Displacement meter, manufacturing system, and article manufacturing method

Abstract

To provide a displacement meter that can easily change the direction of displacement to be measured of an object.SOLUTION: A displacement meter according to the present invention comprises: an illumination unit that makes illumination light incident on an object to illuminate the object; an imaging unit that includes an optical element that guides first light from the object so as to rotate the image of the object, and receives the first light passing through the optical element to pick up the image of the object; and an operation unit that, from a first image picked up by the imaging unit at a first time and a second image picked up at a second time, calculates the amount of displacement of the object between the first time and the second time. The optical element guides, to the object, at least part of the illumination light incident from the illumination unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a displacement meter for measuring the displacement amount of an object.

Background Art

[0002] Conventionally, there is known a displacement meter that measures the displacement amount of an object in a non-contact manner by receiving light from the object generated by irradiating the object with laser light before and after the displacement of the object. Patent Document 1 discloses a displacement meter that measures the displacement amount of an object in a predetermined direction using a one-dimensional image sensor formed from a plurality of pixels arranged in the predetermined direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the displacement meter disclosed in Patent Document 1, when displacement of an object occurs in a predetermined direction that forms an angle θ with the arrangement direction of a plurality of pixels in the one-dimensional image sensor, the measured displacement amount is cosθ times the displacement amount of the object in the predetermined direction. That is, when the displacement direction of the object and the arrangement direction of a plurality of pixels in the one-dimensional image sensor are orthogonal to each other, it becomes impossible to measure the displacement amount of the object with the one-dimensional image sensor.

[0005] Therefore, in order to accurately measure the displacement amount of an object in the displacement meter disclosed in Patent Document 1, it is necessary to align the arrangement direction of a plurality of pixels in the one-dimensional image sensor housed in the housing with the displacement direction of the object by changing the posture of the housing. Therefore, the measurement process becomes complicated. Accordingly, an object of the present invention is to provide a displacement meter capable of easily changing the direction of the measured displacement of an object. [Means for Solving the Problems]

[0006] The displacement meter according to the present invention includes an illumination unit that illuminates an object by causing illumination light to enter the object, and an optical element that guides first light from the object so as to rotate an image of the object. The displacement meter further includes an imaging unit that captures an image of the object by receiving the first light that has passed through the optical element, and an arithmetic unit that calculates the amount of displacement of the object between a first time and a second time from a first image captured at the first time and a second image captured at the second time by the imaging unit. The optical element is characterized by guiding at least a part of the illumination light incident from the illumination unit to the object. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a displacement meter capable of easily changing the direction of the measured displacement of an object. [Brief Description of the Drawings]

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0009] The displacement meter according to the present embodiment will be described in detail below with reference to the attached drawings. Note that the drawings shown below may be drawn at a scale different from the actual one in order to facilitate understanding of the present embodiment. Also, hereinafter, in the line sensor 6, the direction in which a plurality of photoelectric conversion elements are arranged is defined as the Y direction (second direction), the direction perpendicular to the Y direction and parallel to the optical axis of the light receiving optical system is defined as the Z direction (first direction), and the direction perpendicular to the Y direction and the Z direction is defined as the X direction.

[0010] [First Embodiment] Conventionally, a displacement meter is known that irradiates a laser beam onto an object before and after the displacement of the object to obtain a speckle distribution, and calculates the displacement amount of the object by calculating the extreme value of the cross-correlation function between the signals obtained by photoelectrically converting the respective speckle distributions. Also, in such a displacement meter, it is known that a one-dimensional image sensor formed of a plurality of pixels arranged in a predetermined direction is used to accurately measure the displacement amount of the object in the predetermined direction.

[0011] However, in such a conventional displacement meter, if the arrangement direction of the plurality of pixels in the one-dimensional image sensor and the direction of the displacement of the object are different from each other, a measurement error will occur. For example, when the object is displaced in a predetermined direction that forms an angle θ with respect to the arrangement direction, the displacement amount measured by the one-dimensional image sensor is cosθ times the actual displacement amount of the object in the predetermined direction.

[0012] That is, when the direction of displacement of the object and the arrangement direction of the plurality of pixels in the one-dimensional image sensor are orthogonal to each other, the displacement amount of the object cannot be measured by the one-dimensional image sensor. Therefore, in order to accurately measure the displacement amount of an object with such a conventional displacement meter, it is necessary to align the arrangement direction of a plurality of pixels in the one-dimensional image sensor housed in the housing with the direction of the displacement of the object by changing the posture of the housing. As a result, the measurement process becomes complicated.

[0013] In addition, in the conventional displacement meter as described above, there is also known one that accurately measures the displacement amount in a predetermined plane of an object using a two-dimensional image sensor. That is, in such a conventional displacement meter, even if the direction of displacement of an object changes within a predetermined plane, the displacement amount of the object can be accurately measured. However, the cost for providing the two-dimensional image sensor including the peripheral circuit increases.

