Patent Application
20050040272
1. Field of the Invention
This invention relates generally to data cartridges that incorporate a memory device for data storage and transmission. In particular, the invention concerns a specific data-cartridge geometry for radio-frequency communication with external reading devices along multiple orthogonal axes.
2. Description of the Related Art
The portability of magnetic tape cartridges makes it possible to store large amounts of data in separate cartridges that can then be stored in libraries for repeated use or archived for future use. Such data cartridges often include a memory chip with information that is more readily accessible than the data stored on the tape by establishing a connection with external reading devices. Thus, the information carried in the memory chip can be quickly accessed without reading the contents of the tape.
According to earlier implementations of this concept, the memory chip inside the cartridge is connected to electrical conductors that extend to the outer surface of at least one of the walls of the cartridge case. An external reading device, typically mounted in a tape drive, is adapted to contact the electrical conductors in order to energize the memory chip and receive its contents through the conductors. In other implementations of the concept, an antenna is coupled to the memory chip for non-contact data transmission. A second antenna, coupled to the reading device, is used to energize the chip and receiving its contents using a magnetic field. See, for example, Patent Publications JP2002117644, JP2002140879, US20010011012, US20030002214 and US20030021058.
In order to allow communication with external devices along multiple axes, the antenna associated with the memory chip in the cartridge has been extended in multiple directions, such as along the rear and side walls or the back and bottom walls of the cartridge case. Accordingly, data may be received by reading devices placed at orthogonal directions with respect to the cartridge. In a two-axis implementation of this concept disclosed in U.S. Pat. No. 6,304,416, the memory chip and antenna are positioned at a 45-degree angle with respect to the rear and bottom walls of the cartridge case, thereby enabling transmission along both the horizontal and vertical planes. The antenna and memory chip are anchored to the inner surfaces of the walls of the cartridge case so as to minimize the distance from the antenna of the external reading device while in operation.
Thus, non-contact magnetic-field data transmission along two orthogonal axes has been achieved with a memory-chip device mounted at an angle inside the tape cartridge. Because of magnetic-field power limitations, these devices necessarily operate at very low power levels (in the order of 50 milliwatts). On the other hand, a sufficiently strong field needs to be propagated to energize the memory chip and effectively transmit data between antennas. Thus, it is very desirable to eliminate any structural component in the cartridge that attenuates the data-transmission signal and to minimize the distance between the memory-chip antenna and the antenna of the reading device outside the tape cartridge. This invention provides a novel cartridge case designed to optimize these objectives.
According to the principles of the present invention, a tape cartridge case has the same general geometry and dimensions of a conventional cartridge, but an additional slanted wall is incorporated between two other walls at one end of the cartridge case. A memory chip is placed with its antenna adjacent to the additional wall inside the case. Thus, the memory chip may be accessed by non-contact means from two substantially orthogonal directions.
According to one desirable aspect of the invention, the memory-chip/antenna device may be attached to the case without supporting ribs or other structural components that inhibit the free propagation of the electromagnetic wavefront between the antennas of the memory chip and the reading device. According to another, most advantageous aspect, the elimination of the corner between two perpendicular walls of the cartridge case allows the external reading device to be placed closer to the antenna of the memory chip inside the cartridge. As a result, improved data transmission is achieved with the very low RF power levels normally used for energizing the memory chip.
In the preferred embodiment of the invention, the slanted wall and the antenna of the memory chip are oriented at approximately 45 degrees with respect to the adjacent cartridge walls. The slanted wall is disposed between the rear and the bottom walls of the cartridge case and the resulting free space outside the case (the space contained within the imaginary corner defined by the intersection of the planes of the rear and bottom walls) is used to minimize the distance between the memory-chip antenna and the one or two reader antennas facing the rear and/or bottom walls when the cartridge is in place for data transmission.
Various other purposes and advantages of the invention will become clear from its description in the specification that follows and from the novel features particularly pointed out in the appended claims. Therefore, to the accomplishment of the objectives described above, this invention consists of the features hereinafter illustrated in the drawings, fully described in the detailed description of the preferred embodiment and particularly pointed out in the claims. However, such drawings and description disclose only some of the various ways in which the invention may be practiced.
The heart of this invention lies in the recognition that the elimination of a corner section from two adjacent walls in the casing of a conventional tape cartridge would reduce the space occupied by the cartridge when placed in operation for RF data transmission. Accordingly, the freed space advantageously enables the placement of the antennas of one or more external reading devices in closer proximity than heretofore possible to the antenna of the memory chip mounted inside the cartridge.
For the purposes of this disclosure, the terms rear and front are used throughout in connection with the structure of a typical tape cartridge described herein to refer to the side facing the gripper arms of an automated picker and the side facing the drive during use, respectively. Left and right refer to the cartridge lateral sides as they appear viewing the cartridge from its front side. The terms bottom and top are used with reference to the side of the cartridge that contains the tape reel and hub and to its parallel opposite side, respectively. The top and bottom sides are considered to lie on horizontal planes during normal use of the cartridge. The term slanted is used to refer to a wall that is disposed at an angle either with respect to a pair of horizontal and vertical walls or with respect to two vertical walls of the cartridge. Finally, the term angle is used to refer to the space defined by the intersection of two planes.
Referring to the drawings, wherein like parts are designated throughout with like numerals and symbols,
As a result of this configuration, the antenna 20 is capable of non-contact transmission in multiple directions including along vertical and horizontal planes parallel to the rear and bottom walls, respectively, as required for conventional two-axis communication. In addition, as illustrated in
According to another aspect of the invention intended to further improve non-contact communication between the internal and external antennas, the memory chip and antenna 18,20 are preferably attached to the inside surface of the slanted wall 12 (or 32, as applicable) using molded retaining features 38 in the case (see
Thus, a new design for a magnetic-tape cartridge is provided which can be used to enhance transmission for multiple-axis non-contact communication. It is understood that the invention may be used with any cartridge format, such as Magstar or LTO, currently in use in the art. Moreover, the invention has been described with a slanted wall 12 that spans most of the length of the rear wall of the cartridge, but one skilled in the art would readily recognize that only the portion of wall facing the antenna 20 of the memory chip needs to be modified according to the invention. Similarly, the slanted wall could be recessed with respect to one or both of the adjacent walls, as illustrated in the embodiment 40 of
Various changes in the details, steps and components that have been described may be made by those skilled in the art within the principles and scope of the invention herein illustrated and defined in the appended claims. For example, the memory-chip antenna has been described as being attached to the interior surface of the slanted wall of the invention, but it is clear that equivalent embodiments could be obtained by incorporating the antenna within the wall itself, or by attaching it to the exterior surface of the wall, as illustrated in
Therefore, while the invention has been shown and described in what is believed to be the most practical and preferred embodiments, it is recognized that departures can be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent articles and processes.
