JPH02285212A - Displacement sensors and displacement sensor ICs - Google Patents

Abstract

PURPOSE:To obtain an output which linearly changes in proportion to the quantity of a displacement and obtain the same output voltage for the same quantity of the displacement by arranging two magnetic pole planes in a plane parallel to a semiconductor flake forming a magneto-electric transducer housed in an IC. CONSTITUTION:When an object whose displacement is to be detected and which is connected to a link arm 9 reciprocates in a direction shown by an arrow A, the link arm 9 rocks about an axis 9a while following a reciprocation. A rocking thus obtained is converted to the reciprocating motion of a slider 6 via rod 6a and the slider 6 slides in a housing 8. Thus a relative positions of a Hall IC 5 fixed to the housing 8 via a substrate 12 and the slider 6 change. When the relative positions change, the density of magnetic flux crossing a current supplied to the Hall IC 5, namely, the one effective to generate a voltage due to a Hall effect, in the magnetic flux formed by magnets 11a and 11b changes. As a result, a voltage outputted from the Hall IC 5 due to the Hall effect changes.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a displacement sensor and a displacement sensor IC, and particularly to a displacement sensor that can obtain a detection output that changes linearly with the displacement of a detected object. The present invention relates to a sensor and a displacement sensor IC used in the displacement sensor.

(Prior Art) When controlling the displacement amount of a linearly displacing moving object to a predetermined reference value, the displacement amount is detected by a displacement sensor, and the moving object is adjusted based on the deviation between this detection output and the reference value. The amount of displacement was controlled to be close to the reference value.

As the displacement sensor, for example, a differential transformer type sensor,
Alternatively, a magnetoelectric transducer type sensor such as a Hall element or a magnetoresistive element may be used.

In the differential transformer type sensor, the differentially wound primary (
By inserting an iron core into the center of the excitation coil and the secondary coil and applying a voltage to the primary coil, an induced voltage of a magnitude corresponding to the amount of displacement of the iron core is generated in the secondary coil. The amount of displacement of the iron core can be detected based on this induced voltage.

On the other hand, in a magnetoelectric transducer type sensor using a Hall element, for example, when a magnetic field is applied in a direction perpendicular to the current supplied to the Hall element, an output voltage corresponding to the strength of the magnetic field crossing the current is obtained. If a magnet that forms the magnetic field is attached to the moving object, the relative position of the moving object and the Hall element can be detected based on the output voltage of the Hall element, and the amount of displacement of the moving object can be detected from changes in this relative position. can.

(Problems to be Solved by the Invention) The above-described conventional technology had the following problems.

In a differential transformer type sensor, when the detection results are processed by a computer, it is necessary to convert the detected induced voltage into direct current, which makes the circuit for receiving the sensor output signal complicated.

On the other hand, a magnetoelectric transducer type sensor has the advantage of being able to obtain a direct current output.

However, in a magnetoelectric transducer type sensor, when the distance between the magnet, that is, the moving object, and the magnetoelectric transducer (Hall element) changes, the output voltage changes in almost inverse proportion to the square of the distance between the Hall element and the magnet, and the output voltage changes linearly. Another problem is that it does not change.

That is, as a sensor for controlling the amount of displacement of a moving object, it is desirable that its output voltage changes linearly in accordance with the amount of displacement. For this purpose, the output of the Hall element must be corrected to obtain a signal proportional to the amount of displacement of the moving body, so in this case as well, the problem is that the circuit becomes complicated, similar to the differential transformer type sensor described above. was there.

Furthermore, in the magnetoelectric transducer type sensor, the gap between the magnet and the magnetoelectric transducer may be affected due to misalignment, variations in the magnetic force of the magnet, and variations in sensitivity of the magnetoelectric transducer. However, there was a problem in that the same output voltage could not always be obtained for the same amount of displacement.

Among the above-mentioned problems, the following measures may be taken to deal with variations in sensitivity of magnetoelectric conversion elements.

FIGS. 7 and 8 are diagrams for explaining the output adjustment means of a Hall IC incorporating a Hall element as a magnetoelectric conversion element.

In FIG. 7, the output terminal of Hall element 1 is connected to amplifier 2. In FIG. Between one input terminal and the output terminal of the amplifier 2, resistors "1" to "5" having different resistance values are connected in series as amplification factor setting resistors, and fuses f1 to f5 are connected to these resistors r1 to r5. are connected in parallel.