[0014] In addition, in a two-dimensional image sensor, the amount of image data acquired is larger than that of a one-dimensional image sensor. Therefore, the time required for each of acquiring the data of the image, transferring the data, and calculating the displacement amount of the object by processing the data increases. That is, in the conventional displacement meter using such a two-dimensional image sensor, high cost and a decrease in throughput occur.

[0015] Therefore, an object of the present embodiment is to provide a non-contact displacement meter that can measure the displacement amount of an object while suppressing a decrease in throughput and an increase in cost by simply changing the direction of the displacement of the object to be measured. FIG. 1 shows a partially schematic YZ cross-sectional internal projection view of a displacement meter 50 (length measuring instrument) according to the first embodiment.

[0016] The displacement meter 50 according to the present embodiment can non-contact measure the displacement amount of an object 2 arranged to face each other. The displacement meter 50 according to the present embodiment includes a light source 3, a first condenser optical element 4, a second condenser optical element 5, a line sensor 6 (imaging element), a diaphragm 7, an image rotator 8 (optical element), an image rotator holding portion 9 (FIG. 3), a signal processing unit 11, and a control unit 12. Also, in the displacement meter 50 according to the present embodiment, each of the above-described components is housed in the housing 40.

[0017] In the displacement meter 50 according to the present embodiment, an illumination optical system is formed by the first condenser optical element 4 and the image rotator 8, and a light receiving optical system is formed by the image rotator 8, the second condenser optical element 5, and the aperture 7. Also, in the displacement meter 50 according to the present embodiment, an illumination unit that illuminates a predetermined region (illumination region) on a predetermined surface of the object 2 by causing illumination light to enter the object 2 is formed by the light source 3, the first condenser optical element 4, and the image rotator 8. Also, in the displacement meter 50 according to the present embodiment, an imaging unit that captures an image of the object 2 by receiving light (first light), for example, diffusely reflected light, from the object 2 is formed by the image rotator 8, the second condenser optical element 5, the aperture 7, and the line sensor 6.

[0018] The light source 3 is an incoherent light source such as an LED or a halogen lamp that emits, for example, white light, and can be appropriately selected from a plurality of such incoherent light sources. The first condenser optical element 4 is formed by at least one lens (refractive optical element) appropriately selected according to the size and shape of the illumination region on the object 2. The second condenser optical element 5 is formed by at least one lens (refractive optical element) appropriately selected according to the resolution set in the light receiving optical system.

[0019] The aperture 7 is disposed at a position separated from the second condenser optical element 5 by the focal length of the second condenser optical element 5 between the second condenser optical element 5 and the line sensor 6. In the displacement meter 50 according to the present embodiment, by providing the aperture 7 in this way, a telecentric light receiving optical system can be formed on the object 2 side.

[0020] That is, in the displacement meter 50 according to the present embodiment, by forming such an object-side telecentric optical system, a robust measurement system capable of measuring the displacement amount of the object 2 at a constant magnification even when the distance to the object 2 changes can be formed. Further, by forming an object-side telecentric optical system, it is possible to set the optical magnification according to the position of the line sensor 6 with respect to the aperture 7.

[0021] Also, by appropriately arranging a condensing optical element between the aperture 7 and the line sensor 6, it is possible to form a both-side telecentric optical system. When a both-side telecentric optical system is formed in the displacement meter 50 according to the present embodiment, the magnification of the light-receiving optical system is determined according to the ratio between the second condensing optical element 5 and the focal lengths of the respective condensing optical elements. And the determined magnification is constant regardless of the position of the line sensor 6.

[0022] The line sensor 6 is a photoelectric conversion element array extending in the Y direction by arranging a plurality of photoelectric conversion elements (pixels) in the one-dimensional direction, specifically, the Y direction. In the displacement meter 50 according to the present embodiment, by using the line sensor 6, the amount of data transferred and used for calculation is reduced compared to the case of using an area sensor, so that high-speed measurement is possible and the throughput can be improved.

[0023] And in the displacement meter 50 according to the present embodiment, an image signal is generated by photoelectrically converting the light beam received by the line sensor 6, and the generated image signal is input to the signal processing unit 11 (calculation unit). The signal processing unit 11 is formed of an FPGA (Field Programmable Gate Array), a microcomputer, or the like, and calculates the displacement amount of the object 2 by processing the image signal output from the line sensor 6.

[0024] For example, the signal processing unit 11 calculates the cross-correlation function between an image signal (first signal) acquired at a predetermined timing (first time) and an image signal (second signal) acquired at another predetermined timing (second time). More specifically, for example, the signal processing unit 11 acquires a first image signal generated by photoelectrically converting the luminance distribution in an image (first image) captured at a predetermined timing. Next, a second image signal generated by photoelectrically converting the luminance distribution in an image (second image) captured at another predetermined timing is acquired, and the cross-correlation function between the acquired first image signal and the second image signal is calculated.

