JP2013029405A - Position measurement device, method of manufacturing workpiece using the same, and molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position measurement device that can take a measurement even when a work distance varies, and have higher resolution.SOLUTION: A scale part 30 is so configured that first and second reflection surfaces 31 and 32 periodically vary in relative distance, and a light receiving sensor 14 measures light intensity of interference light formed with light reflected by the first and second reflection surfaces 31 and 32. Periodic variation in light intensity of the interference light is computed by an arithmetic unit 20 into position information to measure the position of a measurement object in spite of variation in work distance.

Description

  The present invention relates to a position measurement device that measures the position of a movable object such as a stage.

  Generally, in a machine tool such as a multi-axis machine, a stage on which a workpiece is placed is provided so as to be movable in a plurality of directions. Such a stage having a plurality of degrees of freedom is usually provided with an optical linear encoder for each degree of freedom, and its position is measured.

  However, if a linear encoder is provided for each degree of freedom as described above, it is necessary to combine a plurality of linear encoders in order to measure the position of the stage, resulting in a measurement error due to an increase in the size of the apparatus and a complicated inter-axis correction. There was a problem such as an increase.

  Therefore, in order to accurately detect the position of a measurement object having a plurality of degrees of freedom, a linear encoder in which a scale is manufactured in a two-dimensional direction has been studied. However, the linear encoder must have a constant work distance, which is the relative distance between the scale and the sensor. Therefore, even if a linear encoder with graduations in the two-dimensional direction is attached to a device that has degrees of freedom in the XY plane and the three Z-axis linear motion axes perpendicular to the XY plane, measurement is performed by changing the work distance. There is a problem that it is out of the possible area.

  On the other hand, as a position measurement sensor (position measurement device) that can measure multiple axes even when the work distance changes, the measurement reference plane with a shape whose inclination changes periodically and the change in inclination are measured. A device using an angle sensor has been devised (see Patent Document 1).

  Specifically, this position measuring apparatus converts the inclination of light reflected from the measurement reference plane into a two-dimensional position on the light receiving element using an angle sensor, using an autocollimation method. Then, the position information of the object is measured by reading the periodic change of the scale based on the change of the scale angle. Accordingly, the position in the two-dimensional direction can be independently measured without being affected by the change in the work distance.

Japanese Patent No. 2960013

  In the position measurement apparatus described in Patent Document 1, the resolution can be increased by reducing the interval between the scales. However, if the scale interval of the measurement reference surface is reduced, the laser light emitted from the light source to the measurement reference surface is diffracted, and the reflected light does not change in inclination.

  For this reason, in the position measuring apparatus that reads scales by the autocollimation method as described in Patent Document 1, there is a problem that measurement becomes difficult if the resolution is improved by reducing the scale interval.

  Accordingly, an object of the present invention is to provide a high-resolution position measuring apparatus that can measure even when the work distance changes.

  The position measuring device of the present invention includes a light source, a first reflection surface that reflects a part of the light emitted from the light source, and a second reflection surface that reflects light transmitted through the first reflection surface, Interference light is formed by the reflected light reflected by the first reflecting surface and the reflected light reflected by the second reflecting surface, and the relative distance between the first reflecting surface and the second reflecting surface is periodically changed. A periodic change of the light intensity of the interference light, which is changed by relative movement of the scale part to be performed, a light receiving sensor for detecting the light intensity of the interference light, and the light source and the scale part in parallel, to position information. And an arithmetic unit for calculating.

  The method for manufacturing a workpiece according to the present invention is a method for manufacturing a workpiece in which the workpiece and a tool are moved relative to each other to cut the workpiece, and the position measured by the position measuring device. The workpiece is machined by relatively moving the workpiece and the tool according to information.

  The molded product of the present invention is molded using a mold manufactured by the method for manufacturing a workpiece.

