JP2009121927A - Eccentricity measuring device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an eccentricity measuring device and an eccentricity measuring method capable of suppressing the effect of light reflected on a surface other than a surface to be detected of a body to be inspected on measurement of eccentricity. <P>SOLUTION: The eccentricity measuring device 1 includes: an imaging optical system 7 having a prescribed focal length; a first mask 5 arranged at a position where light before incidence on the body S to be inspected is incident; a second mask 8 arranged at a position where the light after the reflection on the body S to be inspected is incident; and a condensing optical system 9 and a position sensor 10 for detecting the inclination of the light passing through the second mask 8 after the reflection on the body S to be inspected with respect to an optical axis Ax. Any of the first and second masks 5, 8 includes a pattern which comprises a shield part shielding light and a transmission part transmitting light and in which the position of the shield part and the position of the transmission part are inverted by rotating it about the optical axis by 180 degrees. The first and second masks 5, 8 are arranged so that the patterns are rotationally conjugate with each other by 180 degrees along the optical axis Ax. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an eccentricity measuring apparatus and an eccentricity measuring method.

Conventionally, a device having a focus lens system, an index, and a position sensor is known as an eccentricity measuring device (see, for example, Patent Document 1). In the eccentricity measuring apparatus described in Patent Document 1, an index image is projected onto the paraxial focal point of the test surface of the subject by the focus lens system, and the condensing position of the light reflected by the test surface is detected by the position sensor. The eccentric amount of the subject is measured based on the position information.
JP 2000-205998 A

  However, in the apparatus described in Patent Document 1, when the subject has a plurality of reflection surfaces, measurement is performed with the position sensor, including light reflected by a surface other than the surface to be examined of the subject.

  An object of the present invention is to provide an eccentricity measuring apparatus and an eccentricity measuring method capable of suppressing the influence of light reflected by a surface other than the test surface of a subject on the measurement of the eccentricity. .

  According to an embodiment illustrating the present invention, an apparatus for measuring the amount of eccentricity of a subject, which has a predetermined focal length and is disposed at a position where light before entering the subject passes. It comprises an optical system, a shielding part that shields light, and a passing part that allows light to pass through, and has a pattern in which the position of the shielding part and the position of the passing part are reversed by rotating 180 degrees around the optical axis. The mask arranged at the position where both the light before being incident on the subject and the light after being reflected by the subject enter, and the inclination of the light that has passed through the mask after being reflected by the subject with respect to the optical axis of the apparatus. There is provided an eccentricity measuring device comprising an inclination detecting means for detecting.

  According to an embodiment illustrating the present invention, an apparatus for measuring the amount of eccentricity of a subject, which has a predetermined focal length and is disposed at a position where light before entering the subject passes. It comprises an optical system, a shielding part that shields light, and a passing part that allows light to pass through, and has a pattern in which the position of the shielding part and the position of the passing part are reversed by rotating 180 degrees around the optical axis. It consists of a first mask arranged at a position where light before entering the subject enters, a shielding part that shields light, and a passage part that allows light to pass through, and is rotated 180 degrees around the optical axis. The position of the shielding portion and the position of the passage portion are reversed, and the second mask is disposed at a position where the light after being reflected by the subject is incident, and is reflected by the subject with respect to the optical axis of the apparatus. To detect the tilt of the light that has passed through the second mask after Comprising a detection means, the first and second masks, eccentricity measuring apparatus characterized by being arranged such that 180 degree rotation coupled along the optical axis pattern together is provided.

  According to an aspect of the present invention, a method for measuring the amount of eccentricity of a subject, which includes a shielding part that shields light and a passing part that allows light to pass through, is rotated 180 degrees around the optical axis. The light having passed through both the mask having a pattern in which the position of the shielding portion and the position of the passage portion are reversed and the imaging optical system having a predetermined focal length are incident on the subject, and reflected by the subject. There is provided an eccentricity measuring method comprising: passing the masked light through the mask; and detecting an inclination of the light that has passed through the mask after being reflected by the subject with respect to the optical axis of the apparatus. .

  According to an aspect of the present invention, a method for measuring the amount of eccentricity of a subject, which includes a shielding part that shields light and a passing part that allows light to pass through, is rotated 180 degrees around the optical axis. A step of causing light that has passed through both the first mask having a pattern in which the position of the shielding portion and the position of the passage portion are reversed and the imaging optical system having a predetermined focal length to enter the subject; The light reflected by the specimen consists of a shielding part that shields the light and a passing part that allows the light to pass through, and a pattern in which the position of the shielding part and the position of the passing part are reversed by rotating 180 degrees around the optical axis. And a step of detecting an inclination of light that has passed through the second mask after being reflected by the subject with respect to the optical axis of the apparatus, and the first and second masks include: , The pattern is 180 degree rotation conjugate with each other along the optical axis Eccentricity measuring method characterized by being arranged such that there is provided.

  According to the present invention, it is possible to provide an eccentricity measuring apparatus and an eccentricity measuring method capable of suppressing the influence of light reflected by a surface other than the test surface of the subject on the measurement of the eccentricity. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.
(First embodiment)

  With reference to FIG. 1, the structure of the eccentricity measuring apparatus 1 which concerns on 1st Embodiment is demonstrated. FIG. 1 is a configuration diagram of an eccentricity measuring apparatus according to the first embodiment.