In addition, resistors r6 to ``8'' with different resistance values are connected in series between the other input terminal and ground as offset voltage setting resistors, and fuses f6 to f8 are connected to these resistors ``6 to ``8, respectively. connected in parallel.

In the above configuration, a predetermined magnetic field is applied to the Hall element 1, the output of the amplifier 2 is checked, and in order to match the output characteristics with the reference characteristics, one of the fuses f1 to f8 is blown, and each fuse is used to set the amplification factor. Selected resistor and offset voltage setting resistor.

Both ends of the fuse are formed as follows. In FIG. 8, a pad portion 4 with which a voltage application probe can be contacted is provided at the end of each of the fuses f1 to f3. After checking the output of the amplifier 2, the probes are applied to the pads at both ends of the fuse to be blown, and a pulse voltage is applied to blow the fuse.

Such sensitivity adjustment means compensates for variations in characteristics between the Hall element 1 and the amplifier 2, and eliminates variations in the output of the Hall IC.

However, since the sensitivity adjustment means is implemented at the stage of a pair of Hall IC chips or a wafer, this Hall IC may be combined with an unspecified magnet and used as a sensor, or this Hall IC and this In a situation where the gap between the magnets cannot be maintained accurately, there is a problem in that even if the sensitivity is adjusted by the Hall IC alone, the output will vary when assembled as a sensor.

The present invention solves the above-mentioned problems and provides a displacement sensor that can provide an output that changes linearly in proportion to the amount of displacement, and that can always provide the same output voltage for the same amount of displacement, and a displacement sensor that can be used therefor. The object of the present invention is to provide an IC for a displacement sensor.

(Means and effects for solving the problems) The present invention for solving the above-mentioned problems and achieving the objects includes a magnetoelectric conversion IC fixed to either a fixed part or a moving part,
Two magnetic pole surfaces are provided on the other of the fixed part and the moving part and are arranged in a plane parallel to a semiconductor thin piece surface forming a magnetoelectric transducer incorporated in the IC, and the polarities of the magnetic pole surfaces are opposite to each other. It is characterized by having magnets arranged so that

Further, the IC includes a plurality of resistors for adjusting the output characteristics of the IC to desired characteristics, and a means connected in parallel to these resistors to switch these resistors into a short-circuited state or a non-shorted state. , both ends of these switching means are connected to IC
The second feature is that it is exposed to the outside from the package as a part of the terminal.

In the present invention having the above configuration, the angle at which the current being supplied to the IC is traversed by the magnetic flux formed between the two magnets changes depending on the relative position of the magnetoelectric conversion IC and the two magnets. That is, the perpendicular component of the magnetic field with respect to the current changes, and the magnetic flux density that effectively acts to produce an output voltage in the IC changes. As a result, a voltage that varies linearly depending on the relative position between the fixed part and the moving part can be extracted as a sensor output.

Further, according to the second feature of the present invention, after configuring a sensor by incorporating an IC together with a magnet, a signal for switching the switching means is supplied from a terminal connected to the switching means and exposed to the outside. By switching the switching means and selecting the resistance value, the output characteristics of the IC can be adjusted.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view of a stroke sensor that is an embodiment of the present invention.

The slider 6 is disposed within the housing 8 so as to be slidable in the left-right direction in FIG. A rod 6a extending perpendicularly to the sliding direction of the slider 6 is provided at one end of the slider 6, and the rod 6a is engaged with a notch at the end of the link arm 9.

The slider 6 is powered by a coil spring 10 interposed between the other end of the slider 6 and the inner surface of the housing 8.
In FIG. 1, it is biased to the right. Since the slider 6 is biased in the rightward direction, a rotational force in the direction of the guide needle always acts on the link arm 9 about the shaft 9a.

That is, due to the action of the coil spring 10, the play in the engagement portion between the rod 6a and the link arm 9, the play between the shaft 9a and the bearing portion (not shown), and the play in the link arm 9 are reduced.
and the displacement detection object (
(not shown) is absorbed, and the movement of the link arm 9 rotating about the shaft 9a is accurately transmitted to the slider 6.