  According to the present invention, the scale portion has the first reflecting surface that reflects a part of the light from the light source, and the second reflecting surface that reflects the light transmitted through the first reflecting surface. The light intensity of the interference light formed by the light reflected on the reflecting surface is measured by the light receiving sensor. Since the relative distance between the first and second reflecting surfaces changes periodically, the change in the optical path difference becomes position information and is measured as a change in the light intensity of the interference light. Then, by calculating the change in the light intensity of the interference light into the position information by the calculation unit, the position of the measurement reference can be measured regardless of the change in the work distance. The measurement resolution of the position measurement device can be improved by increasing the relative distance change per unit distance between the first reflection surface and the second reflection surface that generate the interference light.

The schematic diagram which shows the multi-axis processing apparatus by which the position measuring device which concerns on the 1st Embodiment of this invention is mounted. FIG. 2 is a side sectional view of the multi-axis machining apparatus of FIG. 1. The schematic diagram which shows the position measuring apparatus which measures a one-dimensional position. The schematic diagram which shows the change of the voltage output which the position measuring device of FIG. 3 measured. The schematic diagram which shows the position measuring apparatus which measures a two-dimensional position. The schematic diagram which shows the change of the voltage output which the position measuring device of FIG. 5 measured. The schematic diagram which shows the position measuring device which concerns on 2nd Embodiment. The schematic diagram which shows the position measuring device which concerns on 3rd Embodiment. The schematic diagram which shows other embodiment of a scale part.

[First Embodiment]
[Schematic structure of multi-axis machining equipment]
Hereinafter, the position measuring device 1 according to the embodiment of the present invention will be described with reference to FIGS. First, based on FIG.1 and FIG.2, the multi-axis processing apparatus 100 in which the said position measuring apparatus 1 is mounted is demonstrated. In the following description, the directions of the XYZ axes are set with reference to the scale unit 30 of the position measuring device 1.

  The multi-axis machining apparatus 100 is a four-axis machining apparatus that is configured to be able to move the tool 111 in the three axis directions of the XYZ axes and to rotate around the Y axis. And a work holding unit 120.

  The workpiece holding unit 120 that holds the workpiece W includes a rotary shaft 124 to which the workpiece W is attached at the tip thereof, a work frame 121 that rotatably supports the rotary shaft 124, a support frame 122 that supports the work frame 121, 123. The support frames 122 and 123 are formed in a substantially U shape in plan view by a pair of leg portions 122 that support both end portions of the work frame 121 and a wall portion 123 that connects between the leg portions. The tool holding unit 110 is disposed in a recess formed by the work frame 121 and the support frames 122 and 123 so that the work W at the tip of the rotating shaft 124 and the tool 111 face each other. It is like that.

On the other hand, the tool holder 110 for holding the tool 111 is configured to control the position of the tool 111 in the 4 axial XYZ.theta. _Y. Specifically, it has the tool stage 113, 114 and 115 to drive the three axes of the XYZ, a rotating stage 112 for rotary indexing around theta _Y axis, a.

  The tool stages 113, 114, and 115 include a Y-axis stage 115 that moves up and down in the Y-axis direction, an X-axis stage 114 that is movable in the X-axis direction on the Y-axis stage, and a Z-axis direction on the X-axis stage. And a movable Z-axis stage 113. The rotary stage 112 is configured to be rotatable about the Y axis on the Z axis stage 113, and the tool 111 is attached to a tool holder 116 provided on the rotary stage 112.

  Further, the multi-axis machining apparatus 100 includes a position measurement apparatus 1 in order to detect a relative positional relationship between the workpiece W and the tool 111. The position measuring apparatus 1 includes a scale unit 30 serving as a measurement reference, a sensor unit 10 attached to a moving body, and an arithmetic unit 20 described in detail later. The scale portion 30 is attached to a wall portion 123 that is a plane perpendicular to the ground, and the sensor portion 10 is attached to a Z-axis stage 113 that is a linearly moving body closest to the tool 111. The direction position is detected. In addition to the position measuring device 1, the multi-axis machining apparatus 100 includes a Z-axis sensor (not shown) that detects the position of the tool 111 in the Z-axis direction, and a rotation angle sensor (not shown) that detects the rotation angle of the tool 111. have.

  The multi-axis machining apparatus 100 detects the relative positional relationship between the tool 111 and the workpiece W by using the position measuring device 1, the Z-axis sensor, and the rotation angle sensor. It is configured to perform spherical cutting. The tool holding unit 110 is insulated from the work holding unit 120 by a vibration isolation table or the like so that vibrations when the rotating shaft 124 rotates are not transmitted.

