Abstract:
A multiple technology data reader, for reading bar code labels and RFID tags. The multiple technology data reader includes a bar code reader and a radio frequency identification (RFID) reader, connected to a host computer via a computer bus, such as a universal serial bus (USB). The bar code reader and the RFID reader communicate with the host computer through logically independent data pipes and device drivers. Compound, composite, or complex interface implementations are possible. A single electronic interface may be configured to allow a single host computer to logically communicate with the bar code and RFID readers as either separate independent readers, or as a single cooperative multiformat label/tag data reader. Thus, the bar code and RFID readers may be operated independently, or powered and operated simultaneously.

Description:
BACKGROUND OF THE INVENTION 
     The field of the present invention generally relates to optical systems for data reading and radio frequency identification (RFID) systems for remote identification of physical objects. More particularly, the field of the present invention relates to a multiple technology data reader for reading bar code labels and RFID tags. 
     Optical reading systems are widely used to read data, in the form of bar codes or other encoded symbols, printed on various objects. These systems may be used for a wide variety of applications, such as inventory control and point-of-sale transactions in retail stores. 
     Optical reading systems may employ an optical reader that illuminates a bar code (for example) and detects light reflected from the bars and spaces of the code. In one type of optical reading system, an optical beam of light produced by a laser diode is used to scan the bar code symbol. The bars of the code absorb light, while the spaces of the code reflect light. The resulting pattern of reflected light is detected by circuitry within the optical reader. The reflected light can be detected by a photocell, photodiode, CCD array, or CMOS array sensor. 
     After the bar code data is received by the optical reader, the detected signal may be subject to filtering, amplification, digitization and decoding. The detected signal may be transmitted to a processor or decoder located within the optical reader, or to a separate device such as a personal computer. In systems where the signal is conveyed to a separate device, the optical reader may be connected to the external data processor by means of cables or via a wireless communication link. The wireless communication link can be implemented using radio frequency (RF) equipment or infrared (IR) transmitters and receivers, for example. 
     In retail stores, optical reading systems may be set up at check-out stands and may be built into a horizontal check-out counter, so that items to be purchased can be placed on a counter, deck or conveyor, and then moved through an optical reading area. Alternatively, the optical reader may be a handheld device, in the shape of a wand or gun. Typically, in operation these handheld devices are pointed or aimed at the retail item, so that a wide range of information, including price, may be read from the object. 
     RFID systems can be used to identify retail items by reading electronic information stored within tags or labels on the items. These systems can be used to remotely identify physical objects by the response signal sent back by the tag. 
     An RFID system typically employs at least two components, a “transponder” or “tag,” which is attached to the physical item to be identified, and a “reader,” which sends an electromagnetic signal the transponder and then detects a response. Typically, the reader emits a RF signal which is received by the transponder, after the transponder comes within an appropriate range. In response to the signal from the reader, the transponder sends a modulated RF signal sent back to the reader. The reader detects this modulated signal, and can identify the transponder by decoding the modulated signal. After identifying the transponder, the reader can either store the decoded information or transmit the decoded signal to a computer. 
     The transponder used in an RFID system may be either “passive” or “active.” A passive transponder can be a simple resonant circuit, including an inductive coil and a capacitor. Passive transponders are generally powered by the carrier signal transmitted from the reader. Active transponders, on the other hand, generally include transistors or other active circuitry, and require their own battery source. 
     In some retail environments, both bar code labels and RFID tags are attached to various retail items. In these environments an optical reader is needed to read the bar code label, and a separate RFID reader is needed to detect and identify the RFID tag. Without a dual-technology device embodying both bar code and RFID reading functionality, two separate devices would be needed to read both bar codes and RFID tags. Thus, there is a present need for a dual-technology bar code/RFID reader. 
     One example of a hand-held dual technology identification tag reading head, that can read both bar codes and RFID tags is described in U.S. Pat. No. 5,382,784, issued to Eberhardt. However, the present inventor has recognized that the system described in that patent has several drawbacks. For example, in that system, in order to operate the hand-held reader, a user must selectively actuate either the bar code reader or RFID tag reader. Moreover, at any given time, only one of readers is powered. Therefore, simultaneous operation of both the bar code reader and the RFID tag reader is not possible. In addition, when the RFID reader is selected, the output signal from the RFID reader must be converted to a format corresponding to the output signal from the bar code reader, in order to be fed into a single input port of a data receiver. 
