JP2910873B2 - Method for deactivating resonance label and circuit device for executing the method - Google Patents

Abstract

In order to deactivate a resonant tag, a pulse generator circuit (1-4) is provided which is designed to transmit a pulse group comprising a specific number of pulses. In addition or as an alternative, an attenuator (R1), which can be deactivated via a switching device (S1), is provided in the transmission antenna circuit to facilitate the subsequent identification of any post-oscillating, i.e. not yet deactivated tags. <IMAGE>

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for deactivating a resonant label comprising a resonant circuit energized by a transmitter emitting energy in the form of pulses and a circuit arrangement for performing the method.

[0002]

2. Description of the Related Art A method of this kind has already been described in EP-A-287 905.
It became known and actually gained a reputation. However, it must be taken into account that mutually conflicting requirements are imposed on the energy released from the deactivation device. That is, it is required that the highest possible energy be transferred to the label so that the label can be deactivated over as large a distance as possible and that production tolerances do not have to be too small for economic reasons. On the other hand,
There are state legal limits that limit the amount of energy that can be released. These upper limits are also necessary for the required compatibility with the components of the radio frequency protection device. Particularly problematic here are the peak value of the energy released and the input time.

[0003]

It is an object of the present invention to transfer maximum energy to a resonant label with as short an emission time as possible and a low peak value.

[0004]

SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a method for controlling a burst time and a burst pause between bursts.
Released energy in the form of a pulse group energy is continuous over time (burst), thereby the peak value of the individual pulses in the pulse group such that some pulses promotes <br/> constantly deactivated This is solved by a deactivation method adjusted to:

[0005]

The invention is based on measurement and realization. According to that, in a constant alternating magnetic field with a deactivation frequency corresponding to the label, even after a relatively slight train of oscillations,
An equilibrium is achieved between the incident energy and the energy consumed by the heat loss and emission at the label. Subsequent vibration trains emitted from the deactivated antenna no longer increase the probability of deactivation of the resonant label.

[0006] As proposed in EP-A-287 905, instead of processing by one individual pulse,
To process with consecutive pulses in one pulse group,
Each pulse represents an oscillatin stimulation of the resonant circuit determined by the label. that time,
The energy released only slowly from the label is, so to speak, stored and amplified within the label. Thus, when considering a large area, it can be said that the individual pulses are significantly weaker than those considered. Therefore, the possibility of interference by other components is greatly reduced. Therefore, since the individual pulses are weaker than in the conventional method, even if a pulse group consisting of several pulses is used, the energy actually emitted hardly increases as a whole.

In one advantageous embodiment, during bursts
Between is shorter than the burst pause time between the burst. In that case, a certain amount of energy based on the previously emitted pulse group remains on the label that has not been deactivated yet, and in some cases , promotes vibration amplification
As such, it would be possible to select a burst dwell time, ie the time between each two individual pulses (bursts). The duration of the burst is calculated from the Q-factor and the center frequency of the resonance label to be deactivated,
It is also advantageous to provide that it does not exceed 100 microseconds and / or that the dwell time of the burst reaches at least 10 times. Another advantageous specification based on the above findings is that each pulse group contains up to 100 pulses.

[0008] Because several pulses are emitted within one pulse group, the frequency of the pulses can be modulated in successive pulse groups. Thereby, possible manufacturing tolerances can be taken into account.

A circuit arrangement for carrying out the method according to the invention is characterized in that the pulse generation circuit comprises a
Continuous pulse group (burst) throughout burst pause time
And / or an attenuating element is connected to the transmitting antenna, and the attenuating element is switchable from an unattenuated state to its attenuated state by a switching device for each burst, whereby the burst within the group of pulses is reduced . The peak values of the individual pulses or of the individual pulses during the non-attenuated state are characterized in that some pulses are constantly adjusted to promote deactivation. This shows the two features as alternatives, both of which work to solve the same problem. It must be remembered that the pulses emitted according to the invention should have a deactivating effect that can be tested. With the damping circuit provided according to the second feature, it is possible to easily confirm whether the deactivation has been performed. On the other hand, this circuit allows the range of the transmitter to be relatively large.
Thus, with a reasonable cost and high efficiency, it is possible to provide a relatively high instantaneous power to the transmitting antenna at a small average power. In this case, by interrupting or bridging this resistor during transmission, the transmission output is reliably prevented from being absorbed uselessly.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. For example, a pulse repetition frequency of 20 to 30 Hz,
For example, a 25 Hz central timing pulse generator (clock g
enerator) 1 is supplied with power from a power supply unit 15. The power supply unit 15 can include one or more batteries, as implied by the symbols. The power supply unit 15 is provided with a connection terminal 16 and can switch between two power supplies.

