JP5614030B2 - Encoder and electromechanical device - Google Patents

Description

  The present invention relates to an encoder.

Et Nkoda, for example, is used to control the motor (for example, Patent Document 1). At this time, in order to control the motor at an extremely low rotation (0.1 to 100 [rpm]), it is preferable to increase the resolution of the encoder and increase the number of pulses to be generated.
In the future, DD motor drive will be easily realized with the advent of high-torque motors that do not use reduction gears. Therefore, since the rotation speed of the motor becomes the load rotation speed and becomes extremely low, high speed control is required electrically even at this extremely low speed, and resolution from the encoder is further required.

Japanese Patent Laid-Open No. 06-269147

  However, the conventional encoder has a problem that the slit pattern becomes complicated when trying to cope with high resolution. Further, there is a problem that the resolution is regulated by the width of the slit.

  An object of the present invention is to solve at least a part of the problems described above and to realize a high-resolution encoder with a simple configuration.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
According to one aspect of the invention, an encoder is provided. The encoder includes a rotating disk, an optical element composed of a light transmitting part or a reflecting plate provided at equal intervals on the rotating disk, a light emitting part for irradiating the optical element with light, and transmitting the optical element. A light receiving unit that receives or reflects reflected light and outputs an analog light reception signal having a magnitude corresponding to the received light intensity, and N predetermined analog light reception signals (N is an integer of 2 or more) And a pulse generator that generates a pulse signal having a period of 1 / N of the period of the analog light-receiving signal by using a threshold value of the optical element, and the optical element is arranged along a rotation direction of the optical element. The light transmittance or the light reflectance is configured to gradually increase or decrease, and the pulse generator is a two-phase pulse whose phase is shifted by π / 2 when the period of 1 / N is 2π. Generate a signal. According to the encoder of this embodiment, when the period of 1 / N of the period of the analog light reception signal is 2π, a two-phase pulse signal whose phase is shifted by π / 2 can be generated, and high resolution is achieved with a simple configuration. It becomes possible to realize a simple encoder.

[Application Example 1]
An encoder, comprising: a rotating disk; an optical element composed of a light transmitting part or a reflecting plate provided at equal intervals on the rotating disk; a light emitting part for irradiating the optical element with light; and the optical element. A light receiving unit that receives light that is transmitted or reflected and outputs an analog light reception signal having a magnitude corresponding to the magnitude of the light reception, and digitally converts the analog light reception signal after using a predetermined threshold value. And a pulse generator that generates pulse signals at regular intervals, and the optical element is configured such that light transmittance or light reflectance gradually increases or decreases along the rotation direction of the optical element. encoder.
According to this application example, since the light transmittance or light reflectance gradually increases and decreases along the rotation direction of the optical element, the analog light reception signal also gradually increases and decreases. Since this analog light reception signal is digitally converted using a predetermined threshold value to generate pulse signals at a constant interval, a high-resolution encoder can be realized with a simple configuration.

[Application Example 2]
In the encoder according to the application example 1, the optical element is a light transmitting portion, and includes a colored layer that reduces light transmittance, and the color density of the colored layer is gradually changed, so that the light An encoder that gradually increases or decreases its transparency.
According to this application example, it is possible to easily form a configuration in which the light transmittance or light reflectance gradually increases or decreases from both ends along the rotation direction of the optical element toward the center along the rotation direction of the optical element. It becomes.

[Application Example 3]
In the encoder according to application example 1, the optical element is a light transmission portion, and has a colored layer that reduces light transmittance and a transparent layer that maintains light transmittance in the light transmission direction, An encoder that gradually increases or decreases the light transmittance by changing the thickness of the colored layer in the light transmission direction and the thickness of the transparent layer in the light transmission direction.
According to this application example, it is possible to easily form a configuration in which the light transmittance or light reflectance gradually increases or decreases from both ends along the rotation direction of the optical element toward the center along the rotation direction of the optical element. It becomes.

[Application Example 4]
A control unit that controls an electric power supplied to the electromagnetic coil by using a magnet, an electromagnetic coil, the encoder according to any one of application examples 1 to 3, and an output of the encoder, the electromechanical device. And an electromechanical device.
According to this application example, it is possible to easily cope with extremely low rotation to high rotation.

