JPS6117015A - Detector of number of rotation, speed and the like - Google Patents

Abstract

PURPOSE:To perform highly reliable detection, by providing a magnetic flux generating part and an electromotive-force generating element utilizing the magnetic flux generating part in a ralatively moving body, and applying the output of the electromotive-force generating element to an element, which modulates light intensity, through a clip circuit. CONSTITUTION:For example, a permanent magnet 11 is embedded at the periphery of a disk 10, which is fixed to the output shaft of a motor. The magnet 11 performs circular movement accompanied by the rotation of the disk 10. A coil 30 is provided at an arbitrary point on the locus of the magnet 11 so as to face the magnet 11a in the vicinity of the magnet 11a, which has arrived at said arbitrary point. A light-intensity modulating element includes a Mach-Zehnder type light guide 25, which is formed on a substrate 20. The light guide 25 is composed of an input light guide part 23, branched light guide parts 21 and 22 and an output light guide part 24. Both ends of the coil 30 are connected to electrodes 31 and 32, which are formed on the parts 21 and 22, through a clip circuit 33. Light from a light source is guided to the light guide 25 through an optical fiber 41. By the change in intensity of the light from the optical fiber 42, the number of rotation of the disk 10 can be detected highly reliably.

Description

[Detailed Description of the Invention] Background of the Invention [Technical Field of the Invention] Speed, angular position, speed, period, position of an object moving periodically on a fixed course, speed of other objects, etc. The present invention relates to a detection device using a signal.

[Description of prior art]

Optical transmission has the excellent feature of not being affected by electromagnetic noise, so it is suitable for data transmission in environments with a lot of electromagnetic noise. Since optical fibers allow optical data transmission with low loss, data transmission over relatively long distances can also be performed. If the data to be optically transmitted is some kind of measurement data, such as the number of revolutions, it is preferable to perform the measurement or detection in the form of light and then optically transmit the measurement data as it is through an optical fiber. This is where the use of optical sensors and optical fiber sensors comes into play. By combining detection by optical sensors and optical fiber transmission, highly reliable measurement and long-distance transmission are possible even in environments with a lot of electromagnetic noise, creating a remote measurement system that uses light. .

Now, in a typical optical sensor for measuring rotational speed, rotational speed, angular velocity, etc., a hole is drilled in a part of the periphery of the opaque rotary plate, and a pair of optical fibers are inserted into the hole from both sides. There is something that is opposite. Light from a light source is emitted from one optical fiber and enters the other optical fiber.

As the rotating plate rotates, when the hole reaches the position of the optical fiber, light passes through this hole, and when the other portion faces the optical fiber, the light is blocked. Then, an on/off signal corresponding to the rotation of the rotating plate is obtained in the other optical fiber.

However, in such an optical sensor, since the light emitted from one of the optical fibers is spread out, only a small portion of the light enters the other optical fiber, and the intensity of the resulting photodetection signal decreases. It has the disadvantage of being low. In order to eliminate this drawback, it is necessary to converge the light emitted from one of the optical fibers using a lens. Since a lens is required, the configuration becomes complicated and strict alignment of the optical axis is required. In addition, there is a high possibility that the optical axis will shift due to vibration or the like.

Summary of the Invention [Object of the Invention] This invention utilizes the advantages of optical measurement, which enable highly reliable measurement and low-loss long-distance transmission even under electromagnetic noise, while eliminating the hassle of optical axis alignment. It is an object of the present invention to provide a detection device for detecting rotational speed, speed, etc., which does not require additional work and does not cause a situation in which measurements cannot be made due to optical axis deviation.

[Structure, operation, and effects of the invention]

The device for detecting rotational speed, speed, etc. according to the present invention is fixed to a relatively moving object, such as a rotating body, with a magnetic flux generating part, such as a permanent magnet, and the other object, such as a fixed member, and the magnetic flux generating part is fixed to the other object, such as a fixed member. An element that generates an electromotive force by passing relatively near it, such as a coil, a clip circuit connected between both terminals of the electromotive force generating element, and the output voltage of the clip circuit are applied, and this electrical application causes the light source to It is characterized by comprising an element that modulates the intensity of the guided light, and means for creating information regarding the movement of the moving object, such as rotation speed and speed data, from changes in the modulated light intensity.

