TWI674415B - Detecting device and method thereof - Google Patents

Abstract

A detection device and method. The detection device includes: a first coil, which generates a first magnetic field above the object to be measured; a third coil, which generates a third magnetic field below the object to be measured; a second coil, which is the second The coil generates a second magnetic field; the fourth coil receives the second magnetic field and induces a voltage, and the voltage drives the third coil through the amplifying circuit, wherein the current generated by the first magnetic field and the third magnetic field is In the same direction.

Description

Detection device and method

The disclosure relates to a detection device and method.

The roll-to-roll (R2R) process is used to make electronic products more and more vigorous, such as: flexible printed circuit boards, conductive films, etc. Among them, the conductive film will be coated or printed on the substrate, and the characteristics of the sheet resistance of the conductive film (such as uniformity, conductivity, magnetic permeability, thickness) and defects will directly affect the pros and cons of the subsequent electronic products, so it must be The sheet resistance of the conductive thin film formed by the coating is measured.

The non-contact measurement device must detect the characteristics and defects of the test sample without damaging the test sample. One of the sensing methods of the non-contact detection device is to use the eddy current principle for sensing. Existing detection methods using unilateral eddy current probes are easily affected by the displacement of the object to be measured (e.g. non-static), and when used for detection of large-sized samples, the connection of the probe must be limited by the large-sized mechanism, and it is too long The wires are also easy to be pulled or vibrated by the dynamic machine. Causes measurement error problems, such as errors in resistance values or permeability.

The disclosure relates to a detection device and method.

According to an embodiment of the disclosure, a detection device is proposed. The detection device includes: a first coil, which generates a first magnetic field above the object to be tested; a third coil, which generates a third magnetic field below the object to be measured; a second coil, which The two coils generate a second magnetic field; the fourth coil receives the second magnetic field and induces a voltage, and the voltage drives the third coil through the amplifying circuit, wherein the first magnetic field and the current generated by the third magnetic field For the same direction.

According to an embodiment of the present disclosure, another detection device is proposed. The detection device includes: a first coil group, which generates a main magnetic field above a test object via a main circuit; a second coil group, which passes through a secondary circuit, below the test object via a secondary circuit A secondary magnetic field is generated, wherein the main magnetic field is in the same direction as the current generated by the secondary magnetic field.

According to an embodiment of the present disclosure, another detection method is proposed. The detection method includes the following steps: providing a first alternating current through a first coil group through a main circuit to generate a main magnetic field above the object to be measured; providing a second alternating current passing through a second coil group through a secondary circuit; A secondary magnetic field is generated below the object to be measured, and the main magnetic field is in the same direction as the current generated by the secondary magnetic field.

In order to have a better understanding of the above and other aspects of the present invention, a number of implementation examples are given below, and in conjunction with the accompanying drawings, the detailed description is as follows:

1‧‧‧detection device

101‧‧‧ Iron core

102‧‧‧non-conductive substrate

103‧‧‧DUT

L1‧‧‧ Coil above the first coil

L3‧‧‧Coil under the first coil

L2‧‧‧ Coil on the second set of coils

L4‧‧‧The coil under the second group of coils

Q1, Q2, Q3 ‧‧‧ amplifier

I1, I3‧‧‧ current

104‧‧‧AC to DC Converter

105‧‧‧ Error Amplifier

106‧‧‧Amplitude Voltage Modulator

107‧‧‧ amplifier

108‧‧‧Current sensor

K‧‧‧ reference voltage

201‧‧‧Current Amplifier

202‧‧‧Voltage Gain Adjuster

203‧‧‧Voltage Amplifier

301‧‧‧main circuit

302‧‧‧Sub-circuit

FIG. 1 is a block diagram of an embodiment of the detection device of the disclosure.

FIG. 2 is a schematic circuit diagram of an embodiment of the detection device of the disclosure.

FIG. 3 is a flowchart illustrating an implementation example of the disclosure detection method.

FIG. 4 is a magnetic position simulation diagram of an embodiment of the detection method of the disclosure.

