JP2014215082A - Measuring device and measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring device capable of measuring a distance with a conductive or semiconductive object to be measured and a temperature of the object to be measured in non-contact and with high precision.SOLUTION: The measuring device includes: a first coil 21 and a second coil 31 oppositely arranged on an object 10 to be measured; a first conversion circuit 22 for exciting the first coil 21 and outputting a first signal S1 relating to a change of an impedance of the first coil 21; and a second conversion circuit 32 for exciting the second coil 31 and outputting a second signal S2 relating to a change of an impedance of the second coil 31. The respective coils and conversion circuits measure and obtain respective characteristics of the first signal S1 and the second signal S2, and select and use the first coil 21, the first conversion circuit 22, a second coil 31, and the second conversion circuit 32 whose combination is the same level in absolute value. A distance D to the object 10 to be measured from each coil is calculated from the first signal S1 and the second signal S2.

Description

  The present invention detects the distance to the object to be measured and the temperature of the object to be measured from the change in impedance of the coil when the coil excited by alternating current is brought close to the object to be measured which is conductive or semiconductive. The present invention relates to a measuring apparatus and a measuring method.

When a coil excited by an alternating current is brought close to a conductive or semiconductive object to be measured, an eddy current is generated on the surface of the object to be measured by a magnetic flux generated by the coil. This eddy current is generated in a direction that prevents a change in magnetic flux generated by the coil. For this reason, the coil approaching the measurement object is affected by eddy current generated on the surface of the measurement object, and the impedance and inductance change according to the distance from the measurement object. That is, the impedance and inductance of the coil have a correlation with the distance to the object to be measured.
Therefore, by measuring the amount of change (for example, primary measurement amount such as voltage and transmission frequency) related to the impedance change and inductance change of the coil when it is close to the measured object, and analyzing the measurement amount, It is possible to calculate the distance between and the measured object.

In addition, the amount of eddy current flowing through the measured object has a certain correlation with the permeability and conductivity of the measured object, and the permeability and conductivity of the measured object have a certain correlation with the temperature of the measured object. have. In other words, a change in the temperature of the measured object causes a change in eddy current, causing a change in impedance and inductance in a coil at a certain distance from the measured object. That is, the impedance and inductance of the coil have a correlation with the temperature of the measured object.
Therefore, it is also possible to calculate the temperature of the measured object by measuring the amount of change involved in the impedance change or inductance change of the coil at a certain distance from the measured object and analyzing the measured value.

FIG. 7 shows an example of the correlation between the transmission frequency, which is the amount of change involved in the inductance change of the coil, the temperature of the object to be measured, and the distance from the coil to the object to be measured.
In FIG. 7, the vertical axis represents the transmission frequency (unit: Hz), which is the amount of change involved in the inductance change of the coil, and the horizontal axis represents the distance (unit: mm) from the coil to the measured object. Yes. In FIG. 7, a characteristic line f1 shows a correlation between the transmission frequency when the temperature of the measured object is 60 ° C. and the distance from the coil to the measured object. In FIG. 7, a characteristic line f2 indicates the correlation between the transmission frequency when the temperature of the measured object is 30 ° C. and the distance from the coil to the measured object.

In FIG. 7, in the area A1 where the distance from the coil to the object to be measured is within 13 mm, the transmission frequency is different between the case where the temperature of the object to be measured is 60 ° C. and 30 ° C. That is, this area A1 is an area where the temperature of the measured object greatly affects the inductance change of the coil (hereinafter referred to as temperature-dependent area A1). In this temperature-dependent region A1, both the distance to the measurement object and the temperature of the measurement object affect the inductance change of the coil.
Further, in the region A2 where the distance from the coil to the object to be measured exceeds 13 mm, the transmission frequency is almost the same regardless of whether the temperature of the object to be measured is 60 ° C. or 30 ° C. That is, this region A2 is a region (hereinafter, referred to as a temperature-independent region A2) in which the degree of influence of the temperature of the measured object on the coil inductance change is small (has little influence). In this temperature-independent region A2, only the distance to the measurement object affects the coil inductance change.

