JP5862672B2 - Encoder device and device - Google Patents

Description

The present invention relates to an encoder device and an apparatus.
This application claims priority based on Japanese Patent Application No. 2011-181401 for which it applied on August 23, 2011, and uses the content here.

  In recent years, a scale that has a pattern that moves with a moving body and has a pattern formed along the moving direction is irradiated with modulated irradiation light, and the reflected or transmitted light is received, and the light received according to the received light. An encoder device that detects scale position information based on a signal has been proposed (see, for example, Patent Document 1 and Patent Document 2). Such an encoder device obtains a phase-modulated light reception signal by, for example, modulating illumination light emitted from a single light source using a movable part such as an actuator.

US Pat. No. 6,639,686 JP 2006-343314 A

  In a conventional encoder device, a movable part such as an actuator is used, so that the structure is complicated, and a complex structure including the movable part is adjusted to obtain a phase-modulated received light signal. In such a case, the error of each component including the movable part is accumulated, and the detection accuracy of the scale position information may be reduced.

  An object of an aspect of the present invention is to provide an encoder apparatus and apparatus that can detect position information with high accuracy.

  In one embodiment of the present invention, a light source unit including a first light source unit that emits first irradiation light and a second light source unit that emits second irradiation light, the light amount of the first irradiation light, and the second irradiation. A modulation unit that periodically modulates the amount of light with different phases, and is movable relative to the light source unit at least in a moving direction, and the first irradiation light and the second irradiation light are incident thereon, The scale having a pattern formed along the moving direction and the first irradiation light and the second irradiation light having a predetermined phase difference from each other are received, and the received first irradiation light and the second irradiation light are received. A light receiving unit that outputs a light reception signal corresponding to the irradiation light; and a position detection unit that detects a position of the scale in the movement direction based on the light reception signal, wherein the second light source unit includes the first light source unit. The second irradiation light having a wavelength different from that of the irradiation light is emitted, and the front It is arranged in at least one of the first optical path and the second optical path among the optical paths of the first irradiation light and the second irradiation light between the light source unit and the light receiving unit, and the predetermined phase difference is set. An encoder device including an optical member to be generated.

  Yet another embodiment of the present invention is an apparatus comprising: the encoder device described above; and a moving body connected to the scale or a detection head of the encoder device.

  According to the aspect of the present invention, position information can be detected with high accuracy.

It is a schematic block diagram which shows the structure of the encoder apparatus by 1st Embodiment. It is a schematic diagram which shows the structure of the detection head and scale in the embodiment. It is a schematic diagram which shows the structure of the detection head and scale in the embodiment. It is a schematic diagram which shows the structure of the detection head and scale in the embodiment. It is a figure explaining the irradiation light by the 1st light source part and the 2nd light source part in the embodiment. It is a figure explaining the irradiation light by the 1st light source part and the 2nd light source part in the embodiment. It is a figure which shows the waveform of the received light signal by the irradiation light of the 1st light source part in the same embodiment, and a 2nd light source part. It is a schematic block diagram which shows the encoder apparatus by 2nd Embodiment. It is a figure which shows the waveform of the light quantity modulation signal and light reception signal in the embodiment. It is a schematic diagram which shows the structure of the 1st modification of a detection head and a scale. It is a schematic diagram which shows the structure of the 2nd modification of a detection head and a scale. It is a schematic diagram which shows the structure of the 2nd modification of a detection head and a scale. It is a schematic diagram which shows the structure of the 2nd modification of a detection head and a scale. It is a schematic block diagram which shows the structure of a stage apparatus.

  Hereinafter, an encoder apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic block diagram showing a configuration of an encoder device 1 (position detection device) according to the first embodiment.
2A, 2B, and 2C are schematic diagrams illustrating the configuration of the detection head 9 and the scale 6 of the encoder device 1. FIG. 2A-2C, the following description will be made assuming that the moving direction of the scale 6 is the X-axis direction and the irradiation direction of the light source unit 2 is the positive direction of the Y-axis.
Here, FIG. 2A is a diagram (a diagram in a direction along the Z axis) illustrating the case where the detection head 9 and the scale 6 are viewed from the Z axis direction. FIG. 2B is a diagram (a diagram in a direction along the X axis) illustrating the case where the detection head 9 and the scale 6 are viewed from the X axis direction. 2C is a diagram (a diagram in the direction along the Y axis) showing the detection head 9 (detection substrate 70) viewed from the scale 6 side (from the Y axis direction).

The encoder device 1 is an optical linear encoder that detects position information (for example, the moving direction, moving amount, or displacement of the scale 6) of the scale 6 that moves in a predetermined moving direction (for example, the X-axis direction). . 1 and 2A-2C, the encoder device 1 includes a scale 6, a detection head 9, and a signal processing unit 8.
In the present embodiment, the encoder device 1 will be described with respect to an example of a reflective encoder device that irradiates the scale 6 with modulated irradiation light and receives the reflected light.

  The detection head 9 includes the light source unit 2 and the light receiving unit 7 and is arranged so as to maintain a predetermined distance from the scale 6. At least the light source unit 2 and the light receiving unit 7 of the detection head 9 are integrally supported by a support member of the detection head 9 (in this example, the detection substrate 70).

  The light source unit 2 emits light (modulated light) whose light amount has been modulated by a modulation unit 80 of the signal processing unit 8 described later. The light source unit 2 irradiates the scale 6 with modulated light as shown in FIGS. 2A and 2B. The light source unit 2 includes a first light source unit 21 that emits the first irradiation light L1 and a second light source unit 22 that emits the second irradiation light L2.

The first light source unit 21 is, for example, a light emitting element such as a laser diode that emits laser light, and emits the first irradiation light L <b> 1 whose light amount is modulated by the modulation unit 80.
The second light source unit 22 is, for example, a light emitting element such as a laser diode that emits laser light, and emits the second irradiation light L <b> 2 whose light amount is modulated by the modulation unit 80.
The first irradiation light L <b> 1 and the second irradiation light L <b> 2 are irradiation light whose light amount changes (fluctuates) periodically with respect to time t, and the light amount is modulated by the modulation unit 80 in different phases.
In addition, the 1st light source part 21 and the 2nd light source part 22 are arrange | positioned in the positional relationship which a predetermined | prescribed phase difference produces along a moving direction (X-axis direction). Moreover, the 1st light source part 21 and the 2nd light source part 22 are arrange | positioned on the same surface as the light-receiving surface of the light-receiving part 7, as shown to FIG. 2A-2C. Details of the arrangement of the first light source unit 21 and the second light source unit 22 will be described later.

  The scale 6 is movable relative to the light source unit 2 at least in the moving direction (here, one direction such as the X-axis direction), and the first irradiation light L1 and the second irradiation light L2 are incident thereon. The scale 6 has a pattern 61 (periodic pattern along the X axis) formed along the movement direction (X axis direction). Here, the pattern 61 is, for example, a strip-shaped reflection pattern (a plurality of rectangular reflection patterns having a long axis along the Y axis) with a predetermined pitch (P1) along the moving direction (X axis direction). Are periodically arranged (see FIG. 2A). The scale 6 and the detection head 9 move relatively in the movement direction (X-axis direction).

