JPH08271287A - Displacement information detecting device, drive control device using the detecting device, and scale device - Google Patents

Abstract

PURPOSE: To provide a displacement information detecting device which can be made small in size without the deterioration of the accuracy in detection, a drive control device using the detecting device, and a scale device being suitable for the displacement information detecting device, in an apparatus wherein optical systems based on different principles of detection are provided together. CONSTITUTION: In an apparatus wherein the information on rotation of a scale member D is detected by detecting the information on the interference of diffracted light generated by radiating a light flux to a diffraction grating GT provided on the scale member D, a constitution for detecting light from data recording parts Z1, Z2, U, V and W so as to detect the information on rotation of the scale member D is provided separately and the diffraction grating GT and the data recording parts Z1, Z2, U, V and W on the scale member D are formed by different manufacturing methods.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement information detecting device and a drive control device using the displacement information detecting device. The present invention, in particular,
By irradiating the radial diffraction grating and the code pattern of the disk attached to the relative rotating object with a light beam, and detecting the modulated signal light obtained therefrom, the rotational position of the disk, the rotational position deviation amount, the rotational position deviation direction, A rotary encoder that detects rotation speed, rotation acceleration, etc., and a device that controls the current amount and direction of a drive device such as an AC motor based on the above detection information to rotate the object (motor with encoder, etc.) It can be applied well to

[0002]

2. Description of the Related Art Conventionally, an incremental rotary encoder has been used for the purpose of highly accurately measuring rotation information (rotational displacement amount, speed, acceleration, etc.) of an object. On the other hand, for brushless motors typified by AC motors,
An absolute rotary encoder that detects the absolute rotational position of the rotor in the motor is used to rotate the motor.

Therefore, in order to control the rotational position of an object using an AC motor or the like, a composite rotary encoder that can obtain both signals is used.

A highly accurate incremental encoder is
A micron-order fine grating recorded on a scale is illuminated with a monochromatic light beam, and at least two of the diffracted light obtained there are extracted and caused to interfere, causing a periodic change in the amount of light with the movement of the grating. Is generated and detected by a photoelectric element to output an incremental encoder signal.

The absolute rotary encoder is
If a plurality of transmissive / non-transmissive (or reflective / non-reflective) patterns (for example, gray code patterns) are formed on the circumference of different radii on the rotating disk so that only one code is combined in one rotation, The absolute rotation position of the disk is output by detecting transmitted light (or reflected light) at a specific position on each circumference.

In the absolute encoder for a motor, a plurality of transmission non-transmission (or reflection non-reflection) patterns (for example, gray code patterns) are provided on the circumference of the rotating disk having different radii, and the structure of the motor (number of poles M). If it is formed so that there is only a combination of M cords,
The position between the rotor and the stator of the motor is output by detecting the transmitted light (or the reflected light) at a specific position on each circumference.

[0007]

As a recent trend, there is a demand for miniaturization of encoders (EX.Φ10 mm disc). However, it is difficult to miniaturize composite encoders based on different principles as described above. It was difficult.

Optical systems based on different detection principles can be simply installed to reduce the size of each, but there is a limit to downsizing, and there is a demand for a device that can be downsized without degrading detection accuracy. Was there.

In view of the above-mentioned conventional example, the present invention is a device provided with an optical system based on a different detection principle, which can be miniaturized without degrading detection accuracy, a drive control device using the same, and An object of the present invention is to provide a scale device suitable for such a displacement information detecting device.

[0010]

According to a first aspect of the present invention, a diffraction grating provided on a scale member for detecting relative rotation is irradiated with a luminous flux so that diffracted light generated by the diffraction grating is interfered with. A device for detecting rotation information of the scale member by detecting information on the interference, the scale means having the diffraction grating and a data recording unit recording rotation information; and rotation information of the scale member. It has first detecting means for detecting the light diffracted from the diffraction grating by interfering for detecting, and second detecting means for detecting light from the data recording portion for detecting rotation information of the scale member. The displacement information detecting device is characterized in that the diffraction grating on the scale and the data recording portion are formed by different manufacturing methods.

