JPS58202873A - Optical rotation detector - Google Patents

Abstract

PURPOSE:To enable the detection of information on motor rotation by obtaining two sets each of reverse phase signals with the rotation of a rotary plate from two photoelectric conversion means comprising photoelectric conversion elements separated radially over the entire periphery and electrodes for electrically connecting the elements. CONSTITUTION:Light from a flat light source 13 is shielded with a rotary plate 14 while irradiating a first photoelectric conversion element 19b and 19a alternately through a first slit 17a of the rotary plate 14 and hence, it is allowed to irradiate the conversion elements 19a and 19b in the opposite phase to each other. This light is applied to an arithmetic amplifier and a photoelectro-motive current-voltage conversion circuit to obtain voltages Va and Vb in the elements 19a and 19b in proportion to the quantity of irradiated light. The voltages Va and Vb are opposite in the phase. When these voltages are applied to a differential amplification circuit, they cancel noises of the same phase as those to increase signals thereby producing signals with a high signal-noise ratio. This enables accurate detection of information on the motor rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small-sized, high-precision optical rotation detection device, and is suitable for a rotation detection device for electronic commutator motors, particularly DC brushless motors.

In recent years, high-performance and highly reliable DC brushless motors have come into widespread use as motors for audio and video equipment.

These DC brushless motors use a multi-pole magnetized rotor magnet as a rotor and a stator coil as a stator.

These DC brushless motors usually include a frequency generator (hereinafter referred to as F-G) for detecting rotational information such as rotational speed and rotational phase, and a rotor magnet, which allows the motor to effectively generate torque. A rotor position detection element is provided to perform an electronic rectification function to control the current supply to the stator coil in accordance with the rotational position of the rotor, and conventionally magnetic type elements have been used for these elements.

A DC brushless motor equipped with a conventional rotor position detection element will be explained with reference to FIGS. 1 to 4.

Figure 1 shows a vertical cross section of a DC brushless motor.
1 is a rotary shaft, 2 is a letter pairing attached to the rotary shaft 1, 3 is a support member for the bearing 2, 4 is a rotor magnet, 6 is a rotor yoke, and the rotor magnet 4 is attached to the rotor yoke 5. At the same time, the rotor yoke 6 is configured to be coupled to the rotating shaft 1 and rotate together.

The rotor magnet 4 uses a permanent magnet magnetized with multiple poles, and as shown in FIG. It is magnetized like this.

The master stator coil is the stator coil board 6'1'□
: As shown in Fig. 3, coil blocks C1 and 02 made of conductors are arranged at positions that are integral multiples of 1800 in electrical angle with respect to the magnetic field of the rotor magnet 4. A coil block consisting of conductors that are connected in series to form a first stator coil and are similarly arranged at positions that are an integral multiple of 180 degrees in electrical angle with respect to the magnetic field of the rotor magnet 4. C3 and 04 are connected in series to form a second stator coil.

These first and second stator coils are arranged to face the rotor magnet 4 and are arranged at positions that differ from each other by an odd multiple of 90 degrees in electrical angle. Also, coil block C<.

C2, Cs and C4 each have a width of 1800 in electrical angle.

The electrical angle is the rotor magnet 4ON as shown in Figure 2.
Assuming that the angle for one period of magnetization between the pole and the S pole is 3600, the angle of the entire circumference of the 6FM magnetized rotor magnet 4 as shown in Fig. 2 (360' in mechanical angle) is It has the following value in i% angle.

360° x (6 poles/2) = 1080' Furthermore, the stator coil board 6 is provided with a position where the positional relationship between the first and second stator coils and the rotor magnet 4 can be detected and the motor can generate effective torque. Two Hall elements 7 and 8 are provided as rotor position detection elements that function as electronic commutators to control the current flow to the stake coils, and these Hall elements 7 and 8 detect the rotor magnet 4. The rotational position is detected by obtaining a voltage that is sensitive to the generated magnetic field.

As shown in FIGS. 1 and 4, at the bottom of the stator fill substrate 6, a permanent magnet 9 is magnetized with N and S poles in the axial direction, and a tooth pattern is cut on the inner periphery. Stator yoke 10
, a rotor gear 11 provided inside the stator yoke 1° and connected to the rotating shaft 1 and having a tooth pattern cut on its outer periphery, and an FG coil 12 wound around the outside of the permanent magnet 9. A circumferentially opposed magnetic FG is attached.

The stator yoke 10 and the rotor gear 11 are both made of a magnetic material, have the same number of teeth k (k is a positive integer), and are configured such that the teeth face each other, and together with the permanent magnet 9 form a magnetic circuit. However, when the rotor gear 11 rotates and the tooth-shaped peaks of the stator yoke 1o face each other, the magnetic resistance becomes smaller and the magnetic flux generated from the permanent magnet 9 flows more easily. When the valleys face each other, the magnetic resistance increases, making it difficult for the magnetic flux to flow, and the amount of flowing magnetic flux changes alternately, creating an AC voltage at both ends of the FC winding 12 that has a voltage proportional to the differential value of the amount of change in magnetic flux. induced. The frequency fWG of the AC voltage induced across the FG winding 12 is twice the rotation frequency of the rotating shaft 1 (k is the number of teeth), and the rotation speed is detected using this frequency fFG.