     Thus, the present inventor has determined it would be advantageous to provide a dual-technology bar code/RFID reader which is capable of reading bar codes and RFID tags simultaneously, and which is more versatile than the previously described devices. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a multiple technology data reader for reading optical code labels and RFID tags. In one embodiment, the multiple technology data reader includes an optical code reader sub-system and an RFID reader sub-system, each electronically connected to a device microcontroller. The device microcontroller includes a device interface for the bar code reader subsystem, and a device interface for the RFID reader subsystem. Both of these device interfaces are connected to a device communications, control and power unit. The device microcontroller is connected to a host computer via a computer bus, such as a universal serial bus (USB). 
     In another embodiment, the multiple technology data reader includes an optical code reader and an RFID reader, each electronically connected to a device microcontroller. The device microcontroller includes a first decoder and control means for the bar code reader, and a second decoder and control means for the RFID reader. Both of these decoder and control means are connected to a device communications, control and power unit. The device microcontroller is connected to a host computer via a computer bus, such as a USB. 
     In another embodiment, the multiple technology data reader includes a bar code reader and an RFID reader, each connected to a device microcontroller. The device microcontroller includes a bar code pre-processor and an RFID pre-processor, each of which are connected to a single decoding and control means. The decoding and control means is connected to a device communications, control and power unit. The device microcontroller is connected to a host computer via a USB. 
     Further variations, modifications and alternative embodiments are also described herein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a system block diagram of a multiple technology data reader, according to an embodiment of the present invention; 
     FIG. 2 is a functional block diagram of a multiple technology data reader, according to an embodiment of the present invention; 
     FIG. 3 is a block diagram illustrating the logical connections for a compound multiple technology data reader according to an embodiment of the present invention; 
     FIG. 4 is a block diagram illustrating the logical connections for a composite or complex multiple technology data reader according to another embodiment of the present invention; 
     FIGS. 5-10 illustrate six alternate circuit diagrams for different embodiments of the multiple technology data reader as described herein. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments will now be described with reference to the drawings. 
     FIG. 1 is a system block diagram of a preferred embodiment of a multiple technology data reader  10 . The multiple technology data reader  10  shown in FIG. 1 includes an optical code reader, such as a bar code reader  12 , a low frequency RFID reader  14   a , and/or a high frequency RFID reader  14   b . The bar code reader  12 , a low frequency RFID reader  14   a , and/or a high frequency RFID reader  14   b  are each connected to a device communications, control and power unit  16 . While it is convenient to combine communications, control and power functionality within the device communications, control and power unit  16 , such functionality can also be separated into different units, either in the FIG. 1 embodiment or the other embodiments described later herein. 
     The device communications, control and power unit  16  is preferably connected to a host device  30  over a USB  20 , which comprises a serial communications signal line  27  and a set of power signal lines  29 . The USB  20  supplies power from the host computer  30 , and establishes a two-way communication link between the multiple technology data reader  10  and the host computer  30 . As an alternative to the host computer  30  supplying power via the USB  20 , or in addition thereto, an independent power source (not shown) may be included within the multiple technology data reader  10 , either in the FIG. 1 embodiment or the other embodiments described later herein. 
     In operation, the device communications, control and power unit  16  receives data signals from the bar code reader  12  and the RFID readers  14   a  and  14   b , and provides power to each of these readers. The device communications, control and power unit  16  may also be used to activate the bar code reader  12  and the RFID readers  14   a  and  14   b  independently, simultaneously or concurrently. 
     FIG. 2 is a functional block diagram of a multiple technology data reader  10 , which can read a bar code  72  or an RFID tag  74 . The bar code  72  is read and detected by an optics means  42 , which sends the detected signal to an analog front end means  52 . The analog signal is then converted to a digital signal by a conversion to digital means  62 . The converted digital signal is decoded by a bar code decoder  28   a , and then sent to a host computer  30  via a USB  20 . 
     The RFID tag  74  is detected by an antenna  44 . The antenna transmits an electromagnetic signal  75  and detects a response signal  76  from the RFID tag  74 . The response signal  76  is sent to an RFID transmitter/receiver  64  through an impedance matching network  54 , which matches the impedance of the antenna  44  with the impedance of the RFID transmitter/receiver  64 . The response signal  76  is then decoded by an RFID decoder  28   b , and then sent to a host computer  30  via the USB  20 . 
