GB2247594A - Tags for use in electronic article surveillance systems. - Google Patents

Abstract

A deactivatable tag is useable with an electronic article surveillance system and comprises planar conductive material cut into a pair of inverse, first and second spiral conductors 25, 30 positioned on opposite sides of a dielectric layer 28T for capacitive and inductive coupling to form a resonant circuit connector portions 27, 32 which are free of dielectric and adhesive are connected to one another by soldering or welding, eg. by a laser beam. The tag may be deactivated by a strip (118), (Figs 17 to 20), which becomes effective to short out spiral 30 upon application of heat but which does not do this during the welding operation. The tags may be formed into a longitudinal web, and a continuous conductive material, film or coating applied thereto to help prevent deactivation from electrostatic discharge. <IMAGE>

Description

TAGS FOR USE IN ELECTRONIC ARTICLE SURVEILLANCE SYSTEMS AND METHODS OF MAKING THEM This application is divided out of application no. 8824551.9. - -.

This invention relates to tags for use in electronic article surveillance systems, to tag webs including a series of such tags, and to methods of making such tags.

The invention is concernedwith improvements in the invention of our.U.K. Patent Application GB 2,197,565 published 18th May 1988.

The. prior art includes. the following documents US Patents 3,240,647; 3,624,631; 3,810,147; 3,913,219; 4,369,55.7; 4,482,874; 4,541,559; 4,555,414; 4,555,291; 4,567,473; and 4,689,636; and French Patent 2,412,923.

The present invention in its various aspects is defined: in the appended claims to which reference should.now be made.

It has been found. that although the invention according- to the embodiments of FIGURES 22 to.

.25 (described below). has greatly decreased the incidence of premature deactivation of. a series of connected.,deactivatable tags during. manufacturing, further. .improvementscan be be attained by eliminating electrostatic charges on'the tag web in accordance with the present invention. It-was also found that in spite of the improvement resulting from-the embodiment of.EIGURES 22 through 25, premature deactivation could occur when the tag web was printed on commercially available printers which typically generate electrostatic charges. In that such charges are passed..to-the tag web by the printer., and s.uch.charges remain in the tag web, it has happened that tags..are deactivated through interaction of the deactivator and the resonant circuit on each .tag. ~ One-feature-of the presentinvention is to help obviate this problem during printing on. the tag web in;a printer: or. other static-producing- ..- - handling device.

In accordancewith a--:fir:st aspect - of the invention; there is provided. a. - method of making tags for use in an electronic article surveillance system, comprising the steps of: providing a web having a series of first conductors, providing:another web having a series of second conductors, positioning the webs so that the first and second conductors are in adjacent pairs and the first and second conductors of each pair are spaced apart by d-ie-lectri-c material, and using a-laser beam to weld adjacent portions of the first and second conductors of each pair so--that each pair provides a detectable resonant circuit In accordance with a further aspect of the invention there is provided a method of making tags for use in an electronic article surveillance system, comprising the steps of: providing a web having a series of first conductors, providing another web having a series of second conductors, wherein at least one of the conductors- is a spiral conductor, depositing welding material on each conductor of one of said series, positioning a- deactivator adjacent one conductor of one of said series, wherein the deactivator includes heat activatable material rendered conductive by the application of heat, positioning the webs so that the first and second conductors are in adjacent pairs spaced apart by dielectric material to provide a tag web, and applying heat to the' tag web at a temperature high enough to cause the welding material to weld the conductors to each other to provide a detectable resonant circuit but low enough to prevent the activatable material from being rendered conductive.

Brief Description of the Drawinqs FIGURE 1 is an exploded perspective view of a tag in accordance with an embodiment of the invention FIGURE 2 is a fragmentary sectional view of .the tag shown in FIGURE.1; FIGURE 3 is a diagrammatic perspective view illustrating method off making tag. in accordance with the invention; FIGURE 4 is a.diagrarntnatic. top plan view showing a mask having been applied to a first adhesive coated web and showing an electrically conductive web. being laminated to. the masked first -adhesive coated web; FIGURE. 5 is a diagrammatic'. top plan; view.

