Safety paper detection device for forming multiple magnetic fields
By frequently changing the direction of the magnetic field-generated current in the safety paper detection device and using a microcontroller to control the switching device to switch the current of the transmitting coil, the influence of safety paper orientation and magnetic field direction on detection performance is solved, and stable safety paper detection is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 李明信
- Filing Date
- 2024-10-21
- Publication Date
- 2026-05-12
AI Technical Summary
In existing security paper testing equipment, the testing performance of security paper is easily affected by the orientation of the security paper and the direction of the magnetic field, resulting in large variations in testing performance.
By frequently changing the direction of the magnetic field-generating current in the antenna of the safety paper detection device, and using a microcontroller to control the switching device to switch the current direction of the transmitting coil, multiple alternating magnetic field directions are formed to stabilize the detection performance.
This effectively prevents the decline in detection performance caused by changes in the orientation of the safety paper and the direction of the magnetic field, ensuring stable detection results.
Smart Images
Figure CN122029459A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to electromagnetic (EM) safety paper detection gates for preventing leakage of safety paper, and more specifically, to safety paper detection equipment for detecting amorphous microfilaments inserted into safety paper.
[0002] Throughout this disclosure, the term "security paper detection device" is used consistently, and as used herein, "security paper detection device" refers to a security paper detection gate that senses the presence or absence of security paper when a person carrying security paper passes through the gate, thereby triggering an alarm. Background Technology
[0003] Recently, with the rapid development of enterprises, security measures to prevent the leakage of company documents have been designed. As one such security measure, document security technology using security paper has recently been developed. This security paper refers to paper incorporating amorphous alloys, which generate signals within an alternating magnetic field that can distinguish the properties of the materials.
[0004] The security paper is detected by an electromagnetic sensor at the door. Specifically, when the amorphous alloy within the security paper approaches the alternating magnetic field generated by the sensor, strong Barkhausen noise is generated in the amorphous alloy due to the alternating magnetic field. The presence of the security paper can be identified by detecting the harmonic spectrum of this Barkhausen noise. Such a sensor may include: a transmitting coil that generates the alternating magnetic field; a receiving coil that detects the Barkhausen noise generated in the amorphous alloy by the alternating magnetic field generated by the transmitting coil; and an electronic system that controls the alternating magnetic field generated by the transmitting coil and processes the signal received by the receiving coil. Therefore, since security paper containing amorphous alloy can be detected at a door including such a sensor, leakage of documents printed on the security paper can be prevented.
[0005] Figure 2 A diagram illustrating the generation process of Barkhausen noise, a core principle of security paper detection equipment. When such... Figure 2 An alternating sinusoidal current is applied to B in the middle. Figure 1 When the TX antenna is used, an alternating magnetic field is formed around the TX and RX antennas. If the amorphous metal used as the safety element in the safety paper is present in the alternating magnetic field, a BH curve of the amorphous metal will be formed, such as... Figure 2 As shown in Figure A. At this time, the magnetic domain arrangement within the amorphous metal changes with the alternating magnetic field, producing... Figure 2 The noise shown in C is called Barkhausen noise. Such Barkhausen noise has a spectrum with unique characteristics in the frequency domain, such as... Figure 2As shown in D. The spectrum with unique characteristics is analyzed, and if the spectrum matches that of an amorphous metal used as a safety element, the presence of safety paper is determined, and an alarm is triggered.
[0006] In conventional technology, U.S. Patent No. 5,414,410 discloses: a transmitter for generating two alternating magnetic fields through a single transmitter coil fed with a transmitter signal current; and a receiver for detecting harmonics and intermodulation signals of the alternating magnetic fields through a receiver coil that generates a receiver signal current.
[0007] Furthermore, U.S. Patent No. 5,894,270 relates to an apparatus for monitoring electronic safety elements within an investigation area, comprising: a transmitting device that transmits at least one periodic magnetic field signal to the detection area, wherein the signal causes the safety element to generate a characteristic signal; a receiving device that receives the characteristic signal; and a unit that evaluates the signal received from the receiving device and generates an alarm when the presence of a safety element is determined.
