JP2006112811A - Mirror frame and decentration measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decentration measuring method or the like capable of measuring a decentration amount always highly accurately, regardless of a shape error of the surface to be inspected. <P>SOLUTION: This method has a first reference object position measuring process for measuring positions of three balls 100d or the like provided on a lens frame 100c; an optical element shape measuring process for measuring the shape of a prescribed surface of a lens 100; a measuring coordinate system calculation process for calculating the position of a measuring coordinate system relative to the lens frame 100c; a coordinate conversion calculation process for performing coordinate conversion of a measurement result in the optical element shape measuring process into the measuring coordinate system; a support process for supporting the lens frame 100c by a fixing frame 140 (mounting part 160); a second reference object position measuring process for measuring the position of the ball 100d of the supported lens frame 100c; a first frame body decentration amount calculation process for calculating the decentration amount to a reference axis 160a of the lens frame 100c; and an optical element decentration amount calculation process for calculating the decentration amount of the lens 100 to the reference axis 160a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens frame that holds an optical element, and a method for measuring the amount of eccentricity of an optical element disposed at a predetermined position in the lens frame.

  Conventionally, a method of measuring the amount of eccentricity of an optical system arranged at a predetermined position in a lens frame is known. Here, the optical system to be measured is composed of a plurality of lenses (a plurality of test surfaces). As a typical eccentricity measuring method, a technique using an autocollimation method has been proposed. In the eccentricity measurement using the autocollimation method, light is irradiated to the center position of the paraxial curvature of each test surface to be measured. Then, the image position of the reflected light on each test surface is detected. Further, the eccentricity of each test surface with respect to a predetermined reference axis is calculated based on the image position.

Here, consider the case where the test surface is an aspherical surface. At this time, the eccentricity of the test surface needs to measure both the position of the paraxial curvature center and the inclination of the aspherical axis. Therefore, an eccentricity measuring method for measuring the eccentricity of the optical system (surface to be measured) when the optical system to be measured includes an aspherical surface has been proposed (for example, see Patent Document 1). In Patent Document 1, as shown in FIG. 13, the decentering of each test surface with respect to the reference axis 2 of the test lens system 1 composed of a spherical surface and an aspherical surface is measured using an autocollimation method. Here, the test surfaces are four lens surfaces S ₁ , S ₂ , S ₃ and S ₄ . The lens surfaces S ₁ and S ₃ are aspheric surfaces, and the lens surfaces S ₂ and S ₄ are spherical surfaces.

First, when the test surface is a spherical surface, for example, for the lens surface S ₂ , the image position of the center of curvature S ₂ ′ is detected by reflected light. Thereby, the amount of eccentricity of the lens surface S ₂ with respect to the reference axis 2 is obtained. When the test surface is aspheric, for example, for the lens surface S ₁ , the image position of the paraxial center of curvature S ₁ ′ is detected by reflected light. At the same time, detects the image position of the center of curvature of the aspherical portion a predetermined distance from the aspherical axis S ₁ "of the lens surface S _1. Then, the paraxial curvature center S ₁ 'position and the non-lens surface S ₁ The slope of the spherical axis S ₁ ″ is calculated. As a result, the eccentricity of the lens surface S ₁ with respect to the reference axis 2 is calculated. In this way, the tilt amounts ε ₁ , ε ₃ , shift amounts σ ₁ , σ ₂ , σ ₃ , σ _4, etc. with respect to the reference axis of each lens surface are obtained.

JP-A-9-325085

  As described above, in the prior art shown in FIG. 13, when the test surface is an aspherical surface, the position of the center of curvature of the aspherical portion separated by a predetermined distance from the aspherical surface is detected, and the inclination of the aspherical axis is detected. Seeking. Specifically, the position of the center of gravity of the image of the reflected light at a predetermined annular zone portion around the aspherical axis of the test surface is detected. Then, the aspheric axis is calculated based on the position of the center of gravity of the image. Here, there are cases where the measured aspherical ring-shaped portion has a shape error such as unevenness. If there is such a shape error, the image position of the reflected light changes. For this reason, the aspherical axis of the test surface cannot be obtained accurately. In addition, there may be a case where a shape error such as unevenness occurs in the paraxial region of the test surface. At this time, the image position of the paraxial curvature center changes. For this reason, the position of the paraxial curvature center of the test surface cannot be obtained accurately. Therefore, the conventional eccentricity measuring method has a problem that the amount of eccentricity cannot be obtained with high accuracy if there is a shape error on the surface to be measured.