  The position measuring apparatus 1 of the present invention can measure the relative positional relationship between the tool 111 and the workpiece W with high accuracy. Therefore, the workpiece and the tool are relatively moved according to the position information measured by the position measuring device of the present invention, and the workpiece (work) is cut with the tool, thereby achieving high accuracy. Processing can be performed. In particular, such a manufacturing method can be suitably used for processing an optical component that requires a highly accurate shape. Moreover, it can be used suitably also for the process of the type | mold for shape | molding an optical component and the type | mold used for nanoimprint etc. for which a highly accurate shape is calculated | required similarly. A molded product such as an optical component or a circuit board molded using the mold thus processed can obtain very high accuracy. For the molding, known techniques such as injection molding and embossing can be applied.

[Structure of position measuring device]
Next, the above-described position measuring apparatus 1 will be described in detail with reference to FIGS. FIG. 3 is a schematic diagram of the position measuring device 1 when only the movement in the uniaxial direction (X-axis direction) is considered in order to briefly explain the principle of the position measuring device 1.

  As shown in FIG. 3, the position measurement device 1 includes a sensor unit 10, a scale unit 30, and a calculation unit 20. The sensor unit 10 that measures the relative movement in the parallel direction of the scale unit 30 measurement target includes a light source 11 that emits laser light of a predetermined wavelength, a polarizing beam splitter 12, a quarter wavelength plate 13, and a light receiving sensor 14. It is configured.

  The polarizing beam splitter 12 and the quarter wavelength plate 13 are arranged between the light source 11 and the scale portion 30 in the order of the polarization beam splitter 12 and the quarter wavelength plate 13 from the light source side toward the scale portion side. ing.

Therefore, the P-polarized laser light L _S emitted from the light source 11 passes through the polarizing beam splitter 12, and the polarization state is changed to circularly polarized light by the quarter-wave plate 13 and enters the scale unit 30. Then, the lights L _r1 and L _r2 reflected by the scale unit 30 pass through the quarter-wave plate 13 again, the polarization state is changed to S-polarized light, reflected by the polarization beam splitter 12, and reflected to the light receiving sensor 14. Incident. The light receiving element of the light receiving sensor 14 is a PD (Photodiode), PSD (Position Sensitive Detector), CCD (Charge Coupled Device), or the like, and measures a change in the light intensity of the laser light.

By the way, the scale part 30 reflects the first reflection surface 31 on which the first reflection film that reflects a part of the light L _S emitted from the light source 11 is formed, and the light transmitted through the first reflection surface 31. And a second reflecting surface 32 on which a second reflecting film is formed. The first and second reflecting surfaces 31 and 32 are disposed so as to be parallel to each other at a predetermined distance. The relative distance d between the first reflecting surface 31 and the second reflecting surface is an optical path difference, and is reflected by the reflected light L _r1 reflected by the first reflecting surface 31 and the second reflecting surface 32. The interference light L _i is formed by the reflected light L _r2 .

That is, the reflected light reflected from the scale unit 30 toward the light receiving sensor 14 is reflected by the reflected light L _r1 reflected by the first reflecting surface 31 and the reflected light L _r2 reflected by the second reflecting surface 32. is formed interference light L _i. Then, the light receiving sensor 14 is adapted to detect the light intensity of the interference light L _i.

  Further, the scale portion 30 is configured to periodically change the relative distance between the first reflecting surface 31 and the second reflecting surface 32. Specifically, a scale pattern is formed on the second reflecting surface 32 so as to change in height (amplitude) in a predetermined direction at a predetermined cycle by a combination of planes. In the present embodiment, when the surface is cut in one direction (for example, the X-axis direction), the second reflecting surface 32 has a triangular wave cross section (see FIG. 3).