[0008] Furthermore, U.S. Patent No. 5,969,611 relates to an apparatus for monitoring electronic safety components within an investigation area. The apparatus includes: a transmitting device that transmits a transmitted signal into the investigation area, wherein the transmitted signal causes the safety component to emit a characteristic signal; a receiving device that receives the characteristic signal generated by the safety component by means of the transmitted signal; and a unit that evaluates the characteristic signal and generates an alarm when it determines that a safety component is present. The evaluation includes: if the received signal contains a spike signal, removing the spike signal from the received signal.
[0009] Typically, the problem with security paper testing equipment is that the performance of security paper detection varies greatly depending on the shape of the magnetic field formed by the current direction of the TX (transmit) coils used to generate the magnetic field in the antennas installed parallel to each other, and on the orientation of the security paper passing through the security paper testing equipment.
[0010] Existing technical documents
[0011] (Patent Document 0001) U.S. Patent No. 5,414,410
[0012] (Patent Document 0002) U.S. Patent No. 5,894,270
[0013] (Patent Document 0003) U.S. Patent No. 5,969,611 Summary of the Invention Technical issues
[0014] This disclosure aims to provide a security paper detection device that solves the problems of conventional techniques. More specifically, it aims to overcome the problem that the performance of security paper detection varies greatly depending on the shape of the magnetic field formed along the direction of the current in the transmitting coils used to form the magnetic field in antennas mounted parallel to each other, and on the orientation of the security paper passing through the security paper detection device. Technical solutions
[0015] To address the aforementioned issues, embodiments of this disclosure provide a security paper detection device. This device can prevent a decrease in detection performance due to variations in the orientation of the security paper and the direction of the magnetic field by frequently changing the direction of the current input to the antenna of the security paper detection device for generating a magnetic field as the security paper passes through the antenna, thereby applying multiple magnetic field directions to the security paper.
[0016] The security paper detection device according to embodiments of this disclosure includes: a first antenna having a transmitting coil and a receiving coil; a second antenna spaced parallel to the first antenna at a predetermined distance and having a transmitting coil and a receiving coil; a signal generating unit for supplying current to the transmitting coil in the first antenna and the transmitting coil in the second antenna; a microcontroller for controlling the direction of the current in the transmitting coil in the second antenna; and a switching device connected between the transmitting coil in the first antenna and the transmitting coil in the second antenna, so as to be switched by means of the microcontroller. Effects of the present invention
[0017] According to embodiments of this disclosure, the direction of the current used for magnetic field generation in the antenna of the security paper detection device can be frequently changed as the security paper passes through the antenna of the detection device, so that multiple magnetic field directions are applied to the security paper, thereby preventing the degradation of detection performance that varies depending on the orientation of the security paper and the direction of the magnetic field. Attached Figure Description
[0018] Figure 1 This is a diagram illustrating the basic concept of a security paper testing device.
[0019] Figure 2 This is a diagram illustrating the process of Barkhausen noise generation.
[0020] Figure 3 This is a diagram showing an example of safety paper that includes microfilaments as a safety element.
[0021] Figure 4The shape of the magnetic field formed by the direction of the current used for magnetic field generation along the coils of the safety paper detection antennas mounted parallel to each other is shown, as well as an example of the orientation of the safety paper through the antenna.
[0022] Figure 5 The shape of the magnetic field formed by the direction of the current used for magnetic field generation along the coils of the safety paper detection antennas mounted parallel to each other is shown, as well as another example of the orientation of the safety paper through the antenna.
[0023] Figure 6 The shape of the magnetic field formed by the direction of the current used for magnetic field generation along the coils of the safety paper detection antennas mounted parallel to each other is shown, as well as another example of the orientation of the safety paper through the antenna.
[0024] Figure 7 The shape of the magnetic field formed by the direction of the current used for magnetic field generation along the coils of the safety paper detection antennas mounted parallel to each other is shown, as well as another example of the orientation of the safety paper through the antenna.
[0025] Figure 8 This is a circuit block diagram illustrating a safety paper detection device according to an embodiment of the present disclosure.