  An eccentricity measuring apparatus 1 shown in FIG. 1 includes a light source 2, a beam expander 3, a diaphragm 4, a first mask 5, a beam splitter (light reflection / transmission member) 6, an imaging optical system 7, A second mask 8, a condensing optical system (condensing means) 9, and a position sensor (position observation means) 10 are provided. The eccentricity measuring apparatus 1 causes the light L output from the light source 2 to enter the subject S via the first mask 5 and the imaging optical system 7 and is reflected by the subject surface Sm of the subject S. This is an apparatus for measuring the amount of eccentricity of the subject S by making the light L enter the position sensor 10 via the imaging optical system 7 and the second mask 8.

  The light source 2 is a laser device, for example, and makes the light L enter the beam expander 3. The beam expander 3 collimates into a parallel light beam after expanding the light beam diameter of the light L output from the light source 2. The beam expander 3 causes the light L collimated to the parallel light flux to enter the first mask 5. Although the beam expander 3 is represented by two lenses in FIG. 1, it may be constituted by three or more lenses.

  A diaphragm 4 is disposed in the beam expander 3. The image of the diaphragm 4 is projected onto the curvature center C of the test surface Sm of the subject S by the imaging optical system 7 described later.

  The first mask 5 is disposed at a position where the light L before entering the subject S enters, more specifically, between the beam expander 3 and the beam splitter 6. The first mask 5 is disposed in the light source side optical system of the eccentricity measuring apparatus 1.

  The first mask 5 having a circular shape has a pattern including three shielding portions 5a that shield light and three passage portions 5b that allow light to pass therethrough. The shielding parts 5a and the passing parts 5b are alternately arranged in the circumferential direction. Each of the shielding part 5a and the passage part 5b has a fan shape with a central angle of 60 degrees extending radially from the center of the circle. In the pattern of the first mask 5, the position of the shielding part 5a and the position of the passage part 5b are reversed by rotating 180 degrees around the optical axis Ax. That is, when the first mask 5 is rotated 180 degrees around the optical axis Ax, the lightness and darkness of the pattern is reversed. In addition, in FIG. 1, the shielding part 5a is hatched for easy viewing.

  The beam splitter 6 transmits the light L that has passed through the passage portion 5 a of the first mask 5 and enters the imaging optical system 7. The beam splitter 6 also reflects the light L that has passed through the imaging optical system 7 after being reflected by the subject S and makes it incident on the second mask 8. That is, the beam splitter 6 separates the light incident on the subject S and the light reflected on the subject S by transmitting the light incident on the subject S and reflecting the light reflected by the subject S. . Thus, the beam splitter 6 serves as a beam splitting unit that separates the light incident on the subject S and the light reflected by the subject S, and guides the light reflected by the subject S to the condensing optical system 9. It also functions as a guide member.

  The imaging optical system 7 is a focusing optical system having a predetermined focal length. The imaging optical system 7 is also a variable focal length optical system that can change the focal length. The imaging optical system 7 is a position through which the light L before entering the subject S passes, and along the optical axis Ax of the eccentricity measuring apparatus 1 from the center of curvature C of the subject surface Sm of the subject S. Therefore, they are arranged at positions separated by the focal length. Although the imaging optical system 7 is represented by two lenses in FIG. 1, it may be constituted by three or more lenses or may be constituted by one lens.

  The second mask 8 is disposed at a position where the light L after being reflected by the subject S enters, more specifically, between the beam splitter 6 and the condensing optical system 9. The light L reflected by the subject S enters the second mask 8 after being reflected by the beam splitter 6. The second mask 8 is disposed in the detection system of the eccentricity measuring device 1.

  The second mask 8 having a circular shape has a pattern including three shielding portions 8a that shield light and three passage portions 8b that allow light to pass therethrough. The shielding part 8a and the passage part 8b are alternately arranged in the circumferential direction. Each of the shielding portion 8a and the passage portion 8b has a fan shape with a central angle of 60 degrees extending radially from the center of the circle. In the pattern of the second mask 8, the position of the shielding part 8a and the position of the passage part 8b are reversed by rotating 180 degrees around the optical axis Ax. That is, when the second mask 8 is rotated 180 degrees around the optical axis Ax, the lightness and darkness of the pattern is reversed. In FIG. 1, the shielding portion 8 a is hatched for easy viewing.

  The first and second masks 5 and 8 are arranged in the eccentricity measuring apparatus 1 so that the patterns are 180-degree rotationally conjugate with each other along the optical axis Ax. That is, in the eccentricity measuring apparatus 1, the patterns of the first mask 5 and the second mask 8 are 180 ° rotationally conjugate with each other with respect to the beam splitter 6, the imaging optical system 7, and the test surface Sm. Are arranged as follows.

  The condensing optical system 9 condenses the reflected light L from the subject S that has passed through the second mask 8 on the position sensor 10. The condensing optical system 9 is represented by one optical lens in FIG. 1, but may actually be constituted by a plurality of optical lenses.

  The position sensor 10 observes the position of the center of light quantity of the light L condensed by the condensing optical system 9. The position sensor 10 may be composed of, for example, a screen and a CCD camera. In this case, the CCD camera images spot light collected on the screen. Alternatively, the position sensor 10 may be, for example, an optical position sensor (Position Sensitive Detector; PSD). Alternatively, the position sensor 10 is, for example, a screen, and the position of the spot light collected on the screen may be observed by surveying.

  The position sensor 10 further reflects the light L that has passed through the second mask 8 after being reflected by the subject S that has passed through the condensing optical system 9 with respect to the optical axis Ax, based on the position of the center of light quantity of the reflected light L that has been observed. Detect tilt. Thus, the condensing optical system 9 and the position sensor 10 function as tilt detection means.

