Patent Publication Number: US-2006008277-A1

Title: Optical communication system and receiving apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      The present application is based on and claims the benefit of priority of Japanese Patent Application P2004-2044.91 filed on Jul. 12, 2004, the entire contents of which are incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to an optical communication system and a receiving apparatus.  
      2. Description of Related Art  
      An inventory tag is set to a shelf in a supermarket or a convenience store, and the inventory tag corresponds to a commodity displayed in the shelf. Customers can see easily the name of the commodity, a unit price, the amount, special sale information and so on, on the inventory tag. In general, a card-type inventory tag made of paper or other materials is used as the inventory tag, and the information such as the name of the commodity, the unit price and so on are printed on the inventory tag by a printer.  
      If this inventory tag is used, when the unit price needs to be changed for a next day sale, a shop assistant has to change the tag corresponding to the commodity for the next day sale after the shop is closed. Thus, if there are a large number of changes, it is time-consuming and it requires a large amount of work. Further, if a special sale is taking place only in a particular time, and many commodities are on sale, it would be difficult to deal with all the necessary changes within a limited time. Further, when significant changes to displays take place at different seasons of a year, many inventory tags need to be changed, and a similar problem would occur.  
      Consequently, to cope with such problems, an electronic inventory tag system has been developed, which uses an electronic inventory tag as the inventory tag to electronically rewrite commodity data.  
      The electronic inventory tag used in the electronic inventory tag system includes a liquid crystal display, a data receiving section for receiving data from a host machine, a solar battery, and so on. The electronic inventory tag is driven by electric power generated by the solar battery, and changes the unit price displayed in the liquid crystal display based on a signal received from the host machine by radio communication and/or infrared data communication.  
      As the host machine, a host computer located in a back of a store, for example, can be used. The host computer transmits the signal such as a change of the unit price to the electronic inventory tag(s). In this case, a plurality of radio communication apparatuses which are connected to the host computer are located on the ceilings of sales rooms so that the host computer executes radio communication with the electronic inventory tag(s) through these radio communication apparatuses.  
      A hand terminal can be another example of the host machine, as disclosed in Japanese Laid-Open Publication 2001-109956. The hand terminal comprises a scanner for optically reading a bar-coded commodity code, a keyboard, a radio communication apparatus, and so on. The hand terminal executes radio communication with the electronic inventory tag through the radio communication apparatus.  
      Such a conventional electronic inventory tag system, however, has a problem. Since the system requires a receiving apparatus which is used only for radio communication in order to achieve radio communication between the electronic inventory tag and the host machine, the structure becomes complicated.  
      Accordingly, the object of the present invention is to simplify the structure of the receiving apparatus for data communication, which has a solar battery.  
     SUMMARY OF THE INVENTION  
      According to the present invention, an optical communication system is provided which includes: (i) a transmitting apparatus which includes a light source, and which converts digital data into an optical signal and transmits the optical signal by controlling the light source to fluctuation in accordance with the optical signal, and (ii) a receiving apparatus for receiving the optical signal and converting the optical signal back into the digital data. The receiving apparatus converts optical energy into electrical energy by a solar battery for powering the receiving apparatus, utilizes a fluctuation of generation of electricity of the solar battery, which occurs in accordance with the fluctuation of the light source transmitting the optical signal, as a fluctuation signal, and converts the fluctuation signal into the digital data.  