One embodiment of the disclosure uses two sets of upper and lower coils. The first set of upper and lower coils generate a symmetrical magnetic field to reduce the influence of vibration, and the second set of upper and lower coils are used as a signal magnetic coupling to reduce the influence of excessively long serial lines on the coils. The coil disclosed in this disclosure may be an inductor, a circuit board winding, or a coil equivalent inductance L, but it is not limited to these.

Please refer to FIG. 1, which is a schematic diagram illustrating a block diagram of an implementation example of the detection device 1 of the present disclosure. Among them, the object to be measured 103 (eg, a conductive sample, which may be a thin film) is coated or printed on the non-conductive substrate 102. This detection device 1 includes two sets of upper and lower coils, the first group of upper and lower coils are L1 and L3, the first group of upper and lower coils L1 and L3 are flat; the second group of upper and lower coils are L2 and L4, and the second group of upper and lower coils L2 The L4 series is flat. Among them, the first coil L1 and the first coil The upper coil L2 of the two groups may form a first coil group, and the lower coil L3 of the first group and the lower coil L4 of the second group may form a second coil group. The probes (including the coils L1, L3, L2, and L4) of the detection device 1 and the test object 103 are non-contact and will not damage the test object 103.

The upper coil L1 of the first group generates a main magnetic field by an alternating current above the DUT 103, and the lower coil L3 of the first group generates a secondary magnetic field by an AC current below the DUT 103, and the main magnetic field and the secondary magnetic field are above and below the A uniform magnetic field is generated between the coils. The magnetic field lines of the uniform magnetic field are perpendicular to the object to be measured 103, and the uniform magnetic field is an alternating magnetic field, which can offset the measurement error caused by the object 103 due to vibration during detection. This primary magnetic field is symmetrical to the secondary magnetic field. In one embodiment, the cores of the L1, L2, L3, and L4 coils are sheet or columnar. In one embodiment, the L1, L2, L3, and L4 coils may be laterally wound. In the example, the L1, L2, L3, and L4 coils may be plural.

In FIG. 1, the AC-to-DC converter 104, the error amplifier 105, the amplitude voltage modulator 106, and the amplifier 107 form a main circuit 301, which is an exemplary embodiment of the disclosure. The upper coil L1 of the first group and the upper coil L2 of the second group form a positive feedback through the amplifier 107. The amplifier 107 may be composed of two power amplifiers, which feedback each other to form a positive feedback self-oscillation. The two power amplifiers can refer to Q1 in Fig. 2 And Q2, in an implementation example, are formed in pairs. FIG. 2 is a schematic diagram of a circuit diagram of an implementation example of the detection device of the disclosure. Among them, Q1 and Q2 are not limited to only NMOS or PMOS, as long as they can form an amplifier with positive feedback self-oscillation. In an implementation example, Q1 and Q2 are current amplifiers; In another embodiment, Q1 and Q2 are power amplifiers, but not limited to these.

In FIG. 1, the current amplifier 201, the voltage gain adjuster 202, and the voltage amplifier 203 form a sub-circuit 302. The sub-circuit 302 is an amplifying circuit, which is an exemplary embodiment of the disclosure. In one embodiment, the voltage amplifier 203 may be a multi-stage amplifier. The output current of the amplifier 107 drives the coils L1 and L2 to generate an alternating magnetic field through the amplifier 107. A second magnetic field is generated by the upper coil L2 of the second group. After receiving this magnetic field by the lower coil L4 of the second group, a voltage (i.e., the induced voltage) is induced. ); This induced voltage is amplified by the voltage amplifier 203 and the voltage gain adjuster 202 to output a signal to the current amplifier 201. The current amplifier 201 drives the current I3 into the first lower coil L3, and the current amplifier 201 simultaneously drives the current I1 into the first A set of upper coils L1, I1 and I3 currents are in the same direction (that is, they are also clockwise flowing into coils L1 and L3; or currents are also flowing in counterclockwise directions into coils L1 and L3). Please refer to Figure 4.