showing the conductive web.having.been.cut to provide first. and second. pairs of conductors and showing a masked.second adhesive coated. web being laminated to the. conductive web; FIGURE 6 is a diagrammatic top plan view showing the first coated web with the first conductors adhered thereto being separated relative to the second coated web with the second conductors adhered thereto, and showing further the first coated web having been recoated with adhesive and two webs of dielectric being laminated to the recoated first coated web, and showing the dialectric webs having been coated with adhesive; FIGURE 7 is a diagrammatic top plan view showing the second coated web with the second conductors adhered thereto having been shifted and laminated over and to the dialectric webs and to the first coated web with the first conductors to provide a composite tag web, showing the staking of the first and secohd conductors of each tag to provide resonant circuits for each tag, and showing slitting of the composite tag web to provide a plural series of composite tag webs; FIGURE 8 is a vertically exploded view showing the first and second coated webs with the first and second conductors that result from cutting the electrically conductive web spirally; FIGURE 9 is a top plan view showing the first and second coated webs shifted by a distance equal to the width of one conductor spiral plus the width of one conductor; FIGURE 10 is a top plan view of two tags with the dialectric web shown in phantom lines; FIGURE 11 is a fragmentary perspective view which, when taken together with the preceding figures of the drawings, illustrates an improved method of making deactivatable tags; FIGURE 12 is a fragmentary top plan view taken along line 12--12 of FIGURE 11; FIGURE 13 is a sectional view taken along line 13--13 of FIGURE 12; FIGURE 14 is a fragmentary perspective view similar to FIGURE 1, but showing one embodiment of structure for deactivating the tag; FIGURE 15 is a fragmentary top plan view of the tag shown in FIGURE 14; FIGURE 16 is a fragmentary perspective view which, taken together with FIGURES 1 through 10, illustrated an alternative improved method of making deactivatable tags; FIGURE 17 is a fragmentary top plan view taken along line 17--17 of FIGURE 16; FIGURE 18 is a sectional view taken along line 18--18 of FIGURE 17; FIGURE 19 is a fragmentary perspective view similar to FIGURE 14 but showing another embodiment of structure for deactivating the tag; FIGURE 20 is a fragmentary top plan view of the tag shown in FIGURE 19; FIGURE 21 is a sectional view similar to FIGURE 18 but showing an alternative structure for deactivating the tag; FIGURE 22 is a top plan view of an alternative cut pattern for the web of conductive material corresponding generally to D in FIGURE 5; FIGURE 23 is a top plan view of the alternative cut pattern with one-half of the conductive material removed and corresponding generally to G in FIGURE 6; FIGURE 24 is a diagrammatic perspective view showing the manner in which the webs of deactivating material are cut into stripes or strips; FIGURE 25 is a top plan view of a pair of longitudinally spaced resonant circuits with separate respective deactivator strips; FIGURE 26 is a fragmentary, diagrammatic, perspective view showing the portion of a tag making process which incorporates the present invention; FIGURE 27 is a top plan view similar to FIGURE 25, but incorporating the invention also illustrated in FIGURE 26; FIGURE 28 is a sectional view taken generally along line 28--28 of FIGURE 27; FIGURE 29 is a fragmentary perspective view showing an alternative arrangement for welding the spiral conductors to each other; FIGURE 30 is a sectional view taken generally along 30--30 of FIGURE 29; FIGURE 31 is a fragmentary perspective view showing a portion of FIGURE 3 modified in accordance with one embodiment of the invention; FIGURE 32 is a bottom plan view of the tag web in accordance with the invention; FIGURE 33 is a fragmentary perspective view showing a portion of FIGURE 3 modified in accordance with another embodiment of the invention; and FIGURE 34 is a fragmentary perspective view showing a portion of FIGURE 26 modified in accordance with yet another embodiment of the invention.

Description of the Preferred Embodiments Referring initially to FIGURE 1, there is shown an exploded view of a tag generally indicated at 19. The tag 19 is shown to include a sheet 20T having pressure sensitive adhesive 21 and 22 on opposite faces thereof. A mask 23 in a spiral pattern covers a portion of the adhesive 21 and a release sheet 24T is releasably adhered to the adhesive 22.

The mask 23 renders the adhesive 21 which it covers non-tacky or substantially so. A conductor spiral indicated generally at 25 includes a spiral conductor 26 having a number of turns. The conductor 26 is of substantially the same width throughout its length except for a connector bar 27 at the outer end portion of the conductor spiral 26. There is a sheet of dielectric 28T over and adhered to the conductor spiral 25 and the underlying sheet 20T by means of adhesive 29. A conductor spiral generally indicated at 30 includes a spiral conductor 31 having a number of turns. The conductor 31 is adhered to adhesive 29 on the dielectric 28T. The conductor 31 is substantially the same width throughout its length except for a connector bar 32 at the outer end portion of the conductor spiral 30. The conductor spirals 25 and 30 are generally aligned in face-to-face relationship except for portions 33 which are not face-to-face with the conductor 26 and except for portions 35 which are not face-to-face with the conductor 31. A sheet 37T has a coating of a pressure sensitive adhesive 38 masked off in a spiral pattern 39. The exposed adhesive 38' is aligned with the conductor spiral 30.

Adhesive is shown in FIGURE 1 by heavy stippling and the masking is shown in FIGURE 1 by light stippling with cross-hatching. The connector bars 27 and 32 are electrically connected, as for example by staking 90. It should be noted that the staking'90 occurs where connector bars 27 and 32 are separated only by adhesive 29. There is no paper, film or the like between the connector bars 27 and 32. Accordingly, the staking disclosed in the present application is reliable.