[0025] Then, the displacement amount of the object 2 between the above-mentioned predetermined timing and the above-mentioned another predetermined timing can be calculated from the position of the peak (extreme value) in the calculated cross-correlation function. Note that the signal processing unit 11 can calculate the displacement amount of the object 2 with a resolution of one pixel or less from the information on the position of the peak in the calculated cross-correlation function and the information on the positions before and after the position of the peak.

[0026] In the displacement meter 50 according to the present embodiment, after the light beam emitted from the light source 3 is condensed by the first condensing optical element 4, it is guided to the object 2 to illuminate the object 2. In addition, at least a part of the light beam condensed by the first condensing optical element 4 passes through the image rotator 8 and then is guided to the object 2.

[0027] The diffusely reflected light diffusely reflected by the object 2 passes through the image rotator 8, is condensed by the second condensing optical element 5, passes through the aperture 7, and then is guided to the line sensor 6. Thereby, an image reflecting the pattern on a predetermined surface of the object 2 illuminated by the line sensor 6 is formed.

[0028] In the displacement meter 50 according to the present embodiment, an image rotator 8 that guides light from the object 2 so as to rotate the image of the object 2 around the Z direction is provided between the object 2 and the second condensing optical element 5. In the displacement meter 50 according to the present embodiment, by providing the image rotator 8 in this way, the direction of the displacement measured for the object 2 can be adjusted (changed, determined, selected).

[0029] Specifically, as shown in FIG. 1, in the line sensor 6, a plurality of light source conversion elements are arranged in the Y direction. At this time, in a conventional displacement meter having the same configuration as the displacement meter 50 according to the present embodiment except that the image rotator 8 is not provided, the displacement amount of the object 2 in the Y direction can be measured. On the other hand, in the displacement meter 50 according to the present embodiment, by rotating the provided image rotator 8 by a predetermined angle around the Z direction, the displacement amount in a predetermined direction other than the Y direction corresponding to the predetermined angle of the object 2 can be measured.

[0030] FIG. 2(a) shows a perspective view of the image rotator 8 provided in the displacement meter 50 according to the present embodiment. As shown in FIG. 2(a), the image rotator 8 provided in the displacement meter 50 according to the present embodiment is formed by a double prism.

[0031] Specifically, the image rotator 8 formed by a double prism has an object-side slope 8a facing the object 2, a sensor-side slope 8b facing the line sensor 6, a bottom surface 8c, a top surface 8d, an illumination-side side surface 8e, and an anti-illumination-side side surface 8f. As shown in FIG. 2(a), the light that has entered the image rotator 8 while refracting from the object-side slope 8a is reflected by the bottom surface 8c and then exits while refracting from the sensor-side slope 8b to the outside of the image rotator 8.

[0032] At this time, as shown in FIG. 2(a), light from a portion extending in a predetermined direction in the XY plane of the object 2 passes through the image rotator 8, so that the image of the portion is formed by rotating around the Z direction in which the bottom surface 8c of the image rotator 8 extends. Specifically, the image of the portion of the object 2 is formed by rotating around the Z axis (the rotation axis of the image of the object 2 by the image rotator 8) by twice the angle formed by the bottom surface 8c and the predetermined direction in which the portion extends in the XY plane.

[0033] That is, in the displacement meter 50 according to the present embodiment, by rotating the image rotator 8 around the Z axis by a predetermined angle, an image of the object 2 rotated by twice the predetermined angle is formed. In other words, by rotating the image rotator 8 arranged so that the bottom surface 8c is parallel to the YZ plane around the Z axis by a predetermined angle, the displacement amount of the object 2 in the direction forming twice the predetermined angle with respect to the Y direction in which the line sensor 6 extends can be measured.

[0034] For example, as shown in FIG. 1, when the image rotator 8 arranged so that the bottom surface 8c is parallel to the YZ plane is rotated by 45 degrees around the Z axis, the line sensor 6 can measure the displacement amount of the object 2 in the X direction. That is, in the displacement meter 50 according to the present embodiment, by providing the image rotator 8, the displacement amount of the object 2 in a predetermined direction in the XY plane (the first plane) perpendicular to the Z direction can be measured.

[0035] Further, when attempting to reduce the size of the displacement meter 50 according to the present embodiment in the Z direction, the illumination light from the light source 3 interferes with the image rotator 8. For example, taking the operating distance from the end face 40e of the housing 40, specifically, the position 70 mm away from the end face 40e in the Z direction on the optical axis of the light receiving optical system as the measurement center, and setting the measurable range from the measurement center in the Y direction to ±15 mm.