The light receiving unit 7 is disposed on the detection substrate 70 so as to face the pattern 61 of the scale 6 (see FIGS. 2A and 2B). The light receiving unit 7 includes a plurality of strip-shaped (rectangular) light-receiving elements 71 to 75 arranged at a predetermined pitch (P2) along the moving direction (X-axis direction). The light receiving elements 71 to 75 are connected in parallel. The predetermined pitch (P2) at which the light receiving elements 71 to 75 are arranged is twice the predetermined pitch (P1) of the pattern 61 described above. That is, the light receiving unit 7 includes a plurality of light receiving elements 71 to 75 arranged on the light receiving surface with a pitch width P2 that is twice the pattern 61.
The light receiving unit 7 receives the first irradiation light L1 and the second irradiation light L2, and outputs a light reception signal corresponding to the received first irradiation light L1 and second irradiation light L2.

  The signal processing unit 8 performs light amount modulation processing of the light source unit 2, detects the position of the scale 6 in the movement direction (X-axis direction) based on the light reception signal output from the light receiving unit 7, and detects position information (for example, position x) is output. The signal processing unit 8 includes a modulation unit 80, a drive unit (83, 84), and a synchronous detection circuit unit 85.

The modulation unit 80 periodically modulates the light amount of the first irradiation light L1 and the light amount of the second irradiation light L2. The modulation unit 80 includes modulation signal generation units (81, 82).
The modulation signal generation unit 81 generates a modulation signal (cos ωt) that modulates the light amount of the first irradiation light L1 emitted by the first light source unit 21. This modulation signal (cos ωt) is a signal that periodically fluctuates (changes) with respect to time t, and is a signal that modulates the light amount of the first irradiation light L1 with a cosine wave. The modulation signal generation unit 81 supplies the generated modulation signal (cosωt) to the drive unit 83.
The modulation signal generation unit 82 generates a modulation signal (sin ωt) for modulating the light amount of the second irradiation light L2 emitted by the second light source unit 22. This modulation signal (sin ωt) is a signal that periodically fluctuates (changes) with respect to time t, and is a signal that modulates the light amount of the second irradiation light L2 with a sine wave. The modulation signal generation unit 82 supplies the generated modulation signal (sin ωt) to the drive unit 84 and the synchronous detection circuit unit 85.

  That is, the modulation unit 80 modulates the light amount of the first irradiation light L1 with a cosine wave, and modulates the light amount of the second irradiation light L2 with a sine wave. As an example, the modulation unit 80 modulates the first irradiation light L1 (the light amount) and the second irradiation light L2 (the light amount) with phases different from each other.

The drive unit 83 varies (changes) the current supplied to the first light source unit 21 according to the modulation signal (cosωt) supplied from the modulation signal generation unit 81 of the modulation unit 80. When the current supplied to the first light source unit 21 varies (changes), the first light source unit 21 varies (changes) the light amount of the first irradiation light L1 in accordance with the variation (change) of the current.
The drive unit 84 varies the current supplied to the second light source unit 22 in accordance with the modulation signal (sin ωt) supplied from the modulation signal generation unit 82 of the modulation unit 80. When the current supplied to the second light source unit 22 fluctuates (changes), the second light source unit 22 fluctuates (changes) the amount of the second irradiation light L2 in accordance with the fluctuation (change) of the current.

  The synchronous detection circuit unit 85 (position detection unit) detects the position x of the scale 6 in the movement direction (X-axis direction) based on the light reception signal (sin (ωt + x)) output from the light reception unit 7. The synchronous detection circuit unit 85 uses, for example, a synchronous detection method based on the light reception signal (sin (ωt + x)) and the modulation signal (sinωt) that modulates the light amount of the second light source unit 22. The position x is detected. The synchronous detection circuit unit 85 outputs the detected position x of the scale 6. The principle of generating the light reception signal (sin (ωt + x)) output from the light receiving unit 7 will be described later.

Next, the arrangement of the first light source unit 21 and the second light source unit 22 of the light source unit 2 in the present embodiment will be described.
As shown in FIGS. 2A to 2C, the first light source unit 21 and the second light source unit 22 are spaced by a predetermined distance ΔD1 in the movement direction (X-axis direction) on the same plane as the light receiving surface of the light receiving unit 7. Placed in position. The predetermined interval ΔD1 is a quarter interval of the pitch width P2 of the light receiving elements 71 to 75. That is, the first light source unit 21 and the second light source unit 22 are arranged on the same plane as the light receiving surface of the light receiving unit 7 in a positional relationship that is a quarter interval of the pitch width P2 of the light receiving elements 71 to 75. Has been. Here, the pitch width P2 corresponds to one period (360 degrees), and a quarter of the pitch width P2 corresponds to a phase difference of 90 degrees (π / 2).

  By arranging the first light source unit 21 and the second light source unit 22 in such an arrangement relationship, the light receiving unit 7 can have a predetermined phase difference (here, 90 degrees) with respect to the displacement of the position of the scale 6. The first irradiation light L1 and the second irradiation light L2 in which a phase difference between the first and second irradiation lights has occurred are received. That is, the first light source unit 21 and the second light source unit 22 in the light receiving unit 7 have a phase of the first irradiation light L1 and the phase of the second irradiation light L2 with respect to the displacement of the position of the scale 6 is 90 degrees (π ( Pi) / 2) are arranged so as to produce a phase difference.

FIG. 3A and FIG. 3B are diagrams for explaining irradiation light from the first light source unit 21 and the second light source unit 22 in the present embodiment.
FIG. 4 is a diagram illustrating a waveform of a light reception signal by the irradiation light of the first light source unit 21 and the second light source unit 22 in the present embodiment. In this figure, the horizontal axis indicates the position of the scale 6 in the moving direction (X-axis direction), and the vertical axis indicates the received light signal level (voltage) output by the light receiving unit 7 receiving irradiated light.

FIG. 3A shows the first irradiation light L <b> 1 that is the irradiation light of the first light source unit 21. The first light source unit 21 irradiates (emits) the first irradiation light L <b> 1 to the pattern 61 of the scale 6. The first irradiation light L <b> 1 is reflected by the reflection pattern of the pattern 61 and is applied to the light receiving elements 71 to 75 of the light receiving unit 7. The light receiving unit 7 outputs a light reception signal corresponding to the first irradiation light L1.
In FIG. 4, a waveform W1 indicates a light reception signal corresponding to the first irradiation light L1. Since the reflection of the first irradiation light L1 by the pattern 61 varies depending on the position of the scale 6, the received light signal corresponding to the first irradiation light L1 is periodic with respect to the displacement of the position of the scale 6 as indicated by the waveform W1. Fluctuates (changes). Here, the waveform W1 fluctuates (changes) in a sine wave (sin wave) shape. A waveform W1 indicates a light reception signal when the first irradiation light L1 is not modulated in light amount.

On the other hand, FIG. 3B shows the second irradiation light L <b> 2 that is the irradiation light of the second light source unit 22. The second light source unit 22 irradiates (emits) the second irradiation light L <b> 2 to the pattern 61 of the scale 6. The second irradiation light L <b> 2 is reflected by the reflection pattern of the pattern 61 and is applied to the light receiving elements 71 to 75 of the light receiving unit 7. The light receiving unit 7 outputs a light reception signal corresponding to the second irradiation light L2.
In FIG. 4, a waveform W2 indicates a light reception signal corresponding to the second irradiation light L2. Since the reflection of the second irradiation light L2 by the pattern 61 varies depending on the position of the scale 6, the light reception signal corresponding to the second irradiation light L2 is periodic with respect to the displacement of the position of the scale 6 as indicated by the waveform W2. Fluctuates (changes). Here, the waveform W2 fluctuates (changes) in a cosine wave (cos wave) shape. A waveform W2 indicates a light reception signal in the case where the second irradiation light L2 is not modulated in light amount.