It is preferable that the clipping circuit clips one of the positive and negative voltages generated in the electromotive force generating element and also clips a portion of the other voltage that exceeds a predetermined level.

Every time the magnetic flux generator passes near the electromotive force generating element,
The intensity of the light directed from the light source is modulated, eg, the intensity is increased or decreased. Therefore, by counting the number of light intensity modulations in a certain period of time, or
By measuring the time interval between two light intensity modulations, data on the rotational speed and speed of a moving object can be obtained.

Light from a light source is guided to a light intensity modulating element through an optical fiber, and output light (intensity modulated light) from this element is sent to an information generating means through an optical fiber. Since the optical fiber and the light intensity modulation element are easily connected using a known optical connector or the like, there is no need to align the optical axis using a lens as in the past, and of course there is no fear that the optical axis will shift.

The voltage generated by the electromotive force generating element is transferred to the second part by the clip circuit.
The (lower) limit level is clipped to a constant level (when the generated voltage exceeds the clip e level), and this constant electron is applied to the light intensity modulation element. Therefore, the light intensity modulation pattern by the light intensity modulation element is the same regardless of the level of the generated voltage. Therefore, since the information generating means only needs to process the same pattern of intensity modulated light, its configuration can be simplified.

Conventional magnetic wheel speed sensors have either a permanent magnet, a rotating plate fixed around its periphery, or a rotating plate with its own periphery magnetized.

This rotational speed sensor uses a magnetoelectric conversion element that responds to the magnetism of a rotating plate to extract an electrical signal representing the rotational speed. According to the present invention, the rotary plate of such a conventional magnetic N rotation speed sensor can be used as is and easily modified into an optical measurement and transmission system using an optical fiber.

DESCRIPTION OF EMBODIMENTS [Structure of rotational speed detection device] In FIG. 1, a disk is fixed at the center of a shaft whose rotational speed is to be detected, for example, the output shaft of a motor or a shaft connected thereto (as shown in the diagram), The disk tlO) rotates together with this axis. Around this disk 101, there is one ρ permanent magnet (]]) or a magnet embedded (dashed line (1) a)
A coil 60) is arranged so as to face the coils 60) near the coils 60), and is fixed in that position by a suitable fixing member.

The magnet (1) can also be provided on the circumferential surface of the disk 0 (1).In this case, the arrangement should be such that it interlinks as much as possible with the magnetic flux generated from the coil (this magnet (1)). Instead of installing a permanent magnet (1) on the disc (1o), the disc 00) itself is made of a ferromagnetic material, or a ferromagnetic ring is fitted around the disc, and the ferromagnetic material is It may also be magnetized.

The light intensity modulation element includes a Matsuhatsu-Enda type optical waveguide (c) formed on a crystal having an electro-optic effect, for example, a L i N b O3 crystal substrate. This Matsuhatsu Enda type optical waveguide part) is the input optical waveguide part (23
), 2 branched at equal angles from this optical waveguide partial force)
The two branched optical waveguide portions 01) (branches) and the output optical waveguide portion (24) where these optical waveguide portions Q1)
It consists of 1. A pair of electrodes 01) are placed so that a part of them is respectively placed on the branched optical waveguide portion 01).
E is formed on the substrate (20). Both ends of the coil circle are connected to a clip circuit -, and the output side of this clip circuit O9 is connected to the electrodes (31)' (321).The voltage induced in the coil field is connected to the clip circuit (33). clipped at the required level,
This voltage after being clipped is the electrode Gl) (32
It is applied for 1.