  The present invention has been made in view of the above, and provides an eccentricity measuring method capable of always measuring the amount of eccentricity with high accuracy regardless of the shape error of the surface to be measured, and a lens frame used for the eccentricity measuring method. For the purpose.

  In order to solve the above-described problems and achieve the object, according to the first aspect of the present invention, the first frame body that holds the optical element and includes at least three reference objects, and the first frame body are supported. It is possible to provide a lens frame characterized by comprising the second frame body.

  According to a preferred aspect of the present invention, it is desirable that the reference object has a spherical or hemispherical shape. Furthermore, according to the preferable aspect of this invention, it is desirable for the 2nd frame to have an opening part in the position facing the reference | standard thing with which a 1st frame is equipped. In addition, according to a preferred aspect of the present invention, it is desirable that the second frame supports a plurality of first frames.

  According to a preferred aspect of the present invention, the cam frame further includes a cam pin formed on the outer peripheral portion of the first frame body, and a cam groove formed on the inner peripheral portion of the second frame body, It is desirable that the first frame is supported so as to be movable in the direction along the optical axis of the optical element with respect to the second frame. Furthermore, according to a preferable aspect of the present invention, it is desirable that the first frame is fixed to the second frame.

  According to the second aspect of the present invention, the first reference object position measuring step for measuring the positions of at least three reference objects provided in the first frame, and the predetermined optical element held by the first frame. An optical element shape measuring step for measuring the shape of the surface, a measurement coordinate system calculating step for calculating the position of the measurement coordinate system with respect to the first frame based on the measurement result of the first reference object position measuring step, and the optical element A coordinate conversion calculation step for converting the measurement result of the shape measurement step into a measurement coordinate system, a support step for supporting the first frame by the second frame, and a reference object for the first frame supported A second reference object position measuring step for measuring the position of the first frame, and a first frame eccentricity calculation for calculating an eccentric amount with respect to the reference axis of the first frame based on the measurement results of the second reference object position measuring step Optical element eccentricity meter that calculates the process and the amount of eccentricity of the optical element with respect to the reference axis That a step can be provided an eccentric measurement method comprising.

  According to a preferred aspect of the present invention, it is desirable that the reference axis is determined by the second frame body. Furthermore, according to a preferred aspect of the present invention, it is desirable that the reference object has a spherical or hemispherical shape. In addition, according to a preferred aspect of the present invention, it is desirable that the second reference object position measuring step measures the position of the reference object by rotating the second frame around a predetermined axis.

  According to a preferred aspect of the present invention, it is desirable to measure the center position of the reference object by bringing the probe into contact with the reference object in the first reference object position measuring step and the second reference object position measuring step. .

  Further, according to a preferred aspect of the present invention, in the second reference object position measurement step, it is desirable to measure the center position of the reference object by irradiating the reference object with measurement light using an interferometer.

  According to a preferred aspect of the present invention, the reference object is made of a magnetic material, and it is desirable to measure the position of the reference object with a magnetic sensor in the second reference object position measurement step.

  Further, according to the third aspect of the present invention, the first positional relationship measuring step for measuring the positional relationship between at least three reference objects and the optical element, and the second measuring method for measuring the positional relationship between the reference object and the frame. A positional relationship measurement step, and an eccentricity amount calculation step of calculating an eccentricity amount with respect to the frame of the optical element based on the measurement result of the first positional relationship measurement step and the measurement result of the second positional relationship measurement step. It is desirable.

  According to the first aspect of the present invention, the first frame body holds an optical element such as a lens. The first frame includes at least three reference objects. Furthermore, the first frame is supported by the second frame. An optical element and a reference object are measured by a three-dimensional shape measuring machine using a probe or the like. Thereby, the relative positional relationship between the optical element and the reference object can be calculated. In addition, in a state where the first frame is supported by the second frame, the reference object is measured by, for example, a three-dimensional shape measuring machine. Thereby, the relative positional relationship between the second frame and the first frame can be calculated. The relative positional relationship between the second frame and the optical element can also be calculated. As a result, according to the present invention, the amount of eccentricity can always be measured with high accuracy regardless of the shape error of the optical element that is the test surface.

