Readers

The present invention relates to readers and reader devices. Examples include RFID readers.

RFID readers are commonly used to read information from transponders (which may be active or passive). The information in the transponder is typically a unique identifier which allows the reader to identify an item to which the transponder is attached, such as a box, crate or other packaging item. RFID readers allow items to be tracked through a supply chain, for example. Readers may be provided at fixed positions, for example at loading bays.

In other situations, the transponder may be attached to an individual item, such as a manufactured article or an item of stock in a shop. This allows stock levels to be checked easily, using a handheld reader.

Various RFID systems have been proposed for use in low frequency, high frequency and ultra high frequency bands. Various protocols for signal transmission have also been proposed.

Examples of the present invention provide apparatus comprising:

a reader circuit operable to read information from an article by communication through a radio antenna;

a set of antennas;

a mounting arrangement to replaceably receive an antenna chosen from the set of available antennas, to connect the chosen antenna with the reader circuit;

identification means operable to identify at least one parameter of an antenna received by the mounting arrangement; and

control means operable to control the operation of the reader circuit in dependence on the parameter identified by the identification means..

The control means may be operable to enable and disable the reader circuit in dependence on the recorded parameter. The control means may be operable to use the recorded parameter to determine if the current location of the apparatus is appropriate for the use of the chosen antenna and/or jf the reader circuit is configured for use with the chosen antenna.

Alternatively, the control means may be operable to modify the operation of the reader circuit in dependence on the recorded parameter. The control means may be operable to modify at least one of the power output, frequency of operation and signal protocol in use. The operation of the control means may be modified to optimise the performance of the reader circuit in combination with the chosen antenna. The operation of the control means may be modified to cause the output of the reader circuit in combination with the chosen antenna to meet regulatory requirements. The operation of the control means may be modified in accordance with the nature of the intended task.

The identification means may include identification means within at least one antenna. The identification means within the or each antenna may record at least one parameter of the corresponding antenna. The control means may be operable to identify a parameter by reading the parameter recorded within the corresponding antenna. The control means may be operable to control operation in dependence on the parameter recorded by the identification means within the corresponding antenna.

The identification means within each antenna may comprise a memory, the mounting arrangement comprising a connection arrangement operable to allow the control means to read the contents of the memory.

Alternatively, the identification means may comprise a plurality of terminal connections, and state means operable to set the state of each terminal connection to indicate the parameter, the mounting arrangement comprising cooperating terminal connections by means of which the control means may determine the electrical state of each terminal connection, thereby determining the parameter. The state means may comprise switches to provide binary states for the terminal connections.

In a further alternative, the identification means may comprise a detection arrangement operable to detect the presence of an antenna at the mounting arrangement, the control means being operable in response to the detection of an antenna to vary an operating parameter through a range, and to detect the response of the antenna thereto. The varied parameter may be the operating frequency.

The identified parameter may be a performance parameter or may be an identifier unique to the type of antenna, or may be an identifier unique to the individual antenna.

The reader circuit may be operable as an RFID reader.

The apparatus may comprise a handheld unit to which a chosen antenna is replaceably mounted, for use. The control means may be contained within the handheld unit. Alternatively, the control means may be located, at least in part, in a base station with which the handheld unit is in wireless communication.

The handheld unit may comprise a battery compartment, a module having a power source and a connection arrangement for receipt in the battery compartment to connect the power source to power the unit, and the connector arrangement further comprising the antenna mounting arrangement. The power source may be located outside the battery compartment.

In another aspect, examples of the invention provide a hand-held battery- powered RFID reader, comprising:

a battery compartment for a removable battery;

a module having a power source and a connector arrangement for receipt in the battery compartment to connect the power source to power the unit;

the connector arrangement further comprising a mounting arrangement for releasably mounting a radio antenna for use by the RFID reader.

Example embodiments of the present invention will now -be described in more detail, with reference to the accompanying drawings, in which:

Fig. 1 is a simplified schematic diagram of a first embodiment;

Figs. 2, 3 and 4 are schematic diagrams of identification arrangements for use in the system, of Fig. 1 ;

Fig. 5 is a perspective view of an embodiment, without an antenna attached; and

Fig. 6 is an elevation of an embodiment, indicating two possible antenna configurations.