When the alternating magnetic field (also a uniform magnetic field) between the upper and lower coils L1 and L3 of the first group passes through the test object 103, the test object 103 will induce an eddy current; and the magnitude of the eddy current is the same as that of the test object 103. The characteristics are related. The characteristics of the DUT 103, such as: uniformity, electrical conductivity, magnetic permeability, thickness, and defects are related. In addition, the eddy current induced by the test object 103 will radiate a secondary magnetic field to resist the change of the alternating magnetic field (that is, the primary magnetic field) generated by the first set of upper and lower coils L1 and L3, so the eddy current will be generated. Variety. The change of the secondary magnetic field of the DUT 103 will be converted into the AC current change value of the coil L1 on the first group, and this change value The current sensor 108 connected in series with L1 and L2 is converted into a detection signal output.

The eddy current changes into an AC signal. In one embodiment, this AC signal is sent to the AC-to-DC converter 104 through the output of the amplifier 107 and converted to a DC signal. The error amplifier 105 converts the input reference voltage K and the AC-to-DC converter After the DC signal output from 104 is subtracted, it is transmitted back to the amplifier 107 through the amplitude voltage modulator 106 to form a negative feedback; the output from the amplifier 107, passed through the AC to DC converter 104, enters the error amplifier 105, and then passes through the amplitude voltage modulator 106. The formed negative feedback is a closed-loop circuit; this closed-loop circuit controls the amplitude of the oscillation voltage of the first group of upper and lower coils L1 and L3 to a fixed value, and the magnitude of the reference voltage K is about this fixed value, K is a certain value , And K can be determined according to the test object. When the negative feedback loop reaches a steady state, the AC voltage amplitude of the coil L1 on the first group is a certain value.

FIG. 2 is a schematic circuit diagram of an embodiment of the detection device. The first coil L1 and the second coil L2 (ie, the first coil group) form positive feedback self-oscillation through two amplifiers Q1 and Q2; power The output current of the amplifier (ie, 107 in the first figure) drives the upper coil L1 of the first group and the upper coil L2 of the second group to generate an alternating magnetic field. It is converted into induced voltage. This induced voltage is amplified by the amplifying circuit (for example: amplifier Q3 is amplified, that is, 201 and 203 in the first figure). The output current can cause an alternating current change in the coils above and below the DUT 103; the eddy current induced by the DUT 103 will radiate a secondary magnetic field to resist Resistance to the change of the alternating magnetic field generated by the first set of upper and lower coils L1 and L3. The output of the power amplifier Q1 is sent to the AC-to-DC converter 104 and converted to a DC signal. The error amplifier 105 converts the reference voltage K and the AC-to-DC converter. After the difference of the DC signal output from 104 is subtracted, it is output to the amplifier Q1 through the amplitude-voltage modulator 106 to form a closed loop of negative feedback; the closed-loop control coil L1 oscillates the amplitude of the oscillation voltage at a fixed value, and the negative feedback loop reaches In steady state, the AC voltage amplitude of the coil L1 on the first group is a certain value, and the change of the secondary magnetic field of the object to be measured 103 will be converted into the AC current variation value of the coil L1 on the first group. This change value is detected by the current sensing The converter 108 converts into a detection signal. In one embodiment, Q3 is a current amplifier; in another embodiment, Q3 is a power amplifier; in another embodiment, Q3 is a voltage amplifier; however, it is not limited to these.

According to the disclosure, another detection method is proposed. FIG. 3 is a schematic flowchart of an exemplary implementation of the detection method. Referring to FIG. 3, in step 402, a first alternating current is provided through the main circuit 301, and a main magnetic field is generated above the object to be measured through the first coil groups L1 and L2, and the main magnetic field generates a current I1; in step 404, The secondary circuit 302 provides a second alternating current, and generates a secondary magnetic field under the object to be measured through the second coil groups L3 and L4, and the secondary magnetic field generates a current I2. In step 406, the currents I1 and I2 generated by the primary magnetic field and the secondary magnetic field are the same. (Ie, the same flows into the coils L1 and L3 in the clockwise direction, respectively; or the current flows into the coils L1 and L3 in the counterclockwise direction, respectively). Please refer to Figure 4.