With reference to FIGURE 3, there is shown diagrammatically a method for making the tag 19 shown in FIGURES 1 and 2. A roll 40 is shown to be comprised of a composite web 41 having a web 20 with a full-gum or continuous coatings of pressure sensitive adhesive 21 and 22 on opposite faces thereof. The web 20 is "double-faced" with adhesive. A release liner or web 42 is releasably adhered to the upper side of the web 20 by the pressure sensitive adhesive 21, and the underside of the web 20 has a release liner or web 24 releasably adhered to the pressure sensitive adhesive 22. As shown, the release liner 42 is delaminated from the web 20 to expose the adhesive 21. The adhesive coated web 20 together with the release liner 24 pass partially about a sandpaper roll 43 and between a pattern roll 44 and a back-up roll 45 where mask patterns 23 are applied onto the adhesive 21 to provide longitudinally recurring adhesive patterns 21'. Masking material from a fountain 46 is applied to the pattern roll 44. With reference to FIGURE 4, the portion marked A represents the portion of the web 20 immediately upstream of the pattern roll 44. The portion marked B shows the mask patterns 23 printed by the roll 44. The patterns 23 are represented by cross-hatching in FIGURE 4. With reference to FIGURE 3, the web 20 now passes through a dryer 47 where the mask patterns 23 are dried or cured. The adhesive 21 is rendered non-tacky at the mask patterns 23. A web 49 of planar, electrically conductive material such as copper or aluminum from a roll 48 is laminated onto the coated web 20 as they pass between laminating rolls 50 and 50'. Reference character C in FIGURE 4 denotes the line where lamination of the webs 20 and;49 occurs. With reference to FIGURE 3, the laminated webs 20 and 49 now pass between-a cutting roll 51 having cutting blades 52 and a back-up roll 53. The blades 52 cut completely through the conductive material web 49 but preferably do not cut into the web 20. The blades 52 cut the web 49 into a plurality of series of patterns 25 and 30 best shown in the portion marked D in FIGURE 5. With reference again to FIGURE 3, there is shown a roll 54 comprised of a composite web 55 having a web 37 with a full-gum or continuous coating of pressure sensitive adhesive 38 and a release liner 56 releasably adhered to the adhesive 38 on the web 37. The release liner 56 is separated from the web 37 and the web 37 passes about a sandpaper roll 57. From there the web 37 passes between a pattern roll 58 and a back-up roll 59 where mask patterns 39 are applied onto the adhesive 38 to render the adhesive 38 non-tacky at the mask patterns 39 to provide longitudinally recurring adhesive patterns 38' (FIGURE 1). Masking material from a fountain 60 is applied to the pattern roll 58. The masking material of which the patterns 23 and 39 are comprised is a commercially available printable adhesive deadener such as sold under the name "Aqua Superadhesive Deadener by Environmental Inks and Coating Corp; Morganton, North Carolina. From there the web 37 passes partially about a roll 61 and through a dryer 62 where the mask patterns 39 are dried or cured. The adhesive 38 is rendered non-tacky at the mask patterns 39. From there the webs 20, 49 and 37 pass between laminating rolls 63 and 64.

FIGURE 5 shows that lamination occurs along line E where the web 37 meets the web 49. When thus laminated, each adhesive pattern 21' registers only with an overlying conductor spiral 25 and each adhesive pattern 38' registers only with an underlying conductor spiral 30.

The webs 20, 37 and 49 pass successively partially about rolls 65 and 66 and from there the web 37 delaminates from the web 20 and passes partially about a roll 67. At the place of delamination, the web 49 separates into two webs of conductor spirals 25 and 30. As shown in FIGURE 6, delamination occurs along the line marked F. When delamination occurs, the conductor spirals 30 adhere to the adhesive patterns 38' on the web 37, and the conductor spirals 25 adhere to the adhesive patterns 21' on the web 20.

Thus, the conductor spirals 30 extend in one web and the spirals 25 extend in another web. The web 20 passes partially about rolls 68, 69 and 70 and from there pass between an adhesive coating roll 71 and a back-up roll 72.

Adhesive 29 from a fountain 73 is applied to the roll 71 which in turn applies a uniform or continuous coating of adhesive 29 to the web 20 and over conductive spirals 25.

The portion marked G in FIGURE 6 shows the portion of the web 20 and conductor spirals 25 between the spaced rolls 66 and 72. The portion marked H shows the portion of the web 20 between the spaced rolls 72 and 74. With reference to FIGURE 3, the web 20 passes through a dryer 75 where the'adhesive 29 is dried. A plurality, specifically two laterally spaced dialectric webs 28a and 28b wound in rolls 76 and 77 are laminated to the web 20 as the webs 20, 28a and 28b pass between the rolls 74 and 74'. This laminating occurs along reference line I indicated in FIGURE 6. With reference to FIGURE 3, the web 20 with the conductor spirals 25 and the dialectric webs 28a and 28b pass about rolls 78 and 79 and pass between an adhesive applicator roll 80 and a back-up roll 81. The roll 80 applies adhesive 29' received from a fountain 83 to the webs 28a and 28b and to the portions of the web 20 not covered thereby. From there, the webs 20, 28a and 28b pass through a dryer 84 and partially about a roll 85.