     FIG. 3 is a block diagram illustrating a preferred configuration of logical connections for a multiple technology data reader  10   a  according to one embodiment utilizing a compound interface between the data reading components and the host device. In FIG. 3, a multiple technology data reader  10   a  includes an RFID reader  14 , connected to one port of an internal hub  18 , and a bar code reader  12 , connected to another port of hub  18 . The internal hub  18  is connected to a USB  20 , which supplies power from a host computer  30  and establishes a two-way communication link between the compound multiple technology data reader  10   a  and the host computer. The RFID reader  14  and bar code reader  12  are logically addressable over the USB  20  via the internal hub  18 . The multiple technology scanner  10   a  shown in FIG. 3 operates in a manner as described with regard to FIG.  1 . 
     FIG. 4 is a block diagram illustrating a preferred configuration of logical connections for a multiple technology data reader  10   b  according to another embodiment utilizing a composite or complex interface between the data reading components and the host device. In the FIG. 4 embodiment, the multiple technology data reader  10   b  includes an RFID reader  14 , and a bar code reader  12 , both connected to a USB  20 . The RFID reader  14  and bar code reader  12  are logically addressed without the use of an internal hub (such as used in the embodiment shown in FIG.  3 ). In the FIG. 4 embodiment, the USB  20  supplies power from a host computer  30  and establishes a two-way communication link between the composite multiple technology data reader  10   b  and the host computer. 
     In a variation of the FIG. 4 embodiment, the multiple technology data reader  10   b  uses a complex interface implementation that is based on human interface device (HID) report descriptors, and is specific to HID class USB devices (i.e. a keyboard, mouse, etc.). In all other respects, this variation operates in the same manner as the FIG. 4 embodiment as described above. 
     FIGS. 5-10 illustrate six alternative system architectures in accordance with a multiple technology data reader  10  such as shown in FIG.  1  and described herein. In a first embodiment, as shown in FIG. 5, the multiple technology data reader  100  includes a bar code reader subsystem  120 , and an RFID reader sub-system  140 , each serially connected to a device microcontroller  125 . The device microcontroller  125  includes a device interface  126   a  for the bar code reader subsystem, and a device interface  126   b  for the RFID reader subsystem, each of which is connected to a device communications, control and power unit  160 . The multiple technology data reader  100  also includes a trigger unit  170 , which sends and receives control signals and power, both to and from the device communications, control and power unit  160  on the device microcontroller  125 . The device microcontroller  125  is connected to a host computer  130  via USB  150 . 
     In the embodiment shown in FIG. 5, the reader device interfaces  126   a  has an input/output endpoint zero  110   a , which enables the host computer  130  to use a default control method to initialize and configure the reader device interface  126   a . In addition, the reader device interface  126   a  has an endpoint one  111 , which allows the host computer  130  to send data to the reader device interface  126   a , and an endpoint  112 , which allows the reader device interface  126   a  to send data to the host computer  130 . Furthermore, data can be sent in either direction between the reader device interface  126   a  and the barcode reader subsystem  120  via a serial communication line  105   a.    
     In a similar manner, reader device interface  126   b  has an input/output endpoint zero  110   b , which enables the host computer to use a default control method to initialize and configure the reader device interface  126   b . In addition, endpoint three  113  and endpoint four  114 , respectively allow the host computer to send data to the reader device interface  126   b , and the reader device interface  126   b  to send data to the host computer. Data can be sent in either direction between the reader device interface  126   b  and the RFID reader subsystem  140  via the serial communication line  105   b.    
     This first embodiment is an example of how the multiple technology data reader  300  may be readily implemented using off-the-shelf components. 
     In a second embodiment, as shown in FIG. 6, the multiple technology data reader  200  includes the optical and analog front end components of a bar code reader  220 , and the antenna and transmitter/receiver components of an RFID reader  240 , which are connected to a device microcontroller  225 . The device microcontroller  225  includes a decoder and control unit  228   a  for the bar code reader, and another decoder and control unit  228   b  for the RFID reader. The decoder and control units  228   a  and  228   b  are each connected to a device communications, control and power unit  260 . The multiple technology data reader  200  also includes a trigger unit  270 , which sends and receives control signals and power, both to and from the device communications, control and power unit  260  on the device microcontroller  225 . The device microcontroller  225  is connected to a host computer  230  via USB  250 . 