  In the following Patent Document 1, the distance from the object to be measured and the temperature of the object to be measured are measured in a non-contact manner by utilizing the inductance change of the coil due to the influence of the change of eddy current on the surface of the object to be measured. A measuring device is disclosed.

  In the case of the measuring apparatus disclosed in Patent Document 1, a first coil that is disposed opposite to the object to be measured in the temperature-dependent region A1 in FIG. 7 and is excited by an alternating current, and the first coil that is an alternating current. And a second coil which is arranged opposite to the temperature-independent region A2 of FIG. 7 and is excited by an alternating current with respect to the measurement object. A second transmission circuit for exciting the second coil with an alternating current and outputting a transmission frequency of the second coil; and an arithmetic processing means for performing arithmetic processing on the outputs of the first transmission circuit and the second transmission circuit. ing.

  The arithmetic processing means of the measuring apparatus of Patent Document 1 below is based on the transmission frequency of the second coil having a low temperature dependency and the correlation equation indicating the distance dependency of the transmission frequency, and the distance from the second coil to the object to be measured. Further, the distance from the first coil to the measured object is calculated from the known relative positional relationship between the second coil and the first coil.

  In addition, the arithmetic processing means of the measuring device of Patent Document 1 below is based on the previously calculated distance from the first coil to the object to be measured and the correlation equation indicating the temperature dependence of the transmission frequency of the first coil. Calculate body temperature.

JP 2005-207992 A

  Incidentally, in the temperature-independent region A2 shown in FIG. 7, not only the temperature dependency is reduced, but also the distance dependency is reduced at the same time. Therefore, the distance calculated from the transmission frequency of the second coil disposed in the temperature-independent region A2 cannot obtain sufficient accuracy, and the temperature of the measurement object calculated based on the distance also decreases. . That is, the measuring apparatus disclosed in Patent Document 1 has a problem that the distance to the object to be measured and the temperature of the object to be measured cannot be measured with high accuracy.

  In addition, when the distance to the object to be measured is calculated, the measuring apparatus of Patent Document 1 requires a correlation equation indicating the distance dependency of the transmission frequency, and the calculation processing for calculating the distance to the object to be measured is complicated. There was also a problem of doing.

  In view of this, the present invention provides the distance from the object to be measured and the temperature of the object to be measured from the change in impedance of the coil when the coil excited by the alternating current is brought close to the object to be measured or conductive. It is an object of the present invention to provide a measuring apparatus and a measuring method capable of measuring a high-precision without contact.

The present invention employs the following means in order to solve the above problems.
That is, according to the first aspect of the present invention, there is provided a first coil which is disposed opposite to a conductive or semiconductive object to be measured at a distance and is excited by an alternating current, and the first coil is excited by an alternating current. A first conversion circuit that outputs a first signal that is involved in a change in impedance of the first coil and that depends on the temperature of the object to be measured; and the same as the first coil for the object to be measured And a second coil that is opposed to each other at a distance of 2 mm and is excited by an alternating current, and the second coil is excited by an alternating current and is involved in the impedance change of the second coil and depends on the temperature of the object to be measured A measurement circuit comprising: a second conversion circuit that outputs a second signal that is an amount of change to be received; and an arithmetic processing unit that receives the first signal and the second signal and performs predetermined arithmetic processing on these signals In the equipment is there. The first coil, the first conversion circuit, the second coil, and the second conversion circuit are obtained by measuring characteristics of the first signal and the second signal, respectively. The first coil, the first conversion circuit, the second coil, and the second conversion circuit are selected in a combination in which the polarities in the characteristics of the signal and the second signal are opposite and the absolute values are approximately the same. . Then, the arithmetic processing means calculates a separation distance between the measured object and each coil from the first signal and the second signal.
Here, the absolute value in the characteristics of the first signal and the second signal is about the same, for example, when the absolute value of the first signal is “1”, the absolute value of the second signal is “0.7˜ The one in the range of “1.3”.

  In the measurement apparatus, the first signal related to the impedance change of the first coil close to the measurement object and the second signal related to the impedance change of the second coil close to the measurement object are obtained from each coil. The distance to the object to be measured is calculated. At that time, both the first coil for outputting the first signal and the second coil for outputting the second signal can be brought close to the measured object regardless of the degree of temperature dependence on the measured object. That is, in the measurement apparatus, since the distance can be calculated using a region having a large distance dependency in the first signal and the second signal, the distance from each coil to the measured object can be increased without contact. It becomes possible to measure with high accuracy.