      In addition, according to the present invention, a receiving apparatus is provided which converts optical energy into electrical energy with a solar battery for powering the receiving apparatus, utilizes a fluctuation of generation of electricity, which is generated in accordance with an optical pulsing signal received by the solar battery, as the fluctuation signal, and converts the fluctuation signal into digital data. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:  
       FIG. 1  is a structural diagram schematically showing an electronic inventory tag system of an embodiment of the present invention;  
       FIG. 2  is an elevational view showing the electronic inventory tag;  
       FIG. 3  is a circuit diagram showing a circuit structure of the electronic inventory tag;  
       FIG. 4  is a time chart of various voltages of the electronic inventory tag;  
       FIG. 5  is a perspective view showing a hand terminal;  
       FIG. 6  is a block diagram showing an electronic installation of the hand terminal;  
       FIG. 7  is a block diagram showing an electronic installation of a store computer;  
       FIG. 8  is a flow chart showing a data transmission process of a unit price;  
       FIG. 9  is a flow chart showing a process of changing of a unit price with respect to the hand terminal;  
       FIG. 10  is a flow chart showing a data transmission process of a unit price; and  
       FIG. 11  is a flow chart showing a process of changing a unit price with respect to the electronic inventory tag.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      An embodiment of the present invention will be explained with reference to the drawings. The embodiment of the present invention applies an optical communication system using a solar battery to an electronic inventory tag system used in a store such as a supermarket.  
      [System Outline] 
       FIG. 1  is a structural diagram schematically showing an electronic inventory tag system  1  of an embodiment of the present invention. As shown in  FIG. 1 , an electronic inventory tag system  1  comprises a plurality of electronic inventory tags  2  as receiving apparatuses for displaying commodity data such as a commodity price, a hand terminal  3  as a transmitting apparatus for transmitting the commodity data to the electronic inventory tags  2 , a store computer  4  as a host machine for delivering the commodity data to the hand terminal  3 , and so on. One or more hand terminals  3  can be provided. The electronic inventory tag system  1  executes optical communication between the hand terminal  3  and the electronic inventory tags  2  by use of a change of the amount of electricity generated by a solar battery  13  (explained later) in the electronic inventory tags  2  in accordance with a light emitted from the hand terminal  3 .  
      [Electronic Inventory Tag  2 ] 
       FIG. 2  is an elevational view showing one of the electronic inventory tags  2 . The electronic inventory tag  2  is installed at a position of a shelf (not shown) corresponding to a commodity, and displays commodity data such as unit price data of the corresponding commodity. The electronic inventory tag  2  has a rectangular housing  11 . The housing  11  contains the solar battery  13 , and a liquid crystal display (LCD)  12  as an indicator for displaying the commodity data such as the unit price data. In addition, a commodity data card  14 , on which a name of the commodity and a bar-code are printed, is fixed to the housing  11 . The bar-code is a bar-coded commodity code. Although the liquid crystal display  12  is used as the indicator in the embodiment of the present invention, a LED display, an EL display, or another display can be applicable. Also, either a monochrome display or a color display can be used.  
      The solar battery  13  is a power source which converts received optical energy to electrical energy. Since the structure of solar batteries is well-known, a detailed explanation thereof will be omitted. The electronic inventory tag  2  is driven by the electrical energy generated by the solar battery  13 ; that is, the solar battery  13  produces a drive power of the electronic inventory tag  2 .  
       FIG. 3  is a circuit diagram showing a circuit structure of the electronic inventory tag  2 . The electronic inventory tag  2  comprises a microcomputer  21  which contains a CPU (Central Processing Unit) for intensively controlling each part, a ROM (Read Only Memory) for storing fixed data, such as computer programs, in advance, and a RAM (Random Access Memory) for rewritably storing various data and for functioning as a working area so that the microcomputer  21  can control each part.  
      A display controller  23  for driving the liquid crystal display  12  is connected to the microcomputer  21  through a bus line  22 . A non-volatile memory  24  comprising a rewritable EEPROM (Electrically Erasable Programmable Read Only Memory) is connected to the microcomputer  21  through the bus line  22 . In the non-volatile memory  24 , a unit price memory area (not shown) is formed, where data such as a unit price to be displayed in the liquid crystal display  12  is stored as digital data. The display controller  23  receives the digital data such as the unit price stored in the non-volatile memory  24 , converts the digital data into data suitable for display, and displays the data in the liquid crystal display  12 .  