  Next, a method for measuring the eccentricity of the subject S using the eccentricity measuring apparatus 1 will be described. First, the light L emitted from the light source 2 is converted into a parallel light flux through the beam splitter 3. The parallel light beam obtained by the beam splitter 3 passes through the first mask 5, the beam splitter 6, and the imaging optical system 7 and then enters the test surface Sm of the subject S. At this time, only the light incident on the passage portion 5 b of the first mask 5 out of the parallel light flux passes through the first mask 5 and the light incident on the shielding portion 5 a of the first mask 5 is the first mask 5. Can't pass through and is cut here. The imaging optical system 7 changes the focal length so that the image of the stop 4 is projected onto the center of curvature C of the test surface Sm of the subject S.

  The light L reflected by the test surface Sm passes through the imaging optical system 7 again, is reflected by the beam splitter 6, and enters the second mask 8. At this time, only the light incident on the passage 8b of the second mask 8 out of the light L reflected by the test surface Sm passes through the second mask 8 and enters the shielding portion 8a of the second mask 8. The light cannot pass through the second mask 8 and is cut here. The light L that has passed through the second mask 8 is condensed on the position sensor 10 via the condensing optical system 9. From the position of the spot on the position sensor 10, the inclination of the light that has passed through the second mask 8 after being reflected by the test surface Sm with respect to the optical axis Ax is detected. Thereby, the amount of eccentricity of the test surface Sm of the subject S can be detected.

  When the subject S is composed of a plurality of optical systems, for example, as shown in FIG. 2, one surface Sx of the plurality of optical systems of the subject S is close to the center of curvature C of the subject surface Sm. When in position, the light reflected by the surface Sx also returns to the eccentricity measuring device 1. The light reflected by the surface Sx becomes noise that hinders high-accuracy measurement when the eccentricity is measured by detecting the reflected light from the test surface Sm. That is, the light reflected by the surface Sx may reduce the measurement accuracy of the eccentric amount of the subject S as noise light.

  Here, as understood from FIG. 2, the traveling direction of the light reflected by the test surface Sm is along the traveling direction of the light incident on the test surface Sm. On the other hand, the light reflected by the surface Sx located near the center of curvature C of the test surface Sm is inverted in a direction symmetrical to the incident light with respect to the optical axis Ax within the plane including the incident light and the optical axis Ax. And proceed. That is, as apparent from FIG. 2, the traveling direction of the light reflected by the surface Sm and the light reflected by the surface Sx is reversed with respect to the optical axis Ax.

  On the other hand, in the eccentricity measuring apparatus 1, the first and second masks 5 and 8 are arranged in the eccentricity measuring apparatus 1 so that the patterns are rotationally conjugate with each other by 180 degrees along the optical axis Ax. ing. Therefore, when the light that has passed through the passage portion 5b of the first mask 5 is reflected by the test surface Sm, the light reaches the passage portion 8b of the second mask 8 and can pass through the second mask 8, When light that has passed through the passage portion 5b of the first mask 5 is reflected by the surface Sx, the light reaches the shielding portion 8a of the second mask 8. As shown in FIG. 2, the light reflected by the test surface Sm is reflected in the same optical path direction as the incident light, whereas the surface Sx located near the center of curvature C of the test surface Sm. The reflected light is reflected in the direction of the optical path symmetric with respect to the optical axis Ax from the optical path of the incident light.

  As a result, in the eccentricity measuring apparatus 1, only the measurement light reflected by the test surface Sm passes through the passage portion 8 b of the second mask 8 and reaches the position sensor 10. Then, the measurement light reflected by the test surface Sm cannot be distinguished from the noise light reflected by the surface Sx, and the noise light reflected by the surface Sx is suppressed from affecting the measurement.

The imaging optical system 7 is a variable focal length optical system that can change the focal length. Therefore, even if the subject S is replaced and the position of the center of curvature of the subject surface Sm changes, the focal length of the imaging optical system 7 can be changed to change the position of the condensing point. As a result, the eccentricity measuring apparatus 1 can accurately measure the eccentricity amounts of subjects having various shapes.
(Second Embodiment)

  With reference to FIG. 3, the structure of the eccentricity measuring apparatus 11 which concerns on 2nd Embodiment is demonstrated. The eccentricity measuring apparatus 11 is different from the eccentricity measuring apparatus 1 according to the first embodiment in that it includes only one mask 5 instead of the two masks of the first and second masks 5 and 8. FIG. 3 is a configuration diagram of the eccentricity measuring apparatus according to the second embodiment.

  3 includes a light source 2, a beam expander 3, a diaphragm 4, a beam splitter (light reflection / transmission member) 6, a mask 5, an imaging optical system 7, and a condensing optical system. A system (light collecting means) 9 and a position sensor (position observation means) 10 are provided. The eccentricity measuring device 11 causes the light L output from the light source 2 to enter the subject S via the mask 5 and the imaging optical system 7, and the light L reflected by the subject surface Sm of the subject S. This is an apparatus for measuring the eccentricity of the subject S by making it incident on the position sensor 10 through the mask 5 and the imaging optical system 7 again.

  The beam splitter 6 transmits the light L that has passed through the beam expander 3 and makes it incident on the mask 5. The beam splitter 6 also reflects the light L that has passed through the imaging optical system 7 and the mask 5 after being reflected by the subject S, and enters the condensing optical system 9. That is, the beam splitter 6 separates the light incident on the subject S and the light reflected on the subject S by transmitting the light incident on the subject S and reflecting the light reflected by the subject S. . Thus, the beam splitter 6 serves as a beam splitting unit that separates the light incident on the subject S and the light reflected by the subject S, and guides the light reflected by the subject S to the condensing optical system 9. It also functions as a guide member.