The timing pulse generator 1 includes a synchronization coupling circuit (synchronization coupl so that it can synchronize with other devices).
ing) 17 may be provided. The frequency of the timing pulse generator determines the number of transmissions of the deactivation circuit (the number of pulses or bursts emitted per unit time). For this purpose, short continuous gate pulses are generated via stage 2 from the slope of the square transmission voltage of the timing pulse generator 1.

Here, it would be originally possible to use a timing pulse generator 1 having a signal shape other than a square pulse. However, it is advantageous to provide a pulse shaping stage at a later stage. This is because a slope as clear as possible is advantageous for generating a gate pulse in step 2. This stage 2 is a kind of time function element (time func
Option element). This time function element determines the burst time via the time of the square signal produced thereby. The time function element can be formed, for example, as a monoflop which responds to the rising slope of the square signal produced by the timing pulse generator 1.

As mentioned at the outset, the energy delivered to the label is practically valid for a limited time only,
The time of the gate pulse must also be correspondingly limited. The optimum number of pulses per pulse group generally depends on the Q factor of the type of resonance label used in each case.
Labels with a high Q-factor often require more pulses than labels with a low Q-factor before an equilibrium is achieved between the received and emitted energy. Here, as already described in EP-A-285 559, the Q-factor depends on the one hand on the quality of the dielectric of the label and on the other hand on the size of the free-space conductive coating on the inductor winding. I have. The number of pulses per pulse group is Q /
It is expedient to calculate from 2, ie half the Q factor. For example, a label with a coefficient Q = 100 requires about 50 pulses. This is, for example, a pulse repetition frequency of 8 MHz.
At z, this corresponds to a gate pulse time of about 6 microseconds. Thus, the gate pulse duration is up to 100 microseconds, but in most applications can be much smaller, for example, about 50 microseconds. In practice, it has been found that 10 microseconds may be sufficient. These situations can vary depending on the structure and spatial conditions of the label, but can be as low as about
Microseconds) also provided useful results. On the contrary, only one microsecond could be achieved.

A gate pulse emitted from the time function element 2 reaches an input of a gate circuit (AND gate) 3,
The other input is coupled to a pulse train generator 4 which also produces an advantageous continuous square pulse. The gate 3 is opened by a gate pulse of the time function element 2 and transmits a group of pulses emitted from the pulse train generator 4 at a corresponding time (burst time). The gate time is selected as described above to transmit the desired number of pulses.

Thus, it is clear that steps 1 to 4 together constitute an original pulse generating circuit which emits a pulse group or burst. These steps can optionally be replaced by other circuits, for example a high-frequency start-stop pulse generator which is always energized by a time function element. The high-frequency start-stop pulse generator automatically shuts down again after each start and emission of a predetermined number of pulses. However, such pulse generators generally require a certain amount of oscillation time, so the solution described first takes precedence.

As is well known, resonant labels have some manufacturing tolerances associated with them. This should not be too small for fabrication. Therefore, there is some deviation in the natural frequency or resonance frequency of such a label. Therefore, it is advantageous for the pulse train generator 4 itself to have a pulse repetition frequency modulator or to be coupled to an external modulator 14 as described above. On the one hand, it is desirable to calibrate the frequency spectrum just because it is advantageous to adapt to the respective label used. In this case, the step 14 can be provided with an adjustment knob 18 which allows a stepless configuration or switching.