      A data receiving circuit  25  connected to the solar battery  13  is connected to the microcomputer  21 . When the solar battery  13  receives a plurality of optical pulsing signals, the data receiving circuit  25  utilizes a fluctuation of generation of electricity from the solar battery as a fluctuation signal in accordance with the received optical signal. A comparator  26  is provided in the data receiving circuit  25 . A plus input terminal  26   a  of the comparator  26  is connected to an output terminal  13   a  of the solar battery  13  through a resistance  27 , and is also connected to the other output terminal  13   b  of the solar battery  13  through a resistance  28 . A minus input terminal  26   b  is connected to an output terminal  13   a  of the solar battery  13  through a resistance  29 , and is also connected to the other output terminal  13   b  of the solar battery  13  through a resistance  30 . An output terminal  26   c  of the comparator  26  is connected to an interrupt terminal  21   a  of the microcomputer  21  and to a data receiving terminal  21   b.    
      As an amount of light exposed on the solar battery  13  changes so that an amount of electricity generated by the solar battery  13  changes, a voltage in the receiving circuit  25  changes. When a certain amount of light from a lighting installation of a shop (not shown) shines on the solar battery  13 , for example, as shown in  FIG. 4 , so that an optical pulsing signal is emitted to the solar battery  13 , an output voltage A (a generated voltage indicated as A in  FIG. 3 ) of the solar battery  13  changes to a pulsing voltage. The output voltage A of the solar battery  13  is divided by the resistances  29  and  30 , and is stored in a condenser  31  so that the output voltage A of the solar battery  13  is input as a reference voltage B (indicated as B in  FIG. 3 ) of an analogue signal into the minus input terminal  26   b  of the comparator  26 . At this time, a voltage C (indicated as C in  FIG. 3 ), which is a divided voltage of the output voltage A by the resistances  27  and  28 , is input as a pulsing analogue signal into the plus input terminal  26   a  of the comparator  26 . Then, these input voltages B and C (the analogue signals) are compared in the comparator  26  and a fluctuation of the output voltage A is output into the microcomputer  21  as a pulse of voltage D (a digital signal indicated D in  FIG. 3 ). The pulse of voltage D output by the comparator  26  is the fluctuation signal explained earlier. The microcomputer  21  stores the pulse of voltage D as digital data, that is, a data row of a combination of ┌1┘ and ┌0┘.  
      [Hand Terminal  3 ] 
       FIG. 5  is a perspective view showing a hand terminal  3 . As shown in  FIG. 5 , a liquid crystal display  42  and a key board  43  are provided on an upper surface of a body case  41 . The key board  43  comprises function keys  43   a , numeric keypads  43   b , transmission keys  43   c  and so on. A barcode scanner  44  as an optical reading apparatus is provided in the body case  41  and a barcode reading window  45  is formed under the body case  41 . The barcode scanner  44  comprises a LED (Light Emitting Diode) array  46  (see  FIG. 6 ) to emit a light to a barcode from the LED array, and reads a reflected light received by a CCD  47  (Charge Coupled Device, see  FIG. 6 ). The hand terminal  3  is made to be portable.  
       FIG. 6  is a block diagram showing an electronic installation of the hand terminal  3 . The hand terminal  3  comprises a microcomputer  51  which contains a CPU for intensively controlling each part, a ROM for storing fixed data such as computer programs, in advance, and a RAM for rewritably storing various data, and for functioning as a working area, so that the microcomputer  51  controls each part.  
      A display controller  53  for driving the liquid crystal display  42 , a keyboard controller  54  for outputting a signal from the key board  43 , a scanner controller  55  for driving the CCD  47  and the LED array  46 , and so on, are connected to the microcomputer  51  through a bus line  52 . Further, a radio transmission interface  56  for executing radio communication with a store computer  4 , a non-volatile memory  57  comprising a rewritable EEPROM, and so on, are connected to the microcomputer  51  through a bus line  52 . In the non-volatile memory  57 , for example, a commodity master file (as explained later), which is delivered from the store computer  4 , is stored.  