  Note that, as described above, the first light source unit 21 and the second light source unit 22 in the light receiving unit 7 are between the phase of the first irradiation light L1 and the phase of the second irradiation light L2 with respect to the displacement of the position of the scale 6. The phase difference is 90 degrees (π / 2). Therefore, the phase difference (Δφ) between the waveform W1 of the light reception signal by the first irradiation light L1 and the waveform W2 of the light reception signal by the second irradiation light L2 is 90 degrees (π / 2).

Next, the operation of the encoder device 1 according to this embodiment and the principle of generating a light reception signal (sin (ωt + x)) will be described.
First, the modulation signal generation unit 81 of the modulation unit 80 generates a modulation signal (cosωt) and supplies it to the drive unit 83. The drive unit 83 varies (changes) the current supplied to the first light source unit 21 in accordance with the modulation signal (cos ωt) supplied from the modulation signal generation unit 81.
Further, the modulation signal generation unit 82 generates a modulation signal (sin ωt) and supplies it to the drive unit 84. The drive unit 84 varies (changes) the current supplied to the second light source unit 22 in accordance with the modulation signal (sin ωt) supplied from the modulation signal generation unit 82.
Thus, the first light source unit 21 and the second light source unit 22 are driven by a sine wave current (or cosine wave current) having the same frequency and a phase shifted by 90 degrees (π / 2).

The first light source unit 21 irradiates (emits) the first irradiation light L <b> 1 modulated by the modulation signal (cosωt) to the pattern 61 of the scale 6. The second light source unit 22 irradiates (emits) the pattern 61 of the scale 6 with the second irradiation light L <b> 2 modulated by the modulation signal (sinωt).
The first irradiation light L <b> 1 and the second irradiation light L <b> 2 are reflected by the pattern 61 of the scale 6 and are applied to the light receiving unit 7.

Here, the light quantity I ₁ of the first irradiation light L ₁ and the light quantity I ₂ of the second irradiation light L 2 in the light receiving unit 7 are expressed by the following relational expression (1).

  Here, the variable x corresponds to the position of the scale 6, the angular frequency ω corresponds to the angular frequency of the light amount modulation, and the variable t corresponds to time.

As shown in Expression (1), the light amount I ₁ of the first irradiation light L ₁ and the light amount I ₂ of the second irradiation light L ₂ change to a cosine function with respect to time t at the same frequency, and Changes to a sine function with respect to the displacement of the position x. Further, as shown in the equation (1), the light amount I ₂ of the second irradiation light L ₂ changes to a sine function with respect to time t at the same frequency, and cosine with respect to the displacement of the position x of the scale 6. Changes to a function. For example, the phase difference between the phase that modulates the light amount I ₁ of the first irradiation light L ₁ and the phase that modulates the light amount I ₂ of the second irradiation light L 2 and the predetermined phase difference with respect to the displacement of the position of the scale 6 are: The same difference value may be used. As an example, the predetermined phase difference (difference value) may be 90 degrees (π / 2).

As described above, the light receiving unit 7 includes the first irradiation light L1 having a cosine wave shape with respect to the time t and a sine wave phase with respect to the position x of the scale 6, and the sine wave shape with respect to the time t and the position of the scale 6. The second irradiation light L2 having a cosine wave phase with respect to x is received, and a received light signal corresponding to the received first irradiation light L1 and second irradiation light L2 is output. That is, the light receiving unit 7 receives the first irradiation light L1 and the second irradiation light L2 having a predetermined phase difference (for example, 90 degrees) and receives the first irradiation light L1 and the second irradiation light L2 received. The light reception signal corresponding to the is output.
The first irradiation light L1 and the second irradiation light L2 are converted into light reception signals in which the light amounts are combined in the light receiving elements 71 to 75 of the light receiving unit 7. The received light signal output from the light receiving unit 7 is expressed by the following equation (2) by combining trigonometric functions.

  For example, the light reception signal (sin (ωt + x)) output from the light receiving unit 7 is a phase modulation signal whose phase changes with the displacement of the position of the scale 6. The synchronous detection circuit unit 85 uses a technique of synchronous phase detection, for example, based on the received light signal (sin (ωt + x)) and the modulation signal (sinωt) that modulates the light amount of the second light source unit 22. The position x is detected.

As described above, the encoder device 1 according to the present embodiment includes the first light source unit 21 from which the light source unit 2 emits the first irradiation light L1 and the second light source unit 22 from which the second irradiation light L2 is emitted. modulation unit 80 modulates the light intensity _{I 2} of the light intensity _{I 1} and the second irradiation light L2 of the first illumination light L1 periodically. The scale 6 is movable relative to the light source unit 2 at least in the movement direction, and is formed along the movement direction (X-axis direction) when the first irradiation light L1 and the second irradiation light L2 enter. Pattern 61 is provided. The light receiving unit 7 receives the first irradiation light L1 and the second irradiation light L2 having a predetermined phase difference (Δφ) with respect to the position x, and receives the first irradiation light L1 and the second irradiation light L2 received. A light reception signal (sin (ωt + x)) corresponding to the above is output. The synchronous detection circuit unit 85 detects the position x of the scale 6 in the movement direction (X-axis direction) based on the light reception signal (sin (ωt + x)).

Thus, the encoder device 1 in this embodiment, at periodic signal modulating unit 80 has a predetermined phase shift the light intensity I ₂ of the light intensity I ₁ and the second irradiation light L2 of the first irradiation light L1 with respect to time t Modulate. The light receiving unit 7 receives the first irradiation light L1 and the second irradiation light L2 having a predetermined phase difference (Δφ) with respect to the position x, and receives the first irradiation light L1 and the second irradiation light L2 received. A light reception signal (for example, sin (ωt + x)) corresponding to is output. Thus, the modulation unit 80 does not need to use a movable part such as an actuator, and can realize a modulation encoder. Further, it is not necessary to adjust a complicated configuration including moving parts. Therefore, the encoder device 1 in the present embodiment can detect the position information with high accuracy.
Further, as described above, the light receiving unit 7 can obtain the light reception signal (sin (ωt + x)) that is a phase modulation signal without using the movable part such as the actuator. Therefore, the encoder apparatus 1 in the present embodiment can simplify the configuration of the modulation encoder. For example, as shown in FIGS. 2A to 2C, a reflective modulation type encoder is realized by a simple configuration of a detection substrate 70 having a light source unit 2 and a light receiving unit 7 and a scale 6 having a reflective pattern 61. can do. That is, the encoder apparatus 1 in this embodiment can detect position information with high accuracy with a simple configuration.

In the present embodiment, the modulation unit 80 modulates the first irradiation light L1 and the second irradiation light L2 with periodic signals having phases different from each other (for example, phases different by 90 degrees) with respect to the time t.
Thus, the light receiving unit 7 can obtain a phase modulation signal whose phase changes as the position of the scale 6 changes as a light receiving signal (for example, sin (ωt + x)). Since a light reception signal including position information can be obtained by a simple means (simple configuration), the encoder device 1 according to the present embodiment can detect the position information with high accuracy by a simple configuration.