The clip circuit includes a series circuit of a diode field and a battery ■, a diode (36) connected in parallel with this series circuit and with opposite polarity to the diode (T), and these circuits connect a resistor (34). It is connected between both ends of the coil via. The voltage Eb of the battery country is the half-wavelength voltage [[
It is preferable that it is almost equal to EV. The resistor t341 does not necessarily have to be provided. The optical remote waveguide (a) is formed, for example, by thermally exposing Ti to the substrate (5), and the electrode (31) 02+ is formed by vapor depositing AA'.

Light from a light source (not shown) is sent through an optical fiber (41) and guided to the input optical waveguide portion (transfer) of the Matsuhatsu Enda type optical waveguide via a suitable optical coupler. Generally, intensity-modulated light outputted from the output optical waveguide section (241) is similarly guided to the optical fiber (421) via a suitable optical coupler. 43) into an electrical signal (a). This electrical signal (a) is sent to the level discrimination circuit (technique, and further pulses or t)) and is input to the counter (451) as a square wave signal cylinder.

A detection signal representing the number of rotations of the disk 001 is obtained from the counter (45).

[Relationship between Izumikyu magnet and coil]

The disk (magnet 01 when lω rotates once) is a coil (30)
Since the nearness of V changes with time, an electromotive force V is generated in the coil (to) due to electromagnetic induction. This electromotive force V
is given by the following equation.

Here, n is the number of turns of the coil, and Φ is the number of magnetic fluxes interlinking with the coil.

Figures 2 and 3 show the relationship between the size of the magnet (Ill) and the coil ■. In these figures, the magnet 01
) (hereinafter referred to as the magnet surface) and the coil C30) are both shown as circular, but the following discussion applies equally to cases where these are rectangular or other shapes.

Figure 2 (A) shows that when the diameter of the surface of magnet 01) is smaller than the diameter of the coil (to), Figure 2 CB) is larger than the diameter of the surface of magnet (1)) or the diameter of the coil field. It shows the case. FIG. 3 shows a case where the diameter of the surface of the magnet Qll and the diameter of the coil (30) are approximately equal.

Figure 4 shows the electromotive force V generated in the coil coil field and the output voltage Vc of the clip circuit when the diameter of the surface of the magnet (1) and the diameter of the coil diameter are significantly different (Figure 2). ing. When the magnet (1)) and the coil (2) approach or move away from each other, the flux linkage number Φ changes, and the number of magnetic fluxes Φ of the magnet (ttU) in the plane of the coil (2) is kept constant. Therefore, positive and negative electromotive forces V are generated in the coil (to) twice, at positions somewhat distant in time, when the two approach each other and when they move away from each other. Either one of these two electromotive forces V, for example, negative voltage, is cut (clipped) by a diode, and positive voltage level B5 or above is cut by a circuit consisting of a battery (capital) and a diode (g). . The output V of the clip circuit (marked). Only positive voltage appears in , and the peak value of this positive voltage is gb (-
” i) kept at t.

Figure 5 shows the voltage across the flux linkage circuit when the diameter of the surface of the magnet (1) and the diameter of the coil field are approximately equal (Figure 3). It shows. In this case, the magnet (1)) and the coil (support) immediately move away to the east when they approach each other, so the time for which the magnetic linkage Φ remains constant is almost zero, and the coil (301) Positive and negative electromotive force V
occur continuously over time. However, due to the action of the clip circuit 03), only the positive voltage remains, and this positive voltage is also clipped at level Eb or higher (electric voltage IE
”c).

In this way, the same voltage v0 is output from the clip circuit 2 regardless of the size of the coil turn and magnet (1), but in the following explanation (for example, Figs. 8 to 10), As shown in Fig. 3, the discussion will proceed on the assumption that the diameter of the surface of the magnet (1) and the diameter of the coil (notch) are approximately equal. It is applicable in either case.