  The mask 5 is disposed at a position where both the light L before being incident on the subject S and the light L after being reflected by the subject S are incident, more specifically, between the beam splitter 6 and the imaging optical system 7. ing.

  The mask 5 having a circular shape has a pattern including three shielding portions 5a that shield light and three passage portions 5b that allow light to pass through. The shielding parts 5a and the passing parts 5b are alternately arranged in the circumferential direction. Each of the shielding part 5a and the passage part 5b has a fan shape with a central angle of 60 degrees extending radially from the center of the circle. In the pattern of the first mask 5, the position of the shielding part 5a and the position of the passage part 5b are reversed by rotating 180 degrees around the optical axis Ax. That is, when the first mask 5 is rotated 180 degrees around the optical axis Ax, the lightness and darkness of the pattern is reversed. In FIG. 3, the shielding portion 5 a is hatched for easy viewing.

  The imaging optical system 7 is a focusing optical system having a predetermined focal length. The imaging optical system 7 is a position through which the light L before entering the subject S passes, and along the optical axis Ax of the eccentricity measuring apparatus 1 from the center of curvature C of the subject surface Sm of the subject S. Therefore, they are arranged at positions separated by the focal length. Although the imaging optical system 7 is represented by two lenses in FIG. 3, it may be constituted by three or more lenses or may be constituted by one lens.

  The condensing optical system 9 is disposed at a position where light L reflected by the subject S and then reflected by the beam splitter 6 enters. The condensing optical system 9 condenses the reflected light L from the subject S that has passed through the mask 5 on the position sensor 10. The condensing optical system 9 is represented by one optical lens in FIG. 3, but may actually be constituted by a plurality of optical lenses.

  The position sensor 10 observes the position of the center of light quantity of the light L condensed by the condensing optical system 9. The position sensor 10 detects the inclination of the light L that has passed through the mask 5 after being reflected by the subject S that has passed through the condensing optical system 9 with respect to the optical axis Ax, based on the position of the center of light quantity of the reflected light L that has been observed. . Thus, the condensing optical system 9 and the position sensor 10 function as tilt detection means.

  Next, a method for measuring the eccentricity of the subject S by the eccentricity measuring device 11 will be described. First, the light L emitted from the light source 2 is converted into a parallel light flux through the beam splitter 3. The parallel light beam obtained by the beam splitter 3 passes through the beam splitter 6, the mask 5, and the imaging optical system 7 and then enters the test surface Sm of the subject S. At this time, of the parallel light flux, only the light incident on the passage portion 5b of the mask 5 passes through the mask 5, and the light incident on the shielding portion 5a of the mask 5 cannot pass through the mask 5 and is cut here. . The imaging optical system 7 changes the focal length so that the image of the stop 4 is projected onto the center of curvature C of the test surface Sm of the subject S.

  The light L reflected by the test surface Sm passes through the imaging optical system 7 and the mask 5 again, is reflected by the beam splitter 6 and enters the condensing optical system 9. At this time, among the light L reflected by the test surface Sm, only the light incident on the passage portion 5b of the mask 5 passes through the mask 5, and the light incident on the shielding portion 5a of the mask 5 passes through the mask 5. It can't be cut here. The light L incident on the condensing optical system 9 is condensed on the position sensor 10. From the position of the spot on the position sensor 10, the inclination of the light that has passed through the mask 5 after being reflected by the test surface Sm with respect to the optical axis Ax is detected. Thereby, the amount of eccentricity of the test surface Sm of the subject S can be detected.

  In the case where the subject S is composed of a plurality of optical systems, when one surface of the plurality of optical systems of the subject S is at a position close to the center of curvature C of the subject surface Sm, the center of curvature C The light reflected by the surface near the position also returns to the eccentricity measuring device 11. The light reflected by the surface close to the center of curvature C becomes noise that hinders high-accuracy measurement when the eccentricity is measured by detecting the reflected light from the surface Sm to be measured. That is, the light reflected by the surface close to the center of curvature C may reduce the measurement accuracy of the eccentricity amount of the subject S as noise light.

  Here, as discussed based on FIG. 2, the traveling direction of the light reflected by the test surface Sm is along the traveling direction of the light incident on the test surface Sm. On the other hand, the light reflected by the surface near the center of curvature C of the test surface Sm is inverted in a direction symmetrical to the incident light with respect to the optical axis Ax within the plane including the incident light and the optical axis Ax. proceed. That is, the traveling direction of the light reflected by the test surface Sm and the light reflected by the surface near the center of curvature C are reversed with respect to the optical axis Ax.

  On the other hand, in the eccentricity measuring apparatus 11, the mask 5 having a pattern in which the shielding part 5 a and the passing part 5 b are reversed by being rotated 180 degrees about the optical axis Ax is included in the eccentricity measuring apparatus 11. The light L before being incident on S and the light L after being reflected by the subject S are arranged at positions where they are incident. Therefore, when the light L that has passed through the passage portion 5b of the mask 5 before being incident on the subject S is reflected by the subject surface Sm, it can reach the passage portion 5b of the mask 5 again and pass through the mask 5, When the light that has passed through the passage portion 5b of the mask 5 is reflected by a surface that is close to the center of curvature C, it reaches the shielding portion 5a of the mask 5. This is because the light reflected by the test surface Sm is reflected in the same optical path direction as the incident light, whereas the light reflected by the surface close to the center of curvature C of the test surface Sm is the optical path of the incident light. Is reflected in the optical path direction symmetric with respect to the optical axis Ax.

