JPS6125068A - Detector for speed, angular velocity and the like - Google Patents

Abstract

PURPOSE:To enable highly reliable measurement and a low-loss long-range transmission without deviation in the optical axis, by arrangin a magnetic flux generator section provided on a rotor, an element for generating multiple voltage different in the value and a Mach-Zehnder type lighwage guides. CONSTITUTION:A permanent magent 11 is fixed on a rotor 10 and a coil 30 is provided which generates multiple voltates different in the value as the magnet 11 passes near it. Light form a light source is introduced into inputting lightwave guide portions 21c-24c of four Mach-Zehnder type lightwave guides 21-24 through an optical fiber 80 and a Y-shaped lightwave guides 25, 26 and 27. A pair of electrodes 41a and 41b placed on branch lightwave guide portions 21a and 21b of the lightwave guide 21 is formed on a substrate 20 and a voltage induced in the coil 30 (coil portion 31) is applied between the electrodes 41a and 41b. In this manner, the light modulated in the intensity with the lightwave guides 21-24 is converted 51-54 to electricity through optical fibers 81-84 and then, inputted into a CPU91 through 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] This invention relates to the rotational angular velocity of a rotating body, the velocity of an object periodically moving on a fixed axis, the velocity of other objects, etc. The present invention relates to a device for detecting a substance using an optical 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 to be transmitted with low loss, data can be transmitted over relatively long distances. If the data to be optically transmitted is some kind of measurement data, such as rotational angular velocity, it is preferable to measure or detect it in the form of light and then optically transmit the measurement data as it is through an optical fiber. Herein lies the value of using 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, 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 more complicated and strict optical axis alignment 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 features of optical measurement, which enable highly reliable measurement and low-loss long-distance transmission even under electromagnetic noise. It is an object of the present invention to provide a detection device for detecting speed, angular velocity, etc., which does not require such troublesome work and does not cause a situation in which measurement cannot be performed 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 magnetic flux generating part, such as a permanent magnet, provided on one relatively moving object, such as a rotating body, and fixed to the other object, such as a fixed part set. An element, for example a coil, that generates multiple voltages of different values by passing relatively close to it, and each of the multiple potential intensities derived from the light source by being applied to each of the generated multiple voltages. a plurality of light sources guided from a light source, comprising a plurality of elements modulating at different degrees and means for producing information regarding the velocity of a moving object from changes in the light intensity of the modulated plurality of lights, such as rotational angular velocity, velocity data, etc. The intensity of the light is modulated to different degrees, for example 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 using a known original 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 peripheral portion 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 rotational angular velocity detection device] In FIG. 1, a disk (10) is fixed at the center of a shaft whose rotational angular velocity is to be detected, such as the output shaft of a motor or a shaft connected thereto (as shown in the diagram). and the disc (10
) rotates together with this axis. One permanent magnet (11) is embedded around this disk (10). disk(
At any point on the trajectory of the magnet (11) that moves circularly as the magnet (10) rotates, the magnet (dashed line (
A coil (3
0) and is fixed in that position by a suitable fixing member.

The magnet (11) can also be provided on the circumferential surface of the disk (10). In this case as well, the coil (30) 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 a disc curve, the disc (10) itself is made of a ferromagnetic material, or a ferromagnetic ring is fitted around the disc (10), and the ferromagnetic material is magnetized. It's okay.

Although the coil (301) is illustrated as having a long length in FIG. 1, it is assumed that the number of magnetic flux linkages is equal in all parts of the coil (2).

This coil 00) is divided into four parts, namely (31), (3
2), (33), and (to), and the number of turns for each of these parts is n. , 11o/ 2, n, /
4 and n. /8. The coil portion (31) is the same as the entire coil (30).

The light intensity modulation element includes a Matsuhatsuenda type optical waveguide (21102+031 and (2) formed on a crystal having an electro-optic effect, for example, a L i N b Oa crystal substrate (20).
j) is an input optical waveguide portion (210), two branched optical waveguide portions (2xa) (2tb) branched from this optical waveguide portion (2ic) at equal angles, and these optical waveguide portions (21a)'C21b). It consists of an output optical waveguide section (2xd) where the two converge. Other Matsuhatsu Enda type optical waveguides (22) to (Foundation) have exactly the same configuration. In FIG. 1, the input optical waveguide portion, 2
In order to indicate the two branching optical waveguide parts and the output optical waveguide part, suffixes (a) to 02j to [24+ are used, respectively.
(d) is added.