      [Store Computer  4 ] 
       FIG. 7  is a block diagram showing an electronic installation of a store computer  4 . The store computer  4  has a microcomputer  61  comprising a CPU, a ROM, a RAM, and so on, so as to execute radio communication between the hand terminal  3  and a radio transmission interface  63  connected to the microcomputer  61  through a bus line  62 .  
      A key board  65 , an indicator  66 , and a HHD (Hard Disk Drive)  67  are connected to the microcomputer  61  through the bus line  62  and an I/O apparatus controller  64 . The HHD  67  stores a program for controlling the CPU of the microcomputer  61 , the commodity master file, and so on. The commodity master file stores a commodity code corresponding to commodity data such as a name of the commodity and a unit price.  
      [Various Processing] 
      Various processing executed by the microcomputers  21 ,  51 , and  61  of an electronic inventory tag system  1  in accordance with computer programs will be explained with an operation procedure by a shop assistant.  
       FIG. 8  is a flow chart showing a data transmission process of a unit price.  
      To change a unit price displayed in the liquid crystal display  12  of the electronic inventory tag  2 , the shop assistant changes price data of the commodity master file stored in the HDD  67  by operating the keyboard  65  at the store computer  4 , and then a delivering operation of the unit price data is executed.  
      As shown in  FIG. 8 , if the delivering operation of the price data is executed by the shop assistant, the commodity master file containing the unit price data stored in the HHD  67  is transmitted to the hand terminal  3  (step S 1 ) via the radio transmission interface  63 .  
      If the commodity master file from the store computer  4  is received in the hand terminal  3  (Y of step S 11 ), the commodity master file is stored in the non-volatile memory  57  (step S 12 ). At this time, if a commodity master file already stored in the non-volatile memory  57 , the already stored master file is overwritten by the received master file. Thus, the unit price data of the commodity is delivered from the store computer  4  to the hand terminal  3 .  
       FIG. 9  is a flow chart showing a process of changing a unit price with respect to the hand terminal  3 .  
      Next, the shop assistant uses the hand terminal  3  to execute, with the barcode scanner  44 , a scanning operation of a barcode printed on the commodity data card  14  of the electronic inventory tag  2 .  
      As shown in  FIG. 9 , if the commodity code is read and output by the barcode scanner  44  operated by the shop assistant (Y of step S 21 ), the commodity master file stored in the non-volatile memory  57  is searched and the unit price data of the commodity and so on are acquired (step S 22 ). Then, the acquired unit price data and so on are displayed in the liquid crystal display  42  (step S 23 ).  
      After the shop assistant confirms the unit price data and so on displayed in the liquid crystal display  42 , he/she places the hand terminal  3  close to the electronic inventory tag  2  so as to expose the solar battery  13  of the electronic inventory tag  2  to a light emitted from the LED array  46  of the barcode scanner  44 . Then, he/she presses the transmission key(s)  43   c  on the keyboard  43 .  
      If the transmission key(s)  43   c  on the keyboard  43  is/are pressed by the shop assistant (Y of step S 24 ), a unit price data transmission process is executed to transmit the commodity unit price data to the electronic inventory tag  2  by optical communication (step S 25 ).  
      The unit price transmission process in step S 25  will be explained with reference to  FIG. 10 . As shown in  FIG. 10 , lighting of the LED array  46  is controlled in accordance with a digital value which makes up the digital commodity code acquired in step S 22 . To be specific, since the digital data consists of a data row of digital values (┌1┘ and ┌0┘), the lightning is executed in accordance with the first digital value of the data row, and then is executed in accordance with the following digital value. If the digital value is ┌0┘ (Y of step S 31 ), the LED array  46  lights up for a predetermined time (step S 32 )). If the digital value is ┌0┘, instead of ┌1┘ (N of step S 31 ), the LED array  46  turns off for a predetermined time (step S 34 ). If the digital data is not the last one in the data row and data still remains (N of step S 33 ), the process goes back to step S 31 , and is executed with respect to a next digital value of the data row. The digital commodity code is thus converted into an optical pulsing signal by lightning up or turning off of the LED array  46  with respect to each digital value, and the optical pulsing signal is transmitted to the electronic inventory tag  2 .  