  According to a second aspect of the present invention, in the measurement apparatus according to the first aspect, the arithmetic processing means calculates a deviation ΔS = S1−S2 which is a difference between the first signal S1 and the second signal S2, and The temperature t of the measured object is calculated from the correlation between the deviation ΔS and the temperature t of the measured object and the correlation between the deviation ΔS and the previously calculated separation distance.

  In the measurement apparatus, the deviation ΔS between the first signal S1 and the second signal S2 is a linear function of the temperature t of the measured object, as shown on the right side of the later-described equation (3), and exhibits linearity. That is, the deviation ΔS and the temperature t of the object to be measured have a correlation shown in the following equation (3).

  A coefficient a and a constant b in the later-described expression (3) are expressed as a quadratic function of the separation distance D from the coil to the measured object, as shown in the later-described expressions (4) and (5). (That is, the deviation ΔS has a correlation shown in the later-described equations (4) and (5) with respect to the separation distance D).

Furthermore, the temperature t of the measured object can be expressed by the following equation (6).
Therefore, the arithmetic processing means in the measurement apparatus performs arithmetic processing for substituting a and b calculated by the above formulas (4) and (5) into formula (6) described later, thereby Determine the temperature t. The separation distance D used in the process of calculating the temperature t in the later-described equation (6) is a highly accurate first signal S1 and second signal S2 detected by a coil located in the temperature-dependent region and having high distance dependency. Therefore, the temperature t of the measurement object can be measured with high accuracy.

According to a third aspect of the present invention, in the measurement apparatus according to any one of the first or second aspects, the display device displays a calculation result of the calculation processing unit, and a recording unit records the calculation result. It is characterized by that.
Thereby, the separation distance D from the coil to the measured object or the temperature t of the measured object can be easily visually recognized by the display means. Further, since the distance D to the measurement object or the temperature t of the measurement object, which is the calculation result, can be left in the recording means, the measurement result can be easily evaluated later.

According to a fourth aspect of the present invention, there is provided a first coil that is disposed opposite to a conductive or semiconductive object to be measured at a distance and is excited by an alternating current, the first coil is excited by an alternating current, and the first coil is excited. A first conversion circuit that outputs a first signal that is involved in a change in impedance of one coil and that depends on the temperature of the object to be measured; and the same separation as the first coil with respect to the object to be measured A second coil that is arranged oppositely and is excited by an alternating current, and a change that excites the second coil by an alternating current and that is involved in a change in impedance of the second coil and that depends on the temperature of the object to be measured. A second conversion circuit that outputs a second signal that is a quantity; and an arithmetic processing means that receives the first signal and the second signal and performs predetermined arithmetic processing on these signals; and From the measurement object A measurement method for measuring a separation distance, wherein the first coil, the first conversion circuit, the second coil, and the second conversion circuit have characteristics of the first signal and the second signal, respectively. The first coil, the first conversion circuit, and the second coil, which are obtained by measuring, and having a combination in which the polarities in the characteristics of the first signal and the second signal are opposite and the absolute values are approximately the same In this case, the selected one of the second conversion circuits is used, and an average value of distances obtained from the first signal and the second signal by the arithmetic processing unit is used to determine the distance between the measured object and each coil. The separation distance is calculated.
In the measurement method, similarly to the measurement apparatus according to the first aspect, the distance from the first and second coils to the measured object can be measured with high accuracy without contact.

  According to the first aspect of the present invention, from the first signal involved in the impedance change of the first coil approaching the measured object and the second signal involved in the impedance change of the second coil approached to the measured object, The distance from each coil to the measured object is calculated. At that time, both the first coil that outputs the first signal and the second coil that outputs the second signal have temperature dependence that increases the temperature dependence of the first signal and the second signal with respect to the measured object. Since it is located in the region, the distance dependency in the first signal and the second signal also increases. That is, in the measurement apparatus, the distance is calculated based on the first signal and the second signal having a large distance dependency, so that the distance from each coil to the measured object can be measured with high accuracy without contact. become.