[Application Example 5]
Although the present invention will be described using a rotary disk-like encoder, other linear encoders and curved encoders for linear motors can be realized in the same manner.

  The present invention can be realized in various forms. For example, the present invention can be realized in various forms such as an electromechanical apparatus in addition to an encoder.

It is explanatory drawing which shows typically the structure of the motor system which concerns on a 1st Example. It is explanatory drawing which shows an example of the control block of a motor system. It is explanatory drawing which shows the structure of an encoder. It is explanatory drawing which expands and shows the light emission part light-receiving part vicinity. It is explanatory drawing which shows each signal. It is explanatory drawing which shows the case where the light received signal A0B0 becomes a triangular wave. It is explanatory drawing which shows an example of a structure of the 1st, 2nd light transmissive part. It is explanatory drawing which shows an example of a rotation direction signal generation part. It is a timing chart in a rotation direction signal generation part. It is explanatory drawing which shows a 2nd Example. It is explanatory drawing which shows each signal in a 2nd Example. It is explanatory drawing which shows the projector using the motor by the modification of this invention. It is explanatory drawing which shows the fuel cell type mobile telephone using the motor by the modification of this invention. It is explanatory drawing which shows the electric bicycle (electric assisted bicycle) as an example of the moving body using the motor / generator by the modification of this invention. It is explanatory drawing which shows an example of the robot using the motor by the modification of this invention. It is explanatory drawing which shows the rail vehicle using the motor by the modification of this invention.

[First embodiment]
FIG. 1 is an explanatory diagram schematically showing the configuration of the motor system according to the first embodiment. The motor system includes a motor 100, an encoder 300, and a load 400. The motor 100 includes a drive shaft 110, a magnet 120, an electromagnetic coil 130, and a magnetic sensor 140. There is no particular limitation on the configuration of the magnet that generates the rotational force of the motor 100 and the configuration of the electromagnetic coil, and various configurations can be used. The drive shaft 110 is connected to a rotor (not shown) provided with a magnet 120. The magnetic sensor 140 is used to detect the relative position (phase) of the magnet 120 with respect to the electromagnetic coil 130, and for example, a Hall IC can be used. However, the magnetic sensor 140 can be omitted.

  FIG. 2 is an explanatory diagram illustrating an example of a control block of the motor system. The control unit 500 of the motor 100 includes a CPU 505, a drive control circuit unit 510, a PWM control unit 520, a drive unit 530, a current detection unit 535, and a measurement unit 540. The measurement unit 540 determines the maximum current value based on the detection current signal Imes output from the current detection unit 535, the magnetic sensor signal Smag output from the magnetic sensor 140, and the synthesized pulse signal Senc output from the encoder 300. This is an arithmetic circuit that calculates Imax, average current value Iave, and motor rotation speed Nmes. The drive control circuit unit 510 and the PWM control unit 520 execute control of the motor 100 (electric servo motor 100) based on the maximum current value Imax and / or the average current value Iave and the motor rotation speed Nmes. Specifically, the drive control circuit unit 510 determines an adjustment value for adjusting the pulse width in the PWM control based on the maximum current value Imax and / or the average current value Iave and the motor rotation speed Nmes, and sets the adjustment value to this adjustment value. Based on this, the PWM control unit 520 generates a PWM control signal. The drive unit 530 includes an H bridge circuit (not shown) configured by a plurality of switching elements. Driving voltage is supplied from the driving unit 530 to the electromagnetic coil of the motor 100 by turning on and off the switching elements of the bridge circuit. The current detection unit 535 is a current sensor that measures a current flowing through the driving unit 530 (that is, a current flowing through the coil 130 of the motor 100).