The second invention is characterized in that, in the above-mentioned structure, the second detecting means detects a pattern for detecting an absolute position or a pattern for detecting an origin.

A third aspect of the present invention is characterized in that, in the above-mentioned structure, the diffraction grating and the data recording section are formed on surfaces having different scales.

A fourth aspect of the present invention is a drive control system including the displacement information detecting device as described above.

A fifth aspect of the invention is a scale device used in a device for interfering diffracted light generated by irradiating a diffraction grating with a light beam and detecting information on the interference to detect rotation information of an object. A substrate, a diffraction grating provided on one surface of the substrate, and a data recording section optically detected to detect rotation information of the scale member, the data recording section being the diffraction grating. The scale device is characterized in that it is formed on a surface different from.

[0015]

1 to 5 are explanatory views of a rotary encoder according to a first embodiment of the present invention. FIG. 1 is an optical layout diagram of the apparatus of this embodiment, FIG. 2 is an enlarged view thereof, FIG. 3 is a schematic optical path diagram of the apparatus, FIG. 4 is a diagram showing a pattern shape in the apparatus, and FIG. 5 is a disk structure portion. FIG. In the figure, all members except the disk D and the pattern formed thereon are fixedly arranged on the apparatus main body (not shown) on the fixed side, and the disk D is a rotating member (not shown) such as a shaft. It is installed with the disk center aligned with the center of rotation.

The light-receiving element array SARY includes an incremental detector SA, SB, S bar A, S bar B, and an origin code detector.
It consists of SZ1, SZ2 and absolute code detectors SU, SV, SW.

A light beam emitted from a light source LGT such as an LED is converted into a parallel light beam R by a collimator lens LNS1 and illuminated on a disk D which rotates relatively.

On the disk D, a transmission type radial diffraction grating GT which is glass-etched or replica-molded, and a non-transparent origin pattern Z and a non-transparent pattern Z formed by etching a metal (here, chromium) vapor deposition film or the like. On the circumference (on the track) where the absolute code patterns U, V, and W are different from each other by the different manufacturing method as described above, the origin pattern Z is located near the origin target position of the disk D, and the absolute code patterns U and V , W are recorded over the entire circumference of the disc D, respectively. FIG. 5 shows the details of this configuration.

As shown in FIG. 2, the collimated light beam is emitted from the disk D.
In the radial direction of, the area where the radial grating GT is formed, the origin code pattern Z is formed, and the absolute code patterns U, V, and W are formed in the partial areas can be collectively illuminated. Have In FIG. 2, only the light flux portion incident on each sensor described later is shown.

Assuming that the radial grating GT is N in number around the circumference of the disk, two ± 1st-order diffracted light beams R + and R- are generated by the radial grating GT (grating pitch P = 2π / N radian). These two ± 1st-order diffracted light beams R + and R- are the first radial diffraction grating GBS1 (grating pitch P = π / N) provided on the apparatus main body side.
It is diffracted by radians, the optical path is bent, and converted into luminous fluxes R +-and R- +. A second radial diffraction grating GBS2 is arranged at a point on the space where the light fluxes R +-and R- + intersect. The light fluxes R +-and R- + are diffracted by the second diffraction grating GBS2 (grating pitch P = 2π / N radian) and the light flux R +-
It becomes +, R-+-, and they overlap each other and interfere with each other, and they are emitted as bright and dark signal light (see FIG. 3).

Here, the first and second diffraction gratings GBS1 and GBS2
The radiation grating GT has a fine structure that does not generate 0th-order diffracted light in the lamella phase grating. The first and second
The diffraction gratings GBS1 and GBS2 are radial with the center of rotation of the disk D as the approximate center, and are partially formed along the entire circumference of the disk D.

The diffraction grating GBS2 is, as shown in FIG.
The region is divided into four with the point P0 as a boundary, and the phases of the lattice arrangements are mutually shifted by ⅛ pitch.

The luminous fluxes R +-+ and R-+-diffracted by the diffraction grating GBS2 are emitted so that the optical paths of their optical axes are overlapped with each other and their optical axes are parallel to each other. Symmetry is maintained and interferes with each other.

