CA2064191C

CA2064191C - Method for tagging articles used in conjunction with an electronic article surveillance system, and tags or labels useful in connection therewith

Info

Publication number: CA2064191C
Application number: CA002064191A
Authority: CA
Inventors: Peter L. Gill; Anthony F. Piccoli
Original assignee: Checkpoint Systems Inc
Current assignee: Checkpoint Systems Inc
Priority date: 1989-10-31
Filing date: 1990-10-04
Publication date: 1996-12-24
Anticipated expiration: 2010-10-04
Also published as: DE69033093T2; DK0774740T3; JP2002197159A; EP0774740B1; EP0541544B1; AU6542690A; MX172162B; JPH05501320A; IE903893A1; NO921564D0; EP0541544A4; FI112553B; ES2133272T3; KR0172100B1; CA2064191A1; WO1991006934A1; ES2194951T3; NZ235685A; ATE234491T1; KR920704248A

Abstract

Electronic article surveillance (EAS) tags (20) are attached to articles of mer-chandise, not at the store (16) using \ equipment (18), but in conjunction with the manufacture (10) of these articles. At that stage, the tags (20) are not detectable by the EAS equipment (18). They are made detectable upon receipt by an EAS-using store (16). For swept frequency RF EAS equipment (18), the tags (20) are initially provided with two capacitors (24, 25) which make the tags (20) resonant at a first frequency not detectable by the store's EAS equipment(18). To activate them, one capacitor (24,25)is disabled, thereby making the tags (20) resonant at a different frequency which is detec-table.

Description

WO 91/0693~ PCr/US90/0~6X8 206@191 21ET~IOD FOR TAGGING ARTICLEB 118E:D IN
CCh~l Uh~ 01~ ~IT~i AN ELECTRONIC ARTICLE
8~RV~TT T ' 8Y8~rEII, AND TAa8 OR I~
~8~!:F~L IN CON2~ECTION '~ K~
Bac~groun~ of the Invention The present invention relates generally 10 to so-called "electronic 2rticle surveillance", and in particular, to a system which involves the use of electronic211y detectable tags or labels which 2re attached to articles of rlerrh~nrl i ~ in order to protect these articles fror~ unauthorized renoval, 15 such as by shoplifting.
For ~nh~nr~e~ security and inventory control, the u6e o~ electronic article surveillance (EAS~ syste~s has become increasingly widespread.
These systems utilize tags or labels which contain 20 an electronic circuit (e.g., a resonant circuit) for interacting with an applied le.g., swept radio-frequency~ electror~2gnetic field. A trans-mitter and arc~-r~nying antenna produce this field, and a nearby receiver and accompanying antenna 25 detect variations in the received field c2used by the presence of a tag. This transrlitting and receiving equipment is positioned at the location or locations where it is desired to detect the unauthorized removal of tag-bearing articles, e.g., 30 at the exit of a retail stDre.
The tags attached to those articles whose relDoval is authorized (e . g ., because these articles have been properly checked out~ are either WO 91/06934 PCI /US901û5688 , .= =~ --- 2 ~ ~0~
physically removed from the articles, or deacti-vated, i.e,~ treated 50 that they become incapable of producing detectable variations in the received field. Othsrwise, these tags will be detacted and 5 an alarm slqnal will be p- cd cc:d by the aquipment.
Commercial ~EAS systems ~s ~generally described above are tvailable from manu~acturers such as Checkpoint Systelos, Inc. of Thorofare, New Jersey, among others.
An important consideration in the use of such E~S systems is the manner in which the detect-able tags or labels are applied to the articles which are to be protected. Some retail stores, for example, wish to have t~gs 2pplied t~ ~11 the 15 articles in their inventory, while others wish to have tags applied only to some of these articles, leaving others sntagged. Likewi~e the selection of the kinds Df mert~hAn~ to be tagged may vary from store to stcre, ancl f ror, time to time within the 20 same store.~ Even within a common rAfamily'r of 6tores, suc~ a6 the ~e31ber stores of a chain, these practices may--and frequently do--vary from one store tD another. This variety r coupled with the ab6ence unt1 now of affy practical technique for 2~ /Ivoiding~local tag ~pplication, has led to the coDImon practice for users of EAS~;ystems to tag articles locally, ~It each EAS equippe store.
}iowever, such Ustore" tagging is time consuming ~nd labor intensive. Also, store tagging 30 is often delegated to p~r,~-a-el who may be limited in traininq~ or inter~st. Ths ~an . - ~ iFe the effectiveness of EAS, which is obviously signifi-cantly c~pen~l~nt upon proper tagging of the articles to be protected.