In one embodiment of the detection method disclosed in the present invention, the main magnetic field and the auxiliary magnetic field generate a uniform magnetic field, and the magnetic field lines of the uniform magnetic field pass through the object 103 to be measured. Straight to the test object 103. The first coil group forms a positive feedback through a feedback method through an amplifier to generate a first magnetic field. The first coil group and the second coil group are driven to generate an alternating magnetic field through the amplifier 107. After the output of the amplifier 107 is converted into a DC signal, it is subtracted from the reference voltage K and transmitted back to the amplifier 107 via the amplitude voltage modulator 106 to form a negative feedback. The negative feedback controls the amplitude of the oscillating voltage of the first coil group to a fixed value, which is determined by the reference voltage K. When the alternating magnetic field of the first coil group passes through the test object 103, the test object 103 will induce an eddy current, and the eddy current will generate a secondary magnetic field. The secondary magnetic field resists the alternating magnetic field and changes the eddy current. The change generated by the eddy current is converted into a detection signal by the current sensor 108.

An embodiment of the present disclosure uses a non-contact eddy current probe located on the object under test. The main circuit 301 provides alternating current, and a magnetic field is generated through the first set of upper and lower coils. The induced current and the amplifier in the main circuit 301 constitute Positive feedback is generated from the oscillating circuit, and the negative feedback control voltage amplitude in the main circuit 301 can reduce the influence of the measurement error caused by the vibration of the coil line: the voltage signal generated by the second set of upper and lower coil induced magnetic fields, After being amplified by the sub-circuit 302, it is fed back to the first set of upper and lower coils for signal magnetic coupling compensation. The magnetic field generated by the main circuit 301 and the sub-circuit 302 has the same direction of induced current. The main circuit 301 and the sub-circuit 302 form a separate circuit. The signals between the separate circuits are transmitted by the AC magnetic field, which reduces the noise interference caused by the excessively long wiring when the upper and lower probes need to bypass the object under test during installation.

The technical content and technical features of this disclosure have been disclosed above, but they are not intended to limit the present invention. However, those with general knowledge in the technical field to which this disclosure belongs should understand that without departing from the spirit and scope of this disclosure as defined by the scope of the attached patent application, the teachings and disclosures of this disclosure can be substituted, changed and modified. For example, many of the devices or structures or method steps disclosed above can be implemented in different methods or replaced with other structures, or a combination of the two methods described above.

The scope of the rights in this case is not limited to the devices, methods or steps of the specific embodiments disclosed above. Those with ordinary knowledge in the technical field to which this disclosure belongs should understand that based on the teaching and disclosure of this disclosure and the disclosure of the machine, device, method or steps, whether existing or future developers, it is substantially the same as the disclosure of the embodiment of this case. Performing substantially the same functions and achieving substantially the same results can also be used in this disclosure. Therefore, the scope of patent application below is intended to cover such machines, devices, methods or steps.

Claims (61)