       FIG. 11  is a flow chart showing a process of changing a unit price with respect to the electronic inventory tag  2 .  
      If the electronic inventory tag  2  receives the optical pulsing signal from the hand terminal  3  (Y of step S 41 ), the optical pulsing signal is converted back into the original digital unit price data, and is stored in a unit price memory area of the non-volatile memory  24  (step S 42 ). If a unit price data is already stored in the unit price memory area, the already stored unit price data is overwritten by the received unit price data. Since a converting method of an optical pulsing signal into digital data is already explained, a detailed explanation thereof will be omitted.  
      Then, the unit price data stored in the unit price memory area is displayed in the liquid crystal display  12  (step S  43 ), and the unit price data flashes a predetermined number of times (step S 44 ) in order to generate a notification of a successful receipt of the optical pulsing signal and a completion of data conversion. When the flashing is over, the display returns to normal.  
      As explained above, according to the embodiment of the present invention, the commodity data is digital data, and the electronic inventory tag  2  is a receiving apparatus that includes the liquid crystal display  12  as an indicator for displaying information, and the microcomputer  21  and display controller  23  which act as a display control section for displaying the commodity data on the liquid crystal display  12  in accordance with the digital data converted from the optical signal. In addition, since the electronic inventory tag  2  having the solar battery  13  as a driving source executes the optical transmission by receiving the optical signal from the hand terminal  3  as a transmitting apparatus, a structure for data transmission of the electronic inventory tag  2  can be simplified compared to a conventional receiving apparatus which requires a radio communication apparatus used for data transmission only.  
      Further, according to the embodiment of the present invention, the transmitting apparatus (hand terminal  3 ) comprises: the LED array  46  as a light source and the barcode scanner  44  as an optical reading apparatus for reading the commodity code by use of a reflection of a light emitted by the LED array  46  toward the bar-coded commodity code, the non-volatile memory  57  as a memory for storing the digital commodity code corresponding to the commodity data, and the microcomputer  51  which acts as a control unit and acquires the commodity data stored in the non-volatile memory  57  corresponding to the commodity code which is read by the barcode scanner  44 , converts the acquired commodity data (the unit price data in the embodiment of the present invention) into the optical signal, and transmits the optical signal. In addition, the hand terminal  3  transmits the optical signal to the electronic inventory tag  2  as the receiving apparatus by optical communication by using the LED array  46  contained in the barcode scanner  44 . The LED array  46  is thus used as the light source of the optical communication as well as the light source for the barcode scanner  44 . Thus, the structure of the hand terminal  3  can be simplified compared to a conventional transmitting apparatus which requires a radio communication apparatus used only for transmission.  
      Still further, according to the embodiment of the present invention, the store computer  4  serves as a host machine for storing the commodity code corresponding to the commodity data, and transmits the data to the radio transmission interface  56  of the hand terminal  3  through the radio transmission interface  63  (the radio interfaces  56  and  63  being means for enabling data communication between the hand terminal  3  as the transmission means capable of data-transmission between the hand terminal  3  as the transmitting apparatus and the store computer  4 , the hand terminal  3  stores the commodity data in the non-volatile memory  57 , in correspondence with the commodity code received from the store computer  4  by data transmission. With this structure, data stored in a plurality of hand terminals  3  can be changed all together by data transmission from the single store computer  4 .  
      Yet still further, according to the embodiment of the present invention, since the electronic inventory tag  2  generates a notification of the receipt of the optical signal, the operator (the shop assistant) can confirm the completion of data transmission.  
      The embodiment of the present invention is described in conjunction with a specific example of the optical communication system using the solar battery  13  in which the electronic inventory tag  2  as the receiving apparatus is applied to the electronic inventory tag system  1 , but the present invention is not limited to this example. The present invention can be applied to any system having a combination of a receiving apparatus using solar power and a transmitting apparatus having a light source.  
      Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.