JP5574482B2 - Magnetic sensor and detection device for EMC test - Google Patents

Description

  The present invention relates to a magnetic sensor and an EMC test detection device, and more particularly to a magnetic sensor and an EMC test detection device suitable for detecting a high frequency magnetic field in the GHz band.

  Patent Document 1 discloses a magnetic sensor that exhibits a smooth response up to an ultra-high frequency with respect to a high-frequency magnetic field strength. This type of magnetic sensor includes a shielded loop coil that functions as a sensor that detects magnetism, a high-frequency connection connected to a coaxial line, and the like, and an output lead that connects the shielded loop coil and the high-frequency connection. It is configured. The size of the shielded loop coil 100 is a rectangle of 3.6 [mm] × 6.8 [mm] on the outside and a rectangle of 1.8 [mm] × 4.8 [mm] on the inside. It is said that.

JP 2004-069337 A

  In the magnetic sensor disclosed in Patent Document 1, the shielded loop coil has a relatively large area. In this case, the via formation position does not become a problem in consideration of the size of the via.

  However, in recent years, the area of a shielded loop coil has been reduced due to the demand for high resolution with the miniaturization of components. For this reason, there is a problem that it is difficult or impossible to form the via on the shielded loop coil. If the via formation position is not preferable, for example, there is an influence such as deterioration of frequency characteristics due to a decrease in self-resonance frequency, or deterioration of electric field shielding.

  Accordingly, an object of the present invention is to provide a small magnetic sensor in which the via formation position is devised under the condition that the frequency characteristics are not deteriorated due to the decrease of the self-resonance frequency or the electric field shielding property is not deteriorated. .

In order to solve the above problems, the present invention provides a magnetic sensor and an EMC test detection apparatus according to the present invention.
A signal line in which a linear first portion, a loop-shaped second portion adjacent to the first portion, and a circular third portion adjacent to the second portion are arranged in series;
The third portion is an end portion of the signal line, and is arranged in parallel with the first portion.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same part.

(Embodiment 1)
FIG. 1 is a schematic exploded view of a shielded loop coil constituting the magnetic sensor of Embodiment 1 of the present invention. 1A shows the first substrate 10 on which the ground line 12 is formed, FIG. 1B shows the second substrate 20 on which the signal line 22 is formed, and FIG. 1C shows the ground. The 3rd board | substrate 30 with which the track | line 32 was formed is shown. The first substrate 10, the second substrate 20, and the third substrate 30 are so-called insulating substrates, and a so-called triplate structure magnetic sensor is formed by combining them in multiple layers.

  First, the configuration of the second substrate 20 will be described. As shown in FIG. 1B, the signal line 22 includes a first portion 24 that is also referred to as a linear impedance line, and a loop-shaped second portion that is also referred to as a loop portion adjacent to the first portion 24. 26 and a circular third portion 28, also referred to as a week end portion, adjacent to the second portion 26 are arranged in series. The third portion 28 is an end portion of the signal line 22 and is disposed in parallel with the first portion 24. As a known material for the signal line 22, for example, copper can be used.

  Here, when an example of the size of the signal line 22 is shown, first, the width of the signal line 22 is set to about 0.02 mm. The size of the second portion 26 is mainly determined by the width of the tip of the second substrate 20.

  That is, in the example shown in FIG. 1, for example, 2 mm is secured as the width of the tip of the second substrate 20, and in this case, the second portion 26 has a length in the longitudinal direction of 1.86 mm, for example, and is short. The length in the hand direction can be 0.24 mm.

  On the other hand, when 1 mm can be secured as the width of the tip of the second substrate 20, for example, the second portion 26 has a length in the longitudinal direction of 0.86 mm and a length in the short direction of 0.23 mm. be able to.

  Furthermore, when 0.5 mm can be secured as the width of the tip of the second substrate 20, for example, the second portion 26 has a length in the longitudinal direction of 0.44 mm and a length in the short direction of 0.18 mm. It can be.

  In addition, the third portion 28 can be formed in a donut shape having a through hole diameter of, for example, 0.2φ and a pad outer diameter of 0.4φ, for example. The through hole is constituted by a via and a pad.

  Next, the configuration of the first substrate 10 and the third substrate 30 will be described. As shown in FIGS. 1A and 1C, the ground lines 12 and 32 correspond to the first regions 14 and 34 having a shape corresponding to the first portion 24 and the second portion 26 and correspond to the second regions 26. The second regions 16 and 36 having a width exceeding the width of the first regions 14 and 34, and the first regions 14 and 34 and the second regions 16 and 36 are formed so as to correspond to the third portion 28. And three regions 18, 38.