  Further, according to the second aspect of the present invention, at least three reference objects and the surface shape of the optical element are obtained by the first reference object position measuring step and the optical element shape measuring step, for example, by a three-dimensional shape measuring machine. Measure each. The measurement coordinate system determined by the reference object can be calculated by the measurement coordinate system calculation step. In addition, the relative positional relationship of the optical element with respect to the measurement coordinate system can be obtained by the coordinate conversion calculation process. Further, in the second reference object position measuring step, the position of the reference object of the first frame body that is supported by the second frame body is measured by, for example, a three-dimensional shape measuring machine. In the first frame eccentricity calculation step, the relative positional relationship of the first frame relative to the reference axis can be calculated. Finally, the amount of eccentricity of the optical element with respect to the reference axis is obtained by the optical element eccentricity calculating step. Thereby, the relative positional relationship between the second frame and the optical element can be known. As a result, according to the present invention, there is an effect that the amount of eccentricity can be measured with high accuracy regardless of the shape error of the optical element that is the test surface.

  According to the third aspect of the present invention, the relative positional relationship between the reference object and the optical element can be obtained by the first positional relationship measurement step. Furthermore, the relative positional relationship between the reference object and the frame can be obtained by the second positional relationship measurement step. And the eccentric amount with respect to the frame of an optical element is computable by the eccentric amount calculation process. As a result, according to the present invention, there is an effect that the amount of eccentricity can be measured with high accuracy regardless of the shape error of the optical element that is the test surface.

  Embodiments of a lens frame and a three-dimensional shape measuring method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 shows a cross-sectional configuration of a lens frame 10 according to the first embodiment of the present invention. The lens frame 10 is, for example, an imaging optical system for a camera having a zoom function and a focus function. Thus, the “lens frame” refers to a so-called entire configuration of a lens barrel including an optical element and a mechanism for holding the optical element. The lens frame 10 includes a moving frame 130 and a fixed frame 140. A mount 140 d is formed at the end of the fixed frame 140. The fixed frame 140 is fixed to the mounting portion 160 via the mount 140d. The moving frame 130 is supported by a driving mechanism (not shown) so as to be movable in the direction along the optical axis (Z axis) with respect to the fixed frame 140. Note that the fixed frame 140 and the attachment portion 160 correspond to the second frame.

  In FIG. 1, the design optical axis direction of the lens frame 10 is the Z axis, the direction orthogonal to the Z axis is the X axis, and the direction orthogonal to the Z axis and the X axis is the Y axis. Further, the rotation direction with the Z axis as the rotation center is defined as the θ axis. The attachment portion 160 and the fixed frame 140 are united and can be rotated in the θ direction by a rotation drive portion (not shown) around a reference axis 160a parallel to the Z axis. For simplicity, the reference axis 160a and the optical axis are treated as being coincident. In addition, the attaching part 160 can stop rotation operation in arbitrary positions. Further, the rotary encoder (not shown) outputs a rotation angle θ in the θ direction between the attachment portion 160 and the fixed frame 140.

  In addition, three lenses 100, 110, and 120 that are optical elements are arranged inside the moving frame 130. First, the lens 100 will be described. FIG. 3A shows a cross-sectional configuration for holding the lens 100. 3-2 shows a front configuration of the lens 100 viewed from the direction of the reference axis 160a. 3A, the front surface 100a and the back surface 100b of the lens 100 are spherical or aspherical surfaces, respectively. The lens 100 is held on the inner periphery of the lens frame 100c. The lens frame 100c corresponds to the first frame. As shown in FIG. 3-2, at least three spheres 100d, 100e, and 100f, which are reference objects, are formed at substantially equal intervals on the outer periphery of the lens frame 100c. Further, three cam pins 100g are formed between the three balls 100d, 100e, and 100f, respectively. Each of the three spheres 100d, 100e, and 100f has a shape of a sphere having a high sphericity or a part of a sphere having a high sphericity, for example, a hemisphere. The three spheres 100d, 100e, and 100f can be configured to be directly fixed to the lens frame 100c by bonding or the like, or to be detachably attached by screws or the like. Furthermore, when the lens frame 100c is a molded product, the three spheres 100d, 100e, and 100f may be integrally molded at the same time.