At this time, when the radial grating moves 1 pitch by the rotation of the disk in the diffracted light R +-+, the phase of the wavefront shifts by + 2π, and the diffracted light R-+-moves the pitch of the radial grating by 1 pitch by the rotation of the disk D. When moved by a minute, the wavefront phase is -2.
It deviates by π. Therefore, when the radial grating moves by one pitch due to the rotation of the disc, the interference light becomes bright and dark with a sine wave shape.
Change times.

Further, as described above, in the diffraction grating GBS2, the area is divided into four with the point P0 as a boundary, and the phases of the grating arrangement are shifted by ⅛ pitch. The interference phase (bright and dark phases) in the region shifts by ¼ cycle from each other and changes twice in a sinusoidal manner.

Since the interference light from each of these regions is incident on the corresponding light receiving element SA, SB, S bar A, S bar B, 1 from the light receiving elements SA, SB, S bar A, S bar B.
By rotation, the 2N cycle sinusoidal analog signal currents are 1
It occurs with a shift of / 4 cycle. A relative incremental rotation amount and rotation direction of the disk D are calculated by a signal processing circuit (not shown) using the four phase-shifted sinusoidal analog signals. Since this calculation is well known, its explanation is omitted.

Since the luminous flux R illuminating the disc D has a divergence, even when it reaches the diffraction grating GBS1 after being diffracted by the radial grating GT, the diffraction gratings GBS1 and GBS1 and G2 are almost overlapped with each other.
It is guided to the light receiving element through BS2.

For example, the luminous flux diameter for illumination is 500 μm, the number of radial gratings N = 2500, the recording radius on the disk D is r = 5000 μm,
When the LED wavelength is λ = 0.86 μm, the first-order diffraction angle is θ = arcsin {λ · N / (2πr)} = 3.92 °. Gap between radial grating GT and diffraction grating GBS1 h ＝
Assuming 500 μm, the separation amount is 68.5 μm.

On the other hand, the origin code pattern Z is composed of two light non-transmissive patterns which are displaced from each other in the circumferential direction as shown in FIG. 2, each of which is arranged corresponding to the radial position of each of the light receiving elements SZ1 and SZ2. Has been done. Origin code pattern Z
When the above-mentioned parallel luminous flux is illuminated by, the transmitted light of the amount of light corresponding to the circumferential position thereof is incident on the light receiving elements SZ1 and SZ2. When the origin code pattern Z moves within the illumination area due to the rotation of the disk D, the transmitted light of the origin code pattern Z changes in the cross section of the transmitted light projected on the light receiving elements SZ1 and SZ2.
As a result, the total luminous flux amount with which the light receiving elements SZ1 and SZ2 are illuminated changes. At this time, due to the pattern arrangements that are displaced from each other in the circumferential direction as described above, the received light amounts of the light receiving elements SZ1 and SZ2 are deviated from each other at the timings when the light amounts change. Therefore, the light receiving element
From SZ1 and SZ2, valley-shaped waveform analog signal currents whose peaks are offset from each other are generated by the rotation of the disk D. As the origin signal, for example, a pulse signal may be generated when the outputs of the light receiving elements SZ1 and SZ2 match. Such a pulse signal is generated by a signal processing circuit (not shown) that receives the outputs of the light receiving elements SZ1 and SZ2. As a result, the passage of the origin of the disk D is detected.

On the other hand, the absolute code patterns U, V,
The parallel light flux illuminating the track where W is present determines whether or not the light flux part irradiated to the part corresponding to the light receiving element is on the absolute code patterns U, V, W, that is, the light receiving element of the absolute code pattern track. Depending on whether the light beam is transmitted or not transmitted in the area corresponding to
The rotation of D causes the transmitted light to be intermittently projected on the light receiving elements SU, SV, and SW, respectively. The light receiving elements SU, SV, SW output an absolute code signal group according to the current rotational position of the disk D, and the absolute position is specified by a signal processing circuit (not shown) by the combination of the binary information.
Since the method of specifying the absolute position is well known, the description thereof will be omitted.

In this way, the light modulated in each area is incident on each corresponding light receiving element on the light receiving element array SARY.