-3~ PCI/US90/0~688 -2a~lsl In view of all this, theoretical con-sideration has preYiously been given to the possibility of performing the desired tagging of articles at some other point, upstream from the 5 store itself in the distribution chain, such as at the merrhl~n~ e manufacturing stage, or at some intermediate stage of warehousing or distribution.
This theoretical possibility has not found prac-tical realization because of certain formidable 10 obstacles.
Tf detect2ble tags were to be applied to articles of merchandise at their manufacturing stage, then a given product line would have to be processed in two different varieties, one tagged 15 and one not tagged. I~oreover, this segregation would have to be perpetuated throughout the sub-sequent distribution rh~nnl~ls. The reason for this is that many--indeed most--stores do not yet use EAS. These non-EAS using stores would need to be 20 reliably supplied with non-tagged articles; other-wise EAS tags would leave these stores, still attached to the articles being ~;old, and thereby create what is ~o~etimes called "pollution" of the marketplace with EAS tags. Conversely, ~tores 25 which do use EAS would have to be reliably supplied with tagged articles, or their liAS protection would become ineffective.
If, on the other hand, EAS tags were to be applied at an intermediate distribution stage, 30 this would require breaking the bulk packaging which is typically used at those stages, handling the individual articles, and repackaging them in bulk. Furthr ^ e, subsequent segregation of tagged and not-tagged articles would again be 35 required.

WO 91~06934 pCI /~!S90/0~688 2~4~ g I
R~ry o f tb- ~n~ention It is therefore the primary object of the present invention to provide a technique f or pro-tecting articles by means of EAS, without having to 5 apply the n~c~ y detectable tags or labels to these articles at the actual EAS-using stores.
I~t is also an object of the present invention to proYide a tagginy technique which no longer requires a store to individually tag 10 articles which are to be prot~cted by EAS.
It is also an object of the present in-vention to ~provide a tagging technique which can be performed wit~lout having to break the bulk pack-aging of the articles to be protected by EAS.
It is also an object of the present invention to provide a tagging ter~niql~ which can be performed without having to break bulk pack-aglng, while still enabling individu2~ stores to edhere to ~heir individual practlces with regard to 20 which artic~les are to bear EAS detectable tags.
It: is also an object of the present invention to provi~e an EAS tagging ~technique which makes it ~,rm~ E-ry to create two segregated varieties of the ~ame articles, one tagged and one 25 not tagged~,~ upstream from the stores in which these ~rticles are to be retailed. ~ ~
I~t is also an object of the present invention to provide EAS tags or labels which are particularly suitable for the achievement of the 30 above-stated obiects.
These and other ohjects are achieved in nccordance with the present invention by tagging the articles in question, not at the individual EAS
eqlippecl ~itores, as heretofore, but upstream in the 35 aistributiop chain, prefer2bly in conjunction with 4 PC r/US90/05688 .
~ 5 ~ 2 0 6~ 1 9 1 their l~lanufacture. This upstream tagging is performed by means of tags which, at that stage, are not yet detectable by the EAS equipment with which they are ultimately destined to function.

5 Fur~h~ , these tags remain undetectable through the s~hceq~l~nt distribution channel, until they reach that stage at which it is lnherently deter~ined that 211 the so-tagged articles in a given bulk package will be used in an EAS equipped 10 store. This will typically occur at the merchan-dise receiving facility of such an individual store. At that stage, the tags previously attached to the individual arti~les are rendered detectable and the articles with the now-detectable tags 15 attached, are then processed through the store in conventional mannQr.
By procee~l i n~ in accordance with the present invention, the time and labor required for store tagging is eliminated and the reliability of 20 the tagging procedure greatly ~nh~nced. Moreover, it beco~es practical to tag articles in ways which are less visible to the shopper, thereby further improving the protection provided by EAS, and also overcoming possible esthetic as well as functional 25 objections to the use of visible EAS tags.
For further details, reference is Dade to the detailed description which is provided below, taken in conjunction with the accompanying drawings .
Bri-f Do~ription of tb~ Dra~ing~
Figure 1 is a flow diagram of the EAS tag treatment technique embodying the pre6ent inven-tion.

