Abstract:
A thin, flat, self-contained electronic display unit of substantially the same width and length as a standard letter-sized sheet of paper, with a flat display screen, an input port for receiving data from a selected computer, electronic circuitry for storing inputted data and making it available to the screen, and command buttons or keys enabling the user to select stored data for display on the screen.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a portable electronic display unit for receiving and storing data from any selected computer, and for displaying stored data on command but without the user&#39;s possibility of changing the stored data in any way. 
     The present display unit is a retrieval and display-only device for electronic image data that has already been stored elsewhere, such as in any of central database, single computer or another unit that might be present in an office or school. As such, it answers the need for a simplified, portable, display only device capable of accessing data from multiple sources without the complexities attendant to a personal computer designed for many functions besides reading data from other computers. Multiple units in one environment increase the ease of information dissemination. 
     2. Prior Art 
     Electronic books are disclosed in the following U.S. patents: Rubincam U.S. Pat. No. 4,159,417 and Gaston U.S. Pat. No. 5,956,048. In Rubincam the digitally encoded contents of a book are stored in a memory which is removably insertable into the housing of the electronic book. In Gaston the electronic book is plugged into a mated downloading stand from which the encoded contents of a book are downloaded into the electronic book. 
     Yianilos U.S. Pat. No. 5,153,831 discloses a device having a display screen, an electronic memory with compressed text, and a keyboard for formulating words that are to be searched in that text for display on the screen along with adjoining words as they occur in the text. Borssuk U.S. Pat. No. 5,475,399 discloses a relatively thick, box-like device with a display screen, various keys for controlling the screen display, including keys to change the font size, and an insert port for receiving a memory, such as an EPROM, microfloppy or CD ROM. 
     BRIEF SUMMARY OF THE INVENTION 
     The present display unit is designed for the input of data stored in any computer, whether the user&#39;s or anyone else&#39;s to which the user has authorized access, for read-only display by the user at his or her convenience. In a large office it reduces paperwork by providing a convenient, paper-less way for a worker to access and read the contents of files from a central data base or network. 
     Preferably, the present display unit is a thin, flat device of substantially the same size as a standard letter-size sheet of paper, so the user&#39;s experience with this device approaches the familiar “look-and-feel” of actually reading paper documents. 
     A principal object of the present invention is to provide a novel and simplified display unit for enabling the user to conveniently read data stored in its internal memory but with no possibility of altering that data in any way. The user has mobile access to files, and information without carrying “paper files.” 
     Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment thereof, shown in the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the present display unit, taken from in front of the screen; 
     FIG. 2 is an exploded perspective view of the display unit, taken from in front of the screen, with the base and cover of its housing separated to show internal components; 
     FIG. 3 is a view similar to FIG. 2, but taken from behind the screen; and 
     FIG. 4 is a flow diagram showing the operation of the present display device 
     FIG. 5 is a perspective view of a unit as the screen for a laptop computer. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the particular arrangement shown since the invention is capable of other embodiments. 
     Referring first to FIG. 1, viewed from the outside the present display unit has a thin, flat, letter-size housing or casing made up of a rectangular base  10  and a similar front or top cover  11  detachably connected to the base in any suitable fashion and covering it when the display unit is in use. 
     The cover  11  presents a flat LCD (liquid crystal display) panel or screen  14  of substantially rectangular outline. For supporting the screen  14  the cover has a rectangular frame with opposite, narrow, flat side walls  15  and  16 , a narrow, flat top wall  17 , and a narrow, flat bottom wall  18 , and a border for the screen  14  with narrow, flat front segments  15   b ,  16   b ,  17   b , and  18   b  which extend in from the correspondingly numbered side, bottom and top walls of the frame. Preferably, the frame is substantially the same size as a standard letter-size sheet of paper, i.e., 8.5 inches wide by 11 inches long, so that the user handling or viewing it receives a mental impression similar to what he or she would get while reading from a standard letter-sized sheet of paper. 
     The base  10  of the housing has opposite side walls  115  and  116 , a top wall  117 , and a bottom wall  118  which merge smoothly with the correspondingly numbered (minus 100) walls of the cover when it is closed, as shown in FIG.  1 . 
     On the left front segment  15  of the cover near the top are LED&#39;s  20 ,  21 ,  22  and  23  for indicating various functions associated with the display unit, such as “power,” “battery,” “memory,” and “test.” On the right front segment  16 b of the cover are manually operable push-buttons  24 ,  25 ,  26 ,  27  and  28  for initiating various commands to the electronic circuitry that determine what appears on the screen  14 , such as “file,” “document,” “next,” “back,” and “system.” Also on the right front segment  16 b near the top is located a mouse-like scroll bar  29  which the user may slide up and down to quickly locate a document, file or particular line of text displayed on the screen  14 . 
     Referring to FIGS. 2 and 3, the base  10  supports on the inside of the housing the following electronic components of the present display unit: a microprocessor  30 , memory chips,  31 , a battery pack  32 , and a microprocessor  34 . A data input port  35  of known design (FIG. 2) is located in the bottom wall  118  of the base. A flexible multi-conductor cable  37  connects the output of microprocessor  30  to the LCD screen  14 . The microprocessors  30  and  34 , memory chips  31 , and various other components of the display unit&#39;s electronic circuitry are on a circuit board  38  located on the inside of base  10 . 
     On the back or inner side of the cover  11  a circuit board  40  carries a backup battery  41  for the RAM, a co-processor  42 , chips  43  for sound and infra-red functions, and various other electronic components. A backup power input terminal  44  (FIG. 3) is located in the top wall  17  of the cover. 
     In the use of this device, the user can take it to the location of any computer whose data the user wants to access at his or her convenience. This can be the user&#39;s own desktop computer or portable computer, or a computer to which the user has authorized access, or a central network or another electronic image display unit. The user by a well known technique downloads data from that computer into the user&#39;s portable display unit via the input port  35 . That data now is available for display on the screen  14  any time the user chooses to do so. Thus, an abundance of information is readily and conveniently available to the user without the exchange of any paper documents. Since the present display unit is limited to read-only operation, there is no possibility for the user to alter or corrupt the downloaded data in any way. 
     The flow chart of FIG. 4 is self-explanatory and does not require extensive reiteration. Depressing FILES displays all files loaded into memory; depressing DOC. displays all documents in a selected file; depressing NEXT advances to next document in file; depressing BACK returns to previous document in file. 
     FIG. 5 shows the unit as a removable screen for a laptop computer. The unit functions as normal after removal.