The web 37 which had been separated from the web 20 is laminated at the nip of laminating rolls 86 and 87 along a line marked J in FIGURE 7 to provide a composite tag web generally indicated at 88. The webs 20, 28a, 28b and 37 are laminated between rolls 86 and 87 after the conductor spirals 30 have been shifted longitudinally with respect to the conductor spirals 25 so that each conductor spiral 30 is aligned or registered with an underlying conductor spiral 25.

The shifting can be equal to the pitch of one conductor spiral pattern as indicated at p (FIGURE 9) plus the width w of one conductor, or by odd multiples of the pitch p plus the width w of one conductor. Thus, each pair of conductor spirals 25 and 30 is capable of making a resonant circuit detectable by an appropriate article surveillance circuit.

FIGURE 8 shows the web 20 and the web 37 rotated apart by 1800. FIGURE 9 shows the web 20 and the web 37 rotated apart by 1800 and as having been shifted with respect to each other so that the conductor spirals 25 and 30 are aligned. As best shown in FIGURE 10, the dialectric 28a terminates short of stakes 90 resulting from the staking operation. By this arrangement the stakes 90 do not pass through the dielectric 28a (or 28b). FIGURE 10 shows the conductor spirals 25 and 30 substantially entirely overlapped or aligned with each other, except as indicated at 35 for the conductor spiral 25 and as indicated at 33 for the conductor spiral 30. Each circuit is completed by staking the conductor bars 27 and 32 to each other as indicated at 90 or by other suitable means. The staking 90 is performed by four spiked wheels 89 which make four stake lines 90 in the composite web 88. The spiked wheels 89 pierce through the conductor bars 27 and 32 and thus bring the conductor bars 27 and 32 into electrically coupled relationship. The web composite 88 is slit into a plurality of narrow webs 91 and 92 by slitter knife 93 and excess material 94 is trimmed- by slitter knives 95. The webs 91 and 92 are next cut through up to but not into the release liner 24 by knives on a cutter roll 96, unless it is desired to cut the tags T into separated tags in which event the web 88 is completely severed transversely. As shown, the webs 91 and 92 continue on and pass about respective rolls 97 and 98 and are wound into rolls 99 and 100. As shown in FIGURE 7, the staking 90 takes place along a line marked R and the slitting takes place along a line marked L.

The sheet 37T, the dialectric 28T, the sheet 20T and the sheet 24T are respectively provided by cutting the web 37, the web 28a (or 28b), the web 20 and the web 24.

FIGURE 11 is essentially a duplicate of a portion of FIGURE 3, but a pair of coating and drying stations generally indicated at 111 and 112 where respective coatings 113 and 114 in the form of continuous stripes are printed and dried.

The coating 113 is conductive and is applied directly onto the pressure sensitive adhesive 38 on the web 37. The coatings 114 are wider than the respective coatings 113 which they cover to assure electrical isolation, as best shown in FIGURES 12 and 13. The coatings 114 are composed of a normally non-conductive activatable material. The remainder of the process is the same as the process taught in connection with FIGURES 1 through 10.

With reference to FIGURES 14 and 15, there is shown a fragment of the finished tag 37T' with the coatings 113 and 114 having been severed as the tag 37T' is severed from the tag web as indicated at 113T and 114T respectively. As shown the coating 113T is of constant width and thickness throughout its length and the coating 114T is of constant width and thickness but is wider than the coating 113T. The coating 113T which is conductive is thus electrically isolated from the conductor spiral 30. The coatings 113T and 114T comprise an activatable connection AC which can be activated by subjecting the tag to a high level of energy above that for causing the resonant circuit to be detected at an interrogation zone.

FIGURE 16 is-essentially a duplicate of a portion of FIGURE 3, but a pair of webs 118 and 119 are adhered to the adhesive 38 on the web 37. The webs 118 and 119 are wound onto spaced reels 120 and 121. The webs 118 and 119 pass from the reels 120 and 121 partially about a roll 122. The webs 118 and 119 are spaced apart from each other and from the side edges of the web 37. The webs 118 and 119 are identical in construction, and each includes a thin layer of conductive material 123 such as copper or aluminum on a layer of paper 123', a high temperature, normally non-conductive, activatable, conductor-containing layer 124, and a low temperature, normally non-conductive, activatable, conductor-containing layer 125. The layers 124 and 125 contain conductors such as metal particles or encapsulated carbon. The layer 125 bonds readily when heated, so a drum heater 115 is positioned downstream of the roll 67 (FIGURES 3 and 16) and upstream of the rolls 86 and 87 (FIGURE 3). The heated circuits 30, heat the layer 125 and a bond is formed between the circuits 30 and the layer 125. Rolls 116 and 117 (FIGURE 16) guide the web 37 about the drum heater 115. The heating of the layer 125 has some tendency to break down the normally non-conductive nature of the layer 125, but this is not serious because the layer 124 is not broken down or activated by heat from the drum heater 115.