[0036] In addition, when the size of the field of view of the displacement meter 50 according to the present embodiment is 10 mm and the incident angle of the illumination light on the object 2 is 20 degrees, in order to sufficiently illuminate the measurable range of the object 2, the width of the illumination light needs to be 20 mm or more. When the width of the illumination light is set to 20 mm, the illumination light and the field of view interfere with each other at a position separated from the object 2 by about 30 mm.

[0037] Therefore, in the displacement meter 50 according to the present embodiment, as shown in FIG. 1, at least a part of the illumination light from the first condenser optical element 4 is guided to the object 2 after passing through the image rotator 8. When a double prism is used as the image rotator 8 provided in the displacement meter 50 according to the present embodiment, by performing optical polishing on each surface of the double prism, the illumination light can be guided to the object 2 regardless of the direction from which the illumination light enters the image rotator 8.

[0038] At least a part of the illumination light from the first condenser optical element 4 is guided to the object 2 by entering the inside of the image rotator 8 from, for example, the illumination side side surface 8e and then exiting from the object side inclined surface 8a or the anti-illumination side side surface 8f. That is, in the displacement meter 50 according to the present embodiment, the image rotator 8 also serves as a light guide for guiding the illumination light from the light source 3 to the object 2.

[0039] In the displacement meter 50 according to the present embodiment, as shown in FIG. 1, the illumination area of the object 2 by the illumination light is sufficiently larger than the measurement area of the object 2 measured by the line sensor 6. In addition, in the above configuration, there is a possibility that a part of the illumination light incident on the image rotator 8 travels toward the line sensor 6 as stray light, but such stray light can be blocked by the aperture 7.

[0040] FIG. 3 shows a projection view in the YZ cross section of the image rotator 8 and the image rotator holding portion 9 provided in the displacement meter 50 according to the present embodiment. In the displacement meter 50 according to the present embodiment, since the image rotator holding portion 9 is provided to hold the image rotator 8, the range in which the illumination light interferes with the visual field becomes even wider.

[0041] Therefore, in the displacement meter 50 according to the present embodiment, as shown in FIG. 3, an opening 9a (first opening) is formed in a portion of the image rotator holding portion 9 that faces the illumination side surface 8e of the image rotator 8. And at least a part of the illumination light from the light source 3 passes through the opening 9a formed in the image rotator holding portion 9 and then enters the inside of the image rotator 8 from the illumination side surface 8e.

[0042] That is, in the displacement meter 50 according to the present embodiment, at least a part of the illumination light from the light source 3 enters the image rotator 8 by passing through the opening 9a formed in the image rotator holding portion 9. The illumination light emitted from the image rotator 8 enters the object 2 by passing through an opening 9b (second opening) formed in the image rotator holding portion 9 so as to face the object side slope 8a of the image rotator 8.

[0043] Next, the light from the object 2 enters the image rotator 8 by passing through the opening 9b. The light that has passed through the inside of the image rotator 8 is emitted from the sensor side slope 8b of the image rotator 8 and passes through an opening 9c (third opening) formed in the image rotator holding portion 9 so as to face the sensor side slope 8b. Thereby, the light from the object 2 is guided to the line sensor 6.

[0044] As described above, in the displacement meter 50 according to the present embodiment, the illumination light is obliquely incident on the object 2 such that the optical axis of the illumination optical system and the optical axis of the light receiving optical system are non-parallel to each other in the YZ plane (second plane), but it is not limited to this. That is, in the displacement meter 50 according to the present embodiment, when projected onto the YZ plane, illumination light may be incident on the object 2 such that the optical axis of the illumination optical system and the optical axis of the light receiving optical system are substantially parallel to each other. In this case, the openings 9b and 9c may be formed in the image rotator holding portion 9, and there is no need to form the opening 9a.

[0045] In the image rotator holding portion 9, for example, the image rotator 8 can be held by adhering the anti-illumination side surface 8f to a portion facing the anti-illumination side surface 8f of the image rotator 8. And in the image rotator holding portion 9, if only the portion where the anti-illumination side surface 8f of the image rotator 8 is adhered is provided, that is, when the portion facing the illumination side surface 8e of the image rotator 8 is opened, there is no need to form the opening 9a.

[0046] As described above, in the displacement meter 50 according to the present embodiment, an image rotator 8 is provided that guides light from the object 2 so as to rotate the image of the object 2 around the Z direction. Thereby, the user can change the direction of the displacement measured for the object 2 without changing the installation direction of the housing 40 of the displacement meter 50 according to the present embodiment.

[0047] Also, in the displacement meter 50 according to the present embodiment, the image rotator 8 is provided so as to guide at least a part of the illumination light incident from the illumination unit to the object 2. Thereby, the size of the displacement meter 50 according to the present embodiment in the Z direction can be reduced.

[0048] Note that in the displacement meter 50 according to the present embodiment, a double prism is used as the image rotator 8, but it is not limited thereto. That is, as the image rotator 8, for example, a combination 8' of three reflecting surfaces as shown in FIG. 2(b) may be used, or a single optical element having the three reflecting surfaces may be used.