[Relationship between applied voltage and light intensity in the light intensity modulation element]

In FIG. 1, light propagating through the input optical waveguide section unit of the Matsuhatsu Enda type optical waveguide (25) is split equally into two branching optical waveguide sections 21+@, travels through these optical waveguide section sections 21+@, and is output. The signals are combined in the optical waveguide section 241. Length I of the two branched optical waveguide sections (21) ■! 1,! ! 2 (the length from the branching point to the confluence point as shown by the broken line) is equal, the two lights propagating through the branched optical waveguide section 01) are separated from one light. Therefore, the phases match when the signals are combined between the output optical waveguide sections. Therefore, without consideration of propagation loss, the intensity of light obtained in the example output optical waveguide section is equal to that at the input optical waveguide section θ. Generally speaking, when two lights propagating through the branching optical waveguide section 21+ If there is, the same intensity as the light input from the output optical waveguide (to) to the Matsuhatsu Enda type optical waveguide (this is the maximum intensity Im)
a x) is obtained. Phase difference between two lights?2
mπ means branch optical waveguide portion (21) r22+
The length difference Δ1=1)−12 is expressed as follows.

λ0 ΔI! omII□ No. 0 (2) where n is the refractive index of the optical waveguide, and λ0 is the wavelength of light in vacuum.

If the difference Δl in the length of the branched optical waveguide portion (21) □□□ has the following relationship, these optical waveguide portions (2] 1 (
When the light propagated in 2) is combined in the output optical waveguide portion c141, the phase difference thereof becomes (2rn+1)π.

In this case, since the two lights with opposite phases are superimposed, the intensity of the light obtained in the output optical waveguide e4 becomes zero.

Now, since LiNbO3 is a crystal with an electro-optic effect, its refractive index changes when an electric field is applied. For example, in the case of LiNb03, the electrode Gll G
By applying a voltage of 2+, the refractive index of the optical waveguide portion changes as follows.

Here, Ez is the strength of the electric field in the Z direction, n8 is the extraordinary ray refractive index, and r33 is the electro-optic constant.

As is clear from equation (4), the electrode C1)l (3
When a voltage is applied between 2+, the branch optical waveguide portion c1)
On the one hand, the refractive index increases, and on the other hand, the refractive index decreases.

When the refractive index changes, the speed of light propagating through the optical waveguide (partially closed) ρ2 changes, so these lights are combined in the output optical waveguide part and the phase difference of the partials changes. For example, if the length of the branched optical waveguide portion (21) (support) satisfies equation (2), the branched optical waveguide portion O1) t22+
The phase difference when the light propagating is combined is the electrode c31)
If no voltage is applied to ■, it is 2mπ and the intensity I
Maximum light is obtained at the optical waveguide section 0a, but the electrode +3
1+ If the phase difference between these lights becomes (2m+1)π by applying a voltage to (32), the intensity of the light obtained in the optical waveguide portion Q41 becomes O. The voltage required to change the phase difference of two lights propagating through the branched optical waveguide portion (21+@) by π is called half-wavelength type [EV x.

Figure 6 shows the difference between the voltage applied between the electrodes 01) and the output optical waveguide (to) when the difference in length ΔE of the branch leading waveguide portion (21) (a) satisfies equation (2). The graph shows the relationship between the intensity of light and the intensity of light emitted. The maximum intensity Imax is obtained when the applied voltage is ±2 mVπ, and the maximum intensity Imax is obtained when the applied voltage is ±2 mVπ.
Engineering) The intensity of light becomes 0 when Vπ.

FIG. 7 shows the electrode +31) (3
2) shows the relationship between the voltage applied to the output optical waveguide (241) and the intensity of light obtained at the output optical waveguide (241).
+1) When the voltage is Vπ, light with the maximum intensity Imax is obtained, and when the applied voltage is ±2 Ill Vπ, the light intensity becomes 0.

The above-mentioned clip circuit mark) actually connects the electrode t31)■
Although the voltage applied between Q and V is limited to between Q and V, FIGS.
Light intensity curves for arbitrary positive and negative applied voltages are shown.

As can be seen from equation (1), the voltage V generated during the coil summer in Figure 1 is the number of magnetic fluxes generated by the magnet (1) (magnet α1).
strength), the number of turns n of the coil (301), and the chain (rotation speed). The flux linkage Φ and the number of turns n.

