JP3728151B2 - Curved surface shape measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The curved surface shape measuring apparatus of the present invention relates to a curved surface shape measuring apparatus for measuring a curved surface shape such as a lens or a mirror with a high accuracy of, for example, 1 micrometer or less, and in particular, measuring a shape having a relatively small curvature, such as a flat mirror. Is intended for.
[0002]
[Prior art]
As a conventional curved surface shape measuring apparatus, an apparatus disclosed in Japanese Patent Laid-Open No. 05-240624 is known. 16 and 17 are diagrams showing a conventional apparatus and operation.
[0003]
The conventional apparatus has two light sources 111 a and 111 b, two light beams are applied to two places of the object 122 to be measured, and the direction of the reflected light beam is measured by the lens 116 and the position sensor 117. The object to be measured 122 is placed on the rotary table 123. The rotary table 123 is mounted on a slide table 124 that can move in one direction, and the control means controls the slide table and the rotary table so that the tangent angle of the object to be measured always falls within the measurable angle range.
[0004]
What is measured in the above measurement arrangement corresponds to the reflected light beam direction, that is, the amount of change in the tangent angle of the shape of the object to be measured. Therefore, when the data in each tilt state is integrated twice in the entire measurement section, the object to be measured The surface shape of the object can be calculated.
[0005]
[Problems to be solved by the invention]
However, the above apparatus has the following problems, and it is difficult to perform precise measurement.
[0006]
The first problem is related to the light source, which is that the measurement is sensitive to error factors such as fluctuations in the direction of the light beam generated by the light source and changes in light quantity over time. Since the conventional apparatus has two light sources, it is a factor that further increases the measurement error.
[0007]
The second problem is the complexity of the configuration, since there are two light sources, the optical configuration is complicated, and at the same time, because there is one position sensor, the light sources are alternately blinked to detect the two light beams. Therefore, complicated control such as measurement is required.
[0008]
Third, there is a problem in electrical signal detection. Even if there is only one position sensor, two signals exist for each light source. Since the detection signal of the position sensor always contains electrical noise, using two signals increases the measurement error.
[0009]
The fourth is a problem in arithmetic processing. Since there are two signals output from the position sensor, an arithmetic device that takes the difference between the two signals is required, which includes arithmetic errors and a complicated configuration.
[0010]
Fifth, there is a problem on the environment of the apparatus, and the state of gravity deformation of the object to be measured changes due to the change of the posture of the object to be measured. If the shape of the object to be measured changes during measurement, the measurement error further increases.
[0011]
The present invention has been made in view of the above problems, and a first object of the present invention is to reduce the influence of errors such as fluctuations in the amount of light given by the light source by adopting a configuration with one light source. .
[0012]
The second object of the present invention is to stabilize the traveling direction of the light beam generated by the light source and to reduce the influence of pointing stability due to the light source on the measurement error.
[0013]
A third object of the present invention is to simplify the configuration by using one output signal from the position sensor, and to reduce the influence on the measurement error caused by the electrical noise of the position sensor.
[0014]
A fourth object of the present invention is to eliminate the calculation for obtaining a difference from the signal detected by the position sensor, simplify the configuration, and eliminate errors caused by the calculation.
[0015]
The fifth object of the present invention is to stabilize the shape of the object under measurement during measurement.
[0016]
By achieving the first to fifth objects as described above, it is possible to perform highly accurate measurement of the curved surface shape.
[0017]
[Means for Solving the Problems]
A curved surface shape measuring apparatus for measuring the shape of a measurement object having a curved shape according to the present invention includes a base for setting the measurement object and a moving member movable in one direction along the measurement surface of the measurement object. And a light source that generates a single light beam as a measurement system, a corner cube that reciprocates light between the object to be measured and the measurement system, and a light detection means that detects the traveling direction of the light beam. The shape of the object to be measured is calculated from the signal of the light detection means obtained by irradiating two different positions on the object to be measured and the data of the storage device storing the position of the moving member. .
[0018]
In the present invention, when a polarizing element such as a polarizing beam splitter or a quarter-wave plate is used, the light use efficiency is increased, and high accuracy can be achieved. When using polarized light, the basic optical path arrangement is light source, polarizing beam splitter, 1/4 wavelength plate, DUT, 1/4 wavelength plate, polarizing beam splitter, corner cube, polarizing beam splitter, 1/4 wavelength The plate, the object to be measured, the quarter-wave plate, and the light detection means are arranged in this order, and information is obtained by irradiating two different places of the object to be measured through the corner cube. The obtained information is the second derivative of the shape of the object to be measured, and the shape of the object to be measured can be obtained by integrating the information twice.
[0019]
FIG. 8 and FIG. 9 specifically show the means and action in the curved surface shape measuring apparatus of the present invention. FIG. 8 is an explanatory diagram of an optical path when the surface to be measured is an ideal plane. In this figure, one parallel light beam (parallel light beam) (a) emitted from a light source (not shown) is applied to the surface to be measured at point A, and the reflected light beam (b) is reflected by a corner cube to obtain a light beam ( c) is generated. A corner cube is an optical element composed of three reflecting surfaces orthogonal to each other, and has a property of reflecting an incident light beam in the same direction as the incident direction. Therefore, the light beam (a) and the light beam (c) are parallel. The light beam (c) is reflected by the surface to be measured at a point B different from the point A to generate a light beam (d).
[0020]
Fig. 9 assumes an actual measurement surface. Although the light travels in the same way, the surface to be measured generally has different values of the inclination angles θa and θb at the points A and B. First, the light beam (b) reflected from the surface to be measured at point A is tilted by 2θa. Since the light beams (b) and (c) are parallel due to the action of the corner cube, the direction of the light beam (d) reflected from the surface to be measured at point B for the second time is inclined by θ = 2θa−2θb, and A difference in the inclination angle of point B is optically created. In order to measure the tilt angle of the light beam (d), a collimator lens is provided, and a position sensor for measuring the position of the light spot is provided at a location separated by the focal length F of the lens. Since the distance S measured by the position sensor is θF, the tilt angle of the light beam (d) can be measured from the known amount F.
[0021]
As shown in the figure, the horizontal direction is the x-axis and the vertical direction is the z-direction as shown in the figure, and the inclination difference θ between the two points is measured at various locations in the x-axis direction. Since the inclination indicates the first derivative of the shape, the difference θ between the two points of inclination corresponds to the second derivative of the shape. That is, in this arrangement, the value of the second derivative in the x direction of the shape of the object to be measured is measured, and then the shape of the object to be measured is calculated using a mathematical formula, that is, a well-known integral formula. can do.
[0022]
In this method, since the difference in inclination between two points θ = 2θa−2θb is measured, even if the two points are inclined in the same manner, they are not detected. Therefore, even if the whole object to be measured is tilted, the measurement result is not affected. Similarly, even if the entire optical system such as the light source or the corner cube is tilted, there is an advantage that the measurement result is not affected.