In the apparatus of the first embodiment, in the apparatus for detecting the rotation information using the grating interference method, even if the rotation information detecting section based on the different detection principle is installed side by side to reduce the size, the pattern for each detection is obtained. By adopting a configuration in which each is formed by a different manufacturing method, each can be manufactured with a configuration suitable for high-precision detection without being influenced by each other's manufacturing, and each detection can be performed with high accuracy.

The optical system of the first embodiment may be partially modified so that the incremental interference light, the absolute code pattern, and the origin code pattern are projected onto the light receiving element array SARY by the imaging projection lens. Good. Such lens projection improves the resolution of the edges of the absolute pattern and the origin pattern, and improves the detection accuracy.

FIG. 6 shows a modification of the pattern arrangement on the disk D in the first embodiment. In FIG. 6, an enlarged view of the disk structure portion similar to that of FIG. 5 is shown.

In this modification, the radial diffraction grating GT is formed on the back side of the disk D in the drawing as compared with the first embodiment.
Thus, the radial grating GT and the absolute pattern
U, V, W and origin code patterns Z1, Z2 may be separately arranged on both surfaces of the transparent substrate. In this case, there is an advantage that the pattern can be formed by a different process for each surface and the formation is facilitated.

7 to 11 are explanatory views of a rotary encoder according to the second embodiment of the present invention. FIG. 7 is an optical layout diagram of the device of the present embodiment, FIG. 8 is an enlarged view thereof, FIG. 9 is a schematic view of the optical path of the device, FIG. 10 is a diagram showing a pattern shape in the device, and FIG. 11 is a disk structure portion. FIG. In the figure, all members except the disk D and the pattern formed thereon are fixedly arranged on the apparatus main body (not shown) on the fixed side, and the disk D is a rotating member (not shown) such as a shaft. It is installed with the disk center aligned with the center of rotation. Parts similar to those previously described are given the same reference numerals.

In this embodiment, the reflected diffracted light from the radial diffraction grating GT on the disk D is used. Hereinafter, description will be made step by step as in the first embodiment.

A light beam emitted from a light source LGT such as an LED is converted into a parallel light beam R by a collimator lens LNS1, passes through a beam splitter BS, and a part of the light beam is a first diffraction grating.
It is illuminated via GBS3 onto disk D, which is relatively rotating as a whole.

On the disk D, a reflection type radial phase type diffraction grating GT having a reflecting film or the like on a concavo-convex surface that has been subjected to glass etching, etc., and a non-reflecting origin point where the reflecting film or the like is partially removed by etching. Pattern Z and the non-light-reflecting absolute code patterns U, V, W are manufactured on different circumferences, and the origin pattern Z is located near the target position of the disk D and the absolute code patterns U, V, W Are recorded over the entire circumference of disc D, respectively.
FIG. 11 shows the details of this configuration.

As described above, a part of the luminous flux of the illumination luminous flux is the first diffraction grating GBS3 (grating pitch P = 4π / N radian).
Incident on. Two diffracted lights R + and R- are generated by the first diffraction grating GBS3, and illuminate the disk D which rotates relative to each other. The light flux that does not pass through the area of the diffraction grating GBS3 is illuminated on the disk D that relatively rotates as it is. Therefore, the partial areas of the track on which the radial grating GT is formed, the track on which the origin code patterns Z1 and Z2 are formed, and the tracks on which the absolute code patterns U, V, and W are formed are collectively illuminated.

Assuming that there are N radial gratings GT around the circumference of the disk, the radial grating GT (grating pitch P = 2π / N radian) produces two ± first-order reflected diffracted light beams R + −, R− +. These two ± 1st-order reflected diffracted light beams R +-, R- + are re-diffracted by the first diffraction grating GBS3 (grating pitch P = 4π / N radian) and their optical paths are superposed, and the light beams R +-+, R-
It becomes +-, which interferes with each other and emits as a light-dark signal (see FIG. 9).

Here, the first diffraction grating GBS3 and the radiation grating GT have a fine structure such that 0th-order diffracted light is not generated in the lamella phase grating. In addition, the third diffraction grating GBS3
Are radial with the center of rotation of the disk D as the approximate center, and are partially formed on the entire circumference of the disk D.

