Specification
Patent application title: GSR sensor element
Technical field
[0001]
In the present invention, for a GSR sensor element having only one magnetic wire in one coil, a pair of magnetic wires having opposite current directions are disposed in one coil to achieve high sensitivity and low consumption. The present invention relates to technology for enabling power conversion.
Background art
[0002]
　Catheterization is widespread, but X-ray exposure, excessive injection of contrast media, and the level of skill of the physician are problematic. As a measure to solve that, it is desirable to incorporate a magnetic sensor into a catheter, measure the position and orientation of the catheter tip, and use that value to establish a remote control catheter treatment.
[0003]
However, the GSR sensor disclosed in Patent Document 1 is not sufficient in terms of linearity, sensitivity, small size, and power consumption.
That is, the use of rising pulse detection has problems with linearity, and the use of falling pulse detection has problems with sensitivity and power consumption, making it difficult to miniaturize the device ASIC.
In addition, if the size of the element is reduced, the sensitivity is reduced, and it is difficult to achieve a significant size reduction. There was a need to solve the above problems.
[0004]
The present invention, despite the use of rising pulse detection, ensures excellent linearity to improve sensitivity and power consumption. In addition, the device can be miniaturized by significantly improving the sensitivity. By reducing the power consumption, it is also possible to reduce the capacitance of the ASIC and to miniaturize the ASIC.
Prior art documents
Patent document
[0005]
Patent Document 1: Patent No. 5839527
Disclosure of the invention
Problems that the Invention is to Solve
[0006]
In the GSR sensor, installing two magnetic wires in one coil doubles the sensitivity, and adopting rising pulse detection can reduce pulse power consumption to 1/10 from 0.4 mW to 0.04 mW. , Conventionally known.
Here, the GSR sensor is an ultra-sensitive micro magnetic sensor based on ultra-fast spin rotation effect (GHz Spin Rotation effect).
However, the output voltage of the GSR sensor element is derived from two voltages: a voltage induced by pulse current (hereinafter referred to as induced voltage) and a voltage outputted in proportion to the magnetic field strength of the external magnetic field (hereinafter referred to as magnetic field voltage). It has become. Furthermore, the magnetic field changes the resistance of the magnetic wire, which affects the change of the wire voltage and the induced voltage.
In the falling pulse detection, the peak time tm of the magnetic field voltage and the peak time ti of the induction voltage are separated, and the induction voltage is sufficiently attenuated at the time tm (FIG. 7).
On the other hand, in rising pulse detection, tm and ti are close, and at time tm, the induced voltage has a considerable magnitude, and fluctuations due to the magnetic field can not be ignored (FIG. 8). It is an object of the present invention to remove the induced voltage from the output voltage of the GSR element and to realize a rising pulse detection type GSR sensor.
Means to solve the problem
[0007]
As a result of intensive studies on the above technical problems, the inventor has confirmed that the induced voltage is opposite in polarity to the direction of the current flowing through the magnetic wire. Furthermore, when two magnetic wires in which current flows in the opposite direction flows in one coil, the induced voltage is canceled and the technical idea of ​​the present invention can be detected that only the voltage proportional to the magnetic field can be detected. The
[0008]
A coil of a typical size of one magnetic wire GSR sensor element has a groove width of 20 μm and a coil width of 40 μm. The groove width of the GSR sensor element of two magnetic wires is 40 μm, a separation wall is provided at the center, two magnetic wires are disposed, and the coil width is 50 μm. As for the size of the GSR sensor element, one magnetic wire and two magnetic wires are almost the same.
[0009]
There are three types of structures as elements.
　One is a type in which two magnetic wires are arranged in a groove deeper than the magnetic wire, and the lower coil has a concave shape and the upper coil has a planar shape. The second type is a type in which two magnetic wires are arranged in a shallow groove about half the diameter of the magnetic wire. The lower coil has a concave shape and the upper coil has a convex shape.