On the other hand, due to the modulation of the pulse frequency,
Two methods are possible. That is, the modulation can be performed within only one pulse group or between bursts. Due to the relatively short burst times, the first method performs poorly, at least unless combined with the second method. As the simplest manufacturing solution, the modulator is formed as a ramp generator. The ramp generator gives the pulse generator 4 a continuous shift in the pulse train frequency. This shift occurs within each pulse group itself, but also between pulse groups. However, as already mentioned, if the modulator 14 is controlled by the output of the amplifier 5 and thus indirectly via the time stage 2 gating pulse,
No frequency adjustment is made during the burst pause between individual pulses. In this case, the length of the ramp reasonably corresponds to several times the time of the gate pulse, and therefore elapses after several burst pulses.

The amplifier 5 has a high power level (high-level stag).
e) Acts as a drive circuit for (power stage) 6; This high power stage obtains the operating voltage via the voltage converter 7. This is described as being connected to the power supply stage 15, similar to the high-frequency transmitter 4.
However, the voltage converter 7 can also have its own power supply when powered by a battery. Next, the signal leaving output stage 6 is supplied to transmitting antennas C, L1.

Due to the relatively low total energy demand, the deactivation circuit can easily be formed as a battery operated device. In each case, it is advantageous to combine the circuit with a conventional barcode scanner 19 or to attach at least one of the two antennas C, L1 and / or L2 described above to the casing of this scanner 19. The scanner 19 can be variously configured, but a flat or vertical scanner integrated into the cashier system is advantageous.

The advantages of such an approach are clear. The scanner 19 simultaneously and automatically deactivates the label when reading the bar code attached to the resonant label. Since the deactivation circuit has a small size (small deactivation energy), it can be easily formed. For example, in the case of a flat scanner, the antenna can be easily mounted on the scanner as an accessory, and in the case of a vertical scanner, it can be appropriately installed in front of the scanner. In some cases, holding the scanner directly on the label ensures an extra large deactivation rate. As a result, the required deactivation energy can be further reduced.

The scanner 19 can be connected to the adapter plug 21 of the above-described circuit device using a plug jack 20. At this time, if it is possible to switch from the battery operation to the main power supply circuit by selecting the power supply, the scanner 19 closes the switch 22 as necessary. With this switch, it is also possible to switch to battery operation as needed.

As shown in FIG. 1, the output of the time function element 2 is connected to another time function element 9 formed as a flip-flop, for example. Time function element 9
Produces a test pulse that is much longer than the pulse time of the gate pulse generated by the time function element 2. This time function element 9 is triggered for this purpose by the falling slope of the gate pulse leaving stage 2. The receiving circuit identifies labels that continue to oscillate (and are thus apparently not yet deactivated). Such a signal arrives via the above-described receiving antenna L2. In order to prevent over-control and destruction of the receiver, a control stage 10 is connected downstream of the receiving antenna. When the high-frequency amplifier 11 is deactivated by the time function element 9, the incoming signal is suitably amplified by this amplifier and sent to the evaluation stage 12. The evaluation stage 12 activates the optical and / or acoustic signaling devices 23, 24 as schematically shown.

It may be desirable to activate the signaling devices 23, 24 at different times. In most cases, it is preferable for the respective signaling device 23 or 24 to generate a warning only if no deactivation has taken place. This is also a standard example. However, it is sometimes desirable that deactivation has been confirmed by activation of signaling devices 23 and / or 24. In this case, it is only necessary to connect the selector switch 25 to the above-described circuit.

Other modes of the signaling devices 23, 24 are also possible, depending on the various logical combinations. For example, information such as “label identification”, “label generates an attenuated echo” (not deactivated), and “label echo suddenly disappears” (deactivated) can be combined. The selector switch 25 can be formed as a switch that can be adjusted to several positions instead of a simple switch as shown.

Finally, as is evident from FIG. 1, during the operation of the receiving circuits L2, 10-12, 23-25, the time function element 9 not only opens and closes one time window, but also this time window. The signal reaches the switching stage S1 via the amplifier 8 (to match the impedance).