[0026] Figure 9 This is a circuit block diagram illustrating the main part of the current direction control in a safety paper detection device according to an embodiment of the present disclosure.
[0027] Figure 10 An example of the shape of a magnetic field formed by the change in the direction of the current flowing through the coil of a parallel-mounted safety paper detection antenna, according to an embodiment of the present disclosure, is shown.
[0028] Figure 11 This illustration shows another example of the shape of a magnetic field formed by the change in the direction of the current flowing through the coil of a parallel-mounted safety paper detection antenna, according to an embodiment of this disclosure. Detailed Implementation
[0029] The security paper detection device according to embodiments of this disclosure includes: a first antenna having a transmitting coil and a receiving coil; a second antenna spaced parallel to the first antenna at a predetermined distance and having a transmitting coil and a receiving coil; a signal generating unit for supplying current to the transmitting coil in the first antenna and the transmitting coil in the second antenna; a microcontroller for controlling the direction of the current in the transmitting coil in the second antenna; and a switching device connected between the transmitting coil in the first antenna and the transmitting coil in the second antenna for switching by means of the microcontroller.
[0030] Furthermore, according to an embodiment, the signal generating unit includes a signal generator and a power amplifier connected to the signal generator.
[0031] Furthermore, according to the embodiment, the transmitting coil disposed on the first antenna also includes a first transmitting coil branch line and a second transmitting coil branch line extending outward from the first antenna, the transmitting coil disposed on the second antenna also includes a third transmitting coil branch line and a fourth transmitting coil branch line extending outward from the second antenna, and the switching device includes a plurality of switches, each of the switches being connected between one of the first transmitting coil branch line and the second transmitting coil branch line and one of the third transmitting coil branch line and the fourth transmitting coil branch line.
[0032] Furthermore, according to the embodiment, the power amplifier of the signal generating unit includes a first line and a second line connected to the transmitting coil, and the switching device includes a first switch connected between the first line and the second transmitting coil branch line and the third transmitting coil branch line of the power amplifier, a second switch connected between the second line and the first transmitting coil branch line and the third transmitting coil branch line of the power amplifier, a third switch connected between the first line and the second transmitting coil branch line and the fourth transmitting coil branch line of the power amplifier, and a fourth switch connected between the second line and the first transmitting coil branch line and the fourth transmitting coil branch line of the power amplifier. The microcontroller controls the switches so that the current direction of the transmitting coil disposed in the second antenna is alternately switched.
[0033] Furthermore, according to the embodiment, in the switching device, the second switch and the third switch form a first switch group, and the first switch and the fourth switch form a second switch group, and the first switch group and the second switch group are connected to and controlled by a microcontroller.
[0034] Furthermore, according to the implementation, the inverter is included between one of the first and second switch groups and the microcontroller. Mode of implementing the present invention
[0035] The configuration of the security paper detection device according to this disclosure will be described below based on the accompanying drawings. A preferred embodiment of this disclosure is illustrated in the following description.
[0036] Figure 3 This is a diagram illustrating an example of a security paper 10 including microfilaments 11 as safety elements. Since the paper constituting the security paper 10 is formed in a two-dimensional plane, the microfilaments 11, as safety elements included in the security paper, are distributed along the two-dimensional plane, as shown below. Figure 3 As shown. Furthermore, the antennas of the detection device used to detect the security paper 10 must be mounted parallel to both sides of the passage to allow personnel to pass through. Therefore, the shape of the magnetic field generated by the parallel-mounted antennas is fixed in one direction. Thus, the direction of the magnetic field applied to the microfilament 11 included in the security paper 10 changes depending on the orientation of the security paper 10 via the detection antennas mounted parallel to the passage. Therefore, the intensity of the Barkhausen noise, which is the detection target signal generated from the microfilament 11, also varies. Therefore, the detection rate varies depending on the orientation of the security paper 10 via the antennas of the security paper detection device.
[0037] Figure 4 The shape of the magnetic field formed by the direction of the current used for magnetic field generation along the coils of the safety paper detection antennas mounted parallel to each other is shown, as well as an example of the orientation of the safety paper through the antenna. Figure 5 The shape of the magnetic field formed by the direction of the current used for magnetic field generation along the coils of the safety paper detection antennas mounted parallel to each other is shown, as well as another example of the orientation of the safety paper through the antenna.