A magnet 11a is provided in the recess 6b provided in the slider 6,
llb is placed. These magnets 11a and llb are
Each magnetic pole surface is arranged to be parallel to a semiconductor thin piece surface forming a Hall element built in the IC 5, and the polarities of the sides facing the semiconductor thin piece surface are opposite to each other.

A board 12 is fixed to the upper part of the housing 8 by screws 13 and 14, and a Hall IC 5 is mounted on the lower surface of the board 12, that is, on the side facing the magnets 11a and 11b. The supply of current to the Hall IC 5 and the extraction of the output voltage are performed via the contactor 7 drawn out to the connector portion 15.

The sensor of this embodiment configured as described above operates as follows.

When the displacement detection object connected to link arm 9 reciprocates in the direction of arrow A, link arm 9 follows this reciprocating motion and swings around axis 9a.

That is, the link arm 9 swings between the position shown by the solid line and the position shown by the chain line. This rocking motion is converted into a reciprocating motion of the slider 6 via the rod 6a, and the slider 6 slides within the housing 8.

As the slider 6 slides within the housing 8,
Hall IC fixed to housing 8 via substrate 12
The relative position between the slider 5 and the slider 6 changes. When this relative position changes, the magnetic flux density, which crosses the current supplied to the Hall IC 5 (hereinafter simply referred to as "crossing the Hall IC 5") among the magnetic fluxes formed by the magnets 11a and 11b, that is, generates a voltage due to the Hall effect. The effective magnetic flux density for this changes. As a result, the voltage output from the Hall IC 5 also changes due to the Hall effect.

FIG. 2 shows changes in the output of the Hall IC 5.

This will be explained in detail with reference to FIGS. 3 and 4.

FIG. 2 shows the state of the magnetic field crossing the Hall IC 5. In addition, Fig. i3 shows an example of the relationship between the magnetic flux density and the output of the Hall IC 5, and Fig. 4 shows the relationship between the Hall IC 5 and the magnet 1.
An example of the relationship between the amount of change (stroke) in the positional relationship of 1a and flb and the output of the Hall IC 5 is shown.

As shown in FIG. 2, the magnet 11 that crosses the Hall IC 5
The density of the magnetic flux 11c of a, llb changes depending on the relative position of the Hall IC 5 and the magnets 11a, llb.

As shown in the figure, the Hall IC 5 is connected to the magnets 11a and llb.
When the magnetic flux 11c that crosses the Hall IC 5 is located in the middle of the magnet 1, the magnetic flux 11c that crosses the Hall IC
Position near either 1a or llb (5a or 5
At position b), the magnetic flux 11c crossing the Hall IC 5 increases.

By changing the density of the magnetic flux 1Lc crossing the Hall IC 5 in this way, the Hall IC 5
output changes. In the figure, a bias is applied so that an output of 2.5V is obtained from the Hall IC when the magnetic flux density is θ Gauss. Hall IC5 is magnet 11b
The magnetic flux density crossing the Hall IC 5 increases as it approaches the N pole of the Hall IC 5, and the Hall IC output increases.

Similarly, as the Hall IC 5 approaches the S pole of the magnet 11a, the magnetic flux density across the Hall IC 5 increases. However, as the magnetic flux density increases, the output appearing at the terminal of the Hall IC 5 has a sign opposite to that of the Hall IC output, which increases as the Hall IC 5 approaches the N pole of the magnet 11b. It changes in the direction of gradually decreasing from 5V.

The magnetic flux density change is caused by the Hall IC 5 and the magnets 11a, ll.
This change in relative position is reflected by the slider 6 to which the magnets 11a and llb are attached.
When this is made to correspond to the stroke of , a relationship as shown in FIG. 4 is obtained.

In this way, a Hall IC output that changes linearly as the stroke of the slider 6 changes is obtained.

Next, a description will be given of means for adjusting the output of the Hall IC 5 so that it always remains constant for a given amount of change in stroke.

Figure 5(a) shows the Hall element 1° amplifier 2 shown in Figure 7.
．． FIG. 5(b) shows the terminal numbers of the Hall IC 5 shown in FIG. 5(a) and the fuses f1 to f.
8 is a diagram showing the correspondence with 8.

As shown in the figure, the ends of each fuse f1 to f8 are connected to terminals p2 to
Since the terminals p2 to p are exposed to the outside through the pH
A voltage is applied to any one of fuses f1 to f8 to blow out a desired fuse.