In the present embodiment, the phase difference between the phase for modulating the light amount of the first irradiation light L1 and the phase for modulating the light amount of the second irradiation light L2, and a predetermined phase difference (Δφ) relative to the displacement of the position of the scale 6 are used. Is the same difference value (same phase difference). The predetermined phase difference (Δφ) is 90 degrees (π / 2).
As a result, a light reception signal (sin (ωt + x)) that is a phase modulation signal whose phase changes can be obtained. Therefore, the synchronous detection circuit unit 85 uses, for example, a simple technique using a synchronous phase detection technique to 6 positions can be detected. Therefore, the encoder device 1 in the present embodiment can detect the position information with high accuracy with a simple configuration.

In the present embodiment, the first light source unit 21 and the second light source unit 22 are arranged in a positional relationship that causes a predetermined phase difference (Δφ) along the movement direction (X-axis direction).
That is, the phase difference (Δφ) between the first irradiation light L1 and the second irradiation light L2 can be generated according to the positional relationship between the first light source unit 21 and the second light source unit 22. Since there is no need to use a movable part such as an actuator, the encoder device 1 in the present embodiment can detect position information with high accuracy with a simple configuration.

In the present embodiment, the light receiving unit 7 includes a plurality of light receiving elements 71 to 75 arranged on the light receiving surface with a pitch width P2 that is twice the pattern 61. The 1st light source part 21 and the 2nd light source part 22 are arrange | positioned in the positional relationship which becomes the space | interval of 1/4 of the pitch width P2 of the light receiving elements 71-75 on the same surface as a light-receiving surface.
Thereby, the encoder device 1 according to the present embodiment has a simple configuration, and the first irradiation light L1 and the second irradiation light L2 with respect to the displacement of the position of the scale 6 have a predetermined phase difference (Δφ) of 90 degrees (π / 2). ) Can be set. Therefore, the encoder device 1 in the present embodiment can detect the position information with high accuracy with a simple configuration.

Moreover, in this embodiment, the modulation | alteration part 80 modulates the light quantity of the 1st irradiation light L1 with a cosine wave, and modulates the light quantity of the 2nd irradiation light L2 with a sine wave. The light receiving unit 7 receives the first irradiation light L1 having a sinusoidal phase and the second irradiation light L2 having a cosine wave phase. The synchronous detection circuit unit 85 detects the position of the scale 6 based on the light reception signal (sin (ωt + x)) and the modulation signal (sinωt) that modulates the light amount of the second light source unit 22.
Thereby, the encoder apparatus 1 in this embodiment can detect position information with high accuracy with a simple configuration.

[Second Embodiment]
FIG. 5 is a schematic block diagram showing the configuration of the encoder device 1a according to the second embodiment. 5, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.
In the present embodiment, the configuration of the detection head 9 and the scale 6 of the encoder device 1a is the configuration shown in FIGS. 2A-2C, as in the first embodiment.

  The encoder device 1a is an optical type that detects position information (for example, the moving direction, moving amount, or displacement of the scale 6) of the scale 6 that moves in a predetermined moving direction (for example, one direction such as the X-axis direction). It is a linear encoder. The encoder device 1a includes a scale 6, a detection head 9, and a signal processing unit 8a.

  The signal processing unit 8a performs light amount modulation processing of the light source unit 2, detects the position of the scale 6 in the moving direction (X-axis direction) based on the light reception signal output from the light receiving unit 7, and detects position information (eg, position x) is output. The signal processing unit 8a includes a modulation unit 80a, a drive unit (83, 84), and a decoder circuit unit 85a. The signal processing unit 8a in the present embodiment is different from the signal processing unit 8 in the first embodiment in the processing of the modulation unit 80a and the decoder circuit unit 85a. As an example, the signal processing unit 8 a is different from the signal processing unit 8 in the first embodiment in the light amount modulation processing of the light source unit 2 and the position detection processing of the scale 6.

The modulator 80a periodically modulates the light amount of the first irradiation light L1 and the light amount of the second irradiation light L2. The modulation unit 80a includes a modulation signal generation unit 82a, a sine conversion unit 86, and a cosine conversion unit 87.
The modulation signal generation unit 82a generates a modulation signal (rsin ωt) used for light amount modulation of the first irradiation light L1 and the second irradiation light L2. Here, the constant r is a constant representing the amplitude of the modulation signal. This modulation signal (rsinωt) is a signal that periodically fluctuates (changes) with respect to time t. The modulation signal generation unit 82 a supplies the generated modulation signal (rsinωt) to the sine conversion unit 86, cosine conversion unit 87, and synchronous detection circuit unit 85.

  Based on the modulation signal (rsin ωt) supplied from the modulation signal generation unit 82a, the sine conversion unit 86 performs a light amount modulation signal (sin (rsin ωt)) for modulating the light amount of the first irradiation light L1 emitted by the first light source unit 21. Is generated. For example, the sine conversion unit 86 converts the modulation signal (rsinωt) based on a conversion table of a sine function, and generates a light amount modulation signal (sin (rsinωt)). The sine conversion unit 86 supplies the generated light amount modulation signal (sin (rsinωt)) to the drive unit 83.

  The cosine transform unit 87 is a light amount modulation signal (cos (rsin ωt)) for modulating the light amount of the second irradiation light L2 emitted by the second light source unit 22 based on the modulation signal (rsin ωt) supplied from the modulation signal generation unit 82a. Is generated. For example, the cosine conversion unit 87 converts the modulation signal (rsin ωt) based on the conversion table of the cosine function to generate a light amount modulation signal (cos (rsin ωt)). The cosine conversion unit 87 supplies the generated light amount modulation signal (cos (rsinωt)) to the drive unit 84.

  The drive unit 83 and the drive unit 84 are the same as those in the first embodiment except that the supplied modulation signals are different. The drive unit 83 varies (changes) the current supplied to the first light source unit 21 in accordance with the light amount modulation signal (sin (rsinωt)) supplied from the sine conversion unit 86 of the modulation unit 80. Further, the drive unit 84 varies the current supplied to the second light source unit 22 in accordance with the light amount modulation signal (cos (rsinωt)) supplied from the cosine conversion unit 87 of the modulation unit 80.

  As described above, the modulation unit 80a modulates the light amount of the first irradiation light L1 based on the signal (sin (rsinωt)) obtained by modulating the modulation signal (rsinωt) periodically changed by the sine wave by the sine function. The modulation unit 80a modulates the light amount of the second irradiation light L2 based on a signal (cos (rsinωt)) obtained by modulating the modulation signal (rsinωt) with a cosine function.

  The decoder circuit unit 85a (position detection unit) detects the position x of the scale 6 in the movement direction (X-axis direction) based on the light reception signal (cos (rsinωt + x)) output from the light reception unit 7. That is, the decoder circuit unit 85a detects the position x of the scale 6 based on the light reception signal (cos (rsinωt + x)) and the modulation signal (rsinωt) generated by the modulation signal generation unit 82a. Here, as a method of detecting position information by the decoder circuit unit 85a, for example, a signal processing method described in “US Pat. No. 6,639,686” of Patent Document 1 can be used. The decoder circuit unit 85a outputs the detected position x of the scale 6.

