JPS6125069A - Detector for speed, angular velocity and the like - Google Patents

Abstract

PURPOSE:To enable a highly reliable measurement and a low-loss long range transmission without deviation in the optical axis, by arranging a magnetic flux generator section provided on a rotor, an element for generating an electromotive force and a Mach-Zehnder type lightwave guide. CONSTITUTION:A permanent magnet 11 is fixed on a rotor 10 and a coil 30 is provided which generates an electromotive force as the magnet 11 passes near it. Light from a light source is introduced into inputted lightwave guide portions 21c-24c of four mach-Zehnder type lightwave guides 21-24 through an optical fiber 80 and Y-shaped type lightwave guides 25, 26 and 27. Pairs of electrodes 41a, 41b-44a, 44b (witht the lengths L, L/2, L/4 and L/8) are formed on a substrate 20 in the lightwave guide portions 21c-24c. Then, the electromotive force induced in the coil 30 is applied between the electrodes. Then, light modulated in the intensity with the lightwave guides 21-24 is converted 51-54 to electricity through optical fibers 81-84 and inptted into a CPU91 through a level discrimination circuits 61-64 (U, L), counters 71-74 (U, L) and an interface 90.

Description

Detailed Description of the Invention Background of the Invention [Technical Field of the Invention] The present invention uses optical signals to detect the rotational angular velocity of a rotating body, the velocity of an object periodically moving on a fixed path, the velocity of other objects, etc. The present invention relates to a detection device using

[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. When the data to be optically transmitted is some kind of measurement data, such as rotational angular velocity, it is preferable to perform the measurement or detection in the form of light and to optically transmit the measurement data as it is through an optical fiber. Here,
There is value in using what are called optical sensors and optical fiber sensors. Combining optical sensor detection and optical fiber transmission enables highly reliable measurement and long-distance transmission 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 angular velocity, etc., multiple holes are drilled around the opaque rotating plate, and these holes are placed at positions sandwiching the opaque rotating plate from both sides on the circular motion locus. There is one that has a pair of optical fibers facing each other.

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. Therefore, an on/off optical signal corresponding to the rotational angular velocity 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, which reduces the intensity of the resulting photodetection signal. 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 more complicated, and strict alignment of the optical axes 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 speed, angular velocity, etc. detection device that 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 speed, angular velocity, etc. detecting device 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, so that the magnetic flux generating part is fixed to the relatively moving body, such as a rotating body. An element that generates an electromotive force by passing near it, such as a coil, and multiple elements that modulate the intensity of multiple lights guided from a light source to different degrees when the generated electromotive force is applied. , and means for creating information regarding the speed of a moving object, such as rotational angular velocity, speed data, etc., from changes in light intensity of a plurality of modulated lights.

Every time the magnetic flux generator passes near the electromotive force generating element,
The intensity of the plurality of lights directed from the light source is modulated to different degrees, eg, the intensity is increased or decreased. The intensity modulation pattern between the plurality of intensity-modulated lights changes depending on the passing speed of the magnetic flux generating section. Therefore, by analyzing this intensity modulation pattern, velocity and angular velocity data of a moving object can be obtained.

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

Some conventional magnetic rotation angular velocity sensors include a rotary plate around which a permanent magnet is fixed, or a rotary plate whose periphery is magnetized. This rotational angular velocity sensor extracts an electrical signal representing the rotational angular velocity using a magneto-electric conversion element that responds to the magnetism of a rotating plate. According to the present invention, the rotary plate of such a conventional magnetic rotation angular velocity sensor can be used as is and easily modified into an optical measurement and transmission system using an optical fiber.