The third type is a type in which a wedge-shaped guide is formed on a flat surface, and a total of two magnetic wires are disposed therein, the lower coil has a planar shape, and the upper coil has a convex shape.
　In either type of construction, a separation wall is provided between the two magnetic wires.
[0010]
　The lower coil and the upper coil are disposed at a half pitch offset, and are electrically connected to each other at the joint surface on the planar substrate of the two to form a spiral coil. The two coil ends are each connected to two coil electrodes.
[0011]
　　For the insulation between the magnetic wire and the coil, the method of adopting the magnetic wire coated with the insulating material, the method of inserting the magnetic wire in the insulating resist embedded in the groove, and the insulating method combining the both are available. is there. In order to ensure insulation, it is preferable to use an insulating coated magnetic wire.
　At the end of the magnetic wire, a metal portion of the magnetic wire was exposed from the insulating material, and a wire was provided for electrical connection with the wire electrode.
[0012]
　The output of the GSR sensor element using two magnetic wires can maintain excellent linearity even if rising pulse detection is adopted because only the magnetic field voltage is proportional to the magnetic field.
　The output voltage of the rising pulse detection is 2.5 times the output voltage of the falling detection. And since it consists of two magnetic wires, an output voltage of 5 times can be obtained. This means that since the number of turns N of the coil can be reduced to 1⁄5, the coil length of the element can be shortened to 1⁄5, and the element can be miniaturized.
[0013]
　Furthermore, the pulse width of the pulse current can be made sufficiently long, for example, 10 ns to 1 ns or less, as the rising edge needs to be detected. Thereby, the power consumption of the pulse current can be reduced to 1/10 or less.
[0014]
　The GSR sensor ASIC incorporates a capacitor for power storage for pulse current transmission. Its size accounts for 50% of ASICs. If the capacitor size can be reduced to 1/10, then the size of the ASIC can be reduced to almost half.
Effect of the invention
[0015]
　The GSR sensor element, in which two magnetic wires are arranged in one coil, eliminates the induced voltage component of the coil voltage to improve the linearity of the magnetic field dependency of the output voltage of the rising pulse detection and at the same time the sensitivity (unit The output voltage per 1 G of magnetic field strength can be increased five times, and the power consumption of the pulse current can be reduced to 1/10 or less. As a result, the device size and ASIC size can be reduced under the condition of the same output voltage.
Brief description of the drawings
[0016]
FIG. 1 is a front conceptual view showing GSR sensor elements of the embodiment and examples.
2A is a cross-sectional view taken along the line A1-A2 of FIG. 1 showing the GSR sensor element of the embodiment.
2B is a cross-sectional view taken along line A3-A4 of FIG. 1 showing the GSR sensor element of the embodiment.
2C is a cross-sectional view taken along line A5-A6 of FIG. 1 showing the GSR sensor element of the embodiment.
FIG. 3 is a cross-sectional view of another type (concave shape) of the GSR sensor element of the embodiment.
FIG. 4 is a cross-sectional view of another type (convex shape) of the GSR sensor element of the embodiment.
FIG. 5 is a block circuit diagram showing an electronic circuit of the GSR sensor in the embodiment.
FIG. 6 is a characteristic diagram of external magnetic field versus output voltage of the GSR sensor of the example and the magnetic sensor in the comparative example.
FIG. 7 is a transition diagram of temporal changes in magnetic field voltage and induced voltage in falling pulse detection.
FIG. 8 is a transition diagram of temporal changes in magnetic field voltage and induced voltage in rise pulse detection.
BEST MODE FOR CARRYING OUT THE INVENTION
[0017]
As shown in FIGS. 1, 2A, 2B and 2C, the GSR sensor element 1 according to the present embodiment has a magnetic wire 2 (21 and an insulating coated film of Co alloy, which is a magnetosensitive body) on the electrode wiring substrate 10. 22), consisting of a coil 3 (31 and 32) wound around the magnetic wire 2, four terminals (23 and 25 and 34 and 36).
