Abstract:
A wireless communication device having a display screen with a holographic overlay. The holographic overlay includes an image that is visible when the display screen is viewed at predetermined angles. The holographic overlay may provide additional surface on the wireless communication device for marking and advertising, and may also provide security by preventing unintended viewers from seeing characters on the display screen. In one embodiment, the display screen includes a character screen, a lens, and a holographic overlay.

Description:
BACKGROUND OF THE INVENTION 
     The present invention is directed to a wireless communication device having a display and associated holographic overlay. 
     Wireless communication devices are becoming more popular in today&#39;s society. One reason for their increased popularity is their small size which allows a user to easily carry the device and use it in environments that were previously unavailable or inconvenient. The smaller device sizes introduce new challenges for the device manufacturers and service providers that were previously not encountered. 
     The size of the devices is now such that the name of the manufacturer or service provider is difficult to display or brand on the device. A common means of branding is to place the name on the face of the device in a conspicuous location such that it is seen by the user. However, with the decreasing device sizes, there is less usable space for placing the name. Therefore, new designs and locations are needed for clearly branding the phone without detracting from the functionality. 
     The smaller wireless communication devices are also now being used in crowded environments such as airports, restaurants, and the like. It is currently difficult to find an environment and location in which someone is not using a wireless communication device. Users often require privacy and security when using the devices in these crowded environments because confidential and sensitive information may appear on the display screen. The user may not want a person sitting beside them to peer over at the display screen and obtain this information. It would be advantageous for the display screen on the device to be seen by the user, yet prevent an unintended neighbor from viewing the display contents. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention includes a holographic overlay positioned proximate a display screen of a wireless communication device. The holographic overlay is positioned such that it has a first appearance when viewed at a first angle, and a second appearance when the display screen is viewed at a second angle. The holographic overlay may be substantially transparent at the first angle such that display characters appearing on the display screen are visible. When viewed at the second angle, the holographic overlay may substantially obscure the display characters. 
     The holographic overlay may provide previously unavailable surface area on the wireless communication device for advertising and other branding materials. The holographic overlay may also prevent an unintended viewer from seeing characters displayed on the display screen. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a wireless communication device in accordance with one embodiment of the present invention; 
     FIG. 2 is an exploded perspective view illustrating the elements of the display screen in accordance with one embodiment of the present invention; 
     FIG. 3 is a schematic view illustrating the production of a hologram for producing a holographic overlay in accordance with the present invention; 
     FIG. 4 is a schematic diagram illustrating a viewing region for observing characters on the display screen; 
     FIG. 5A is a display screen as seen when viewed within the viewing region; and 
     FIG. 5B illustrates the appearance of the display screen of FIG. 5A as seen from an angle outside of the viewing region. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to a display screen  31  having a holographic overlay  33  for use in a wireless communication device  10 . The holographic overlay  33  may prevent uninvited users from overseeing characters appearing on the display screen  31  and/or may also give additional area for advertising and other like branding features within a highly visible area of the wireless communication device  10 . 
     FIG. 1 illustrates one embodiment of a wireless communication device  10  applicable for use in the present invention. The wireless communication device  10  includes a display assembly  20  for displaying characters input and/or received by the user. The term “characters” is used herein to include alphanumeric characters as well as graphic images. Input keys  30  are positioned adjacent to the display assembly  20  for inputting and controlling the function of the device  10 . Input keys  30  may include specific characters such as numbers and letters, or may represent control functions such as “enter”, “on”, “off” and the like for controlling the device  10 . Control electronics, illustrated schematically as element  60  in FIG. 2, control the logic and processing of the device  10 . Control electronics  60  are well known to those working with wireless communication devices and will not be discussed herein. An outer housing  32  extends around the display assembly  20  and input keys  30 . In one embodiment, the outer housing  32  is constructed of a rigid material to protect the control electronics  60 . The embodiment illustrated in FIG. 1 is a portable cellular telephone that further includes a speaker  34  and microphone  36  for the user to partake in voice communications. 