  Next, the operation of the encoder device 1a in this embodiment and the principle of generating a light reception signal (cos (rsinωt + x)) will be described.

FIG. 6 is a diagram illustrating waveforms of the light amount modulation signal and the light reception signal in the present embodiment. In this figure, the horizontal axis indicates time t, and the vertical axis indicates the position level (voltage) of each signal.
FIG. 6A shows a waveform W3 of the light intensity modulation signal (sin (rsinωt)) of the first light source unit 21 generated by the sine conversion unit 86. FIG. 6B shows a waveform W4 of the light amount modulation signal (cos (rsinωt)) of the second light source unit 22 generated by the cosine conversion unit 87.
FIG. 6C shows a waveform W5 of a light reception signal (cos (rsinωt + x)) in which the light receiving unit 7 receives the first irradiation light L1 and the second irradiation light L2.

In the encoder device 1a, first, the modulation signal generation unit 82a and the sine conversion unit 86 of the modulation unit 80a generate a light amount modulation signal (sin (rsinωt)) like the waveform W3 and supply it to the drive unit 83. The drive unit 83 varies (changes) the current supplied to the first light source unit 21 in accordance with the light intensity modulation signal (sin (rsinωt)) supplied from the sine conversion unit 86.
In addition, the modulation signal generation unit 82 a and the cosine conversion unit 87 generate a light amount modulation signal (cos (rsinωt)) like the waveform W <b> 4 and supply it to the drive unit 84. The drive unit 84 varies (changes) the current supplied to the second light source unit 22 in accordance with the light intensity modulation signal (cos (rsinωt)) supplied from the cosine conversion unit 87.
As described above, the first light source unit 21 and the second light source unit 22 are driven by a sine wave current (or cosine wave current) whose phase is shifted by 90 degrees (π / 2).

The first light source unit 21 irradiates (emits) the pattern 61 of the scale 6 with the first irradiation light L <b> 1 modulated by the light amount modulation signal (sin (rsinωt)). In addition, the second light source unit 22 irradiates (emits) the pattern 61 of the scale 6 with the second irradiation light L <b> 2 modulated by the light amount modulation signal (cos (rsinωt)).
The first irradiation light L <b> 1 and the second irradiation light L <b> 2 are reflected by the pattern 61 of the scale 6 and are applied to the light receiving unit 7.

Here, in the light receiving section 7, the light amount I ₂ of light quantity I ₁ and the second irradiation light L2 of the first illumination light L1 is expressed in relation of the following equation (3).

  Here, the constant r corresponds to the amplitude of the modulation signal, the variable x corresponds to the position of the scale 6, the angular frequency ω corresponds to the angular frequency of the light amount modulation, and the variable t corresponds to time.

As shown in Equation (3), the light amount I ₁ of the first irradiation light L ₁ and the light amount I ₂ of the second irradiation light L ₂ periodically change with respect to time t at the same frequency, and It changes periodically with respect to the displacement of the position x. For example, the phase difference between the phase that modulates the light amount I ₁ of the first irradiation light L ₁ and the phase that modulates the light amount I ₂ of the second irradiation light L 2 and the predetermined phase difference with respect to the displacement of the position of the scale 6 are: The same difference value may be used. Further, for example, the predetermined phase difference (difference value) may be 90 degrees (π / 2).

As described above, the light receiving unit 7 includes the first irradiation light L1 having a sinusoidal phase with respect to the position x of the scale 6, and the second irradiation light L2 having a cosine wave phase with respect to the position x of the scale 6. , And a light reception signal corresponding to the received first irradiation light L1 and second irradiation light L2 is output. That is, the light receiving unit 7 receives the first irradiation light L1 and the second irradiation light L2 having a predetermined phase difference (for example, 90 degrees) and receives the first irradiation light L1 and the second irradiation light L2 received. A light reception signal (waveform W5 in FIG. 6 (c)) corresponding to is output.
The first irradiation light L1 and the second irradiation light L2 are converted into light reception signals in which the light amounts are combined in the light receiving elements 71 to 75 of the light receiving unit 7. The light receiving signal output from the light receiving unit 7 is expressed by the following equation (4) by combining trigonometric functions.

  The light reception signal (cos (rsin ωt + x)) represented by the equation (4) has the same format as the signal used for the modulation encoder described in the above-mentioned Patent Document 1. By using the signal processing method described in “US Pat. No. 6,639,686” of Patent Document 1, the decoder circuit unit 85a uses the light reception signal (cos (rsinωt + x)) and the modulation signal generation unit 82a. The position x of the scale 6 is detected based on the modulation signal (rsin ωt) generated by. The decoder circuit unit 85a outputs the detected position x of the scale 6.

As described above, the encoder device 1a according to the present embodiment includes the first light source unit 21 from which the light source unit 2 emits the first irradiation light L1 and the second light source unit 22 from which the second irradiation light L2 is emitted. modulation section 80a modulates the light intensity _{I 2} of the light intensity _{I 1} and the second irradiation light L2 of the first illumination light L1 periodically. The light receiving unit 7 receives the first irradiation light L1 and the second irradiation light L2 having a predetermined phase difference (Δφ) from each other, and receives light signals corresponding to the received first irradiation light L1 and second irradiation light L2. (Cos (rsinωt + x)) is output. The decoder circuit unit 85a detects the position x of the scale 6 in the movement direction (X-axis direction) based on the light reception signal (cos (rsinωt + x)).

  As described above, in the encoder device 1a according to the present embodiment, like the encoder device 1 according to the first embodiment, the modulation unit 80a does not need to use a movable part such as an actuator, and can realize a modulation type encoder. it can. Therefore, the encoder device 1a in the present embodiment can detect the position information with high accuracy in the same manner as the encoder device 1 in the first embodiment.

In the present embodiment, the predetermined phase difference (Δφ) with respect to the displacement of the position of the scale 6 is 90 degrees (π / 2). For example, the phase difference between the phase that modulates the light amount of the first irradiation light L1 and the phase that modulates the light amount of the second irradiation light L2, and the predetermined phase difference (Δφ) with respect to the displacement of the position of the scale 6 are: The same difference value (the same phase difference) may be used.
As a result, a received light signal (cos (rsinωt + x)) that is a phase-modulated signal whose phase changes can be obtained, so that the decoder circuit unit 85a uses, for example, a simple method using a modulation-type encoder to generate a scale 6 Can be detected. Therefore, the encoder device 1a in the present embodiment can detect the position information with high accuracy with a simple configuration.

In the present embodiment, the modulation unit 80a calculates the light amount of the first irradiation light L1 based on a signal (sin (rsin ωt)) obtained by modulating a modulation signal (rsin ωt) periodically changed by a sine wave with a sine function. Modulate. The modulation unit 80a modulates the light amount of the second irradiation light L2 based on a signal (cos (rsinωt)) obtained by modulating the modulation signal (rsinωt) with a cosine function. The light receiving unit 7 receives the first irradiation light L1 having a sinusoidal phase and the second irradiation light L2 having a cosine wave phase. The decoder circuit unit 85a detects the position of the scale 6 based on the light reception signal (cos (rsinωt + x)) and the modulation signal (rsinωt).
Thereby, the encoder apparatus 1a in this embodiment can detect position information with high accuracy with a simple configuration.