The switch stage S1 formed by this reasonably electronic switch causes the attenuation resistor circuit R1 to be switched to the antenna circuit C, L1. Damping resistance circuit R
1 can be formed from only one damping resistor or several elements in the manner described above. The damping resistance circuit R1 greatly reduces the interference factor of the resonance antenna circuit R1 on the receiving circuit. This makes it easier to re-detect an existing label echo via the receiving antenna L2. Therefore, during the gate pulse when a burst is radiated and high energy is supplied to antennas C and L1, switch S1
Is closed, and the damping resistance circuit R1 is bridged.

The timing pulse generator 1 can be synchronized with the deactivation system in order to prevent the influence of a label deactivation system operating nearby by label deactivation. This, on the one hand, can be easily performed via the terminal 17 using a cable. On the other hand,
The necessary synchronization signal can be obtained wirelessly via an existing receiving circuit. The receiving circuit comprises means 26 (FIG. 1) for identifying the signal received by the label echo detection system and producing a synchronization signal based on it for synchronizing the pulse train delivery. In addition, it is desirable not only to synchronize the timing pulse generator 1 with other components via the terminal 17, but also to derive a synchronization signal from the circuit in order to know when a burst pause has occurred.
This can be done by the synchronization output 17 '.

In the embodiment according to FIG. 2, identical functional parts are provided with the same reference symbols as in FIG. In this case, some parts shown in FIG. 1 are omitted. These are portions that do not need to be actually present or are actually present but not shown. In each case, the individual features of the various embodiments can be interchanged or combined with one another.

In this case as well, firstly, the battery operation device is targeted, but the power circuit operation device is also possible. Therefore, the connection with the barcode scanner 19 can also be seen. To simplify the circuit structure, and the antenna C, L
Here, only the antennas C and L are provided so that the antenna can be easily accommodated in the casing of the scanner 19. This antenna operates as either a transmitting antenna or a receiving antenna.

For this purpose, the output of the high power stage 6 and the input of the control stage 10 are controlled by a controlled switch stage S1 '.
Is combined with This switch stage involves the antennas C, L
To either the output of the high power stage 6 or the input of the control stage 10. The control of this switch stage S1 '
Analogous to the switch stage S1 in the time function element 9
, Through the window signal and the amplifier 8. As a result, the circuit arrangement requires less space and is very advantageous compared to known circuits in which such a switching possibility is rather not preferred. The damping resistor R1 is connected as a specific resistance of the control stage 10 and can be bridged by the switch stage S1.
However, the guard could be done in ways other than bridges.

If the label occupies a disadvantageous position in the product relative to the transmitting antenna, for example if it is exactly perpendicular to the antenna, the label receives very little energy from the antenna. To correct this, it is advantageous to provide a large number of at least two transmitting antennas. The two transmitting antennas C 'shown in FIG.
In the case of L1 'and C ", L1", it is preferred that these antennas stand at right angles to each other (due to the phenomenon mentioned at the beginning of this paragraph). Although not generally required, if more than one antenna is provided, they can be distributed at appropriate angles.

In this case, it is important to distribute the output signal of the output stage 6 to the transmitting antennas C ', L1' and C ", L1". This can also be done by a switch stage S1 "associated with the antenna. This switch stage has the function of a multiplexer stage when there are several antennas. However, this multiplexer stage S1".
Are the other switch stages S1 'and S1 associated with the antenna.
Instead of being controlled by the time function element 9 as in 1, it is controlled by the frequency divider 13. The frequency divider 13 again divides the gate pulse emanating from the time function element 2 and supplies a pulse of one pulse group to the antennas C 'and L1' in half the pulse time and the antenna in the other half of the pulse time. C "and L1". In response,
The stage 2 gate pulse is longer than in FIGS.