:~ =
W{~ 9l/06934 ~ PCr~!S90~0~8 Figure 2 is a diagrammatic plan view o~ a tag which is useful in implenenting the technigue diagrammed in Figure 1.
Figure 3 is a diagrammatic cross-3ectional Yiew of the tag of Figure 2, taXen along the line 3-3 in Figure 2.
Figure 4 is a diagram of the equivalent circuit of the tag of Figure 2.
In the several figures, like reference number6 denote ~i~ailar structure.
Det~iled Oe~criptio~ cf Prererr~ ~o~iment~
R&ferring to the flow diagram of Figure 1, ~lock 10 represents the manufactur~ng stage of the articles of merchandise uhich are to be sub; ected to the t&chnitaue embodying the present invention.~ ~
~As indicated ~ by block 11, in accordance u$th the invention EAS tags ~re applied to these articles in~ conjunction with their manufacture.
~urther in ~ccordance with the pres~nt invention, ~ ~these tags llre then in a state in which they WDUld not be det~ct~hl~ by the particular type D~ EAS e~u~p~ent with which they Are designed to ultimately ~function.
Block 13 ~e:yl~3CI~S the distribution channel through which these now-tagged articles then pass on their w~y to the retail ~tores.
Block 14 ~yL ~&cnts the ~ n~i-e receiving f cility of one of these retail stores.
3~ Block 15 re~I~ ,ents means, located preferably llt store receiving facility 14, for "activating` the ~AS tags attached to the articles WO 91/06934 PCI`JUS90/05688 206~191 which reach receiving facility 14 fro~ distribution channel 13. By "activating" is meant rendering these tags detectable by the store's EAS equipment.
Block 16 represents the retail store in 5 which the received articles, now be2ring tags which are detectable, are displayed f or retail sale .
Block 17 leple5~ s the means, in store ~6, for deactivating those tags which are attached to articles whose removal from store 16 h2s beco~e 10 authorized, by virtue of the fact that these articles have been properly checked out.
Block 18 represents the EAS detection e~uipment with which the store 16 is equipped and the activity of detecting tags which have not been 15 deactivated at checkout.
In the flow diagram of Figure 1, the manufacturing stage represented by block lo may be entirely conventional, with the sole exception that EAS tags are applied to the merchandise at that 20 stage. However, this application can also be carried out by various, but well known and conven-tional means. For example, an EAS tag may simply be adhesively attached either to each article itself, or to the individual package f or that 25 article. Since these EAS tags are typically similar in external configuratiQn to a thick piece of paper, an inch or two square, and coated on one side with pLe~:auLe sensitive adhesive, guch application may involve nothing more than simply 30 pressing them against a 6urface of the article or its individual packaging. In this regard, the application plOC~ lu~e may be the same as would previously have been performed at the retail store, itself, except that it can now be performed more 35 effici~ntly, and more reliably, by means of the WO 9l/069.~ PC r~rS90/0~6XX
- 8 - 20~419 1 6ame type of ~-~h i h~ry which is convention211y used in manu~acturing to apply other Xinds o tags and labels to 4rticles of merrhAn~
The distribution channel repregented ~y 5 blocX 13 i~n Flgure 1 may be entirely conventional, comprising the various transportation means for moving mer~~hAn~ e to retail stores, the warehouses in which it is stored, etc. While in this channel, tXe mer~h~n~ e iç: typically contained in bulk O packaging, ~ J;uch as cardbo~rd ca6es, each containing multiple units of the individual articles. In accord2nce with the present invention, thsse ca6es now con~2in 2rticles to which not-yet-detectable EAS tags have already been att2ched.
Store receiving facility 14 may also be conventiona~l, in that it comprises the customary unloading~loc~tion and material h;-n~lin7 equipment used by retail stores to ~receive their merch2ndise.
~lowever, in accordance with the inven-20 tion, there is also proYided at this receiving facility 14 the means 15 for activating the heretofore nDt-detectable tags attached to the received merrhAn~; ce . How this is done s described later in this specification.
~Thereafter, this received merch2ndise i5 tre2ted in ~ the same way ~s in any other EAS
eguipped ~tore. That is, it is processed through store 16 in convent0n21 manner, e . 5 . by being displayed ~in the mer~hAn~li se display area and 30 checked out after being elected by customers for purchase. As part of the c~heckout oper2tion, the EAS tags ~re ~ub; ected to deactiY2tl0n by means 17, or ~Iter~ ly are ~ee-ceed by ~A5 deeecelon WO 91/0693~ PC r/~1590/OS6X8 - 9 - 2~6~191 ~quil t 18 upon unauthorized removal. All of this may be a. 1 ~ht?cl in completely conventional manner by completely conventional means.
In particular, the conventional EAS
S equipment 18 used to detect E?~,~; tags which have not been deactivated by means 17 may be of the 80-called swept-frequency RF type. Briefly, this type of equipment transmits a radio f~equency (RF) signal whose fl-~yut~llc~ is periodica~ly varied 10 between, say, 7.4 ana 9.0 MHz. The l~;AS tags for use with this type of equipment comprise an inductor-capacitor (LC) circuit which is resonant within that transmitted band, e.g. at approximately 8 . 2 ~z . The presence of the EAS tag distorts the 15 RF signal and that distortion is detected by a nearby receiver which then gives an alarm.
Such swept-frequency RF EAS-detection equipment is disclosed for example, in U.S. Patents No. 3,500,373, No. 3,810,147 and No. 3,828,337, $~
20 c~nte~e ~f wh;t~ rpo~at~ he~^;~ ~y rcf~r~--o As for the deactivating means 17, this may also operate on a swept-frequency RF basis in the ~ . 4 to 9 . O ~Iz range . Such deactivating means is disclosea, for example, in U.S. Patents No.
25 4,498,076 and No. 4,567~473f "~^ c^r1t~n'~ ;rh n~ )n ~te~ h~re~ hy refer~-~e~
Commercial EAS detecti~n eguipment, as well as deactivation equipment of this swept-frequency RF type is ~vailable from Checkpoint 30 Systems, Inc. of Thorofare, New Jersey, which is also the assignee of the prese~t invention.