[0023]
In the present invention, since a measurement system can be configured using a single light beam, the influence of a change in the amount of light is automatically corrected and the structure is simple. Further, since the signal of the position sensor directly outputs the difference between the two points of inclination due to the effect of the corner cube, there is no need for an arithmetic unit for calculating the difference between the two points of inclination unlike the conventional device.
[0024]
An actual optical element has a manufacturing error, which deteriorates the quality of the light beam and causes a measurement error. Therefore, the effect of having a simple structure and a small number of elements is great. According to the present invention, the difference in inclination between two points can be detected with a small number of optical elements, so that deterioration of the quality of the light beam can be suppressed and high-precision measurement can be performed.
[0025]
FIGS. 10 and 11 show the means and action of another configuration of the present invention. FIG. 10 is an explanatory diagram of an optical path when the surface to be measured is an ideal plane.
[0026]
In the figure, (a) is a light beam emitted from a light source such as a laser (not shown). The light beam (a) has two polarization components depending on the direction of vibration of the electric field. A light beam perpendicular to the paper surface is a P wave and a light beam is horizontal to the paper surface. When the light beam (a) is incident on the polarization beam splitter (PBS), the P wave passes through as it is, and the S wave is reflected to become the light beam (b). Note that light on the P-wave side that is not used in the figure is omitted.
[0027]
The linearly polarized beam (b) in the S direction passes through the quarter-wave plate and becomes circularly polarized light, and is reflected at point A on the reflecting surface, which is the object to be measured, to become a light beam (c). The light beam (c) passes through the quarter-wave plate again and is converted from circularly polarized light into linearly polarized light whose vibration direction is P direction. The converted light beam passes through the polarization beam splitter and enters the corner cube. Since the corner cube has a property of reflecting the incident light beam in the same direction, the light beam (d) exiting the corner cube again enters the polarization beam splitter. Since the light beam (d) is P-polarized light, it passes through the polarization beam splitter, passes through the quarter-wave plate, becomes circularly polarized light, and is reflected at the point B on the reflecting surface of the object to be measured, and is reflected by the light beam (e). Become. The light beam (e) passes through the quarter-wave plate again to become linearly polarized light having the S direction of vibration, and is reflected by the polarizing beam splitter to become the light beam (f).
[0028]
Next, consider a case where the surface to be measured is not a perfect plane in the same optical path. As shown in FIG. 11, the two points A, B and B on the surface to be measured have inclination angles θa and θb with respect to the polarization beam splitter. Since the reflected light from the inclined surface has the property of changing the direction of the incident light by twice the inclination angle, the light beam (c) reflected at point A on the surface to be measured is inclined 2θa with respect to the vertical direction. The light beam (c) is reflected by the corner cube and becomes a light beam (d). Since the corner cube has the property of reflecting in the same direction as the incident beam, the light beam (d) is also inclined by 2θa with respect to the vertical direction.
[0029]
The light beam (d) is then reflected at a point B different from the point A on the surface to be measured, but the reflected light has the property of changing twice the tilt angle with respect to the incident light, so the reflected light beam (e) Is inclined by θ = 2θa−2θb with respect to the vertical axis. Therefore, if the direction of the light beam (f) is measured, the difference in inclination θ between the two points can be measured. The light beam (f) has an inclination angle θ and a positional deviation δ with respect to the optical axis as shown in the figure, but a collimator system may be configured to measure only θ. Specifically, when a collimator lens is provided as shown in the figure and a position sensor for measuring the light spot position is provided at a location separated by the focal length F of the lens, the measured distance S becomes θF, which affects the positional deviation δ. Not.
[0030]
Further, when the distance to the position sensor is long, the influence of the inclination angle θ is larger than the influence of δ, so that the collimator lens can be omitted.
[0031]
As shown in the figure, the horizontal direction is the x-axis and the vertical direction is the z-direction, and the inclination difference θ between two points is measured at various locations in the x-axis direction. Since the inclination difference θ between the two points indicates the second derivative of the shape, this arrangement measures the value of the second derivative with respect to the x direction of the shape of the object to be measured. The shape of the object can be calculated.
[0032]
Since this configuration also measures the difference between the two tilts θ = 2θa−2θb, even if the two points are tilted in the same way, the entire object to be measured, or the entire optical system such as the light source and the corner cube is tilted. The value of θ is unchanged and the measurement result is not affected. In addition, since the measurement system has a simple structure composed of one light beam and a position sensor, the output signal also directly represents the difference in inclination at two points, so that an arithmetic unit for calculating the difference in inclination is not required. The simple configuration suppresses measurement errors due to manufacturing errors that occur in actual optical elements, and enables highly accurate measurement.
[0033]
Furthermore, if this configuration is adopted, the light beam is incident on the object to be measured almost perpendicularly, so even if the distance to the object to be measured changes, the position of the light beam does not move, There are no restrictions on distance.
[0034]
FIG. 12 shows the operation in another arrangement of the present invention, and the measured surface is an ideal plane.
[0035]
In the figure, the laser oscillator, collimator lens, and position sensor, which are light sources, are fixed to the optical surface plate, and the polarizing beam splitter (PBS), corner cube (CC), and quarter-wave plate are in the x direction. It is fixed to one movable member that can be moved to the position. When the optical surface plate is tilted by φ, the light beam (f) is tilted in the direction of the light source and tilted by φ relative to the horizontal plane as shown in the figure. As a result, the light beam (f) is parallel to the optical axis of the collimator lens and forms a light spot at the center of the position sensor. This is characterized by the same result as when the optical surface plate is not inclined.
[0036]
In this arrangement, it is important that the means for measuring the tilt angle of the light beam is fixed to the same member as the light source, that is, in this case, the optical surface plate. If they are arranged on the same member, no measurement error occurs even if the optical surface plate is tilted. Similarly, no measurement error occurs even if the moving member is tilted.
[0037]
This arrangement is advantageous in reducing the size of the moving member because there are few optical systems to be fixed to the moving member.
[0038]
FIG. 13 illustrates the operation of another configuration of the present invention, and FIG. 13 shows a case where the surface to be measured is an ideal plane.
[0039]
This configuration is different from FIG. 10 in the usage of the polarization beam splitter. When a light beam (a) from a laser light source (not shown) is incident on the polarization beam splitter (PBS), the S wave is reflected (not shown) and the P wave is transmitted to become a light beam (b). When passing through the quarter-wave plate, the linearly polarized beam (b) in the P direction becomes circularly polarized light, and is reflected at point A on the reflecting surface, which is the object to be measured, to become a light beam (c). The light beam (c) passes through the quarter-wave plate again and is converted into linearly polarized light whose vibration direction is the S direction. The converted light is reflected by the polarization beam splitter and enters the corner cube. The corner cube reflects the incident light beam in the same direction as the incident light to form a light beam (d) and enters the polarization beam splitter. Since the light beam (d) is S-polarized light, the light beam (d) is reflected by the polarization beam splitter and reflected from the quarter-wave plate at the point B different from the point A by the reflecting surface, which is the object to be measured, to become the light beam (e). The light beam (e) again passes through the quarter-wave plate and becomes linearly polarized light in the P direction, passes through the polarizing beam splitter, and becomes a light beam (f). The subsequent optical paths are the same as in FIG.