[0049] [Second Embodiment] FIG. 4(a) shows a schematic perspective view of an image rotator holding portion 19 provided in the displacement meter 60 according to the second embodiment. FIG. 4(b) is a diagram showing how the direction of the displacement measured for the object 2 changes in the displacement meter 60 according to the second embodiment. Note that the displacement meter 60 according to the present embodiment has the same configuration as the displacement meter 50 according to the first embodiment, except that an image rotator holding portion 19 is provided instead of the image rotator holding portion 9. Therefore, the same reference numerals are given to the same members, and the description thereof is omitted.

[0050] The image rotator holding portion 19 provided in the displacement meter 60 according to the present embodiment is configured to be rotatable about the Z-axis parallel to the extending direction of the double prism serving as the image rotator 8 while holding the double prism. Then, as shown in FIG. 4(b), by rotating the image rotator holding portion 19 about the Z-axis to change the angle of the image rotator 8 about the Z-axis, the direction of the displacement measured for the object 2 can be changed.

[0051] Specifically, by rotating the image rotator 8 by a predetermined angle about the Z-axis from the state where θ = 0 degrees, the displacement amount of the object 2 in the direction forming an angle twice the predetermined angle with respect to the Y-direction in which the line sensor 6 extends can be measured. As shown in FIG. 4(b), the state where the image rotator 8 is at θ = 0 degrees means a state where the bottom surface 8c of the image rotator 8 is parallel to the YZ plane, that is, a state where the angle (90 - θ) formed by the normal line of the bottom surface 8c with respect to the Y-axis is 90 degrees. In this case, the displacement amount of the object 2 in the Y-direction can be measured.

[0052] Then, when the image rotator 8 is rotated up to θ = 22.5 degrees, the displacement amount of the object 2 in the direction forming an angle of 45 degrees with respect to the Y-direction in the XY plane can be measured. When the image rotator 8 is rotated to θ = 45 degrees, the displacement amount of the object 2 in the X direction, which forms a 90-degree angle with respect to the Y direction in the XY plane, can be measured. When the image rotator 8 is rotated to θ = 90 degrees, the displacement amount of the object 2 in the Y direction, which forms a 180-degree angle with respect to the Y direction in the XY plane, can be measured.

[0053] As described above, in the displacement meter 60 according to the present embodiment, the direction of the displacement of the object 2 to be measured can be adjusted by rotating the image rotator 8 by rotating the image rotator holding portion 19 without changing the mounting direction of the housing 40 with respect to the object 2. Specifically, when the direction of displacement in the image of the object 2 rotated by the image rotator 8 forms an angle θ with respect to the Y direction in which the line sensor 6 extends, and the displacement amount in the direction of the displacement is L, the displacement amount of the measured object 2 is Lcosθ.

[0054] Therefore, in the displacement meter 60 according to the present embodiment, the direction of the displacement of the object 2 can be determined by rotating the image rotator 8 so that the displacement amount of the measured object 2 becomes maximum. In other words, in the displacement meter 60 according to the present embodiment, the object 2 is driven at a constant speed, and the direction of the displacement of the object 2 can be determined by rotating the image rotator 8 so that the output speed becomes the maximum value.

[0055] That is, in the displacement meter 60 according to the present embodiment, the control unit 12 causes the imaging unit to image the object 2 at different times in a state where the image rotator 8 is arranged at a plurality of angles θ around the Z axis. Next, the signal processing unit 11 calculates the displacement amount of the object 2 per unit time from the images of the object 2 captured at the different times. Then, the direction of the displacement of the object 2 can be determined from the angle θ at which the calculated displacement amount per unit time becomes the largest.

[0056] Further, in the displacement meter 60 according to the present embodiment, a cross-correlation function between image signals acquired at different timings is calculated, and the displacement amount of the object 2 is calculated from the position of the peak in the calculated cross-correlation function. In this case, it is possible to acquire both the displacement amount on the plus side and the displacement amount on the minus side in a predetermined direction. In other words, in the displacement meter 60 according to the present embodiment, in the state where the image rotator 8 shown in FIG. 4(b) is θ = 0 degrees, it is possible to acquire both the displacement amount on the plus side and the displacement amount on the minus side in the Y direction of the object 2.

[0057] That is, in the displacement meter 60 according to the present embodiment, in each of the states where the image rotator 8 is θ = 0 degrees and θ = 90 degrees, it is possible to acquire both the displacement amount on the plus side and the displacement amount on the minus side in the Y direction of the object 2. Therefore, in the displacement meter 60 according to the present embodiment, by rotating the image rotator 8 to an angle θ between 0 degrees and 90 degrees, it is possible to acquire the displacement amount of the object 2 in a predetermined azimuth in a predetermined direction within the XY plane. Therefore, in the cylindrical surface of the image rotator holding portion 19 provided in the displacement meter 60 according to the present embodiment, the opening 9a for making at least a part of the illumination light incident on the image rotator 8 does not need to be formed over the entire circumferential direction.