Assuming that EV is constant, the electric current [EV] changes depending on the rotational speed, and a high rotational speed generates a very high voltage.

Furthermore, the phase difference of the light propagating through the branched optical waveguide portion (21+(22)) also changes depending on the length of the optical waveguide portion to which the electric field is applied, that is, the length of the electrode 01) n.

Figures 8 and 9 show that when the disc rotates and the magnet 1+1 passes near the coil (support), the voltage generated in the coil (30j) and the voltage output from the clip circuit ■ are applied to the optical intensity modulation element. The intensity of light obtained from the output optical waveguide t24 of the light intensity modulation element when applied between the electrodes C(1) (321) is shown with respect to the time axis. C) and FIGS. 9(A) to (C) are
Voltage generated in coil (to)) or electrode (31) □□□
For reference, the effect when the voltage is applied directly between the two is shown for reference, and Fig. 8 υ) (g) and Fig. 9 υ) (g) show the output type EV of the clip circuit (g). is the electrode (31) (3
This is an example of the present invention in which the voltage was applied between 21 and 21. In addition, FIG. 8 shows that when the voltage applied between the electrodes [31] (321 is 0, two branched optical waveguide portion molecules 21) t
22) The phase difference when the light propagating through is combined is 2mπ
□ (corresponding to Equation (2) and Figure 6), Figure 9 shows a configuration where the phase difference between the two lights is (2m+1)π when the voltage applied to the electrode (31) is 0. This is the case (corresponding to equation (3) and FIG. 7). Since the waveform in FIG. 8 is the same as the waveform in FIG. 9 inverted between the light intensity O and Imax, only FIG. 9 will be described.

As described above, when the magnet (1)) passes near the coil (30), positive and negative voltages are subsequently generated in the coil (30), and the absolute values of these voltages are equal. Also, the seventh
As shown in the figure, the light intensity is symmetrical with respect to positive and negative voltages with the applied voltage at the center being 0, and the applied voltage is V or ±V.
When π, the light intensity shows the maximum value. Once, the coil (
30) When the absolute value of the generated voltage V is less than Vπ, two peaks slightly shifted on the time axis appear in the light intensity, and these peak values do not reach the maximum intensity Imax (the Figure 9 (5), solid line). Then, when the absolute value of the voltage ■ is Vπ, the peak value of the light intensity becomes the maximum intensity Imax (FIG. 9(A), broken line).

The generation type of the coil circle [(When the absolute value of V exceeds V, r,
A dent occurs in the peak part of the light intensity waveform (Fig. 9 (B)
)). This is electrode f31) Applied voltage force 1 to f321
This is because when the absolute value Vπ of '2 is exceeded, the light intensity becomes smaller than Imax (see FIG. 7).

When the absolute value of the voltage ■ becomes 2V, the above-mentioned dent has a strength of O
As the light intensity decreases, the light intensity waveform substantially has four peaks (FIG. 9(C)).

It is easy to understand that as the absolute value of the voltage V becomes higher, more pulse-like waveforms occur in the light intensity.

■The negative voltage of the clip circuit is cut off when the coil is induced in the summer. Therefore, only a positive voltage of the voltage (2) causes a change in the light intensity of the output light.

If the absolute value of V is less than ■, a light intensity waveform similar to that shown in FIG. 9(A) can be obtained (however, there is one peak) (in FIG. 9)).

When the absolute value of voltage ■ exceeds v4, a clip circuit [with]
Since the voltage higher than V, (=Eb) is clipped by , the output voltage vc in the clip circuit is
held constant. Therefore, the light intensity of the output light is also Im
ax is held constant and becomes one pulse-like waveform (
Figure 9(g)).

[Function of the rotation speed detection device]

FIG. 10 shows the output signal (a) of the photoelectric conversion element (43),
(B) shows the output signal (b) of the DAQ1 and the level discrimination circuit. (A) shows the disc (A) when the rotation speed of the disc (1α is small). If is large, the same figure (
C) is a case where the rotation speed is even higher. These figures are all under the condition that the difference in length of the branched optical waveguide portion tan (221) of the Matsuhatsu Enda type optical waveguide (25) satisfies equation (3) (Figs. 7 and 9). ).