With reference to FIGURES 19 and-20, there is shown a fragment of a finished tag 37T" with the webs 118 and 119 having been severed so as to be coextensive with the tag 37T" and is indicated at 118T. The web strip-or stripe 118T includes the paper layer 123', the conductive layer or conductor 123 and the normally non-conductive layers 124 and 125. The layers 123, 124 and 125 are shown to be of the same width and comprise an activatable connection AC. Both coatings 124 and 125 electrically isolate the conductor 123 form the conductor spiral 30. In other respects the tag 37T" is identical to the tag 37T and is made by the same process as depicted for example in FIGURE 3.

The embodiment of FIGURE 21 is identical to the embodiment of FIGURES 16 through 20 except that instead of the webs 118 and 119 there are a pair of webs comprised of flat bands, one of which is shown in FIGURE 21 and is depicted at 118'. The band 118' is comprised of a web or band conductor 126 of a conductive material such as copper enclosed in a thin coating of a non-conductive material 127.

The band 118' comprises an activatable connection AC. As seen in FIGURE 21, the upper surface of the coating 127 electrically isolates the conductor 126 from the conductor spiral 30. The band 118' is processed according to one specific embodiment, by starting with coated motor winding wire, Specification No. 8046 obtained from the Belden Company, Geneva, Illinois 60134 U.S.A. and having a diameter of about 0.004 inch with an insulating coating of about 0.0005, flattening the wire between a pair of rolls into a thin band having a thickness of 0.0006 inch. Thus processed, the insulating coating is weakened to a degree which breaks down when the resulting tag is subjected to a sufficiently high energy level signal. The coating 118' is thus termed a "breakdown coating n because it acts as an insulator when the tag is subjected to an interrogation signal at a first energy level but no longer acts as an electrical insulator when subjected to a sufficently higher energy level signal. The conductor 126 accordingly acts to short out the inductor 30 at the higher energy level signal.

The embodiments depicted in FIGURES 11 through 20 and described in connection therewith enable the tag 37T' or 37T" to be detected in an interrogation zone when subjected to a radio frequency signal at or near the resonant frequency of the resonant circuit. By sufficiently increasing the energy level of the signal, the normally non-conductive coating 114 (or 114T), or 124 and 125 becomes conductive to alter the response of the resonant circuit. This is accomplished in a specific embodiment by using a normally non-conductive coating to provide an open short-circuit between different portions of the conductor spiral 30.

When the tag is subjected to a high level of energy, in the embodiments of FIGURES 11 through 15, and 16 through 20 the normally non-conductive coating becomes conductive and shorts out the inductor. Thus, the resonant circuit is no longer able to resonate at the proper frequency and is..unable to be detected by the receiver in the interrogation zone.

While the illustrated embodiments disclose the activatable connection AC provided by an additional conductor as extending across all the turns of the conductor spiral 30 and by a normally non-conductive material or breakdown insulation electrically isolating the conductor from the conductor spiral 30 and also extending across all of the turns of the conductor spiral 30, the invention is not to be considered limited thereby.

By way of example, not limitation, examples of the various coatings are stated below: I. For the embodiment of FIGURES 11 thorough 15 A. Examples of the normally non-conductive coating 114 are: Example 1 Parts by Weight cellulose acetate (C.A.) powder (E-398-3) 60 acetone 300 Mixing procedure: Solvate C.A. powder in acetone with stirring.

C.A./copper dispersion above C.A. solution (16%T.S.) 15 copper 8620 powder 2.5 Mixing procedure: Add copper powder to C.A. solution with adequate stirring to effect a smooth metallic dispersion.

Example 2 acrylvid B-48N (45% in toluene) 30 acetone 20 isopropanol 3 Above solution (25ET.S.) 10 copper 8620 powder 5 Mixing procedure: disperse copper powder into B-48N solution (Percent copper powder is 60-708 on dry weight basis.) B. Examples of the conductive coating 113 are: Example 1 Parts by Weight acryloid B-67 acrylic (45% in naptha) 25 naptha 16 silflake i237 metal powder 42 Mixing procedure: add metal powder to solvent and wet out. Add solvated acrylic and stir well to disperse. Mix or shake well prior to use. (758 to 85% conductive metal on dry weight basis.) Example 2 acryloid NAD-10 t408 in naptha) 10 silflake i237 metal powder 20 Mixing procedure: Add metal powder to acrylic dispersion with stirring.