[0058] As described above, in the displacement meter 60 according to the present embodiment, an image rotator 8 that guides light from the object 2 so as to rotate the image of the object 2 around the Z direction is provided. Thereby, it is possible to change the direction of the displacement to be measured of the object 2 without the user changing the installation direction of the housing 40 of the displacement meter 60 according to the present embodiment. Further, in the displacement meter 60 according to the present embodiment, by providing an image rotator holding portion 19 that rotatably holds the image rotator 8, the direction of the displacement of the object 2 can be determined.

[0059] [Third Embodiment] FIG. 5 shows a schematic perspective view of the displacement meter 70 according to the third embodiment. The displacement meter 70 according to the present embodiment has the same configuration as the displacement meter 50 according to the first embodiment, except that an image rotator holding portion 29 is provided instead of the image rotator holding portion 9. Therefore, the same members are denoted by the same reference numerals and the description thereof is omitted.

[0060] In the displacement meter 70 according to the present embodiment, the image rotator holding portion 29 that holds the image rotator 8 is provided so as to be detachable from the housing 40 in which other optical elements are housed. In other words, in the displacement meter 70 according to the present embodiment, the image rotator 8 is provided so as to be insertable and removable in the optical path of the illumination light from the light source 3 and in the optical path of the light from the object 2.

[0061] For example, the image rotator holding portion 29 can be fixed to the housing 40 by a screw fastening portion (not shown). Note that the image rotator holding portion 29 may be fixed to the housing 40 via a magnet, a leaf spring, or the like.

[0062] In the displacement meter 70 according to the present embodiment, when measuring the displacement amount of the object 2 in an unknown direction, the image rotator holding portion 29 that holds the image rotator 8 is attached to the housing 40 in order to determine the unknown direction. On the other hand, when measuring the displacement amount of the object 2 in a known direction, it is not necessary to rotate the image of the object 2 by the image rotator 8 by adjusting the orientation of the housing 40 in accordance with the known direction. Therefore, the image rotator holding portion 29 is removed from the housing 40.

[0063] When the image rotator holding portion 29 is attached to the housing 40 in the displacement meter 70 according to the present embodiment, the operating distance with respect to the object 2 becomes short, so there is a risk of interfering with the object 2 due to the influence of vibration or the like. Therefore, in the displacement meter 70 according to the present embodiment, by providing the image rotator holding portion 29 that can be attached to and detached from the housing 40, an optimal configuration can be selected according to the usage situation and environment.

[0064] As described above, in the displacement meter 70 according to the present embodiment, an image rotator 8 is provided for guiding light from the object 2 so as to rotate the image of the object 2 around the Z direction. Thereby, the direction of the displacement to be measured of the object 2 can be changed without the user changing the installation direction of the housing 40 of the displacement meter 70 according to the present embodiment. Also, in the displacement meter 70 according to the present embodiment, by providing the image rotator holding portion 29 that can be attached to and detached from the housing 40, it is possible to select whether to use the image rotator 8 according to the usage situation and environment.

[0065] [Fourth Embodiment] FIGS. 6(a) and (b) respectively show partial schematic YZ cross-sectional internal projection views of the displacement meter 50 according to the first embodiment and the displacement meter 80 according to the fourth embodiment. Note that the displacement meter 80 according to the present embodiment has the same configuration as the displacement meter 50 according to the first embodiment except that a condensing optical element 10 is further provided. Therefore, the same members are denoted by the same reference numerals and the description thereof is omitted.

[0066] As shown in FIG. 6(b), in the displacement meter 80 according to the present embodiment, an additional condensing optical element 10 formed by at least one lens (refractive optical element) is provided between the object 2 and the image rotator 8. Thereby, compared with the displacement meter 50 according to the first embodiment shown in FIG. 6(a), the operating distance with respect to the object 2 can be increased so as to sufficiently ensure it. Note that in the displacement meter 80 according to the present embodiment, two lenses are provided as the additional condensing optical element 10 as shown in FIG. 6(b) in order to form an object-side telecentric optical system.

[0067] As described above, in the displacement meter 80 according to the present embodiment, an image rotator 8 is provided that guides light from the object 2 so as to rotate the image of the object 2 around the Z direction. Thereby, the direction of the displacement measured for the object 2 can be changed without the user changing the installation direction of the housing 40 of the displacement meter 80 according to the present embodiment.

[0068] Also, in the displacement meter 80 according to the present embodiment, an additional condensing optical element 10 is provided that guides light from the object 2 to the image rotator 8. Thereby, the working distance with respect to the object 2 can be increased.