These four Matsuha Tsuenda type optical waveguides (211~,
There are three Y-shaped optical waveguides (251 m and (
27) is formed. Light from a light source (not shown) is sent through an optical fiber (80), guided to a Y-shaped optical waveguide via a suitable optical coupler, and equally split. The two demultiplexed lights are each passed through a figure-7 optical waveguide (
26) and (2 forces re-equalize each other into two beams of equal intensity, and four Matsuhatsu Enda type optical waveguides (21) to (
24) Input optical waveguide portion = 21c) to (240)
guided by. In this way, light of equal intensity is input to the optical waveguides (21) to (24).

As an optical demultiplexer, such a Y-shaped leading waveguide block) to (2
7) You can also use something other than 7), or use 4 lights as 4 lights.
It is also possible to guide the optical waveguides (2) 1 to (24) with a real optical fiber.In any case, it is sufficient that light of equal intensity is input to the four Matsuhatsu Enda type leading waveguides (211 to (24)). However, the level discrimination circuit (6
By appropriately adjusting the discrimination levels of 1U) (61L) to (64U) (64L), it is not necessary that light of equal intensity be input to the leading waveguides (2) to 04).

A pair of electrodes (41a) and (41b) are connected to the substrate (
20) Formed on top. Pairs of electrodes are also provided on the branch leading waveguide portions of the other Matsuhatsu Enda type optical waveguides (22) to I24), respectively. These electrodes are
(42a) (42b), (43a) (431) ) and (44a) (44b). The lengths of these electrodes are all set equal.

Both ends of the coil (30) (coil portion (31)) are connected to these electrodes (21a) (21b), respectively, and the voltage induced in the coil (30) is applied between these electrodes (21a) (21b). is applied to Similarly, the voltage across the coil panel (33) and (34) is applied between electrodes (42a) (42b), (43a) (43b) and (44a) (44b), respectively.

The 7-shaped optical waveguides (25) to (2η) and the Matsuhatsu Enda type optical waveguides 011 to (24) are, for example, connected to the substrate (20).
The electrode (41
A) to (44b) are made by depositing Ar.

As will be described later, Matsuha Tsuenda type optical waveguides (21) to (
The light intensity modulated by 24) is guided to optical fibers (81) to (84), respectively, via appropriate optical couplers. Optical signals from the optical fibers (81) to (84) are converted into electrical signals by photoelectric conversion elements (51) to (54), respectively. 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-like or square-wave forms by being discriminated at such a discrimination level are sent to counters (71U).
(71L) and counted. Other photoelectric conversion elements (
The output signals of 52), (53), and (54) are similarly divided into two level discrimination circuits (62U) (62L),
(63U) (63L), (64U) (64L), and further counters (72U) (72L),
Input to (73U) (73L), (74U) (74L). The counts of these counters (71U) to (74L) are input to cPU (91) via the interface (90) every rotation of the disk (10). The counters (71U) to (74L) are reset every rotation of the disk (10) (at times other than the time period T when the magnet (11) is passing near the coil (30)). This reset signal can be obtained, for example, from another coil (the path shown) which generates an electromotive force by passing the magnet (11).

Preferably, resetting the counter and reading the count value of the counter are synchronized.

[Voltage generated in the coil]

When the disc rotates once, the magnet (11) passes near the coil (30) 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 V is generated in the coil (30) due to electromagnetic induction. occurs. This electromotive force V is given by the following equation.

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

” Coil part +311 (32+ +33
The ratio of the number of turns of + and (34) is 1:1/2:
Since it is set to 1/4:1/8, if the number of flux linkages Φ is constant in any part, the ratio of the voltages induced in these coil parts is also equal to the above ratio.

However, between the electrodes (41a) and (41b), (42aX
4211), (43a) (43)]) and (44
Voltages of V, V/2, and V/4 are applied between a) and (44b), respectively. If the number of flux linkages is not uniform in the coil (30),
By adjusting the turn ratio of each portion (31) to (circle), voltages having the above-mentioned ratios can be generated.