Example 3 S & V aqueous foil ink OFG 11525 (37%T.S.) 5 silflake i237 metal powder 8 Mixing procedure: Add metal powder to aqueous dispersion slowly with adequate agitation to effect a smooth metallic dispersion.

II. For the embodiment of FIGURES 16 through 20 A. Examples of the low temperature coating 125 are: Example 1 Parts by Weight acryloid NAD-10 dispersion (30% T. Solids) 10 naptha 2 copper 8620 copper powder 5 Mixing procedure: -wet copper powder with Naptha and disperse completely. Add NAD-10 dispersion slowly with stirring. Mix well or shake before use.

Example 2 polyester resin (K-1979) 28 ethanol 10 isopropanol 10 ethyl acetate 20 above polyester solution 10 copper 8620 powder 2.5 Mixing procedure: add copper powder to polyester solution while stirring to effect a smooth metallic dispersion.

(48% copper powder on dry basis) B. Examples of the high temperature coating 124 are: Example 1 cellulose acetate butyrate (C.A.B.)(551-0.2) 40 toluene 115 Ethyl Alcohol 21 Above C.A.B. solution (22.7%) 10 toluene 2 copper 8620 copper powder 5 Mixing procedure: wet copper powder with solvent and add C.A.B. solution with stirring.

Example 2 acryloid B-48N (45% in toluene) 30 acetone 20 isopropanol 3 Above solution (25%T.S.) 10 copper 8620 copper powder 5 (Dry weight basis -- copper is 60-70%) Mixing procedure: add copper powder to above solution with proper agitation to effect a smooth metallic dispersion.

The materials used in the above examples are obtainable from the following suppliers: Acryloid NAD-10, Acryloid B-48N and Acryloid B-67, Rohm & Hass, Philadelphia, Pennsylvania; Cellulose Acetate (E-398-3) and Cellulose Acetate Butyrate (551-0.2), Eastman Chemical Products, Inc., Kingsport, Tennessee; Copper 8620, U.S. Bronze, Flemington, New Jersey; Silflake longitudinal spacing of the resonant circuits assures that electrostatic charge that can prematurely deactivate one resonant circuit in the web cannot arc longitudinally to the other resonant circuits in the web to cause their premature deactivation. Where possible, the same reference character will be used in the embodiment of FIGURES 22 through 25 as in the embodiment of FIGURES 16 through 20 to designate components having the same general construction and function, but increased by 200. It will be appreciated that reference is also made to FIGURES 3, 5 and 6.

With reference initially to FIGURE 22, web 249 of planar, electrically conductive material is cut in patterns of conductor spirals 400 and 401. The cut patterns include lateral pr transverse lines of complete severing 402. The conductor spirals 400 and 401 are generally similar to the conductor spirals 25 and 30, however, inspection of FIGURE 5 will indicate that all conductor spirals 25 and 30 are in very close proximity to each other in the longitudinal direction, being spaced only by knife cuts themselves. In addition, spirals 25 are connected to each other and spirals 30 are connected to each other. In contrast, in the embodiment of FIGURES 22 through 25, only the conductor spirals 400 and 401 between adjacent lines of complete severing 402 are connected to each other. In the method of FIGURES 22 through 25, reference may be had to FIGURE 3 which shows that the conductor spiral webs 20 and 37 are separated as they pass partly about roll 66, thereafter dielectric material webs 28a and 28b are applied, the webs 20 and 37 are.

shifted longitudinally by the pitch of one conductor spiral 400 (or 401) plus the width of one conductor, and thereafter the webs 20 and 37 are re-laminated as they pass between rolls 86 and 87.

As is evident from FIGURE 23, once the web of resonant circuits 401 is stripped away, the resultant web 220 has pairs of resonant circuits 401 that are longitudinally spaced apart. In like manner, the pairs of resonant circuits 400 in the stripped away web (corresponding to the web 37 in FIGURE 3), are also spaced apart longitudinally.

The method of the embodiment of FIGURES 22 through 25, relates to production of deactivatable tags. The illustrated arrangement for deactivating the tags utilizes the arrangement taught in the embodiment of FIGURES 16 through 20 with the exception that the deactivator webs 318 and 319 (corresponding to the deactivator webs 118 and 119 in FIGURE 16 for example), are separated into longitudinally spaced deactivator strips or stripes 318' and 319'. Theseparation is accomplished in accordance with the specific embodiment shown in FIGURE 24, by punching out portions'or holes 407 of the web 238 and the deactivator webs 318 and 319. For this purpose, a diagrammatically illustrated rotary punch 403 and a rotary die 404 are used. The rotary punch 403 has punches 405 and the rotary die 404 has cooperating die holes 406. The resultant holes 407 are wider than the spacing between the resonant circuits. The holes 407 are thus registered with the margins of the longitudinally spaced resonant circuits are shown in FIGURE 25. Thus, static electricity cannot arc between resonant circuits in a longitudinal direction and static electricity cannot arc between deactivator strips 318' (or 319').

