MOVABLE RFID READING DEVICE
Field of the Invention
[0001] The present invention generally relates to Radio Frequency Identification
(RFID) technology for inventory systems, and more particularly to a movable RFID reading device for interrogating RFID tagged articles.
Background of the Invention
[0002] Radio Frequency Identification (RFID) technology is increasingly used in inventory management systems to track and control goods or articles. Generally, a RFID tag is attached to an article and it contains the information associated with the article. A RFID reader or scanner is then used to interrogate or scan the tags to capture the stored information of the tag attached to the article.
[0003] Commercial and public environments such as warehouses and libraries are known to implement RFID systems to maintain and control their large inventories of articles or books. However, there are certain limitations in those RFID systems. For example, the RFID systems could only capture the movement of inventoried articles at stations where RFID readers are installed, such as gantry points and check-in/check-out points. Thereafter, the management of the articles depends on the warehouse staff or librarians. In one instance, a particular article within a warehouse or library may be misplaced on the shelf and needs to be located. In another instance, the article must be located for inventory purposes. Typically, warehouse staff and librarians use a handheld portable RFID reader to manually locate the desired article.
[0004] WO 99/05660 discloses a library inventory control system where librarians use portable RFID scanners to perform inventory and verify that articles are placed on the proper shelf. These RFID scanners are coupled to a portable computer that stores the data collected by the RFID scanners. The drawbacks of this inventory control system are that the portable RFID scanner coupled to the computer is costly and cumbersome for the librarians to operate with. Furthermore, the manual inventorying process by librarians is laborious and inefficient. Also, additional manpower is required to perform a massive inventorying of the articles.
[0005] In the present market, some inventory management systems implement
Smart Shelf solutions to overcome the drawbacks of manual inventorying process. Basically, the Smart Shelf has integrated antennas in every shelf that interrogates the RFID tagged articles places on the shelf. These integrated antennas are coupled to RFID readers to transmit the data associated from the tags to the RFID readers. Thus, the Smart Shelf performs automatic inventory of the articles and registers any misplaced articles. Although the Smart Shelf addresses the issue of automatic inventorying of articles, it does have certain drawbacks. For example, retrofitting the antennas and readers in each and every shelf is costly and cumbersome. Furthermore, the amount of RF signal generated by the antennas also creates problems such as magnetic field coupling between neighboring antennas, and "blind-spot" reading due to the polarization of tags. It is also difficult to customize the size of antennas to operate properly in different sizes of the shelf. Also, the maintenance of the enormous amount of RFID equipment in the Smart Shelf is costly. [0006] Therefore, there is an imperative need to have a RFID system that can provide efficient reading of RFID tagged articles and overcome the above-discussed problems. This invention satisfies this need by disclosing RFID system with a movable RFID reader. Other advantages of this invention will be apparent with reference to the detailed description.
Summary of the Invention
[0007] The present invention provides RFID system that provides efficient tracking and controlling of RFID tagged articles arranged in a bookshelf, rack or the like. [0008] Accordingly, in one aspect, the present invention provides a system for tracking a plurality of articles arranged sequentially, where each of the plurality of articles is attached with a Radio Frequency Identification (RFID) tag that stores the data associated with the article, the system comprising: a RFID reading device configured to interrogate the RFID tag on each of the plurality of articles; and a conveyor means coupled to the RFID reading device, wherein the conveyor means is configured for moving the RFID reading device to each of the plurality of articles, thereby allowing the RFID reading device to interrogate the RFID tag on each of the plurality of articles. [0009] In another aspect, the present invention provides a method for tracking a plurality of articles arranged sequentially, where each of the plurality of articles is attached
with a Radio Frequency Identification (RPID) tag that stores the data associated with the article, the method comprising the steps of: providing a RFID reading device configured to interrogate the RFID tag on each of the plurality of articles; coupling a conveyor means to the RFID reading device; and driving the conveyor means to move the RFID reading device to each of the plurality of articles, thereby allowing the RFID device to interrogate the RFID tag on each of the plurality of articles.
Brief Description of the Drawings
[0010] Preferred embodiments according to the present invention will now be described with reference to the Figures, in which like reference numerals denote like elements.
[0011] FIG 1 is a perspective view showing a movable RFID reading device coupled to a bookshelf in accordance with one embodiment of the present invention.