  Here, the sizes of the ground lines 12 and 32 depend on the sizes of the first substrate 10 and the third substrate 30. As an example of the size of the ground lines 12 and 32, the width of the first regions 14 and 34 is about 0.2 mm to 0.3 mm.

  If, for example, 2 mm can be secured as the width of the tip of the first substrate 10 and the third substrate 30, for example, a width of 0.16 mm and a magnetic flux change detection region having a size of about 0.08 mm × 1.68 mm are obtained. The second regions 16 and 36 can be formed under conditions.

  On the other hand, when 1 mm can be secured as the width of the tip of the first substrate 10 and the third substrate 30, for example, a width of 0.15 mm and a magnetic flux change detection area of about 0.08 mm × 0.70 mm are obtained. The second regions 16 and 36 can be formed under conditions.

  Furthermore, when 0.5 mm can be secured as the width of the tip of the first substrate 10 and the third substrate 30, for example, a magnetic flux change detection region having a width of 0.10 mm and a size of about 0.08 mm × 0.38 mm. The second regions 16 and 36 can be formed under the following conditions.

  Further, the third regions 18 and 38 can be vias of about 0.2φ.

  Here, as is clear from FIGS. 1A to 1C, in the case of the shielded loop coil according to the present embodiment, the size of the third portion 28 is the width of the ground line in the second regions 16 and 36. Bigger than.

  Then, unlike the magnetic sensor disclosed in Patent Document 1, the third portion 28 cannot be provided at a position corresponding to the second regions 16 and 36. Therefore, in the present embodiment, the third portion 28 is provided not at a position corresponding to the second areas 16 and 36 but at a position adjacent to the first areas 14 and 34 in parallel.

(Embodiment 2)
FIG. 2 is a schematic exploded view of a shielded loop coil constituting the magnetic sensor according to the second embodiment of the present invention. 2A to 2C correspond to FIGS. 1A to 1C, respectively.

The shielded loop coil shown in FIG. 2 differs from the shielded loop coil shown in FIG. 1 in the following points. That is,
1. The position of the third portion 28 is set so that the central portion thereof is, for example, about 0.7 mm to 0.85 mm from the tip of the second substrate 20, and
2. Further, the position of the third portion 28 is set so that the center portion is the center of the second substrate 20 in the short direction,
3. Accordingly, the formation positions of the third regions 18 and 38 are also changed, and
4). The first portion 24 has a convex portion 24A corresponding to the position of the third portion 28.
Is different.

  The distance of the third portion 28 with respect to the tip of the second substrate 20 is preferably as short as possible from the viewpoint of the resonance frequency with respect to the magnetic flux. Therefore, if only this point is taken into consideration, the one shown in FIG. 1 is preferable to the shielded loop coil shown in FIG.

  However, the shielded loop coil of the present embodiment can realize the symmetry of the shape of the signal line 22 by the change according to 2 above. This has the merit that the electric field shielding characteristic is improved on the magnetic field detection surface as compared with the shielded loop coil shown in FIG.

(Embodiment 3)
FIG. 3 is a schematic exploded view of a shielded loop coil constituting the magnetic sensor of Embodiment 3 of the present invention. FIGS. 3A to 3C correspond to FIGS. 2A to 2C, respectively.

The shielded loop coil shown in FIG. 3 is different from the shielded loop coil shown in FIG. 2 in the following points. That is,
1. The position of the third portion 28 is decentered from the center in the short direction of the second substrate 20 by the center portion.
2. Accordingly, the size of the third regions 18 and 38 is reduced.
Is different.

  If the size of the third regions 18 and 38 can be reduced, the influence of the electric field can be reduced, and the electric field shielding property is improved. Further, in the case of the shielded loop coil shown in FIG. 3, it is possible to maintain the symmetry of the shape as in the shielded loop coil shown in FIG.

(Embodiment 4)
FIG. 4 is a schematic configuration diagram of a shielded loop coil according to the fourth embodiment of the present invention. In the case of the shielded loop coil according to the first to third embodiments, the signal line 24 is formed with the same width in all of the first portion to the third portion.

  On the other hand, in the shielded loop coil of the present embodiment, the signal line width in the second portion 26 is increased from the middle. Specifically, the signal line width is increased from 0.02 mm to 0.16 mm from near the center of the second portion 26.

  Here, although the signal line width is increased from the vicinity of the center of the second portion 26, the present invention is not limited to this. That is, the signal line width may be wider on the first portion 24 side than near the center of the second portion 26, or conversely, the signal line width may be wider on the third portion 28 side than near the center of the second portion 26. Is possible.