[0038] like Figure 4 or Figure 5 As shown, the antennas 20, mounted parallel to each other, are each equipped with a transmitting coil 21 and a receiving coil 22. When currents flowing through the transmitting coils 21 of the parallel antennas are applied in opposite directions, the magnetic fields are formed such that they collide with each other in the middle of the antennas 20 and become parallel to the antennas 20. In this case, when the safety paper 10 passes through in a direction perpendicular to the antennas 20, as... Figure 4 As shown (largely assuming the security paper 10 is carried in a bag like a backpack), the directions of the security paper 10 and the magnetic field are perpendicular to each other. Therefore, the magnetic field does not affect the microfilament 11, which is the security element inside the security paper 10, thus generating almost no Barkhausen noise and making it difficult to detect. On the other hand, when the security paper 10 passes in a direction parallel to the antenna 20, as... Figure 5 As shown (largely assuming the security paper 10 is carried in a handheld briefcase), the security paper 10 and the direction of the magnetic field are parallel to each other. Therefore, the magnetic field effectively affects the microfilament 11, which is the security element inside the security paper 10, thus generating strong Barkhausen noise that is well detected.
[0039] Figure 6 The shape of the magnetic field formed by the direction of the current used for magnetic field generation along the coils of the safety paper detection antennas mounted parallel to each other is shown, as well as another example of the orientation of the safety paper through the antenna. Figure 7 The shape of the magnetic field formed by the direction of the current used for magnetic field generation along the coils of the safety paper detection antennas mounted parallel to each other is shown, as well as another example of the orientation of the safety paper through the antenna.
[0040] As another example, when the current flowing through the transmitting coil 21 of the parallel antenna 20 is applied in the same direction, such as Figure 6 As shown, the magnetic field is formed in a direction perpendicular to antenna 20. In this case, when the safety paper 10 passes through in a direction perpendicular to antenna 20, as... Figure 6 As shown (largely assuming the security paper 10 is carried in a bag like a backpack), the directions of the security paper 10 and the magnetic field are parallel to each other. Therefore, the magnetic field effectively affects the microfilament 11, which is the security element inside the security paper 10, thus generating strong Barkhausen noise that is well detected. On the other hand, when the security paper 10 passes in a direction parallel to the antenna 20, as... Figure 7 As shown (largely assuming the security paper 10 is carried in a handheld briefcase), the security paper 10 and the direction of the magnetic field are perpendicular to each other. Therefore, the magnetic field does not affect the microfilament 11, which is the security element inside the security paper 10, and thus produces almost no Barkhausen noise, making it difficult to detect.
[0041] As described above, depending on the direction of the current applied to the transmitting coil 21 of the antenna 20 and the direction through which the safety paper 10 passes, the safety paper 10 can be either well detected or difficult to detect.
[0042] Figure 8 This is a circuit block diagram illustrating a safety paper detection device according to an embodiment of the present disclosure. Figure 9 This is a circuit block diagram illustrating the main part of the current direction control in a safety paper detection device according to an embodiment of the present disclosure.
[0043] Reference Figure 8 and Figure 9According to an embodiment of the present disclosure, a security paper detection device 100 includes: a first antenna 110 having a transmitting coil 111 and a receiving coil 112; a second antenna 120 parallel to the first antenna 110 and spaced apart by a predetermined distance, having a transmitting coil 121 and a receiving coil 122; a signal generating unit 130 for supplying current to the transmitting coil 111 in the first antenna 110 and the transmitting coil 121 in the second antenna 120; a microcontroller 140 for controlling the direction of the current in the transmitting coil 121 in the second antenna 120; and a switching device 150 connected between the transmitting coil 111 in the first antenna 110 and the transmitting coil 121 in the second antenna 120, so as to be switched by means of the microcontroller 140.