According to the invention of claim 2, the deviation ΔS between the first signal S1 and the second signal S2 is a linear function of the temperature t of the measured object, as shown on the right side of the later-described equation (3), and is linear. Showing gender. A coefficient a and a constant b in the later-described expression (3) are expressed as a quadratic function of the separation distance D from the coil to the measured object, as shown in the later-described expressions (4) and (5). be able to. Furthermore, the temperature t of the measured object can be expressed by the following equation (6).
Therefore, the arithmetic processing means in the invention of claim 2 performs the arithmetic processing by substituting a and b calculated in the later-described equations (4) and (5) into the later-described equation (6), thereby measuring Find body temperature t. The separation distance D used in the process of calculating the temperature t in the later-described equation (6) is a highly accurate first signal S1 and second signal S2 detected by a coil located in the temperature-dependent region and having high distance dependency. Therefore, the temperature t of the measurement object can be measured with high accuracy.

  According to the third aspect of the present invention, the distance from the coil to the object to be measured or the temperature t of the object to be measured, which is the calculation result, can be easily visually recognized by the display means. Further, since the distance D to the measurement object or the temperature t of the measurement object, which is the calculation result, can be left in the recording means, the measurement result can be easily evaluated later.

  According to the fourth aspect of the present invention, the distance from the first and second coils to the object to be measured can be measured with high accuracy in a non-contact manner, similarly to the measurement apparatus of the first aspect.

It is a mimetic diagram showing a schematic structure of a measuring device in one embodiment concerning the present invention. FIG. 2 is a block diagram illustrating a specific circuit configuration of a first conversion circuit in FIG. 1. FIG. 3 is a block diagram illustrating a specific circuit configuration of a second conversion circuit in FIG. 1. It is a graph which shows the correlation with the 1st signal and 2nd signal which the measuring apparatus of one Embodiment of this invention detects, the separation distance D between a coil and a to-be-measured body, and the temperature t of a to-be-measured body. In the measuring apparatus of one embodiment of the present invention, it is a graph which shows correlation between slope a and intercept b of deviation delta S of 1st signal S1 and 2nd signal S2, and separation distance D to a to-be-measured object. 5 is a flowchart illustrating a procedure for measuring a separation distance D to a measurement object and a temperature of the measurement object in the measurement apparatus according to the embodiment of the present invention. It is the graph which showed the tendency for the temperature dependence and distance dependence of an exciting coil to change with the separation distance to a to-be-measured body.

Hereinafter, one embodiment of a measuring device concerning the present invention is described in detail with reference to drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of a measuring apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing a specific circuit configuration of the first conversion circuit of FIG. FIG. 3 is a block diagram showing a specific circuit configuration of the second conversion circuit of FIG.

  The measuring apparatus 1 according to this embodiment includes a first circuit 20 and a second circuit 30 that are arranged to face a conductive or semiconductive object to be measured 10 at a distance, and the first circuit 20 and the second circuit 30. An arithmetic processing unit 40 that performs arithmetic processing on the output signal of the circuit 30 and a display / recording unit 50 that displays and records the arithmetic processing process and the arithmetic result in the arithmetic processing unit 40 are provided.

  As shown in FIG. 1, the first circuit 20 includes a first coil (first inductive element) 21 that is opposed to the measured object 10 with a separation distance D and is excited by an alternating current, and the first coil. And a first conversion circuit 22 that excites 21 with an alternating current.

While the first conversion circuit 22 excites the first coil 21, the first conversion circuit 22 is involved in a change in impedance of the first coil 21 due to the influence of eddy current generated in the measured object 10 and changes depending on the temperature of the measured object 10. The first signal S1, which is a quantity, is output.
As shown in FIG. 2, the first conversion circuit 22 of the present embodiment is obtained from an oscillation circuit 61 that excites the first coil 21 with an alternating current to form a resonance circuit including the first coil 21, and the oscillation circuit 61. A detection circuit 62 that detects and outputs the resonance voltage (unit: V), and an amplification circuit 63 that amplifies and outputs the resonance voltage output from the detection circuit 62. The signal output from the amplifier circuit 63 is the first signal S1.