As a result, in the eccentricity measuring apparatus 11, only the measurement light reflected by the test surface Sm passes through the passage portion 5 b of the mask 5 and reaches the position sensor 10. Then, the measurement light reflected by the test surface Sm and the noise light reflected by the surface near the center of curvature C cannot be distinguished, and the noise light reflected by the surface near the center of curvature C is indistinguishable. Affects the measurement.
(Third embodiment)

  With reference to FIG. 4, the structure of the eccentricity measuring apparatus 20 which concerns on 3rd Embodiment is demonstrated. The eccentricity measuring apparatus 20 according to the third embodiment displays an image of the aperture by the imaging optical system in that the position where the image of the aperture is projected by the imaging optical system is a paraxial focus of the test surface of the subject. This is different from the eccentricity measuring apparatus 1 according to the first embodiment in which the projection position is the center of curvature of the test surface of the subject. FIG. 4 is a configuration diagram of the eccentricity measuring apparatus according to the third embodiment.

  4 includes a light source 2, a beam expander 3, a diaphragm 4, an imaging optical system 7, a first mask 5, a beam splitter (light reflection / transmission member) 6, A second mask 8, a condensing optical system (condensing means) 9, and a position sensor (position observation means) 10 are provided. The eccentricity measuring device 20 causes the light L output from the light source 2 to enter the subject S via the imaging optical system 7 and the first mask 5 and is reflected by the subject surface Sm of the subject S. In this apparatus, the amount of eccentricity of the subject S is measured by causing the light L to enter the position sensor 10 via the second mask 8.

  The light source 2 makes light L incident on the beam expander 3. The beam expander 3 collimates into a parallel light beam after expanding the light beam diameter of the light L output from the light source 2. The beam expander 3 causes the light L collimated to a parallel light beam to enter the imaging optical system 7. The beam expander 3 is represented by two lenses in FIG. 4, but may be composed of three or more lenses.

  A diaphragm 4 is disposed in the beam expander 3. The image of the diaphragm 4 is projected onto the paraxial focus F of the test surface Sm of the subject S by the imaging optical system 7 described later.

  The imaging optical system 7 is a focusing optical system having a predetermined focal length. The imaging optical system 7 forms an image of the diaphragm 4 at a paraxial focal point F of the test surface Sm of the subject S together with the subject S at which the light L before entering the subject S passes. It is arranged at the position to image. Although the imaging optical system 7 is represented by two lenses in FIG. 4, it may be constituted by three or more lenses or may be constituted by one lens.

  The first mask 5 is disposed at a position where the light L before entering the subject S enters, more specifically, between the imaging optical system 7 and the beam splitter 6. The first mask 5 is disposed in the light source side optical system of the eccentricity measuring device 20.

  The first mask 5 having a circular shape has a pattern including three shielding portions 5a that shield light and three passage portions 5b that allow light to pass therethrough. In FIG. 4, the shielding portion 5a is hatched for easy viewing.

  The beam splitter 6 transmits the light L that has passed through the passage portion 5 a of the first mask 5 and makes it incident on the subject S. The beam splitter 6 also reflects the light L reflected by the subject S and makes it incident on the second mask 8. That is, the beam splitter 6 separates the light incident on the subject S and the light reflected on the subject S by transmitting the light incident on the subject S and reflecting the light reflected by the subject S. . Thus, the beam splitter 6 serves as a beam splitting unit that separates the light incident on the subject S and the light reflected by the subject S, and guides the light reflected by the subject S to the condensing optical system 9. It also functions as a guide member.

  The second mask 8 is disposed at a position where the light L after being reflected by the subject S enters, more specifically, between the beam splitter 6 and the condensing optical system 9. The light L reflected by the subject S enters the second mask 8 after being reflected by the beam splitter 6. The second mask 8 is disposed in the detection system of the eccentricity measuring device 20.

  The second mask 8 having a circular shape has a pattern including three shielding portions 8a that shield light and three passage portions 8b that allow light to pass therethrough. In FIG. 4, the shielding portion 8a is hatched for easy viewing.

  The first and second masks 5 and 8 are arranged in the eccentricity measuring apparatus 20 so that the patterns are 180-degree rotationally conjugate with each other along the optical axis Ax. That is, in the eccentricity measuring apparatus 20, the first mask 5 and the second mask 8 are arranged so that the patterns are 180-degree rotationally conjugate with each other with respect to the beam splitter 6 and the test surface Sm.

  The condensing optical system 9 condenses the reflected light L from the subject S that has passed through the second mask 8 on the position sensor 10. Although the condensing optical system 9 is represented by one optical lens in FIG. 4, it may actually be constituted by a plurality of optical lenses.

  The position sensor 10 observes the position of the center of light quantity of the light L condensed by the condensing optical system 9. The position sensor 10 further reflects the light L that has passed through the second mask 8 after being reflected by the subject S that has passed through the condensing optical system 9 with respect to the optical axis Ax, based on the position of the center of light quantity of the reflected light L that has been observed. Detect tilt. Thus, the condensing optical system 9 and the position sensor 10 function as tilt detection means.

  Next, a method for measuring the eccentricity of the subject S using the eccentricity measuring apparatus 20 will be described. First, the light L emitted from the light source 2 is converted into a parallel light flux through the beam splitter 3. The parallel light beam obtained by the beam splitter 3 passes through the imaging optical system 7, the first mask 5, and the beam splitter 6 and then enters the test surface Sm of the subject S. At this time, only the light incident on the passage portion 5 b of the first mask 5 out of the parallel light flux passes through the first mask 5 and the light incident on the shielding portion 5 a of the first mask 5 is the first mask 5. Can't pass through and is cut here. The imaging optical system 7 changes the focal length of the subject S so that the image of the stop 4 is projected onto the paraxial center F of the subject surface Sm of the subject S together with the subject S.