  FIG. 3 is an explanatory diagram showing the configuration of the encoder. FIG. 3A shows the rotating disk of the encoder 300. The rotating disk 310 includes a first light transmission part 312 and a second light transmission part 314. The first light transmission unit 312 and the second light transmission unit 314 are each m (m is an integer of 2 or more), and the first light transmission unit 312 and the second light transmission unit 314 are the rotating disk 310. Are alternately arranged at equiangular intervals with respect to the center O of the. That is, the parallax when the center O of the rotating disk 310 is viewed from both ends in the rotational direction of the first light transmitting portion 312 is 2π / 2 m. The configuration of the second light transmission unit 314 is the same. In the present specification, an angle measured on the rotating disk 310 is referred to as a “mechanical angle”.

  FIG. 3B is a side view of the encoder 300. In the encoder 300, a light emitting unit 320 and a light receiving unit 370 are disposed so as to sandwich the rotating disk 310.

  FIG. 4 is an explanatory diagram showing an enlarged view of the vicinity of the light emitting unit and the light receiving unit. The encoder 300 includes a light shielding unit 315 and a signal forming unit 380 in addition to the rotating disk 310, the light emitting unit 320, and the light receiving unit 370. The light shielding plate 315 is disposed between the rotating disk 310 and the light emitting unit 320. The light shielding unit 315 includes two lenses 317. The lens 317 collects the light from the light emitting unit 320 and irradiates the first light transmitting unit 312 and the second light transmitting unit 314. In addition, the structure provided with a slit instead of a lens may be sufficient. Here, the alternate long and short dash line 317 a shown in the figure indicates the central axis of the lens 317. The distance between the centers of the two lenses 317 is longer than that of the first light transmission unit 312 and the second light transmission unit 314. When the lengths of the first light transmitting portion 312 and the second light transmitting portion 314 are 4π, the distance between the centers of the two lenses 317 is preferably (4π × n + π / 4, where n is an integer). .

  The first light transmission unit 312 has different light transmittance depending on the location. For example, in this embodiment, the light transmittance is small at both ends (front end side and rear end side) of the rotating disk 310 in the rotation direction, and the light transmittance is large at the center. The same applies to the second light transmission portion 314.

  The light receiving unit 370 includes a first light receiving element 372 and a second light receiving element 374. The centers of the first light receiving element 372 and the second light receiving element 374 are located on the central axis 317 a of the lens 317. For example, a photodiode, a phototransistor, a CCD sensor, or a CMOS sensor can be used as the first and second light receiving elements 372 and 374. The signal forming unit 380 includes first and second comparators 382 and 384 and first and second logic circuits 386 and 388. Here, the first comparator 382 and the first logic circuit 386 include the first and second logic circuits 386 and 388, respectively. The second comparator 384 and the second logic circuit 388 correspond to the second light receiving element 374. The first logic circuit 386 includes an inverter circuit 386a and an AND circuit 386b. The same applies to the second logic circuit 388.

  The light emitted from the light emitting unit 320 is condensed through the lens 317 and becomes thin light. The condensed light passes through the first light transmission unit 312. Here, when the rotary disk 310 rotates in the direction of the arrow shown in the drawing (from the left to the right in the drawing), the first light transmitting portion 312 also moves in the direction of the arrow. The position at which the collected light passes through the first light transmitting portion 312 is initially on the right side of the first light transmitting portion 312, but as the rotating disk 310 rotates, it becomes the center and leftward. Move. As described above, the first light transmission portion 312 has a small light transmittance at both ends (front end side and rear end side) in the rotation direction, and a large light transmittance at the center portion. The light transmitted through the portion 312 increases gradually and then decreases gradually.

When the first light receiving element 372 receives light transmitted through the first light transmitting portion 312, the first light receiving element 372 outputs a light reception signal A0 depending on the amount (size) of the received light. As described above, the light transmitted through the first light transmission unit 312 gradually increases and then gradually decreases. Therefore, the light reception signal A0 is a so-called mountain-shaped analog signal that gradually increases and then decreases. Each time light passes through the first light transmitting portion 312, a peak is periodically generated in the light reception signal A0. The first comparator 382 performs analog-digital conversion (AD conversion) on the light reception signal A0 and outputs two pulse signals A1 and A2. The first logic circuit 386 generates the first pulse signal S1 using the two pulse signals A1 and A2. Note that the light transmitted through the second light transmission unit 314 is similarly processed to generate the first pulse signal S1. The first and second light transmission units 312 and 314 may have the same configuration. The second light receiving element 374, the second comparator 384, and the second logic circuit 388 generate a light receiving signal B0, two pulse signals B1, B2, and a second pulse signal S2, respectively. The first pulse signal S1 or the second pulse signal S2 can be used as the combined pulse signal Senc shown in FIG.

