Electronic article surveillance markers for direct application to optically recorded media

ES 2 335 191 T3

DESCRIPTION

Electronic article surveillance markers for direct application to optically recorded media.

Field of the invention

This invention relates to specialized markers that are useful in magnetic-type Electronic Article Surveillance (VEA) systems, which can be applied directly to the surface of optically recorded media without having adverse effects on the performance or durability of the media. . The markers of the invention include single state markers and reversibly reactivatable dual state markers, both of which are useful in magnetic-type electronic article surveillance (VEA) or (EAS) systems.

Background

Magnetic-type VEA systems are generally used to prevent theft of merchandise such as clothing, books, cassettes, and compact discs. Electronic Article Surveillance (EAS) systems are frequently used to prevent unauthorized departure of items from a protected area, such as a bookstore or retail store. Typically, a VEA system includes an interrogation zone or corridor located near the exit of the protected area and markers or labels attached to the items to be protected. VEA systems are based on magnetic, RF, microwave and magnetic-restrictive technologies. Regardless of the particular technology involved, VEA systems are designed in such a way that the tag will produce a characteristic response when exposed to an interrogation signal in the corridor. Detection of this characteristic response indicates the presence of a sensitized tag in the corridor. The VEA system then initiates an appropriate security action, such as sounding an audible alarm, locking an exit door, etc. To allow the authorized exit of items from the protected area, tags that can be deactivated either permanently or reversibly (ie, dual status tags) are frequently used.

Although VEA markers have typically been used for the protection of optically recorded media such as compact discs and CD-ROMs, markers have generally been adapted to be attached to packages containing new compact discs and are not well adapted to be attached to their own. compact disc. For libraries and other institutions that repeatedly monitor CDs in and out to accommodate the needs of users and patrons, effective inventory control would prefer VEA markers to be attached to the CD.

Some markers have been developed to be attached directly to compact discs. One of these, available as "DCD-1" from 3M Company of St. Paul, MN, is a single marking band and security overlay that is attached to a compact disc. However, this marker has negative effects on the mechanical balancing of the disc, which can adversely affect the operation of modern high-speed CD-ROM drives, CD players, and other optically-recorded media playback equipment that require that the medium is mechanically balanced for proper operation. Another product, "CD Guard" available from Knogo North America Inc., Hauppage, Long Island, NY, suffers from the same mechanical balancing drawback. In US-A-5,347,508 an optical information storage disk is disclosed comprising an embedded dual-state, generally annular VEA marker. US-A-5,347,508 and DE-A-4,242,994 each describe optical information storage discs that comprise a VEA marker embedded in the disc during the manufacturing process.

Thus there is a need in the art for a marker specifically designed for the protection of optically recorded media.

Summary

The present invention relates to an Electronic Article Surveillance (VEA) marker for optically recorded media as defined in claim 1 and to an optical disc as defined in claim 14. The dependent claims refer to individual embodiments of the invention .

The invention is a VEA marker adapted to be applied directly to optically recorded media such as compact discs, CD-ROMs, laser discs, digital video discs, and the like. The marker includes a backing sheet and one or more marker elements that are positioned so that the mass distribution of the marker is symmetrically disposed around the center of the marker. This ensures that when the marker is properly positioned on the optically etched medium, the marker will not adversely affect the mechanical balance of the medium.

Brief description of the figures

The various objects, features, and advantages of the present invention will be better understood after reading and understanding the following detailed description and accompanying drawings, in which:

Figure 1 shows an embodiment of a marker according to the present invention;

Figures 2A and 2B show side views of the marker of the type shown in Figure 1;

Figure 3 shows a simplified side view of a dual status marker element;

Figures 4A and 4B show side views of two embodiments of the marker of the present invention attached to a compact disc;

Figures 5A and 5B show plan views of alternative bi-directional response dual state markers;

Figures 6A and 6B show plan views of alternate markers, designed to force marker elements to be in the unrecorded region of a compact disc;

Figures 7, 8, 9 and 10 show processes for producing markers of the present invention.

Detailed description

In the following detailed description, reference is made to the accompanying drawings that form a part thereof, and in which a specific embodiment in which the invention may be practiced is shown by way of illustration. It being understood that other embodiments and structural changes can be used without departing from the spirit and scope of the present invention.