DESCRIPTION OF EMBODIMENTS [Configuration of rotation angular velocity detection device] In FIG. 1, a disk (10) is positioned at the center of the shaft for which rotation angular velocity is to be detected, for example, the output shaft of a motor or a shaft connected thereto (as shown in the diagram). It is fixed, and the disk scream rotates together with this axis. Around this disk (10) there are 1
Two permanent magnets (11) are embedded. Disc (10)
At an arbitrary point in the locus of the magnet (■1) that moves circularly with the rotation of the magnet (1t
Coil +30 so as to face the coil shown in a) near it.
1 is placed and fixed in that position by a suitable fixing member.

The magnet (11) can also be provided on the circular surface of the disk (10). Also in this case, the coil (301 is connected to this magnet (1
1) It is fixed in such a way that it interlinks as much as possible with the magnetic flux generated from 1). Instead of providing the permanent magnet (11) in the disk (10), the disk (10) itself is made of a ferromagnetic material, or a ferromagnetic ring is fitted around the disk (10), and the ferromagnetic material is magnetized. You can do it like this.

The light intensity modulation element is made of a crystal having an electro-optic effect, for example, a LiNbO3 crystal substrate C crystal substrate C acidified Matsuhatsu Enda type optical waveguide (21+ (22123+ and factor)
Contains. The Matsuha Tsuenda type optical waveguide (21) is
Input optical waveguide part (21C), this optical waveguide part (21C)
Two branched optical waveguide parts (21a) (21b) branched from 1C) at equal angles and these optical waveguide parts (
21a) (21b) join the output optical waveguide part (2
1d).

Other Matsuhatsu Enda type optical waveguides (22)~c! The slope has exactly the same structure. In FIG. 1, subscripts (a) to (d) are added to symbols (2) to (24) to indicate the input optical waveguide section, the two branching optical waveguide sections, and the output optical waveguide section. It is expressed as

These four Matsuhatsu Enda type optical waveguides 21i~(24
In order to supply light from one optical fiber (80) to +, three figure-7 optical waveguides (25+
(26) and (capital) are formed. Light from a light source (not shown) is sent through an optical fiber (801) and guided to a figure-7 optical waveguide (25) via a suitable optical coupler.
And the waves are divided equally. The two demultiplexed lights are split into two beams of equal intensity in the 7-shaped optical waveguides (C) and (A), respectively, and are then passed through the input optical guides of the four Matsuhatsu Enda type optical waveguides (2) 1 to (24+). Wave path part (210
) to (24e). In this way, light of equal intensity will be input into the optical waveguide (2+1~ example).

As an optical demultiplexer, such a Y-shaped optical waveguide (25) ~
It is also possible to use something other than (5), or to guide the four lights to the optical waveguides (21) to (24+) using four optical fibers. It is sufficient that light having an intensity equal to (21) to factor) is input. However, the level discrimination circuit (61
U) If the discrimination levels of (6xL) to (64U) (64L) are adjusted appropriately, light of equal intensity does not necessarily have to be input to the optical waveguides (21) to t241.

Branch optical waveguide part of Matsuha Tsuenda type optical waveguide 011 (
A pair of electrodes (41a) (41b) are formed on the substrate aO+ so that a part of them overlaps 21a) (21b), respectively. Pairs of electrodes are also provided on the branched optical waveguide portions of the other Matsuhatsu Enda type optical waveguides (branches) to (24), respectively. These electrodes are (4211
) (42b), (43B) (43b) and (44a
) (44b). Electrodes (4xa) and (41
t+) have the same length, and let this length be L. The lengths of other electrodes (42a) and (42b) are set to L/2, the lengths of (43a) and (43b) are set to L/4, and the lengths of (44a) and (44b) are set to L/8. has been done.

Both ends of the coil (30) are connected to these electrodes (21a) (2
1b), and the voltage induced in the coil (301) is applied between these electrodes (21a) (2111).Similarly, the voltage between both ends of the coil field is applied to the electrodes (42a) (4211). ), (43a) (431+
) and between (44a) and (44b), respectively.

Y-shaped optical waveguide (25t~(a) and Matsuhatsuenda type optical waveguide II)~C! The gradient is formed, for example, by thermally diffusing Ti into the substrate 10), and the electrode (41a)
~(44b) is made by depositing A/.