[0040]
Further, the operation of another configuration of the present invention will be described with reference to FIG. This figure shows the case where the surface to be measured is an ideal plane.
[0041]
This arrangement is different from FIG. 13 in the arrangement of the optical system after the polarization beam splitter, and the whole apparatus can be made compact.
[0042]
When a light beam (a) emitted from a laser light source (not shown) enters a polarization beam splitter (PBS), an S wave is reflected (not shown) and a P wave is transmitted to become a light beam (b). After being reflected by the mirror, when passing through the quarter-wave plate, the linearly polarized beam (b) in the P direction becomes circularly polarized light, and is reflected at the point A on the reflecting surface, which is the object to be measured, to be the light beam (c). Become. The light beam (c) is again reflected from the quarter-wave plate by the mirror and converted into linearly polarized light whose vibration direction is the S direction. The converted light is reflected by the polarization beam splitter and enters the corner cube. The corner cube reflects the incident light beam in the same direction as the incident light to form a light beam (d) and enters the polarization beam splitter. Since the light beam (d) is S-polarized light, it is reflected by the polarization beam splitter, reflected by the mirror, and reflected from the quarter-wave plate at a point B different from the point A on the reflecting surface of the object to be measured. ). The light beam (e) again becomes linearly polarized light in the P direction from the quarter-wave plate through the mirror, passes through the polarizing beam splitter, and becomes the light beam (f). The subsequent optical paths are the same as in FIG.
[0043]
In still another configuration of the present invention, the movable member is rotatable, the mirror used in the previous configuration is a half mirror, and a second position sensor is provided thereafter to detect the light beam from the object to be measured. Adding a mechanism for rotating the moving member so that the output value from the second position sensor is constant, and controlling the light beam so that it always points in a certain direction, for example, the normal direction with respect to the object to be measured. Is a feature. By adopting such a configuration, it is possible to follow the change in tilt even for an object to be measured having a large error such that the light beam goes out of the measurable region, so that the light beam to be detected falls within the measurable region. And the range of shape measurement of the object to be measured can be expanded. In addition, since this configuration does not change the posture of the object to be measured, the direction of the gravity vector does not change, and the deformation state of the object to be measured due to the gravity is kept constant. Therefore, the shape of the object to be measured does not change during measurement, and the measurement accuracy can be improved.
[0044]
In this apparatus, since the change in the direction of the light beam of the light source affects the measurement result, the stability of the light traveling direction from the light source, that is, pointing stability is important. However, a light source such as a laser oscillator has a pointing stability error due to factors such as thermal stability. For this reason, if the light from the light source is not used directly but is emitted after passing through the single mode optical fiber, the pointing stability can be stabilized. The reason is that the exit end of the optical fiber has an exit region size of only a few microns, and can be treated as a point light source. Furthermore, the light emitted from the semiconductor laser has unevenness in light intensity depending on the emission direction due to the influence of diffraction or the like. This is also a phenomenon caused by the fact that the emission area is not sufficiently small. Therefore, it is improved by using a single mode optical fiber, and the measurement accuracy is improved.
[0045]
Instead of using a single mode optical fiber, the light traveling direction can be stabilized even if the light from the light source is once condensed on a pinhole mask having a small opening and then emitted. The reason is that at the exit end of the pinhole mask, the size of the exit area is small, so that it can be handled almost as a point light source. Furthermore, the light intensity unevenness due to the direction of the emitted light from the semiconductor laser can be improved by using a pinhole mask having a sufficiently small emission area, and the measurement accuracy can be improved.
[0046]
In the present invention, a position sensor is used as an optical sensor for detecting the incident position of the light beam as the detecting means for the direction of travel of the light beam. In simple position detection, the angle at which the light beam travels cannot be distinguished from the parallel movement of the light beam. However, if the shape error of the object to be measured is small, the translational component of the light beam is small and can be ignored. The traveling direction of the light beam can be detected with a simple configuration.
[0047]
A lens and a position sensor disposed at its focal position are used as detection means for detecting a more precise angle of travel of the light beam. As is apparent from geometrical optics, if the focal length of the lens is F and the angle of travel of the light beam is θ, the parallel light beam of the angle θ incident on the lens is Fθ from the optical axis center regardless of the translation component. Focus on distance. This action enables more precise shape measurement.
Further, as the optical element used in the present invention, a roof mirror (b) shown in FIG. 15 can be used instead of the corner cube (a). The roof mirror is composed of two reflecting surfaces orthogonal to each other, and when observed from the direction along the ridgeline, the incident light and the reflected light have the property of being parallel, and therefore can be applied to the present invention. In general, it is difficult to process the vicinity of the ridgeline, and when this portion is exposed to light, performance degradation occurs and shape measurement accuracy is deteriorated. The corner cube has three ridgelines, but the roof mirror has two ridges, and the layout without using the ridgelines is simple, so that the measurement accuracy can be improved.
[0048]
In addition, since the roof mirror can be obtained at a lower cost than the corner cube, it is possible to reduce the cost of the apparatus.
[0049]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a curved surface shape measuring apparatus according to Embodiment 1 of the present invention.
[0050]
In the figure, reference numeral 1 denotes an object to be measured which is fixed to the base 2. The DUT 1 has a shape close to a plane, and the cross-sectional direction to be measured is the x-axis direction, and the normal direction of the surface to be measured perpendicular to the x-axis is the z-axis. A guide 4 is fixed to the base 2 via a spacer 3. The guide 4 is provided with an x-axis moving member 5 that is parallel to the x-axis direction and can be moved in the x-axis direction by the guide 4. A measuring head housing 6 is fixed to the x-axis moving member 5. A semiconductor laser 7 is fixed to the housing 6.
[0051]
The light from the semiconductor laser 7 is guided to a single mode optical fiber 8 and emits a light beam from an emission end 9 fixed to the housing 6. The emitted light beam is guided to the lens 10 fixed to the housing 6 while gradually spreading by diffraction, and becomes a substantially parallel light beam (a). The change in pointing stability of the light beam affects the measurement result, but it is an important item. However, instead of directly using the light from the semiconductor laser, the light travels once it passes through a single mode optical fiber. The direction can be stabilized. The reason is that the size of the area emitted from the emission end 9 of the optical fiber is only a few microns, and can be handled as a point light source, so the influence of pointing stability, which is one of the errors of the laser, can be eliminated.
[0052]
Furthermore, the light emitted from the semiconductor laser has uneven light intensity depending on the direction of emission due to the influence of diffraction or the like. The influence of the unevenness can also be improved by using a single mode optical fiber because the emission region can be made sufficiently small.
[0053]
The light beam (a) is guided to the surface to be measured and reflected to become the light beam (b). The light beam (b) reflected by the surface to be measured is guided to a corner cube 13 fixed to the housing 6 and reflected by the corner cube to become a light beam (c). The light beam (c) is re-entered at a different position on the surface to be measured, and the reflected light beam (d) is collected by the collimator lens 15 and is separated from the lens 15 by the focal length F on the housing 6. A focal point is formed on a fixed position sensor (light spot position detecting means) 14. A position sensor is a kind of semiconductor element that outputs an electrical signal corresponding to the incident position of light. The signal output from the position sensor 14 is the position of the light beam (f) with respect to the case where the shape error of the surface to be measured is zero, that is, the deviation from the optical axis 16. The position sensor 14 and the moving member 5 are connected to the control device 20.
