NL1002150C2 - Deactivation system with improved reliability. - Google Patents

Description

Deactivation system with improved reliability.

Disposable RF> theft detection labels, called adhesive labels or adhesive labels, are disabled during the checkout process at a checkout using a deactivator called deactivator.

5 Deactivatable item monitoring labels are known. For example, in U.S. such a label is described in Checkpoint patent 4,567,573. It consists of a metal coil, printed (etched) on a plastic foil, and two capacitor plates on either side of this foil, connected to both sides of the coil.

The coil and the capacitor formed in this way form a resonant circuit. When the label is in a magnetic alternating field, for example, between the antennas of a shoplifting detection system, placed at the exit of a shop, when the frequency of that alternating field coincides with the resonant frequency of the label, the label will result from the resonance effect to send back a signal.

A weakening is provided in the capacitor part where overtopping occurs between these plates at a relatively low voltage between the capacitor plates. The consequence of this is that a permanent short circuit is left behind, so that the label in question no longer shows electrical resonance, no longer transmits a signal in the alternating magnetic field, and is thus deactivated.

This category of labels has been used for quite some time, whereby the label is affixed in the store to the object to be protected, or has already been applied in the article or in the packaging by the manufacturer or the packager of the article. After the product is sold, the label is deactivated, so that no alarm occurs during the passage of the buyer with the product concerned through the exit of the store.

A method of making a label deactivatable is known from U.S. Fritz Pichl patent 5,187,466.

Deactivating devices are known from applicant's European patents 0439237 and 0478092.

There may be a difference between the detection range and the deactivation bite 0 C 2 15 0. ' 2 reach from a label to a deactivator.

The detection sensitivity of an deactivator is determined by: 1. the label parameters Q and veff (Effective Volume in 1), which is mainly determined by the physical size of the label; 52. the properties of the detection system in the deactivator, which are limited, among other things, by the limits of legally regulated EMC requirements regarding maximum permissible field strengths.

The deactivation sensitivity determines the maximum detection distance to the 10 antenna.

The deactivation sensitivity is determined by: 1. the label parameter deactivation sensitivity in A / m; 2. the field strength of the deactivation signal, also limited by legal regulations.

15 The deactivation sensitivity determines the maximum deactivation distance to the antenna.

Detection and deactivation sensitivities of labels are standardized in the German directive VDI-4470, concerning detection labels for source protection.

20 The deactivation sensitivity of labels is specified as follows: a label must not deactivate at a field strength of less than 0.9 A / m; may deactivate a label at a field strength between 0.9 and 3 25 A / m; a label must deactivate at a field strength of more than 3 A / m.

The (optional) difference between detection range and deactivation range of a label on a deactivator is mainly determined by production spread in the mass production process with which adhesive labels are made deactivatable and thus in the deactivation sensitivity. Some labels cannot be deactivated at all.

The deactivators described in applicant's European patents 0439237 and 0478092 have separate detection and deactivation circuits.

These deactivators can be set so that the deactivation range of a label with a deactivation sensitivity of 1 A / m overlaps the detection range. As a result, if a label with this deactivation sensitivity is detected, it can also be in the same place 1C 02 150 ..

3 are deactivated.

A non-deactivatable label, which has a deactivation sensitivity of more than 100 A / m, will not even deactivate at a distance of 0 cm from the antenna, although it can be detected at the maximum distance of, for example, 20 cm 5.

A prior art deactivator provides an optical or acoustic indication signal as long as a label is detected and / or a deactivation signal is generated. These signals serve as feedback to the operating personnel.

10 When the signals stop, this means that the deactivator no longer detects a label and that deactivation is complete.

The item with the deactivated label can then be returned to the customer.

The problem now is that checkout staff often think that the deactivator 15 gives a signal that the deactivation has been successful, after which the article is taken out of the field, so that the signal stops, and it is handed over to the customer.

The correct procedure should be:

Keep the item in the field above the deactivation antenna, until the indication signal ceases.

This non-intuitive method is necessary because a label that is no longer in the field cannot be distinguished from a deactivated label by a detector; the presence of "nothing" is difficult to detect.

25 An item on which a label is expected to be absent, because it is defective or has been previously deactivated, does not cause any detection on the deactivator and therefore no indication signal.

If a non-deactivatable label comes within the detection range of an deactivator, the signaling remains active until the label is removed from the field again. In this situation, manual deactivation or removal of the label is then necessary.

This information is often unknown to the checkout staff.

The invention relates to a method of detection in the deactivator, whereby it can distinguish between successful deactivation and an attempt to deactivate a label that cannot be deactivated, after which it is still actively removed from the field of the deactivator.

10 C2150.

4

With the signals obtained from this detection method, optical and / or acoustic indicators can be controlled or they can be presented to, for example, a computer, which in turn can provide information to the personnel, for example by preventing the checkout procedure from being completed.