Therefore, after incorporating this Hall IC 5 into the stroke sensor shown in FIG. 1, check the output and
Apply voltage from a desired terminal of H to fuse f1~
By fusing either f8, the output can be adjusted to the desired characteristics.

In FIG. 6, amplifier 2. Resistance “1~r8.Fuse f1
An example is shown in which ~f8 and the Hall element 1 are housed in two separate packages. In the figure, the package FAI has the Hall element 1 built-in, and the package PA2 has the amplifiers 2. Resistance rl-r8. An amplifier circuit with a trimming function is built in, which is comprised of fuses fl to f8. In the figure, the terminals p1 to p12 are connected in the same manner as shown in FIG. 5, except for the terminal p12.

Also in the embodiment shown in FIG. 6, by applying a voltage to any one of the terminals p1 to pH to flow a current sufficient to melt the fuse, the desired fuse is blown.
An appropriate amplification factor and offset voltage are changed to adjust the output of the Hall element 1.

By dividing the package into two in this way,
If there is no space to store the Hall IC 5 within the sensor, a small package F containing only the Hall element 1 is available.
The AI can be placed within the sensor and the package PA2 can be placed separately.

In addition, components in which only the Hall element is built into a package are commercially available as standard products, so they are highly versatile.

As described above, according to this embodiment, the output of the Hall IC 5 changes linearly the amount of sliding of the slider 6, that is, the amount of displacement of the detected object connected to the link arm 9, in accordance with this amount of displacement. can be detected based on

Moreover, after the Hall IC 5 is incorporated into the sensor together with the magnets 11a and 11b, its output characteristics can be adjusted, so that the characteristics of the Hall element 1, amplifier 2, etc. that constitute the Hall IC 5, and the magnet 11a.

Even if there are variations in the magnetic force of the magnet 11b, or even if there is a positional shift between the Hall IC 5 and the magnets 11a and 11b when they are assembled, the output characteristics can be adjusted to the expected output characteristics.

In the embodiments described above, an example was shown in which the fuse connected in parallel to the resistor was fused to switch the resistor from a short-circuited state to a non-shorted state.

However, the resistor is not limited to being switched from a short-circuited state to a non-shorted state as described above, but may be configured to be switched from a non-shorted state to a shorted state.

By switching the resistor from a non-shorted state to a shorted state, Hall I
FIG. 9 shows an example in which the output characteristics of C5 are adjusted. In this figure, the same reference numerals as in FIG. 7 indicate the same or equivalent parts.

In the figure, Zener diodes ZDI to ZD8 are connected to resistors r1 to r8, respectively. The Zener voltages of these Zener diodes ZD1 to ZD8 are set to a value higher than the maximum voltage across the resistors. Since the Zener voltage is set high in this way, the Zener diode is not in a conductive state before output adjustment, so all the resistors r1 to r5 connected in series, or
Based on the resistance values of 6 to r8, the amplification factor 4 or offset voltage of the amplifier 2 is set.

When adjusting the output of the Hall IC by adjusting the setting value of this amplification factor or offset voltage, the Zener current is applied from the terminal of the Hall IC connected to both ends of each Zener diode ZDI to ZD8 to the desired Zener diode ZDI to ZD8. A voltage that allows the flow of the Zener diode, that is, a Zener voltage, is applied to turn on any Zener diode among the Zener diodes ZDI to ZD8, and short-circuit the resistor connected in parallel with the Zener diode.

In this way, by selecting the resistor, the amplification factor and offset voltage are adjusted, and the output of the Hall IC is adjusted.

In each of the above embodiments, a Hall IC is shown in which a resistor for setting the amplification factor and a resistor for setting the offset voltage are connected in series, and a fuse is connected in parallel to these resistors. Resistors with different resistance values may be connected in parallel, and a fuse may be connected in series with these resistors.

In short, since both ends of the fuse are connected to the terminals exposed outside the package, the fuse can be easily blown out even after the Hall IC is incorporated into the sensor. The amplification factor or offset voltage may be set by selecting any resistor among the resistors.

In this embodiment, a stroke sensor has been described as an example of a displacement sensor, but this is not limited to cases in which a slider, that is, an object to be detected for displacement moves back and forth, but also applies to cases in which a moving object is displaced only in one direction. The present invention can also be applied to a displacement sensor that detects the amount of displacement of a moving body.