[0012] FIG 2 is an elevation view of the movable RFID reading device coupled to the bookshelf in FIG l.
[0013] FIG 3 is a block diagram illustrating the components of the RFID reading device according to one embodiment of the present invention.
[0014] FIG 4 is an elevation view of a plurality of movable RFID reading devices coupled to a bookshelf in accordance with an alternative embodiment of the present invention.
[0015] FIG 5 is an unassembled perspective view of the system and multiple bookshelves in accordance with an alternative embodiment of the present invention.
Detailed Description of the Invention
[0016] The present invention may be understood more readily by reference to the following detailed description of certain embodiments of the invention. [0017] FIG 1 and 2 illustrate an inventory system 1 for a library bookshelf 10 and the like. While the present invention is described in a library environment, the scope of the invention includes other environments such as warehouses in which articles are stored in shelves or racks. In a library environment, tracking and controlling books is an extremely labor intensive and error-prone process. Books are often misplaced in the bookshelves and
require manual search and relocation. The system 1 provides a more efficient method of tracking and verifying books placed on a bookshelf 10 by a librarian or user. For illustration purposes, in all the Figures the x-axis represents the horizontal direction and the y-axis represents the vertical direction. However, it is contemplated that the x and y axes are not only limited to horizontal and vertical directions.
[0018] The bookshelf 10 is used for storing books, journals, audio-visual products, and the like. Specifically, the bookshelf 10 comprises a base 12, a pair of side panels (14a, 14b), a top panel 16, and a plurality of shelves (18a, 18b, 18c, 18d). The side panels (14a. 14b) are rigidly mounted on the horizontal base 12, wherein the side panels (14a, 14b) extend vertically from the base 12 to the top panel 16. The plurality of shelves (18a, 18b, 18c, 18d) are coupled to the side panels (14a, 14b), wherein the plurality of shelves (18a, 18b, 18c, 18d) extend horizontally from side panel 14a to side panel 14b to support upright books 20 arranged in the typical side-by-side manner. Each book 20 is attached with a Radio Frequency Identification (RPID) tag 22 (not shown) that contains the information associated with the book. The bookshelf 10 may be fabricated in wood, metal or any other suitable bookshelf materials.
[0019] In a first embodiment, the system 1 of comprises a conveyor means 44 that moves a RFID reading device 50 to scan books 20 arranged on the plurality of shelves (18a, 18b, 18c, 18d). In particular, the conveyor means 44 is supported by a plurality of support bars 42 mounted on the bookshelf top panel 16, wherein the conveyor means 44 extends horizontally from side panel 14a to side panel 14b. The conveyor means 44 has a longitudinal member 46 that extends vertically from the bookshelf top panel 16 to the base 12. Furthermore, the conveyor means 44 may be driven by a servo-motor 48, or the like, to move the member 46 horizontally in x-directions. The conveyor means 44 can also be configured as a sliding rail that enables the member 46 to slide horizontally in x-directions. The RFID reading device 50 is coupled to the member 46, and can be configured to slide vertically along the member 46 in y-directions. For example in FIG 2, the servo-motor 48 drives the conveyor means 44 to move the RFID reading device 50 across shelf 18b. In particular, the RFID reading device 50 moves horizontally from position A to position B to interrogate all the tags 22 in the books 20 placed on shelf 18b. Similarly, the RFID reading device 50 can be moved back from position B to position A. An optional rail 45 may be disposed at base 12 of the bookshelf 10, wherein the rail 45 is configured to
receive the member 46. The rail 45 is provided to ensure better stability of the horizontal movement of the member 46. Furthermore, the RFID reading device 50 is slidable along member 46 to interrogate books 20 place on different shelves (18a, 18b, 18c, 18d). For example, the RFID reading device 50 slides vertically from position B to position C to interrogate books placed on shelf 18d. The above example serves to explain the movement of the RFID reading device 50 and in no way meant to limit the scope of the present invention. It is apparent to one skilled in the art that the movement of the RFID reading device 50 is not limited to the above examples and can include a combination of horizontal and vertical movements as well.