In other words, the height (amplitude) A1 in the X-axis direction of the surface of the second reflecting surface 32 is periodically changed in the form as shown in Equation ₁ . Therefore, when the sensor unit 10 are relatively moved in the X-axis direction relative to the scale portion 30, the optical path of the interference light L _i of the laser beam L _r1, L _r2 reflected by the first reflecting surface 31 and the second reflecting surface 32 The difference changes twice as much as the amplitude A ₁ of the second reflecting surface 32 expressed by Equation ( ₁ ).

ｆ（ｘ）：位置Ｘにおける高さ、Ａ_１：形状の振幅、λ_ｘ：形状の周期（波長）

f (x): height at position X, A ₁ : shape amplitude, λ _x : shape period (wavelength)

Therefore, when the shape amplitude A ₁ is an integral multiple of ¼ of the wavelength λ _L of the laser light L _S , the interference light L _i undergoes a change that repeats light and dark continuously in the shape period λ _x . Light-receiving sensor 14 detects the brightness of the interference light L _i, resulting in a sine wave output with the same period as dark. (See FIG. 4).

A change in the period of the output voltage detected by the light receiving sensor 14 is calculated by the calculation unit 20, and is converted into position information of the measurement target by obtaining phase information and performing electrical division. That is, the position measuring apparatus 1 uses the optical path difference between the laser beams L _r1 and L _r2 as position information of the measurement target, and the measurement target (sensor unit 10, light source 11) and the scale unit 30 are relatively moved in parallel. the change in optical path difference which varies by measures as the period variation of the light intensity of the interference light L _i. And the position of a measuring object is measured by calculating the periodic change of the measured light intensity into position information.

[When measuring two-dimensional directions simultaneously]
By the way, when a moving body that moves in a plurality of axial directions is a measurement target, the position measuring apparatus 1 is usually configured so that the number of position sensors is as small as possible because the correction between axes is simple and the measurement error is reduced. The two-dimensional position can be detected.

  When detecting the two-dimensional position of the measurement target, as shown in FIG. 5, the scale unit 30 described above has a configuration capable of detecting the position of the measurement target in the biaxial direction. Specifically, the scale portion 30 has a pattern shape in which the height periodically increases and decreases in two different directions on the same plane on the second reflective surface 32, and the first and second reflective surfaces in the two different directions. The relative distance between 31 and 32 is changed.

  In the present embodiment, a shape pattern represented by Formula 2 in which regular quadrangular pyramids are aligned in the XY axis direction is formed on the surface of the second reflecting surface 32. Thereby, the surface of the scale part 30 will have a triangular wave-shaped cross section in each of the X-axis direction and the Y-axis direction, and a scale having sensitivity in these XY two-axis directions can be configured.

ｆ（ｘ，ｙ）：ある位置（ｘ，ｙ）における高さ、Ａ_１：Ｘ軸方向の振幅、λ_ｘ：Ｘ軸方向の周期、Ａ_２：Ｙ軸方向の振幅、λ_ｙ：Ｙ軸方向の周期（波長）

f (x, y): height at a certain position (x, y), A ₁ : amplitude in the X-axis direction, λ _x : period in the X-axis direction, A ₂ : amplitude in the Y-axis direction, λ _y : Y-axis Directional period (wavelength)

  Further, one light receiving sensor 14 can detect only a change in light intensity in one axial direction. Therefore, the position measuring device 1 has a plurality of light receiving sensors 14, and any one of the light receiving sensors 14 can always detect a periodic change in light intensity in each direction of the shape pattern. It arrange | positions so that it may become a position.

  Specifically, the shape pattern of the second reflecting surface 32 is formed by a combination of a surface having sensitivity only in the X-axis direction and a surface having sensitivity only in the Y-axis direction. For this reason, since any one of the light receiving sensors 14 always detects a change in the surface having sensitivity to each of the XY axes, the plurality of sensor units 10a and 10b are arranged at intervals of an integral multiple of the half wavelength λ / 2. It is installed. In addition, the angle formed by the first sensor unit 10a and the second sensor unit 10b is half the angle formed by the two directions having sensitivity, and the second sensor unit 10b is half the wavelength λ with respect to the first sensor unit 10a. More preferably, they are arranged at intervals of an integral multiple of / 2.