As will be described later, the light intensity-modulated by the Matsuhatsu Enda type optical waveguides (21) to 4 is guided to the optical fibers (81) to (84) through appropriate optical couplers, respectively. ) is the photoelectric conversion element 61)
~(541 converts each into an electrical signal.

The output signal of the photoelectric conversion element (51) is sent to two level discrimination circuits (61U) (61L). Discrimination levels SU and SL are set in these level discrimination circuits (61U) (61L), respectively. The signals converted into pulse or square waves by being discriminated at such a discrimination level are sent to counters (71U) (71L).
) and counted. Other photoelectric conversion elements (521,
Similarly, the output signals of +53) and (54) are also output from two level discrimination circuits (62U), (62L) and (6
3U) (63L), (64U) (64L), and further counters (72U) (72L),
(73U) (73L) (74U) Input to (74L). The count values of these counters (71U) to (74L) are determined by one revolution of the disk (10) and the interface (
90) to the CPU (91). The counters (71U) to (74L) are reset every rotation of the disk (lα (at times other than the time period T when the magnet (11) is passing near the coil field).This reset signal is, for example, It can be obtained from another coil (the path shown) which generates an electromotive force by passing the magnet (11).It is preferable to synchronize the resetting of the counter and the reading of the count value of the counter.

[Relationship between permanent magnet and coil]

When the disk (10) rotates once, the magnet (11) turns into a coil 00.
) passes once. At this time, the magnetic flux generated from the magnet (11) interlinks with the coil (30), and the number (density) of the interlinked magnetic flux changes with time, so the electromotive force in the coil (30) is due to electromagnetic induction. occurs. 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.

The relationship between the sizes of the magnet (11) and the coil (30) is shown in FIGS. 2 and 3. In these figures, both the surface of the magnet (11) facing the coil (30) (hereinafter referred to as the magnet surface) and the coil (30) are shown as circular, but if these are rectangular or other shapes, The following discussion equally applies.

In Figure 2 (A), the diameter of the surface of the magnet (11) is the same as that of the coil (30).
2) indicates a case where the diameter of the surface of the magnet (11) is larger than the diameter of the coil group. FIG. 3 shows a case where the diameter of the surface of the magnet (11) and the diameter of the coil (30) are approximately equal.

FIG. 4 shows the electromotive force V generated in the coil (30) when the diameter of the surface of the magnet (11) and the diameter of the coil (30) are significantly different (FIG. 2).

The number of flux linkages Φ changes when the magnet (11) and the coil (30) approach and move away from each other, and while the magnet (11) is included in the plane of the coil (30) (Fig. A)) and the coil (30) are included in the plane of the magnet (11) (FIG. 2(B)), the flux linkage number Φ is kept approximately constant. Therefore, positive and negative electromotive forces V are generated in the coil (3o) twice, at positions somewhat separated in time, when they approach each other and when they move away from each other.

FIG. 5 shows the magnetic flux linkage when the diameter of the surface of the magnet (11) and the diameter of the coil mark (see FIG. 3) are approximately equal. In this case, since the magnet +Ill and the coil (30) immediately separate when they approach, the time during which the flux linkage number Φ is constant is almost zero, and the coil (30) has positive and negative The electromotive force V is generated continuously over time.

In the following explanation, as shown in FIG.
The discussion will proceed on the assumption that the diameter of the surface of and the diameter of the coil (to) are approximately equal. This is because this is the second
This is because the explanation is easier than in the case of the relationship between the magnet (11) and the coil (support) as shown in the figure. However, the present invention is applicable to either the case of FIG. 2 or FIG. 3.

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

In Figure 1, four Matsuhatsu Enda type optical waveguides t2
Nos. 11 to 11 differ only in the length of the electrode pair and have the same other configurations, so the Matsuhatsu Enda type optical waveguide Gl+ will be described as a representative of these optical waveguides.