[0020] Besides providing a more efficient method of tracking and verifying books placed on the bookshelf 10, the system 1 gives an additional advantage of easy implementation on existing bookshelves 10. Furthermore, some libraries and warehouses have tall bookshelves 10 or racks for storing books 20 or articles. It is be difficult and maybe even hazardous for workers to reach these tall bookshelves 10 or racks. The present invention overcomes this problem by mounting the conveyor means 44 on the bookshelf 10, thus providing the RFID reading device 50 with the versatility to interrogate books 20 or articles in tall bookshelves 10 or racks.
[0021] The reading cycle of the RFID reading device 50 from position A to B will now be described. As mentioned above, the conveyor means 44 moves the RFID reading device 50 across shelf 18b horizontally to interrogate all the tags 22 in the books 20 placed on shelf 18b. In particular, the RFID reading device 50 transmits an interrogation signal when moving across shelf 18b. The speed of the servo-motor 48 can be pre-determined to ensure that the RFID reading device 50 performs proper interrogation of the tags 22 attached to each book 20.
[0022] Referring to FIG 3, the RFID reading device 50 comprises an antenna 52, a
RFID reader 54 and a communication device 56. The antenna 52, RFID reader 54 and communication device 56 are preferably enclosed in a housing made of plastic materials or the like. The antenna 52 is electrically coupled to the RFID reader 54 for sending interrogation signals to the RFID tags 22 attached in the books 20. The RFID reader 54 can be a high frequency (HF) reader, ultra-high frequency (UHF) reader, or any other known and unknown frequency readers. The RFID reader 54 may further be a combination of HF and UHF readers or a combination of any other known and unknown frequency
readers. In response to the interrogation signals, the tags 22 sends a response signal that contains the data associated with the books 20. Each tag 22 is configured to send a unique response signal that contains the data of each book 20. The RFID reader 54 detects the response signals via the antenna 52, wherein the RFID reader 54 is configured to decode the response signals to retrieve the data associated with the books 20. The reading cycle is complete when the RFID reading device 50 finishes interrogating all the tags 22 in the books 20 place along shelf 18b.
[00231 Subsequently, the RFID reading device 59 slides vertically along member
46 to interrogate books 20 arranged on the other levels of shelf (18a, 18c, 18d). For example, it is shown in FIG 2 that the RFID reading device 50 slides from position B to position C. Then the same reading cycle of the RFID reading device 50 is repeated to interrogate tags 22 attached to books 20 arranged on shelf 18d.
[0024] In addition, the RFID reader 54 is electrically coupled to the communication device 56 to send the data obtained during each reading cycle to a processing computer 60. The communication device 56 can be a wireless communication device such as Bluetooth or Wireless Fidelity (WIFI). However, it is contemplated that the RFID reader 54 can also be electrically hard-wired to the computer 60, wherein the RFID reader 54 transmits the data obtained during the reading cycle directly to the computer 60. The computer 60 can be programmed to send command signals to activate the RFID reader 54. Furthermore, the computer 60 is coupled to the servo-motor 48 to control the speed of the servo-motor 48 for driving the conveyor means 44.
[0025] The computer 60 contains a database of the books 20 in the library. In particular, the computer 60 is coupled to all the RFID readers 54 in the library bookshelves 10 to receive the data from the RFID readers 54. In use, the computer will compare the data received from each RFID reader 54 with the database to check whether there are missing or misplaced books 20 on a particular shelve 18. The computer then generates a report to alert the library staff of any missing or misplaced books 20 in the bookshelves 10. Librarians may then use this report to search for misplaced books 20 and relocate them on the correct bookshelves 10.
[0026] As discussed above, the antenna 52, RFID reader 54 and communication device 56 of the RFID reading device 50 are preferably enclosed in the same housing. In a second embodiment, the RFID reading device 50 only comprises the antenna 52. The
RFID reader 54 and communication device 56 is housed in a separate compartment 47 that is disposed on top of the member 46. By placing the RFID reader 54 and the communication device 56 in the separate compartment 47, the overall weight of the RFID reading device 50 is reduced. Thus, the mobility of the RFID reading device 50 along the member 46 is improved.