WO 91/069?~4 PCI/US9U/0568X
- 10 _ 20641gl Turning now to Figures 2, 3 and 4, these diagra~atically illustrate a kind of: EAS tag ~hich is ~uitable ~for use in the practice of the present invention, in conjunction with EAS eguipn~ent of the 5 ab.,~ ioned s~wept-L,euuen~y RF type.
This tag 20 co:llpriFTe6 a dielectric sub-strate 21, ~.?hich may be n~ade of polyethylene and which bears ~0n each side a cnnt~ tlve pattern 22 ~nd 23, respectively, which may be of i,. l u~ i n~lm ~
As is particularly clearly visible in Figure 2, ~ angular spiral ~portisn ~0f pattern 22 defines an inductor 222, while the sgL-Tare portion in the center defines one plate of a capacitor 24.
The opposite plate of capacitor 24 is defined by 15 the CGL L 5$~ Tlding guare portion~ of pattern 2 3 which is show~ in phantom by broken 1 ines in Figure 2. ~One pla~te of a ~Tecond, smaller cap2ci-tor 25 is defined by the triangular portion at the upper right-hand end of the spiral portion of 20 pattern 22. ~ The spposlte plate of this second capacitor 2~5 is defined by the COLL Y~ ding triangular portiDn of pattern 23 I;hown in phantom by broken lines in Figure 2. Also in pattern 23, a corl~Tlrt jve path 26 (shown in phantoD by broken 25 lines in Figure 2) connectF the plates of capacitors ~24 anTd 25.
~ leferring to Figure 4, the equivalent circuit of ~ the EAS tng 20 ~hown in Figures 2 and 3 is seen to ~consist of a resonant circuit ~ef ined by 30 inductor 22~a and capacitors 24 and~ 2S.
In accordance with the present invention, the tag 20 ~is further provided with two indentation~s, 26a and 27. Indentation 26a is ~orDed in capacitor 24, while indentation 27 i5 35 for~e~ in capacitor 25. ::

