JP3465483B2 - Encoder device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoder device that can be used for detecting the position of a driven body, and more particularly to an incremental encoder device that can detect a specific position such as a reference position.

[0002]

2. Description of the Related Art An encoder device is used for position detection, speed detection, position control, speed control, etc. of a driven body when the driven body is moved using a linear motor, a rotary motor or the like. . For example, an optical encoder device is usually provided with an encoder scale having a chart portion in which low-reflectance surfaces and high-reflectance surfaces are alternately arranged, and is arranged so as to face the encoder chart. The magnitude of the intensity, etc.) can be detected. In this case, the detection element includes, for example, a light emitting element and a light receiving element, and the light emitted from the light emitting element and reflected by the high reflectance surface or the low reflectance surface is detected by the light receiving element and is received by the light receiving element. The light is bright or dark. As a result, when the encoder scale and the detection element move relative to each other, the detection element alternately moves each of the low-reflectance surface and the high-reflectance surface to detect the light-dark signal of the light and the dark-light signal. It is possible to output a pulsed signal based on the signal.

When an encoder system of the incremental type is constructed by the encoder system as described above, the relative position can be detected on the basis of the pulse-like signal, but the absolute position cannot be determined, so that in the encoder system of the incremental system. The encoder scale is usually provided with a reference position mark (origin mark) outside the chart, and a detection element different from the detection element for the chart is arranged with respect to the reference mark. The reference mark is a so-called Z phase and is provided at one specific position on the scale. Therefore, the reference mark detection element outputs a pulse only at one specific location due to the relative movement of the scale and the detection element.

Further, instead of providing the Z phase on the scale,
A sensor or the like may be arranged on the driven body itself to detect the reference position (origin position). For example, the photo interrupter is fixedly arranged on the driven body and the photo sensor is fixedly arranged at the reference position, and the driven body is moved so that the photo interrupter of the driven body shields the light from the photo sensor at the reference position. It can be detected that it is at the reference position.

[0005]

However, in the encoder device provided with the Z phase, it is necessary to provide a detection element for detecting the Z phase separately from the chart detection element. Further, since the Z phase indicates a reference position for pulse counting, and because it is used for clearing the count pulse, etc., it can usually be provided only at one point on the scale. The width of the phase is usually fixed to 1/4 of the pitch of the chart in order to obtain accuracy in the positional relationship between the reference position and the chart.

Further, when the reference position is detected by the method of disposing a sensor or the like on the driven body itself, it is difficult to accurately align the position of the sensor and the encoder chart. In addition, since the sensor must be provided separately from the encoder device and has a mechanical structure, it may be damaged due to collision due to movement, and since the sensor itself has a large variation in reaction, highly accurate reference position detection is possible. difficult.

Therefore, the present invention is an incremental type encoder device, which does not require a dedicated detection element for detecting a specific position such as a reference position separately from the detection element for detecting an encoder chart, and can accurately perform the same. It is an object to provide an encoder device that can detect a specific position such as a reference position.

[0008]

In order to solve the above-mentioned problems, the present invention provides the following encoder device. An optical encoder scale having an optical encoder chart of standard pitch P formed by alternately arranging a low-reflectance surface having a width P / 2 and a high-reflectance surface having a width P / 2 in a predetermined direction, and the chart. And a light detection means having first and second detection elements that are arranged to face each other and capable of detecting light and darkness of light, and perform a logical operation of each detection signal of the two detection elements of the light detection means. And a width of at least one of the low light reflectance surface and the high light reflectance surface of the encoder chart is α · P / 2.
(Α is a positive real number other than 1), and is the first of the detection means.
And the second detection element is n · P + P / 2 in the predetermined direction.
(N is an integer equal to or greater than 0), and the logical operation means performs a logical operation to output that fact when the detection signals of the two detection elements are the same when the detection signals of the two detection elements are the same. Optical encoder device.

The above-mentioned optical encoder device can form a so-called reflection type or transmission type optical encoder device. That is, in the case of a reflection type optical encoder device, the low light reflectance surface and the high light reflectance surface in the encoder chart are typically formed on the encoder scale surface. The low reflectance surface is painted black and the high light reflectance surface is painted white. In this case, the first and second detecting elements of the light detecting means are, for example, sensors each including a light emitting element and a light receiving element, and these are arranged on one side of the scale. At this time, the light emitted from the light emitting element is reflected by the low light reflectance surface or the high light reflectance surface and is received by the light receiving element. The light received by the light receiving element is dark when it is reflected by the low light reflectance surface (small brightness, low light intensity, etc.), and bright when it is reflected by the high light reflectance surface (high brightness, The light intensity is high).