[0027] In a third embodiment, a plurality of RFID reading devices are coupled to the member 46. FIG 4 shows that the plurality of shelves (18a, 18b, 18c, 18d) and base 12 of the bookshelf 10 have corresponding RFID reading devices (50a, 50b, 50c, 5Od, 5Oe). Each of the RFID reading devices (50a, 50b, 50c, 5Od, 5Oe) comprises an internal antenna 52 for transmitting interrogation signals and receiving response signals. The antennas 52 in the plurality of RFID reading devices (50a, 50b, 50c, 5Od, 5Oe) can be coupled to the RFID reader 54 via a multiplexer 58 (not shown). The RFID reader 54 and multiplexer 58 can be housed in the compartment 47. As mentioned above, the RFID reader 54 is coupled to the communication device 56, wherein the communication device 56 is also housed in the compartment 47. An advantage of this embodiment is the use of a single RFID reader 54 coupled to the plurality of RFID reading devices (50a, 50b, 50c, 5Od, 5Oe), which significantly reduces the cost of implementing and maintaining the RFID equipment. [0028] In a reading cycle, the servo-motor 48 drives the conveyor means 44 to move the plurality of RFID reading devices (50a, 50b, 50c, 5Od, 5Oe) horizontally across the corresponding shelves (18a, 18b, 18c, 18d) and base 12 in x-directions. In this configuration, the plurality of RFID reading devices (50a, 50b, 50c, 5Od, 5Oe) provides the efficiency of interrogating all the books 20 stacked in the bookshelf 10 in a single reading cycle. Preferably, the strength of the interrogation signals emanating from the plurality of RFID reading devices (50a, 50b, 50c, 5Od, 5Oe) is pre-determined to provide effective interrogation without interference. For example, the RFID reading device 50a transmits an interrogation signal that is strong enough to interrogate all the tags 22 on shelf 18a but not the tags 22 on neighboring shelf 18b. Furthermore, the interrogation signal emanating from the RFID reading device 50a does not interfere with the interrogation signal emanating from the neighboring RFID reading device 50b. Alternatively, the plurality of RFID reading devices (50a, 50b, 50c, 5Od, 5Oe) are activated alternately to prevent interference of the interrogation signals emanating from the plurality of RFID reading devices. For example, RFID reading devices 50a, 50c, and 5Oe are activated in one
reading cycle to interrogate the tags 22 on shelves 18a, 18b and base 12. After the reading cycle is complete, RFID reading devices 50b and 5Od are activated to interrogate the tags 22 on shelves 18b and 18d.
[0029] In a fourth embodiment, the system 1 is disposed between two bookshelves
10 and 11 as shown in FIG 5. Bookshelf 11 can either be the same make as bookshelf 10 or different make from bookshelf 10. Here, the system 1 is the similar to the second embodiment described above. However, the RFID reading device houses two internal antennas 52a and 52b (not shown), wherein the antenna 52a would be activated for bookshelf 10 and antenna 52b would be activated for bookshelf 10. In one reading cycle, only one of the antennas 52a or 52b would be activated to interrogate the corresponding bookshelf (10, 11). A shield is preferably disposed between the two antennas (52a, 52b) to prevent any back-scatter interference between the two antennas (52a, 52b) during operation. For example, when antenna 52a is interrogating the tags at bookshelf 10, the shield will prevent the antenna 52a to receive signals from the tags 22 on bookshelf 11. [0030] Similar to the above discussion, the antennas (52a, 52b) can be coupled to the RFID reader 54 via a multiplexer 58. The RFID reader 54 and multiplexer 58 can be housed in the compartment 47. The RFID reader 54 is also coupled to the communication device 56, wherein the communication device 56 is also housed in the compartment 47. Alternatively, the plurality of RFID reading devices as discussed above may be implemented in the present embodiment.
[0031] In addition, the support bars 42 are extended to mount the system 1 between the bookshelf 10 and bookshelf 11. Also, the RFID reading device 50 is housed in a protective enclosure 50. In the library environment, the RFID reading device 50 may be subject to public interference and vandalism. The protective enclosure 50 prevents library users from meddling with the system 1, and particularly the RFID reading device 50. The protective enclosure 50 may be made from plastic or other suitable materials that does not interfere with the RFID reading device 50.
[0032] While the present invention has been described with reference to particular embodiments, it will be understood that the embodiments are illustrative and that the invention scope is not so limited. Alternative embodiments of the present invention will become apparent to those having ordinary skill in the art to which the present invention pertains. Such alternate embodiments are considered to be encompassed within the spirit
and scope of the present invention. Accordingly, the scope of the present invention is described by the appended claims and is supported by the foregoing description.