  As shown in FIG. 1, the second circuit 30 is disposed opposite to the device under test 10 with the same separation distance D as the first coil 21 and is excited by an alternating current (second induction). Element) 31 and a second conversion circuit 32 for exciting the second coil 31 with an alternating current.

While the second conversion circuit 32 excites the second coil 31, the second conversion circuit 32 is involved in the change in impedance of the second coil 31 due to the influence of the eddy current generated in the measured object 10 and changes depending on the temperature of the measured object 10. The second signal S2, which is a quantity, is output.
The second conversion circuit 32 of the present embodiment has a functional configuration similar to that of the first conversion circuit 22 and, as shown in FIG. 3, a resonance circuit including the second coil 31 by exciting the second coil 31 with an alternating current. An oscillation circuit 65 to be formed; a detection circuit 66 that detects and outputs a resonance voltage (unit: V) obtained from the oscillation circuit 65; an amplification circuit 67 that amplifies and outputs the resonance voltage output from the detection circuit 66; It has. The signal output from the amplifier circuit 67 is the second signal S2.

  The first coil 21 and the second coil 31 have a temperature dependent region (with respect to the measured object 10) so that the temperature dependency in the first signal and the second signal output from the amplifier circuits 63 and 67 is increased. It is arranged in the temperature dependent region A1) shown in FIG.

  In addition, the first coil 21, the first conversion circuit 22, the second coil 31, and the second conversion circuit 32 are obtained by measuring the characteristics of the first signal S1 and the second signal S2, respectively. The first coil 21, the first conversion circuit 22, the second coil 31, and the second conversion circuit 32 have a combination in which the polarities in the characteristics of the S1 and the second signal S2 are opposite and have the same absolute value. Is selected.

  The polarity and magnitude of the first signal S1 and the second signal S2 are the magnitude of the coils 21 and 31, the number of turns of the coils 21 and 31, the material of the iron core of the coils 21 and 31, the oscillation frequency, and the signal in the conversion circuits 22 and 32. It varies depending on the processing method, etc., and varies depending on the manufacturer and model. For this reason, the first coil 21, the first conversion circuit 22, the second coil 31, and the second conversion circuit 32 understand the temperature dependence on the temperature of the device under test 10 and then determine the temperature of the device under test 10. The first circuit 20 and the second circuit 20 have the same absolute value of the resonance voltage output in response to the temperature change, and the polarity of the resonance voltage output in response to the temperature change of the measured object is reversed. A circuit 30 is constructed.

In the present embodiment, the first circuit 20 is, for example, a product of NSD Corporation, and includes a first coil 21 of model GPS-2818M and a first conversion circuit 22 of model GTN-121VN.
The second circuit 30 combined with the first circuit 20 is, for example, a product of Keyence Corporation, and includes the second coil 31 of the model AH-440 and the second conversion circuit 32 of the model AS-440. .
In the combination of the first circuit 20 and the second circuit 30, the polarities of the first signal S1 and the second signal S2 are reversed, and the absolute values of the first signal S1 and the second signal S2 are approximately the same. (Approximate).

The resonance voltage output from the detection circuit 62 of the first conversion circuit 22 and the resonance voltage output from the detection circuit 66 of the second conversion circuit 32 both change in accordance with the change in impedance of the coils 21 and 31. And the amount of change depending on the temperature of the DUT 10.
The amplification circuit 63 of the first conversion circuit 22 and the 67 of the second conversion circuit 32 set the resonance voltage value output from the detection circuits 62 and 66 to 1 V corresponding to the separation distance D from the measured object 10 to each coil. The first signal S1 and the second signal S2 are amplified at a ratio of / mm. The first signal and the second signal output from the amplifier circuit are amplified to a distance from the measured object to the coil by amplifying the voltage value at a rate of 1 V / mm corresponding to the distance from the measured object to the coil. Correlated data. Then, the average value of the first signal and the second signal can correspond to the separation distance D (unit: mm) from each coil to the object to be measured, and the arithmetic processing means is a correlation equation indicating distance dependency. The distance D from the coil to the object to be measured can be obtained by a simple calculation process of calculating the average value of the first signal and the second signal without analyzing the above, thereby speeding up the calculation of the distance can do.

