of the luminescent sheet to cause the intensity of light from the sheet to automatically vary in response to the darkness of the environment in which the keyboard is used.  
           [0009]    According to the present invention, luminescent sheets of different colors can be placed under different sections of keys to improve visual differentiation of key groups. Also, the optically transmissive keys can be tinted so that the same luminescent sheets will cause keys tinted by different colors to appear in different colors. Similarly, the top plate of the keyboard which is normally opaque can also be manufactured from an optically transmissive material so that the entire upper surface of the keyboard will be illuminated. The top plate may be tinted to provide visual contrast. Also, one luminescent sheet of one color can be applied to illuminate the top plate with a color that is different from the color of the luminescent sheet that illuminates the keys. All of these features may be combined to provide an illuminated keyboard that possesses controllable visual functionality and aesthetic attributes. Further, the methods of the present invention disclosed herein can be implemented by persons of ordinary skill in the art to convert existing keyboards into illuminated keyboards.  
           [0010]    These and other features, aspects and advantages of the present invention will become apparent and better understood with reference to the following written description, attached drawings, and appended claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    For a more complete understanding of the present invention, and the advantages thereof, the following description is made with reference to the accompanying drawings, in which:  
         [0012]    [0012]FIG. 1 illustrates a construction of a typical keyboard.  
         [0013]    [0013]FIG. 2 illustrates placement of a luminescent sheet below a well plate.  
         [0014]    [0014]FIGS. 3 a ,  3   b  and  3   c  illustrate construction and electrical connection of a typical luminescent sheet.  
         [0015]    [0015]FIG. 4 illustrates an embodiment for illumination of a top plate.  
         [0016]    [0016]FIG. 5 illustrates placement of a luminescent sheet above a well plate. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    A functional diagram of the construction of a typical keyboard is shown in FIG. 1. Typically, a keyboard  5  is comprised of keypads  10 , keystems  11 , a keyboard top plate  20 , a keyboard well plate  30 , a circuit board  40  with key spring switches  13  and a key board bottom plate  50 . Typically all of these components are manufactured of opaque materials. Keystems  11  are inserted through holes  12  in keyboard well plate  30 . Holes  12  in keyboard well plate  30  are aligned with key spring switches  13  of circuit board  40 . Circuit board  40  is secured to key board bottom plate  50 . Key board top plate  20  fits over or otherwise attaches to key board bottom plate  50 , and thereby provides enclosure for the keyboard. Typically, keys are grouped in a keyboard according to function. For example, on a typical keyboard for typing words and data into a word processor, a set of alphabet keys, number keys, and other certain symbol keys are grouped together in a traditional typewriter key layout, herein referred to as the typewriter keys. Another separately grouped set of keys are the arrow keys which allow control of a cursor displayed on a video monitor. Function keys are separately grouped in a single line across the upper portion of the key board. Etc. These separately grouped sets of keys will be referred to as key groups. Top plate  20  is designed so that when placed in position, the keypads  10  extend through top plate  20  while the areas between key groups are covered by surface  21  of top plate  20 .  
         [0018]    A preferred embodiment of the present invention is illustrated in FIG. 2. A flexible luminescent sheet  100  is adhered to the lower surface  32  of key board well plate  30  that faces the surface of circuit board  40 . Any suitable substance known in the art that is optically transmissive may be used to adhere luminescent sheet  100  to lower surface  32 . Alternatively, flexible luminescent sheet  100  may be placed between keyboard well plate  30  and circuit board  40  without the use of an adhering substance, if luminescent sheet  100  will be sufficiently compressed between keyboard well plate  30  and circuit board  40  to remain in place. Holes  112  are made in flexible luminescent sheet  100  to align with holes  12  in keyboard well plate  30 .  
         [0019]    Luminescent sheet  100  is comprised of a commercially available electroluminescent (E-L) lamp. E-L lamps are solid state devices constructed of thin phosphor-coated plastic sheets with conductive surfaces. When a power source is applied to the conductive surfaces the phosphors illuminate and light is emitted from the entire surface. E-L lamps are thin, flexible and can be twisted, bent or formed into any shape. These lamps draw very little power and produce very little heat. A typical construction of luminescent sheet  100  is illustrated in FIG. 3A. Each conductive surface, metallized polyester film  131  and rear electrode  132 , is connected at an edge of sheet  100  by electric leads  105 . The upper conductive surface, metallized polyester film  131 , is an optically transmissive conductor. When leads  105  are connected to a power source  110 , the entire sheet illuminates with an intensity that is substantially uniform across the entire surface of sheet  100 . Luminescent sheets are commercially available in a variety of colors such as white, yellow, blue and green. They may be cut to order by the manufacturer, who will provide electrical tabs connected to the conductive surfaces for connection to an electrical power source. For example, flexible luminescent sheets may be obtained from SEG Corporation. SEG may be contacted through their Internet address: www.flashseg.com.  