The light propagating through the input optical waveguide section (210) of the Matsuhatsu Enda type optical waveguide (21) is transmitted through the two branch optical waveguide sections (
21a) (211+), propagates through these optical waveguide sections (21a) and (21b), and is combined in the output optical waveguide section (21d). When the lengths 11.12 (lengths from the branch point to the confluence point as shown by the broken line) of the two branched optical waveguide parts (21a) (21b) are equal, the branched optical waveguide parts (21a) (211> ) are branched from one light, and therefore have the same phase when combined in the output optical waveguide portion (21d).

Therefore, if propagation loss is not considered, the intensity of the light obtained at the output optical waveguide section (21d) is equal to that at the cutting optical waveguide section (210).

Generally speaking, the branch optical waveguide portion (21a) (211
)) The two lights that have propagated through the output optical waveguide section (2
1d), if their phase difference is 2mπ (m is 0 or an integer), the output optical waveguide (21d) will have the same intensity as the light input to the Matsuno λ Zuender type optical waveguide (21). (This is called maximum intensity Imax) light can be obtained. The phase difference between the two lights is 2mπ, which means that the difference in length between the branching optical waveguide portions (21a) and (21b) is Δ1=l
When expressed as l-22, it is expressed as follows.

λ Δ/=m (2) where n is the refractive index of the optical waveguide and λ. is the wavelength of light in a vacuum.

Difference in length Δl between the branched optical waveguide portions (21a) and (21b)
has the following relationship, these optical waveguide parts (2
], a) When the light propagating through (2111) is combined in the output optical waveguide section (21d), the phase difference becomes (
2m+1)π.

In this case, since two lights of opposite phases are superimposed, the light intensity obtained in the output optical waveguide (21d) becomes O.

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 Z-cut L i N b O3, the electrode (
By applying a voltage to 41a) (41b), the refractive index of the optical waveguide portion (21a) (2111) changes as follows.

Here, E2 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 electrodes (41a) (4
111), when a voltage is applied between the branch optical waveguide portion (
21a) The refractive index of (21b) increases on the one hand and decreases on the other hand. When the refractive index changes, the speed of light propagating through the optical waveguide portions (21a) (211, 1) changes, so the phase difference when these lights are combined in the output optical waveguide portion (21d) changes. Change.

For example, if the lengths of the branched optical waveguide sections (21a) and (21b) satisfy equation (2), the phase difference when the lights propagating through the branched optical waveguide sections (21a) and (2111) are combined. If no voltage is applied to the electrodes (41a) (41b), the light is 2mπ and the intensity Irr+ax is obtained in the optical waveguide portion (21d);
) (41b), if the phase difference between these lights becomes (2m+1)π, the intensity of the light obtained at the optical waveguide portion (21d) becomes 0. The voltage required to change the phase difference of two lights propagating through the branched optical waveguide portions (21a) (2113) by π is called a half-wavelength voltage V.

Figure 6 shows the branched optical waveguide section (21a) (211))
shows the relationship between the voltage applied between the electrodes (41a) (4, 1b) and the intensity of light obtained in the output optical waveguide (21d) when the difference in length Δl satisfies equation (2). There is. Maximum intensity I max when applied voltage is ±2mV
A light of 200 m is obtained, and the applied voltage is ±(2m+1)■.

When , the intensity of light becomes 0.

FIG. 7 shows the electrode (
41a) shows the relationship between the voltage applied between (411+) and the intensity of light obtained in the output optical waveguide (21d). The applied voltage is ±(2m+1)V□. sometimes maximum intensity I
When maximum light is obtained and the applied voltage is ±2 mV, the light intensity becomes O.

The voltage ■ generated in the coil (30) in Figure 1 is the voltage (1)
As can be seen from the equation, it changes depending on the number of magnetic fluxes generated by the magnet (11) (strength of the magnet (11)), the number of turns of the coil (30), and the copper sheath. The number of flux linkages Φ and the number of turns n.