First of all, the performance required for FG is ■Detection accuracy is hardly affected by processing or assembly.

■High detection frequency can be obtained even during low speed rotation.

■When a high output voltage is obtained, it is also resistant to external noise and induction. □ ■The FG itself should not generate noise and adversely affect other circuits.

■The FG itself does not generate uneven rotation or vibration.

■Simple structure allows for miniaturization.

etc. can be mentioned.

Now, in the case of FGs like those shown in Figures 1 and 4 above, since they are of the all-around facing type, the detection accuracy is not easily affected by machining or assembly, allowing for highly accurate detection, but on the other hand, machining is difficult. Also, since the change in magnetic resistance becomes small, the pitch of the tooth pattern cannot be made small, making it impossible to create a compact device with a high detection frequency. In addition, in the case of this type of magnetic FG, the FG
Since the voltage induced in the coil is proportional to the time-differentiated change in the magnetic flux interlinking with the FG coil, a high output voltage cannot be obtained during low-speed rotation, and at the same time, the FG coil is affected by the magnetic flux of the rotor magnet. Noise such as induction noise from the current flowing to the stake coil is likely to be superimposed, and the S/N ratio of the detection signal deteriorates, resulting in deterioration of detection accuracy. In the case of this magnetic FG, the leakage magnetic flux generated outside the motor is
It fluctuates due to changes in magnetic resistance caused by the rotation of the FG's rotor gear.For example, in a portable VTR, where the audio signal playback head is close to the capstan motor
When these magnetic type FGs are used in a capstan motor, fluctuations in the leakage magnetic flux affect the reproducing head and cause deterioration of the S/N ratio of the reproduced signal, resulting in undesirable results. Furthermore, in the case of a full-circumference opposed magnetic type FG as shown in Figs. 1 and 4, the magnetic attraction force of the opposing teeth causes vibrations when the motor rotates, making the rotation unstable and causing uneven rotation. There are disadvantages such as the occurrence of

Next, regarding the rotor position detection element, in the conventional magnetic type shown in Fig. 3, in which the Hall element is arranged on the stator coil board, the Hall element is usually attached to the board by visually soldering it. Furthermore, since the Hall element itself is molded in plastic, the positional accuracy of the internal Hall element with respect to the molded package is not guaranteed, and the mounting accuracy cannot be improved.

For this reason, the position detection accuracy is poor, and when performing electronic commutation, the timing of energizing the stator coil is shifted, causing rotational unevenness and causing undesirable results.

Furthermore, in the case of DC brushless motors, the way the current flows through the system stake coils differs depending on the drive method; for example,
Various waveforms have been proposed, such as sine waves and rectangular waves, but - Usually, the waveform of the current flowing to the stake coil is determined by the detection waveform of the rotor position detection element, and the rotor position detection element generates these waveforms. If so, it can be easily achieved. However, with the Hall element shown in Figure 3, the generated voltage is determined by the magnetic field generated by the rotor magnet, making it difficult to obtain an arbitrary waveform and making it impossible to freely change the current flowing through the stake coil. It had drawbacks.

In the case of the U' magnetic type shown in Fig. 3, the Hall element must be placed on the same board as the stator coil, which is not possible with the 2-phase-4 coil shown in Fig. 3! This is not a problem, but in devices that have a larger number of phases and coils, have a more complex structure, and require miniaturization, they have the disadvantage that the Hall element gets in the way of the stator coil arrangement.

As described above, conventional magnetic FC and rotor position detection elements have many drawbacks.

In view of the drawbacks of the conventional example, the present invention provides an FG that is small, high output, has a high detection frequency and a good S/N ratio, has high detection accuracy, can obtain a free detection waveform, and has a high detection frequency. An optical rotation sensing device for an electronic commutator motor is provided that includes a rotor rotational position element that is unobtrusive in its arrangement.

An embodiment in which the optical rotation detection device of the present invention is applied to a DC brushless motor is shown in FIGS. 6 to 16.
This will be explained based on the diagram.

FIG. 5 shows a longitudinal section of an embodiment of a DC brushless motor to which the optical rotation detection device according to the present invention is applied. As in FIG. 1, 1 is the rotating shaft, 2 is the bearing, and 3 is the bearing 2 The supporting members include a rotor magnet 4, a rotor yoke 5, and a stator coil substrate 6. As the rotor magnet 4, a permanent magnet 1 magnetized with six poles is used in the same manner as shown in FIG. In addition, the stator coil board 6 is also attached with coil blocks C+, C2, C3, and C4 in the same manner as in FIG.
A second stator coil is formed by connecting the
The difference from the one shown in FIG. 3 is that no Hall element is attached.