Turning to figure 1, there is shown apparatus 10. In the examples to be described, the apparatus 10 is a hand-held RFID reader.

The reader 10 comprises a reader circuit 12 operable to read information from an article 14 in the form of a transponder of conventional type for use in an RFID system. The transponder 14 may be active or passive. The circuit 12 reads information from the article 14 by communication through a radio antenna 16.

The antenna 16 is chosen from a set of available antennas 16a, 16b etc. A mounting arrangement indicated generally at 18 is provided to replaceably receive the chosen antenna 16, to connect the chosen antenna 16 with the reader circuit 12.

Identification means 20 (to be described in more detail below) are provided to identify at least one parameter of the corresponding antenna 16. In this example, the identification means 20 are within each antenna 16. Other examples are described below.

The antennas 16, 16a, 16b may have a variety of designs and performance characteristics, such as resonant frequency, power capability, directional characteristics, gain etc.

Control means 22 are provided for the apparatus 10, to control the operation of the reader circuit 12 in dependence on the parameter recorded by the identification means 20 of an antenna 16 received by the mounting arrangement 18.

The control means 22 may conveniently be in the form of a microprocessor, microcontroller or other software driven device or circuit, for which software may be stored at 24. When the apparatus 10 is in use, the controller 22 executes the software 24 to perform the operations which will be described below, and others.

Figure 2 illustrates one example of identification means 20. In this example, the antenna 16 incorporates a read-only memory 26 to which the controller 22 has access when the antenna 16 is fitted in the mounting arrangement 18. This allows the controller 22 to read the contents of the memory 26, thereby recovering the parameter recorded in the memory 26. The parameter may be a performance parameter or an identifier unique to the type of antenna or to the individual antenna. The purpose of the recorded parameter will be described in more detail below.

Figure 3 illustrates an alternative example. In this example, the interface provided by the mounting arrangement 18 between the controller 22 and the antenna 16 includes a plurality of terminal connections 28 (there being four in this example). Within the antenna 16, each terminal connector 28 has an associated switch 30 through which the corresponding terminal connection 28 can be connected to ground potential 32 or left to float. The switches 30 may be in any convenient form, such as mechanical, semiconductor or software switches. The purpose of the switches 30 is to set the state of each terminal connection 28. The states of the terminal connections 28 thereby provide a four-bit binary indication of the recorded parameter. The binary indication can be read by the controller 22 by determining the state of each of the terminal connections 28 when the antenna 16 is mounted by the arrangement 18. Alternatively, the four states can be interpreted as four flags representing the state of four parameters of the antenna 16.

In another example, illustrated simply in figure 1, the identification means may include a switch 20a and an identification means 20 in the form of a barcode or other machine-readable information. In this example, the switch 20a is used by the controller 22 to detect the presence of an antenna 16 at the mounting arrangement 18. Once the switch 20a has indicated to the controller 22 that an antenna 16 has been removed, the controller 22 may disable the reader 12 until the barcode (or other machine-readable information) of antenna has been read

(for example by operation of a laser barcode reader circuit 36, to be described more fully below). The barcode includes encoded information corresponding to a parameter of the antenna. Once the barcode has been read, and the antenna has been connected, which will be detected by the switch 20a, the controller 22 re enables the reader 12, to operate in a manner dependent on the information identified by means of the barcode.

Alternatively, provision may be made for reading the barcode or other machine readable information while the antenna is connected. For example photodiodes could be used to read graphic information.

In a further example which makes use of the switch 20a, the controller 22 may implement a form of measurement in order to identify at least one parameter of the antenna received in the mounting arrangement 18. In this example, the presence of an antenna 16 in the mounting arrangement 18 is indicated to the controller 22 by the state of the switch 20a. When a new antenna is installed, the controller 22 operates the reader 12 to use the antenna 16 by varying an operating parameter through a range, and to detect the response of the antenna. For example, if the reader 12 is capable of operating across a wide range of frequencies, but any particular antenna is primarily suitable only for a subset of the range of frequencies (perhaps for regulatory reasons, for instance), the reader 12 can sweep the operating frequency across the entire operating frequency range available to the reader 12, preferably at a low power level. The reader 12 measures the amount of power reflected back from the antenna 16, due to the mismatch between the instantaneous operating frequency and the antenna characteristics. The reader 12 and controller 22 can then find the resonant frequency or frequencies of the particular antenna. In this manner, the parameter of the operating frequency of the antenna is therefore identified. This form of identification can be used in relation to parameters for which a range of operating values are available for the reader 12, and for which a measurable change in antenna response is available.