  Thereby, no matter how the scale unit 30 moves in the biaxial direction in which the scale unit 30 has sensitivity, the light receiving sensor 14 of any one of the sensor units 10 changes the periodic change in light intensity based on the amount of movement in each axial direction. It can be detected continuously.

That is, if it can not detect the interference light L _i of the light receiving sensor 14 is reflected on a surface that is sensitive to one axis direction of the second sensor unit 10b, the surface of the light receiving sensor 14 of the first sensor portion 10a is sensitive The interference light L _i reflected by is detected. Further, if it can not detect the interference light L _i of the light receiving sensor 14 is reflected on a surface that is sensitive to one axis direction of the first sensor portion 10a, the surface of the light receiving sensor 14 of the second sensor unit 10b is sensitive The interference light L _i reflected by is detected.

  Therefore, as shown in FIG. 6, the movement of the measurement object is measured by the output voltage V1 of the light receiving sensor 14 of the continuous first sensor unit 10a and the output voltage V2 detected by the light receiving sensor 14 of the second sensor unit 10b. can do. Since the position of the measurement target in each axial direction can be calculated based on the periodic change of the output voltages V1 and V2, the position of the measurement target in two dimensions can be measured.

  As described above, the relative movement amount between the measurement target and the scale unit 30 and the output voltage of the light receiving element have the relationship shown in FIGS. 4 and 6 regardless of changes in the work distance (Z-axis direction position). For this reason, the position measuring apparatus 1 can accurately measure the measurement target position regardless of the work distance.

  Moreover, since the resolution of the position measuring device 1 can be improved by increasing the amplitudes A1 and A2 of the scale shape of the second reflecting surface 32, high resolution can be achieved.

  Further, since the scale shape pattern is configured by a combination of planes, the laser light can be caused to interfere with the plane wave. This can prevent a decrease in the S / N ratio with respect to the electrical noise of the light receiving sensor 14 at a specific measurement location. Thereby, the number of electrical divisions of the voltage output obtained from the sensor can be increased and high resolution can be obtained.

  In addition, since the position measuring device 1 that measures a two-dimensional position measures at a position closer to the machining point as compared with a device that measures the position using one or more position sensors for each drive shaft, Abbe error and attitude It is possible to reduce the influence of change and temperature drift and enable high-precision measurement.

Incidentally, as a condition for the interference light L _i is generated, in this embodiment, is sufficiently low aspect ratio of the triangular shape of the second reflection surface 32. Further, the relationship between the distance d between the first reflecting surface 31 and the second reflecting surface 32 and the diameter 2r of the incident laser beam is set so as to satisfy Equation 3. When the relationship of Equation 2 is satisfied, the two reflected lights L _r1 and L _r2 overlap to generate interference light L _i and return to the sensor unit 10.

φ：三角波形状のアスペクト比で定まる傾き角

φ: Angle of inclination determined by the aspect ratio of the triangular wave shape

Moreover, since they produce interference light L _i if Kasanariae two reflected lights L _r1, L _r2 even slightly, can be measured by adjusting the size and sensitivity of the light receiving element, the interference intensity varies in this embodiment In order to prevent dullness, 90% or more of the reflected light L _r1 and L _r2 overlap each other.

Specifically, when considering the X-axis direction, when A ₁ = 1.58 μm and λ _x = 1000 μm and the aspect ratio is 0.95 / 250, if d = 1250 μm and r = 100 μm, the first reflecting surface Thus, it is possible to obtain a configuration in which the reflected light of 31 and the second reflecting surface 32 overlap 90% or more. If the wavelength of the light source is 632.8 nm and the number of electrical divisions is 5000, the measurement resolution can be 8.3 nm.

Further, when the light intensities of the reflected light from the first reflecting surface 31 and the second reflecting surface 32 match, the contrast of interference is maximized. Therefore, it is desirable that the reflectance of the first reflecting film is normally about 50%. . The reflectance of the second reflective film is preferably 100%. Furthermore, in order to improve the overlap of the reflected lights L _r1 and L _r2 , it is desirable to reduce the distance d between the first reflecting surface 31 and the second reflecting surface 32 as much as possible.

[Second Embodiment]
Next, the position measuring device 1 according to the second embodiment will be described. In the second embodiment, only the configuration of the sensor unit 10 is different from that of the first embodiment, and description of other common configurations is omitted.