Here, in order to use independent receiving antennas, it is recommended to provide attenuating elements R1 'and R1 "in the antenna circuits C', L1 'and C", L1 ". It can be bridged for transmission operation via steps S1a, S1b, since the transmission antennas operate sequentially, it is possible not only to energize by the time function element 9, but also to synchronize by means of the frequency divider 13. However, such a measure is not necessary in most cases, and the two antennas C ', L1' and C ", L1" are energized in parallel rather than sequentially by the output of the high power stage. However, this would mean splitting the energy, which could cause problems, hence the multiplexer stage S
The above configuration having a 1 "is preferred. Whether such a configuration with several transmitting antennas not present in the prior art is processed by the above-mentioned burst signal, and the above-mentioned interruptable attenuation configuration R1 , R1 'or R1 "can be advantageously realized regardless of whether they are present. On the other hand, such a multi-antenna configuration is not shown in FIG.
Alternatively, it can be advantageously provided in the configuration according to FIG.

When there are a plurality of antennas, the entire configuration is 1
It would be very advantageous to house it in two casings 27. In this casing 27, only the signaling devices 24 and 23 are outside. Such a casing 27 is densely formed for high frequencies and has at least one inlet opening (and possibly also one outlet opening, as in an airfield baggage X-ray apparatus). This opening can optionally be closed with a lid. The product is then introduced into or discharged from the casing to deactivate the label. In this case, when the casing lid is closed, the deactivation switch can be closed. With the deactivation switch, a deactivation pulse or, as in the present invention,
A pulse group (burst) is generated.

Many modifications are possible within the framework of the present invention. Clearly, for example, step 13 of FIG. 3 provides a synchronizing element that can be substituted by other synchronizing circuits if desired.

To control the switching device S1 'of FIG. 2, it would also be possible to provide an additional time function element controlled by step 2 and synchronized therewith. However, it is simpler to use the time function element 9 to determine the required burst pause anyway.

Another variation relates to a deactivation trigger switch actuated by the casing 27 and the lid. Deactivation need not necessarily be performed with such a switch.
Rather, it is also possible that the deactivation signal always flows in the casing 27. This is especially the case if the casing is formed as a pass-through casing. On the other hand, such a trigger switch is generally preferred even when a small casing 27 is provided.
The trigger switch can be mounted at various locations (not shown). For example, the power supply unit 15
By mounting it on itself, it can be switched on or off centrally or all switch parts can be switched off. In addition, at least a part of the circuit is operated in a standby operation to some extent (for example, a timing pulse generator (c
It is also possible to shut off the lock generator) 1 or the pulse train generator 4), other parts, or just insert a trigger switch between the power supply unit and the timing pulse generator 1. In this case, the gate switch 3 cannot be opened at all. As another possibility, a trigger switch can be inserted between the oscillator 4 and the AND gate 3. At that time, the oscillator 4 can operate freely and is stopped only when desired. Finally, the trigger switch is set to the voltage converter 7
And between the high power stage 6 and the high power stage 6. At that time, when the trigger switch is not operated, the antenna gives a weak signal to energize only the resonance of the label in order to confirm the theft. However, in this case, the switch 25
Circuit 12 with several switch positions corresponding to
It is purposeful to combine with an operation mode switch for the Thereby, when the transmitting antenna emits a weak label identification signal, a “stolen identification signal” can be emitted. On the other hand, only "label deactivated" or "no label deactivation" can be distinguished. As regards the time function element 2, it can be formed as a multivibrator, in particular an unstable multivibrator. However, the time function element 2 can have a counter that counts incoming pulses and forms a gate pulse based on it.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a circuit device for implementing a method of deactivating a resonance label according to a first embodiment of the present invention, particularly for battery operation.

FIG. 2 is a circuit diagram of a simplified alternative configuration showing a second embodiment of the present invention.

FIG. 3 is a modified circuit diagram with at least two antennas illustrating a third embodiment of the present invention.