[0054]
FIG. 2 shows a flowchart for measuring the tilt deviation of the object to be measured using the configuration of FIG. First, the DUT 1 is attached to the base 2 (101), and the moving member 5 is moved to an initial position, for example, x = 0 (102). Next, the moving member 5 is scanned along the x-axis while recording the electrical signal output from the position sensor 14 and the position of the moving member 5. As described in “Means and Actions for Solving the Problems”, since the electrical signal is an optically created difference between the tilt angles of the two incident points with respect to the object to be measured, it is x This is the value of the second derivative of the shape of the object to be measured at each position on the axis. If the second derivative is known, the shape of the object to be measured can be calculated by integrating the measured values (103). When the scan is completed, the object to be measured is removed (104) and integrated to calculate the shape (105).
[0055]
This embodiment has the following effects compared with the conventional curved surface measuring apparatus.
1) High margin for parts and assembly accuracy. That is, since the light source and the light detector are configured on the same member, even if the housing 6 of the measuring head tilts, the difference in tilt between the two points of the object to be measured does not change. The measurement results are the same. Therefore, even if the accuracy of the guide 4 is poor and the error in moving the housing 6 is large, it is not affected by these and high-precision shape measurement is possible.
2) Since there is only one light source and position sensor (light spot position detecting means), the number of components can be reduced and the cost can be reduced.
3) Since a single mode optical fiber is used, light emitted from the end face can be regarded as a point light source, and a homogeneous light beam with improved light intensity unevenness and pointing stability caused by the light source can be obtained. it can.
4) Since the object to be measured is fixed to the base during measurement, the direction of the gravity vector applied to the object to be measured is constant, and the deformed state is maintained, and highly accurate shape measurement is possible.
5) Since the difference in inclination between the two points is optically generated, a conventional arithmetic device is not required, and highly accurate shape measurement is possible.
6) Since it is composed of a small number of optical components, the influence of manufacturing errors of the optical components can be reduced, and highly accurate shape measurement can be performed.
[0056]
In FIG. 1, the semiconductor laser 7 as a light source is fixed to the moving housing 6, but the optical fiber 8 is flexible, so the semiconductor laser 7 is attached to a non-moving member and wired to the emitting end 9 of the moving member with the optical fiber. It is also possible to configure. However, with this configuration, the shape of the optical fiber changes greatly with the movement of the moving member, and the amount of light at the exit end changes.
[0057]
FIG. 3 shows a curved surface shape measuring apparatus according to the second embodiment of the present invention, in which the configuration of the system is enhanced by using polarized light.
[0058]
In the figure, reference numeral 1 denotes an object to be measured which is fixed to the base 2. The DUT 1 has a shape close to a plane, and the cross-sectional direction to be measured is the x-axis direction, and the normal direction of the surface to be measured perpendicular to the x-axis is the z-axis. A guide 4 is fixed to the base 2 via a spacer 3. The guide 4 is provided with an x-axis moving member 5 which is parallel to the x-axis direction and can be moved in the x-axis direction by the guide 4. A measuring head housing 6 is fixed to the x-axis moving member 5, and a semiconductor laser 7 is fixed to the housing 6.
[0059]
The light from the semiconductor laser 7 is guided to a single mode optical fiber 8 and emits a light beam from an emission end 9 fixed to the housing 6. The emitted light beam is guided to the lens 10 fixed to the housing 6 while gradually spreading by diffraction, and becomes a substantially parallel light beam (a). Rather than directly using the light of the semiconductor laser, the light traveling direction can be stabilized by passing the light through the single mode optical fiber and then emitting it. Effects such as pointing stability using a single mode optical fiber are the same as in the previous embodiment.
[0060]
In this embodiment, the polarizing beam splitter 11 is fixed to the housing 6 and the light beam (a) is guided to the polarizing beam splitter 11. The polarization beam splitter 11 passes the P wave, reflects the S wave, and forms a light beam (b). In FIG. 3, the P wave that has passed is not shown because it is not used.
[0061]
The light beam (b) passes through a quarter-wave plate 12 fixed to the housing 6 and is converted into circularly polarized light. It becomes. The light beam (c) again passes through the quarter-wave plate 12 to become P-wave linearly polarized light, passes through the polarizing beam splitter 11 and is bent by the corner cube 13 fixed to the housing 6, and the light beam (d ). Next, the light beam (d) passes through the polarization beam splitter 11, passes through the quarter-wave plate 12, becomes circularly polarized light, and enters and returns to the different positions on the surface 1 to be measured almost perpendicularly, thereby reflecting the light beam (e ). The light beam (e) passes through the quarter-wave plate 12 again and is converted into S-wave linearly polarized light, and is reflected by the polarization beam splitter 11 to become a light beam (f). The light beam (f) is incident on the position sensor 14 fixed to the housing 6. The output signal of the position sensor 14 is the position of the light beam (f) with respect to the case where the shape error of the measured surface is zero, that is, the deviation from the optical axis 16.
[0062]
Since the output of the position sensor reflects the inclination angle of the light beam (f) and represents the difference in inclination angle at two points on the surface to be measured, it corresponds to the second derivative of the shape of the object to be measured. Further, if the distance to the position sensor is increased, the influence of the positional deviation of the light beam (f) is reduced.
[0063]
The signals of the moving member 5 and the position sensor 14 are connected to the control device 20.
[0064]
In this configuration as well, the tilt deviation of the object to be measured is measured according to the flowchart shown in FIG.
[0065]
First, the DUT 1 is attached to the base 2 (101), and the moving member 5 is moved to an initial position, for example, x = 0 (102). Next, the moving member 5 is scanned along the x-axis while recording the electrical signal output from the position sensor 14 and the position of the moving member 5. Since the electrical signal corresponds to the second derivative of the shape of the object to be measured, the measured value indicates the value of the second derivative of the shape of the object to be measured at each position on the x axis. If the second derivative is known, the measured value can be integrated twice to calculate the shape of the object to be measured (103). When the scan is completed, the object to be measured is removed (104) and integrated to calculate the shape (105).
[0066]
This embodiment has the following effects in addition to the effects of the first embodiment. In the first embodiment, since the light beam is incident on the object to be measured with an inclination, when the distance to the object to be measured changes, the position of the light beam changes, and when the distance to the object to be measured changes greatly, There is a problem that the light beam deviates from the measurable region. In this embodiment, since the light beam is incident on the surface of the object to be measured substantially perpendicularly, the position of the light beam does not move even if the distance to the object to be measured changes, and the distance to the object to be measured. There are no restrictions on
[0067]
In FIG. 3, it has been described that the light beam (a) is made into a parallel light beam by the lens 10, but if the position and curvature of the lens are adjusted so as to focus at the position of the position sensor, the position measurement accuracy of the position sensor can be improved. The tilt error can be measured with higher accuracy.