If V is constant, the voltage V changes depending on the rotational angular velocity,
The higher the rotational angular velocity, the higher the voltage generated.

Figures 8 and 9 show the disk (1) in the configuration of Figure 1.
0) rotates and the magnet (11) passes near the coil (30), the intensity of light obtained in the output optical waveguide portion (21d) is shown on the time axis. FIG. 8 shows two branched optical waveguide sections (21a) (21+) when the voltage applied between the electrodes (4, 1a) (4, 1b) is 0.
), the phase difference when the light propagating through is combined is 2 mπ (corresponding to Equation (2) and Figure 6), and Figure 9 shows the configuration in which rEO is applied between the electrodes (41a) and (4113). When the phase difference between the two lights is (2m+1)π (
(corresponding to equation (3) and FIG. 7). Since the waveform of FIG. 8 is the same as the waveform of FIG. 9 inverted between light intensity 0 and I max, only FIG. 9 will be described.

- As mentioned above, when the magnet (11) passes near the coil (30), positive and negative voltages are successively generated in the coil (30), and the absolute values of these voltages are equal. Furthermore, as shown in Fig. 7, the light intensity is symmetrical with respect to positive and negative voltages with EO as the center, and the light intensity reaches its maximum value when the applied voltage V is ±V. . Therefore, when the absolute value of the peak value of the voltage V generated by the coil (rabbit) is less than v3, two peaks appear in the light intensity that are slightly shifted on the time axis, and this peak value is the maximum intensity Imax
(Fig. 9(A), solid line). And electric EE
When the absolute value of the peak value of V is v4, the peak value of the light intensity becomes the maximum intensity I max (Figure 9 (N, broken line)
.

Coil 00) generation type [absolute value of peak value of EV is ■,
If the value exceeds 1, a dent occurs in the peak portion of the light intensity waveform (FIG. 9(B)). This means that when the absolute value of the EEV applied to the electrodes (41a) (41b) exceeds V□, the light intensity Im
This is because it is smaller than ax (see FIG. 7).

When the absolute value of the peak value of the voltage V becomes 2V, the above-mentioned depression decreases to the intensity O, so that the light intensity waveform substantially has four peaks (FIG. 9(C)).

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

In other words, the absolute value of the peak value of electric current (EV) is 3V.

When this happens, six peaks appear in the light intensity waveform.

When the absolute value of the peak value of EV becomes 4V, eight peaks occur in the light intensity waveform (Fig. 9(D)).

When the absolute value of the peak value of the voltage (2) reaches 8V, 16 peaks occur in the light intensity waveform (FIG. 9 (g)).

Since the lengths of the electrodes of the Matsuhatsu Enda type optical waveguides c21) to (24) are different, even if the applied voltages are the same, the degree of light intensity modulation in the output light is different.

” - electrodes (4ta) (41b), (42a) as mentioned
(42b), (43a) (43b), (44a)
(4413) The rD length ratio is set to 824:2:1.

Assuming that the half-wave voltage of the Matsuhatsu Ender leading waveguide (21) having the electrodes (41a) (4, 1b) with the longest length L is ▪ as described above, then the other Matsuhatsu Ender leading waveguide c2
The half-wave voltages at 2), +231, and (24) are 2 V, 4 V, and 8 V, respectively.

Therefore, these Matsuhatsu Enda type optical waveguides (2)
) to 041 output optical waveguide portions (21d) to (24d
) The intensity waveform of the light output from each is also different. For example, when the peak value of the voltage generated by the coil (30) is 8 V, the output optical waveguide portion (21d)
As mentioned above, 16 peaks occur in the optical intensity waveform of the optical signal output from the output optical waveguide (
22d) Only 8.4 and 2 peaks appear in the light intensity waveforms of the lights in (23d) and (24d), respectively.

[Function and effect of rotational angular velocity detection device] Fig. 10 shows
Output signals of photoelectric conversion elements (51) to (54).