The invention is an Electronic Article Surveillance (VEA) marker adapted for direct application to optically recorded media such as compact discs, CD-ROMs, laser discs, digital video discs, and the like. To simplify the illustration, the following detailed description will frequently refer to the specific case of compact discs; however, those skilled in the art will readily recognize that the markers described herein are applicable to any optically etched medium.

The VEA marker for this application is easy to apply to an exposed surface of the optically etched medium, provides good detection performance, does not interfere with the physical operation of the medium, or the equipment to read the medium, and does not damage the medium to short or long term. Specifically, the marker adhesive must not chemically react with any of the materials used in the medium, and the marker installation must not adversely affect the mechanical balance of the medium. Furthermore, the marker should preferably be compatible with the performance characteristics of the detection and activation / deactivation equipment in use in conjunction with the VEA system.

A first embodiment of an electronic article surveillance (VEA) marker 10 for optically recorded media is shown in plan in Figure 1 and in side view in Figure 2. The marker includes a centered circular fastener sheet 12 having, a concentric circular hole 14, and two marker elements 16 and 18 positioned so that the mass distribution of marker 10 is arranged symmetrically around the center of marker 10. This ensures that when the marker 10 is properly positioned on a compact disc, the marker has no negative effects on the mechanical balance of the disc. Mechanical balancing of the disc is very important for the proper operation of high-speed drives for CD-ROMs, CD players, and other optically recorded media playback equipment. The marker 10 also includes an adhesive layer 24 (Figure 2A) that is used to bond the marker to the compact disc.

The hole 14 in the backing sheet 12 acts as an alignment mechanism and serves to assist the user in properly positioning the marker on the compact disc or other optically recorded medium. The hole 14 is centered in the backing sheet 12 and is of a size and shape that substantially corresponds to the hole in a typical CD, CD-ROM, laser disk, or other optically recorded medium. Markers are preferably adapted to different media by providing markers with different sized backing sheets and centered holes that correspond to the physical size of the medium in question. To attach marker 10 to a compact disc, the user simply orients hole 14 with the hole in the middle. When the two holes are aligned, the marker can be attached to the middle. By properly positioning the marker in the medium, the mechanical balancing of the marker ensures that the presence of the marker in the medium will not adversely affect the performance of the medium or any reproduction medium, such as CD players or CD ROM drives.

In an alternative embodiment, shown in Figure 2B, a marker 11 also includes a release liner 23 on top of the adhesive layer 24. The release liner protects the adhesive layer 24 from damage and accidental bonding to other surfaces. To bond the marker 11 to a compact disc, the release liner is removed, exposing the adhesive layer 24, which is then used to bond the marker to the compact disc.

Marker elements 16 and 18 can be dual or single state. If marker elements 16 and 18 are single state, marker elements 16, 18 will consist of a layer of high permeability magnetic material that produces a low coercive force signal. For a dual status marker, one of several possible alternative embodiments is shown in Figure 3. Figure 3 shows a side view of an element

ES 2 335 191 T3 dual status marker of the type described in US-A-3,765,007. Dual state marker 18 includes a low coercive force signal producing layer 32, high permeability magnetic material, and a signal blocking layer 34 that includes a plurality of segments 36 of remanently magnetizable magnetic material.

In alternative embodiments, the signal blocking layer 34 can be a contiguous layer of magnetic material that can be remanently magnetized.

Referring back to Figure 1, markers 16 and 18 are preferably in parallel alignment and symmetrically arranged on opposite sides of hole 14. In a preferred embodiment, the marker elements 16 and 18 are furthermore preferably located with their inner edges separated by a distance greater than 4 cm, and the dimensions of the marker elements 16 and 18 are further selected such that their maximum radial extension, from the center of the hole 14 is less than about 5.9 cm.

Figure 4A shows a side view of the marker 10 attached to a surface of a compact disc 28. The holding sheet 12, the marking element 18 and the adhesive layer 24 are attached to a first side 26 of the compact disc 28 with the adhesive layer 24. Preferably, the first side 26 is the non-recordable side or "label" side of the compact disc 28, while the second side 30 of the compact disc 28 is the optically detectable recorded surface 30. In this embodiment, the backing sheet is preferably designed to remain attached to the compact disc 28, and functions to protect the marker elements 16 and 18 from damage and deterioration.