[Explanation of symbols]

 1-4 pulse generation circuit 9 time function element 12 evaluation circuit 13 synchronization circuit 14 frequency modulation circuit 17, 17 'synchronization terminal (synchronous coupling circuit, terminal) 18 adjustment device (adjustment knob) 19 barcode scanner 25 operation mode switch (selector) Switch) 27 Casing C, L1; C ', L1', C ", L1" Transmitting antenna L2 Antenna (receiving antenna) R1, R1 ', R1 "Attenuating element S1; S1a, S1b Switching device S1" Multiplexing device

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G08B 13/24

Claims (16)

(57) [Claims] 1. A method for deactivating a resonant label comprising a resonant circuit energized by a transmitter emitting energy in the form of pulses, comprising a burst time and a bar.
Released energy in the form of successive pulse groups (bursts) through a burst pause time between strike, whereby the peak value of the individual pulses in the pulse group such that some pulses promotes constantly deactivated It is characterized by being adjusted to. 2. The method of claim 1, wherein the duration of the burst is shorter than the pause between bursts. 3. The duration of the burst is calculated from a Q factor and a center frequency of a resonance label to be deactivated.
The method of claim 1, wherein the time does not exceed 0 microseconds. 4. The burst pause time is at least one.
The deactivation method according to claim 1, wherein the method reaches 0 times. 5. The deactivating method according to claim 1, wherein the frequency of the pulse is modulated in a continuous pulse group. 6. The deactivation method according to claim 1, wherein each pulse group includes a maximum of 100 pulses. 7. The circuit device according to claim 1, further comprising a transmission antenna capable of supplying a pulse from a pulse generation circuit, wherein the pulse generation circuit (1 to 4) has a burst time. And bar
Being formed to emit successive pulses (bursts) throughout the burst pauses between strikes ; and /
Or, the attenuating elements (R1, R1 ', R1 ") are connected to the transmitting antennas (C, L1; C', L1 ', C", L1 "),
The attenuation element is a switching device (S1; S1a, S1b)
Allows each burst to be switched from the unattenuated state to its attenuated state, so that the peak value of an individual pulse within a group of pulses or the peak value of an individual pulse during the unattenuated state is always constant. A circuit device characterized in that it is adjusted to promote deactivation. 8. The circuit device according to claim 7, further comprising a synchronization terminal (17, 17 '). 9. At least two transmitting antennas (C ′,
L1 ', C ", L1") are provided at an angle to each other, and the group of pulses from the pulse generating circuits (1-4) is converted and / or multiplexed by these transmitting antennas (S1 "). C ', L1', C ", L1"), and the multiplexing device (S1 ") includes a pulse generation circuit (1-4).
9. The circuit device according to claim 7, wherein the circuit device is controllable by a synchronization circuit connected to the control circuit. 10. At least one antenna (C, L)
Are provided for transmission and reception, and the antenna (C, L) can be switched from the transmission mode to the reception mode by the time function element (9) synchronized with the pulse generation circuits (1 to 4). The circuit device according to claim 7, 8 or 9, wherein 11. The frequency modulation circuit (14) is connected to a circuit element (4) of a pulse generation circuit (1-4) for emitting a pulse group to change the frequency of the pulse group, and a frequency modulation circuit. The circuit device according to claim 7, wherein the circuit (14) is provided with an adjusting device (18) for adjusting a frequency spectrum thereof. 12. The battery according to claim 7, further comprising a battery for supplying power.
The circuit device as described. 13. The barcode scanner (19), wherein the antennas (C, L1, L2; C, L) are arranged on the scanner casing. The circuit device according to claim 11. 14. An evaluation circuit (12) provided with an operation mode switch (25), which displays a confirmation when the label is successfully deactivated by selection, and a failure when the deactivation is unsuccessful. The circuit device according to any one of claims 7, 8, 9, 9, 10, 11, 12, or 13, wherein the circuit device can be switched to an alarm. 15. A high-frequency-tight casing (27) having at least one opening as a receptacle for the test specimen, said opening being able to be closed by a lid, said lid being deactivated. A circuit device according to claim 7, wherein the trigger switch is closed. 16. The receiving device is provided with an element capable of recognizing a signal emitted from a label detection device mounted in the vicinity and generating a synchronization signal suitable for synchronizing pulse train transmission based on the signal. Claim 7, Claim 8, Claim 9,
The circuit device according to claim 10, claim 11, claim 12, claim 13, claim 14, or claim 15.