The optical indicators are for example a red and a green lamp or LED; for example, an acoustic indicator is a piezo beeper that can display tones of different heights and rhythms.

The method of detection that can distinguish between an un-activated label that is manually removed from the field and a label deactivated by the deactivation signal (burst) is based on the decay rate (gradient) of the label signal before and after the burst.

By detecting in a narrow time slot immediately after the burst, the discrimination can be further improved.

The maximum speed at which a label can move through the field is limited by the arm movements of the operating personnel; in practice no more than 2 m / s. A detection range of 20 cm is then completed in at least 100 ms.

20 A detection cycle (sweep frequency period) lasts 7 ms. In 100 ms these are therefore 14 sweeps. The rate of decrease of the detection signal is then about 7% per sweep. With successful deactivation, this decrease rate can be up to 100% per sweep. In the last detection sweep before the burst, the label signal is 100%, in the first 25 sweep after the burst it is 0%.

The essence of the invention resides in exploiting the difference in these decrease rates.

This makes it possible with a reliability of more than 90% to detect whether a label has been deactivated or whether it has been manually removed from the field.

The practical implementation takes place, for example, in the following manner:

Red: Lit during detection. Normally flashes for a very short time (50 to 35 ms), because a label is deactivated immediately after it is detected. The burn time of red is reset by turning on the green lamp. This is necessary because of the slowness of the detection system.

If the green signal does not come, (non-deactivatable label or 10 02 150.

5 deactivation sensitivity too low) then the burn time of red is stretched, after the label has been removed, by the time (3s) that would normally light the green lamp.

The red lamp is therefore lit as long as there is a label in the field, and three more 5 seconds after this (not deactivated) label has been manually removed from the field. The green lamp will then remain off. The 3s burn time is a choice.

Green: Lights up immediately after successful deactivation. The green signal also turns off the red lamp. The burn time is determined with a timer 10 (eg 3s).

If the deactivation is unsuccessful, the green lamp does not go on.

Reset: If the label is removed during the burning time of the red or green lamp and a label is added again in the field, the burning time is shortened and the cycle starts again.

15 Beeper: A beep will sound for as long as the red light is on during detection. If it is a non-deactivatable label, the beeper may emit an intermittent beep during the time the red lamp is lit after the label has been removed.

The moment the green lamp comes on, the pitch changes to indicate that a successful deactivation has taken place.

As a result, the cashier staff are also alerted to the process flow without looking at the lamps.

1 0 02 1 50 ..

Claims (7)

A detection system in a shoplifting detection tag deactivator, characterized in that the system can distinguish between successful deactivation with the deactivation signal of the deactivator and manually removing a label from which the deactivation has failed. A detection system according to claim 1, characterized in that use is made of the difference in rate of change of the label detection signal level between a successful deactivation and a label manually removed from the field which has not been deactivated. A detection system according to claim 1 or 2, characterized in that it is checked in a narrow time slot immediately after the deactivation signal whether the label detection signal is still present. A detection system according to claim 1, 2 and / or 3, characterized in that one or more optical indicators are controlled with said system. A detection system according to one or more of the preceding claims, characterized in that one or more acoustic indicators, with or without different keys, are controlled with said system. A detection system according to one or more of the preceding claims, characterized in that the said system controls one or more acoustic indicators as well as one or more optical indicators. A detection system according to claim 1 or 2, characterized in that an object is controlled with said system by means of which processing errors are registered and / or the checkout procedure is influenced. 1 0 02 l5Qi ΠΜΓΓυη I DC 1 ncrrcnuc NEWNESS RESEARCH OF INTERNATIONAL TYPE I0ENDFIKAT1E OF THE NATIONAL APPLICATION Applicant's mark o (from the registered __SK / E 46_ Dutch · application no. Miemngseaum 1002150 before 22 January 1996 In dat roe pan Applicant (Name) NV NEDERLANDSCHE APPARATENPABRIEK "NEDAP" Oaajm of wet request for a survey of mtemaionaai type By oe Insanoe for intemaaonaai Research ((SA) to the request for a survey of mama do raai type no. 29 January 1996 SN 27019 NL I. CLASSIFICATION OF THE SUBJECT (for applications of different ctassilieaoes. All dassificaoosymtolan declarations) According to the mtamaoonaie dassificaoa (IRC) Int Cl.6 ·. G 08 B 13/24 II. RESEARCHED FIELDS OF OE TECHNOLOGY Requested minimum documentation Classification system Classifications Int Cl 6 G 08 B Examined documents other than minimum documentation insofar as such documents the area under investigation n included III. 1 i NO EXAMINATION FOR CERTAIN CONCLUSIONS (entries on supplementary sheet) IV. 1_; LACK OF UNIT OF INVENTION (comments on supplement sheet) j = orm PCT / ISA / 201 (a) C8 1994 er