A detection device includes: a first coil that generates a first magnetic field above a test object; a third coil that generates a third magnetic field below the test object; A second coil that generates a second magnetic field; and a fourth coil that receives the second magnetic field and induces a voltage that drives the third coil through an amplifying circuit, wherein The current generated by the first magnetic field and the third magnetic field are in the same direction; wherein the first magnetic field and the third magnetic field generate a uniform magnetic field. The detection device according to item 1 of the scope of patent application, wherein the magnetic field lines of the uniform magnetic field are perpendicular to the object to be measured. The detection device according to item 1 of the application, wherein the uniform magnetic field is generated between the first coil and the third coil. The detection device according to item 1 of the patent application range, wherein the first coil and the second coil form a positive feedback via an amplifier to generate the second magnetic field. The detection device according to item 4 of the scope of patent application, wherein the amplifier is composed of two power amplifiers, and forms a positive feedback self-oscillation through a feedback method. The detection device according to item 4 of the patent application, wherein the first coil and the second coil are driven by the amplifier to generate an alternating magnetic field. The detection device according to item 1 of the scope of patent application, wherein the amplifying circuit It consists of at least one of a voltage amplifier, a voltage gain adjuster, and a current amplifier. The detection device according to item 7 of the scope of patent application, wherein the voltage amplifier is a multi-stage amplifier. The detection device according to item 4 of the scope of the patent application, wherein the output of the amplifier is converted to a DC signal, and then subtracted from a reference voltage and transmitted back to the amplifier via an amplitude voltage modulator to form a negative feedback. The detection device according to item 9 of the scope of patent application, wherein the negative feedback controls the amplitude of the oscillation voltage of the first coil to a certain value. The detection device according to item 10 of the scope of patent application, wherein the setting value is determined by the reference voltage. The detection device according to item 1 of the scope of patent application, wherein the first coil and the third coil are connected in series with a current sensor. The detection device according to item 1 of the scope of patent application, wherein when an alternating magnetic field between the first coil and the third coil passes the object to be measured, the object to be measured will induce an eddy current. The detection device according to item 13 of the application, wherein the eddy current will generate a secondary magnetic field. The detection device according to item 14 of the scope of the patent application, wherein the secondary magnetic field resists the alternating magnetic field and changes the eddy current. The detection device according to item 15 of the scope of patent application, wherein the change generated by the eddy current is converted into a detection signal by a current sensor. The detection device according to item 13 of the scope of patent application, wherein the magnitude of the eddy current is related to the characteristics of the object to be measured. The inspection device according to item 17 of the scope of patent application, wherein the characteristics of the object to be tested include: electrical conductivity, magnetic permeability, thickness, defects, and uniformity. The detection device according to item 1 of the patent application scope, wherein the first coil generates the first magnetic field above the object to be measured by an AC current. The detection device according to item 1 of the patent application scope, wherein the third coil generates the third magnetic field under the object to be measured by an AC current. The detection device according to item 1 of the scope of patent application, wherein the probe of the detection device and the object to be measured are non-contact. The detection device according to item 1 of the scope of patent application, wherein the first coil is parallel to the third coil. The detection device according to item 1 of the scope of patent application, wherein the second coil is parallel to the fourth coil. The detection device according to item 1 of the scope of the patent application, wherein the cores of the first coil, the second coil, the third coil, and the fourth coil are sheet-shaped or column-shaped. The detection device according to item 1 of the scope of patent application, wherein the first magnetic field is symmetrical to the third magnetic field. The detection device according to item 1 of the scope of patent application, wherein the coils of the first coil, the second coil, the third coil, and the fourth coil are laterally wound. The detection device according to item 1 of the scope of the patent application, wherein the first coil, the second coil, the third coil, and the fourth coil are plural. A detection device includes: a first coil group, which passes through a main circuit to generate a main magnetic field above an object to be measured; and a second coil group, which passes through a secondary circuit A secondary magnetic field is generated below the object to be measured, wherein the primary magnetic field is in the same direction as the current generated by the secondary magnetic field; wherein the primary magnetic field and the secondary magnetic field generate a uniform magnetic field. The detection device according to item 28 of the scope of patent application, wherein the uniform magnetic field passes through the object to be measured. The detection device according to item 28 of the scope of patent application, wherein the magnetic field lines of the uniform magnetic field are perpendicular to the object to be measured. The detection device as described in claim 28, wherein the first coil group forms a positive feedback through an amplifier to generate a first magnetic