The waveform of the output signal (a) of the photoelectric conversion element (431) is the waveform of the output signal (a) of the photoelectric conversion element (431).
is the same as the intensity of light obtained in As is well known, the signal waveform may be inverted depending on the configuration of the element (43). As mentioned above, the magnetic flux generated by the magnet (1) and the number of turns of the coil (%n). If constant, the coil ■
The voltage generated at the disc (10) depends on the number of rotations of the disk (10), and the higher the number of rotations, the higher the voltage. Figure 10 (A) corresponds to the case where the absolute value of the generated voltage V is lower than V, Figure 10 (B) corresponds to the case where it is approximately equal to V, and Figure 10 (C) corresponds to the case where it is approximately equal to 2vπ. (See Figure 9, Q) (g)).

As can be seen by comparing Figures 10 (A) to (C), regardless of the rotational speed of the disk 00), the signal (a) is a disk! ][One pulse always appears for one revolution of Il. This pulse-like component of the signal (a) is level-discriminated by a threshold value (S) set in a level discrimination circuit (44) and waveform-shaped (signal (b)).

The counter (45) measures the interval between pulses (pulse interval (P t )) included in the signal (b), or represents a constant temporal velocity or angular velocity.

As mentioned above, the negative voltage of the positive and negative generated voltages of the coil +301 or the diode (3) of the clip circuit (G)
1il, and the positive voltage level Eb (2■
, ) Above is the output type BE V e of the battery (9) and the diode (because it is cut by 5, it is a clip circuit)
One pulse-like component appears for one rotation of the disk +10), and as a result, one pulse component appears for one rotation of the disk 0■ in the output signal (a) of the photoelectric conversion circuit (43). Components such as these are now appearing.

If the clip circuit c13) does not exist and the voltage V generated by the coil field is applied directly between the electrodes l31), as can be seen from FIGS. 9(B) and (C), the disc (
10) Two or more pulse-like components appear in the signal (a) during one rotation. Moreover, the number of pulse-like components is a disk (l
It increases as the rotational speed of O) increases. Therefore, the waveform processing of signal (a) has to become complicated. For example, in order to obtain one pulse per rotation of the disk QOI, it is necessary to provide a low-pass filter at the next stage of the photoelectric conversion element (43), and the pass band of this filter is a low frequency band. must be set. If this pass band is made too low, if the disk (10) rotates at high speed and the frequency of this high speed rotation (rotation speed of 7 seconds) exceeds the frequency of the pass band set low, measurement will become impossible. In this invention, since only one peak appears per rotation in the signal (a), there is no need to provide a filter as described above, and it is possible to widen the rotation speed detection range.

[Modified example]

Figure 1) shows a modification of this invention.

Zener diode (38
) is connected. Zener breakdown voltage V2 of this Zener diode (support). is preferably about the cow wavelength voltage Vπ.

Another example of a clip circuit is a circuit that clips the parts of a coil that exceed a certain level (±V□) of positive and negative voltages that sometimes occur. , signal (a) has disk +I
Although a maximum of two p pulse components appear per one revolution of QI, the signal processing thereof is simpler than when four or more pulse components appear.

In the above embodiment, one permanent magnet α is provided on the disk 00), but if a plurality of permanent magnets are provided at equal angular intervals, the accuracy of rotational speed and angular velocity detection will be improved. In addition, when detecting a specific angular position of the disk (10), it is necessary to arrange the plurality of permanent magnets at equal angular intervals, and the detection signal (for example, the output signal (b) of the level discrimination circuit (44)) Let us assume a specific arrangement state as it appears in .

The substrate (20) may be any material as long as it has an electro-optical effect in which its refractive index changes upon application of an electric field. Therefore, the optical waveguide can also be fabricated using various techniques and materials depending on the type of substrate other than Tl thermal diffusion. Since the electrode 0]1 f32) changes the refractive index of the optical waveguide portion by applying a voltage, it can take various shapes and arrangements depending on the properties of the substrate. For example, electrode C3
1) (32) may be arranged to sandwich one branched optical waveguide portion. It is also possible to ground one of the electrodes. The electrode is AI! For example, it can be realized using other materials such as Ti.