  In the former case, since the self-resonant frequency increases, the frequency characteristics may be improved. On the other hand, the position ambiguity increases due to the increase in the line width, and the resolution may decrease. As will be described later, the resolution means that when an EMC noise source is located immediately below the magnetic sensor, the output of the magnetic sensor becomes a maximum value. From this maximum value, for example, to a position where the electric field strength decreases by 6 dB. This is the distance traveled when moving in the horizontal direction. The reason for the degradation is that the second regions 16 and 36 of the ground lines 12 and 32 can be regarded as passing transmission lines on the first regions 14 and 34 side from the center, and the third regions 18 and 38 from the center. This is because the transmission line can be regarded as a transmission line having a short-circuited end.

  Therefore, on the contrary, in the latter case, on the contrary, there is a trade-off relationship that the frequency characteristic may be lowered, while the resolution may be improved.

  Therefore, in a field where excellent frequency characteristics are required, a magnetic sensor including a shielded loop coil having a signal line width wider on the first portion 24 side than near the center of the second portion 26 is suitable. .

  On the other hand, in a field where excellent resolution is required, a magnetic sensor including a shielded loop coil having a signal line width wider on the third portion 28 side than near the center of the second portion 26 is suitable.

  The example shown in FIG. 4 is for improving the frequency characteristic and the resolution in a balanced manner with respect to that shown in FIG. 1. In view of the above circumstances, the signal line width is increased from the vicinity of the center of the second portion 26. It is spreading.

  FIG. 5 is a diagram illustrating frequency characteristics of the magnetic sensor according to the shielded loop coil illustrated in FIGS. 3 and 4. In FIG. 5, the horizontal axis indicates frequency [GHz], and the vertical axis indicates sensitivity. As shown in FIG. 5, it can be seen that the frequency characteristic of the magnetic sensor according to the shielded loop coil shown in FIG. 4 is superior to the magnetic sensor according to the shielded loop coil shown in FIG.

  FIG. 6 is a diagram showing a measurement result of the so-called vertical coil type spatial resolution related to the shielded loop coil shown in FIG. The horizontal axis in FIG. 6 indicates the horizontal distance [mm] between the magnetic sensor and the measurement target, and the vertical axis indicates the electric field strength [dB].

  Here, the spatial resolution is measured by changing the vertical distance [mm] between the magnetic sensor and the measurement object, as shown in the frame in FIG. doing. FIG. 6 shows how the output from the magnetic sensor changes depending on the vertical distance between the signal line and the magnetic coil.

  As shown in FIG. 6, it can be seen that the closer the horizontal distance between the magnetic sensor and the measurement object is to 0 mm, the better the electric field strength. It can also be seen that the closer the vertical distance between the magnetic sensor and the measurement object is to 0 mm, the better the electric field strength. Furthermore, it can be seen that the electric field strength is substantially the same when the horizontal distance between the magnetic sensor and the measurement object increases in the plus direction and when it increases in the minus direction.

  FIG. 7 is a diagram showing the measurement result of the so-called horizontal coil type spatial resolution related to the shielded loop coil shown in FIG. In FIG. 7, the horizontal axis indicates the horizontal distance [mm] between the magnetic sensor and the measurement target, and the vertical axis indicates the electric field strength [dB].

  Here, as in the case of FIG. 6, the spatial resolution is measured by changing the vertical distance [mm] between the magnetic sensor and the measurement target. As shown in FIG. 7, it can be seen that the electric field strength deteriorates when the horizontal distance between the magnetic sensor and the measurement object is around 0 mm. It can also be seen that the closer the horizontal distance between the magnetic sensor and the measurement object is to 0 mm, the better the electric field strength. Furthermore, it can be seen that the electric field strength is substantially the same when the horizontal distance between the magnetic sensor and the measurement object increases in the plus direction and when it increases in the minus direction.

(Embodiment 5)
FIG. 8 is a schematic external view of the EMC test detection apparatus according to the embodiment of the present invention. The EMC test detection apparatus shown in FIG. 8 includes a table 100 on which an inspection object is placed, an emergency stop button 110A and an operation button 110B provided on the table 100, and a magnetic sensor according to the first embodiment. A probe 150 attached to the probe 150, a probe chuck 130 for gripping the probe 150, a laser 120 for defining the position of the probe 150 and the inspection object, light emission and reception processing of the laser 120, and rotation processing of the probe chuck 130 And a processing unit 140 that performs signal amplification processing from the magnetic sensor, an X-direction moving unit 160 that moves the processing unit 140 in the XYZ directions, a Y-direction moving unit 170, a Z-direction moving unit 180, and a table 100, respectively. An imaging unit 190 that images an inspection object to be placed, and an arm unit 200 that moves the imaging unit 190 in a plane direction , And a controller unit 210 for controlling the operation of each section.