[0044] For example, both the first antenna 110 and the second antenna 120 are arranged in a planar form. A transmitting coil 111 is arranged in a ring shape on the first antenna 110, and a transmitting coil 121 is arranged in a ring shape on the second antenna 120. A signal generating unit 130 is connected to the transmitting coils 111 of the first antenna 110 and 121 of the second antenna 120 via two lines, thereby providing current to the transmitting coils 111 of the first antenna 110 and 121 of the second antenna 120. According to an embodiment, the signal generating unit 130 includes a signal generator 131 and a power amplifier 132 connected to the signal generator 131. When the signal generator 131 generates a current signal, the power amplifier 132 amplifies the current signal and provides current to the transmitting coils 111 of the first antenna 110 and 121 of the second antenna 120. The power amplifier 132 is connected to the transmitting coils 111 of the first antenna 110 and 121 of the second antenna 120 via two lines, forming a closed loop.
[0045] According to an embodiment, the transmitting coil 111 disposed on the first antenna 110 further includes a first transmitting coil branch line 111a and a second transmitting coil branch line 111b extending outward from the first antenna 110. The transmitting coil 121 disposed on the second antenna 120 further includes a third transmitting coil branch line 121a and a fourth transmitting coil branch line 121b extending outward from the second antenna 120. The switching device 150 includes a plurality of switches (e.g., a first switch 151a, a second switch 151b, a third switch 151c, and a fourth switch 151d), each of the switches 151a, 151b, 151c, and 151d being connected between one of the first transmitting coil branch line 111a and the second transmitting coil branch line 111b and one of the third transmitting coil branch line 121a and the fourth transmitting coil branch line 121b. The microcontroller 140 controls the switches 151a, 151b, 151c, and 151d to control the current direction of the transmitting coil 121.
[0046] Furthermore, according to an embodiment, the power amplifier 132 of the signal generating unit 130 includes a first line 132a and a second line 132b connected to the transmitting coils 111 and 121. The switching device 150 includes a first switch 151a connected between the first line 132a and the second transmitting coil branch line 111b and the third transmitting coil branch line 121a of the power amplifier 132; a second switch 151b connected between the second line 132b of the power amplifier 132 and the first transmitting coil branch line 111a and the third transmitting coil branch line 121a; a third switch 151c connected between the first line 132a and the second transmitting coil branch line 111b and the fourth transmitting coil branch line 121b of the power amplifier 132; and a fourth switch 151d connected between the second line 132b of the power amplifier 132 and the first transmitting coil branch line 111a and the fourth transmitting coil branch line 121b. The microcontroller 140 controls switches 151a, 151b, 151c and 151d to alternately switch the current direction of the second transmitting coil 121.
[0047] For example, when microcontroller 140 controls the first switch 151a and the fourth switch 151d to turn on, it controls the second switch 151b and the third switch 151c to turn off. When microcontroller 140 controls the first switch 151a and the fourth switch 151d to turn off, it controls the second switch 151b and the third switch 151c to turn on. Microcontroller 140 frequently executes such control, causing the current direction of the second transmitting coil 121 to be alternately switched.
[0048] Furthermore, according to an embodiment, in the switching device 150, the second switch 151b and the third switch 151c form a first switch group 151, and the first switch 151a and the fourth switch 151d form a second switch group 152. The first switch group 151 and the second switch group 152 are connected to and controlled by the microcontroller 140. The microcontroller 140 can frequently control the first switch group 151 and the second switch group 152, switching them to opposite states, thereby allowing the current direction of the second transmitting coil 121 to be alternately switched. For example, when the microcontroller 140 controls the first switch group 151 to turn on, it controls the second switch group 152 to turn off, and when the microcontroller 140 controls the first switch group 151 to turn off, it controls the second switch group 152 to turn on.
[0049] Furthermore, according to an embodiment, the inverter 151e can be included between one of the first switch group 151 and the second switch group 152 and the microcontroller 140, such that opposite control signals are output to the first switch group 151 and the second switch group 152. For example, as Figure 9 As shown in (a), when inverter 151e is included between the first switch group 151 and the microcontroller 140, opposite control signals for controlling the first switch group 151 and the second switch group 152 can be output via a single output port of the microcontroller 140. Therefore, when the second switch 151b and the third switch 151c of the first switch group 151 are in the ON state, the first switch 151a and the fourth switch 151d of the second switch group 152 are in the OFF state. Figure 9 As shown in (b), when the second switch 151b and the third switch 151c of the first switch group 151 are in the off state, the first switch 151a and the fourth switch 151d of the second switch group 152 are in the on state, thereby controlling the current direction of the second transmitting coil 121 to be switched alternately.