Elements that modulate light intensity by applying an electric field include, in addition to those using the above-mentioned Matsuhatsu Enda type optical waveguide, devices that use, for example, a directional coupler between optical waveguides, and Japanese Patent Application No. 57-86'. No. 178 (Unexamined Japanese Patent Publication No. 58-20
For example, a waveguide type optical beam splitter disclosed in Japanese Patent Publication No. 2406 may be used.

This invention includes only physical quantities related to the rotation of a rotating body.
It can also be applied to the measurement of physical quantities related to the movement of an object that periodically reciprocates on a fixed two-dimensional or three-dimensional path. In addition, if two permanent magnets are installed on one object that moves relatively, the periodic reciprocating movement of this object can be determined by measuring the time interval during which these two magnets pass near the coil. You can measure the speed of an object without it.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing an example of a rotation speed detection device, Figures 2 and 3 are diagrams showing the size and shape of the permanent magnet and coil, and Figures 4 and 5 are diagrams showing the size and shape of the permanent magnet and the coil. These are graphs showing the number of magnetic fluxes, their changes, the electromotive force generated in the coil, and the output voltage of the clip circuit. Figure 4 shows the output generated by the permanent magnet and coil shown in Figure 2, and Figure 5 shows the output produced by Figure 3. This is a graph showing the relationship between the light intensity and the light intensity. Figure 6 shows the structure set so that the light intensity is maximum when no voltage is applied, and Figure 7 shows the relationship between the light intensity and the light intensity when no voltage is applied. Figures 8 and 9 show that the optical intensity of the output light obtained from the Matsuhatsu Enda type optical waveguide when the permanent magnet passes near the coil is determined by the electromotive force of the coil. These are waveform diagrams showing the waveforms for various applied voltages, divided into cases where the voltage is directly applied to the electrode and cases where the output voltage of the clip circuit is applied to the electrode. Fig. 9 shows the structure set so that the light intensity becomes zero when no voltage is applied, and Fig. 10 shows the structure set so that the light intensity becomes the maximum when no voltage is applied. These are diagrams showing the output signal waveforms of the circuit, in which (A) shows the waveform when the rotational speed is relatively small, (B) shows the waveform when the rotational speed is intermediate, and (C) shows the waveform of the output signal of the circuit.
1) shows cases where the number of rotations is relatively large, and Figure 1) shows (10+-...disk, (1))...permanent magnet, (20)e...electro-optic crystal substrate (light intensity modulation). element)
, C1) @...branched optical waveguide part of Matsuha Tsuenda type optical waveguide, flaw)...Matsuhatsu Enda type optical waveguide, measurement.
・Coil, G1) (321-・-electrode, (33) ・
・* 'y IJ tube circuit, +431-- Photoelectric conversion element, +44)--Level discrimination circuit, +451--
·counter. that's all

Claims (3)

[Claims] (1) A magnetic flux generating section provided on one side of a relatively moving object, an element provided on the other object that generates an electromotive force when the magnetic flux generating section passes relatively close to it, and an electromotive force generation A clip circuit is connected between both terminals of the element, the output voltage of the clip circuit is applied, the element modulates the light intensity by applying this voltage, and information about the movement of the moving object is obtained from the change in the modulated light intensity. A device for detecting rotational speed, speed, etc., comprising means for creating. (2) The clip circuit causes the positive voltage generated in the electromotive force generating element to
A detection device for detecting rotational speed, speed, etc. according to claim (1), which clips a negative voltage above a predetermined positive level and below a predetermined negative level. (3) The clip circuit causes the positive voltage generated in the electromotive force generating element to
The device for detecting rotational speed, speed, etc. according to claim (1), which clips one of the negative voltages and clips the other portion exceeding a predetermined level.