Further, in the case of a transmissive encoder device, typically, the low light reflectance surface and the high light reflectance surface in the encoder chart can be formed by a slit provided in the encoder scale. The surface is the slit portion of the scale, and the high-reflectance surface is the slit portion of the scale. Also in this case, the first and second detection elements of the light detection means may be, for example, sensors each including a light emitting element and a light receiving element, and the light emitting element and the light receiving element may be the scale. The scale is placed on both sides of the scale. At this time, the light emitted from the light emitting element, the light low reflectance surface, that is, the light is received by the light receiving element through the slit, high light reflectance surface,
That is, the light is reflected by the portion without the slit and does not reach the light receiving element. Therefore, the light received by the light receiving element is bright (high brightness, high light intensity, etc.) when facing the low light reflectance surface, and light when facing the high light reflectance surface. It becomes dark (low brightness, low light intensity, etc.).

In either the reflection type or the transmission type, the light detecting means can detect the brightness of light. For the low light reflectance surface and the high light reflectance surface in the optical encoder chart, for example, only one position of the width of the high light reflectance surface has a standard width P /
When α · P / 2 different from 2 (α is a positive real number other than 1; the same applies hereinafter), the respective surfaces are arranged as follows in the vicinity of the different widths. That is, a low light reflectance surface having a width P / 2, a high light reflectance surface having a width P / 2, a light low reflectance surface having a width P / 2, a light high reflectance surface having a width α · P / 2, and a width P. A low light reflectance surface of / 2, a high light reflectance surface of a width P / 2, and so on.

The above description also applies to the optical encoder device described later. As described above, the first and second detecting elements of the light detecting means, which are arranged to face the encoder chart in which the low-reflectance surface and the high-reflectance surface are arranged, are n-directional in the predetermined direction as described above.・ P + P / 2
(N is an integer greater than or equal to 0) Since the positions are shifted, the width is α
There is a case where both the first and second detection elements are located on the same reflectance surface in the vicinity of the P / 2 surface (one surface of the low light reflectance surface and the high light reflectance surface).

For example, when only one part of the width of the high-reflectance surface is α · P / 2, when α is larger than 1 (α>
In 1), when both the first and second detection elements face the light high reflectance surface and α is smaller than 1 (α <
In 1), there is a position where both the first and second detection elements face the low light reflectance surface. At other positions, the first and second detection elements face the surfaces having different light reflectances.

Therefore, according to the above optical encoder device, when the encoder scale and the light detecting means move relative to each other, the low-reflectance surface with the width P / 2 and the high-reflectance surface with the width P / 2 are reflected. When the light detecting means relatively moves to a position facing the chart portion of the standard pitch P composed of the rate surface, the light or dark detection signal of the light detected by the first or (and) the second detecting element as in the conventional case. Can be used for position detection, speed detection, position control, speed control, and the like.

Further, when the first and second detection elements relatively move near the position facing the surface of the width α · P / 2, both the first and second detection elements have the same light reflectance. There is a case where the detection signal of each detection element becomes a "bright" signal (or a "dark" signal) when it is located at a position facing the surface, and when it is at that position, the logical operation means, for example, an exclusive OR. When a negative (EXCLUSIVE-NOR) operation is performed, an operation result that is different from other positions only in this position is obtained.
For example, when in this position, the detection signals of the first and second detection elements are both “bright” signals (this is referred to as “Hi” signal,
When it is a “1” signal), a negative (EX-NOR) operation of these exclusive ORs results in a “Hi” signal (“1” signal). Since the output signals are different from each other, if an exclusive OR (EX-NOR) operation of these signals is performed, "L
The position where the "o" signal ("0" signal) is generated and the "Hi" signal is output from the logical operation means can be used as a predetermined specific position such as a reference position. In this example, the same result can be obtained by performing a logical product (AND) operation.