In an alternative embodiment, shown in Figure 4B, the backing sheet 12 is designed to be removable. In this embodiment, the adhesive 24 with which the marker elements are attached to the compact disc must be more aggressive than the adhesive (not shown) with which the marker elements are attached to the backing sheet. In this manner, once the marker elements are attached to the compact disc 28, the backing sheet can be removed, leaving the marker elements 16 and 18 attached to the surface of the compact disc. This embodiment may be preferred for certain applications where the additional weight of the backing sheet may be undesirable if left attached to the compact disc.

For compact disc applications such as that shown in Figure 4A, the backing sheet is preferably clear and colorless, allowing information printed on the surface 26 of compact disc 28 to be easily read while providing protection for the elements. bookmarks and tag. For selected compact disc applications, it may be preferred for at least portions of the backing sheet 12 to contain white pigment and / or having a printable surface so that the backing sheet can function as a label.

In addition to the embodiments shown in Figures 2A-B and 4A-B in which the marker is a stack of elements comprising the backing sheet 12, the marker elements 16 and 18, and the adhesive layer 24, it will be understood that other embodiments in which the order of the elements is changed are also within the scope of the invention. For example, the order of elements could be backsheet 12, adhesive layer 24 with marker elements 16 and 18 on top of adhesive layer 24, without departing from the scope of the present invention.

Adhesive materials suitable for use as adhesive layer 24 preferably have chemically inert characteristics in terms of interaction with any of the materials used in the construction of optically recorded media or their labels. In other words, the adhesive 24 is preferably not reactive with any of the materials used in the construction of the medium or its label. Additionally, no material used in the adhesive layer 24 can flow or migrate out of the layer so as to come into contact with the actuators or other internal parts of the reproductive equipment, storage containers, etc., or corrode the reflective coating of the medium, etc. A preferred adhesive can be obtained as Transfer Adhesive No. 9461P from 3M Company Inc. of St Paul MN.

In an illustrative embodiment of marker 10 the backing sheet 12 is a circular segment of transparent polyethylene terephthalate film having a thickness of 50 microns (2 mils) and a diameter of 11.4 cm (4.5 inches). . The center hole 14 has a diameter of 1.7 cm (0.67 inches). Marker element 18 is approximately 3 inches (7.7 cm) long and 40 thousandths of an inch (1 mm) wide. The signal produced by layer 32, which co-extends with marker element 18, is approximately 18 microns (0.7 mils) thick and is made of an amorphous magnetic alloy consisting of approximately 67% (atomic percent ) Co, 5% Fe, and 25% B and Si, which is commercially available from AlliedSignal Corp. of Parsippany, New Jersey, as product No. 2705M. The signal blocking layer 34 includes a plurality of spaced segments, each approximately 5 mm long and 40 microns thick, and the same width as the signal producing layer, made of a commercially available FeCr alloy. such as ArnoKrome 3 from Arnold Engineering of Marengo Illinois. In the preferred embodiment, the Arnokrome 3 samples used in the example marker were subjected to a tempering procedure to achieve a uniform coercivity of 200 +/- 30 Oersteds. Also in the preferred embodiment, product samples # 2,705M were tempered to reduce coercivity and increased anisotropy in the cross-membrane direction. Although specific materials are described herein, it should be understood by those skilled in the art that different materials and different marker constructs could be used without departing from the scope of the present invention.

In one embodiment, marker elements 16 and 18 are preferably substantially equal in dimensions, material specifications, and in the characteristic signals that they produce when interrogated in the active state.

ES 2 335 191 T3 vo by a VEA system. In an alternate embodiment, the marker elements are dissimilar in dimensions, material specifications, or both to produce a combined characteristic signal that is detectably different from the characteristic signals of individual marker elements, ambient noise signal sources, etc.