The output signals of the level discrimination circuits (61U) (64U) and the output signals of the level discrimination circuits (61L) to (64L) are shown. The figure (A) shows the case when the rotation speed of the disc (10) is small, the figure (B) shows the case when the rotation speed is higher than the figure (A), and the figure (C) shows the case when the rotation speed is even higher. .

Both of these figures show the Matsuha Tsuenda type leading waveguide 01.
) to 圀) under the condition that the difference in length of the branched optical waveguide portions satisfies equation (3) (corresponding to FIGS. 7 and 9).

The waveforms of the output signals of the photoelectric conversion elements (51) to (54) are as follows:
This has the same shape as the intensity of the light obtained in the output leading waveguide portions of the Matsuhatsu Enda type leading waveguides (21) to (24j).(As is known, the signal waveform may be reversed depending on the configuration of the photoelectric conversion element. - As mentioned above, there is a magnet (
If the magnetic flux generated in 11) and the number of turns no of the coil (30) are constant, the voltage generated in the coil (30) is
10) It depends on the number of rotations, and the higher the number of rotations, the higher the voltage. In Fig. 10 (A), when the absolute value of the peak value of the generated voltage (■) is equal to , ω) in the figure is 2 V, and when it is approximately equal to , C) in the figure is 4 V.

(See Figure 9).

As can be seen by comparing the output signal waveforms of the photoelectric conversion elements in the signals of FIGS. 10 (A) to (C), as the rotation speed of the disk (10) increases, the magnet (11)
As the time T for passing through the vicinity of , becomes shorter, the number of pulse-like components generated in one pass increases. Therefore, as the rotation speed increases, the output signal of the photoelectric conversion element contains more high-order harmonic components.

Moreover, as mentioned above, the Matsuhatsu Enda type optical waveguide c21
) to (24), the electrode length ratio is 8:4:2:1
Therefore, the pulse-like components (the peak value is the maximum intensity Ima) appearing in the output signals of the photoelectric conversion elements (51) to (54)
the pulse-like component that has reached the value V S max corresponding to x)
The ratio of numbers also agrees with this ratio.

On the one hand, the output signals of the photoelectric conversion elements (51) to (54) are transmitted to level discrimination circuits (61U) to (64U), respectively.
) and is converted into a pulse or square wave signal. In this embodiment, the upper discrimination level SU is set to a value very close to the peak value V S max of the output signal of the photoelectric conversion element, for example, 7 V S max / 8 or more.

On the other hand, the output signals of the photoelectric conversion elements (51) to (54) are transmitted to level discrimination circuits (61L) to (64L), respectively.
), and is similarly converted into a pulse or square wave signal.

The lower discrimination level SL is a value very close to O, for example V
S max is set to 78 or less.

The output pulse signals of the level discrimination circuits (61U) to (64U) are then counted by counters (71U) to (74U). The output pulse signals of the level discrimination circuits (61L) to (64L) are counted by counters (71L) to (74L). Since the output signals of the level discrimination circuits have different pulse widths, they may be converted into pulse signals of a constant width using, for example, a monostatic multivibrator and then input to the counter.

The count values of counters (71U) to (74L) are disks (10
) is taken into the CPU (91) every rotation and stored in its memory.

Figure 11 shows the intensity of light output from the Matsuhatsu Enda type leading waveguide at the time when the voltage generated by the coil (30) reaches its peak value, with the generated voltage on the horizontal axis and the light intensity on the vertical axis. be. The light intensity curve is shown using the electrode length as a parameter for convenience. That is, L is the output light intensity of the Matsuhatsu Enda type optical waveguide (21), L/2,
L/4 and L/8 are optical waveguides (22) and Q3), respectively.
The output light intensity is 24+. - As mentioned above, the output signal curves of the photoelectric conversion elements (51) to (54) also have the same shape as this light intensity curve.