field. The detection device according to item 31 of the scope of patent application, wherein the amplifier is composed of two power amplifiers, and a positive feedback is formed through a feedback method. The detection device as described in claim 31, wherein the first coil group and the second coil group are driven by the amplifier to generate an alternating magnetic field. The detection device according to item 28 of the patent application, wherein the sub-circuit is composed of a current amplifier, a voltage amplifier, and a voltage gain adjuster, and the output current of the voltage amplifier is positioned above and below the DUT. The upper and lower coils generate AC current changes. The detection device according to item 34 of the patent application scope, wherein the voltage amplifier is a multi-stage amplifier. The detection device according to item 31 of the scope of patent application, wherein the output of the amplifier is converted to a DC signal, and then subtracted from a reference voltage and transmitted back to the amplifier via an amplitude voltage modulator to form a negative feedback. The detection device according to item 36 of the scope of patent application, wherein the negative feedback controls the amplitude of the oscillation voltage of the first coil group to a certain value. The detection device according to item 37 of the scope of patent application, wherein the setting value is determined by the reference voltage. The detection device according to item 28 of the scope of patent application, wherein the first coil group is connected with a current sensor in series. The detection device according to item 28 of the scope of patent application, wherein when an alternating magnetic field of one of the first coil groups passes through the object under test, the object under test will induce an eddy current. The detection device according to item 40 of the application, wherein the eddy current will generate a secondary magnetic field. The detection device according to item 41 of the scope of patent application, wherein the secondary magnetic field resists the alternating magnetic field and changes the eddy current. The detection device according to item 42 of the scope of patent application, wherein the change generated by the eddy current is converted into a detection signal by a current sensor. The detection device according to item 40 of the scope of patent application, wherein the magnitude of the eddy current is related to the characteristics of the object to be measured. The detection device according to item 44 of the scope of patent application, wherein the Characteristics include: electrical conductivity, magnetic permeability, thickness, defects, and uniformity. The detection device according to item 28 of the scope of patent application, wherein the first coil group generates the main magnetic field above the object to be measured by an alternating current. The detection device according to item 28 of the scope of patent application, wherein the second coil group generates the secondary magnetic field under the DUT by an AC current. The detection device according to item 28 of the scope of patent application, wherein the detection device is a non-contact type. The detection device according to item 28 of the patent application, wherein the first coil group is parallel to the second coil group. The detection device according to item 28 of the scope of the patent application, wherein the cores of the first coil group and the second coil group are sheet-shaped or column-shaped. The detection device according to item 28 of the scope of patent application, wherein the primary magnetic field is symmetrical to the secondary magnetic field. The detection device according to item 28 of the scope of patent application, wherein the coils of the first coil group and the second coil group are respectively laterally wound. The detection device according to item 28 of the scope of patent application, wherein the first coil group and the second coil group are plural. A detection method includes: providing a first AC current through a main circuit through a first coil group to generate a main magnetic field above a test object; and providing a second AC current through a secondary circuit through a The second coil group generates a secondary magnetic field below the object to be measured, wherein the primary magnetic field and the secondary magnetic field generate a magnetic field. The current is in the same direction; wherein the primary magnetic field and the secondary magnetic field generate a uniform magnetic field, and the magnetic field lines of the uniform magnetic field pass through the object under test perpendicular to the object under test. The detection method according to item 54 of the patent application scope, wherein the first coil group forms a positive feedback by means of a feedback through an amplifier to generate a first magnetic field. The detection method as described in claim 55, wherein the first coil group and the second coil group are driven by the amplifier to generate an alternating magnetic field. According to the detection method described in claim 55, wherein the output of the amplifier is converted to a DC signal, it is subtracted from a reference voltage and transmitted back to the amplifier via an amplitude voltage modulator to form a negative feedback. The detection method as described in item 57 of the patent application range, wherein the negative feedback controls the amplitude of the oscillation voltage of the first coil group to a certain value, and the certain value is determined by the reference voltage. The detection method according to item 54 of the patent application, wherein when an alternating magnetic field of one of the first coil groups passes through the object to be measured, the object to be measured will induce an eddy current, and the eddy current will generate a secondary magnetic field . The detection method according to item 59 of the patent application scope, wherein the secondary magnetic field resists the alternating magnetic field and changes the eddy current. The detection method according to item 60 of the patent application range, wherein the change generated by the eddy current is converted into a detection signal by a current sensor.