An alternative form of dual-state Electronic Article Surveillance (VEA) markers 60 is shown in Figure 5A. Marker 60 is similar to that described in US-A-4,829,288. Marker 60 comprises a circular backing sheet 62 having a centered, concentric circular hole 64 and further comprises four elongated narrow rectangular marker elements 66, 68, 70 and 72. Marker elements 66, 68, 70, and 72 are preferably arranged symmetrically around the center of hole 64, and in a preferred embodiment, the inner edges of elements 66, 68, 70, and 72 form a square. In a specific embodiment, elements 66, 68, 70, and 72 are positioned so that their closest distance apart from the center of the marker is preferably at least 1.9 cm. The length and width dimensions of marker elements 66, 68, 70, and 72 are selected so that their maximum radial extension, from the center of hole 64, is preferably less than about 5.9 cm. Individual marker elements 66, 68, 70, and 72 act as orthogonal switch elements, allowing marker 60 to have a "bi-directional" response. Although markers 66, 68, 70 and 72 are illustrated in Figure 5A, in one embodiment in which the ends of the elements are physically separated from each other, those skilled in the art will readily recognize that other embodiments in which the ends Adjoining marker elements being in contact with each other are also within the scope of the present invention. Also, VEA markers having an odd number of marker elements in non-orthogonal arrangements such as a VRA marker (not shown) having marker elements in an equilateral triangular arrangement are also well within the scope of the present invention. Once again, an important feature is that the mass of the marker is symmetrically arranged around the center of the marker, thus ensuring that the mechanical balance of a compact disc is maintained after the marker is attached.

An alternate form of "bidirectional response" dual state marker is shown in Figure 5B. Marker 76 is similar to those described in US-A-4,746,908, US-A-4,895,197 and US-A-4,967,185. Marker 76 comprises a circular backing sheet 12, and a single marker element 80 comprising a contiguous signal producing layer that extends around central hole 14 of holding sheet 12. Marker 76 has corner areas 84, 86, 88, and 90 that act as flux getters to focus the magnetic flux of the interrogation field through interconnected members 92, 94, 96, and 98, which serve as the elements. detectable switchgear.

The above-described embodiments are useful for those compact discs that are for recording or are recorded on only one surface. For compact discs or laser discs that can be recorded on both surfaces, or for those applications where it may be desired to mark the recorded side of a single-sided compact disc, a marker such as those shown in Figures 6A may be preferred. and 6B. The marker of Figure 6A includes two marker elements 17 and 19 on a backing sheet 12, which has a centered, concentric circular hole 14. Marker 40 of Figure 6B includes a single marker element of the type shown in Figure 5B. A ring shown in Figures 6A and 6B as a hidden line 13 corresponds to the non-recordable "cube" region of the optically etched. This unrecorded region 13 is the portion of the compact disc where the compact disc is held in a CD ROM drive or CD player. For most compact discs the unrecorded region has a radius of approximately 1.9 cm, although it should be understood that for this embodiment, the marker elements only need to be within the cube region of the optically recorded medium, regardless of their location. particular dimension.

In the embodiments shown in Figures 6A and 6B, marker elements 17, 19, and 41, respectively, are positioned at markers 20 and 40, respectively, such that the marker elements are attached to the unrecorded region of the compact disc. By keeping the marker elements within the unrecorded region of the compact disc, the marker elements cannot interfere with the disk reading mechanism of a CD ROM drive or CD player. Furthermore, the marker elements are once again carefully positioned to maintain the mechanical balance of a compact disc to which they have been properly attached.

In Figures 7-10, a process for producing dual state markers 10 of the type shown in Figure 1 is shown. In Figure 8, it is shown, in an end view, a continuous VEA marker building membrane 100 that is produced by first bringing the magnetizable foil strips 110 remanently into contact properly aligned with the high permeability magnetic foil strip 102 and laminating an adhesive-coated tape side 104 on the exposed surfaces of sheet 102 and sheet 110 carrying them into contact under pressure between tensioning drums 112 and 114.

Figure 9 shows the next stage of the procedure, in which a marker construction 100 is brought to a cutting station 120 that cuts a narrow strip to form a marker element 16 with its long dimension equal to the width of marker construction 100 , and releasably adhering marker element 16 to an adhesive side 118 of the lower path of a temporary carrier band 116. In a preferred embodiment, the adhesive side 118 of the carrier band 116 is coated with pressure sensitive adhesive on the adhesive side 118. An illustrative carrier band is tape No. 295, available from 3M Company of St. Paul, MN. . However, other suitable pressure sensitive adhesive carrier strips could be used.

ES 2 335 191 T3

At station 120, guides and positioning means convey the substantially continuous marker construction strip 100 in a direction that is orthogonal to the direction in which the carrier band 116 is conveyed such that the marking elements 16 thus formed align. intrinsically with its long dimension along the long dimension of the carrier band 116. The guides and positioning means for the two orthogonal bands are positioned so that the marker elements will adhere in an off-center position when applied to the carrier band 116. A series of off-center marker elements 16 are applied sequentially along the length of the carrier band 116 by incrementally advancing the position of the carrier band 116 after each marker element is cut and applied to its underside surface.