Furthermore, in this embodiment, an example is shown in which two magnets are used to generate a magnetic flux that crosses the Hall IC. If you use magnets, the number of magnets is 2.
Not limited to.

In addition, although this embodiment has described an example in which a Hall element is used as the magnetoelectric transducer element, it is not limited to the Hall element, and other magnetoelectric transducer elements such as a magnetoresistive element may also be applied to the displacement sensor of the present invention. can.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

(1) Since the IC outputs a DC voltage that changes linearly in response to the amount of displacement of the moving body, when the output of this IC is processed by a computer, the receiving circuit can be simplified.

(2) Since the output characteristics can be adjusted after incorporating the IC into the sensor, variations from sensor to sensor are eliminated, and a constant amount of displacement can be detected from a constant output. As a result, there is compatibility when multiple sensors are manufactured.

[Brief explanation of drawings]

Figure 1 is a sectional view showing an embodiment of the present invention, Figure 2 is a diagram showing the state of magnetic flux crossing the Hall IC, Figure 3 is a diagram showing the relationship between magnetic flux density and Hall IC output, and Figure 4 is the stroke of the slider. Relationship diagram between amount of change and Hall IC output, Figure 5 (axis) is a plan view of the Hall IC, Figure 5 (b) is a terminal connection diagram of the Hall IC, Figure 6 is a Hall element built-in package and amplifier with trimming function. A connection diagram with a built-in circuit package, FIG. 7 is a circuit diagram of a Hall IC with an output adjustment means, FIG. 8 is a diagram showing the main part of FIG. 7, and FIG. 9 is a circuit diagram of a Hall IC with an output adjustment means. FIG. 3 is a circuit diagram of an example. DESCRIPTION OF SYMBOLS 1... Hall element, 2... Amplifier, 4... Pad, 5... Hall IC, 6... Slider, 6a...
Rod, 8...Housing, 9...Link arm,
9a...shaft, 10...coil spring, lla, llb
...Magnet, 12...Substrate, r1 to r8...Resistance,
f1-f8...Fuse, p1-p12...Terminal,
Pl...Package with built-in Hall element, P2...Package with built-in amplifier circuit with trimming function, ZDI~ZD8
... Zener diode agent Patent attorney Michito Hiraki and 1 other person - -! -Utsuguya

Claims (7)

[Claims] (1) A magnetoelectric conversion element, an amplifier for amplifying the output of the magnetoelectric conversion element, and multiple resistors for setting the amplification factor of this amplifier; connected in parallel to these multiple resistors, and short-circuiting each resistor. - An IC for a displacement sensor, characterized in that it is equipped with switching means for setting either non-short-circuited state, and both ends of these switching means are connected to terminals exposed to the outside from the IC package. (2) A plurality of resistors for setting the offset voltage of the amplifier, and a switching means connected in parallel to the plurality of resistors to put each resistor in a short-circuited state or a non-short-circuited state. The IC for a displacement sensor according to claim 1. (3) Of the magnetoelectric transducer, amplifier, resistor, and switching means that are the components of an IC, a first package that contains at least the magnetoelectric transducer and a second package that contains the remainder of the components. 3. The displacement sensor IC according to claim 1, further comprising: (4) having an IC fixed to either one of the fixed part and the moving part, and a magnet provided to the other of the fixed part and the moving part to generate a magnetic field that crosses the current supplied to the IC; In a displacement sensor that detects the amount of displacement of the moving part based on an output of the IC that changes in accordance with a change in the relative position of the magnet and the IC, the thin surface of a semiconductor forming a magnetoelectric conversion element built in the IC is A displacement sensor comprising a magnet in which two magnetic pole faces are arranged in parallel planes so that their polarities are opposite to each other. (5) The displacement sensor according to claim 4, wherein the IC is the displacement sensor IC according to claim 1, 2, or 3. (6) The displacement sensor IC according to claim 1 or 2, wherein the switching means is a fuse that switches the resistor from a short-circuited state to a non-shorted state. (7) The IC for a displacement sensor according to claim 1 or 2, wherein the switching means is a Zener diode that switches the resistor from a non-shorted state to a shorted state.