  The light L reflected by the test surface Sm returns to the beam splitter 6 and is reflected there and enters the second mask 8. At this time, only the light incident on the passage 8b of the second mask 8 out of the light L reflected by the test surface Sm passes through the second mask 8 and enters the shielding portion 8a of the second mask 8. The light cannot pass through the second mask 8 and is cut here. The light L that has passed through the second mask 8 is condensed on the position sensor 10 via the condensing optical system 9. From the position of the spot on the position sensor 10, the inclination of the light that has passed through the second mask 8 after being reflected by the test surface Sm with respect to the optical axis Ax is detected. Thereby, the amount of eccentricity of the test surface Sm of the subject S can be detected.

  When the subject S is composed of a plurality of optical systems, for example, as shown in FIG. 5, one surface Sx of the plurality of optical systems of the subject S is a paraxial focal point F of the subject surface Sm. When it is in a close position, the light reflected by the surface Sx also returns into the eccentricity measuring device 20. The light reflected by the surface Sx becomes noise that hinders high-accuracy measurement when the eccentricity is measured by detecting the reflected light from the test surface Sm. That is, the light reflected by the surface Sx may reduce the measurement accuracy of the eccentric amount of the subject S as noise light.

  Here, as understood from FIG. 5, the traveling direction of the light reflected by the test surface Sm and the traveling direction of the light incident on the test surface Sm are not reversed with respect to the optical axis Ax. It remains in the same direction with respect to the optical axis Ax. On the other hand, the light reflected by the surface Sx located near the paraxial focal point F of the test surface Sm is inverted in a direction symmetrical to the incident light with respect to the optical axis Ax within the plane including the incident light and the optical axis Ax. Then proceed. That is, as is clear from FIG. 5, the traveling direction of the light reflected by the test surface Sm and the light reflected by the surface Sx are substantially reversed with respect to the optical axis Ax.

  On the other hand, in the eccentricity measuring apparatus 20, the first and second masks 5 and 8 are arranged in the eccentricity measuring apparatus 20 so that the patterns are rotationally conjugate with each other by 180 degrees along the optical axis Ax. ing. Therefore, when the light that has passed through the passage portion 5b of the first mask 5 is reflected by the surface to be measured Sm, the traveling direction reaches the passage portion 8b of the second mask 8 without reversing the traveling direction with respect to the optical axis Ax. Although the light can pass through the second mask 8, the traveling direction is reversed with respect to the optical axis Ax when the light that has passed through the passage portion 5b of the first mask 5 is reflected by the surface Sx. It will reach the shielding part 8a.

  As a result, in the eccentricity measuring apparatus 20, only the measurement light reflected by the test surface Sm passes through the passage portion 8 b of the second mask 8 and reaches the position sensor 10. Then, the measurement light reflected by the test surface Sm cannot be distinguished from the noise light reflected by the surface Sx, and the noise light reflected by the surface Sx is suppressed from affecting the measurement.

The imaging optical system 7 is a variable focal length optical system that can change the focal length. Therefore, even if the subject S is replaced and the position of the paraxial focus of the test surface Sm changes, the focal length of the imaging optical system 7 can be changed to change the position of the focal point. As a result, the eccentricity measuring apparatus 20 can accurately measure the eccentricity amounts of subjects having various shapes.
(Fourth embodiment)

  With reference to FIG. 6, the structure of the eccentricity measuring apparatus 21 which concerns on 4th Embodiment is demonstrated. The eccentricity measuring device 21 is different from the eccentricity measuring device 20 according to the third embodiment in that it includes only one mask 5 instead of the two masks of the first and second masks 5 and 8. FIG. 6 is a configuration diagram of the eccentricity measuring apparatus according to the fourth embodiment.

  6 includes a light source 2, a beam expander 3, a diaphragm 4, an imaging optical system 7, a beam splitter (light reflection / transmission member) 6, a mask 5, and condensing optics. A system (light collecting means) 9 and a position sensor (position observation means) 10 are provided. The eccentricity measuring device 21 causes the light L output from the light source 2 to enter the subject S via the mask 5 and the imaging optical system 7, and the light L reflected by the subject surface Sm of the subject S. This is a device that measures the eccentricity of the subject S by being incident on the position sensor 10 only through the mask 5 this time.

  The beam splitter 6 transmits the light L that has passed through the imaging optical system 7 and enters the mask 5. The beam splitter 6 also reflects the light L that has passed through the mask 5 after being reflected by the subject S and makes it incident on the condensing optical system 9. That is, the beam splitter 6 separates the light incident on the subject S and the light reflected on the subject S by transmitting the light incident on the subject S and reflecting the light reflected by the subject S. . Thus, the beam splitter 6 serves as a beam splitting unit that separates the light incident on the subject S and the light reflected by the subject S, and guides the light reflected by the subject S to the condensing optical system 9. It also functions as a guide member.

  The mask 5 is disposed at a position where both the light L before being incident on the subject S and the light L after being reflected by the subject S are incident, more specifically, between the beam splitter 6 and the subject S. .

  The mask 5 having a circular shape has a pattern including three shielding portions 5a that shield light and three passage portions 5b that allow light to pass through. In FIG. 6, the shielding part 5a is hatched for easy viewing.