  This EMC test detection apparatus is connected to a personal computer or the like. In response to a signal from an input device such as a mouse, the controller unit 210 outputs an operation command to each unit, and as a result, image data from the imaging unit 190 is displayed on an output device such as a display.

  Next, the method of use and operation of the EMC test detection apparatus shown in FIG. 8 will be described. First, an inspection object is placed on the placement table 100 of the EMC test detection apparatus. Next, when the operation button 110B is pressed while the EMC test detection device is turned on, the controller unit 210 responds accordingly to the probe chuck 130, the X direction moving unit 160, the Y direction moving unit 170, Z. A driving signal is appropriately output to the direction moving unit 180. As a result, the processing unit 140 starts to rotate or move.

  At this time, the laser 120 is emitted from the processing unit 140, and the laser 120 is received by the processing unit 140. Thus, by measuring the distance between the probe 150 and the inspection object, a predetermined height is traced from the inspection object to avoid collision between the probe 150 and the inspection object, and the magnetic sensor attached to the probe 150. To prevent damage. Note that the movement of the processing unit 140 can also be stopped by the user pressing the emergency stop button 110A.

  Next, magnetic noise sensing is performed by a magnetic sensor attached to the probe 150. The sensing result is subjected to signal amplification processing or the like in the processing unit 140 and output to the personal computer via the controller unit 210.

  Separately, the controller unit 210 moves the arm unit 200 in accordance with a signal from an input device such as a mouse connected to the personal computer, and causes the imaging unit 190 to image the inspection target, and the imaging result. Is output to the personal computer.

  As a result, it is possible to display the imaging result and the sensing result through a display or the like connected to the personal computer.

  The present invention can be used at the time of inspection for a source of EMC noise.

It is a typical exploded view of the shielded loop coil which constitutes the magnetic sensor of Embodiment 1 of the present invention. It is a typical exploded view of the shielded loop coil which comprises the magnetic sensor of Embodiment 2 of this invention. It is a typical exploded view of the shielded loop coil which comprises the magnetic sensor of Embodiment 3 of this invention. It is a typical block diagram of the shielded loop coil which concerns on Embodiment 4 of this invention. It is a figure which shows the frequency characteristic of the magnetic sensor which concerns on the shielded loop coil shown in FIG.3 and FIG.4. It is a figure which shows the measurement result of the spatial resolution of what is called a vertical coil type which concerns on the shielded loop coil shown in FIG. It is a figure which shows the measurement result of the spatial resolution of what is called a horizontal coil type which concerns on the shielded loop coil shown in FIG. It is a typical external view of the detection apparatus for EMC tests of an embodiment of the present invention.

DESCRIPTION OF SYMBOLS 10 1st board | substrates 12 and 32 Ground line 20 2nd board | substrate 22 Signal line 30 3rd board | substrate 100 Disposition stand 110A Emergency stop button 110B Operation button 120 Laser 130 Probe chuck 140 Processing part 150 Probe 160 X direction moving part 170 Y direction moving part 180 Z-direction moving unit 190 Imaging unit 200 Arm unit 210 Controller unit

Claims (7)

A linearly-shaped first part, a loop-shaped second part adjacent to the first part, and a circular third part adjacent to the second part are arranged in series,
The third part is an end of the signal line, and is arranged in parallel with the first part ,
The first part has a convex part corresponding to the position of the third part .   The magnetic sensor according to claim 1, wherein the second portion includes a portion having a relatively wide signal line width and a narrow portion.   A first region having a shape corresponding to the first portion; a second region corresponding to the second portion and having a width exceeding the width of the first region; and a first region corresponding to the third portion. The magnetic sensor according to claim 1, further comprising a ground line having a third region formed in a manner of overlapping with the region. The magnetic sensor according to claim 3 , wherein the third region is formed so as to overlap with the second region. The magnetic sensor according to claim 3 , wherein the third portion is formed at a position eccentric with respect to a center position in the width direction of the first region.   A probe to which the magnetic sensor according to claim 1 is attached.   An EMC test detection apparatus comprising: the magnetic sensor according to claim 1; a probe to which the magnetic sensor is attached; and a processing unit that processes a signal from the magnetic sensor.