FIG. 5 is an explanatory diagram showing each signal. The received light signals A0 and B0 have a mountain shape that gradually increases and then decreases gradually. If this period is 4π, the periods of the received light signals A0 and B0 are shifted by π / 2 . The reason why the period of the light reception signals A0 and B0 is 4π is that the period of the pulse signals S1 and S2 is 2π.

The first comparator 382 (FIG. 4) generates pulse signals A1 and A2 from the light reception signal A0 using the two threshold values V1 and V2. When the magnitude of the light reception signal A0 is larger than the first threshold value V1, the pulse signal A1 is H. When the magnitude of the light reception signal A0 is smaller than the first threshold value V1, the pulse signal A1 is L. It becomes. The second threshold value V2 is smaller than the first threshold value V1. When the magnitude of the light reception signal A0 is larger than the second threshold value V2, the pulse signal A2 is H. When the magnitude of the light reception signal A0 is smaller than the second threshold value V2, the pulse signal A2 is L. It becomes. As shown in FIG. 5, the pulse signal A1 has a short H period, and the pulse signal A2 has a long H period.

The inverter circuit 386a of the first logic circuit 386 inverts the pulse signal A1 to generate the pulse signal / A1. The AND circuit 386b takes an AND of the pulse signal / A1 and the pulse signal A2, and generates a pulse signal S1. The pulse signal S1 preferably has the same length during the H period and the L period. For this purpose, the ratio of the H period to the L period is preferably 1: 3 for the pulse signal A1, and the ratio of the H period to the L period is preferably 3: 1 for the pulse signal A2. The threshold values V1 and V2 are preferably determined so that the ratio between the H period and the L period is such a ratio. The threshold values V1 and V2 can be easily obtained by experiments. Since the signals B0 to B2 and S2 are the same, description thereof is omitted.

  FIG. 6 is an explanatory diagram showing a case where the light reception signals A0 and B0 are triangular waves. If the received light signals A0 and B0 are triangular waves, the two threshold values V1 and V2 can be easily set by proportional distribution. For this purpose, it is preferable to configure the first and second light transmission units 312 and 314 so that the transmittance is directly proportional to the light transmission position.

  FIG. 7 is an explanatory diagram showing an example of the configuration of the first and second light transmission parts. In the example shown in FIG. 7A, the rotating disk 310 includes a transparent substrate 311 and a colored layer 311a. The colored layer 311a is applied in units of the first light transmission part 312 and is dark at both ends of the first light transmission part 312 (low light transmission) and thin at the center (light transmission is low). It is colored with a gradation so that it becomes higher. The same applies to the second light transmission portion 314. In this case, since the colored layer 311a is only colored with gradation, it is possible to easily change the transmittance of the first light transmitting portion 312 depending on the location.

  In the example shown in FIG. 7B, the rotating disk 310 includes a transparent layer 312a and a colored layer 312b. The thicknesses of the transparent layer 312a and the colored layer 312b in the direction in which light travels (arrows in the drawing) differ depending on the location. That is, the transparent layer 312a is thin and the colored layer 312b is thick at both ends of the first light transmission portion 312. On the other hand, the transparent layer 312a is thick and the colored layer 312b is thin at the center of the first light transmitting portion 312. Thereby, it is possible to easily change the transmittance of the first light transmitting portion 312 depending on the location. Note that since the light transmittance of the colored layer 312b is determined by the light transmission length, it is not necessary to form a gradation in the colored layer 312b.

  The example shown in FIG. 7C is the same as the example shown in FIG. In the example shown in FIG. 7B, the interface between the transparent layer 312a and the colored layer 312b is a plane, whereas the example shown in FIG. 7C is a curved surface.