  As shown in FIG. 1, the lens 110 is also a lens in which the front surface 110 a and the back surface 110 b are spherical or aspherical, like the lens 100. The lens 110 is held on the inner periphery of the lens frame 110c. The lens frame 110c corresponds to the first frame. In addition, at least three spheres 110d, 110e, and 110f, which are reference objects, are formed on the outer periphery of the lens frame 110c at substantially equal intervals. In FIG. 1, only the sphere 110d is shown, and the other two spheres are omitted. Further, three cam pins 110g are formed between the three balls 110d, 110e, and 110f, respectively.

  Similarly to the lens 100, the lens 120 is a lens in which the front surface 120a and the back surface 120b are spherical or aspherical. The lens 120 is held on the inner periphery of the lens frame 120c. The lens frame 120c corresponds to the first frame. In addition, at least three spheres 120d, 120e, and 120f, which are reference objects, are formed on the outer periphery of the lens frame 120c at substantially equal intervals. In FIG. 1, only the sphere 120d is shown, and the other two spheres are omitted. Further, three cam pins 120g are formed between the three balls 120d, 120e, and 120f, respectively.

  Further description will be continued with reference to FIG. Spiral or linear cam grooves 130 a and 130 b are formed on the inner peripheral portion of the moving frame 130. Similarly, a cam groove 140 a is formed in the inner peripheral portion of the fixed frame 140. The tip of the cam pin 100g of the lens 100 and the tip of the cam pin 110g of the lens 110 are engaged with the cam groove 130a and the cam groove 130b of the moving frame 130, respectively. The tip of the cam pin 120 g of the lens 120 is engaged with the cam groove 140 a of the fixed frame 140. The lens 100, 110, 120 is moved to a predetermined position in the lens frame 10 by a driving mechanism (not shown) in the lens frame 10 by a known method including a combination of a cam pin and a cam groove. ) Thus, zooming (magnification operation) and focusing (focusing operation) can be performed. Therefore, there is an effect that the amount of eccentricity at different lens positions can be measured by zooming or focusing.

  Further, the opening 130c is formed in the moving frame 130 at positions facing the three spheres 100d, 100e, and 100f of the lens 100 arranged at predetermined positions. In FIG. 1, only one opening 130c is shown, and the other two openings are not shown. In addition, three openings 130f are formed at positions facing the three balls 110d, 110e, and 110f of the lens 110. In FIG. 1, only one opening 130f is shown, and the other two openings are not shown.

  In addition, three openings 140b are formed in the fixed frame 140 at positions facing the three balls 110d, 110e, and 110f of the lens 110, respectively. Further, three openings 140e are formed in the fixed frame 140 at positions facing the three spheres 120d, 120e, and 120f of the lens 120, respectively.

  Next, the procedure of the eccentricity measuring method using the above-described lens frame 10 will be described. FIG. 6 is a flowchart illustrating the procedure of the eccentricity measuring method according to the present embodiment. First, in the procedure from step S601 to step S605, measurement is performed in a single state before the lens frames 100c, 110c, and 120c are incorporated into the lens frame 10. Next, after the measurement with the lens frame alone, the lens frames 100 c, 110 c and 120 c are incorporated into the lens frame 10. Then, in the procedure from step S606 to step S609, the lens frames 100c, 110c, and 120c that are incorporated in the lens frame 10 are measured.

  The measurement with the lens frames 100c, 110c, and 120c alone will be described. The same measurement procedure is performed for each of the three lens frames 100c, 110c, and 120c. For this reason, the lens frame 100c will be described as a representative example. Since the lens frames 110c and 120c are duplicated, description thereof is omitted. The lens frames 100c, 110c, and 120c correspond to the first frame.