  As shown in FIG. 7, the sensor unit 10 includes a diffraction grating 15 and a collimating lens (optical lens) 16 between the light source 11 and the scale unit 30, more specifically between the light source 11 and the polarization beam splitter 12. Is arranged.

The diffraction grating 15 and the collimating lens 16 are arranged in this order from the light source side to the scale part side, and the laser light L _S emitted from the light source 11 is incident on the diffraction grating 15 to be diffracted light. L _S1 . Then, after becoming diffracted light L _S1 , it enters the collimating lens 16 and becomes a plurality of parallel lights L _S2 . When using a plurality of lights, it is necessary to measure the same phase in the shape of the second reflecting surface 32. Relationship spacing of the parallel light L _S2 is to be the integral multiple of the shape distance between the second reflecting surface 32, the shape distance λx focal length f and the second reflecting surface 32 of the collimating lens 16, [lambda] y is shown in Equation 4 It becomes. In Equation 4, θ is the diffraction order of ± first-order light generated in the diffraction grating 15 and has the relationship shown in Equation 5 with respect to the wavelength λ _L of the laser light L _S1 and the grating interval P of the diffraction grating 15.

The spot radius r of the laser light _LS2 after passing through the collimating lens 16 is expressed by Equation 6. In Equation 6, m is the number of gratings included in the laser light incident on the diffraction grating 15.

When the laser light L _S emitted from the light source 11 is a spot diameter of a few mm, since m may take a value of about 100 to 1000, r is the very fine spot size and number to several 10μm .

When the spot diameter is reduced, the distribution of the optical path difference in the spot of the laser light L _S is suppressed, and the dullness of the light intensity change on the light receiving element is reduced. Therefore, the position measurement resolution can be improved by making the second reflecting surface 32 a shape having a higher aspect ratio than that of the first embodiment.

When the structure of the second reflecting surface 32 is made finer than the first embodiment with an aspect ratio of 79/1250 of A ₁ = 316 nm and λ _x = 10 μm, r = 5 μm and d = 3.5 μm The reflected light L _r1 and L _r2 are configured to overlap 90% or more. If the wavelength of the light source is 632.8 nm and the number of electrical divisions is 5000, the measurement resolution can be 0.5 nm. Moreover, since the variation in the shape of the 2nd reflective surface 32 is averaged by injecting several parallel light into the 2nd reflective surface 32, a position measurement precision can be improved.

[Third Embodiment]
Next, the position measuring apparatus 1 according to the third embodiment will be described. In the third embodiment, a diffraction grating is used in place of the collimating lens 16 of the second embodiment. Therefore, only the configuration different from the second embodiment will be described, and the description of the same configuration will be omitted.

  As shown in FIG. 8, the sensor unit 10 includes a first diffraction grating 15 and a second diffraction grating 17 between the light source 11 and the scale unit 30, more specifically between the light source 11 and the polarization beam splitter 12. Has been placed.

The first and second diffraction gratings 15 and 17 are arranged in this order from the light source side to the scale portion side, and the second diffraction grating 17 is similar to the collimating lens 16 in the first diffraction pattern. The diffracted light L _S1 that has passed through the grating 15 is converted into parallel light L _S2 .

In this configuration, it is necessary to suppress the spread of the laser beam by widening the grating interval of the diffraction gratings 15 and 17 to about several tens to 100 μm, but the influence of the alignment error is reduced as compared with the case where the collimating lens 16 is used. Therefore, the interval of the parallel light L _S2 after passing through the first diffraction grating 15 can be made to coincide with the shape interval of the second reflecting surface 32 with high accuracy, and positioning of the optical element is performed when the light is converted into a minute spot. The error can be reduced.

  In the first to third embodiments described above, the scale shape pattern is created on the second reflection surface 32, but the shape pattern may be formed on the first reflection surface 31. A scale shape pattern may be formed on both the first and second reflecting surfaces 31 and 32.

  Furthermore, in the first to third embodiments described above, the first reflecting surface 31 and the second reflecting surface 32 are formed on the front and back surfaces of a parallel plate, but may be separated into two elements.