  The example shown in FIG. 7D is an example including a reflecting plate instead of the light transmitting portion. In this example, the light emitting unit 320 and the light receiving unit 370 are arranged on the same side with respect to the rotating disk 310. A reflector 318 and a colored layer 319 are provided on the light emitting unit 320 and the light receiving unit 370 side of the rotating disk 310. The reflector 318 reflects the light from the light emitting unit 320. The colored layer 319 is colored so that the light transmittance is periodically different, similarly to the colored layer 311a shown in FIG.

  FIG. 8 is an explanatory diagram illustrating an example of the rotation direction signal generation unit. The rotation direction signal generation unit 390 includes latch circuits 391 and 392. As the latch circuits 391 and 392, for example, a D-flip flop circuit can be used. The latch circuits 391 and 392 include an input terminal D, a clock terminal C, and an output terminal Q. The signal input to the input terminal D is latched at the rising edge of the signal input to the clock terminal C and is output to the output terminal Q. In this embodiment, the light reception signal S1 is input to the input terminal D of the latch circuit 391, the light reception signal S2 is input to the clock terminal C, and the rotation direction signal Q1 is output from the output terminal Q. The light reception signal S2 is input to the input terminal D of the latch circuit 392, the light reception signal S1 is input to the clock terminal C, and the rotation direction signal Q2 is output from the output terminal Q.

  FIG. 9 is a timing chart in the rotation direction signal generation unit. FIG. 9A is a timing chart during normal rotation. In the period from the start to the rise of the light reception signal S2, the rotation direction signal Q1 is indefinite. The latch circuit 391 latches the light reception signal S1 at the rising edge of the light reception signal S2, and outputs the rotation direction signal Q1. In this embodiment, since the light reception signal S1 is H when the light reception signal S2 rises, the rotation direction signal Q1 is H. On the other hand, the rotation direction signal Q2 is indefinite during the period from the start to the rise of the light reception signal S1. The latch circuit 392 latches the light reception signal S2 at the rising edge of the light reception signal S1, and outputs a rotation direction signal Q2. In this embodiment, since the light reception signal S2 is L when the light reception signal S1 rises, the rotation direction signal Q2 is L. FIG. 9B is a timing chart during reverse rotation. During reverse rotation, the order of the light reception signals S1 and S2 is reversed from that during forward rotation. As can be seen from the rotation direction signals Q1 and Q2, in the case shown in FIG. 9B, it can be seen that the encoder 300 is rotating in reverse.

As described above, according to the first embodiment, the light reception signal A0 (analog signal) that has passed through the light transmission units 312 and 314 is AD-converted with the two threshold values to generate the pulse signal S1. Therefore, it is not necessary to provide a plurality of fine slits on the rotating disk 310, and the number of light receiving elements may be one for the pulse signal S1. That is, it is possible to realize a high-resolution encoder with a simple configuration.

  It is very easy to receive light by changing the light transmittance by changing the density of the colored layer 311a, or changing the light transmittance by changing the thickness of the transparent layer 312a and the colored layer 312b in the light transmission direction. The signal A0 can be an analog signal. Even when the light is reflected by the reflecting plate 318, the light reception signal A0 can be converted into an analog signal very easily because only the intensity of the reflected light is changed by changing the density of the colored layer 319.

[Second Embodiment]
FIG. 10 is an explanatory diagram showing the second embodiment. The third embodiment is different in that the first comparator 382 has four threshold values and generates four pulse signals A1 to A4. The first logic circuit 386 includes an inverter circuit 386a, an AND circuit 386b, and an OR circuit 386c, and generates a first pulse signal S1 from the four pulse signals A1 to A4. The same applies to the second comparator 384 and the second logic circuit 386.

FIG. 11 is an explanatory diagram showing signals in the second embodiment. In the same manner as shown in the first embodiment, pulse signals A1 to A4 are generated using threshold values V1 to V4. At this time, the ratio of the H period to the L period is 1: 7 for the pulse signal A1, the ratio of the H period to the L period is 3: 5 for the pulse signal A2, and the ratio of H is about the pulse signal A3. The ratio of the period to the L period is preferably 5: 3, and the ratio of the H period to the L period for the pulse signal A4 is preferably 7: 1. In this way, the pulse signal S1 can have the same length during the H period and the L period. Therefore, it is preferable to determine the values of the threshold values V1 to V4 so as to be like this. That is, it can be configured without using a component having a large resolution by S * N due to the relationship between the number S of light transmitting portions 312, 314 and the threshold number N. Regarding the configuration of the logic circuit 386, various circuit configurations can be employed in accordance with the number of pulse signals. The same applies to the signals B0 to B4 and S2.