The logical operation performed by the logical operation means is the negation of the exclusive OR (EXCLUSIVE--
In addition to the NOR operation, exclusive OR (EXCLUSI)
Even with a VE-OR) operation, the output result will be inverted,
A specific position such as a reference position can be detected. Also,
When the logics of the signals output from the respective detection elements when both the first and second detection elements are at the positions facing the same reflectance surface are "Hi", the logical operation means calculates the logical product (AND). Or a logical product NOT (NAND) operation can be performed to detect a specific position, and when the logics of the respective output signals are both "Lo", the logical operation means performs a logical sum (OR) or a logical NOT. The specific position can be detected even if the (NOR) calculation is performed.

The surface having the width α · P / 2 may be provided not only at one place on the scale but also at two or more places depending on the specific position to be detected. Further, when two or more places are provided, a means for distinguishing them may be provided if necessary. In the optical encoder device described above, in the light detection means,
A third detection element, which is arranged so as to face the chart and is capable of detecting light and darkness of light, is provided, and the third detection element is arranged in the predetermined direction by m · P in the predetermined direction.
The positions may be shifted by + P / 4 (m is an integer of 0 or more).

In this case, a so-called two-phase encoder device having a pitch of P / 4 and a phase angle of 90 degrees is formed by the first and third detecting elements or the second and third detecting elements. be able to. Next, a second encoder device according to the present invention is shown below. The optical encoder device is capable of detecting the position of a driven body which is driven by a drive unit and moves in a predetermined direction. The optical encoder device has a low light reflectance surface of width P / 2 and a high light reflectance surface of width P / 2. An optical encoder scale having an optical encoder chart of standard pitch P formed alternately in the predetermined direction, and light having a first detection element that is arranged so as to face the chart and is capable of detecting light and darkness of light. Detecting means, encoder operation detecting means capable of detecting the change state of the detection signal of the light detecting means, drive operation detecting means capable of detecting the operation status of the driving means, encoder operation detecting means and drive operation detecting A logical operation means capable of performing a logical operation of each detection signal of the means, one of the encoder scale or the light detection means is fixedly arranged, the other is The width of the low-reflectance surface or the high-reflectance surface of at least one position of the encoder chart is β · P / 2 (β is larger than 1). Real number), and the logical operation means determines that the detection signal of the encoder operation detection means is the same as the detection signal of the drive operation detection means even though the detection signal of the drive operation detection means is a signal indicating that the drive means is operating. An optical encoder device that performs a logical operation to output a signal indicating that the detection signal of the light detection means is unchanged.

In the optical encoder device described above, either a reflection type or a transmission type optical encoder device can be constructed, like the optical encoder device described above. Since the width of at least one of the low light reflectance surface or the high light reflectance surface is β · P / 2 (β is a real number larger than 1, the same applies hereinafter), the chart in this encoder device has other widths. P / 2 light low reflectance surface and width P
It is formed wider than the high light reflectance surface of / 2.

The encoder operation detecting means can detect whether or not the signal output by the detecting element of the light detecting means is changing. For example, it is possible to detect how many pulses the pulse signal output from the detection element is in a predetermined time. Therefore, the encoder operation detecting means opposes when the encoder scale and the light detecting means do not move relative to each other, and faces the wide β · P / 2 light high reflectance surface or low light reflectance surface. It is detected that there is no change in the output signal of the detection element when the photodetection means moves relatively to the position.

The driving operation detecting means can detect whether or not the driving means is driving the driven body. The drive means here is a motor having an armature coil, and the drive operation detection means includes a current sensor capable of detecting the current flowing through the armature coil of the motor.
The drive operation detecting means may further include means capable of detecting the presence or absence of a detection signal of the current sensor, that is, a means capable of detecting whether or not a current is flowing in the armature coil.

According to the above encoder device, a predetermined specific position such as a reference position can be detected as follows. One of the encoder scale and the light detection means is fixedly arranged, and the other is arranged on the driven body, so that as the driven body is driven in the predetermined direction by the driving means, Both move relatively.

In this way, when the two are relatively moved, the chart portion of the standard pitch P consisting of the light low reflectance surface of the width P / 2 and the light high reflectance surface of the width P / 2 is displayed. When the light detection means moves relatively to the facing position,
The light / dark detection signal of the light detected by the first detection element can be used for position detection, speed detection, position control, speed control, and the like as in the conventional case.