[0068]
FIG. 4 shows a third embodiment of the curved surface shape measuring apparatus according to the present invention, in which the detection of the light beam is further improved in addition to the second embodiment.
[0069]
3 is similar to FIG. 3, the DUT 1 having a shape close to a plane is fixed to the base 2, the direction of the cross section to be measured is the x-axis direction, and the normal direction of the surface to be measured is perpendicular to the x-axis Is the z-axis. The base 2 is provided with a guide 4 parallel to the x-axis direction via a spacer 3, and an x-axis moving member 5 that can be moved in the x-axis direction by the guide 4. A measuring head housing 6 is fixed to the x-axis moving member 5, and a semiconductor laser 7 is fixed to the housing 6.
[0070]
The light from the semiconductor laser 7 is guided to the single mode optical fiber 8 and is emitted from the emission end 9 fixed to the housing 6 and becomes a substantially parallel light beam (a) by the lens 10 fixed to the housing 6. The reason for the emission after passing through the single mode optical fiber and the effect are the same as in the previous two embodiments.
[0071]
The light beam (a) is incident on the polarization beam splitter 11 fixed to the housing 6. The polarization beam splitter 11 passes the P wave (not shown since it is not used hereafter), reflects the S wave, and forms a light beam (b). The light beam (b) passes through a quarter-wave plate 12 fixed to the housing 6 and becomes circularly polarized light. The light beam (b) enters and reflects almost perpendicularly to the surface to be measured 1 to become a light beam (c). The light beam (c) is again converted into P-wave linearly polarized light by the quarter-wave plate 12, passes through the polarizing beam splitter 11, and is folded by the corner cube 13 fixed to the housing 6. The light beam (d) It becomes. The light beam (d) passes through the polarization beam splitter 11 and the quarter-wave plate 12, enters and reflects almost perpendicularly to the measurement surface 1, and becomes a light beam (e). The light beam (e) passes through the quarter-wave plate 12 again and is converted into S-wave linearly polarized light, and is reflected by the polarization beam splitter 11 to become a light beam (f). A feature of this embodiment is that the light beam (f) is incident on the lens 15 fixed to the housing 6.
[0072]
A position sensor 14 fixed to the housing 6 is provided at the focal position of the lens 15 to measure the position of the condensed light beam. Since the position sensor 14 is disposed at the focal position of the lens 15 having the focal length F, the output signal is Fθ when the inclination in the traveling direction of the light beam (f) is θ. That is, in the arrangement of FIG. 4, only the tilt component of the light beam (f) can be extracted and detected, leading to higher accuracy.
[0073]
The output signal of the position sensor 14 also corresponds to a deviation from the optical axis 16 at the position of the light beam (f) with respect to the case where the shape error of the measured surface is zero. Since the output signal of the position sensor represents the difference in inclination angle between two points on the surface to be measured, it corresponds to the second derivative of the shape of the object to be measured. The position sensor 14 and the moving member 5 are connected to the control device 20.
[0074]
Also in this configuration, as in the first and second embodiments, the apparatus scans the moving member 5 along the x axis while recording the electric signal output from the position sensor 14 and the position of the moving member 5. Since the output electric signal corresponds to the second derivative of the shape, the measured value becomes the second derivative value of the shape of the object to be measured at each position on the x axis, and the shape of the object to be measured is integrated by the measured value. Can be calculated.
[0075]
In addition to the effects described in the second embodiment, the present embodiment can measure the inclination angle of the light beam (f) separately from the positional deviation, so that the measurement surface has a large shape error or the movement accuracy of the moving member is high. Even if the positional deviation of the light beam (f) becomes large, the measurement is not affected by the deviation and high-precision measurement is possible.
[0076]
FIG. 5 shows a fourth embodiment of the curved surface shape measuring apparatus according to the present invention, in which the arrangement of the optical elements of the measuring system is devised to make the apparatus more compact.
[0077]
In the figure, reference numeral 1 denotes an object to be measured which is fixed to the base 2. The DUT 1 has a shape close to a plane, and the cross-sectional direction to be measured is the x-axis direction, and the normal direction of the surface to be measured perpendicular to the x-axis is the z-axis. A guide 4 is fixed to the base 2 via a spacer 3. The guide 4 is provided in parallel to the x-axis direction, and an x-axis moving member 5 that is movable in the x-axis direction by the guide 4 is provided.
[0078]
A measuring head housing 6 is fixed to the x-axis moving member 5. Further, an optical surface plate 17 is provided on a member that does not move in FIG. 5 while being fixed to the spacer 3, and the semiconductor laser 7 is fixed to the surface plate 17 side. The light from the semiconductor laser 7 is guided to the single mode optical fiber 8 and the light beam is emitted from the emission end 9 fixed to the optical surface plate 17. The emitted light beam is guided to the lens 10 fixed to the optical surface plate 17 while gradually spreading by diffraction, and becomes a substantially parallel light beam (a). The reason for using the single mode optical fiber is the same as in the previous embodiment.
[0079]
In this embodiment, the polarization beam splitter 11 is fixed to the housing 6 on the moving member side, and the light beam (a) is guided to the polarization beam splitter 11. The polarization beam splitter 11 passes the P wave and reflects the S wave to form a light beam (b). In FIG. 5, the P wave side not used is not shown. The light beam (b) passes through a quarter-wave plate 12 fixed to the housing 6 and becomes circularly polarized light. The light beam (b) enters and reflects almost perpendicularly to the measured surface 1 to become a light beam (c). . The light beam (c) passes through the quarter-wave plate 12 again, is converted into P-wave linearly polarized light, passes through the polarizing beam splitter 11, and is bent by the corner cube 13 fixed to the housing 6. Beam (d). The light beam (d) passes through the polarizing beam splitter 11 and the quarter-wave plate 12, and enters and reflects at different points on the surface 1 to be measured almost perpendicularly to become the light beam (e). The light beam (e) passes through the quarter-wave plate 12 again to be converted into S-wave linearly polarized light, is reflected by the polarization beam splitter 11, becomes a light beam (f), and is fixed to the optical surface plate 17. The light enters the lens 15.
[0080]
A position sensor 14 fixed to the optical surface plate 17 is provided at the focal position of the lens 15 to measure the position of the condensed light beam. The output signal of the position sensor 14 is the position of the light beam (f) with respect to the case where the shape error of the surface to be measured is zero, that is, the deviation from the optical axis 16. The output signal of the position sensor is the difference between the tilt angles of the two points on the measured surface and corresponds to the second derivative of the shape. The position sensor 14 and the moving member 5 are connected to the control device 20.
[0081]
In this configuration, as in the first embodiment, the measurement is performed by scanning the moving member 5 along the x-axis while recording the electric signal output from the position sensor 14 and the position of the moving member 5. Since the electrical signal corresponds to the second derivative of the shape, this apparatus measures the value of the second derivative of the shape of the object to be measured at each position on the x axis. If the second derivative is known, the measured value is integrated to calculate the shape of the object to be measured.
[0082]
The present embodiment has the following effects in addition to the effects described in the third embodiment.