FIG. 11 also shows the counted values of the counters (71U) to (74L) in correspondence with the voltage between the coil terminals. The counters (7tU) and (71L) form a pair, and a pair of these count values represents one piece of information. Similarly, counters (72U) and (72L), (73U) and (73L),
(74U) and (74-L) each form a pair, and the count values of the paired counters each represent one piece of information.

The CPU (91) has a pair of counters with a count value of 2.
．． 6.10.14.18.22.26.30,...fist...
, and if the count value of the counter with the upper discrimination level SU is equal to or larger than the above count value (generally larger by 2), then the information represented by the count value of the paired counter is set to binary 1. , and in other cases, the binary number O is used. Among the pairs of count values of the counter shown in FIG. 11, the pair of count values surrounded by an ellipse is determined to be a binary number 1.

FIG. 11 further shows the binary values determined in this way. The binary value of the electrode length is the first digit, and the binary values of the electrode lengths L/2, L/4, and L/8 are the second digit.
As 3 and 4 digits, a 4-digit binary number is created. It can be seen that these four-digit binary numbers represent the voltage generated across the coil. For example, when the generated voltage is v, the binary number is 0001.2 V, (0010.4 V when D), 0100, and 1000 when Bv.

As mentioned above, since the coil generated voltage (2) is proportional to the rotational angular velocity of the disc (10), the above four-digit binary number represents the rotational angular velocity of the disc (10).

In this way, it can be seen that the rotational angular velocity of the disk (10) can be expressed as a coil-generated voltage and detected as a digital quantity with an accuracy of v.

[Other Examples]

FIG. 12 shows another embodiment. In this figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and their explanation will be omitted.

A diode (111) as a rectifying element is connected between both ends of the coil (30) via a resistor (115). As mentioned above, positive and negative voltages are generated in the coil 00), but one of them is cut off by the diode (111). Therefore, the number of pulse-like components in the light intensity waveform of the output light of the Matsuhatsu Enda type optical waveguides 01) to (24+) is half that of the above embodiment.

Signal processing circuits (101) to (104,) are connected to the output sides of the photoelectric conversion elements (51) to (54). Since these signal processing circuits have exactly the same configuration, the circuit (1
01) will be explained.

The configuration of the signal processing circuit (101) is shown in FIG. Since the number of pulse components appearing in the intensity waveform of the output light of the Matsuhatsu Enda type optical waveguide (21) is half that of the embodiment shown in FIG. 1, the count values of the counters (71U) (71L) are also half. In FIG. 11, the counter (71L)
Of the count values, the values surrounded by an ellipse are 2.6.10.14.
The half value of 18.22.26.30... is 1.3.5
．． 7.9.11.13.151111. These are all odd values. A binary counter (106) counts the number of output pulses from the level discrimination circuit (61L) and generates an H level output when the counted value is an odd number. 2
The output of the advance counter (106) is sent to the gate circuit (108). The comparison circuit (107) is a counter (71U)
and (71L) are compared, and if the count value of the counter (71U) is equal to or greater than the count value of the counter (71L), a signal to open the gate of the gate circuit (108) is output.

Therefore, from the gate circuit (108), the counter (
When the pair of count values 71U) and (71L) is half the value surrounded by an ellipse in FIG. 11, an H level signal is output. This H level signal corresponds to the binary number 1 mentioned above. The output signals of the signal processing circuits (101) to (104) (output signals of the gate circuit (108), etc.) are transferred to the magnet (11).
) is temporarily stored after passing near coil 00). The output signal of the latch circuit (105) is
It can be easily understood that it represents the four-digit binary number shown in FIG.

This embodiment has the advantage that a signal representing the angular velocity of the disk portion in digital quantity can be obtained by the hardware circuit without requiring processing by the CPU (91).