Further, when the detection element moves relatively to the position facing the wide β · P / 2 surface, the encoder operation detection means means that the output signal of the detection element does not change. On the other hand, the driving operation detecting means outputs a signal meaning that the driven body is being driven, and the logical operation result of both signals performed by the logical operation means is a wide β · P / 2. Since the output result of the logical operation means is different when the position other than the plane is relatively moved, the wide β
-The surface position of P / 2 can be specified. The position can be used as a specific position such as a reference position (origin position). This means that the encoder operation detecting means detects that there is no change in the output signal of the detecting element even though the driving means is driving the driven body. It is based on the fact that there is nothing other than the surface position.

For example, the output of the encoder operation detecting means outputs a "Lo" signal when there is no change in the output signal of the detecting element, and the "Hi" signal is output when there is a change, and the drive operation detecting means outputs a driven signal. "Hi" when driving the body
When the signal is not driven, when outputting the “Lo” signal, the logical operation means, for example, the exclusive OR (EX
CLUSIVE-OR), the result is
If the drive operation detecting means outputs "Hi", the "Hi" signal is output at the wide β · P / 2 surface position, and the "Lo" signal is output at other positions.

Like the encoder device described above, the encoder device described above can also constitute a so-called two-phase encoder device. In this case, the light detection means,
A second detection element, which is arranged so as to face the chart and is capable of detecting light and darkness of light, is provided, and the second detection element is m · P + P / 4 (m in the predetermined direction) with the first detection element.
Is an integer of 0 or more).

The present invention provides not only the optical encoder device described above, but also a magnetic encoder device to solve the above problems. The magnetic encoder device is the optical encoder device described above, wherein the high light reflectance surface is an N pole (S pole) and the low light reflectance surface is an S pole (N pole).
Then, the light detection means and the detection element are magnetic detection means and detection element. Examples of the magnetic detection element include a Hall element and an MR element which is a magnetoresistive element.

The magnetic encoder devices corresponding to the above are the following encoder devices. The magnetic encoder device described below can also detect the specific position in the same manner as the optical encoder device described above. A magnetic encoder scale having a magnetic encoder chart of standard pitch P formed by alternately arranging S poles of width P / 2 and N poles of width P / 2 in a predetermined direction; Magnetic detection means having first and second detection elements capable of detecting the magnetic field, and logical operation means capable of performing logical operation of respective detection signals of the two detection elements of the magnetic detection means. The width of the S pole or the N pole at at least one location in the encoder chart is α · P / 2 (α is a positive real number other than 1), and the first and second detection elements of the magnetic detection means are It is arranged at a position shifted by n · P + P / 2 (n is an integer of 0 or more) in the predetermined direction, and when the detection signals of the two detection elements are the same, the logical operation means outputs that fact. Magnetic encoder for logical operation Da device.
A magnetic encoder device driven by a driving unit to detect the position of a driven body moving in a predetermined direction, wherein an S pole having a width P / 2 and an N pole having a width P / 2 are alternately arranged in the predetermined direction. A magnetic encoder scale having a magnetic encoder chart of standard pitch P formed side by side, and a magnetic encoder scale arranged to face the chart and capable of detecting magnetism
Magnetic detection means having the detection element, encoder operation detection means capable of detecting the change state of the detection signal of the magnetic detection means, drive operation detection means capable of detecting the operation status of the drive means, and the encoder operation A logical operation means capable of performing a logical operation on each detection signal of the detection means and the drive operation detection means, wherein either one of the encoder scale or the magnetic detection means is fixedly arranged, and the other is arranged on the driven body. And the width of the S pole or the N pole at at least one location of the encoder chart is β · P / 2 (β is a real number greater than 1), and the logical operation means is Although the detection signal of the drive operation detecting means is a signal indicating that the drive means is operating, the detection signal of the encoder operation detecting means is When the detection signal of the magnetic detection means is a signal that does not change, a magnetic encoder device that performs a logical operation to output that effect.

Also in the above magnetic encoder device, the drive means is a motor having an armature coil, and the drive operation detecting means flows in the armature coil of the motor, as in the above optical encoder device. It includes a current sensor that can detect current. Also in this case, the drive operation detecting means is further provided with means capable of detecting the presence or absence of the detection signal of the current sensor, that is, the means capable of detecting whether or not a current is flowing in the armature coil. You can also

In the magnetic encoder device described above, a two-phase encoder device can be constructed as in the optical encoder device described above.
That is, in the above magnetic encoder device, the magnetic detection means is provided with a third detection element that is arranged so as to face the chart and can detect magnetism, and the third detection element is the first or the first detection element. It may be arranged so as to be offset from the second detection element by m · P + P / 4 (m is an integer of 0 or more) in the predetermined direction.