[0050] Figure 10 An example of the shape of a magnetic field formed by the change in the direction of the current flowing through the coil of a parallel-mounted safety paper detection antenna, according to an embodiment of the present disclosure, is shown. Figure 11 This illustration shows another example of the shape of a magnetic field formed by the change in the direction of the current flowing through the coil of a parallel-mounted safety paper detection antenna, according to an embodiment of this disclosure.
[0051] Reference Figure 8 , Figure 9 , Figure 10 and Figure 11The microcontroller 140 frequently controls the switching device 150, causing the direction of the current flowing through the transmitting coil 121 of the second antenna 120 to be the same as or opposite to the direction of the current flowing through the transmitting coil 111 of the first antenna 110. By doing so, Figure 10 and Figure 11 The magnetic fields are formed by frequent interleaving. Therefore, regardless of the orientation of the security paper between the parallel-mounted first antenna 110 and second antenna 120, the magnetic field affects the microfilaments within the security paper. This effectively generates Barkhausen noise, preventing any degradation in the security paper's detection performance.
[0052] As described above, this disclosure is not limited to the specific preferred embodiments described above, and any person skilled in the art can make various modifications without departing from the spirit of the invention as claimed in the claims. Such changes will, of course, fall within the scope of the claims. Industrial applicability
[0053] A security paper detection device can be provided that solves the problem that the performance of security paper detection varies greatly depending on the orientation of the security paper when a person carrying security paper passes through a door.
Claims
1. A security paper testing device, comprising: A first antenna, the first antenna having a transmitting coil and a receiving coil; A second antenna, which is parallel to the first antenna and spaced apart by a predetermined distance, and has a transmitting coil and a receiving coil; A signal generating unit is provided to supply current to the transmitting coil disposed in the first antenna and the transmitting coil disposed in the second antenna; A microcontroller for controlling the direction of current in the transmitting coil disposed in the second antenna; as well as A switching device is connected between a transmitting coil disposed in the first antenna and a transmitting coil disposed in the second antenna, so as to be switched by means of the microcontroller.
2. The safety paper testing device according to claim 1, wherein, The signal generation unit includes a signal generator and a power amplifier connected to the signal generator.
3. The security paper testing device according to claim 1 or 2, wherein, The transmitting coil disposed on the first antenna further includes a first transmitting coil branch line and a second transmitting coil branch line extending outward from the first antenna. The transmitting coil disposed on the second antenna further includes a third transmitting coil branch line and a fourth transmitting coil branch line extending outward from the second antenna. The switching device includes a plurality of switches, each of which is connected between one of the first transmitting coil branch line and the second transmitting coil branch line and one of the third transmitting coil branch line and the fourth transmitting coil branch line.
4. The security paper testing device according to claim 3, wherein, The power amplifier of the signal generating unit includes a first line and a second line connected to the transmitting coil. The switching device includes a first switch connected between the first line of the power amplifier and the branch line of the second transmitting coil and the branch line of the third transmitting coil, a second switch connected between the second line of the power amplifier and the branch line of the first transmitting coil and the branch line of the third transmitting coil, a third switch connected between the first line of the power amplifier and the branch line of the second transmitting coil and the branch line of the fourth transmitting coil, and a fourth switch connected between the second line of the power amplifier and the branch line of the first transmitting coil and the branch line of the fourth transmitting coil. The microcontroller controls the switches to alternately switch the current direction of the transmitting coil disposed in the second antenna.
5. The safety paper testing device according to claim 4, wherein, In the switching device, the second switch and the third switch form a first switch group, and the first switch and the fourth switch form a second switch group, and the first switch group and the second switch group are connected to and controlled by the microcontroller.
6. The security paper testing device according to claim 5, wherein, An inverter is included between the microcontroller and one of the first and second switch groups.