[0069] [Method for manufacturing an article] The method for manufacturing an article according to the present embodiment includes a step of measuring the displacement amount of the object 2 using the displacement meter according to any one of the first to fourth embodiments, and a step of manufacturing the article by performing processing such as cutting, bending, or cutting on the object 2 based on the measured displacement amount. That is, it becomes possible to accurately measure the actual moving distance of the object 2 by the displacement meter according to any one of the first to fourth embodiments, and it becomes possible to manufacture an article with a small variation in length.

[0070] And, since the variation in length in the manufactured article becomes small, for example, it becomes possible to omit the step of inspecting the length of the manufactured article as a subsequent process, thereby improving the throughput. Also, since the variation in length in the manufactured article becomes small, the reliability of other devices such as automobiles into which the article is incorporated can be improved. Further, by providing a manufacturing system including the displacement meter according to any one of the first to fourth embodiments and a processing unit that processes the object 2 based on the displacement amount of the object 2 measured by the displacement meter, the reliability of the article manufactured by the manufacturing system can be improved.

[0071] Although the preferred embodiments have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof.

[0072] The disclosure of the present embodiment includes the following configurations and methods. (Configuration 1) A displacement meter comprising: an illumination unit that illuminates an object by irradiating the object with illumination light; an optical element that guides first light from the object so as to rotate an image of the object; and an imaging unit that captures an image of the object by receiving the first light passing through the optical element, and a calculation unit that calculates a displacement amount of the object between a first time and a second time from a first image captured at the first time and a second image captured at the second time by the imaging unit, wherein the optical element guides at least a part of the illumination light incident from the illumination unit to the object. (Configuration 2) The displacement meter according to Configuration 1, further comprising a holding unit that holds the optical element, wherein the holding unit has a first opening through which at least a part of the illumination light from the illumination unit passes. (Configuration 3) The displacement meter according to Configuration 2, wherein the holding unit has a second opening through which the illumination light from the optical element passes and through which the first light from the object passes, and a third opening through which the first light from the optical element passes. (Configuration 4) The displacement meter according to any one of Configurations 1 to 3, wherein the imaging unit includes an imaging element having a plurality of pixels arranged in a one-dimensional direction. (Configuration 5) The displacement meter according to Configuration 4, wherein a direction parallel to the rotation axis of the image of the object by the optical element and the arrangement direction of the plurality of pixels are perpendicular to each other. (Configuration 6) The displacement meter according to any one of Configurations 1 to 5, wherein the calculation unit calculates a displacement amount of the object in a predetermined direction within a first plane perpendicular to the rotation axis of the image of the object by the optical element. (Configuration 7) The displacement meter according to any one of Configurations 1 to 6, wherein the illumination unit illuminates a predetermined region on a predetermined surface of the object, and the imaging unit receives diffusely reflected light from the predetermined region. The displacement meter according to any one of Configurations 1 to 7, wherein the arithmetic unit calculates a displacement amount using a cross-correlation function between a first image and a second image. (Configuration 9) The displacement meter according to Configuration 8, wherein the arithmetic unit obtains a first signal by photoelectrically converting a luminance distribution in the first image, obtains a second signal by photoelectrically converting a luminance distribution in the second image, and calculates a displacement amount by calculating an extreme value of a cross-correlation function between the first signal and the second signal. (Configuration 10) The imaging unit includes an image sensor having a plurality of pixels arranged in a one-dimensional direction, and in a second plane parallel to the rotation axis of the image of the object by the optical element and the arrangement direction of the plurality of pixels, the optical axis of the illumination unit and the optical axis of the imaging unit are non-parallel to each other. The displacement meter according to any one of Configurations 1 to 9. (Configuration 11) The displacement meter according to any one of Configurations 1 to 10, wherein the imaging unit includes an image sensor and a light receiving optical system that is telecentric on the object side and guides first light from the object to the image sensor. (Configuration 12) The displacement meter according to any one of Configurations 1 to 11, wherein the optical element is rotatable around the rotation axis of the image of the object by the optical element. (Configuration 13) A control unit that performs a process of causing the imaging unit to capture images at different times and calculating a displacement amount per unit time from the images captured at different times by the arithmetic unit in a state where the optical element is arranged at each of a plurality of angles around the rotation axis of the image of the object by the optical element, and a process of determining an angle at which the displacement amount per unit time calculated by the arithmetic unit is the largest. The displacement meter according to any one of Configurations 1 to 12. (Configuration 14) The displacement meter according to any one of Configurations 1 to 13, wherein the optical element is detachably provided in the optical path of the illumination light from the illumination unit and in the optical path of the first light from the object. (Configuration 15) The displacement meter according to any one of Configurations 1 to 14, further including at least one refractive optical element that guides first light from the object to the optical element. The displacement meter according to any one of Configurations 1 to 15, wherein the optical element is a double prism. The displacement meter according to any one of Configurations 1 to 15, wherein the optical element has three reflecting surfaces. The displacement meter according to any one of Configurations 1 to 17, wherein the illumination unit includes an incoherent light source that emits illumination light. A manufacturing system comprising: the displacement meter according to any one of Configurations 1 to 18; and a processing unit that processes an object based on the amount of displacement of the object measured by the displacement meter. A method for manufacturing an article, comprising: measuring the amount of displacement of an object using the displacement meter according to any one of Configurations 1 to 18; and manufacturing an article by processing the object based on the measured amount of displacement.