Next, a measurement method for measuring the separation distance from the measurement object using the measurement apparatus having the above configuration will be described.
FIG. 4 shows an apparatus configuration of one embodiment shown in FIG. 1 in which the distance D from each of the coils 21 and 31 to the DUT 10 is 4 of 0.95 mm, 1.95 mm, 2.95 mm, and 4.95 mm. In other words, the measurement results of the first signal S1 and the second signal S2 are summarized in a graph for each separation distance D.

  In the graph on the left side in FIG. 4, the first signal S1 detected by changing the temperature t of the measured object 10 from 20 ° C. to 80 ° C. for each separation distance D from each of the temperature conditions, and the second signal. The signal S2, the average value of the first signal S1 and the second signal S2, and the respective separation distances D are plotted. In each graph on the left side in FIG. 4, the vertical axis represents the voltage value (unit: V), and the horizontal axis represents the temperature t of the measured object 10.

The average voltage value of the first signal and the second signal shown in each graph on the left side in FIG. 4 matches the value of the separation distance D from the measured object 10 to each coil. This is because the amplification circuits 63 and 67 amplify the resonance voltage at a rate of 1 V / mm corresponding to the separation distance D from the DUT 10 to the coil. Therefore, when the arithmetic processing means 40 of this embodiment receives the first signal S1 and the second signal S2 from the first circuit 20 and the second circuit 30, the arithmetic processing means 40 performs arithmetic processing shown in the following equation (1). Then, the processing result is defined as a separation distance D from the coils 21 and 31 to the measured object 10.
D = (S1 + S2) / 2 (1)

The graph on the right side in FIG. 4 shows the first signal S1 and the second signal detected under the respective temperature conditions by changing the temperature t of the measured object 10 from 20 ° C. to 80 ° C. for each separation distance D. The deviation ΔS from S2 is calculated and plotted for each separation distance D. In each graph on the right side in FIG. 4, the vertical axis represents the deviation ΔS (unit: V), and the horizontal axis represents the temperature t of the measured object 10. The deviation ΔS is a difference between the first signal S1 and the second signal S2, and is expressed by the following equation (2).
ΔS = S1-S2 (2)

As apparent from the graph on the right side in FIG. 4, the deviation ΔS between the first signal S1 and the second signal S2 is a linear function of the temperature t of the device under test 10 and exhibits linearity. Accordingly, the deviation ΔS and the temperature t of the measured object have a correlation shown in the following equation (3).
ΔS = S1-S2 = a × t + b (3)

  In the above equation (3), the coefficient a is the slope of the characteristic line ΔS (the unit is V / ° C.). In the above equation (3), the constant b is an intercept (unit: V) that is an intersection with the vertical axis when t = 0 in the above equation (3).

  The correlation between the slope a and the separation distance D of the intercept b in the above equation (3) is as shown in Table 1 below.

When the slope a and the intercept b shown in Table 1 are plotted on a graph, the characteristics of the parabola are shown as shown in FIG. Therefore, the inclination a and the intercept b are expressed as a quadratic function of the separation distance D from the coils 21 and 31 to the measured object 10 as shown in the following equations (4) and (5). (That is, the slope a and the intercept b have the correlation shown in the following equations (4) and (5) with respect to the separation distance D).
a = -7.883 × 10 ⁻⁵ D ² + 9.226 × 10 ⁻⁴ D + 1.494 × 10 ⁻³ (4)
b = -0.962 × 10 ⁻² D ² + 1.702 × 10 ⁻² D + 7.016 × 10 ⁻² (5)

Further, the temperature t of the measured object 10 can be expressed by the following equation (6) by modifying the above equation (3).
t = (ΔS−b) / a (6)

  The arithmetic processing means in the measuring apparatus performs the arithmetic processing by substituting a and b calculated by the above formulas (4) and (5) into the above formula (6), thereby obtaining the temperature of the measured object 10. t is obtained. At this time, D used in the process of calculating the temperature t by the above equation (6) is a highly accurate first signal S1 detected by the coils 21 and 31 that are located in the temperature-dependent region and have high distance dependency. Since it is calculated from the second signal S2, the temperature t of the measured object can be calculated with high accuracy.