WO 9l/06934 PCT/US90/0~68~
2~64191 Given that the EAS equipment 18 in Figure 1, by which tag 20 is to be ultimately detectable, and the de2ctivating equipment 17 by which tag 20 is to be ultimately capable of being 5 deactivated, are both of the swept-frequency RF
type previously mentioned, with trans~itted signals varying in LL ~YUeh~ -Y between 7 . 4 and 9 . 0 MHz, then the values of inductor 23 and capacitors 24 and 25 are ~o chosen that tag 20 initially forms an LC
10 circuit which is resonant at a frequency substan-tially above the 7.4 to 9.0 MHz range, e.g. at a frequency of approximately 18 MHz. The values of inductor 22a and capacitor 24 are further so chosen that, lf capacitor 25 is shorted out, then tag 20 15 forms an LC circuit which is resonant within the 7 . 4 to 9 . 0 MHz range, e . g . at approximately 8.2 MHz.
The abov~ t i oned U . S . P2tents No .
4, 498, 076 and No. 4, 567, 473 disclose the use of 20 indentations such as 26a and 27 provided in capacitors 24 and 25 of tag 20 in order to create a ~hort circuit between the conductive patterns on opposite sides of the dielectric substrate. In these U.S. Patents, the ~horting out is used to 25 deactivate an EAS tag which is designed for use in conjunction with swept-frequency RF EAS equipment.
In the present invention, the indentation 26a in capacitor 24 is provided for the very same purpose, namely for use in ultimately deactivating 30 tag 20 at state 17 in Figure 1. However, in the present invention, the indentation 27 in the other capacitor 25 is provided for the exact opposite purpose, namely for use in activating tag 20, which had previously been not-detectable at the EAS
35 detection stage 18 in Figure 1.

WO 9It06934 ~ ~ Pcrlus9u~056~x ~ - 12 - 20641gl The electronic equipment ~hich is used at activation~stage 15 in Pigure 1 in CDOperation with a tag 20 may be the same as illustrated and de-scribed in~aid U.S. Patents No. 4,4g8,076 and 5 4,567,473, ~with two exceptions.
one exception is that the rL~y ~n~iP~ at which it operates are in a range which i n~lu~lpc the higher~fL~ n.y tof approximately 18 ~Hzj at which tag 20 is initially resonan~. This higher range 10 may be from 16.5 to 19.5 Mffz.
The other exception i5 that this elec-tronic equipment operates at a substanti211y higher power .
By operating in the higher frequency 15 range, the~ eguipment becomes capable o~ shorting out the capacitor 25 via indentation 27. By operating al: high enough power, it becoraes capable of shorting out that ~ame capacitor simultaneously in a plurality of tags 20, Isuch as would be present 20 in a bulk package containing multiple unlts of merchandise articles to which such tags had b~en attached a~ the manufacturing ~nd tag application stage 10, 11 of Figure 1.
~ith~their capacitors 25 80 shorted out, 25 all the ta~gs 20 in the bulk package at recsiving facility 14~ in Figure~ 1 have now become ~ctivated, and have therefore become detectable at stage 18 in co;mpletely~eonventional manner.
MoreoYer, they have now al o become 30 deactivatable at ~tage ~17, also in completely conventional ~anner.
:

9~4 PCT/~!S9n/U~688 Detection at stage 18 would result simply from having such an activated tag 20 present in the 6wept-frequency RF field, whose distortion by that tag i5 then 6ensed by the EAS receiver, causing an 5 alarm.
Deactivation 2t 6tage 17 would result from operating as disclosed in said U.S. Patents No. 4, 498, 076 and 4, 567, 473, namely by shorting out capacitor 24 via its indentation 26. With both o capacitors 24 and 25 (see Figure 4~ so shorted out via respective indentations 26, 27, the tag 20 again becomes undetectable at stage 18 of Figure 1.
As preYiously noted, in order to per~orm the simultaneous activation of the tags attached to 15 all the articles in a bulk package of merrh~n~ise, in accordance with the present invention, it may be n~C~SAry to operate the activating means 15 at higher power than the deactivating means 17, which is typically used to deactivate only one tag at a 20 time. Such higher power may exceed the limit imposed by regulatory agencies such as the United States Federal Co~munications Commission. If that should be the case, then a simple treatment is to provide an enclosure which contains the RF fields 25 produced by the activating means and which is large enough to contain both that means and the EAS tag bearing merrhAn~ , still in its bulk package.
This enclosure may take any of various conventional forms, such as a metal box. The same treatment, 30 namely enclosure of the activating means and the bulk package, may also be used if the frequency range within which the activating signal is transmitted presents a problem in terms of regulatory requirements. That frequency range is 35 prefer2bly ~o chosen that it does not include ~'0 9l/06934 PCr/~JS90/0~6#8 - 14 - 206~191 integral multiple of the fre~uency range within which the deactivation signal is c~lhc~lrntly transmitted. That is tQ forestall the possibility that the aetivating signal may also cause deacti-5 vation of the now-activated tags due to possible Cpurious LeÇ~ r.~ ~e at multiples of the resonant f~ u~lcy of the activated tags.
As previously noted, in order to activate tag 20 by c~anging its re~onant frequency from its 10 initial value (e.g. approximately lB MHz) to its second value (e.g. approximateiy 8.2 ~Hz), capaci-tor 25 is shorted ~at by the application of a sufficientiy strong field at the initial fre~uency.
The total vQltage developed by this applied f ield 15 will appear across the series combination of that capacitor ~25 and capacitor 24 (see Figure 4~ .
However, this total voltage will be distributed between those capacitors in inverse proportion to their plate~ sizes. By maXing capacitor 25 sub-20 stantially ~smaller than capacitor 24, the voltageacross the ~or~er will always be substantially larger than that across the latter. In view of this, and in view of the fact that the indentations in both may be made substantially similar, capaci-25 tor 25 will break down before capacitor 24, as i_desired. ~ ;
~ By pr~c~e~ i n~ i~n accordance with this invention, 1t ic not nec~cs~ry to distinguish, in manufacturing or distribution, ~between products to 3 0 be del ivered to EAS e~u ipped stores and otherc .
Rather, all products~can be tagged, and the EAS
equipped ~tores themselves can then activate those which they~receive~ while other stores need do nothing a ~11.

-WO 91/069~ PCI/~IS90~05688 ' - 15 ~ 2064191 Moreover, these tags can now be applied to the individual articles of merrh~ndi~e in a manner which would not be convenient for store tagging. For example, there would be no problem, at the manufacturing and tag application stage (lo, 11 in Figure 1), to apply EAS tags on the inside of the "bubble pack" or on the inside of a cardboard box containing a particular article. This would have the advantage of concealing the EAS tag, 80 that a shopper would not even know that this particular article is protected.
It will be understood that many other variations are possible, in accordance with the present invention, without departing f rom the inventive concept.
For exa~ple, the invention is not limited to use with articles for sale in retail stores.
Other applications can also benefit, such as book stores, video stores, etc.
As another exa~ple, the initial change in the tag's resonant frequency in order to "activate"
it, need not nec~cs~rily involve an indentation in a capacitor such as indentation 27 shown in Figures 2 and 3. Rather, the tags may be provided with two ~ets of capacitors connected by a fusible link, as disclosed more fully in U.S. Patent No. 3,967,161, c~ tc: arc ;~ 3t~d }~rtt~n ~l ~;e.fLL
ce~ The fusible link may be opened at the activating stage 15 in Figure 1 in order to change the f e:yuency to that which will then be detectable by the store's EAS system. The even higher power which would be res~uired to open such a fusible link i~ then dealt with by enclosure in an RF conf ining box, a6 previously ~CC~cs~d.

Wo 91/06934 ~ PCr/US9~05688 Al~;o, although the preferred application of the invention is to sit~tinn~ in which all the tagged articies in a bulk package are activated ~ nultana~ ely, ~t wlll be understood that the same 5 technique can be utili2ed to activ~te these article~ a~ter they have bsen ~ubdivided into ~maller ~antities, or even one at a time. The other ~Idvantages which ~ri~e fr having ~ppiie~
the tags in cv.~jui.~Lion wlth the ~-n~lf~ct~lre will 10 then still apply.
Accordingly, it is desired that the scope of the present invention be defined only by the `rP'"~:~dc~s,

Claims

- 17 -

1. A method for providing a facility (16) with articles to which devices (20) have been attached which are capable of being detected by article surveillance equipment (18) located at said facility (16), said method comprising:
attaching to said articles, before they reach said facility (16), devices (20) which are not capable of being detected by said equipment, which are capable of being activated to become capable of being so detected:
supplying said articles to said facility (16) and activating (15) said devices (20) upon receipt at said facility (16).