  The condensing optical system 9 is disposed at a position where light L reflected by the subject S and then reflected by the beam splitter 6 enters. The condensing optical system 9 condenses the reflected light L from the subject S that has passed through the mask 5 on the position sensor 10. Although the condensing optical system 9 is represented by one optical lens in FIG. 6, it may actually be constituted by a plurality of optical lenses.

  The position sensor 10 observes the position of the center of light quantity of the light L condensed by the condensing optical system 9. The position sensor 10 is light that has passed through the mask 5 after being reflected by the subject S with respect to the optical axis Ax, based on the position of the center of gravity of the reflected light L that has been observed, and that has passed through the condensing optical system 9. Detect the slope of. Thus, the condensing optical system 9 and the position sensor 10 function as tilt detection means.

  Next, a method for measuring the eccentricity of the subject S by the eccentricity measuring device 21 will be described. First, the light L emitted from the light source 2 is converted into a parallel light flux through the beam splitter 3. The parallel light beam obtained by the beam splitter 3 passes through the imaging optical system 7, the beam splitter 6, and the mask 5 and then enters the test surface Sm of the subject S. At this time, of the parallel light flux, only the light incident on the passage portion 5b of the mask 5 passes through the mask 5, and the light incident on the shielding portion 5a of the mask 5 cannot pass through the mask 5 and is cut here. . The imaging optical system 7 changes the focal length of the subject S so that the image of the stop 4 is projected onto the paraxial focus F of the subject surface Sm of the subject S together with the subject S.

  The light L reflected by the test surface Sm passes through the mask 5, is reflected by the beam splitter 6, and enters the condensing optical system 9. At this time, among the light L reflected by the test surface Sm, only the light incident on the passage portion 5b of the mask 5 passes through the mask 5, and the light incident on the shielding portion 5a of the mask 5 passes through the mask 5. It can't be cut here. The light L incident on the condensing optical system 9 is condensed on the position sensor 10. From the position of the spot on the position sensor 10, the inclination of the light that has passed through the mask 5 after being reflected by the test surface Sm with respect to the optical axis Ax is detected. Thereby, the amount of eccentricity of the test surface Sm of the subject S can be detected.

  In the case where the subject S is composed of a plurality of optical systems, when one surface of the plurality of optical systems of the subject S is at a position close to the paraxial focus F of the subject surface Sm, the paraxial The light reflected by the surface close to the focal point F also returns to the eccentricity measuring device 21. The light reflected by the surface close to the paraxial focal point F becomes noise that hinders high-accuracy measurement when the eccentricity is measured by detecting the reflected light from the surface Sm to be measured. . That is, the light reflected by the surface close to the paraxial focus F may reduce the measurement accuracy of the eccentricity amount of the subject S as noise light.

  Here, as discussed based on FIG. 5, the traveling direction of the light reflected by the test surface Sm and the traveling direction of the light incident on the test surface Sm are not in an inverted relationship with respect to the optical axis Ax. , The same direction with respect to the optical axis Ax remains. On the other hand, the light reflected by the surface close to the paraxial focal point F of the test surface Sm is inverted in a direction symmetrical to the incident light with respect to the optical axis Ax within the plane including the incident light and the optical axis Ax. And proceed. That is, the traveling direction of the light reflected by the test surface Sm and the light reflected by the surface near the paraxial focal point F are substantially reversed with respect to the optical axis Ax.

  On the other hand, in the eccentricity measuring device 21, the mask 5 having a pattern in which the shielding portion 5 a and the passage portion 5 b are reversed by rotating 180 degrees around the optical axis Ax is the subject in the eccentricity measuring device 21. The light L before being incident on S and the light L after being reflected by the subject S are arranged at positions where they are incident. Therefore, when the light L that has passed through the passage portion 5b of the mask 5 before being incident on the subject S is reflected by the subject surface Sm, it can reach the passage portion 5b of the mask 5 again and pass through the mask 5, When light that has passed through the passage portion 5b of the mask 5 is reflected by a surface that is close to the paraxial focal point F, the light reaches the shielding portion 5a of the mask 5.

  As a result, in the eccentricity measuring device 21, only the measurement light reflected by the test surface Sm passes through the passage portion 5 b of the mask 5 and reaches the position sensor 10. The measurement light reflected by the test surface Sm and the noise light reflected by the surface close to the paraxial focus F cannot be distinguished, and are reflected by the surface close to the paraxial focus F. The noise light is prevented from affecting the measurement.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, the first and second masks 5 and 8 and the mask 5 have three shielding portions 5a and 8a and three passage portions 5b and 8b as shown in FIGS. It is not restricted to the pattern arrange | positioned in. The first and second masks 5 and 8 and the mask 5 may be patterns that can be reversed by rotating the mask 180 degrees.

  Specifically, for example, as shown in FIG. 7 and FIG. 8, an odd number of shielding portions and the same number of passage portions and fan shapes having the same central angle are alternately arranged and arranged alternately. It may be a pattern. That is, as shown in FIG. 7, the first mask 5 (mask 5) and the second mask 8 each have a pattern formed by one shielding portion 5a, 8a and one passage portion 5b, 8b. May be presented. In this case, the shielding portions 5a and 8a and the passing portions 5b and 8b all have a semicircular shape. Alternatively, as shown in FIG. 8, the first mask 5 (mask 5) and the second mask 8 have patterns formed by five shielding portions 5a and 8a and five passage portions 5b and 8b, respectively. May be presented. In this case, the shielding portions 5a and 8a and the passing portions 5b and 8b all have a fan shape with a central angle of 36 degrees.