In Fig. 5, the configuration up to this point is the first one except that the Hall element is not attached to the stator coil board.
Same as the figure.

Now, in FIG. 6, an optical rotational position detection device according to an embodiment of the present invention is attached to the lower part of the stator coil board 6.

This optical rotational position detection device includes a flat light source '13,
It is composed of 4 rotating plates and 16 planar photoelectric conversion elements. The planar light source 13 is fixed to the stator coil substrate 6, the planar photoelectric conversion element 15 is fixed by a support member 16, and the rotating plate 14' is coupled to the rotating shaft 1 and rotates together.

The rotating plate 14 is provided with Q47 FG which faces the entire circumference by optical means.
A first frit group 17 arranged in a ring shape is hatched on the outer periphery of FIG. 6 to realize this, and a second slit is hatched inside for detecting the rotor position by optical means. 181L, 18b, and 180 are provided, and the first frit group 17 has a small frit in the radial direction range from radius r3 to r4, as shown in FIG. 8 (FIG. 8 is a partially enlarged view of FIG. 6). Nuri) 171L are provided at equal intervals over the entire circumference. The second slits 181Ll 18b and 180 are provided in the radial range from radius r1 to r2 at an electrical angle of 18o0 where the rotor magnet 4 is magnetized to the S pole, and the number of the second slits is equal to The number of poles, the number of magnetized poles, 6 in the case of Figure 6
Since it is polarized, there are three second slits 18a and 18b.
, 18a are provided. In addition, in FIG. 6 and FIG.
Assume that the portion of the image is transparent. The rotating plate 14 is, for example,
A thin metal film is deposited on a glass disk and then photo-etched. Alternatively, it can be realized by providing slits in a thin disk of stainless steel by photo-etching.

The planar photoelectric conversion element 15 is connected to a first photoelectric conversion element 19 shown by hatching on the outer periphery of FIG. 7, which is used to realize a full-circumference facing type FG, and a rotor position detection element 19 is formed by optical means. A second photoelectric conversion element 2 is installed inside it to perform
0.21 is provided, and the first photoelectric conversion element 19 has an electrode pattern in a radial range from radius r5 to r4, as shown in FIG. 9 (FIG. 9 is a partially enlarged view of FIG. 7). Photoelectric conversion element small piece 19 connected to 19a'! N photoelectric conversion element pieces B19b connected to the electrodes B19b' are alternately arranged at equal intervals along the entire circumference. Pitch P2 of the photoelectric conversion element small piece M 19a and the photoelectric conversion element small piece B19b shown in FIG.
is the first slit 171L of the rotating plate 14 shown in FIG.
The photoelectric conversion element small piece 191L and the photoelectric conversion element small piece B19b are electrically separated, and each independently generates a photovoltaic current proportional to the amount of irradiated light between the electrode 191' and the electrode 191'. It can be taken out from B19b'.

In FIG. 6, the plane light source 13 is directed toward the bottom of the figure and irradiates light all around the radius range from r1 to r4 where the slit is formed.

In this case, the light 131L emitted from the plane light source 13 is transmitted to the rotating plate 1.
4, while the first sulin of the rotary plate 14) 1
71L to the first photoelectric conversion element 19, and since the rotating plate 14 rotates together with the rotating shaft 1, the first
As shown in Figure 2b, the first photoelectric conversion element 19
The case of the same figure a where the photoelectric conversion element small piece B19b forming one part is irradiated and the photoelectric conversion element small piece A191L forming the other is not irradiated, and the case of the same case where the photoelectric conversion element small piece B19b is irradiated with the photoelectric conversion element small piece B19b forming the other side. The state shown in the figure occurs alternately every time the first sulin 117a of the rotating plate 14 rotates by 1 pitch P1.

Therefore, when the rotary motion 4 rotates, the photoelectric conversion element small piece 191L and the photoelectric conversion element small piece B19b are irradiated with light of opposite phase, and this is transmitted to the operational amplifier A1 as shown in 22.23 in FIG. 24- and resistors R1, R
The 11th
As shown in the figure, a voltage Va proportional to the amount of light irradiated by the photoelectric conversion element small piece 19a and a voltage vb proportional to the amount of irradiated light given to the photoelectric conversion element small piece B19 are obtained. In addition, in the photovoltaic current-voltage conversion circuit shown in FIG. 12, when the photoelectric conversion element is irradiated with light and a photovoltaic current is generated, a negative voltage proportional to the photovoltaic current is generated. Voltages vIL and vb are voltages with opposite phases to each other, and the DC value is Va.
o and Vbo, the voltages of the signal components become Tap-p and Vbp-p.