1) Since there is no semiconductor laser or lens in the moving member, the moving member can be made small.
2) Since an optical system such as a semiconductor laser is attached to a non-moving member instead of a moving member, high-accuracy measurement can be performed without being affected by vibrations generated when the moving member moves.
[0083]
In particular, since the optical fiber is weak in structure, it is easily deformed by disturbance vibration, and when it is deformed, the optical path passing therethrough is changed, so that the light beam emitted from the emission end is also affected, and the quality deteriorates. In this embodiment, since the main optical element is fixed to a member that does not move,
High-precision shape measurement is possible without worrying about quality deterioration.
[0084]
FIG. 6 is a diagram showing a configuration in which the apparatus can be made more compact in Embodiment 5 of the curved surface shape measuring apparatus of the present invention.
[0085]
In this figure, the DUT 1 is fixed to the base 2 in a shape close to a plane, and the direction of the measurement cross section is the x-axis direction, and the normal direction of the surface measured perpendicular to the x axis is the z-axis. A guide 4 provided in parallel to the x-axis direction is fixed to the base 2 via a spacer 3. Further, an x-axis moving member 5 that is movable in the x-axis direction by the guide 4 is provided.
[0086]
A measuring head housing 6 is fixed to the x-axis moving member 5. Further, in the case of FIG. 6, an optical surface plate 17 is provided fixed to the spacer 3 in the case of FIG. 6, and the semiconductor laser 7 is fixed to the surface plate 17. The light from the semiconductor laser 7 is guided to the single mode optical fiber 8 as in the previous embodiment, and the light beam is emitted from the emission end 9 fixed to the optical surface plate 17. The emitted light beam is guided to the lens 10 fixed to the optical surface plate 17 while gradually spreading by diffraction, and becomes a substantially parallel light beam (a).
[0087]
In this embodiment, the light beam (a) is guided to the polarization beam splitter 11 fixed to the optical surface plate 17. The polarization beam splitter 11 reflects the S wave and passes the P wave. In FIG. 6, the reflected light beam on the S wave side is not shown because it is not used. The P wave that has passed through the polarization beam splitter 11 is reflected by a mirror 18 fixed to the housing 6 on the moving member 5 to become a light beam (b). The light beam (b) passes through a quarter-wave plate 12 fixed to the housing 6 and becomes circularly polarized light. The light beam (b) enters and reflects almost perpendicularly to the surface to be measured 1 to become a light beam (c). The light beam (c) passes through the quarter-wave plate 12 again to become S-wave linearly polarized light, and is a mirror. 18 Then, the light is reflected by the polarizing beam splitter 11 and bent by the corner cube 13 fixed to the optical surface plate 17 to be a light beam (d). The light beam (d) is further reflected by the polarization beam splitter 11 and is mirrored. 18 The light passes through the quarter-wave plate 12 and enters and reflects almost perpendicularly to the surface to be measured 1 to become a light beam (e). The light beam (e) passes through the quarter-wave plate 12 again and is converted into P-wave linearly polarized light, and then the mirror. 18 The light is reflected by the light beam (f), passes through the polarization beam splitter 11, and enters the lens 15 fixed to the optical surface plate 17.
[0088]
A position sensor 14 fixed to the optical surface plate 17 is provided at the focal position of the lens 15 to measure the position of the condensed light beam. The output signal of the position sensor 14 is the position of the light beam (f) with respect to the case where the shape error of the measured surface is zero, that is, the deviation from the optical axis 16. The output signal of the position sensor is a tilt component of the light beam (f), which represents the difference in tilt between two points on the surface to be measured, and corresponds to the second derivative of the shape. The position sensor 14 and the moving member 5 are connected to the control device 20.
[0089]
Also in this configuration, the measurement is performed by scanning the moving member 5 along the x axis while recording the output signal of the position sensor 14 and the position of the moving member 5. Since this apparatus measures the value of the second derivative of the shape of the object to be measured at each position on the x-axis, the shape of the object to be measured can be calculated by integrating the measured values.
[0090]
In this example, in addition to the effects described in the fourth embodiment, there is no semiconductor laser or lens, and no polarization beam splitter or corner cube on the moving member side, so that the moving member can be configured more compactly.
[0091]
As a modification of the present embodiment, a configuration in which the position of the quarter-wave plate 12 is changed between the polarization beam splitter and the mirror is also conceivable. In the case of this configuration, since the mirror 18 is used in a circularly polarized state with an incidence of 45 degrees, it is very important to have the same reflectance for both the S wave and the P wave. If the reflectivity is different, circularly polarized light becomes elliptically polarized light, and when reflected from the object to be measured and incident on the quarter-wave plate again, it does not become linearly polarized light orthogonal to the original state, but the light from the polarizing beam splitter 11 This is because the separation is incomplete and causes a measurement error. The operation of the other optical systems is the same as in the previous embodiment.
[0092]
FIG. 7 shows Embodiment 6 of the curved surface shape measuring apparatus of the present invention.
[0093]
In the figure, the DUT 1 has a shape close to a plane and is fixed to the base 2. The direction of the cross section to be measured is the x-axis direction, and the normal direction of the surface to be measured perpendicular to the x-axis is the z-axis. A guide 4 parallel to the x-axis direction is fixed to the base 2 via a spacer 3, and an x-axis moving member 5 that is movable in the x-axis direction by the guide 4 is provided.
[0094]
The x-axis moving member 5 is provided with a rotary table 21, and the measurement head housing 6 is fixed to the rotary table 21. Further, an optical surface plate 17 is provided fixed to the non-moving member, that is, the spacer 3 in FIG. 7, and the semiconductor laser 7 is fixed to the surface plate 17. The light from the semiconductor laser 7 is guided to the single mode optical fiber 8 and the light beam is emitted from the emission end 9 fixed to the optical surface plate 17. The emitted light beam is guided to the lens 10 fixed to the optical surface plate 17 while gradually spreading by diffraction, and becomes a substantially parallel light beam (a).
[0095]
The light beam (a) is guided to a polarization beam splitter 11 fixed to the optical surface plate 17. The polarization beam splitter 11 reflects the S wave and passes the P wave. In FIG. 7, the reflected S-wave side light beam is not shown because it is not used.
[0096]
The P wave that has passed through the polarization beam splitter 11 is reflected by a half mirror 22 fixed to the housing 6 to become a light beam (b). The half mirror 22 is a mirror having a reflectance of less than 100% and transmits part of incident light. The light on the transmission side that is not used in the figure is omitted. The light beam (b) passes through a quarter-wave plate 12 fixed to the housing 6 and becomes circularly polarized light. The light beam (b) enters and reflects almost perpendicularly on the measurement surface 1 to become a light beam (c). When the light beam (c) passes through the quarter-wave plate 12 again, it becomes S-wave linearly polarized light and is reflected by the half mirror 22. At this time, the light transmitted through the half mirror 22 enters the second position sensor 19 fixed to the housing 6.