     In the embodiment shown in FIG. 6, the bar code decoder and control unit  228   a  has the same endpoints as the reader device interface  126   a  described in FIG.  5 . Likewise, the RFID decoder and control unit  228   b  has the same endpoints as the reader device interface  126   b  described in FIG.  5 . 
     In a third embodiment, as shown in FIG. 7, the multiple technology data reader  300  includes the optical and analog front end components of a bar code reader  320 , and the antenna and transmitter/receiver of an RFID reader  340 , which are connected to a device microcontroller  325 . The device microcontroller  325  includes a bar code pre-processor  322  and an RFID pre-processor  324 , both of which are connected to a common decoding and control unit  328 . The decoding and control unit  328  is connected to a device communications, control and power unit  360 . The multiple technology data reader  300  also includes a trigger unit  370 , which sends and receives control signals and power, both to and from the device communications, control and power unit  360  on the device microcontroller  325 . The device microcontroller  325  is connected to a host computer  330  via USB  350 . 
     In the embodiment shown in FIG. 7, the decoding and control unit  328  has an input/output endpoint zero  310 , which enables the host computer to use a default control method to initialize and configure the decoding and control unit  328 . In addition the decoding and control unit  328  has four additional endpoints, which enable data to be sent to and from the host computer  330 . 
     By integrating the bar code pre-processor  322 , the RFID pre-processor  324 , and the decoding and control unit  328  into the device microcontroller  325 , the manufacturing costs for the multiple technology data reader  300  may be reduced. Moreover, integration of these components enables optimal performance from the multiple technology data reader  300 . 
     In a fourth embodiment, as shown in FIG. 8, the multiple technology data reader  800  includes a bar code reader sub-system  820 , and an RFID reader sub-system  840 , each serially connected to a bus add-on card  825 . The bus add-on card  825  includes a device interface  826   a  for the bar code reader subsystem, and a device interface  826   b  for the RFID reader subsystem, each of which is connected to a device communications, control and power unit  860 . The multiple technology data reader  800  also includes a trigger unit  870 , which sends and receives control signals and power, both to and from the device communications, control and power unit  860  on the bus add-on card  825 . The bus add-on card  825  is connected to a host computer  830  via a computer bus  850 . The computer bus  850  may be any one of a variety of computer buses, including parallel or serial buses. 
     In the embodiment shown in FIG. 8, the reader device interfaces  826   a  has a controls input line  810   a , which enables the host computer  830  to send control commands to the reader device interface  826   a . In addition, the reader device interface  826   a  has a data output line  812 , which allows the reader device interface  826   a  to send data to the host computer  830 . Furthermore, data can be sent in either direction between the reader device interface  826   a  and the barcode reader subsystem  820  via a serial communication line  805   a.    
     In a similar manner, reader device interface  826   b  has a controls line  810   b , which enables the host computer  830  to send control commands to the reader device interface  826   b . In addition, the reader device interface  826   b  has a data line  812   b , which allows the reader device interface  826   b  to send data to the host computer  830 . Data can be sent in either direction between the reader device interface  126   b  and the RFID reader subsystem  840  via the serial communication line  805   b.    
     In a fifth embodiment, as shown in FIG. 9, the multiple technology data reader  900  includes the optical and analog front end components of a bar code reader  920 , and the antenna and transmitter/receiver components of an RFID reader  940 , which are connected to a device bus add-on card  925 . The bus add-on card  925  includes a decoder and control unit  928   a  for the bar code reader, and another decoder and control unit  928   b  for the RFID reader. The decoder and control units  928   a  and  928   b  are each connected to a device communications, control and power unit  960 . The multiple technology data reader  900  also includes a trigger unit  970 , which sends and receives control signals and power, both to and from the device communications, control and power unit  960  on the bus add-on card  925 . The bus add-on card  925  is connected to a host computer  930  via a computer bus  950 . The computer bus  950  may be any one of a variety of computer buses, including parallel or serial buses. 
     In the embodiment shown in FIG. 9, the bar code decoder and control unit  928   a  has the same input and output lines as the reader device interface  826   a  described in FIG.  8 . Likewise, the RFID decoder and control unit  228   b  has the same input and output lines as the reader device interface  826   b  described in FIG.  8 . 