[Relationship between permanent magnet and 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.

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

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

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

Fig. 5 shows the interlinkage magnetic flux d Φ number Φ, its time change □, and the electromotive force V when the diameter of the surface of the magnet (11) and the diameter of the coil (3o) are almost equal (Fig. 3). ing. In this case, the magnet (11) and the coil (30)
This means that the time during which the magnetic flux linkage Φ is constant is approximately zero, and positive and negative electromotive forces V are generated in the coil (30) continuously over time.

I will proceed with the discussion based on this premise. This is because this is easier to explain than the relationship between the magnet (11) and the coil +301 as shown in FIG. However, the present invention is applicable to either the case of FIG. 2 or FIG. 3.

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

In Figure 1, four Matsuhatsu Enda type optical waveguides (2
1] to (24+) have the same structure except for the voltage applied to the electrode pair, so the Matsuhatsu Enda type optical waveguide 211 will be described as a representative of these optical waveguides.

The input optical guide liquid portion of the Matsuhatsu Enda type leading waveguide (21) (
21d). The length of the two branched optical waveguide sections (21a) (21b) is 11, l! 2 (the length from the branch point to the confluence point as shown by the broken line) is equal, the 2 waves propagating through the branch leading waveguide portions (21a) (21b)
Since the two lights are branched from one light, their phases match when they are combined in the output optical waveguide portion (21d). Therefore, without considering propagation loss,
The intensity of the light obtained at the output optical waveguide section (21d) is equal to that at the input optical waveguide section (21c). Generally speaking, branch optical waveguide portions (21a) (21b
), the two lights propagating through the output optical waveguide section (21
d), the phase difference between them is 2mπ (m is O
and an integer), the output optical waveguide (21d) obtains light with the same intensity as the light input to the Matsuhatsu Enda type optical waveguide 011 (this is referred to as maximum intensity Imax). The phase difference between the two lights is 2mπ, which means that the difference in length between the branched optical waveguide portions (21a) and (21b) is Δl=11−
12, it is expressed as follows.

λ0 Δjl'=m (2) where n is the refractive index of the optical waveguide, and λ0 is the wavelength of light in vacuum.

Difference in length Δl between the branched optical waveguide portions (21a) and (21b)
has the following relationship, these optical waveguide parts (2
When the light that has propagated through 1a) (2] and b) is combined at the output leading wavepath section (21d), the phase difference becomes (2).
m−z)π.

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

Now, since L iN b Oa is a crystal with an electro-optic effect, its refractive index changes when an electric field is applied.

For example, in the case of 2 cuts L s N b Os,
By applying a voltage to the electrodes (4xa) (, nb), the refractive index of the optical waveguide portion (2ta) (211) changes as follows.

n = n 10-n, * r33a E2]
2 2 e 2e ” r33 ・Ez ””(
41 Here, E2 is the strength of the electric field in the Z direction, n6 is the extraordinary ray refractive index, and r33 is the electro-optical constant.

As is clear from equation (4), the electrodes (41a) (4
1b), when a voltage is applied between the branch leading waveguide section (2
1a) (21b), the refractive index increases on the one hand, and the refractive index decreases on the other hand. When the refractive index changes, the optical waveguide portion (2
1a) Since the speed of light propagating through (21b) changes,
The phase difference when these lights are combined in the output optical waveguide portion (21d) changes. For example, if the length of the branched optical waveguide portions (21&) (21b) satisfies equation (2), the phase difference when the lights propagating through the branched optical waveguide portions (2Xa) (21b) are combined. is the electrode (41a)
If no voltage is applied to (41b), the light of 2mπ and the intensity Imax will be transmitted to the optical waveguide portion (21d).
However, by applying voltage to the electrodes (41m) (41b), if the phase difference of these lights becomes (2m + i)π
, the intensity of light obtained at the optical waveguide portion (21d) is O. Branch leading waveway part (21a,)
The voltage required to change the phase difference between the two lights propagating through (21b) by π is called a half-wavelength voltage V1.