  The position sensor 10 can also detect the amount of light, and the position and amount of light center of gravity detected by the position sensor 10 are compared with the position and amount of light center of light detected when the masks 5 and 8 are not inserted. Thus, the amount of eccentricity of the test surface Sm may be calculated. In this case, since the masks 5 and 8 are not inserted, the position sensor 10 causes the light reflected by the test surface Sm and the light reflected by the surface Sx near the center of curvature (or paraxial focal point) of the test surface Sm. The center of gravity and the light amount of the total light amount are detected.

  In the above description, the position sensor 10 observes the position of the center of gravity of the light L collected by the condensing optical system 9. However, the present invention is not limited to this. For example, a position where the light amount of the collected light is maximum may be observed.

  The imaging optical system 7 may be an optical system that cannot change the focal length and has a fixed focal length.

It is a block diagram of the eccentricity measuring apparatus which concerns on 1st Embodiment. It is a figure which shows the optical path direction in which the light reflected by a subject advances. It is a block diagram of the eccentricity measuring apparatus which concerns on 2nd Embodiment. It is a block diagram of the eccentricity measuring apparatus which concerns on 3rd Embodiment. It is a figure which shows the optical path direction in which the light reflected by a subject advances. It is a block diagram of the eccentricity measuring apparatus which concerns on 4th Embodiment. It is a top view of the 1st and 2nd mask. It is a top view of the 1st and 2nd mask.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 11, 20, 21 ... Eccentricity measuring apparatus, 2 ... Light source, 3 ... Beam expander, 4 ... Aperture, 5 ... 1st mask, 6 ... Beam splitter, 7 ... Imaging optical system, 8 ... 2nd 9 ... Condensing optical system, 10 ... Position sensor.

Claims (10)

An apparatus for measuring the amount of eccentricity of a subject,
An imaging optical system having a predetermined focal length and disposed at a position where light before entering the subject passes;
It comprises a shielding part that shields light and a passing part that allows light to pass through, and has a pattern in which the position of the shielding part and the position of the passing part are reversed by rotating 180 degrees around the optical axis, and A mask disposed at a position where both the light before being incident on the subject and the light after being reflected by the subject are incident;
An eccentricity measuring device comprising: an inclination detecting unit that detects an inclination of light that has passed through the mask after being reflected by the subject with respect to an optical axis of the device. An apparatus for measuring the amount of eccentricity of a subject,
An imaging optical system having a predetermined focal length and disposed at a position where light before entering the subject passes;
It comprises a shielding part that shields light and a passing part that allows light to pass through, and has a pattern in which the position of the shielding part and the position of the passing part are reversed by rotating 180 degrees around the optical axis, and A first mask arranged at a position where light before entering the subject enters;
It comprises a shielding part that shields light and a passing part that allows light to pass through, and has a pattern in which the position of the shielding part and the position of the passing part are reversed by rotating 180 degrees around the optical axis, and A second mask disposed at a position where light after being reflected by the subject enters;
Inclination detecting means for detecting the inclination of light that has passed through the second mask after being reflected by the subject with respect to the optical axis of the apparatus,
The eccentric measuring apparatus, wherein the first and second masks are arranged such that the patterns are 180 ° rotationally conjugate with each other along the optical axis.   3. The eccentricity measuring apparatus according to claim 1, wherein the imaging optical system is arranged so that incident light is imaged at a paraxial focal point of a test surface of the subject.   3. The eccentricity measuring apparatus according to claim 1, wherein the imaging optical system is arranged so that incident light is imaged at a center of curvature of a test surface of the subject.   The guide member according to claim 1, further comprising: a guide member that separates light incident on the subject and light reflected by the subject and guides the light reflected by the subject to the tilt detection unit. The eccentricity measuring apparatus as described in any one of Claims.   6. The tilt detection unit according to claim 1, further comprising: a condensing unit; and a position observing unit that observes the center of light amount or the maximum light amount of the light collected by the condensing unit. The eccentricity measuring apparatus according to claim 1.   The decentering measurement apparatus according to claim 1, wherein the imaging optical system can change the focal length.   8. The imaging optical system according to claim 1, wherein the imaging optical system has a finite focal length, and is disposed at a position away from the center of curvature of the subject along the optical axis by the focal length. The eccentricity measuring apparatus as described in any one of Claims. A method for measuring the amount of eccentricity of a subject,
A mask comprising a shielding part for shielding light and a passing part for allowing light to pass, and having a pattern in which the position of the shielding part and the position of the passing part are reversed by rotating 180 degrees around the optical axis; and Allowing light that has passed through both of the imaging optical system having a predetermined focal length to enter the subject; and
Passing the mask through the light reflected by the subject;
And a step of detecting an inclination of light that has passed through the mask after being reflected by the subject with respect to the optical axis of the apparatus. A method for measuring the amount of eccentricity of a subject,
A first portion having a pattern in which the position of the shielding portion and the position of the passage portion are reversed by rotating 180 degrees around the optical axis. Making light incident on both the mask and the imaging optical system having a predetermined focal length incident on the subject;
The light reflected by the subject includes a shielding part that shields the light and a passing part that allows the light to pass through. The position of the shielding part and the position of the passing part are rotated by 180 degrees about the optical axis. Passing through a second mask having a pattern in which
Detecting an inclination of light that has passed through the second mask after being reflected by the subject with respect to the optical axis of the apparatus, and
The eccentric measurement method, wherein the first and second masks are arranged such that the patterns are 180 ° rotationally conjugate with each other along the optical axis.

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