Further, in the above magnetic encoder device, the magnetic detection means is provided with a second detection element which is arranged to face the chart and is capable of detecting magnetism.
The second detection element may be arranged so as to be offset from the first detection element in the predetermined direction by m · P + P / 4 (m is an integer of 0 or more).

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A shows a linear type optical encoder device according to an embodiment of the present invention. Figure 1
(A) is a plan view showing a schematic configuration of the apparatus. Figure 1
The encoder device shown in (A) has an optical encoder scale 1 and an optical detector unit 21 arranged to face the scale. In this example, the scale 1 is fixed, and the detector unit 21 moves with respect to the scale 1. The detector unit 21 is fixed directly or indirectly to a driven body (not shown) driven by a driving means (not shown) and can move, and the encoder device detects the position and speed of the driven body. , Position control, speed control, etc.

The scale 1 has a high reflectance surface 11 having a width P / 2.
An optical chart 11 having a high-reflectance surface 11C in which A and a low-reflectance surface 11B having a width of P / 2 are alternately arranged in a straight line and a high-reflectance surface is formed in only one place with a width of 3 · P / 2 Is equipped with. The chart 11 has a high-reflectance surface 11A and a low-reflectance surface 11B that are adjacent to each other in a portion other than the high-reflectance surface 11C.
The standard pitch consisting of is P.

The detector unit 21 includes two detectors S1,
S2, each detector is P / 2 in the longitudinal direction of the scale 1.
They are arranged in a staggered manner. In addition, you may make it shift P / 2 + n * P (n is an integer greater than or equal to 1). Detector S1,
S2 has a light emitting element and a light receiving element, respectively.
These elements are arranged in the detector unit 21 so that the light emitting element emits light toward the chart 11 and the reflected light reflected by the chart 11 can be received by the light receiving element.

As described above, the high reflectance surface 11C has a width of 3 ·
P / 2 and that the detectors S1 and S2 are P /
Due to the two staggered arrangements, when the detector S1 faces the wide high reflectance surface 11C, the detector S2 may also be positioned on the high reflectance surface 11C. In this example, in FIG. 1 (A), when the detector S1 is located at a position facing within the width from the left end of the high reflectance surface 11C to the position moved by the distance P in the right direction, the detector S2 is also high. It is located at a position facing the reflectance surface 11C.

The detectors S1 and S2 are connected to the logical operation unit 31. The detection signals of the detectors S1 and S2 are photoelectrically converted by the light receiving element, further binarized, and output as a voltage signal. In this example, the high reflectance surfaces 11A, 1
When the detectors S1 and S2 receive the light reflected by 1C, that is, when the received light is bright (high brightness, high light intensity, etc.), in this example, the voltage “Hi” signal is output. It In addition, when the detectors S1 and S2 receive the light reflected by the low reflectance surface 11B, that is, when the received light is dark (low brightness, low light intensity, etc.), in this example,
The voltage "Lo" signal is output. The "Hi" or "L
In the voltage signal of “o”, the signal from the detector S1 is sg1 and the signal from the detector S2 is sg2.
Entered in.

The logical operation device 3 has an arithmetic circuit capable of performing a logical product (AND) operation. In the encoder device according to the present invention described above, the detector unit 2
When 1 moves, the detectors S1 and S2 output, for example, signals as shown in FIGS. 1B and 1C, respectively. In this case, the calculation result of the arithmetic unit 31 is shown in FIG. As shown.

That is, as described above, the detectors S1 and S2 are
May be at a position facing the high reflectance surface 11C, and at that position, the signal sg1 (output signal of the detector S1) and the signal sg2 (output signal of the detector S2) have the same "Hi". It becomes a signal. When located at other locations, the signals sg1 and sg2 have an inverted relationship (when one is “Hi”, the other is “Lo”).

Therefore, when the two detectors S1 and S2 are in that position, the output signal op1 of the arithmetic unit 3 is
When a logical product (AND) operation is performed, the signal becomes a "Hi" signal.
signal. In this way, the output signal op1 becomes the “Hi” signal only when both the detectors S1 and S2 are located on the high reflectance surface 11C, so that the position can be detected based on the signal op1. The position can be used as a specific position such as a predetermined reference position (origin position).