  As described above in the second embodiment, by providing a large number of threshold values, the cycle of the pulse signal S1 can be shortened and the resolution of the encoder 300 can be further improved.

  In each of the above-described embodiments, the first and second light transmitting portions 312, 314 have the light transmittance at the ends reduced and the light transmittance at the center increased, but conversely the light transmittance at the ends is increased. The light transmittance at the center may be reduced. It is also possible to employ an encoder that can be operated without setting an initial condition even when the power is turned on, such as an absolute encoder, using an E2-PROM.

  In the above description, the rotary disk-shaped encoder 300 has been described as an example. However, the present invention can be similarly applied to a linear encoder or a curved encoder for a linear motor.

Application example:
The present invention is applicable to various devices. For example, the present invention can be applied to motors of various devices such as a fan motor, a clock (hand drive), a drum type washing machine (single rotation), a roller coaster, and a vibration motor. When the present invention is applied to a fan motor, for example, various effects (low power consumption, low vibration, low noise, low rotation unevenness, low heat generation, long life) can be achieved. Such fan motors include, for example, digital display devices, in-vehicle devices, fuel cell computers, fuel cell digital cameras, fuel cell video cameras, fuel cell devices such as fuel cell phones, projectors, and other various types. Can be used as a fan motor for equipment. The motor of the present invention can also be used as a motor for various home appliances and electronic devices. For example, the motor according to the present invention can be used as a spindle motor in an optical storage device, a magnetic storage device, a polygon mirror driving device, or the like. The motor according to the present invention can also be used as a motor for a moving body or a robot.

  FIG. 12 is an explanatory diagram showing a projector using a motor according to a modification of the present invention. The projector 3100 includes three light sources 3110R, 3110G, and 3110B that emit red, green, and blue color lights, and three liquid crystal light valves 3140R, 3140G, and 3140B that modulate these three color lights, respectively. A cross dichroic prism 3150 that synthesizes the modulated three-color light, a projection lens system 3160 that projects the synthesized three-color light onto the screen SC, a cooling fan 3170 for cooling the inside of the projector, and a projector 3100 And a control unit 3180 for controlling the whole. As the motor for driving the cooling fan 3170, the various brushless motors described above can be used.

  FIG. 13 is an explanatory view showing a fuel cell type mobile phone using a motor according to a modification of the present invention. FIG. 13A shows the appearance of the mobile phone 3200, and FIG. 13B shows an example of the internal configuration. The mobile phone 3200 includes an MPU 3210 that controls the operation of the mobile phone 3200, a fan 3220, and a fuel cell 3230. The fuel cell 3230 supplies power to the MPU 3210 and the fan 3220. The fan 3220 is used to blow air from the outside of the mobile phone 3200 to supply air to the fuel cell 3230 or to discharge moisture generated by the fuel cell 3230 from the inside of the mobile phone 3200 to the outside. It is. Note that the fan 3220 may be disposed on the MPU 3210 as shown in FIG. 13C to cool the MPU 3210. As the motor for driving the fan 3220, the various brushless motors described above can be used.

  FIG. 14 is an explanatory diagram showing an electric bicycle (electrically assisted bicycle) as an example of a moving body using a motor / generator according to a modification of the present invention. In this bicycle 3300, a motor 3310 is provided on the front wheel, and a control circuit 3320 and a rechargeable battery 3330 are provided on a frame below the saddle. The motor 3310 assists traveling by driving the front wheels using the electric power from the rechargeable battery 3330. Further, the electric power regenerated by the motor 3310 is charged in the rechargeable battery 3330 during braking. The control circuit 3320 is a circuit that controls driving and regeneration of the motor. As the motor 3310, the above-described various brushless motors can be used.