FIG. 6 shows the electrode (
41a) (41b) and the output optical waveguide (
21d) shows the relationship with the intensity of light obtained. When the applied voltage is ±2 mV, light with the maximum intensity Imax is obtained, and when the applied voltage is +(2m+1)V7C, the light intensity becomes 0.

FIG. 7 shows the electrode (
4za) (411)) and the intensity of light obtained in the output optical waveguide (21d). The maximum intensity I when the applied voltage is ±(2m+1)V7t
When maximum light is obtained and the applied voltage is ±2 mV, the light intensity becomes O.

The voltage V generated in the coil (30) in FIG.
As can be seen from the equation, the number of magnetic fluxes generated by the magnet (11) (strength of the magnet (11)) and the number of turns n of the coil (30). , and changes depending on the degree of chaining. Interlinkage flux number Φ and number of turns n
. Assuming that is constant, the voltage ■ changes depending on the rotational angular velocity, and the faster the rotational angular velocity, the higher the voltage generated.

Furthermore, the phase difference of light propagating through the branched optical waveguide portion of the Matsuhatsu-Enda type leading waveguide 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.

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. Figure 8 shows a configuration in which the phase difference when the light propagating through the two branched optical waveguide sections (2ta) (21b) is combined when the voltage applied between the electrodes (ua) (41b) is 0 is 2mπ. (corresponds to equation (2) and Fig. 6), Fig. 9 shows the electrode (41a)
(41b) A configuration in which the phase difference between the two lights becomes (2m+t)π when the voltage applied between
(corresponding to the figure). Since the waveform in FIG. 8 is the same as the waveform in FIG. 9 inverted between light intensity 0 and I m a z, only FIG. 9 will be described.

As described 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. Also, the seventh
As shown in the figure, the light intensity is symmetrical with respect to positive and negative voltages with the applied voltage O as the center, and the applied voltage ■ is ±V
! At c, the light intensity shows the maximum value. Therefore, when the absolute value of the peak value of the voltage V generated by the coil (30) is less than V□, two peaks slightly shifted on the time axis appear in the light intensity, and this peak value is the maximum Strength Imax
(Fig. 9(A), solid line). And the voltage V
When the absolute value of the peak value of is 4, the peak value of the light intensity becomes the maximum intensity Imax (FIG. 9(4), broken line).

The absolute value of the peak value of the voltage V generated by the coil (30) is Vπ
If the value exceeds this value, a dent will occur at the peak portion of the light intensity waveform (see FIG. 9). This means that when the absolute value of the voltage V applied to the electrodes (41a) (41b) exceeds v9, the light intensity increases to Ima
This is because it is smaller than x (see Figure 7).

When the absolute value of the peak value of the voltage V becomes 2v7c, the above-mentioned depression decreases to the intensity 0, 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 V becomes higher, more pulse-like waveforms occur in the light intensity.

That is, when the absolute value of the peak value of voltage V becomes 3Vf, six peaks occur in the light intensity waveform.

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

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

Different voltages are applied to the electrode pairs of the Matsuhatsu Enda type optical waveguides 011 to (24), and the ratio of the applied voltages is 8:4:2:1 as described above. Therefore, the intensity waveforms of the light output from the output optical waveguide portions (21d) to (24d) of these Matsuhatsu Enda type optical waveguides 211 to 241 are also different. For example, the voltage V generated by the coil (30) Peak value is 8v.

As mentioned above, 16 peaks occur in the optical intensity waveform of the optical signal output from the output optical waveguide section (21d) when the output optical waveguide section (22d) (23d)
) and (24d) have the light intensity waveforms of 8.
Only 4 and 2 peaks appear.

[Function and effect of rotational angular velocity detection device] Fig. 10 shows
The output signals of the photoelectric conversion elements (51) to (54), the output signals of the level discrimination circuits (61U) to (64U), and the output signals of the level discrimination circuits (61L) to (64L) are shown. In the same figure (A), when the rotation speed of the disk (10) is small,
The figure (B) shows a case where the rotational speed is higher than that in the figure (A), and the figure (C) shows a case where the rotational speed is even higher. These figures all show Matsuhatsu Enda type optical waveguides 2]1 to C4.
This is under the condition that the difference in length of the branched optical waveguide section 1 satisfies equation (3) (corresponds to Figures 7 and 9)
.