     In a sixth embodiment, as shown in FIG. 10, the multiple technology data reader  1000  includes the optical and analog front end components of a bar code reader  1020 , and the antenna and transmitter/receiver of an RFID reader  1040 , which are connected to a bus add-on card  925 . The bus add-on card  925  includes a bar code pre-processor  1022  and an RFID pre-processor  1024 , both of which are connected to a common decoding and control unit  1028 . The decoding and control unit  1028  is connected to a device communications, control and power unit  1060 . The multiple technology data reader  1000  also includes a trigger unit  1070 , which sends and receives control signals and power, both to and from the device communications, control and power unit  1060  on the bus add-on card  925 . The bus add-on card  925  is connected to a host computer  1030  via a computer bus  1050 . The computer bus  1050  may be any one of a variety of computer buses, including parallel or serial buses. 
     In the embodiment shown in FIG. 10, the decoding and control unit  1028  has a controls input line  1010 , which enables the host computer to send control commands to the decoding and control unit  1028 . In addition the decoding and control unit  1028  has a data output line  1012 , which enables data to be sent from the decoding and control unit  1028  to the host computer  1030 . 
     In any of the embodiments depicted in FIGS. 5-7, the device communications, control and power unit  16  may be used to activate the bar code reader  12  and the RFID reader  14  independently, simultaneously or concurrently. In one embodiment, the device may be configured such that when a user pulls a trigger (not shown) on the outer body of the multiple technology data reader  10 , one of the following actions is initiated: (1) the bar code reader  12  alone is activated; (2) the RFID reader  14  alone is activated; or (3) both the bar code reader  12  and the RFID reader  14  are activated. 
     Alternatively, when a user pulls the trigger located on the outer body of the multiple technology data reader  10 , the bar code reader  12  is briefly activated to test for the presence of a bar code symbol. The presence of a bar code symbol may be indicated by the satisfaction of certain pre-set, user-defined criteria from among the following possible conditions: (a) presence of certain levels of reflected light (i.e. from laser, LED or ambient sources); or (b) presence of certain light modulation in response to printed symbols. If the test conditions are satisfied, then the bar code reader  12  remains activated until the trigger is released or a bar code is detected. Alternatively, if the test conditions are not satisfied, then the RFID reader  14  is activated for a pre-configured test or read operation. 
     In yet another alternative embodiment, the device may be configured such that when a user pulls the trigger located on the outer body of the multiple technology data reader  10 , the RFID reader  14  is briefly activated to test for the presence of an RFID tag based on the following set of pre-defined, user specified criteria: (a) return signals are detected that appear to be from decodable radio tags; or (b) packets of data are received which match certain pre-selected protocols. If the test conditions are satisfied, then the RFID reader  14  remains activated until the trigger is released or an RFID tag is detected. Alternatively, if the test conditions are not satisfied, then the bar code reader  12  is activated for a pre-configured test or read operation. 
     In any of the embodiments depicted in FIGS. 5-7, the user may specify which type of RFID tags should be read, and which should be ignored. For example, it is well known by those in the art that read/write tags can send an identification code, via a response signal, with multiple fields. The user may specify that the RFID reader  14  remain activated only if certain fields of the identification code sent by the RFID tag match user-defined criteria. 
     In addition, the user can also specify that the RFID reader  14  remain activated only if it appears that there is a single RFID tag in the read area. For instance, if there are multiple RFID tags in the read area, each RFID tag will send a response signal back to the RFID reader  14 . Generally, when this occurs there will be a collision between the multiple response signals. In this case, the user may specify that the RFID reader  14  be deactivated if such a collision is detected. 
     In the case where multiple RFID tags are detected by the RFID reader  14 , there may be an ambiguity as to which RFID tag is being read. To solve this problem, both an RFID tag and a bar code label may be placed on items to be identified. Then to avoid reading the wrong RFID tag, or having to physically separate the RFID tags, bar code reader operation may be automatically invoked instead when two or more RFID tags are detected. By activating the bar code reader  12  automatically, the user is able to obtain more precise and accurate information. 
     One advantage of this method of combining two automatic identification technologies into a single device is that the user is assured that a more accurate and reliable method of data acquisition is being employed for the specific task being performed. 
     While embodiments and applications of the present invention have been shown and described, it will be apparent to one skilled in the art that other modifications, alternatives and variations are possible without departing from the inventive concepts set forth herein. Therefore, the invention is intended to embrace all such modifications, alternatives and variations that fall within the scope and spirit of the appended claims.