As described above, in the encoder device according to the present invention, since the detectors S1 and S2 for detecting the relative position also serve as the detectors for detecting the specific position, the detection dedicated to the detection of the specific position such as the reference position is performed. The child can be omitted.
Further, since the specific position can be detected with the same accuracy as the standard pitch P formed by the high reflectance surface 11A and the low reflectance surface 11B, the specific position can be detected with high accuracy. Further, the width of the high reflectance surface 11C indicating the specific position can be set arbitrarily.

Even if the arithmetic unit 3 performs a negation of exclusive OR (EX-NOR), the same result as in FIG. 1D can be obtained. In addition, NAND operation and exclusive O
When the R calculation is performed, an output result that is the inverse of the output result shown in FIG. 1D is obtained, and the specific position can also be detected by this. Instead of the detector unit 21 shown in FIG.
The detector unit 22 shown in FIG. 2 (A) can also be adopted. FIG. 2A is a plan view showing a schematic configuration of a linear type optical encoder device according to the present invention. Figure 2
The encoder device shown in FIG.
1A is the same as that shown in FIG. 1A except that it is different from that shown in FIG.

The detector unit 22 in the encoder device shown in FIG. 2A has three detectors S1, S2, S3.
have. These detectors are the same as those shown in FIG. The detectors S1 and S2 are P / 2 in the longitudinal direction of the scale 1 as shown in FIG.
They are arranged in a staggered manner. Further, the detector S3 is arranged in the longitudinal direction of the scale 1 so as to be displaced from the detectors S1 and S2 by P / 4. That is, the detector S
1, S3, and S2 are arranged in this order by shifting by P / 4.

Therefore, also in this encoder device, when the detector unit 22 moves in the longitudinal direction of the scale 1 and outputs, for example, as shown in FIGS. 2B, 2C and 2D, the calculation is performed. The detector S in the device 32
AND of the output signals sg1 and sg2 of 1 and S2
By taking, the calculation result shown in FIG. 2 (E) is obtained, and therefore the specific position can be detected. Further, in this encoder device, the detectors S1 and S
From the output signals of 3 (or the detectors S3 and S2), it is possible to obtain two-phase encoder signals with a phase angle difference of 90 degrees.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 3 is a plan view showing a schematic configuration of a linear type optical encoder device according to the present invention. This encoder device includes an encoder scale 1 having a chart 11 similar to that shown in FIG. 1 (A), a detector unit 23, and a computing device 33. The detector unit 23 has one detector S1, which is driven by a motor M in the longitudinal direction of the scale 1 to be driven 4
It is fixed to. An armature coil (not shown) of the motor M is connected to the motor drive device 5, and the motor drive device 5 causes a current to flow through the armature coil, whereby the motor M is driven and the driven body 4 is driven. It can be moved. The motor M is connected to a current sensor CS capable of detecting the current flowing through the armature coil. The detection signal of the current sensor CS is input to the arithmetic unit 32.

The arithmetic unit 32 can perform logical operations,
The presence / absence of the number of output pulses per unit time of the signal sg1 output by the detector S1 can be detected, that is, whether or not the detector S1 outputs a pulse per unit time can be detected. It is also possible to detect the presence / absence of a detection signal from the current sensor CS, that is, whether or not current is flowing through the armature coil of the motor M.

In this encoder device, for example, FIG.
When the driven body 4 is reciprocally moved in the longitudinal direction of the scale 1 in a speed pattern as shown in FIG.
In FIG. 3 (A), the position is moved from the left end position to the right,
When returning to the left end position again, the number of output pulses of the detection signal of the detector S1 per unit time is as shown in FIG. 3C, and the presence or absence of the output pulse is as shown in FIG. 3D. The presence or absence of the current detected by the current sensor CS is shown in FIG.
As shown in (E).

The presence / absence of the number of output pulses shown in FIG.
When passing through the wide high-reflectance surface 11C and when the driven body 4
Becomes 0 (in this example, this case is referred to as the "Lo" signal) when the speed of 0 becomes 0. On the other hand, the presence / absence of the current shown in FIG. 3 (E) is obtained only when the speed of the driven body becomes zero.
The value is 0 (in this example, this case is the “Lo” signal).