  The shape pattern of the scale may be a sawtooth wave, a rectangular wave, or a sine wave shape as shown in FIG. 9, but when the sensor unit 10 is used alone, the shape is continuous and the shape is continuous. A triangular wave shape is desirable. Further, as described above, when a scale shape pattern is formed with a curve such as a sine wave shape, the detection accuracy decreases at a specific location (for example, 90 ° or 270 °). It is desirable that a periodic pattern be formed.

  Furthermore, since it is ideal that the amplitude of the periodic shape is a continuous sine wave when performing signal processing, it is desirable that the amplitude is an integral multiple of ¼ of the wavelength of light.

  Moreover, in order to suppress the influence of the measurement error when the work distance changes extremely, the scale portion 30 as the measurement reference surface is installed on the XY plane in the multi-axis machining apparatus 100, but the driving range is the most depending on the machining mode. It is desirable to install it on a plane perpendicular to the short axis. It is desirable that the workpiece W and the scale unit 30 be arranged as close as possible to the temperature adjustment so as not to cause a relative position change due to a temperature change or the like.

  Further, the arithmetic unit 20 may be incorporated in a dedicated computer for controlling the device on which the position measuring device 1 is mounted, a general-purpose computer, or may be incorporated in the sensor unit (measuring unit) 10. Further, instead of the collimating lens 16, any known optical lens that polarizes diffracted light into parallel light may be used.

Furthermore, the sensor unit 10 may be configured to divide the light L _S emitted from the light source 11 and may be configured to provide a plurality of light receiving sensors (optical sensors) 14 for one light source 11. Needless to say, the inventions described in the first to third embodiments may be combined in any way.

1: position measuring device, 11: light source, 14: light receiving sensor, 15: first diffraction grating, 16: collimating lens (optical lens), 17: second diffraction grating, 20: calculation unit, 30: scale unit, 31: First reflection surface, 32: second reflection surface

Claims (9)

A light source;
Reflected light that has a first reflecting surface that reflects part of the light emitted from the light source and a second reflecting surface that reflects light that has passed through the first reflecting surface, and is reflected by the first reflecting surface. And a reflected light reflected by the second reflecting surface to form interference light, and a scale portion that periodically changes the relative distance between the first reflecting surface and the second reflecting surface;
A light receiving sensor for detecting the light intensity of the interference light;
A calculation unit that calculates a periodic change in the light intensity of the interference light, which is changed by relative movement of the light source and the scale unit in parallel, into position information;
A position measuring device characterized by that. Having a plurality of the light receiving sensors,
At least one of the first reflective surface or the second reflective surface is formed with a shape pattern whose height periodically increases or decreases in two different directions on the same plane,
A plurality of the light receiving sensors are arranged such that any one of the light receiving sensors has a positional relationship in which a periodic change in light intensity based on an increase or decrease in height in each direction of the shape pattern can always be detected.
The position measuring device according to claim 1. At least one of the first reflecting surface or the second reflecting surface has a triangular wave-shaped cross section when cut in one direction.
The position measuring device according to claim 1. A diffraction grating disposed between the light source and the scale portion;
An optical lens that is disposed between the diffraction grating and the scale portion and converts the diffracted light that has passed through the diffraction grating into parallel light,
The position measuring device according to claim 1. A first diffraction grating disposed between the light source and the scale portion;
A second diffraction grating that is disposed between the first diffraction grating and the scale portion and converts the diffracted light that has passed through the first diffraction grating into parallel light,
The position measuring device according to claim 1. A method of manufacturing a workpiece by cutting the workpiece by relatively moving the workpiece and a tool,
Machining the workpiece by relatively moving the workpiece and the tool according to the position information measured by the position measuring device according to any one of claims 1 to 5.
A method for manufacturing a workpiece. The workpiece is a mold for molding an optical component.
A method for manufacturing a workpiece according to claim 6. The workpiece is a mold used for nanoimprinting,
A method for manufacturing a workpiece according to claim 6. Molded using a mold manufactured by the method for manufacturing a workpiece according to any one of claims 6 to 8.
A molded product characterized by that.

Images