The waveforms of the output signals of the photoelectric conversion elements (51) to (54) are as follows:
It has the same shape as the intensity of the light obtained in the output optical waveguide portion of the Matsuhatsu Enda type leading waveguide L21).

As is well known, the signal waveform may be inverted depending on the configuration of the photoelectric conversion element. As described above, the magnetic flux generated by the magnet (11) and the number of turns n of the coil 00). If constant, the voltage generated in the coil (30) is equal to the disc (1
0) depends on the number of rotations; the higher the number of rotations, the higher the voltage. Figure 10 (A) corresponds to the case where the absolute value of the peak value of the generated voltage V is equal to V, the figure ω) is equal to 2v5, and the figure C) is equal to 4v. 9
(see figure).

As can be seen by comparing the output signal waveforms of the photoelectric conversion elements in the signals of FIGS. 10(A) to (C'), the disk (10j
As the number of rotations increases, the time T during which the magnet (1j) passes near the coil field becomes shorter, and the number of pulse-like components 17) 1 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.

In addition, as mentioned above, the Matsuha Tsuenda type optical waveguide (2I
) to (2), the voltage ratio applied between the electrodes is 8:4:2
: 1, the pulse-like components appearing in the output signals of the photoelectric conversion elements (51) to (54) (the peak value is the maximum intensity 1
The ratio of the number of pulse-like components reaching the value V Srn a x corresponding to max also corresponds to 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.
) is level-discriminated by an upper discrimination level SU, and 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 VSmax of the output signal of the photoelectric conversion element, for example, 7 VSmax 78 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 0, for example VS
It is set to max78 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 pulse widths of the output signals of the level discrimination circuits are different from each other, the signals may be input into the counter after being converted into constant-width Norhals signals using, for example, a monostable multivibrator.

Counter (71U) ~ (74L) count value disk (10
) is taken into c P U (91) every one rotation,
stored in that memory.

Figure 11 shows the intensity of light output from the Matsuhatsu Enda type optical waveguide in the preferential condition where the voltage generated by the coil (3o) has reached its peak value, with the generated voltage on the horizontal axis and the light intensity on the vertical axis. be. For convenience, each light intensity curve is shown using the number of coil turns as a parameter. That is, no is the output light intensity of the Matsuhatsu Enda type optical waveguide 2+1,
nc/2, po/4, and no/8 are optical waveguides (2
R-CI! 31. (This is the output light intensity of 24+. As described 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 (71U) and (71L) correspond to each other, and a pair of these count values represents one piece of information. Similarly, counters (72U) and (72L), (73U) and (73L)
, (74U) and (74L) each form a pair, and the count values of the paired counters each represent one piece of information.

c P U (91) indicates that the count value of the counter with lower discrimination level SL of the pair of counters is 2.6°10
, 14.18.22.26.30. . . . and the count value of the counter with the two-part 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 An arithmetic operation is performed in which the value is set to a binary number 1, and the other cases are set to a binary number 0. 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 l.

FIG. 11 further shows 2.3.
As 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 v9, the binary number is 000
1.2v.

0010.4V when , 0100 when BV, 1000 when BV, and so on.

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 V3.

[Other Examples]

FIG. 12 shows another embodiment. In this figure, the same parts as shown in FIG. 1 are marked with the same sign, and their explanation will be omitted.

A resistor (1
Diode (01) as a rectifying element through 15)
(114) are connected to each other. As mentioned above,
Positive and negative voltages are generated in the coil (30), one of which is connected to these diodes (111) to (114).
is cut by. Therefore, the number of pulse-like components in the light intensity waveform of the output light of the Matsuhatsu Enda type optical waveguides (21) to 041 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 (10
1) will be explained.