     FIG. 2 illustrates one embodiment of the display assembly  20  that includes a display screen  31 , the holographic overlay  33 , and a lens  35 . Other embodiments of the display assembly  20  are also contemplated by the present invention including the display screen  31  and the holographic overlay  33  without a lens  35 . Another embodiment includes the lens  35  incorporated into the display screen  31  such that it is a unitary element. Also, the holographic image  39  may be manufactured into the display screen  31  or the lens  35 . The orientation of the display screen  31  may also be varied depending upon the specific embodiment. As illustrated in FIG. 2, display assembly  20  includes the holographic overlay  33  positioned between the display screen  31  and the lens  35 . In another embodiment, lens  35  may be positioned between the display screen  31  and the holographic overlay  33 . 
     Display assembly  20  is positioned in an opening within the outer housing  32 . The display screen  31  is operatively connected to the control electronics  60  for displaying characters to the user. A variety of display screen embodiments are contemplated by the present invention, two of which include a liquid crystal display and a CRT monitor. Lens  35  is constructed of a transparent material such that the user may be able to see the display screen  31 . Lens  35  may also magnify or manipulate the characters on the display screen  31  for easier viewing by the user. Additionally, lens  35  protects the display screen  31  and holographic overlay  33  from being damaged when placed on the outer surface of the display assembly  20 . 
     A holographic image  39  is positioned within the display assembly  20 . The image  39  is constructed such that it is visible to a viewer when the display assembly  20  is viewed from a specific angle or range of angles. The image  39  may either have the appearance of a two-dimensional or three-dimensional object. In one embodiment, image  39  displays the name, insignia, or other identifying indicia of the manufacturer or service provider thus branding the device  10 . 
     FIG. 3 illustrates a simplistic schematic view of forming the branding image  39  on the holographic overlay  33 . A coherent light source  100 , such as a laser, is directed onto a beam splitter  102  that splits the original beam into two separate beams. A first beam is directed to lens  112  that diffuses the light onto the object being recorded. This light reflects off the object onto the film plate of the holographic overlay  33 . The second beam is reflected from a mirror  104  through a diffusing lens  114  and onto the film plate of the holographic overlay  33 . The first beam and second beam are from the same light source  100  and have perfect intersection points when reaching the holographic display  33  thus creating a clear image of the object  110 . 
     In one embodiment, the holographic overlay  33  comprises a series of grooves formed on the surface of the recording medium that bend light rays in a manner similar to a prism. The grooves may be sized such that there are hundreds to thousands of grooves per millimeter. Another embodiment features the holographic overlay  33  constructed of variations throughout the depth of the overlay. The variations may include light and dark or refractive index differences that produce the visible representation of the object  110 . Hybrid combinations of the embodiments may also be used, such as a layered grating display in which two or more overlays each having surface grating are combined together forming a display having variations throughout the depth. Layered overlays  33  may also be used for displaying multi-images that are each visible when viewed at a predetermined angle or range of angles. 
     The holographic image  39  may be constructed in a manner of different embodiments. In one embodiment, the image  39  is produced by embossing. A series of grooves are pressed into one of the elements of the display assembly  20  to create the image. Embossed holograms may further be coated with aluminum to enhance the appearance and brightness of the image. The holographic image  39  may be positioned on the overlay  33 , in the display screen  31  or the lens  35 . In the embodiments in which the image  39  is on the lens  35  or screen  31 , the display assembly  20  may not include a separate overlay layer  33 . 
     The image  39  may be visible within the holographic overlay  33  from either light transmitted from the device  10  through the display assembly  20  or light from an external source reflected from the overlay  33 . As schematically illustrated in FIG. 2, device  10  may include a light source  41  for illuminating the display assembly  20  such as during low ambient light conditions. Light emanating from the light source  41  passes through the display assembly  20  causing the image  39  to be visible. In another embodiment, display screen  31  may be a light emitting panel that is illuminated when in use. Alternatively, external light may be directed onto the display assembly  20  and reflect off the holographic overlay  33  to display the image  39 . 