In each of the above embodiments, a predetermined phase difference (Δφ) between the first irradiation light L1 and the second irradiation light L2 in the light receiving unit 7 is generated by the arrangement of the first light source unit 21 and the second light source unit 22. However, it is also possible to generate a predetermined phase difference (Δφ) by another method.
Next, a modified example for generating the predetermined phase difference (Δφ) will be described.

<First Modification>
In the first modification, the above-described predetermined phase difference (Δφ) is generated using the glass block 4 that is an optical member.
FIG. 7 is a schematic diagram showing the configuration of the detection head 9 and the scale 6 in the first modification. In FIG. 7, the same components as those in FIGS. 2A-2C are denoted by the same reference numerals, and the description thereof is omitted.
In FIG. 7, the detection head 9 includes a light source unit 2, a collimator lens 3, a glass block 4, an index grating 5, mirrors (41 and 42), and a light receiving unit 7.
Here, each component of the detection head 9 is integrally supported by a support member (not shown) of the detection head 9. That is, each configuration of the detection head 9 is fixedly arranged in a predetermined positional relationship.

The light source unit 2 includes a first light source unit 21 that emits the first irradiation light L1 and a second light source unit 22 that emits the second irradiation light L2. Here, the 1st light source part 21 and the 2nd light source part 22 are arrange | positioned in the same position (substantially same position is included). Further, the first light source unit 21 and the second light source unit 22 emit light with different wavelengths of the wavelength λ ₁ and the wavelength λ ₂ , respectively. That is, the second light source unit 22 emits the second irradiation light L2 having a wavelength different from that of the first irradiation light L1.

The collimator lens 3 receives the modulated light emitted from the light source unit 2 and deflects it into parallel light in the Y-axis direction. The collimator lens 3 irradiates the glass block 4 and the index grating 5 with the deflected parallel light. Incidentally, the modulated light transmitted through the collimator lens 3, the Apacha (not shown), is divided into a light beam E _A and the light beam E _B. The collimator lens 3, a light beam E _A of the modulated light is irradiated to the index grating 5, through the glass block 4 is irradiated with light beams E _B in the index grating 5. That is, the collimator lens 3 is incident on the index grating 5 the glass block 4 passes (transparent) is not only the light beam E _B.
Here, the optical path reaching the light receiving portion 7 by the light beam E _A light source unit 2 and the first optical path LL1 between the light receiving portion 7, the optical path reaching the light receiving portion 7 by the light beam E _B light source unit 2 receiving The second optical path LL2 between the unit 7 will be described below.

Glass block 4 (optical member) is disposed, for example, a position on which a light beam E _B passing between the collimator lens 3 and the index grating 5, and transmits the emitted light beam E _B from the collimator lens 3. That is, the glass block 4 includes the first optical path LL1 and the second optical path LL2 among the optical paths of the first irradiation light L1 and the second irradiation light L2 obtained by dividing the first irradiation light L1 and the second irradiation light L2 into different optical paths. Are arranged in at least one of the optical paths. The first optical path LL1 and the second optical path LL2 are optical paths of the first irradiation light L1 and the second irradiation light L2, and the glass block 4 is disposed in at least one of the optical paths (or both optical paths). It is an optical path. The glass block 4 has a predetermined refractive index _Ng, and has a predetermined thickness D in the traveling direction of the light irradiated from the collimator lens 3. Thus, the glass block 4, and the difference in refractive index between the refractive index N _a of the air, by a difference in wavelength between the first light source part 21 and the second light source unit 22, the first irradiation light L1 and the second illumination A predetermined phase difference (Δφ) with respect to the displacement of the position of the scale 6 of the light L2 is generated. In addition, what is necessary is just to mutually change the thickness D and refractive index of the glass block 4 arrange | positioned in a mutual optical path, when arrange | positioning the glass block 4 in both the optical path of 1st optical path LL1 and 2nd optical path LL2.

As an example, the glass block 4 includes the first light path LL1 between the light source unit 2 and the light receiving unit 7 obtained by dividing the first irradiation light L1 and the second irradiation light L2 into different optical paths, the light source unit 2, and the light receiving unit 7. Is disposed in at least one of the optical paths with respect to the second optical path LL2, and a predetermined phase difference (Δφ) is generated. The thickness D of the direction of the glass block 4 first irradiation light L1 and the second illumination light L2 is transmitted has a wavelength lambda ₁ of the first illumination light L1, and the wavelength lambda ₂ of the second illumination light L2, glass It is determined on the basis of the refractive index N _g of the block 4. Details of the thickness D of the glass block 4 will be described later.

  The index grating 5 is, for example, a diffraction grating in which a grating-like pattern is formed, and has a diffraction pattern (grating pattern having a period along the X axis) that is periodically formed along the X axis direction. Type diffraction grating. The index grating 5 is disposed between the collimator lens 3 and the scale 6, generates diffracted light based on incident light, and irradiates the mirrors (41, 42) with the generated diffracted light.

The mirrors (41, 42) deflect the diffracted light of the first optical path LL 1 and the diffracted light of the second optical path LL 2 generated by the index grating 5, respectively, and enter the same position on the scale 6. In other words, the mirror 41 deflects the light beam E _A that has passed through the index grating 5 is incident on the pattern 61 of the scale 6. The mirror 42 deflects the light beam E _B that have passed through the index grating 5 is incident on the pattern 61 of the scale 6.

The scale 6 has a pattern 61 as shown in FIGS. 2A-2C, reflects the diffracted light deflected by the mirrors (41, 42), and makes interference light enter the light receiving unit 7.
The light receiving unit 7 receives the first irradiation light L1 and the second irradiation light L2 that have arrived from the light source unit 2 through the first optical path LL1 and the second optical path LL2, and receives the received first irradiation light L1 and second light. A light reception signal corresponding to the irradiation light L2 is output. Here, the 1st irradiation light L1 and the 2nd irradiation light L2 which the light-receiving part 7 light-receives become the interference light which reached | attained via the 1st optical path LL1 and the 2nd optical path LL2.

Next, the principle of causing a predetermined phase difference (Δφ) in the present modification and the thickness D of the glass block 4 will be described.
As described above, when the glass block 4 is disposed between the second optical path LL2, the phase delay of light beams E _B for light beam E _A (E _B phase delay phi) occurs. The phase lag (E _B phase delay phi) is expressed by the following equation (5).

Here, the variable λ corresponds to the emission wavelength, the constant N _a corresponds to the refractive index of air, the constant N _g corresponds to the refractive index of glass, and the variable D corresponds to the thickness of the glass block 4.
Further, when the light beam E _A and the light beam E _B diffracted by the index grating 5 and the scale 6 are expressed by complex amplitude, they are expressed as Expression (6).

Here, the variable L is the optical path length is an optical path length when the optical path length from the index grating 5 to the scale 6 is equal with the light beam E _A and the light beam E _B. The variable A corresponds to the amplitude width, the variable x corresponds to the position of the scale 6, and the variable P corresponds to the pitch width of the index lattice 5 and the scale 6.
Further, the light intensity I obtained by interference between light beams E _A and the light beam E _B which is received by the light receiving unit 7 is expressed as Equation (7).