The invention of the embodiments of FIGURES 26 through 28, and 29 and 30 has applicability in general to tags with resonant circuits with generally spaced but connected conductors. For example, the invention is useful in the embodiments of FIGURES 1 through 10, 11 through 13, 14 through 20, 21 and 22 through 25. The invention is not limited to applications involving a pair of spiral conductors. It is useful for example in resonant circuits where at least one of the conductors is not a spiral. This type of a circuit is shown for example in U.S. patent 3,913,219. The invention is, however, illustrated with the structure according to the most preferred embodiment of FIGURES 22 through 25.

With reference initially to FIGURE 26, there are illustrated several of the steps in the improved process. It is to be understood that other steps in the process are illustrated in other figures, for example FIGURES 3 and 16.

It is seen in FIGURE 3 that the roll 71 applies a coating-,of adhesive 29 fully across the web 24 and that the roll 80 applies a coating of adhesive 29' fully across the dielectric webs 28a and 28b, but also fully across the exposed portions of the web 24. This means that when the staking occurs as illustrated at 90, the spiked wheels 89 are required to pass through adhesive and also that the spiral conductors are spaced by that adhesive except where the staking occurs. By a construction not shown, and with respect to the embodiments of FIGURES 26 through 28, and 29 and 30, the roll 29 is patterned so it will not apply adhesive to the web 24 except in the path of the dielectric webs 28a and 28b. Roll 80' is identical to the roll 80 except it is patterned to apply adhesive 29' only to the upper sides of the dielectric webs 28a and 28b so that portions 24(1), 24(2) and 24(3) of the web 24 are free of adhesive. From there the web 24 and associated webs 28a and 28b pass through a drier 84 and partly around a roll 85. A fountain 500 has a roll 501 cooperating with a back-up roll 502 to deposit or print a welding material 503 onto the connector portions 400c of spiral conductors 400 in a predetermined repetitive pattern.

It is preferred that two spaced spots of the welding material 503 be applied to each connector portion 400c. As shown, once the welding material 503 has been applied, the web 24 is laminated to the web 37 as they pass between rolls 504 and 505. From there the combined webs 24 and 37 pass-partially around and in contact with a drum heater 506 and from there partially about rolls 507 and 508 to slitters 93 and 95.

From there the tag web 89 can be acted upon by transverse cutter 96 and the resulting narrow webs rolled into individual rolls. The drum heater 506 causes the connector portions 400c and 401c to be welded to each other to make good electrical connection. The expression "welding" as used herein includes what is sometimes referred to as "soldering.

The heater 506 heats the welding material to the temperature where it fuses to the connector portions 400 and 401 to each other but below the temperature where the resonant circuit as degraded or where the activatable connection AC causes deactivation of the resonant circuit. By way of example, not limitation, the welding material fuses at 960C and the breakdown coating 114 for example breaks down at 103 C. The welding material is comprised of 80% by weight of metal alloy and-of 20% by weight of flux and is designated But 52 PRMA & 4 and sold by Multicore Solders Inc., Cantiague Rock Road, Westbury N.Y. 11590. The metal alloy contains 15% tin, 33% lead and. 52% bismuth. The 20% by weight of flux comprises 10.3% resin, 8.48 glycol, 0.38 activators and 1.0% gelling agent.

In an alternative embodiment, the tags can be made as illustrated for example in FIGURES 3 and 16 except instead of applying the welding material 503, the connector portions 400C and 401C are connected by welding using localized heat to bring the temperature of the connector portions 400 and 401 to the melting point. The resulting weld is shown at 509. This can be accomplished for example by a laser beam.

Laser guns 510 illustrated in FIGURE 29 are operated to effect the welds 509.

With reference to the embodiment of FIGURES 31 and 32, FIGURE 31 shows a modification of FIGURE 3 in which a pair of spaced webs 600 and 601 of conductive material such as copper or aluminum are applied to the underside of the web 24. The webs 600 and 601 serve a useful purpose in connection with deactivatable tags in helping prevent their premature deactivation. The webs 600 and 601 can have adhesive thereon. As the webs 600 and 601 pass between roll 43 and a back-up roll 602 the adhesive on the webs 600 and 601 adheres the webs 600 and 601 to the underside of the liner or web 24. The web 24 is continuous and supports the webs 600 and 601 and is thus considered a support or supporting web for the webs 600 and 601. The webs 600 and 601 can be delaminated from a release liner or carrier web 603 as the webs 600 and 601 are drawn from supply roll 60j.