As shown in FIG. 10, the diffraction grating GBS3 is divided into four areas with the point P0 as a boundary, and the phases of the grating arrays are shifted by ⅛ pitch.

The light beams R +-+ and R-+-generated by being re-diffracted from the diffraction grating GBS3 are emitted so that the optical paths of their optical axes are overlapped with each other and their optical axes are parallel to each other. Symmetry is maintained and they interfere with each other.

At that time, when the radial grating moves 1 pitch by the rotation of the disk in the diffracted light R +-+, the phase of the wavefront shifts by + 2π, and the diffracted light R-+-moves the pitch of the radial grating by 1 pitch by the rotation of the disk D. When moved by a minute, the wavefront phase is -2.
It deviates by π. Therefore, when the radial grating moves by one pitch due to the rotation of the disc, the interference light becomes bright and dark with a sine wave shape.
Change times.

Further, as described above, in the diffraction grating GBS3, the region is divided into four parts with the point P0 as the boundary, and the phases of the grating arrays are shifted by ⅛ pitch. The interference phase (bright and dark phase) in the region shifts by 1/4 cycle and changes twice in a sinusoidal manner.

Interference light from each of these areas is passed through the beam splitter BS and the corresponding light receiving element SA, SB, S is received.
Since the light enters the bars A and S bar B, the light receiving elements SA and S
From B, S bar A, and S bar B, sinusoidal analog signal currents of 2N cycles are generated with a 1/4 cycle offset from each other in one rotation. A relative incremental rotation amount and rotation direction of the disk D are calculated by a signal processing circuit (not shown) using the four phase-shifted sinusoidal analog signals. Since this operation is well known,
Description is omitted.

Since the light flux R illuminating the disc D has a spread, even if it reaches the radial grating GT after being diffracted by the diffraction grating GBS3, it is guided to the light receiving element through the diffraction grating GBS3 with almost overlapping.

For example, the luminous flux diameter for illumination is 500 μm, the number of radial gratings N = 2500, the recording radius on the disc D is r = 5000 μm,
When the LED wavelength is λ = 0.86 μm, the incident angle of the disc illumination light is θ = arcsin {λ · N / (4πr)} = 1.96 °. Gap between radial grating GT and diffraction grating GBS3 h ＝
Assuming 500 μm, the separation amount is 34.2 μm.

On the other hand, the origin code pattern Z is composed of two light non-reflective patterns which are displaced from each other in the circumferential direction as shown in FIG. 8, and each of them is arranged corresponding to the radial position of the light receiving elements SZ1 and SZ2. Has been done. Origin code pattern Z
When is illuminated with the above-mentioned parallel luminous flux, reflected light of a light amount corresponding to the circumferential position thereof is incident on the light receiving elements SZ1 and SZ2 via the beam splitter BS. When the origin code pattern Z moves in the illumination area due to the rotation of the disk D, the reflected light of the origin code pattern Z changes in reflected light cross-sectional area projected on the light receiving elements SZ1 and SZ2. As a result, the light receiving element SZ
1. The total luminous flux quantity illuminating SZ2 changes. At this time, due to the pattern arrangements that are displaced from each other in the circumferential direction as described above, the received light amounts of the light receiving elements SZ1 and SZ2 are deviated from each other at the timings when the light amounts change. Therefore, from the light receiving elements SZ1 and SZ2,
The rotation of D produces a valley-shaped analog signal current whose peaks are offset from each other. As the origin signal, for example, a pulse signal may be generated when the outputs of the light receiving elements SZ1 and SZ2 match. Such a pulse signal is received by the light receiving element SZ.
1. Generated by a signal processing circuit (not shown) that receives SZ2 output. As a result, the passage of the origin of the disk D is detected.