These voltages V& and vb are connected to operational amplifier A3 and resistor R3゜R.
4, R3', R4' (Rs2R4= Rs'2R4
'), and by taking the difference between the two, the first
The DC value v00 as shown in Figure 1 is canceled out and decreases to Woo = Ka (Vao-Tho), while the voltage Vop-p of the signal component is Vop-p =
KO (Yap-p +Vbp-p) and an increasing output signal vo is obtained.

This output signal Vo is used as a rotation information detection signal such as a speed detection signal or a phase detection signal.
, Wb is canceled out and reduced by taking the difference between them, and the signal increases, so that a signal with a high S/N ratio can be obtained.

In addition, in Figure $7, coil blocks 01 to C4 are indicated by broken lines, but these coil blocks C1, C2,
Os and C4 are not provided on the planar photoelectric conversion element 16, but are provided on the stator coil substrate 6, and the ones drawn with broken lines in the figure are the second photoelectric conversion elements 20 and 21. This is to show the positional relationship with

And, as shown in FIG. 9, the 20th photoelectric conversion element 20 is
It consists of a small photoelectric conversion element C2oC connected to an electrode 5c2oc' and an electrode C200', and a photovoltaic current proportional to the amount of irradiated light can be taken out from the electrode C20C'.

Therefore, the light emitted from the plane light source 13 is transmitted to the rotating plate 1.
When the second slit 181L, 18b or 180 of No. 4 is located on the second photoelectric conversion element 20, the light is projected onto the second photoelectric conversion element 20 through the second slit 181L, 18b, 180, and 2 slits 18t, 18
When b or 18c is not located above the second photoelectric conversion element 2o, the second photoelectric conversion element 20 is not irradiated with light,
During one rotation of the rotary plate 14, the state in which light is irradiated to the second photoelectric conversion element 2o and the state in which it is not irradiated are repeated three times.

Further, the other second photoelectric conversion element 21 is located at a position away from the second photoelectric conversion element 20 by an odd multiple of 90 degrees in electrical angle (270' in FIG. 7), and the rotating plate rotates 140 times. At this time, the light irradiated to the 20th photoelectric conversion element 21 is shifted by 90' in electrical angle from the light irradiated to the second photoelectric conversion element 20.

In this case, as shown in FIG. 13, the second photoelectric conversion element 20
．． 21 is an operational amplifier A4. 5 and resistor R5, R
6 through a photovoltaic power-to-voltage conversion circuit similar to that shown in FIG.
0 photovoltaic current converted to voltage) and VF6 (
A rotor position detection signal having a phase difference of eo' at the angle is obtained as shown in the photovoltaic current of the second photoelectric conversion element 21 converted into voltage.

Now, in Figure 7, Caa, Cab, C21
L, C2b.

Osh, C3b, C4a, and Cab are each made of a conductor from the coil block 01. C2, Os, C
This shows the conductors located in the radial direction in a, and the conductors C+a, C1b, and C21L located in the radial direction contribute to the generation of torque in the simulator.

Currents flowing through C2b, C3&, Csb, C41L, and C4b, and the second photoelectric conversion element 20.21
are located at odd multiples of electrical angle of 90°,
Also, they are located at positions delayed by 46 degrees in electrical angle from conductors OAN and 02a, respectively.

This second photoelectric conversion element 20.21, like the Hall element of the conventional example, detects the positional relationship between the stator coil and rotor magnet 4 so that the motor effectively generates torque, and detects the positional relationship between the stator coil and the rotor magnet 4, and converts the coil block G1. C2, Cjs.

Conductors 01a, Cab, located in the radial direction of C4
02a.

C2b, Csa, Csb, C41L,
Coil block C+ is at the point where the magnetic flux of rotor magnet 4 intersecting with Cab is maximum.

Conductors 01a, Cab, 02& located in the radial direction of the coil blocks C+, C2 forming the first stator coil are provided to perform an electronic commutator action for energizing 02, Cs, Qa.
, C2b and the conductors C5a, Csb, Ca located in the radial direction of the coil block Os, 04 forming the second stator coil.
a, the magnetic flux interlinking with C4b is φ2, the positional relationship of the rotor magnet 4 with respect to the stator coil shown in FIGS. 6 and 7 is 00, and the rotor magnet 40 rotation angle θR (θR is an electrical angle in a clockwise direction ) with respect to the magnetic flux linkage φ1. When φ2 is shown, φ1 in FIG. φ2
The result is an alternating magnetic field corresponding to the rotation angle θR.

In other words, in the first stator coil, θR=O°
and conductors C11L, C1b, C+a, Czb
is near the boundary between the S and N poles of the rotor magnet 4, and φ1 becomes zero, and as θR increases, φ1 also increases, and θR
=90° conductor 01a, Cab + 02a
, C2b is located near the center of the S and N poles of the rotor magnet 4, φ1 is maximum, and θR: 1
At 80°, the conductors C1a, C1b,
Cza and C2b are the S and N poles of the rotor machining net 4.
It is located near the polar boundary and becomes zero again, θR) 18Qo
``'' conductors Cl2L, C1b, C21L.