  As shown in FIG. 1, the display / recording unit 50 displays the calculation processing process and calculation results in the calculation processing means 40 and the display means 51 that displays the calculation processing processes and calculation results in the calculation processing means 40. Recording means 52.

The measuring apparatus 1 described above measures the separation distance D from the first coil 21 and the second coil 31 to the measured object 10 and the temperature t of the measured object 10 according to the procedure shown in FIG.
When the measurement process is started, first, in step S101, from the average value of the first signal S1 that is the output signal of the first circuit 20 and the second signal S2 that is the output signal of the second circuit 30 to the device under test 10. Is determined.
Next, in the next step S102, the separation distance D calculated in step S101 is substituted into the above equations (4) and (5) to obtain the inclination a and the intercept b.
Next, in the next step S103, the deviation ΔS is obtained from the above equation (3).
Next, in the next step S104, the temperature of the DUT 10 is calculated based on the above equation (6).
The arithmetic processing shown in steps S101 to S104 above is performed by the arithmetic processing means 40.
Next, when the calculated temperature t of the measured object 10 is displayed on the display means 51 and recorded in the recording means 52 in the next step S105, a series of processing ends.

  In the embodiment of the present invention described above, the first signal S1 related to the impedance change of the first coil 21 close to the measured object 10 and the impedance change of the second coil 31 close to the measured object 10 are used. A distance D from each of the coils 21 and 31 to the measured object 10 is calculated from the second signal S2 involved. At that time, the first coil 21 that outputs the first signal S1 and the second coil 31 that outputs the second signal S2 both have the temperature in the first signal S1 and the second signal S2 with respect to the measured object 10. Since it is located in the temperature dependent region where the dependency becomes large, the distance dependency in the first signal S1 and the second signal S2 also increases. That is, in the measurement apparatus 1 according to the embodiment, since the distance is calculated based on the first signal S1 and the second signal S2 having a large distance dependency, the separation distance D from each coil to the measured object 10 is determined in a non-contact manner. It becomes possible to measure with high accuracy.

  In the present embodiment, the first signal S1 and the second signal S2 output from the amplifier circuits 63 and 67 amplify the resonance voltage value at a rate of 1 V / mm according to the distance from the measured object 10 to the coil. By performing the processing, the data correlates with the separation distance D from the measured object 10 to the coils 21 and 31. And the average value of 1st signal S1 and 2nd signal S2 corresponds to the separation distance D (unit mm) from each coil 21 and 31 to the to-be-measured body 10. FIG. Therefore, the arithmetic processing means 40 does not analyze the correlation equation indicating the distance dependence, and calculates a simple calculation that calculates the average value of the first signal S1 and the second signal S2 expressed by the above-described equation (1). In the processing, the separation distance D from the coils 21 and 31 to the measured object 10 can be obtained, and the calculation of the distance can be speeded up.

Further, in the present embodiment, the deviation ΔS between the first signal S1 and the second signal S2 is a linear function of the temperature t of the measured object 10, as shown on the right side of the above-described equation (3). Indicates. That is, the deviation ΔS and the temperature t of the measured object 10 have a correlation shown in the above-described equation (3).
In the above equation (3), the coefficient a is the slope of the characteristic line ΔS (unit is V / ° C.), and the constant b is the vertical axis when t = 0 in the above equation (3). Is the intercept (unit is V).
Then, the coefficient a and the constant b can be expressed as a quadratic function of the separation distance D from the coil to the measured object 10 as shown in the above equations (4) and (5) (ie, The deviation ΔS has the correlation shown in the above-described equations (4) and (5) with respect to the separation distance D).
Further, the temperature t of the DUT 10 can be expressed by the above formula (6) by modifying the above formula (2).
Therefore, the arithmetic processing means 40 in the measurement apparatus 1 performs arithmetic processing by substituting a and b calculated in the above formulas (4) and (5) into the above formula (6), thereby measuring The temperature t of the body 10 is obtained. D used in the process of calculating the temperature t in the above-described equation (6) is a highly accurate first signal S1 and second signal detected by the coils 21 and 31 that are located in the temperature-dependent region and have high distance dependency. Since it is calculated from S2, the temperature t of the measured object 10 can be measured with high accuracy.