Therefore, a signal indicating the position of the high reflectance surface 11C shown in FIG. 3 (F) is obtained by performing an exclusive OR (EX-OR) operation of the signals in FIG. 3 (D) and (E). Can be obtained. The signal is the reference position (origin position)
It can be used to detect a specific position such as. Further, in this example, the detection signal of the current sensor CS can also be used for the abnormality detection of the motor M.

Although the optical encoder device described above is of the reflection type, it may be of the transmission type. In this case, for example, the high reflectance surfaces 11A and 11C
On the part of the transmission encoder scale other than the slit,
The portion of the low reflectance surface 11B may be the slit, and the light emitting element and the light receiving element of the detector may be opposed to each other with the scale in between.

A magnetic type may be used instead of the optical type. In this case, the high reflectance surfaces 11A and 11C are N poles (S poles), the low reflectance surfaces 11B are S poles (N poles), and the detector is a magnetic sensor such as a Hall element or a magnetoresistive element. It may be a certain MR element.

[0051]

According to the present invention, in the incremental encoder device, a dedicated detection element for detecting a specific position such as a reference position is not provided separately from the detection element for encoder chart detection. It is possible to provide an encoder device capable of accurately detecting a specific position such as a reference position.

[Brief description of drawings]

FIG. 1A is a plan view of a linear type optical encoder device according to an embodiment of the present invention, and FIGS. 1B and 1C are diagrams in which the detector unit shown in FIG. The figure which shows the example of the output signal which each detector outputs when it did, figure (D)
FIG. 4 is a diagram showing a result when logically operating the output signals of FIGS. (B) and (C).

FIG. 2A is a plan view of a linear type optical encoder device according to another embodiment of the present invention, and FIG.
(C) and (D) are diagrams showing examples of output signals output by each detector when the detector unit shown in (A) is moved, and (E) is a diagram of (B) and (C). It is a figure which shows the result at the time of carrying out the logical operation of the output signal.

FIG. 3A is a plan view showing a schematic configuration of a linear type optical encoder device according to still another embodiment of the present invention, and FIG. 3B is a driven body shown in FIG. It is a figure which shows the example of the speed pattern when is driven, FIG.
Is a diagram showing the number of output pulses per unit time of the detection element shown in FIG. 6B, and FIG. 6D is the presence or absence of the number of output pulses per unit time detected by the detection element of FIG. The figure, (E) is a figure which shows the presence or absence of the electric current detected by the current sensor shown in (A), and the figure (F) shows the result when logically operating the output signals of (D) and (E). FIG.

[Explanation of symbols]

1 Optical encoder scale 11 Optical encoder chart 11A, 11C High reflectance surface 11B Low reflectance surface 21, 22, 23 Detector unit S1, S2, S3 Optical detector 31, 32, 33 arithmetic unit 4 Driven body 5 drive M motor CS current sensor

Continuation of the front page (56) Reference JP-A-1-239463 (JP, A) JP-A-60-158313 (JP, A) JP-A-3-67122 (JP, A) Actual development Sho-60-118914 (JP , U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01D 5/00-5/62 G01B ⁷ /00-7/34 G01B 11/00-11/30

Claims (8)