In a further example (Fig. 4), the identification means 20 may be a device of the type for which the antenna 16c is designed, embedded within the antenna 16c.

For example, an RFID tag may be embedded. In this example, the antenna may be used, when first connected, to read the tag embedded within itself. This recovers information from the tag, identifying the antenna, as discussed above, and also confirms that the antenna and reader are functioning correctly together.

Responses from the embedded tag can subsequently be ignored or filtered out.

Periodic checks of this nature allow correct operation to be confirmed and reported, if required.

In each of these examples, after an antenna 16 has been mounted on the arrangement 18, and before the reader 12 is used to read information from the article 14, the controller 22 identifies a parameter by using the identification means 20. The identified parameter may be a performance parameter. For example, the parameter may be the frequency or frequency band for which the antenna 16 is optimised. The parameter may indicate whether the antenna 16 is optimised for near field or far field use, or may indicate the maximum permissible power for the antenna 16.

Alternatively, the identified parameter may be an identifier unique to the type of antenna. Thus, by identifying the class of antenna to which the connected antenna belongs, the controller 22 is able to identify performance parameters such as those mentioned above, for example by consulting a look up table available to the controller 22. In a further alternative, the identified parameter may be an identifier unique to the individual antenna. Again, an appropriate look up table will allow the controller 22 to determine performance parameters of the selected antenna 16.

Other parameters may be considered by the controller 22, before reading begins. For example, the controller 22 may consider the current location of the apparatus

10. Location may be determined by a function 34. This may be a positioning technology such as a GPS system. Alternatively, the function 34 may be provided by a Bluetooth or other wireless connection allowing communication with a base station 35 in order to identify the location of the apparatus 10. Other wireless protocols, such as 802.11 may be used as alternatives to a Bluetooth link. In a further alternative, the function 34 may read locally available information, such as a barcode, which indicates the current location of the device (in a territory or within areas of premises, for example). The reading function may be provided by the circuit 36, described below.

The location of the apparatus 10 may be significant in various ways. The location may affect the regulatory requirements, which typically vary from country to country or from region to region and define permissible frequencies, operating power or other requirements or limitations. Alternatively, the location may be determined more precisely in order to ensure that operating parameters used in some locations are not used in others. For example, in retail premises, higher power might be permitted in store rooms than on the shop floor, with members of the public present. Other operating parameters may be affected by location, particularly by regulatory requirements, such as the permitted modulation techniques used for the RFID signals, carrier frequency hopping sequences and rates, channel spacings, duty cycles etc.

The controller 22 may also consider the nature of the task instructed of the reader 10, to ensure that the selected antenna 16 is appropriate for the task. For example, a task may require a particular frequency band to be used, in which case the controller 22 may consider if the selected antenna 16 is appropriate for operation in that frequency band. In another example, a particular task may determine the required gain of the antenna, perhaps depending on the range or area to be covered in the task. In this example, the controller 22 may consider if the selected antenna 16 has the required gain.

Having identified the parameter from the chosen antenna 16, the controller 22, in one example, chooses to enable or disable the reader circuit 12 in dependence on the identified parameter. For example, if the chosen antenna 16 is inappropriate for the reader circuit 12 (that is, the antenna 16 and the reader circuit 12 are incompatible for some reason, such as operating frequency) the reader circuit 12 is disabled. Alternatively, the chosen antenna 16 may be inappropriate for use at that location, or for the intended task. Thus, the controller 22 considers at least the parameters identified from the chosen antenna 16, and any other relevant parameters, such as location, before deciding to enable or disable the circuit 12.