If the magnetic flux that intersects C2b is in the opposite direction to 0°〈θR (1so', and this is the negative direction, θg=2706
Although the polarity is opposite to θR=90', the conductors C+a, C
1b.

C21L and C2b are located near the center of the S and N poles of the rotor magnet 4, and φ1 is the maximum negative value. As shown in φ1, θR=0°~36
It shows a sinusoidal change with one cycle being 0°.

Similarly, in the second stator coil, since the coil blocks Os and C4 that constitute these are arranged at a position shifted by 90' in electrical angle from the first stator coil, φ2 is also shifted by 900' from φ1. The waveform becomes as shown in FIG. 12.

Now, regarding the second photoelectric conversion elements 20 and 21, these are 46 degrees electrical angle with respect to the stator coil as described above.
The operational amplifiers 4. 5 and resistance Rs.

When converted into a voltage by a photovoltaic current-voltage conversion circuit similar to that shown in FIG. 12, consisting of R6, the output voltages Vp+ and Vp2 become φ as shown in vpl, Vl)2 in FIG.
1. The waveforms are shifted by 46° with respect to φ2.

These voltages vp1 and vp2 are passed through a waveform shaping circuit and Vp
+ shaped signal v1 and Vl)2 shaped signal v
2 is obtained, Vl and V2 are passed through a logic circuit, and according to the output signal of this logic circuit, a current 11 to be energized to the first stator coil and a current I2 to be energized to the second stator coil.
As shown in Fig. 14, the process 1 is corrected in the 90' interval from θR-45° to 136° (the interval where V+ is "1" and v2 is "0") where φ1 reaches its maximum positive value. flow in the direction,
θR where φ2 has the maximum positive value: 9 from 135° to 225°
In the 00 Yoshikawa (section where vl is "1" and v2 is "1"), work 2 flows in the positive direction, and θR= where φ1 becomes the maximum negative value.
90° interval from 225° to 316° (vl is '0' and v2
is "'1" section), flow workpiece 1 in the opposite direction, and φ2
is the maximum negative value θR = 315° (or -46°) ~
In the 90' section of 46 degrees (the section where V+ is "0" and v2 is "0"), I2 is caused to flow in the opposite direction, and energization control, that is, electronic commutator action, is performed so that the current caused by energization effectively contributes to torque generation. Now, source planar photoelectric conversion elements can be realized by semiconductor photoelectric conversion elements. It can be divided into those that utilize the photovoltaic effect, which can generate an electromotive force and obtain a photovoltaic source by irradiating the photovoltaic material.

In an optical rotation detection device such as the present invention, it is generally desirable to have a small size and low power consumption, and for this reason, a weak light source such as a light emitting diode is used as the light source.

Therefore, compared to the case where the ratio of dark current to the current obtained during weak light irradiation is large, such as due to the photoconductive effect,
Due to the photovoltaic effect, it is preferable to extract the photoelectric conversion element using a photovoltaic current-voltage conversion circuit as shown in FIG. 12.

If this photovoltaic current-voltage conversion circuit is used, the voltage across the photoelectric conversion element will be approximately zero volts, which is close to a short-circuit condition, suppressing the generation of dark current and providing a stable detection signal even in weak light. .

Now, the method A for realizing a thin planar photoelectric conversion element having a photovoltaic effect is a single-crystal silicon photoelectric conversion element called a photodiode, a haselen photoelectric conversion element, an amorphous silicon photoelectric conversion element (hereinafter referred to as a-S
i Abbreviated to photoelectric conversion element. ), various photoelectric conversion elements are conceivable, but the properties required of the photoelectric conversion element used in the present invention are: (1) the ability to provide a large-area photoelectric conversion element at low cost;

- Microfabrication is possible, many independent elements can be formed on the same substrate, and these elements can be easily combined and separated.

■High sensitivity.

■Fast response.

■Wide operating temperature range.

■Small variation in elements.

etc. are listed.

First, the single-crystal silicon photoelectric conversion element can almost satisfy the above-mentioned conditions (1) to (4), but it becomes expensive when the area is increased.

In addition, selenium photoelectric conversion elements and other CdS photoelectric conversion elements can realize large area T at low cost, but on the other hand, it is difficult to perform microfabrication by photoetching □, etc. and 19b is for example convergence 10
At about 0 μm, the width of the separation zone is 10 to several 10 mm. If it is on the order of czm, it is difficult to realize with these photoelectric conversion elements. or,
Selenium photoelectric conversion elements, etc. have lower sensitivity than the a-Si photoelectric conversion elements described later, their response is nearly an order of magnitude slower, and the variation between elements is very large, so they cannot be used as the charging conversion element of the present invention except in special cases. not appropriate.