  First, the eccentricity measurement of the front surface 100a and the back surface 100b of the lens 100 is performed. For the eccentricity measurement between the front surface 100a and the rear surface 100b of the lens 100, a three-dimensional shape measuring machine equipped with a contact probe is used. As a shape measurement method using a three-dimensional shape measuring machine, for example, methods disclosed in Japanese Patent Application Laid-Open Nos. 2000-46543 and 2002-71344 are used. For example, the three-dimensional shape measuring machine includes a laser length measuring optical system and a probe 170 (see FIG. 2). In the XYZ coordinate system shown in FIG. 3A, the laser measuring optical system and the probe move in the X-axis and Y-axis directions by the X stage and the Y stage. The lens frame 100c is fixed on a surface plate of a three-dimensional shape measuring machine. The probe moves in the Z-axis direction along the surface 100a of the lens 100 of the lens frame 100c. The laser measurement optical system measures the amount of movement of the probe in the Z coordinate direction by a known interference method. Thus, the three-dimensional shape measuring machine scans the probe in the X-axis and Y-axis directions on the surface to be measured, and obtains a Z-coordinate data string at the XY coordinate position. Then, the shape of the surface to be measured is measured based on the Z coordinate data column.

  Returning to FIG. 6, the description will be continued. In step S601, the shape of the entire surface within the effective range of the surface 100a of the lens 100 and the surface shapes of the three spheres 100d, 100e, and 100f are measured in the same coordinate system. Step S601 corresponds to the first reference object position measuring step and the optical element shape measuring step. Here, the surfaces of the spheres 100d, 100e, and 100f refer to partial regions of the spheres 100d, 100e, and 100f that can be recognized when observed from the same side as the surface 100a of the lens 100. Specifically, when measuring the surface 100a of the lens 100, the surface of the sphere 100d is a hemispherical portion on the same side as the surface 100a of the sphere 100d. The spheres 100d, 100e, and 100f have a diameter of about 0.5 mm to 5 mm. The same applies to the sizes of spheres as all reference objects.

In step S602, the center coordinates of each sphere are calculated based on the surface shape measurement data of the three spheres 100d, 100e, and 100f. Here, according to the high roundness sphere, the center coordinates (curvature center position) can be accurately obtained from the surface shape. Therefore, by using a sphere or a part of a sphere, for example, a hemispherical shape as the reference object, the center coordinates can be easily and accurately calculated. Since the three spheres 100d, 100e, and 100f are also spheres having a high roundness, highly accurate coordinate measurement can be performed in this embodiment. Next, using the calculated center coordinates of the three spheres, a surface measurement coordinate system (X _1a , Y _1a , Z _1a ) related to the lens frame 100c is determined as shown in FIG. Further, the shape measurement data of the surface 100a of the lens 100 is coordinate-converted into a surface measurement coordinate system (X _1a , Y _1a , Z _1a ). Then, the shape and normal vector (x _a , y _a , z _a ) of the surface 100a of the lens 100 are calculated. Step S602 corresponds to a measurement coordinate system calculation step regarding the surface 100a.

  Next, in step S603 of FIG. 6, the back surface 100b side of the lens 100 is measured in the same manner as the front surface 100a. Therefore, the lens 100 is inverted and the back surface 100b is disposed so as to face the probe of the three-dimensional shape measuring machine. The shape of the entire back surface 100b of the lens 100 within the effective range and the shapes of the back surfaces of the three spheres 100d, 100e, and 100f are measured in the same coordinate system. Step S603 corresponds to the first reference object position measuring step and the optical element shape measuring step. Here, the back surfaces of the spheres 100d, 100e, and 100f refer to partial areas of the spheres 100d, 100e, and 100f that can be recognized when observed from the same side as the back surface 100b of the lens 100. For example, when measuring the back surface 100b of the lens 100, the back surface of the sphere 100d is a hemispherical portion on the same side of the sphere 100d as the back surface 100b.

In step S604, the central coordinates of each sphere are calculated based on the shape measurement data of the back surfaces of the three measured spheres 100d, 100e, and 100f (the surface opposite to the surface measured in step S601). Next, using the calculated center coordinates of the three spheres, a back surface measurement coordinate system (X _1b , Y _1b , Z _1b ) is determined as shown in FIG. Further, the shape measurement data of the back surface 100b of the lens 100 is coordinate-converted into the back surface measurement coordinate system (X _1b , Y _1b , Z _1b ). The shape and the normal vector of the rear surface 100b of the lens _{100 (x b, y b,} z b) is calculated. Step S604 corresponds to the measurement coordinate system calculation step for the back surface 100b.