2. The method of claim 1, wherein the attaching is performed in conjunction with the manufacturing (10) of the articles.

3. The method of claim 2, wherein the supplying is in bulk packages containing multiple units of said articles.

4. The method of claim 3, wherein the activating (15) is performed while the articles are still in their bulk packages.

5. The method of claim 2, wherein the devices (20) comprise electronic circuits which are resonant at a first frequency when supplied to said facility (16) and are made resonant at a second frequency by the activating (15) upon receipt at the facility (16).

6. The method of claim 5, wherein the circuits which are resonant at the first frequency are not detectable by said electronic article surveillance equipment (18), but the circuits which are resonant at the second frequency are so detectable.

7. A system for providing a facility (16) with articles to which devices (20) have been attached which are capable of being detected by article surveillance equipment (18), said system comprising:
means for attaching to said articles, before they reach said facility, devices (20) which are not capable of being detected by said equipment, but which are capable of being activated to become capable of being so detected;
means (13) for supplying said articles to said facility (16); and means (15) for activating said devices (20) upon receipt at said facility (16).

8. The system of claim 7, wherein the supplying means includes means for enclosing said articles in bulk packages containing multiple units of said articles with said devices attached.

9. The system of claim 8, wherein the activating means (15) operates on the devices while the articles are still in their bulk packages.

10. The system of claim 7, wherein the devices comprise electronic circuits which are resonant at a first frequency as supplied to said facility, and said activating means (15) comprises means for making said circuits resonant at a second frequency.

11. The system of claim 10, wherein said electronic article surveillance equipment (18) comprises means for detecting said circuits resonant at the second frequency.

12. The system of claim 7, wherein said facility (16) is a retail store and the articles are articles of merchandise for said store.

13. The system of claim 12, wherein the supplying means (13) is the distribution channel for the merchandise for said store.

14. A device (20) for use in the system of claim 10, said device comprising a resonant circuit having two capacitors (24 , 25), whereby said circuit is resonant at said first frequency, and means (15, 26a, 27) for selectively disabling at least one of said capacitors (24, 25) whereby said circuit becomes resonant at said second frequency.

15. The device of claim 14, wherein said capacitors (24, 25) are of different sizes and said disabling means comprises an indentation (26a, 27) in one of said capacitors (24, 25).

16. The device of claim 15, wherein there is also an indentation (26a, 27) in the other one of said capacitors (24, 25).

17. A device (20) for interacting with an electronic article surveillance system (18), said device including a resonant circuit for interacting with an applied radio-frequency field produced by said electronic article surveillance system;
wherein in a first mode of operation said resonant circuit is configured to resonate at a first frequency corresponding to an operative frequency of said electronic article surveillance system;
wherein in a second mode of operation said resonant circuit is configured to resonate at a second frequency different from the operative frequency of said electronic article surveillance system, and is capable of activation for interacting with said electronic article surveillance system; and wherein said resonant circuit includes means for modification from said second mode of operation to said first mode of operation, which is operative at said second frequency.

18. The device of claim 17 wherein said resonant circuit is comprised of etched circuit portions (22, 23) formed on opposing sides of a substrate (21), and wherein said modification means is an indentation (26a, 27) formed at a first selected location along one of said etched circuit portions (22, 23) to define a narrowed space between said etched circuit portions at said first selected location.

19. The device of claim 18 wherein said first location is selected to comprise a series resonant circuit operative at said first frequency following exposure of said device to an applied radio-frequency field at said second frequency.

20. The device of claim 19 wherein said device further comprises means (17) for deactivating said resonant circuit following exposure of said device to an applied radio-frequency field at said first frequency.

21. The device of claim 20 wherein said deactivating means is an indentation formed at a second selected location along one of said etched circuit portions to define a narrowed space between said etched circuit portions at said second selected location.

22. The device of claim 21 wherein said second location is selected to develop a short circuit in said series resonant circuit following exposure of said device to an applied radio-frequency field at said first frequency.

23. The device of claim 22 wherein said device is configured so that the indentation provided at said first location will operate to complete said series resonant circuit before the indentation provided at said second location will operate to develop a short circuit in said series resonant circuit upon exposing said device to an applied radio-frequency field at said second frequency.

24. The device of claim 22 wherein said series resonant circuit includes two capacitor elements, a first of which defines said first location for an indentation and a second of which defines said second location for an indentation, and wherein the first of said capacitor elements is comprised of plate portions which are smaller than plate portions comprising the second of said capacitor elements.