Explanation of Reference Numerals

[0073] 2 Object 3 Light source (illumination unit) 4 First condenser optical element (illumination unit) 5 Second condenser optical element (imaging unit) 6 Line sensor (imaging unit) 7 Diaphragm (imaging unit) 8 Image rotator (optical element) 11 Arithmetic unit 50 Displacement meter

Claims

1. An illumination unit that illuminates an object by irradiating the object with illumination light; An imaging unit that includes an optical element that guides first light from the object so as to rotate an image of the object, and that captures an image of the object by receiving the first light that has passed through the optical element; An arithmetic unit that calculates a displacement amount of the object between the first time and the second time from a first image captured by the imaging unit at a first time and a second image captured by the imaging unit at a second time; Comprising: The displacement meter is characterized in that the optical element guides at least a part of the illumination light incident from the illumination unit to the object.

2. Comprising a holding unit that holds the optical element, The displacement meter according to claim 1, wherein the holding unit has a first opening through which at least a part of the illumination light from the illumination unit passes.

3. The displacement meter according to claim 2, wherein the holding unit has a second opening through which the illumination light from the optical element passes and through which the first light from the object passes, and a third opening through which the first light from the optical element passes.

4. The displacement meter according to claim 1, wherein the imaging unit includes an image sensor having a plurality of pixels arranged in a one-dimensional direction.

5. The displacement meter according to claim 4, wherein a direction parallel to a rotation axis of the image of the object by the optical element and an arrangement direction of the plurality of pixels are perpendicular to each other.

6. The displacement meter according to claim 1, wherein the arithmetic unit calculates the displacement amount of the object in a predetermined direction within a first plane perpendicular to a rotation axis of the image of the object by the optical element.

7. The illumination unit illuminates a predetermined region on a predetermined surface of the object, The displacement meter according to claim 1, wherein the imaging unit receives diffusely reflected light from the predetermined region.

8. The displacement meter according to claim 1, wherein the arithmetic unit calculates the displacement amount using a cross-correlation function between the first image and the second image.

9. The arithmetic unit: Acquires a first signal by photoelectrically converting a luminance distribution in the first image; Acquires a second signal by photoelectrically converting a luminance distribution in the second image; The displacement meter according to claim 8, wherein the displacement amount is calculated by calculating an extreme value of the cross-correlation function between the first signal and the second signal.

10. The imaging unit includes an imaging device having a plurality of pixels arranged in a one-dimensional direction, in a second plane parallel to the rotation axis of the image of the object by the optical element and the arrangement direction of the plurality of pixels, the optical axis of the illumination unit and the optical axis of the imaging unit are non-parallel to each other. The displacement meter according to claim 1, characterized in that.

11. The imaging unit includes an imaging device and a light receiving optical system that is telecentric on the object side and guides the first light from the object to the imaging device. The displacement meter according to claim 1, characterized in that.

12. The optical element is rotatable about the rotation axis of the image of the object by the optical element. The displacement meter according to claim 1, characterized in that.

13. A step of causing the imaging unit to capture the images at different times while the optical element is arranged at each of a plurality of angles around the rotation axis of the image of the object by the optical element, and calculating the displacement amount per unit time from the images captured at different times by the calculation unit; A step of causing the calculation unit to determine the angle at which the calculated displacement amount per unit time is the largest; A displacement meter according to claim 1, comprising a control unit that performs the steps.

14. The optical element is detachably provided in the optical path of the illumination light from the illumination unit and in the optical path of the first light from the object. The displacement meter according to claim 1, characterized in that.

15. The displacement meter according to claim 1, further comprising at least one refractive optical element that guides the first light from the object to the optical element.

16. The optical element is a double prism. The displacement meter according to claim 1, characterized in that.

17. The optical element has three reflecting surfaces. The displacement meter according to claim 1, characterized in that.

18. The illumination unit includes an incoherent light source that emits the illumination light. The displacement meter according to claim 1, characterized in that.

19. A displacement meter according to any one of claims 1 to 18; A processing unit that processes the object based on the displacement amount of the object measured by the displacement meter; A manufacturing system, characterized in that it comprises.

20. A step of measuring the displacement amount of the object using the displacement meter according to any one of claims 1 to 18; A step of manufacturing an article by processing the object based on the measured displacement amount; A method for manufacturing an article, characterized by including the above.

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