[0018]
In the magnetic wire 2, two magnetic wires 21 and 22 separated by an insulating wall 41 are disposed in a groove 11 in the central portion of the substrate.
The upper portion of the magnetic wire 21 on the wire input electrode 26 (+) side illustrated on the right side of FIG. 1 is connected to the wire input electrode 26 (+) via the wire terminal 23 and the wire connection portion 21A (right portion in FIG. 2B )ing.
The lower portion of the magnetic wire 21 is connected at the lower portion of the magnetic wire 22 on the wire output electrode 27 (−) side via the wire bonding portion 22B illustrated on the left side via the wire bonding portion 21B and the inter-wire connection portion 23 (Fig. 2C).
The upper portion of the magnetic wire 22 is connected to the wire output electrode 27 (−) through the wire terminal 25 (left portion in FIG. 2B).
[0019]
Next, as shown in FIG. 2A, the coil 3 is composed of a lower coil 31, an upper coil 32, and a joint 33 for joining the two coils.
The lower coil 31 is formed in a concave shape in the groove 11 and on the substrate 10, and the upper coil 32 is formed over the substrate 10 through the insulating material 4 from the top to the side of the pair of magnetic wires 21 and 22. It is done.
The end of the lower coil 31 and the end of the upper coil 32 are connected on the substrate 10 by forming a joint 33.
The pair of magnetic wires 2 (21 and 22) is insulated by the insulating wall 41, and the magnetic wire 2 and the coil 3 are insulated by the insulating material 4.
[0020]
Therefore, the current flows downward in the right magnetic wire 21 and the current flows upward in the left magnetic wire 22, and the direction of the current in one coil becomes opposite through the insulating material, and the induced voltage Can offset
[0021]
In the present embodiment, a pair of magnetic wires consisting of two magnetic wires is installed in one coil so that the direction of the current is in the opposite direction via the insulating material. A magnetic wire consisting of a pair of wires may be installed.
[0022]
In the present embodiment, the magnetic wire is a magnetic wire coated with glass which is an insulating material, but a magnetic wire not coated with an insulating material may be used.
[0023]
In the present embodiment, as shown in FIG. 2A, as a structure of the element, the lower coil 31 has a concave shape in which two magnetic wires (21 and 22) are arranged in a shallow groove 11 about half the diameter of the magnetic wire The upper coil 32 has a convex shape.
[0024]
As another structure, as shown in FIG. 3, the lower coil 31 has a concave shape in which two magnetic wires (21 and 22) are disposed in a groove 11 deeper than the magnetic wire 2, and the upper coil 32 It is a planar shape. Also, as shown in FIG. 4, the third forms a wedge-shaped guide on a flat surface, in which two magnetic wires (21 and 22) are disposed one by one, and the lower coil 31 is flat. In shape, the upper coil 32 is convex.
[0025]
A separation wall is provided between the two magnetic wires (21 and 22) in either type of construction. A joint portion 33 for joining the end of the lower coil 31 and the end of the upper coil 32 is provided to form the coil 3.
[0026]
Next, a method of manufacturing the GSR sensor element will be described.
　The electrode wiring substrate 10 is made of a Si substrate coated with a SiN film. The magnetic wire 2 uses an amorphous wire with a glass insulating film and a diameter of 1 to 20 μm and a length of 0.07 to 1.0 mm.
First, the element 1 has a width of 0.25 mm, and a groove 11 with a width of 20 to 60 μm and a depth of 2 to 20 μm is formed in the central portion.
[0027]
Next, electrode wiring is performed along the groove 11 on the lower coil 31 and the substrate surface. Thereafter, an insulating separation wall 41 is formed at the central portion of the groove 11 to form two groove shapes, in which two magnetic wires 21 and 22 are respectively disposed. Thereafter, an insulating resist is applied to the entire surface of the substrate. The top of the two magnetic wires (21 and 22) is thinly coated. The upper coil 32 is formed there by photolithography.