  In this embodiment, the distance D from the coils 21 and 31 to the measured object 10 or the temperature t of the measured object 10 as the calculation result can be easily visually recognized by the display means 51. Moreover, since the separation distance D to the measured object 10 or the temperature t of the measured object 10 which is the calculation result can be left in the recording means 52, the measurement result can be easily evaluated later.

  Moreover, in this embodiment, the 1st circuit 20 which is a product of NS Inc. which is a component of the measuring apparatus 1 and the second circuit 30 which is a product of Keyence Corporation are the outputs of the respective circuits. This is a circuit in which the first signal S1 and the second signal S2, which are signals, have opposite polarities and have the same absolute value. Therefore, by combining the first circuit 20 and the second circuit 30, a device configuration in which the polarities of the first signal S1 and the second signal S2 are opposite and the absolute values are almost the same can be easily constructed. Therefore, the distance D between the conductive or semiconductive measured object 10 and the temperature t of the measured object 10 can be measured with high accuracy without contact.

DESCRIPTION OF SYMBOLS 10 to-be-measured object 21 1st coil 22 1st conversion circuit 31 2nd coil 32 2nd conversion circuit 40 Arithmetic processing means 50 Display / recording part 51 Display means 52 Recording means D Separation distance S1 1st signal S2 2nd signal t Temperature

Claims (4)

A first coil that is disposed opposite to a conductive or semiconductive object to be measured at a distance and is excited by an alternating current;
A first conversion circuit that excites the first coil with an alternating current and outputs a first signal that is involved in a change in the impedance of the first coil and that is a change amount that depends on the temperature of the measured object;
A second coil that is arranged opposite to the object to be measured at the same separation distance as the first coil and is excited by an alternating current;
A second conversion circuit that excites the second coil with an alternating current and outputs a second signal that is involved in a change in impedance of the second coil and that depends on the temperature of the object to be measured;
Arithmetic processing means for receiving the first signal and the second signal and performing predetermined arithmetic processing on these signals;
With
The first coil, the first conversion circuit, the second coil, and the second conversion circuit are obtained by measuring characteristics of the first signal and the second signal, and the first signal, A selection of the first coil, the first conversion circuit, the second coil, and the second conversion circuit in which the polarities in the characteristics of the second signal are reversed and the absolute values are about the same. use,
The measurement apparatus is characterized in that the arithmetic processing means calculates a separation distance between the measured object and each coil from the first signal and the second signal.   The arithmetic processing means calculates a deviation ΔS = S1-S2 which is a difference between the first signal S1 and the second signal S2, and further, a correlation between the deviation ΔS and the temperature t of the measured object, and The measuring apparatus according to claim 1, wherein the temperature t of the object to be measured is calculated from the correlation between the deviation ΔS and the previously calculated separation distance.   The measuring apparatus according to claim 1, further comprising: a display unit that displays a calculation result of the calculation processing unit; and a recording unit that records the calculation result. A first coil that is disposed opposite to a conductive or semiconductive object to be measured at a distance and is excited by an alternating current;
A first conversion circuit that excites the first coil with an alternating current and outputs a first signal that is involved in a change in the impedance of the first coil and that is a change amount that depends on the temperature of the measured object;
A second coil that is arranged opposite to the object to be measured at the same separation distance as the first coil and is excited by an alternating current;
A second conversion circuit that excites the second coil with an alternating current and outputs a second signal that is involved in a change in impedance of the second coil and that depends on the temperature of the object to be measured;
Arithmetic processing means for receiving the first signal and the second signal and performing predetermined arithmetic processing on these signals;
A measuring method for measuring a separation distance from the measured object,
The first coil, the first conversion circuit, the second coil, and the second conversion circuit are obtained by measuring characteristics of the first signal and the second signal, and the first signal, A selection of the first coil, the first conversion circuit, the second coil, and the second conversion circuit in which the polarities in the characteristics of the second signal are reversed and the absolute values are about the same. use,
A measurement method characterized in that the arithmetic processing means calculates a separation distance between the measured object and each coil from an average value of distances obtained from the first signal and the second signal, respectively.

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