On the other hand, the a-8i photoelectric conversion element can provide a large-area, thin, flat photoelectric conversion element at low cost, and can form a large number of independent photoelectric conversion elements on the same substrate by removing the transparent electrode by photoetching, etc., which will be described later. No. 9 that can be microfabricated
A photoelectric conversion element as shown in the figure can be provided.

In addition, the sensitivity is high, and it is possible to obtain a sufficient output signal even with weak light such as when the light source is composed of a light emitting diode. It is possible to sufficiently meet the required responsiveness.

Furthermore, the operating temperature range is wide, and the above-described changes in sensitivity and responsiveness are small and the necessary performance can be maintained over a wide range of 80° C. or higher and -60° C. or lower.

Not only those formed on the same substrate but also those formed on different substrates have small variations between elements and are excellent in productivity.

As is clear from the above description, the planar photoelectric conversion element applied to the optical rotation detection device of the present invention includes &-S
The i photoelectric conversion element is optimal.

Now,! A brief explanation of the L-8i photoelectric conversion element will be given using an example.

FIG. 16 shows an example of an a-Si photoelectric conversion element that can be applied to the present invention. This is an enlarged view.

Also, the same figure is a plan view of the first photoelectric conversion element 19 (
Fig. 16 is a view seen from the direction of the arrow mark of the turtle), and C in the same figure is a line segment indicated by a dashed-dotted line. A vertical cross-sectional view when broken at −〇′ is shown.

In FIG. 16a, a hydrogenated amorphous silicon thin film 26 (hereinafter abbreviated as a-Si+H film) with a PiN junction is formed on a transparent lower electrode 26 made of a stainless steel substrate or the like and serving as a base. Indium tin oxide 27 (hereinafter referred to as IT) indicated by diagonal lines on the a-8i+H film 26
Abbreviated as O. ) has a transparent electrode attached to it.

This a-3i;H film 26 forms a pin junction between the lower electrode 26 and the ITO 27, as shown in FIGS. Works as a photoelectric conversion element.

Not only does the non-adhered part not function as a photoelectric conversion element, the resistivity of the a-8i+H film 26 is high, the film thickness is several thousand people, and the ITO film 26 is thin. When the width of the blank part is several μm to several tens of μm, it is sufficiently longer than the thickness of the film and has a large resistance value in the lateral and direction, so it acts as an electrical insulator.
As shown in Figures a, b, and c (when ITO 27 is attached in the form of separate islands, independent photoelectric conversion element pieces 19 and 1 with the lower electrode 26 as a common electrode)
9b can be formed.

A method of attaching ITO 27 in isolated islands can be realized, for example, by applying ITO 27 to the entire surface of the a-8i thin film 26, and then removing unnecessary ITO 27 in the area where a separation band is desired to be formed by photo-etching. In addition, these separately formed attached parts of ITO27 not only function as independent photoelectric conversion elements, but also serve as electrodes made of aluminum or the like using stiff straw, as shown in Figures 16a and b or Figure 9. A19a' and electrode B1
9b', and a photoelectric conversion element that requires microfabrication as shown in FIG. 9 can be easily realized.

In addition, in the photoelectric conversion elements shown in FIGS. 15a, b, and c, the lower electrode 26 serves as a common electrode for the cathode, as shown in FIG.
b' become anodes separated from each other.

Moreover, the a-Si photoelectric conversion element as explained above usually has 5
Since the peak wavelength sensitivity is around 700 people, it is preferable to use a light source with a wavelength around 5760 people. 57
As a light source having an emission wavelength in the vicinity of 0000, for example, an orange light emitting diode (emission wavelength path 63oO) or a green light emitting all-optical diode (emission wavelength path 5660) is used.
This can be realized using visible light emitting diodes such as .

Now, one embodiment of the optical rotation detection element according to the present invention has been described above, but the present invention forms a surface-facing FG over the entire circumference or substantially the entire circumference by optical means, and A rotor rotational position detecting means is formed to perform an electronic rectification effect at a position in the direction.
The present invention is not limited to the DC brushless motor as shown in the figure, but can be applied to any motor that requires an FG and rotor rotational position detection means, regardless of the type of motor, drive method, etc.

In addition, in the present embodiment, an electrician 1 that energizes the first stator coil and an electrician 2 that energizes the second stator coil.
An example has been described in which each waveform is rectangular; however, in the case of the present invention, the second slits Ia&, 1ab
, 1sC shape or second photoelectric conversion element 20.21
Alternatively, it is possible to obtain an arbitrary detection waveform by changing the shapes of both; for example, in a DC brushless motor with a two-phase stator coil configuration, the rotor magnet is magnetized in a sinusoidal manner, and the first stator coil is A sine wave (Sin wave) current is passed, and a cosine g1. (cQs wave) current having a phase difference of 90' is applied to the second stator coil located at a position 900 degrees apart by 1 + i air angle. Although drive systems for suppressing flow torque ripple have also been proposed, the present invention can be applied to these drive systems and exhibits its effects because it is easy to obtain a detection waveform of an arbitrary shape.

