Abstract:
A radio frequency identification (RFID) device includes a communication arrangement which receives data from and/or sending data to a data processing unit via a wireless communication. In addition, the RFID device includes a solar cell/panel which provides power for the RFID device.

Description:
PRIORITY CLAIM  
       [0001]     Priority is claimed to U.S. patent application Ser. No. 10/128,730 Apr. 22, 2002 2004 “Power Source System for RF Location/Identification Tags”. The entire disclosure of this prior application is considered as being part of the disclosure of the accompanying application and is hereby expressly incorporated by reference herein. 
     
    
     BACKGROUND INFORMATION  
       [0002]     Radio Frequency (“RF”) device, such as RF identification device, has become an important implementation of an Automatic Identification technique. The object of any RF system is to carry data suitable transponders, generally known as tags, and to retrieve data, by machine-readable means, at a desired time and place to satisfy particular application needs.  
         [0003]     Data within a tag may provide identification for an item in manufacture, goods in transit, a location, the identity of a vehicle, an animal, individual, etc. Additional data may be provided for supporting applications through item specific information or instructions immediately available on reading the tag. For example, the color of paint for a car body entering a paint spray area on the production line, the set-up instructions for a flexible manufacturing cell or the manifest to accompany a shipment of goods. In other cases, information may be obtained, indirectly, merely by observing the characteristics of the tags&#39; transmissions—signal strength, multipath delay profile, or time of arrival, for example. RF technologies vary widely in frequency, packaging, performance, and cost.  
         [0004]      FIG. 1  shows a conventional RF system  1  which includes an RF tag  10  (e.g., an RFID tag) and an RF arrangement  2  for reading or interrogating the tag  10 . The arrangement  2  communicates with a data processing unit  3  to exchange data with the tag  10 . The system  1  may also include a facility (not shown) for entering or programming data into the tag  10 , if this is not undertaken at source by the manufacturer of the tag  10 .  
         [0005]     Communications of data between the tag  10  and the arrangement  2  may be performed using a wireless communication technology. Two methods distinguish and categorize RF systems: a first method is based upon close proximity electromagnetic or inductive coupling; and a second method is based upon propagating electromagnetic waves. Coupling is via ‘antenna’ structures  4 ,  12  forming an integral feature in both the tag  10  and the arrangement  2 . While the term “antenna” is generally considered more appropriate for propagating systems, it is also loosely applied to inductive systems.  
         [0006]     Transmitting data is subject to the influences of the media or channels through which the data has to pass, including the air interface. Noise, interference and distortion are the sources of data corruption that arise in practical communication channels that must be guarded against in seeking to achieve error free data recovery. The nature of the data communication processes requires attention to the form in which the data is communicated. Structuring the bit stream to accommodate these needs is often referred to as channel encoding and, although transparent to the user of an RF system, the coding scheme applied appears in system specifications. Various encoding schemes can be distinguished, each exhibiting different performance features.  
         [0007]     To transfer data efficiently via the air interface or space that separates the two communicating components requires the data to be superimposed upon a rhythmically varying (sinusoidal) field or carrier wave. This process of superimposition is referred to as modulation, and various schemes are available for this purposes, each having particular attributes that favor its use.  
         [0008]     RF tags may be either active or passive. A passive tag has a limited utilization (e.g., a theft prevention device in a store). On the other hand, an active tag may provide a plurality of data which can be modified.  FIG. 1  shows a conventional active tag  10  including a transmitter or transceiver arrangement  12  which can send to the arrangement  2  data identifying information, current status, current location, or other useful data. In addition, the tag  10  has a battery and may also include a microprocessor  14  and a memory  18 . In some cases, the data stored on the memory  18  may be rewritten and/or modified. However, a disadvantage of the active tag  10  is that the RF transmissions require a significant amount of power. This power requirement results in the additional cost of self-contained battery and the limited operational life of the battery leads to the expense of frequently replacing the batteries and/or the tags themselves.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention relates to a radio frequency (“RF”) device (e.g., an RF tag) which includes a communication arrangement and an input arrangement. The communication arrangement sends and/or receives data. The RF device obtains power from the target device through the input arrangement. Thus, the RF device according to the present invention is provided with a viable alternative to a full reliance on a stand alone battery. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0010]      FIG. 1  shows a conventional RF system;  
         [0011]      FIG. 2  shows an exemplary embodiment of an active RF tag according to the present invention;  
         [0012]      FIG. 3  shows another exemplary embodiment of an active RF tag according to the present invention;  
         [0013]      FIG. 4  shows yet another exemplary embodiment of an active RF tag according to the present invention; and  
         [0014]      FIG. 5  shows a further exemplary embodiment of an active RF tag according to the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0015]     According to present invention, a radio frequency (“RF”) device, such as an active RF tag is adapted to obtain power from a viable alternative to a full reliance on a stand alone battery. The active RF tag may be able to receive and transmit RF signals using a plurality of wireless local area network (“WLAN”) communication standards (e.g., IEEE 802.1x). The power may be obtained from a variety of sources, for example, direct, in-line, inductive and/or solar power sources which are described in detail below.  