The end portions of the lower coil 31 and the upper coil 32 form joint portions 33 joined in a cross-over manner on the plane of the substrate to form a coil 3 with a coil pitch of 2 to 10 μm. The coil terminal 34 is connected to the coil output electrode 35 (+), and the coil terminal 35 is connected to the coil ground electrode 37 (−).
[0028]
For the four ends of the two magnetic wires, the glass of the insulating coating is removed, and at one of the two ends, the wire terminal 23 and the connection portion 21A are formed by metal deposition, and the wire input electrode 26 (+) In addition, the wire terminal 25 and the connection portion 22A are formed by metal deposition, and the electrical connection to the wire ground electrode 27 (-) is made.
Then, metal deposition (21 B and 22 B) is performed on the other two ends, and a connecting portion 23 connecting the two ends is formed by metal deposition.
In this manner, the wire input electrode 26 (+) to the wire ground electrode 27 (−) serve as a wire for passing a pulse current.
[0029]
According to this embodiment, the output voltage exhibits a sine wave output characteristic with respect to the magnetic field H, the measurement range is ± 3 to 90 G, and the linearity is very good at 0.3% or less.
The sensitivity is 50 to 2000 mV / G, which is five times that of a GSR sensor element consisting of the same magnetic wire length.
The pulse power consumption is 0.3 mW (0.15 mA).
Example
[0030]
Hereinafter, the GSR sensor element according to the embodiment of the present invention will be described below with reference to FIG. 1, FIG. 5 and FIG.　
[0031]
The substrate 10 is made of a Si substrate and is insulating coated with SiN, and its size is 0.2 mm in length, 0.2 mm in width, and 0.2 mm in height. The magnetic wire 2 is a glass-coated amorphous wire with a diameter of 10 μm using a CoFeSiB-based alloy and has a length of 0.20 mm.
[0032]
The groove 11 of the substrate 10 has a width of 40 μm and a depth of 6 μm. The size of the separation wall 41 made of the insulating resist in the groove 11 is 2 μm in width and 6 μm in height.
[0033]
The coil 3 has a width of 50 μm and a height of 14 μm, an average inner diameter (diameter of a circle equal to the cross section of the coil formed by the height and width) of 26 μm, a coil pitch of 5 μm, and 28 coil turns. .
[0034]
Next, the characteristics of the GSR sensor element 1 were evaluated using the electronic circuit for the MI sensor shown in FIG.
The electronic circuit 5 comprises a pulse generator 51, a signal processing circuit 52 having the GSR sensor element 1 and a buffer circuit 53. The signal is a pulse signal with an intensity of 100 mA corresponding to 1 GHz, and a pulse current with a rise time of 0.5 nsec, a pulse width of 1 nsec, and a fall time of 0.5 nsec is input.
The pulse signal is input to the amorphous wire 2. During the application of the pulse, a voltage proportional to the external magnetic field is generated in the electromagnetic coil 3 to perform rise pulse detection.
[0035]
The signal processing circuit 52 inputs the voltage generated in the coil 3 to the buffer circuit 53, and the output from the buffer circuit 53 is input to the sample hold circuit 56 via the electronic switch 55. The timing of opening and closing the electronic switch 55 is adjusted by the detection timing adjustment circuit 54 so as to detect the rising pulse signal at an appropriate timing, and the voltage at that time is sampled and held. Thereafter, the voltage is amplified by an amplifier 57 to a predetermined voltage.
[0036]
The sensor output from the electronic circuit is shown in FIG. The horizontal axis in FIG. 6 is the magnitude of the external magnetic field, and the vertical axis is the sensor output voltage.
The sensor output shows a sine wave output characteristic and exhibits linearity in the range of ± 90 G by arc sin conversion. Non-linearity is 0.3%. The sensitivity is 210 mV / G.