In the above embodiment, an example was shown in which the first photoelectric conversion element was provided over the entire circumference, but even if it is not provided over the entire circumference, if it is provided over substantially the entire circumference, the same effect as the entire circumference can be obtained. This is advantageous in that it is possible to obtain detection accuracy and to take out the electrode wire etc. from the part where the first photoelectric conversion element is not formed. Alternatively, a third photoelectric conversion element used for another purpose (for example, a phase difference of 90' with respect to the first photoelectric conversion element 19 is added to the part where the first photoelectric conversion element is not formed,
(used for determining the rotation direction) may also be formed.

Although the a-5i photoelectric conversion element is most suitable as the planar photoelectric conversion element of the present invention, other photoelectric conversion elements such as S6 photoelectric conversion element and single crystal silicon photoelectric conversion element may also be used as the photoelectric conversion element of the present invention. Applicable. In addition, not only a photoelectric conversion element based on the photovoltaic effect but also a photoelectric conversion element based on the photoconductive effect can be applied as the photoelectric conversion element of the present invention.

In the embodiment of the present invention, the first
The pitch P2 of the photoelectric conversion element small pieces 19a and photoelectric conversion element small pieces B19b forming the photoelectric conversion element is equal to the slit pitch P1 of the first slit 17a of the rotary plate 14 shown in FIG. Two photoelectric conversion element pieces 191L and photoelectric conversion element pieces B1
Although the example in which the photoelectric conversion element 9b is provided has been described, the present invention may also use a first photoelectric conversion element having a configuration in which two or more sets of photoelectric conversion element pieces are provided in the slit pitch P1. , :, ゛For example, when it is desired to obtain two types of signals with a 90° phase difference with high accuracy in order to perform the rotational direction M++, four photoelectric conversion element pieces are placed in the width of the slit pitch P1 of the rotating plate 14. Provided at intervals over the entire circumference or almost the entire circumference, and with a pitch P
At the angle where 2 is 360°, the first photoelectric conversion element piece is the reference 00, the second photoelectric conversion element piece is 90°, the third photoelectric conversion element piece is 1800. The fourth photoelectric conversion element piece is Using the first photoelectric conversion element placed at a position shifted by 270' (the fourth photoelectric conversion element piece is 180° with respect to the second photoelectric conversion element piece), the photovoltaic current of these photoelectric conversion element pieces is , is converted into a voltage by a photovoltaic current-voltage conversion circuit as shown in FIG. 12, and a voltage e1.2 corresponding to the photovoltaic current of the first photoelectric conversion element piece
Voltage e2 corresponding to the photovoltaic current of the th photoelectric conversion element small piece
．． Light from the third photoelectric conversion element.

A voltage e3 corresponding to the electromotive current and a voltage e4 corresponding to the photovoltaic current of the fourth photoelectric conversion element small piece are obtained, and this voltage e1
．． e2. e3. Voltage es which is the difference signal of e4 =
Obtaining e1-e3 and voltage e6=e2-e4,
The relationship between e5 and e6 is such that when the pitch P1 is 360 degrees, a signal with a phase difference of 90 degrees in angle and a high S/N ratio with DC components and common mode noise canceled can be obtained.

Further, as the first photoelectric conversion element of the present invention, only one using two or more sets of photoelectric conversion element pieces is used, and one photoelectric conversion element piece is used in the slit pitch P1 of the first slit of the rotating plate. The photovoltaic current generated by the photoelectric conversion element small piece is
It is also possible to convert the photovoltaic current into a voltage using a photovoltaic current-to-voltage conversion circuit as shown in FIG. 2 to obtain a voltage as shown in Va or vb in FIG. 11, and detect rotation information using this voltage.

Furthermore, in the present invention, in addition to the first photoelectric conversion element and the second photoelectric conversion element, a signal for obtaining an absolute phase detection signal indicating a voltage change of one cycle per one rotation of the electronic commutator motor is provided. In the planar photoelectric conversion element, a third slit may be provided on the third photoelectric conversion element and the rotating plate.

According to the present invention as described above, the following effects can be obtained.

(2) Since the photoelectric conversion element for FG for detecting rotation information and the photoelectric conversion element for detecting rotor rotational position can be formed on the same planar photoelectric conversion means, a compact rotation detection device can be provided.

■ Since the FG that detects rotation information is formed over the entire circumference or almost the entire circumference, a signal integrated over the entire circumference is obtained, and mechanical precision defects are integrated over the entire circumference, so the FG An optical rotation detection device whose detection accuracy is not easily affected by processing or assembly can be provided.