[0097]
On the other hand, the light reflected by the half mirror 22 is reflected by the polarization beam splitter 11 and is bent by the corner cube 13 fixed to the optical surface plate 17 to become a light beam (d). The light beam (d) is reflected by the polarizing beam splitter 11, reflected by the half mirror 22, passes through the quarter-wave plate 12 and becomes circularly polarized light, and enters and reflects almost perpendicularly to different points on the measured surface 1. To become a light beam (e). The light beam (e) is again converted into P-wave linearly polarized light through the quarter-wave plate 12 and then reflected by the half mirror 22 to become a light beam (f), which passes through the polarization beam splitter 11 and is optical. The light enters the lens 15 fixed to the surface plate 17.
[0098]
A position sensor 14 fixed to the optical surface plate 17 is provided at the focal position of the lens 15 to measure the position of the condensed light beam. The output signal of the position sensor 14 reflects the tilt component of the light beam (f) by the position of the light beam (f) when the shape error of the measured surface is zero, that is, the deviation from the optical axis 16. This corresponds to the difference in inclination angle between two points on the surface to be measured, that is, the second derivative of the shape. The position sensor 14, the second position sensor 19, the rotary table 21, and the moving member 5 are connected to the control device 20.
[0099]
The present embodiment is characterized in that the measurement is performed by controlling the rotary table 21 so that the signal of the second position sensor becomes constant. By making the signal of the second position sensor constant, the direction of the light beam reflected from the object to be measured can be made constant.
[0100]
The measurement of the object to be measured is performed by scanning the moving member 5 along the x axis while recording the electrical signal output from the position sensor 14 and the position of the moving member 5. Since the output of this apparatus is the measurement of the second derivative of the shape of the object to be measured at each position on the x-axis, the shape of the object to be measured can be calculated by integrating the measured values.
[0101]
In the present embodiment, in addition to the effects described in the fifth embodiment, there is an effect that the direction of the light beam applied to the object to be measured can be always constant. Therefore, even when the shape error of the object to be measured is large, the reflected light is not greatly shifted and the measurable range is not narrowed.
[0102]
In the embodiment described above, a semiconductor laser is guided to a single mode optical fiber to obtain a point light source. The same effect can be obtained using a condensing lens and a pinhole. However, since this is an optical system that requires more time for alignment than a fiber that can be flexibly wired, extra cost and adjustment time are required.
[0103]
Further, as a specific driving means of the moving member 5, since the error of the guide does not affect the measurement result, the combination of the rolling type linear motion guide and the ball screw is appropriate from the viewpoint of cost. A component such as a motor capable of highly accurate positioning may be used.
[0104]
In the measurement sequence, the object to be measured can be attached / detached. However, when the same object to be measured is always measured, the steps (102) and (104) for attaching / detaching the object to be measured in the flowchart of FIG. 2 are not necessary.
[0105]
In each embodiment, a corner cube is used as an optical element. However, instead of the corner cube, a roof mirror, that is, a triangular prism having two surfaces orthogonal to each other may be used. This is because the roof mirror has the property that the incident light and the reflected light become parallel when observed from the direction along the ridgeline due to the effect of two reflecting surfaces orthogonal to each other. The vicinity of the ridge line is generally difficult to process, which causes the shape measurement accuracy to deteriorate. The corner cube has three ridge lines, but the roof mirror has two ridge lines, and the layout that does not use the ridge lines is simple. Therefore, the effect of improving the measurement accuracy can be obtained.
[0106]
【The invention's effect】
As described above, the curved surface shape measuring apparatus of the present invention includes a base for setting an object to be measured, and a movable member that can move in one direction along the surface to be measured of the object to be measured. A light source that generates a single light beam, a corner cube, and a light detection means that detects the traveling direction of the light beam, and irradiates the light beam from the light source at two different positions on the object to be measured. It has a basic configuration having a calculation control device for calculating the shape of the object to be measured from the obtained signal of the light detection means and the data of the storage device for storing the position of the moving member. The following effects are obtained with respect to the curved surface shape measuring apparatus. ,
1) Since the light source and the photodetector are configured on the same member in the basic configuration, the measurement result is not affected by the posture error of the moving member, and highly accurate shape measurement is possible.
2) Since the object to be measured is fixed to the base during measurement, the direction of the gravity vector applied to the object to be measured is always constant and the deformed state is maintained, so that highly accurate shape measurement is possible.
3) Since the light source is constituted by one, the influence of the fluctuation of the direction of the light beam generated by the light source and the light amount change error can be minimized.
4) Since the position sensor (light spot position detecting means) is composed of one, the influence of the position detection error of the position sensor can be minimized.
5) Since the difference in inclination between the two points is optically generated, a conventional arithmetic device is not required, and highly accurate shape measurement is possible.
6) Since it is composed of a small number of optical components, the influence of manufacturing errors of the optical components can be reduced, and highly accurate shape measurement can be performed.
7) Since there are only one light source and position sensor and there are few components of the optical system, the apparatus configuration can be simplified and the cost can be reduced.
[0107]
In addition, if the configuration using polarized light is used with respect to the basic configuration, the detection light beam is incident on the object to be measured almost perpendicularly, so even if the distance to the object to be measured changes, the position of the light beam does not move, A restriction on the distance to the object to be measured can be eliminated, and the degree of freedom in arrangement can be increased.
[0108]
There are various configurations in which the optical member of the measurement optical system is distributed to the surface plate side and the moving member side. However, the moving member can be made smaller as the optical system fixed to the moving member is reduced. At this time, it may be necessary to pay attention to the deterioration of the light beam quality due to the vibration caused by the movement of the moving member. However, if the optical fiber is arranged on the fixed member, the light beam quality is improved. And high-precision measurement is possible.
[0109]
Also, when a rotation function is added to the moving member side
1) Since the direction of the light beam applied to the object to be measured can be made constant at all times, even when the shape error of the object to be measured is large, the reflected light is prevented from being greatly shifted and the measurable range is narrowed. The range of application related to is expanded.
2) Since the orientation of the object to be measured does not change, the direction of the gravity vector is constant, so that the deformation state of the object to be measured due to gravity is maintained, the shape does not change during measurement, and the measurement accuracy can be improved.
There is an effect.
[0110]
In addition, using a single-mode optical fiber for each optical element, the light emitted from the end face can be regarded as a point light source, so a uniform light beam with improved light intensity unevenness and pointing stability caused by the light source. Thus, highly accurate shape measurement can be performed.
[0111]
Even with a configuration using a pinhole mask instead of a single mode fiber, light emitted from the pinhole mask can be regarded as almost a point light source, which improves light intensity unevenness and pointing stability caused by the light source. A homogeneous light beam is obtained, and highly accurate shape measurement is possible.
[0112]
As for the detection system, the detection means for the direction of travel of the light beam is configured only by the position sensor, and a certain accuracy can be obtained with a simple configuration. However, if a position sensor is arranged at the focal position of the lens using a lens system, Since the traveling direction of the light beam can be detected separately from the translation component of the beam, the measurement accuracy is improved. This configuration is particularly effective when the movement error of the moving member, the shape error of the object to be measured are large, and the parallel movement component of the light beam is large.
