Abstract:
An electronic sign which is particularly suited for end aisles, large merchandise, and the like. The electronic sign includes a frame, first and second displays in the frame which face opposite directions, a base for supporting the frame, and control circuitry for causing the first and second displays to display information.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to electronic signage and displays controlled by radio frequency (RF) signals, and more specifically to an electronic sign. 
   Food and general merchandise stores use large signs to promote their products. For example, grocery stores typically include displays for products grouped at the ends of aisles. 
   It would be desirable if these signs were electronic in order to more easily change the displayed information and to reduce labor costs associated with changing the signs. 
   SUMMARY OF THE INVENTION 
   In accordance with the teachings of the present invention, an electronic sign is provided. 
   The electronic sign includes a frame, first and second displays in the frame which face opposite directions, a base for supporting the frame, and control circuitry for causing the first and second displays to display information. 
   It is accordingly an object of the present invention to provide an electronic sign. 
   It is another object of the present invention to provide an electronic sign whose displayed information is easily changed via radio frequency (RF) communication. 
   It is another object of the present invention to provide an electronic sign which includes a display that is easily removed. 
   It is another object of the present invention to provide an electronic sign which includes a two-sided display. 
   It is another object of the present invention to provide an electronic sign which includes a stand which is adjustable in height. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a front view of the electronic sign; 
       FIG. 2  is a front view of the electronic sign configured with longer legs; 
       FIG. 3  is a perspective view of the electronic sign, showing insertion of a display; and 
       FIG. 4  is a block diagram of communication and control circuitry of the electronic sign. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to  FIGS. 1–3 , electronic sign  10  includes display portion  12  and base portion  14 . 
   Display portion  12  includes front and rear displays  16  and  18 , and frame  20 . 
   Front and rear displays  16  and  18  display promotional information, such as price information. Front and rear displays  16  and  18  may simultaneously display the same or different information. 
   Front and rear displays  16  and  18  may include liquid crystal displays (LCDs). Alternatively, front and rear displays  16  and  18  may include single sheets of electronic paper, such as the type provided by Gyricon, or electronic ink for signage display purposes. 
   Front and rear displays  16  and  18  slide into frame portion  20 , from a side or the top of frame  20 .  FIG. 3  illustrates insertion from the top of frame  20 . Frame portion  12  includes apertures  34  and  36  for receiving front and rear displays  16  and  18 . 
   Front and rear displays  16  and  18  couple to connector  22  in frame  20 . Connector  22  couples to communication and control circuitry  24  within base portion  14 . 
   Frame portion  20  includes holes  32  for receiving legs  26  of base portion  14 . 
   Base portion  14  includes foot section  28  which supports frame portion  12 . Foot section  28  is wide enough to provide a level of stability against falling over. 
   Base portion  14  also includes legs  26  and leg supports  30 . Bottom ends of legs  26  are inserted into leg supports  30 . Top ends of legs  26  are inserted into holes  26  within frame portion  20 . 
   Legs  26  may vary in length.  FIG. 2  shows a version of electronic sign  10  with longer legs  26 . 
   Legs  26  are hollow to facilitate passage of wiring  38  from connector  22  to communication and control circuitry  24 . 
   Turning now to  FIG. 4 , communication and control circuitry  24  is shown in more detail. Electronic sign  10  receives price and other promotional information from host computer  60 . 
   Communication and control circuitry  24  primarily includes antenna  40 , detector  42 , signal processing circuitry  44 , and microcontroller  46 . 
   Antenna  40  receives and transmits modulated RF signals. Antenna  40  is preferably a quarter-wave folded planar conductor which operates around a carrier frequency of 2.45 GHz. 
   Reception of downlink signals is similar to the method disclosed in commonly assigned U.S. Pat. No. 5,668,560. This patent is hereby incorporated by reference. 
   Detector  42  extracts an information signal from a modulated downlink carrier signal. Detector  42  is preferably a Schottky barrier-type silicon diode. 
   Signal processing circuitry  44  amplifies and demodulates the detected downlink signal to produce a downlink information signal. 
   Microcontroller  46  identifies on/off keyed data bits in the downlink information signal to generate data for display by display  14 . Microcontroller  46  also provides an uplink information signal. 
   Communication circuitry  24  may additionally include switch  48 , amplifier  50 , and digital modulator  52 . 
   Switch  48  routes the downlink signal to amplifier  50 . Switch  48  is controlled by microcontroller  46 . 
   Amplifier  50  amplifies an uplink signal from digital modulator  52 . Amplifier  50  is powered by energy in the 2.45 carrier signal of the downlink signal. 
   Digital modulator  52  produces the uplink signal from an uplink information signal provided by microcontroller  46 . Microcontroller  46  activates switch  48  to cause amplification and transmission of the uplink signal from digital modulator  52 . Microcontroller  46  may be programmed to activate switch  48  if sign  10  is placed in a location where unamplified passive communication is difficult. If microcontroller  46  does not cause switch  48  to route the incoming downlink signal to amplifier  50 , the uplink signal goes to antenna  40  unamplified. 
   Although the present invention has been described with particular reference to certain preferred embodiments thereof, variations and modifications of the present invention can be effected within the spirit and scope of the following claims.