■ The FG that detects rotational information is composed of a light source, a first slit on the rotary plate, and a first photoelectric conversion element on a planar photoelectric conversion element, and the pitch of these elements can be made small. Yes, high detection frequency can be obtained even at low speed rotation.

■ Since the FG that detects rotation information is configured by optical means, the FG output signal does not change depending on the rotation speed, and high output voltage can be obtained even during low speed rotation, making it less susceptible to external noise. things can be provided.

- Since detection is performed by optical means, no external noise is generated, and no uneven rotation or vibration is generated.

■ The rotor position detection that performs electronic rectification is the light source.
It is composed of a second slit on a rotating plate and a second photoelectric conversion element on a planar photoelectric conversion element, and the slit shape of the second slit, the shape of the second photoelectric conversion element, or the shape of both can be changed. By doing this, an arbitrary detected waveform can be obtained. At the same time, since the planar photoelectric conversion element is formed by photoetching or the like, it is possible to increase the mechanical position accuracy, which improves the accuracy of rotor position detection and allows for high-precision electronic rectification. .

Then, a second photoelectric conversion element that detects the rotor position is
Since it is not on the stator coil board, the rotor position detection element does not interfere with the stator 1: coil arrangement in a motor that has a complicated coil arrangement and needs to be miniaturized.

[Brief explanation of drawings]

Figure 1 is a vertical sectional view of a motor equipped with a conventional rotation detection means, Figure 2 is a plan view of the rotor magnet of the same motor, and Figure 3
The figure is a plan view of the nuteta coil/V board and stator coil of the same motor, FIG. 4 is a cross-sectional perspective view of the main part of the motor, and FIG. 6 is a plan view of the rotating plate of the same motor, FIG. 7 is a plan view of the planar photoelectric conversion means of the same motor, FIG. 8 is a partially enlarged view of the rotating plate of the same motor, and FIG. 9 is a plan view of the rotating plate of the same motor. Figures 10a and 10b are explanatory diagrams of the operation of the first optical direct conversion means of the same motor, and Figures 11a, b, and c are views of the same motor. 12 is a circuit diagram of the detection circuit of the first photoelectric conversion means of the same motor, and FIG. 13 is a detection circuit of the second photoelectric conversion element of the same motor. Fig. 14 is a waveform diagram showing the operation of the second photoelectric conversion means of the same motor, Fig. 15 is a circuit diagram of &-+ b+ Or d
FIG. 1 is a perspective view and a plan view, respectively, showing one embodiment of a planar photoelectric conversion element of the present invention. FIG. 3 is a side view and an equivalent circuit diagram. 1...Rotation axis, 13...Light source, 14.
... Rotating plate, 15 ... Planar photoelectric conversion means, 17 ... First slit, 18 ...
- Second slit, 19...first photoelectric conversion means, 2o...second photoelectric conversion means. Name of agent: Patent attorney Toshio Nakao and 1 other person
4 Figure 8 Figure 9 eye p″KoCVtzr4p←Vkn) ?? Figure 13

Claims (1)

[Scope of Claims] 0) The electronic commutator is attached to the rotating shaft of the motor, and has a first slit of n number of slits (n is a positive integer) over the entire circumference, and has a radius different from that of the first slit. A rotary plate having second slits with a number of slits m (m is a positive integer) at positions in the direction, and a light source arranged at one end opposite to the surface of the rotary plate so as to irradiate all the slits with light. A planar photoelectric conversion means is arranged at the other end facing the rotary plate,
The planar photoelectric conversion means includes a first photoelectric conversion means provided over the entire circumference or substantially the entire circumference on the same member, and a second photoelectric conversion means provided at a different radial position from the first photoelectric conversion means. and a photoelectric conversion means for detecting rotational information of the electronic commutator motor by the output signal from the first photoelectric conversion means, and detecting rotation information of the electronic commutator motor by the output signal from the second photoelectric conversion means. An optical rotation detection device characterized in that it is configured to control the commutation action of a slave motor. (2) The first photoelectric conversion means is converted by two sets of photoelectric conversion means consisting of a plurality of photoelectric conversion element pieces separated in the radial direction over the entire circumference or substantially the entire circumference and electrodes that electrically couple these pieces. By rotating the rotary plate, two sets of signals having opposite phases are obtained from the two sets of photoelectric conversion means, respectively,
2. The optical rotation detection device according to claim 1, wherein rotation information of the electronic commutator motor is detected using a difference signal obtained by taking the difference between these two sets of signals. (3) As a planar photoelectric conversion element, a non-transparent electrode is placed on one surface of the amorphous silicon thin film forming the PiN junction.
Claim 1 is characterized in that an amorphous silicon nine-density conversion element is used, which has a sandwich structure with a transparent electrode formed on the other surface so that light from a light source is irradiated onto the transparent electrode. is the optical rotation detection device according to item 2. (4) The optical rotation detection device according to claim 1, wherein a light source having an emission wavelength of around 5,700 is used as a light source.