Here, the E _B phase delay phi ₁ when the first light source part 21 is on, the second light source unit 22 is to E _B phase delay phi ₂ when lit, the difference E _B phase delay (Φ ₁ −φ ₂ ) is represented by the following formula (8). As shown in the above equation (7), the phase delay in the interference light between the light beam E _A and the light beam E _B is twice the value (2φ) of the E _B phase delay φ. Therefore, when the first illumination light L1 predetermined phase difference between the second illumination light L2 a ([Delta] [phi) to 90 degrees ([pi / 2), the _{E B} phase delay difference a (φ ₁ -φ ₂₎ (π / 4).

The above equation (7), the light intensity I ₁ of the interference light by the first irradiation light L1 of the first light source unit 21 is expressed as the following equation (9).

Further, according to the above formulas (7) and (8), the light intensity I ₂ of the interference light by the second irradiation light L2 of the second light source unit 22 is expressed as the following formula (10).

As shown in the equations (9) and (10), the light intensity I ₁ and the light intensity I ₁ periodically fluctuate (change) with respect to the displacement of the position x of the scale 6. Here, the light intensity I ₁ corresponds to the light reception signal received by the light receiving unit 7 according to the first irradiation light L1, and the light intensity I ₂ corresponds to the light reception signal received by the light receiving unit 7 according to the first irradiation light L2. Correspond. That is, the light reception signal by the first irradiation light L <b> 1 periodically varies (changes) with respect to the displacement of the position x of the scale 6. Here, the light reception signal by the first irradiation light L1 fluctuates (changes) in a sine wave (sin wave) shape. Further, the light reception signal by the second irradiation light L2 periodically varies (changes) with respect to the displacement of the position x of the scale 6. Here, the light reception signal by the second irradiation light L2 fluctuates (changes) in a cosine wave (cos wave) shape.

Thus, by setting the thickness D of the glass block 4, the wavelength λ ₁ of the first irradiation light L _1, and the wavelength λ ₂ of the second irradiation light L 2 so as to satisfy the above formula (8). The predetermined phase difference (Δφ) between the first irradiation light L1 and the second irradiation light L2 can be set to 90 degrees (π / 2).

  In addition, said Formula (9) and Formula (10) are applied to Formula (1) in 1st Embodiment, or Formula (3) in 2nd Embodiment instead of (sinx) and (cosx). be able to. Thereby, the position of the scale 6 can be detected as in the first embodiment or the second embodiment.

As described above, in the first modification, the glass block 4 includes the first optical path LL1 between the light source unit 2 and the light receiving unit 7 in which the first irradiation light L1 and the second irradiation light L2 are divided into different optical paths. And at least one of the second optical path LL2 between the light source unit 2 and the light receiving unit 7 to generate a predetermined phase difference (Δφ).
Thereby, since it is not necessary to use movable parts, such as an actuator, the encoder apparatus 1 (or 1a) in a 1st modification can detect position information with high precision by a simple structure.

The thickness D of the direction of the glass block 4 first irradiation light L1 and the second illumination light L2 is transmitted has a wavelength lambda ₁ of the first illumination light L1, and the wavelength lambda ₂ of the second illumination light L2, glass It is determined on the basis of the refractive index N _g of the block 4.
Thereby, the predetermined phase difference (Δφ) between the first irradiation light L1 and the second irradiation light L2 can be set to an arbitrary value depending on the thickness D of the glass block 4.

<Second Modification>
In the second modification, the above-described predetermined phase difference (Δφ) is generated using the index pattern (51, 52) of the index grating 5.
FIGS. 8A, 8B, and 8C are schematic views showing the configurations of the detection head 9 and the scale 6 in the second modification. 8A-8C, the movement direction of the scale 6 will be described below as the X-axis direction, and the irradiation direction of the light source unit 2 will be described as the positive direction of the Y-axis.
Here, FIG. 8A is a diagram (a diagram in a direction along the Z axis) illustrating the case where the detection head 9 and the scale 6 are viewed from the Z axis direction. FIG. 8B is a diagram (a diagram in a direction along the X axis) showing the detection head 9 and the scale 6 viewed from the X axis direction. FIG. 8C is a diagram (a diagram in the direction along the Y axis) showing the index grating 5 viewed from the light source unit 2 side (from the Y axis direction).
8A-8C, the same components as those in FIGS. 2A-2C and FIG. 7 are denoted by the same reference numerals, and the description thereof is omitted.

8A-8C, the detection head 9 includes a light source unit 2, a collimator lens (31, 32), an index grating 5, and a light receiving unit 7.
Here, each component of the detection head 9 is integrally supported by a support member (not shown) of the detection head 9. That is, each configuration of the detection head 9 is fixedly arranged in a predetermined positional relationship.

  The light source unit 2 includes a first light source unit 21 that emits the first irradiation light L1 and a second light source unit 22 that emits the second irradiation light L2. Here, the first light source unit 21 and the second light source unit 22 are arranged at positions corresponding to the index patterns (51, 52) of the index lattice 5. Further, the first light source unit 21 and the second light source unit 22 emit light with the same wavelength unlike the first modification.

The collimator lens 31 receives the first irradiation light L1 emitted from the first light source unit 21 and deflects it into parallel light in the Y-axis direction. The collimator lens 31 irradiates the index pattern 51 of the index grating 5 with the deflected parallel light.
The collimator lens 32 receives the second irradiation light L2 emitted from the second light source unit 22 and deflects it into parallel light in the Y-axis direction. The collimator lens 32 irradiates the index pattern 52 of the index grating 5 with the deflected parallel light.

The index grating 5 is, for example, a diffraction grating in which a lattice-like pattern is formed, and is an index that is a diffraction pattern (grating pattern having a period along the X axis) periodically formed along the X axis direction. It has a pattern (51, 52). The index grating 5 is disposed between the collimator lens (31, 32) and the scale 6, generates diffracted light based on the incident light, and irradiates the scale 6 with the generated diffracted light.
As shown in FIG. 8C, the index pattern 51 and the index pattern 52 are formed (arranged) by shifting the position of the diffraction pattern by a predetermined distance ΔD2 along the moving direction (X-axis direction) of the scale 6. Yes. This predetermined interval ΔD2 is a value of a quarter of the pitch width P3 of the diffraction pattern. That is, the index pattern 51 and the index pattern 52 are shifted from each other by the predetermined distance ΔD2, thereby generating the predetermined phase difference (Δφ). When the predetermined interval ΔD2 is a value that is a quarter of the pitch width P3 of the diffraction pattern, the predetermined phase difference (Δφ) is 90 degrees (π / 2).

  The scale 6 in the second modification is a transmissive scale, and transmits the first irradiation light L1 and the second irradiation light L2 to irradiate the light receiving unit 7.

As described above, in the second modification, the index patterns (51, 52) of the index lattice 5 are arranged by shifting the arrangement along the moving direction (X-axis direction) of the scale 6 by a predetermined interval ΔD2. A predetermined phase difference (Δφ) is generated.
Thereby, since it is not necessary to use movable parts, such as an actuator, the encoder apparatus 1 (or 1a) in a 1st modification can detect position information with high precision by a simple structure.

[Third Embodiment]
Next, an embodiment in which the encoder device 1 (1a) in each of the above embodiments is applied to a drive device will be described.
FIG. 9 is a schematic block diagram showing the configuration of the driving apparatus 100 in the present embodiment.
The present embodiment is a drive device 100 that drives a moving body using the encoder device 1 (1a) in each of the above embodiments. In the present embodiment, a stage apparatus that drives the stage 10 as an example of a moving body will be described.