[0037]
MI element (length 0.6 mm, width 0.3 mm) used for commercial product AMI 306 as comparative example 1 and GSR sensor element for automobile (length 0.15 mm, width 0.20 mm) as comparative example 2 It measured and evaluated with the same electronic circuit. The results are shown in Comparative Examples 1 and 2 of FIG.
The sensor output voltage at a magnetic field strength of 90 Oe is 0.1 V for the MI sensor of Comparative Example 1 and 0.3 V for the GSR sensor of Comparative Example 2, and the GSR sensor of the present invention is extremely excellent at 1.5 V. The sensitivity is obtained.
Industrial applicability
[0038]
As described above, the GSR sensor element of the present invention is very compact and has high sensitivity. Therefore, the GSR sensor comprising this element can be incorporated in a catheter because of its extremely high sensitivity, small size, and low power consumption, and can be applied to a wide range of fields such as smartphones.
Explanation of sign
[0039]
1: GSR sensor element plate, 10: substrate, 11: groove on substrate
2: magnetic wire, 21: one of a pair of magnetic wires, 22: another one of a pair of magnetic wires,
21A: wire terminal and wire Connection part with input electrode (+)
22A: Connection part between wire terminal and wire output electrode (-)
21B: Wire connection part 22B: Wire connection part
23: Terminal of magnetic wire 24: Connection between wires Part 25: Magnetic wire terminal
26: Wire input electrode (+), 27: Wire output electrode (-)
3: coil, 31: lower coil, 32: upper coil, 33: joint part
4: insulating material, 41 : isolating wall
5: electronic circuit
51: pulse oscillator 52: signal processing circuit 53: buffer circuit 54: detection timing
grayed adjusting circuit, 55: electronic switch, 56: sample-and-hold circuit, 57: amplifier
The scope of the claims
[Claim 1]
A GSR sensor element in which a magnetic wire as a magnetosensitive body and a coil wound around it and four terminals for connecting with an external integrated circuit are formed on an electrode wiring substrate in the
coil. A pair of magnetic wires having opposite directions of current flow are installed through an insulating material, the
coil comprises a lower portion of the coil, an upper portion of the coil, and a joint portion connecting the two, and the
pair of magnetic wires is A GSR sensor element characterized by being separated by an insulating wall in a coil.
[Claim 2]
The
GSR sensor element according to claim 1, wherein the magnetic wire comprises a plurality of pairs.
[Claim 3]
The
GSR sensor element according to claim 1, wherein the outer periphery of the magnetic wire is coated with an insulating material.
[Claim 4]
The
coil according to claim 1, wherein the coil comprises a concave coil lower portion, a convex coil upper portion, and a joint portion connecting the two, and the pair of magnetic wires are coated with the coil lower wiring and coated with an insulating material. It is embedded in a groove of a substrate and fixed with an insulating resin having an adhesive function and a resist function, and
the upper portions of the pair of magnetic wires are thinly covered with the surface tension of the insulating resin to perform the coil upper wiring A GSR sensor element characterized in that the coil electrically connects the end of the lower portion of the coil and the end of the upper portion of the coil.
[Claim 5]
The coil comprises a concave coil lower portion, a flat coil upper portion, and a joint portion connecting the two, and the pair of magnetic wires are provided with the coil lower wiring and are interposed in grooves of the substrate in which an insulating material is embedded. GSR characterized in that the coil upper wiring is provided on the upper surface of the groove, and the joint electrically connects an end of the lower portion of the coil and an end of the upper portion of the coil to form a coil. Sensor element.
[Claim 6]
The coil comprises a flat coil lower portion, a convex coil upper portion, and a joint portion connecting the two, and the pair of magnetic wires are made of insulating resin on the upper surface of the coil lower wire provided on the flat surface of the substrate. Fixing, side portions and upper portions of the pair of magnetic wires are covered with the insulating resin, the coil upper wiring is performed, and the joint electrically connects an end portion of the lower portion of the coil and an end portion of the upper portion of the coil A GSR sensor element characterized in that a coil is formed.