  FIG. 15 is an explanatory diagram showing an example of a robot using a motor according to a modification of the present invention. The robot 3400 includes first and second arms 3410 and 3420 and a motor 3430. This motor 3430 is used when horizontally rotating the second arm 3420 as a driven member. As the motor 3430, the above-described various brushless motors can be used.

  FIG. 16 is an explanatory view showing a railway vehicle using a motor according to a modification of the present invention. The railway vehicle 3500 has a motor 3510 and wheels 3520. The motor 3510 drives the wheel 3520. Further, the motor 3510 is used as a generator during braking of the railway vehicle 3500 to regenerate electric power. As the motor 3510, the above-described various brushless motors can be used.

  The embodiments of the present invention have been described above based on some examples. However, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

DESCRIPTION OF SYMBOLS 100 ... Motor 110 ... Drive shaft 120 ... Magnet 130 ... Coil (electromagnetic coil)
DESCRIPTION OF SYMBOLS 140 ... Magnetic sensor 300 ... Encoder 310 ... Rotating disk 311 ... Transparent substrate 311a ... Colored layer 312, 314 ... Light transmission part 312a ... Transparent layer 312b ... Colored layer 315 ... Light shielding part 317 ... Lens 318 ... Reflecting plate 319 ... Colored layer 320 ... Light emitting unit 370 ... Light receiving unit 372, 374, 376, 378 ... Light receiving element 380 ... Signal forming unit 380a ... First phase signal forming unit 380b ... Second phase signal forming unit 382, 384 ... Comparator 386, 388 ... Logic circuit 386a ... Inverter circuit 390 ... Rotation direction signal generation unit 391 ... Latch circuit 392 ... Latch circuit 400 ... Load 500 ... Control unit 510 ... Drive control circuit unit 530 ... Drive unit 535 ... Current detection unit 540 ... Measurement unit 3100 ... Projector 3110R ... Light source 3140R ... Liquid crystal light valve DESCRIPTION OF SYMBOLS 150 ... Cross dichroic prism 3160 ... Projection lens system 3170 ... Cooling fan 3180 ... Control part 3200 ... Cell-phone 3220 ... Fan 3230 ... Fuel cell 3300 ... Bicycle 3310 ... Motor 3320 ... Control circuit 3330 ... Rechargeable battery 3400 ... Robot 3410 ... Second Arm 3420 ... Second arm 3430 ... Motor 3500 ... Railway vehicle 3510 ... Motor 3520 ... Wheel

Claims (4)

An encoder,
A rotating disk,
An optical element composed of a light transmission part or a reflection plate provided at equal intervals on the rotating disk;
A light emitting unit for irradiating the optical element with light;
A light receiving unit that receives light that is transmitted through or reflected by the optical element and outputs an analog light reception signal having a magnitude corresponding to the magnitude of the received light;
A pulse generation unit that digitally converts the analog light reception signal using predetermined N thresholds (N is an integer of 2 or more) to generate a pulse signal having a period of 1 / N of the period of the analog light reception signal; ,
With
The optical element is configured such that light transmittance or light reflectance gradually increases or decreases along the rotation direction of the optical element ,
The pulse generator is an encoder that generates a two-phase pulse signal whose phase is shifted by π / 2 when the 1 / N cycle is 2π . The encoder according to claim 1,
The optical element is a light transmission part, and has a colored layer that reduces the light transmittance. By gradually changing the color density of the colored layer, the light transmittance is gradually increased or gradually increased. Decreasing the encoder. The encoder according to claim 1,
The optical element is a light transmission part, and in the light transmission direction,
A colored layer that reduces light transmission;
A transparent layer that maintains light transmission;
Have
An encoder that gradually increases or decreases the light transmittance by changing the thickness of the colored layer in the light transmission direction and the thickness of the transparent layer in the light transmission direction. An electromechanical device,
A magnet,
An electromagnetic coil;
The encoder according to any one of claims 1 to 3,
A control unit for controlling electric power supplied to the electromagnetic coil using an output of the encoder;
An electromechanical device comprising:

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