In another example, the controller 22 may use the identified parameter to modify the operation of the reader circuit 12. For example, the controller 22 may instruct the circuit 12 to limit the output power to be within the maximum permissible power for the chosen antenna 16. Alternatively, the controller 22 may instruct the circuit 12 to use an appropriate frequency for which the chosen antenna 16 has been optimised. The appropriate signal protocol to be used may also be instructed by the controller 22 to the circuit 12. It is envisaged that the controller 22 can modify the operation of the reader circuit 12 to optimise the performance of the reader circuit 12 in combination with the chosen antenna 16, or to prevent operation in the event that the reader circuit 12 and chosen antenna 16 are incompatible. Instructions from the controller 22 to the circuit 12 are also used to ensure that the output of the apparatus 10 conforms with regulatory requirements. Again, the instructions from the controller 22 may be based only on the parameter identified from the chosen antenna, or from this in conjunction with other relevant parameters, such as location.

If the reader circuit 12 is disabled as a result of the identified parameter, an error message may be provided to the operator. The message may indicate an appropriate (or more appropriate) alternative antenna.

In addition to the features described above, the apparatus 10 also includes a laser circuit 36 for use in reading barcodes (which may be one-dimensional or two-dimensional).

A power supply 38, which may be in the form of the replaceable battery, is provided to power the various components of the apparatus 10.

The remaining drawings illustrate an example of apparatus 10 contained within a housing 40. The housing 40 has formations at 42 and a strap 44 which together allow the housing 40 to be secured to the fingers of a user. Control buttons (not shown) on the upper surface 46 of the housing 40 allow the thumb of the user to be used to control the apparatus 10.

A window 48 is provided for the laser circuit 36 to project a laser beam for reading a barcode. A battery compartment 50 is provided and is illustrated in figure 5 with the compartment cover removed, to reveal connection features 52. A module 54 includes a power source generally at 56 and, in this example, in the form of a power pack of batteries or cells. A connector arrangement for connection with the handheld unit 40 is provided in the form of walls 58 for receiving the lower extremity of the housing 40, and a tongue 60 received in the battery compartment 50. The tongue 60 provides appropriate connections to connect a power source 56 to the unit 40, to power the unit 40. In addition, the tongue 60 allows a chosen antenna 16 to be mounted to the housing 40. In particular, the tongue 60 leaves the connection features 52 exposed, allowing these to be used by the antenna 16 in place of the battery compartment cover, which is not used. Additional mechanical connections may be provided by the tongue 60, for engaging the antenna 16. In addition, electrical connections are preferably provided on the tongue 60, to provide electrical connection between the chosen antenna 16 and the controller 22 within the housing 40.

Figure 6 illustrates two examples of different antennas selected for use. In figure 5, solid lines are used to indicate a first antenna 16c which, as can be seen, is relatively long and thin and generally aligned with the housing 40, extending below the lower extremity of the housing 40 and in front of the power source 56. It can be seen from figure 4 that the power source 56 is positioned to the rear of the tongue 60, to allow the antenna 16c to extend down in this manner. In an alternative, an antenna 16d is attached, illustrated in broken lines. The antenna 16d is much wider than the antenna 16c, extending to a significant extent to either side of the housing 40, but does not extend so far down the housing 40. In particular, the power source 56 remains visible below the housing 40. It is to be understood that the two shapes described for the antennas 16c and 16d are solely by way of example and that many other antenna shapes and designs could be used, according to the application envisaged for the apparatus 10.

Many variations modifications can be made to the apparatus described above. In particular, it is envisaged that the examples can readily be adapted for use with any current or future RFID protocols, or other situations for which a handheld reader is required to use radio techniques to provide a wireless link. The control processes have been described as taking place solely within the handheld device 10, by operation of the controller 22. However, the provision of a Bluetooth or other wireless link 34, and a base station 35, allows control to be shared with the base station 35, or to be executed exclusively at the base station 35. The base station 35 may be a PC or other computer, and may therefore have greater processing power than the controller 22.

In each of the examples above, the description may have suggested that every antenna will have only a single resonant or working frequency, or frequency band. However, many antenna designs have multiple ^' resonances, working frequencies or bands. In those cases, the required decision may take into account each of the available resonances and working frequencies, assess if any

is appropriate, and ensure that operation makes use of that resonance or frequency.

Replaceable antennas can be changed when damaged or faulty.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.