On the other hand, the absolute code patterns U, V,
The parallel light flux illuminating the track where W is present determines whether or not the light flux part irradiated to the part corresponding to the light receiving element is on the absolute code patterns U, V, W, that is, the light receiving element of the absolute code pattern track. Depending on whether the light beam is transmitted or not transmitted in the area corresponding to
The rotation of D causes the reflected light to be intermittently projected onto the light receiving elements SU, SV, SW via the beam splitter BS. The light receiving elements SU, SV, SW output an absolute code signal group according to the current rotational position of the disk D, and the absolute position is specified by a signal processing circuit (not shown) by the combination of the binary information. Since the method of specifying the absolute position is well known, the description thereof will be omitted.

In this way, the light modulated in each area is incident on each corresponding light receiving element on the light receiving element array SARY.

Also in the apparatus of the second embodiment, in the apparatus for detecting the rotation information by using the grating interference method, even if the rotation information detecting section based on the different detection principle is installed side by side to reduce the size, each detection pattern is detected. By adopting a configuration in which each is formed by a different manufacturing method, each can be manufactured with a configuration suitable for high-precision detection without being influenced by each other's manufacturing, and each detection can be performed with high accuracy.

A part of the optical system of the second embodiment is modified so that the incremental interference light, the absolute code pattern,
The origin code pattern may be projected on the light receiving element array SARY by the imaging projection lens. With such a configuration, the resolution of the edges of the absolute pattern and the origin pattern is improved, and the detection accuracy is improved.

FIG. 12 shows a disk D according to the second embodiment.
It is a modification of the above pattern arrangement. In FIG. 12, an enlarged view of the disk structure portion similar to that of FIG. 11 is shown.

In this modification, the radial diffraction grating GT, the absolute patterns U, V and W, and the origin code pattern Z are provided in the second embodiment in which each pattern is provided on the upper surface of the disk D.
1 and Z2 are arranged on the lower surface (back surface) of the transparent substrate. By doing so, the pattern can be arranged on the side opposite to other optical arrangements, and the possibility of pattern damage due to contact or the like can be reduced.

FIG. 13 is a schematic configuration diagram of a motor driver system according to the third embodiment of the present invention. DH in the figure
Is a detection head in which an all-optical configuration excluding the disk D from the light source LGT to the light receiving element array SARY in any of the above-described first and second embodiments and their modifications, P
U is a signal processing circuit, IM, which processes the output from each light receiving element of the light receiving element array SARY to perform incremental rotation amount and rotation direction measurement, discrete rotation position measurement, and origin detection, and generates a control signal. Is an input unit for inputting a rotation command to the signal processing circuit PU, MD is a motor driver that receives a control signal from the signal processing circuit PU and controls the drive of the motor, MT is a motor, and SF is rotationally driven by the motor. , A shaft for transmitting a driving force to a driven part (not shown).

The signal processing circuit PU generates a control signal based on the output from each light receiving element of the light receiving element array SARY and the command input information from the input section, whereby the rotational drive of the shaft SF by the motor MT is controlled. It

Even if the detection head DH is downsized by the above-described structure, it is possible to realize a motor driver system which can detect each rotation information with high accuracy and can perform accurate control with a more compact structure.

Others The optical system can be developed by the following modifications. (1) In the optical path of separation, deflection, and combination by the diffraction grating, the number N1 of first radial diffraction gratings (line / circle), the number of second radial diffraction gratings N2 (line / circle), third radial diffraction The number of grids N3 (lines / circle) may be changed and configured so as to satisfy n1 · N1 + n2 · N2 + n3 · N3 = 0.

However, n1, n2, and n3 are diffraction orders by the first, second, and third diffraction gratings, and the number N of radial diffraction gratings that need not be recorded in the entire circumference does not have to be an integer and is a decimal point. May be attached. In the first embodiment, n1 = + 1, n2 =-
1, n3 = + 1, N1 = 2500, N2 = 5000, N3 = 2500. (2) The absolute pattern UVW may be changed to normal pure binary code, gray code, etc. instead of for motor control. (3) The relationship of transmission, non-transmission or reflection, and non-reflection of the absolute pattern and Z pattern may be reversed. (4) The number of divisions of the diffraction grating for generating an incremental phase difference signal (GBS2 in the first embodiment) and the amount of phase shift are changed (two divisions, 90 degrees shift, or six divisions, 60 degrees shift). Etc.) (5) Instead of dividing the detection pattern of the origin into two such as Z1 and Z2 and obtaining it from the difference signal of two signals, the method of detecting the peak of the correlation function by superposition of two normal random pitch patterns is adopted. You may change it. (6) In the above-mentioned embodiment, the example of the device for detecting the rotation information as the displacement information has been described, but the disk D may be replaced with the device for detecting the linear motion information by using the linear motion scale.