         [0020]    Flexible luminescent sheet  100  is connected through leads  105  to any convenient power source  110 , which may be a battery or the power source of keyboard  5 . The intensity of light from luminescent sheet  100  can be varied using an intensity control device  85  such as a rheostat in series with power source  110 , as illustrated in FIG. 3B. In addition, or in the alternative as shown in FIG. 3B, intensity may be controlled by providing a photosensitive device  90 , such as a photo-cell, and associated circuitry to control the intensity of luminescent sheet  100  in response to the intensity of light in the environment in which keyboard  5  is used. A variety of methods, devices, and circuitry for controlling the intensity of luminescent sheet  100  will readily be recognized by persons of ordinary skill in the art.  
         [0021]    In this embodiment, keyboard well plate  30  is manufactured from an optically transmissive material. Any optically transmissive material that is sufficiently rigid to achieve the ordinary purposes of a keyboard well plate will suffice. Even a partially opaque optically transmissive material may be used as long as light of sufficient intensity is transmitted through keyboard well plate  30  to provide illumination visual to the user. Examples of materials that can be used for this purpose are plexiglass and other optically transmissive plastics. Other suitable materials will be known to persons of ordinary skill in the art. Similarly, keypads  10  and key stems  11  will be manufactured from an optically transmissive material, that is, materials that are at most only partially opaque and transmit sufficient light intensity to render the keys visual to the user. In addition, keypads  10  may comprise phosphors that will illuminate in response to the light received from luminescent sheet  100 . Thus, in this embodiment, luminescent sheet  100  transmits light through keyboard well plate  30  and through keypads  10  to provide visual illumination of keyboard  5 .  
         [0022]    It may be desirable in some applications to provide a keyboard in which different keys, key groups and keyboard areas appear in different colors of illumination. A variety of methods can be implemented to achieve this according to the methods of the present invention. One method is to provide a plurality of luminescent sheets  100  of different colors under different portions of keyboard well plate  30  to cause different keys, keygroups and keyboard areas to be illuminated by different colors. Another method for providing keys of different colors is to tint the optically transmissive material from which the keys are made, so that when the keys are illuminated by a luminescent sheet  100 , the key color will be a composite of the light from the luminescent sheet and the tint of the keys. Also, the optically transmissive keys from which the keys are made may be mixed with phosphors of different colors when illuminated by luminescent sheet  100 .  
         [0023]    A further variation of the method of illuminating a keyboard as described above is to manufacture top plate  20  of an optically transmissive material so that light from luminescent sheet  100  will transmit through the top plate to provide illumination of the top plate surface areas as well as the keys. Top plate  20  can be illuminated with a separate luminescent sheet  100  of a desired color by placing the separate luminescent sheet  100  under the surface area  22  of top plate  20 , such that the upper surface are  131  of luminescent sheet  100  is aligned with surface area  22  of top pate  20 , as illustrated in FIG. 4. Top plate  20  can also be made of an optically transmissive material that is tinted with a desired color and, or, mixed with phosphors to provide luminescence in response to light received from luminescent sheet  100 .  
         [0024]    In an alternative embodiment, luminescent sheet  100  can be adhered to the upper surface  31  of key board well plate  30 , as illustrated in FIG. 5. In this configuration, keyboard well plate  40  can be made of any opaque material as is usually used, because light from luminescent sheet  100  illuminates the keys more directly without the necessity of transmission through key board well plate  30 . Also, the substance used to adhere luminescent sheet  100  to upper surface  31  of keyboard well plate  30  need not be an optically transmissive material in this configuration. In this configuration the keypads  10  are made of optically transmissive material, and top plate  20  can also be illuminated as described above.  
         [0025]    An advantage of using a flexible luminescent sheet is the ability to provide illumination for non-traditional keyboards, such as ergonomic keyboards that are arcuate in shape in one or more spatial directions. Moreover, the methods of keyboard illumination disclosed herein can readily be adapted to any keyboard manufacturing process. This would enable a manufacturer of non-illuminated keyboards to quickly and inexpensively become a manufacturer of illuminated keyboards without developing an entirely new manufacturing process to accommodate specialized configurations. Further, the methods of the present invention disclosed herein can be implemented by any person of ordinary skill in the art to convert existing keyboards into illuminated keyboards. Moreover, the methods of the present invention disclosed herein can be applied to the manufacture of an illuminated mouse, by making the mouse buttons and exterior enclosure of an optically transmissive material and underlying these components with one or more luminescent sheets connected to a suitable power source.  
         [0026]    While this invention has been described with reference to the foregoing preferred embodiments, the scope of the present invention is not limited by the foregoing written description. Rather, the scope of the present invention is defined by the following claims and equivalents thereof.