         [0016]      FIG. 2  shows an exemplary embodiment of a device  22  including a RF tag  10   a according to the present invention. The device  22  has a serial interface connector  20  which may be used to obtain or provide data and power for RF tag  10   a . The RF tag  10   a , situated inside the device  22 , obtains its power source feeding the power in connection of the serial interfac  20 . Those skilled in the art would understand that power may be obtained from any type of interface connector which transmits power, such as, Universal Serial Bus (“USB”), a “firewire” (i.e., IEEE 1394), parallel, microphone, etc.  
         [0017]     Examples of products which enable such tags are laptops, personal digital assistance (PDAs), medical equipment, etc. These devices generally have the type of connections described above. Thus, a RF device such as exemplary device  22  may acquire power from the target device (e.g., laptop , PDA) via the appropriate connection. In this manner, the power supply of the target device does not need to be disturbed. Those of skill in the art will understand that some minor modifications of the target device software may be needed to activate the port or connection where the RF tag  10   a  is connected.  
         [0018]      FIG. 3  shows another exemplary embodiment of a device  24  including a RF tag  10   b  according to the present invention. The device  24  has a first connection  28  which is connected to a power source  37  and a second connection  30  which is connected to a target device  38  for which the RF tag  10   b  is designed. Thus, the device  24 , which may be in the form of a short power cord, is inserted between the power source  37  and the target device  38 . The RF tag  10   b  obtains its power from the power that flows between the power source  37  and the target device  38  through the device  24 . The device  24  does not interrupt the power flow to the target device  38 . In addition, the device  24  may use the third party ground plug  26  as an extension antenna for the RF tag  10   b  or for transmission/reception of data. The device  24  may be particularly useful for target devices which have power sources that are separate from the device itself, e.g., any device which is plugged into a wall outlet.  
         [0019]      FIG. 4  shows a further exemplary embodiment according to the present invention of a device  32  including a RF tag  10   c  and an inductive clamp  40 . The tag  10   c utilizes an inductive coupling as its power source rather being directly attached to a power supply or “in-line”. The inductive coupling may be used so that the available magnetic fields emanating from a tracked device&#39;s current supply may be converted to power for the tag  10   c . The device  32  may be hooked around a power cable by the inductive clamp  40  which provides power to the tag  10   c . The device  32  may be particularly useful in applications where it is impractical to attach additional wires to the target device. Another manner for obtaining power via inductive forces is though the use of a current transformer (CT).  
         [0020]      FIG. 5  shows yet another exemplary embodiment according to the present invention of a device  42  which includes a RF tag  10   d  and a solar power battery  36 . In this embodiment, the tag  10   d  utilizes the power generated by the solar power battery  36 , thus, allowing the tag  10   d  to function without a conventional battery. Those of skill in the art will understand that the device  42  may be especially useful in those cases where the application of the device  42  includes prolonged exposure to the light, e.g., an RF tag in a car for toll road use, an RF tag on outdoor equipment, etc.  
         [0021]     Those skilled in the art would understand the above described alternative power sources for the RF tags may be utilized in addition to a conventional battery. For example, the tag  10   c  may utilize the power from both a battery and the inductive power generated from the clamp  40 . The indicative power may directly serve the tag  10   c  or recharge the battery.  
         [0022]     The devices according to the present invention may be utilized in various industries. For example, such devices may be utilized in a health care industry. The RF tags may be attached to a number of medical devices which move around a hospital. Having such tags allows the hospital to manage and track its equipment. At the same time, having such alternative power sources, allows the hospital to significantly reduces the maintenance cost associated with such tags because one of the above described tags may be utilized for any piece of hospital&#39;s equipment.  
         [0023]     Another example of utilization of the present invention is in a retail industry. For instance, devices with the above described RF tags may be used as “proximity sensors”. A particular supermarket may have a location tracking system which allows it to determine the location of shoppers. Thus, when a shopper approaches a particular area, e.g., a frozen food section, a personalized coupon on frozen dinners is offered to that shopper to entice him/her to make a purchase. Such may be achieve by placing RF tags as beacons in every section of the supermarket. The shopper may have a tag which reflects the beacon information (e.g., a preferred customer card) or RF equipment to receive the beacon information (e.g., PDA). The cost and time for maintenance of a such system may be reduced when these beacons/proximity sensors use the alternative power source as described above.  
         [0024]     Thus, the present invention provides an alternative to stand-alone batteries. The alternatives include the reduction of the load on the tag&#39;s internal supplies, the discarding of internal sources entirely, a method of recharging the tag&#39;s batteries during normal, everyday usage, etc.  
         [0025]     There are many modifications to the present invention which will be apparent to those skilled in the art without departing from the teaching of the present invention. The embodiments disclosed herein are for illustrative purposes only and are not intended to describe the bounds of the present invention which is to be limited only by the scope of the claims appended hereto.