In FIG. 9, a drive device 100 (device) that is a stage device includes an encoder device 1 (1 a), a stage 10, a drive unit 11, and a control unit 12. 9, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.
The encoder device 1 (1a) includes a scale 6, a detection head 9, and a signal processing unit 8 (8a).

The stage 10 (moving body) is fixed to, for example, the scale 6 or the detection head 9 and is driven (moved) by the driving unit 11. That is, the stage 10 is connected to the scale 6 or the detection head 9.
The drive unit 11 relatively drives the stage 10 in the position detection direction on the scale 6.
The control unit 12 is connected to the signal processing unit 8 (8a) of the encoder device 1 (1a) via the control signal line C1. The encoder device 1 (1a) supplies the above-described position information to the control unit 12 via the control signal line C1.
The control unit 12 is connected to the drive unit 11 via the control signal line C2. The control unit 12 controls the drive unit 11 via the control signal line C2.

  The control unit 12 controls the drive unit 11 based on the position information of the stage 10 supplied from the encoder device 1 (1a).

As described above, the driving device 100 according to the present embodiment includes the encoder device 1 (1 a) and the stage 10 connected to the scale 6 or the detection head 9.
Since the encoder device 1 (1a) can detect the position information of the scale 6 with high accuracy, the driving device 100 according to the present embodiment can detect the position information of the stage 10 with high accuracy. Thereby, the drive device 100 in the present embodiment can control the position of the stage 10 with high accuracy.

  The present invention is not limited to the above embodiments, and can be modified without departing from the spirit of the present invention.

  In each of the embodiments described above, the mode in which the predetermined phase difference (Δφ) between the first irradiation light L1 and the second irradiation light L2 is 90 degrees (π / 2) has been described, but other values are used. Form may be sufficient.

  In the first and second embodiments described above, the embodiment in which the reflective scale is used for the scale 6 has been described. In another embodiment, a transmission type encoder apparatus having a configuration in which a transmission type scale is used for the scale 6 as in the second modification can be applied. Note that examples of the transmissive scale include a scale having a transmissive diffraction grating and a scale having a slit (shadow) pattern. Alternatively, in the form according to the second modification, a reflective encoder device such as a form using a reflective scale as the scale 6 can be applied.

  In each of the above embodiments, the predetermined phase difference (Δφ) with respect to the displacement of the position of the scale 6 can be other than 90 degrees. For example, when a general Δφ is used, the received light signal is as shown in Expression (11), and the phase component does not directly represent the position x of the scale 6. However, in order to calculate the position x of the scale 6, the position x of the scale 6 can be obtained by inversely transforming the phase component obtained from the equation (11) from the synchronous detection result using a conversion table or the like. .

  When the modulation waveforms of the first irradiation light L1 and the second irradiation light L2 have a phase difference other than 90 degrees instead of the relationship between the cosine wave and the sine wave, the light reception signal obtained is ωt in Expression (11). And x are replaced. Therefore, the position x of the scale 6 can be obtained by performing inverse transformation on the obtained phase component.

  In the second embodiment, the sine conversion unit 86 and the cosine conversion unit 87 have been described as generating the light amount modulation signal using the conversion table. However, the light amount modulation signal is generated using another method. The form to do may be sufficient. For example, the sine conversion unit 86 and the cosine conversion unit 87 may generate the light amount modulation signal by arithmetic processing.

Further, in each of the embodiments described above, the detection head 9 has been described as not including the signal processing unit 8 (8a). However, the detection head 9 may include the signal processing unit 8 (8a).
In each of the above embodiments, the scale 6 is a linear scale. However, the scale 6 may be applied to a rotary encoder using a disk-type or fan-shaped scale 6.

  In each of the above embodiments, the detection head 9 is fixed and the scale 6 moves in the displacement direction. However, the scale 6 may be fixed and the head unit 9 may move in the displacement direction.

  Further, in the third embodiment, the form in which the encoder apparatus 1 (1a) is applied to the driving apparatus 100 that drives the stage 10 in the moving direction (eg, one direction) has been described. However, the present invention is limited to this form. It is not a thing. For example, the present invention may be applied to devices such as an XY moving stage, a three-dimensional measuring device, a motor device, a machine tool, a precision machine, a semiconductor chip mounter, and a stepper device.

  DESCRIPTION OF SYMBOLS 1, 1a ... Encoder apparatus, 2 ... Light source part, 4 ... Glass block, 6 ... Scale, 7 ... Light-receiving part, 9 ... Detection head, 10 ... Stage, 21 ... 1st light source part, 22 ... 2nd light source part, 61 ... Pattern, 71, 72, 73, 74, 75 ... Light receiving element, 80, 80a ... Modulation unit, 85 ... Synchronous detection circuit unit, 85a ... Decoder circuit unit, 100 ... Driving device

Claims (6)

A light source unit having a first light source unit that emits first irradiation light and a second light source unit that emits second irradiation light;
A modulation unit that periodically modulates the light amount of the first irradiation light and the light amount of the second irradiation light with mutually different phases;
A scale having a pattern that is movable at least in the movement direction relative to the light source unit, the first irradiation light and the second irradiation light are incident, and is formed along the movement direction;
A light receiving unit that receives the first irradiation light and the second irradiation light that have a predetermined phase difference from each other and outputs a light reception signal corresponding to the received first irradiation light and the second irradiation light;
A position detection unit that detects a position of the scale in the moving direction based on the light reception signal,
The second light source unit emits the second irradiation light having a wavelength different from that of the first irradiation light,
Arranged in at least one of the first optical path and the second optical path among the optical paths of the first irradiation light and the second irradiation light between the light source unit and the light receiving unit, and the predetermined phase difference An optical member for generating
Encoder apparatus. The thickness in the direction in which the first irradiation light and the second irradiation light are transmitted through the optical member is:
It is determined based on the wavelength of the first irradiation light, the wavelength of the second irradiation light, and the refractive index of the optical member.
The encoder apparatus according to 請 Motomeko 1. The predetermined phase difference is 90 degrees.
The encoder apparatus according to 請 Motomeko 1 or claim 2. The modulation unit modulates the light amount of the first irradiation light with a cosine wave, modulates the light amount of the second irradiation light with a sine wave,
The light receiving unit receives the first irradiation light having a sinusoidal phase and the second irradiation light having a cosine wave phase,
The position detection unit detects a position of the scale based on the light reception signal and a modulation signal that modulates a light amount of the second light source unit.
The encoder apparatus according to any one of claims 3 to 請 Motomeko 1. The modulation unit modulates the light amount of the first irradiation light based on a signal obtained by modulating a modulation signal periodically changed by a sine wave by a sine function, and based on a signal obtained by modulating the modulation signal by a cosine function. Modulating the amount of the second irradiation light,
The light receiving unit receives the first irradiation light having a sinusoidal phase and the second irradiation light having a cosine wave phase,
The position detection unit detects the position of the scale based on the light reception signal and the modulation signal.
The encoder apparatus according to any one of claims 4 to 請 Motomeko 1. An encoder device according to any one of claims 1 to 5 ,
A moving body connected to the detection head of the scale or the encoder device;
Apparatus comprising: a.

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