     The holographic display  33  is designed such that the image  39  is not visible when the display assembly  20  is viewed from certain angle or range of angles. This results in display screen  31  having different appearances when viewed from different angles. One embodiment is illustrated in FIG. 4 in which a viewing region  22  defines the area in which the image  39  is not visible and the characters entered on the display screen  31  can be viewed by the user. In the embodiment illustrated, the viewing region  22  is aligned such that the user can longitudinally angle the display assembly  20  without obscuring the characters. However, observing the display assembly  20  laterally from the sides results in the characters being obscured by the image  39 . This configuration allows the user to work with substantial privacy in an environment where persons are positioned laterally on one or both sides. The viewing region  22  may be adjusted to accommodate a variety of angles and range of angles. In one embodiment, the viewing region  22  encompasses about sixty degrees aligned about an axis drawn normal through the center of the display assembly  20 . Additionally, the viewing region  22  may be aligned laterally or longitudinally about the display assembly  20 . In another embodiment, the viewing region  22  has a substantially cone-shape in which a point of the cone is positioned about the center of the display assembly  20 . 
     The viewing region  22  may be aligned such that the image  39  completely obscures the characters on the display assembly  20  when viewed from outside of the viewing region  22  and the image  39  is not visible when viewed from within the region  22 . This embodiment is illustrated in FIGS. 5A and 5B. When viewer  50  is aligned with the display assembly  20  to be within the viewing region  22 , the characters are visible and the branding image  39  is not visible as in FIG.  5 A. When the viewing angle changes such that the viewer  50  is outside of the viewing region  22  as in FIG. 5B, the characters are completely obscured by the branding image  39 . 
     In another embodiment, the branding image  39  may become increasingly visible as the viewing angle moves away from the center of the viewing region  22 . Both the characters on the display assembly  20  and the image  39  may be visible at the same angle within the viewing region  22 . As the angle moves from the center of the viewing region, the image  39  becomes more visible and begins to obscure the characters. Eventually, the angle becomes such that the image  39  completely blocks the characters. In one embodiment, the contrast ratio between the characters and the background of the display screen  20  falls from more than 100:1 when viewed perpendicular to the display screen  20  to less than 10:1 when viewed at ±30° in the lateral direction because the image  39  becomes more prominent. 
     More than one image  39  may also be visible on the display assembly  20 . In one embodiment, a first image  39  is visible from a first range of viewing angles, and a second image  39  is visible within another range of viewing angles. In another embodiment, both images  39  may be visible at the same angle, or range of angles. Another embodiment features an image  39  displayed across the entire display assembly  20  when light  41  is not activated. When activated, light  41  causes the image  39  to be obscured such that the user can clearly see the characters on the display screen  31 . A variety of embodiments having multiple images  39  are available and considered by the present invention. 
     The display screen  31  may be divided into separate sections having different displays or different images  39 . As illustrated in FIGS. 5A and 5B, the display screen  31  is divided into an active region  26  and an inactive region  24 . Active region  26  includes the space where characters are displayed and viewed by the user. In the embodiment illustrated, the active region  26  includes a first image  39 . Inactive region  24  is the peripheral edge of the display screen  20  that is not used for displaying characters and borders the active region. Inactive region  24  may include a separate image  39 , or may include a permanent image that is not dependent on the viewing angle. 
     As illustrated in FIG. 2, one embodiment features the holographic display  33  positioned between the display screen  31  and the lens  35 . Other placements of the elements are also contemplated by the present invention. One embodiment features the holographic overlay  33  positioned on the outer side of the lens  35 . The display assembly  20  may be positioned within the outer housing  32  such that it is easily removable to customize the appearance of the device  10 . Users may desire to use different holographic displays  33  at different times or during different environments. By way of example, the user&#39;s favorite basketball team may be displayed on the branding image  39  during basketball season, and replaced by the favorite football team as necessary. Additionally, straight-forward replacement and change-out of the holographic display  33  allows the manufacturer to more readily tailor the appearance of the device  10  to meet the demands of the user. 
     The term “wireless communication device” denoted by element number  10  used herein refers to a variety of different devices. Devices may include: a cellular radiotelephone; a Personal Communications System (PCS) terminal that may combine a cellular radiotelephone with data processing, facsimile and data communications capabilities; a Personal Digital Assistant (PDA) that can include a radiotelephone, pager, Internet/intranet access, Web browser, organizer, calendar and/or a global positioning system (GPS) receiver. The term wireless communication device  10  also encompasses computing devices, such as a personal computer, laptop computer, or palmtop computer, that includes a communications interface for communicating with other devices. 
     The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.