(57) [Claims] 1. An optical encoder having a standard pitch P optical encoder chart formed by alternately arranging a low-reflectance surface having a width P / 2 and a high-reflectance surface having a width P / 2 in a predetermined direction. A scale, a photodetector arranged opposite to the chart, having first and second detectors capable of detecting light and darkness of light, and detection signals of the two detectors of the photodetector. And a width of at least one of the low light reflectance surface and the high light reflectance surface of the encoder chart is α · P / 2 (α is a positive value other than 1). Real number), and the first and second detection elements of the detection means are arranged at positions shifted by n · P + P / 2 (n is an integer of 0 or more) in the predetermined direction, and the logical operation means is When the detection signals of the two detection elements are the same, Optical encoder apparatus characterized by performing a logical operation to output the effect. 2. The light detecting means has a third detecting element which is arranged so as to face the chart and is capable of detecting light and darkness of light, and the third detecting element is the first or the second detecting element. The optical encoder device according to claim 1, wherein the optical encoder device is arranged so as to be offset from the detection element by m · P + P / 4 (m is an integer of 0 or more) in the predetermined direction. 3. An optical encoder device capable of detecting the position of a driven body which is driven by a drive means and moves in a predetermined direction, wherein the optical low reflectance surface has a width P / 2 and the light height has a width P / 2. An optical encoder scale having an optical encoder chart of standard pitch P formed by alternately arranging reflectance surfaces in the predetermined direction, and a first encoder arranged to face the chart and capable of detecting light and darkness of light. Light detection means having a detection element, encoder operation detection means capable of detecting the change state of the detection signal of the light detection means, drive operation detection means capable of detecting the operation status of the drive means, and encoder operation detection Means and a logic operation means capable of performing a logic operation on each detection signal of the drive operation detection means, and either one of the encoder scale or the light detection means is fixedly arranged. The other is disposed on the driven body and can move together with the driven body, and the width of the low-reflectance surface or the high-reflectance surface of at least one portion of the encoder chart is β · P / 2 (β Is a real number greater than 1), and the logical operation means outputs the detection signal of the drive operation detection means, although the detection signal of the drive operation detection means is a signal indicating that the drive operation is operating. When the detection signal is a signal indicating that there is no change in the detection signal of the light detection means, a logical operation is performed to output that effect, and the drive means is a motor having an armature coil, and the drive operation detection An optical encoder device, wherein the means includes a current sensor capable of detecting a current flowing through an armature coil of the motor. 4. The light detection means includes a second detection element which is arranged so as to face the chart and can detect light and darkness of light, and the second detection element includes the first detection element and the first detection element. The optical encoder device according to claim 3, wherein the optical encoder device is arranged so as to be displaced in a predetermined direction by m · P + P / 4 (m is an integer of 0 or more). 5. A magnetic encoder scale having a magnetic encoder chart of standard pitch P formed by alternately arranging S poles of width P / 2 and N poles of width P / 2 in a predetermined direction, and a magnetic encoder scale on the chart. Magnetic detection means having first and second detection elements arranged facing each other and capable of detecting magnetism, and a logic capable of performing a logical operation of each detection signal of the two detection elements of the magnetic detection means. A width of at least one of the S poles or N poles of the encoder chart is α · P / 2 (α is a positive real number other than 1), and the first and second magnetic detection means are provided. The two detection elements are arranged at a position shifted by n · P + P / 2 (n is an integer of 0 or more) in the predetermined direction, and the logical operation means, when the detection signals of the two detection elements are the same, Perform a logical operation to output that effect Magnetic encoder apparatus according to claim and. 6. The magnetic detection means has a third detection element which is arranged so as to face the chart and can detect magnetism, and the third detection element is the first or second detection element. 6. The magnetic encoder device according to claim 5, wherein the magnetic encoder device is arranged so as to be shifted by m · P + P / 4 (m is an integer of 0 or more) in the predetermined direction. 7. A magnetic encoder device which is driven by a driving means and can detect the position of a driven body which moves in a predetermined direction, wherein an S pole of width P / 2 and an N pole of width P / 2 are provided. A magnetic encoder scale having a magnetic encoder chart of standard pitch P formed alternately in a predetermined direction, and a magnetic detecting means having a first detecting element arranged to face the chart and capable of detecting magnetism. An encoder operation detection means capable of detecting a change state of a detection signal of the magnetic detection means, a drive operation detection means capable of detecting an operation status of the drive means, and an encoder operation detection means and a drive operation detection means And a logical operation means capable of performing a logical operation of the detection signal, one of the encoder scale or the magnetic detection means is fixedly arranged, the other is The width of the S pole or the N pole at at least one position of the encoder chart is β · P / 2 (β is a real number larger than 1), which is disposed on the driven body and can move together with the driven body. In the logical operation means, the detection signal of the encoder operation detection means is the detection signal of the magnetic detection means, although the detection signal of the drive operation detection means is a signal indicating that the drive means is operating. When it is a signal indicating that there is no change, a logical operation is output to that effect, the driving means is a motor having an armature coil, and the driving operation detecting means is a motor armature coil. A magnetic encoder device comprising a current sensor capable of detecting a flowing current. 8. The magnetic detection means includes a second detection element that is arranged so as to face the chart and is capable of detecting magnetism, and the second detection element includes the first detection element and the predetermined direction. 8. The magnetic encoder device according to claim 7, wherein the magnetic encoder device is arranged so as to be displaced by m · P + P / 4 (m is an integer of 0 or more).