[0113]
For corner cubes, inexpensive roof mirrors can be used as an alternative. Since the roof mirror can reduce the possibility of the light beam hitting a ridge line with deteriorated characteristics, the measurement can be performed with high accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram showing a curved surface shape measuring apparatus according to Embodiment 1 of the present invention;
FIG. 2 is a flowchart showing Embodiment 1 of the present invention;
FIG. 3 is a view showing a curved surface shape measuring apparatus according to Embodiment 2 of the present invention;
FIG. 4 is a view showing a curved surface shape measuring apparatus according to Embodiment 3 of the present invention;
FIG. 5 is a view showing a curved surface shape measuring apparatus according to Embodiment 4 of the present invention;
FIG. 6 is a view showing a curved surface shape measuring apparatus according to Embodiment 5 of the present invention;
FIG. 7 is a view showing a curved surface shape measuring apparatus according to Embodiment 6 of the present invention;
FIG. 8 is a first diagram illustrating an optical path in the present invention;
FIG. 9 is a first diagram illustrating the operation in the present invention;
FIG. 10 is a second diagram illustrating an optical path in the present invention;
FIG. 11 is a second diagram illustrating the operation of the present invention.
FIG. 12 is a diagram for explaining the operation in the present invention.
13 is a diagram for explaining the operation in the present invention, FIG.
FIG. 5 is a diagram for explaining the operation in the present invention.
FIG. 15 is an explanatory diagram of the shape of a mirror used in the present invention;
FIG. 16 is an explanatory diagram of a conventional curved surface shape measuring apparatus;
FIG. 17 is a diagram for explaining the operation of a conventional curved surface shape measuring apparatus;
[Explanation of symbols]
1 DUT,
2 base,
3 Spacer,
4 guides,
5 x-axis moving member,
6 Measuring head housing,
7 Semiconductor laser element,
8 single-mode optical fiber,
9 Optical fiber exit end,
10 lenses,
11 Polarizing beam splitter,
12 quarter wave plate
13 Corner cube,
14 position sensor,
15 lenses,
16 optical axes,
17 Optical surface plate,
18 mirrors,
19 Second position sensor,
20 control unit,
21 rotating table,
22 half mirror,
51 Y slide,
52 X slides,
53 Z slide

Claims (12)

In a curved surface shape measuring apparatus for measuring the shape of a measurement object having a curved surface, the apparatus includes a base for setting the measurement object, and a movement movable in one direction along the measurement surface of the measurement object. is composed of a member, and the light detection means to the mobile member for detecting the direction of travel of the light source and the corner cubes and the light beam for generating a single light beam as a measuring system, the optical path of the measurement system is a light source, The object to be measured, the corner cube, the object to be measured, and the light detection means are arranged in this order, and two different places of the object to be measured are irradiated through the corner cube detected by the light detection means. resulting signal and from a data storage device for storing the position of the moving member, the curved surface shape measuring apparatus characterized by having a calculation control unit for calculating the shape of該被measured. In a curved surface shape measuring apparatus for measuring the shape of a measurement object having a curved shape, the apparatus includes a base for setting the measurement object and a movable member movable in one direction along the measurement surface of the measurement object It is composed of a light source in the moving member for generating a single light beam as a measurement system, a polarization beam splitter, 1/4-wave plate, and a light detecting means for detecting the direction of travel of the corner cube, and light beam However , the optical path of the measurement system is a light source, a polarizing beam splitter, a 1/4 wavelength plate, an object to be measured, a 1/4 wavelength plate, a polarizing beam splitter, a corner cube, a polarizing beam splitter, a 1/4 wavelength plate, an object to be measured. A quarter- wave plate, and a light detection means, and a signal obtained by irradiating two different parts of the object to be measured via the corner cube detected by the light detection means; , The position of the moving member A curved surface shape measuring apparatus having a calculation control device for calculating the shape of the object to be measured from data stored in a storage device. In a curved surface shape measuring apparatus for measuring the shape of a measurement object having a curved shape, the apparatus includes a base for setting the measurement object and a movable member movable in one direction along the measurement surface of the measurement object The moving member includes a light source that generates a single light beam as a measurement system, a polarizing beam splitter, a mirror, a quarter-wave plate, a corner cube, and light detection that detects the traveling direction of the light beam. and means, the measuring system optical path light source, a polarization beam splitter, a mirror, a quarter-wave plate, the object to be measured, the quarter-wave plate, a mirror, a polarization beam splitter, a corner cube, a polarizing beam splitter, mirror, 1 / 4 wavelength plate, measured object, 1/4 wavelength plate, mirror, light detecting means are arranged in this order, and the measured object differs through the corner cube detected by the light detecting means. Two places A curved surface shape measuring apparatus having a calculation control device for calculating the shape of the object to be measured from a signal obtained by shooting and data of a storage device for storing the position of the moving member. 4. The curved surface shape measuring apparatus according to claim 3, wherein a light beam that irradiates the object to be measured is incident on the object to be measured substantially perpendicularly. In a curved surface shape measuring apparatus for measuring the shape of a measurement object having a curved surface, the apparatus includes a base for setting the measurement object, an optical surface plate fixed to the base, and a measurement surface of the measurement object. along one direction, and it is composed of a rotary movable moving member, the light source to the moving member for generating a single light beam as a measurement system, a polarization beam splitter, 1/4-wave plate, a corner cube, half mirror And a light detection means , the optical path of the measurement system is a light source, a polarizing beam splitter, a half mirror, a 1/4 wavelength plate, an object to be measured, a 1/4 wavelength plate, a half mirror, a polarizing beam splitter, a corner cube, a polarizing beam The corner cube detected by the light detecting means is arranged in the order of splitter, half mirror, quarter wavelength plate, object to be measured, quarter wavelength plate, half mirror, light detecting means. A calculation control device for calculating the shape of the object to be measured from the signal obtained by irradiating two different places of the object to be measured via the data of the storage device for storing the position of the moving member. Characteristic curved surface shape measuring device. 6. The curved surface shape measuring apparatus according to claim 5, wherein a light beam that irradiates the object to be measured is incident on the object to be measured substantially perpendicularly. After guiding the light to the single-mode optical fiber from the light source, curved shape measuring apparatus according to claim 1-6, wherein the incident after the optical system of the measuring system. The light from the light source has a lens for focusing, through a pinhole mask arranged at the focal point of the lens, according to claim light beam, characterized in that entering the optical system subsequent said measuring system 1-6 The curved surface shape measuring apparatus described. Detection means for detecting the direction of travel of light beams, curved shape measuring device according to claim 1-8, wherein the the position sensor. Detection means for detecting the direction of travel of the light beam, the lens and the curved shape measuring apparatus according to claim 1-8, wherein the configuring in position sensor for detecting a light spot position arranged at the focal point of the lens. Curved shape measuring device according to claim 1-10, wherein a with roof mirror in place of the corner cube. The curved surface according to any one of claims 1 to 11 , wherein the shape of the object to be measured is obtained by integrating the data twice from a signal of the light detection means and data of a storage device storing the position of the moving member. Shape measuring device.

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