[Modified example]

In the above embodiment, one permanent magnet (11
), but a plurality of permanent magnets may be provided at equal angular intervals. In FIG. 14, eight permanent magnets (11) of equal strength are provided around a disk (10) at equal angular intervals. In this figure, eight Matsuhatsu Enda type optical waveguides are provided, and the lengths of the electrodes provided in each optical waveguide are L, L/2, L/4, L/
8, L/16, L/32, L/64, L/128.

A plurality of coils (same as the number of Matsuhatsu Enda optical waveguides) may be provided to be connected to the electrodes of each Matsuhatsu Enda optical waveguide, and the same number of permanent magnets may be provided in the disk (10) corresponding to these coils. . In this case,
In addition to varying the electrode length, the number of turns of the coil and the strength of the permanent magnet may also be varied.

The substrate CO) 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 thermal diffusion of Ti. Since the electrode 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, the electrodes may be arranged to sandwich one branched optical waveguide portion of the Matsuhatsu Enda type optical waveguide. It is also possible to ground one of the electrodes. The electrodes can be made of a material other than Al, such as Ti.

As an element that modulates the light intensity by applying an electric field, in addition to the above-mentioned Matsuhatsu Enda type optical waveguide, for example, a device using a directional coupler between optical waveguides, Japanese Patent Application No. 57-86178 (Unexamined Japanese Patent Publication No. 58-202
For example, a method using a waveguide optical beam splitter disclosed in Japanese Patent Publication No. 406 can be cited.

The present invention can be applied not only to the rotational angular velocity of a rotating body but also to the measurement of the moving velocity of an object moving on a fixed two-dimensional or three-dimensional path.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing an example of a rotational angular velocity detection device;
Figures 4 and 5 are graphs showing the size and shape of the permanent magnet and coil, and Figures 4 and 5 are graphs showing the number of magnetic fluxes interlinking with the coil, its changes, and the electromotive force generated in the coil. , Figure 4 shows the permanent magnet and coil shown in Figure 2, Figure 5 shows the permanent magnet and coil shown in Figure 3, and Figures 6 and 7 show the Matsuhatsu Enda type optical waveguide. This is a graph showing the relationship between the voltage applied to the provided electrodes and the light intensity of the output light obtained from this optical waveguide, and Fig. 6 is a graph set so that the light intensity is maximum when no voltage is applied. Fig. 7 shows a structure in which the light intensity is set to zero when there is no applied voltage, and Figs. 8 and 9 show a structure in which the permanent magnet passes near the coil. FIG. 8 is a waveform chart showing the optical intensity of output light obtained from an optical waveguide according to various applied voltages; FIG. Figure 9 shows a structure in which the light intensity is set to zero when no voltage is applied, and Figure 10 shows the output signal waveforms of each circuit shown in Figure 1. (B) shows when the rotation speed is relatively small, and (B) shows when the rotation speed is intermediate.
Figure 11 shows the relationship between the voltage generated between both ends of the coil and the light intensity.
A diagram showing the count value of the counter at the same generated voltage and a binary number representing the finally obtained angular velocity at the same generated voltage, FIG. 12 is a block diagram showing another embodiment, and FIG. 13 is the signal processing in FIG. 12. A block diagram showing the configuration of the circuit,
FIG. 14 is a configuration diagram showing a modified example. (10)... Disc, (lll... Permanent magnet, (20
)...Electro-optic crystal substrate (light intensity modulation element), (2
1~CI! 41...Matsuhatsu Enda type optical waveguide, +
30) Coil, (41a) to (44b) Electrode, (51) to (54) Photoelectric conversion element, L)...
・Counter, (91)...CPU 0 or more Patent applicant Tateishi Electric Co., Ltd.

Claims (1)

[Claims] A magnetic flux generating section provided on one of objects that move relatively; an element that generates an electromotive force when the magnetic flux generating section passes relatively close to the other object; a plurality of elements that modulate light intensity to different degrees by applying generated electromotive force, and means for creating information regarding the speed of a moving object from changes in the light intensity of the plurality of modulated lights; Detection device for angular velocity, etc.