In a first embodiment, the other marker elements 18 are applied to the adhesive surface 118 of the lower leg of the carrier band 116 at opposite off-center positions of the marker elements 16 by rotating the carrier band 180 ° after the marker elements 16 are applied. , and re-transporting the carrier web 116 through the cutter station 120. In procedures where the carrier web 116 is rewound on its supply drum after the markers 16 are applied, the carrier web 116 must be conveyed through the cutting station 120 in the opposite direction to allow for proper off-center positioning of the markers. marker elements 18. In an alternative method variation, the carrier band 116 with marker elements 16 attached to the adhesive surface 118 is temporarily retained on the tensioner drum and the tensioner roller is removed and installed in the position of the original supply roller. Carrier band 116 is then transported through cutter station 120 in the same direction used for installation of marker elements 16 to accomplish off-center positioning and bonding of marker elements 18. This ensures that the proper positioning of marker elements on the marker to ensure proper mechanical balancing of a compact disc when the marker is attached to it.

In another alternative procedure variation, shown in Figure 10, the carrier web 116 is transported sequentially through the cutting station 120, which applies marker element 16, and a second cutter station 120 'that applies a marker element 18 at the opposite off-center position. The spacing between the cutting stations 120 and 120 'is designed so that the marker elements 16 and 18 are aligned to achieve a properly balanced marker. Figure 10 shows the marker construction 100 from which the marker elements 16 are cut, moving into the cutting station 120, a marker construction 100 'from which the marker elements 18 are cut, moving into the cutting station 120 '. The constructs of markers 100 and 100 'may optionally be identical, or they may differ such that marker element 18 has characteristics of producing different signals from marker element 16.

The product formed by any of the aforementioned process variations, comprising carrier band 116 with marker elements 16 and 18 applied to its bottom path adhesive surface, is a VEA marker transfer sheet 130. Transfer sheet 130 can be used for marker elements to any other adhesive surface. For example, transfer sheet 130 could be used to transfer marker elements to the adhesive surface of the upper limb of a backing sheet such as circular backing sheet 12, shown in Figures 1 and 2. Transfer sheets 130 VEA markers of the invention are also useful for transferring marker elements to adhesive surfaces of other objects, product labels or packages. For these different uses, different marker configurations and / or dimensions could be used than the specific marker embodiments shown here, as they may not have the mechanical balancing requirements of a compact disc.

In another embodiment, with the addition of an adhesive layer 24 on the marker side of the carrier band 116, the carrier band 116 of the transfer sheet 130 could function as the fastening sheet 12 of any of the markers shown in the Figures. 1, 5A-B or 6A-B, in the case that the support sheet 12 can be removed as shown in Figure 4B.

In a variation of the methods of Figures 7-10 described above, the marker elements of any of the marker embodiments described above could be attached directly to a backing sheet 12 rather than to a temporary carrier sheet 116.

In an alternate embodiment of the VEA marker transfer sheet of the invention, not shown, an upper limb adhesive layer and a release carrier sheet are laminated or otherwise applied to the side of the marker construction 100. VEA, opposite the side that will adhere to the surface 118 of the carrier band 116, before the construction 100 enters the cutting stations 120. Similarly, a top leg adhesive layer and a release carrier sheet would be laminated or otherwise applied to the side of the VEA 100 'marker construction before it is inserted into the cutting station 120', if two stations were used. cutting. After removal of the release carrier layer from each marker element, the resulting transfer sheet 130 is suitable for the direct application of a dual-state electronic article surveillance (VEA) marker of the invention to a label surface of a compact disc or other item. For the application of useful marker elements to items other than compact discs, different configurations and / or dimensions may be required or preferred.

Although specific embodiments have been shown and described herein for purposes of illustration of representative embodiments, it will be understood by those of ordinary experience that a wide variety of alternate and / or equivalent embodiments designed to achieve the same purposes may be substituted for the specific embodiments.

ES 2 335 191 T3 shown and described without departing from the scope of the present invention. Those of ordinary skill will readily appreciate that the present invention could be carried out in a wide variety of embodiments. This application is intended to cover any adaptations or variations of the preferred embodiments discussed here. It is therefore intended that this invention be defined by the claims and equivalents thereof.