[0062]

As described above, according to the first aspect of the present invention, two different disc patterns can be simultaneously read with high accuracy, and a displacement information detecting device that is compact and obtains high resolution displacement information is realized. .

Further, according to the second aspect of the present invention, the detection of the interference method and the absolute rotation detection or the origin detection can be simultaneously performed with high accuracy, and the displacement information which can obtain the rotation information with a high resolution while being small in size. The detector is realized.

Further, according to the third invention, it is possible to form the patterns respectively suitable for the two different detection principles on different surfaces, which facilitates the production.

Further, according to the fourth aspect of the invention, even if the detector is downsized, each rotation information can be detected with high accuracy, and accurate control can be realized with a more compact structure.

Further, according to the fifth aspect of the invention, a scale device which can form patterns suitable for two different detection principles on different surfaces and is easy to manufacture has been realized.

[Brief description of drawings]

FIG. 1 is an optical layout diagram of an apparatus according to a first embodiment of the present invention.

[Figure 2] Enlarged view

FIG. 3 is a schematic diagram of the optical path of the device.

FIG. 4 is a diagram showing a shape of a pattern in the apparatus.

FIG. 5 is an enlarged view of a disk structure portion.

FIG. 6 is a diagram showing a modification of the first embodiment.

FIG. 7 is an optical layout diagram of an apparatus according to a second embodiment of the present invention.

[Figure 8] Enlarged view

FIG. 9 is a schematic diagram of the optical path of the device.

FIG. 10 is a diagram showing the shape of a pattern in the same device.

FIG. 11 is an enlarged view of a disk structure portion.

FIG. 12 is a diagram showing a modification of the second embodiment.

FIG. 13 is a schematic configuration diagram of a motor drive system according to a third embodiment of the present invention.

[Explanation of symbols]

LGT Light source R Luminous flux LNS1, LNS2 Lens D Relative rotation disc GBS1, GBS2 (Radial) diffraction grating GBS3 (Radial) diffraction grating GT Radial diffraction grating on disk P0 GBS2 or GBS3 Combined light flux position SA, S bar A, SB, S bar B Interference light receiving element SZ1, SZ2 Origin signal code pattern light receiving element SU, SV, SW Absolute signal code pattern light receiving element Z1, Z2 Origin detection pattern U, V, W Absolute code signal pattern

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G11B 19/06 501 G11B 19/06 501E 19/20 19/20 G

Claims (5)

[Claims] 1. Diffraction light generated by irradiating a diffraction grating provided on a scale member for detecting relative rotation with each other is caused to interfere, and information on the interference is detected to obtain rotation information of the scale member. An apparatus for detecting, wherein the diffracted light from the diffraction grating is detected by interfering with the scale means provided with the diffraction grating and the data recording section recording rotation information, and the rotation information of the scale member to detect the rotation information. The first detection means and the second detection means for detecting the light from the data recording portion to detect the rotation information of the scale member are provided, and the manufacturing method is different between the diffraction grating on the scale and the data recording portion. Displacement information detection device characterized in that it is formed by. 2. The displacement information detecting device according to claim 1, wherein the second detecting means detects a pattern for absolute position detection or a pattern for origin detection. 3. The displacement information detecting apparatus according to claim 1, wherein the diffraction grating and the data recording section are formed on different surfaces of the scale. 4. A drive control system comprising the displacement information detecting device according to claim 1. Description: 5. A scale device used in a device for interfering diffracted light generated by irradiating a diffraction grating with a light flux and detecting information on the interference to detect rotation information of an object, the scale device comprising: a substrate; A diffraction grating provided on one surface of the substrate, and a data recording section optically detected to detect rotation information of the scale member, the data recording section being a surface different from the diffraction grating. A scale device characterized in that it is formed on.