The configuration of the signal processing circuit (101) is shown in FIG. Since the number of pulse-like components appearing in the intensity waveform of the output light of the Matsuhatsu Enda type leading waveguide 011 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 value 2.6.10.14.1 surrounded by an ellipse among the count values of the counter (71L)
The half value of 8.22.26.30... is 1.3.5.
7.9.11.13.15... and 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 if the counted value is an odd number. The output of the binary counter (106) is sent to the gate circuit (108). The comparison circuit (107) has a counter (71U) and (7
When the count value of the counter (7iU) is equal to or larger than the count value of the counter (71L), a signal is output to open the gate of the gate circuit (108). Therefore, the gate circuit (108)
When the pair of count values of the counters (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.

In FIG. 12, the latch circuit (105) is connected to the output signals of the signal processing circuits (101) to (104) (the gate circuit (105)
08) etc.), the magnet (11) is connected to the coil (30
) is stored temporarily after passing through the vicinity. It will be easily understood that the output signal of the latch circuit (105) represents the four-digit binary number shown in FIG.

This embodiment has the advantage that it is possible to obtain a signal representing the angular velocity of the disc in a digital quantity using a hard circuit without requiring processing by the CPU (91).

[Modified example]

” In the second embodiment, one permanent magnet (1
1), but a plurality of permanent magnets may be provided at equal angular intervals. Alternatively, coils having different numbers of windings may be made to correspond to one or more magnets, and both ends of each coil may be connected to electrodes provided on each Matsuhatsu Enda type optical waveguide. Furthermore, the number of coils and permanent magnets may be arbitrary.

In FIG. 14, eight permanent magnets (11) of equal strength are provided around a disk (10) at equal angular intervals. Corresponding to these permanent magnets (II), the number of turns or no,
nc/2, ne/4, n, /8, no/ 16, n
o/32, nc/64, no/128 of 8
A number of coils (30) are arranged and connected to electrodes of a Matsuhatsu Enda type leading waveguide formed on the substrate (support).

It is also possible to keep the number of turns of the coil constant and vary the strength of the permanent magnet (or the number of magnetic fluxes generated).

The substrate (20) may be any material as long as it has an electro-optic effect in which the refractive index changes when an electric field is applied. Therefore, the optical waveguide may be formed using various techniques depending on the type of substrate other than thermal diffusion of Ti. It can be made depending on the material. Since the electrode changes the refractive index of the optical waveguide portion by applying a voltage, it can take various shapes, arrangements, and states depending on the properties of the substrate. For example, the electrodes may be arranged so as to sandwich one branch leading 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 A/, 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 measurement of 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 drawings]

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. , Fig. 4 shows a model using the permanent magnet and coil shown in Fig. 2, Fig. 5 shows a model using the permanent magnet and coil shown in Fig. 3, and Figs. 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. Figure 11 shows the case where the rotation speed is relatively low, Figure 1 (C) shows the case where the rotation speed is intermediate, Figure 11 shows the case where the rotation speed is relatively high, and Figure 11 shows the generation between the coil ends. A diagram showing the relationship between voltage and light intensity, a counter count value at the same generated voltage, and a binary number representing the finally obtained angular velocity at the same generated voltage. FIG. 12 is a configuration diagram showing another embodiment.
This figure is a block diagram showing the configuration of the signal processing circuit in FIG. 12, and FIG. 14 is a configuration diagram showing a modified example. (10)...Disc, (11)...Permanent magnet, (20
)...Electro-optic crystal substrate (light intensity modulation element), 011
~(24)...Matsuha Tsuenda type optical waveguide, (scream・-
・Coil, +3]) ~ +34) ---: Iil part, (41a) ~ (44b) --- Electrode, (51) ~
(54)...Photoelectric conversion element, (61U) to (64L)
...Level discrimination@road, (71U) ~ (74L)-#0
Counter, (91) --- CPU U0 or more Fig. 6 rhow pressure Fig. 8 JP-A-6L-25068 (15) 甫'7 L'-,! @Figure 9

Claims (1)

[Claims] A magnetic flux generating section provided on one of the relatively moving objects, and a magnetic flux generating section provided on the other object that generates a plurality of voltages of different values by passing relatively near the magnetic flux generating section. A plurality of elements that modulate light intensity to different degrees by applying the plurality of generated voltages to each of them; A means for creating information regarding the speed of a moving object from changes in the light intensity of the plurality of modulated lights. A detection device for speed, angular velocity, etc., equipped with .