The webs 600 and 601 pass together with web 24 through the entire process and FIGURE 32 shows the underside of the completed tag web or composite tag web 88'. As at least some of the guide rolls used in the process are metal and are electrically grounded, the webs 600 and 601 will prevent the deactivation of the circuits of the embodiments starting with FIGURE 11. In addition, each of the narrow webs 91 and'92 resulting from slitting along centerline 605 will have either web 600 or web 601 adhered thereto so when the tags are printed upon in a properly grounded printer, the web 600 (or 601) will drain off an electrostatic charge and will prevent the deactivator or activatable connection AC from deactivating the associated resonant circuit. The conductive webs 600 and 601 are effective to prevent a destructive electrostatic charge from simultaneously deactivating a multitude of resonant circuits which can result-in the electrostatic charge is not dissipated.

The embodiment of FIGURE 33 accomplishes the same purpose as the embodiment of FIGURES 31 and 32 except that conductive stripes or coatings 606 and 607 are applied to the underside of the web 24 by a roll 608-' which receives coating material form a fountain 608. Examples of conductive coatings are given above in I.B., Examples 1, 2 and 3 and in II.B., Examples 1 and 2. Dryers can be used to dry the coatings 606 and 607 if desired.

In the embodiment of FIGURE 34, a coating roll 609, receiving coating material 610 from a suitable fountain, applies the coating 610 to the underside of the web 24 preferably across its entire width and a coating roll 611, receiving coating material 612 from a suitable fountain, applies the coating material 612 to the web 27 preferably across its entire width. The coating material 610 and 612 can be identical anti-static materials, by way of example, not limitation, a suitable transparent coating material is known as Staticide 3000 concentrate diluted in at least ten parts water for each part of concentrate, by volume. This coating material is sold by ACL, Inc., Elk Grove Village, Illinois 60007 U.S.A. The concentrate is composed of 40% isopropyl alcohol, 59% long chain fatty quaternary ammonium, and 1% floral compounds. It has a boiling point of approximately 800F, a vapor pressure &commat; e 68 F 680F of 35 mmHg., a vapor density of 2.1 compared with air being equal to 1, and a specific gravity of 0.97 compared with water being equal to 1. The diluted concentrate has a boiling point of between 1800F and 2120F, a vapor pressure of approximately 18 mmHg., a vapor density of approximately 2 compared with air being equal to 1, and a specific gravity of 1 compared with water being equal to 1. It is possible that trace amounts of anti-static material have been added to paper and film webs by others in the past, however one embodiment of the present invention is limited to tag webs, having resonant circuits and deactivators, to which anti-static material has been added in sufficient amount and concentration to prevent premature deactivation by interaction between any deactivator and a respective resonant circuit.

It is most preferred to apply both coatings 610 and 612. The tags T are typically completely severed by knives on a cutter roll 96 so if only the coating 612 is applied, electrostatic charge drainage may be insufficient. It is therefore, preferred that at least the supporting web 24, which is continuous, have the coating 610. In that the coating 612 is invisible and does not interfere with printing, the tags T can be printed upon.

The embodiments described.enable-the manufacture of tags with detectable resonant. circuits. economically on a man production basis, wherein -conductors used-in making each - circuit are connected by welding to provide a rel-iable connection. The conductors .can.furthermore be connected without the need for staking. The welding is performed by heating welding material dispersed between adjacent connector portions of the connectors.

Alternatively, the connector portions can be heated and fused locally, as by a laser beam or other suitable contact or non-contact heater.

Many modifications may be made to the examples described.--within the scope of the appended claims.

Claims (4)

1. Method of making tags for use in an electronic article surveillance system, comprising the steps of: providing web having a series of first conductors, providing another web having a series of second conductors, positioning the webs so that the first and second conductors are in adjacent pairs and the first and second conductors of each pair are spaced apart by dielectric r material, and using a laser beam to weld adjacent portions of the first and second conductors of each pair so that each pair provides a detectable resonant circuit.

2. Method of making tags for use in an electronic article surveillance system, comprising the steps of: providing a series of pairs of first and second conductors spaced apart by dielectric material, with each first and second conductor having a connector portion free of dielectric material, and using a laser beam to weld the connector portions of each pair of each other to provide a series of detectable resonant circuits.

3. Method of making tags for use in an electronic article surveillance system, comprising the steps of: providing a series of pairs of first and second conductors spaced apart by dielectric material and adhesively attached, with each first and second conductors having a connector portion free of dielectric material and free of adhesive, and welding the connector portions to each other to provide a series of detectable resonant circuits.

4. Method of making tags for use in an electronic article surveillance system, comprising the steps of; providing a web having a series of first conductors, providing another web having a series of second conductors, wherein at least one of the conductors is a spiral conductor, depositing- welding material on each conductor of one of said series, positioning a deactivator adjacent ona conductor of one of said series, wherein the deactivator includes heat activatable material rendered conductive by the application of heat, positioning the webs so that the first and second conductors are in adjacent pairs spaced apart by dielectric material to provide a tag web, and applying heat to the tag web at a temperature high enough to cause the welding material to weld the conductors to each other to provide a detectable resonant circuit but low enough to prevent the activatable material from being rendered conductive.