Patent Application
20060103532
Not Applicable
Not Applicable
1. Field of Invention
This invention pertains to electromagnetic identification of tagging of merchandise employing radio frequencies.
More particularly, this invention pertains to a method and apparatus for improving the transmissions of electromagnetic (particularly radio frequency) radiation between an RFID reader and a remote product having an RFID tag associated therewith.
2. Description of the Related Art
Current practices in inventory management are increasingly employing Radio Frequency Identification (RFID) tags to monitor the progress of merchandise as the individual items or packages move through the supply chain from the manufacturer to the wholesaler to the retailer shelves and/or even to the end user. In this monitoring system, each item or package of merchandise is provided with an RFID tag which is capable of electronically storing various information such as the identity, quantity, etc. of the item and/or its contents, origination source, and substantial other information deemed to be useful in monitoring the movement of the item through the channels of commerce and/or ultimate disposition of the item.
Radio frequencies (RF) are subject to distortion, reflection, weakening, and other adverse effects by such materials as liquids and/or metals, and other environmental effects such as the distance of travel of the RF signal and the presence or absence of RF-blocking or distortion materials between the source of the RF and the receiver thereof (RFID reader, for example).
In commerce, it is common to stack products or cartons containing products on pallets for storage or shipping, for example. If the carton is tagged with an RFID tag, by scanning the individual carton or a plurality of cartons on a single pallet with an RFID reader, the identity and number of items contained within the carton or the identity of the cartons in the stack are ascertainable.
However, the known limitations on this activity by reason of the presence in the field of the RF of certain materials which hinder the transmission of the signal, for example, strongly adversely affect the accuracy of the detection and reading of RFID tags associated with individual items of merchandise or individual items or clusters of individual items with RFID tags on them. When packages or containers containing liquids or metals are clustered in a typical shipping pallet configuration or on a retail shelf, then the RFID reader may not recognize all of the RFID tags. This will result in a miscount, essentially destroying the value of the inventory controls. This problem of “invisible” RFID tags is particularly troublesome where the individual packages of product are oriented such that the RFID tag is not “visible” to the RFID reader. This situation may occur due to the orientation of cases of product stacked on a pallet, and especially may occur when individual packages of products are disposed on a retail display shelf in side-by-side relationship. That is, on retail display shelves, space is at a premium and retailers tend to arrange packages of like products in abutting relationship to one another, an action which frequently hides the RFID tag from an RFID reader. This problem is compounded when the product container in the package, or the package itself, includes a liquid or metal material. Cigarette packages which may include metallized foil is one example.
The current EPC standard for RFIDs and their readers are 13.56 MHz and 915 MHz. Both of these frequencies are impacted by the presence of liquids and metals. The inability to read all the RFID tags on packages on a shipping pallet significantly reduces the business value proposition or cost justification for implementing RFID technology in the supply chain. For example, if a shpper must break down a pallet containing 80-120 shipping cases in order to read the RFID tag on each case, then there is no value proposition. Current RFID reader configurations, i.e. dock door portals, stationary readers and hand held readers, cannot read all the RFID tags in a pallet configuration when the products or packaging contain liquids and/or metals. Typically such reader configurations can read those tags that are found on the outer surfaces of the pallet configuration and some of the tags that have a clear read pathway, i.e., no liquids or metals between the reader and the RFID tag.
Compounding the problem of accessibility to the cartons/packages by RF radiation is the cost of the tags themselves. To make a tag which has greater “broadcasting strength” is materially more expensive than making a tag which has a limited broadcast strength. Thus, increasing the broadcasting strength of the chip in the RFID, to date, has not been an acceptable option.
In accordance with one aspect of the present invention, the present inventor provides an inhanced pathway from a remote RFID reader to a plurality of target tags associated with single or multiple packages, cartons or cases of packaged or unpackaged merchandise, in the form of a supplemental antenna interposed between a location operatively adjacent one or more of individual cases or packages of products which are disposed in stacked or palletized configuration, for example. This supplemental antenna provides for substantially uninterrupted transmission of RFID signals between an RFID reader and an RFID tag irrespective of the presence of RFID-transmission barriers associated with closely stocked or aggregated RFID tag-bearing cases, cartons or other packaging of products. It further alleviates RF transmission problems due to the process of water, other liquids and/or metal which may be contained in the clustered packages or otherwise interposed between the RFID tag and the reader. In a preferred embodiment, the present invention includes a slip sheet having a plurality of spaced apart supplemental antennas associated therewith, each supplemental antennae being adapted to transmit RF signals to and from a remote RFID reader (having an antennae associated therewith) and a plurality of RFID tags associated with groupings of merchandise, for example.
In
In
In the embodiment depicted in
In the embodiment of the present invention depicted in
Each slip sheet 56, for example, itself may be formed from any material which does not materially interfere with the transmission of RF signals and which provides the normal function of a slip sheet. Preferably the slip sheet material is transparent to RF signals, such as is corrugated paperboard. By this means, RF signals may be transmitted bidirectionally between a reader 18″ and its antenna 19″ and each of the supplemental antennas 52 and also bidirectionally between the supplemental antennas and those cases in the row above the slip sheet and those cases in the row below the slip sheet. Paper sheet material having a basis weight of between about 40 and about 200 per 3000 ft2 is commonly employed as slip sheet material. Desirably, the slip sheet material contributes minimally to the cost of the completed slip sheet in that slip sheets commonly are not recycled as slip sheets. However, depending upon the durability of the slip sheet material, if desired, the antennae-bearing slip sheets may be recycled.
Fixation of the antennas 52 to the top surface 54 of the slip sheet 56 may be by any conventional means for affixing antennas to planar materials. In addition to glue-type affixation of the antennas to the slip sheet, the antennae may be printed on or embossed into the slip sheet, embedded in the slip sheet, plasticized or other wise fixed in their spaced apart locations over the top surface of the slip sheet. Through choice of the size and geometry of the multiple antennas 52, the present inventors may selectively provide suitable antennas for any of a large variety of shapes and sizes of cases, cartons, etc. on the pallet.
Whereas the slip sheet depicted in
In one embodiment of an antenna-bearing slip sheet 56 of the present invention, as shown in
In a further embodiment of the present invention, as depicted in
In accordance with one aspect of the present invention, the ability to create electromagnetic pathways through a palletized grouping of RFID-tagged products opens up the opportunity of eliminating those current limitations of the 915 MHz frequency togs which are associated with the physics of systems currently in use.
Further, as desired or used, the slip sheet may be seamed or perforated to provide visibility of the electromagnetic pathway to the readers.
Whereas the present invention has been described employing specific examples, it is intended that the invention be limited only as set forth in the claims appended hereto. Moreover, whereas the permanent slip sheets may not provide for identification of 100% of the RFID tags in an aggregation of tagged products, the present invention has repeatedly demonstrated identification of ninety-plus percent of palletized tagged products which have liquid or metal materials associated therewith.