The three spheres 100d, 100e, and 100f each have a high sphericity. For this reason, the center position of the front surface and the center position of the back surface are the same. In step S605, using the data calculated in steps S602 and S604, as shown in FIG. 4-3, the front surface measurement coordinate system and the back surface measurement coordinate system are set to the same coordinate system (X ₁ , Y ₁ , The coordinates are converted into Z ₁ ). In this coordinate system (X ₁ , Y ₁ , Z ₁ ), the shape and normal vector (X _a , Y _a , Z _a ) of the front surface 100a of the lens 100 and the shape and normal vector (X _b , The positional relationship of Y _b , Z _b ) is calculated. Thereby, the relative positional relationship between the front surface 100a and the rear surface 100b of the lens 100 with respect to the coordinate system (X ₁ , Y ₁ , Z ₁ ) determined by the three spheres 100d, 100e, 100f, that is, the amount of eccentricity can be obtained. . Step S605 corresponds to a coordinate transformation calculation process.

  With respect to the lens frame 110c and the lens frame 120c, the measurement from step S601 to S605 is performed in the same procedure as the lens frame 100c while holding the lenses 110 and 120, respectively. Thereby, the relative positional relationship in the lens frames 100c, 110c, and 120c can be calculated for the three lenses 100, 110, and 120, respectively.

  Next, in step S606, the three lens frames 100c, 110c, and 120c are assembled into the lens frame 10. Thereby, the lens frame 10 becomes a structure as an imaging optical system as shown in FIG. Step S606 corresponds to a support process. Also in the following steps S607 to S609, the three-dimensional shape measuring machine having the contact probe described above is used.

  In step S607, a sphere that is a reference object of the lens frames 100c, 110c, and 120c holding the lenses 100, 110, and 120 is measured. Step S607 corresponds to the second reference object position measuring step. The same measurement procedure is performed for each of the three lens frames 100c, 110c, and 120c.

  FIG. 2 shows a configuration in the vicinity of the lens frame 100c when the measurement related to the lens frame 100c is performed. The illustration of the configuration of the fixed frame 140, the attachment portion 160, and the like is omitted. The mounting portion 160 (see FIG. 1) is rotated in the θ direction so that the outer peripheral surface of the sphere 100d of the lens frame 100c faces the probe 170 of a three-dimensional shape measuring machine (not shown). An opening 130c is formed at the position of the moving frame 130 facing the sphere 100d. Similarly, openings (not shown) are also formed at the positions of the moving frame 130 facing the remaining two spheres 100e and 100f. Thus, by providing the opening in the moving frame 130 (corresponding to the second frame), there is an effect that a contact type three-dimensional shape measuring machine can be used.

  Next, the stylus 170a of the probe 170 of the three-dimensional shape measuring machine is brought into contact with the surface of the sphere 100d through the opening 130c of the moving frame 130. The probe 170 is scanned in the XY coordinate plane and moved in the Z-axis direction along the shape of the sphere 100d. The amount of movement of the stylus 170a is measured by a laser measuring optical system (not shown). Thereby, the shape of the outer peripheral surface of the sphere 100d is measured.

  Thereafter, the mounting portion 160 is rotated around the reference axis 160a so that the other sphere 100e of the lens 100 faces the probe 170. Then, the shape of the outer peripheral surface of the second sphere 100 e is measured by the probe 170 through another opening (not shown) of the moving frame 130. Further, the mounting portion 160 is rotated around the reference axis 160 a so that the other sphere 100 f of the lens 100 faces the probe 170. Then, the shape of the outer peripheral surface of the third sphere 100 f is measured by the probe 170 through another opening (not shown) of the moving frame 130. Here, the outer peripheral surfaces of the spheres 100d, 100e, and 100f are the surface areas of a part of the spheres 100d, 100e, and 100f that are orthogonal to the reference axis 160a and that are visible from the outside in the radial direction passing through the centers of the spheres 100d, 100e, and 100f. Say.

  The size of the area where the stylus 170a contacts will be described. FIG. 10 shows the sphere 100d in an enlarged manner. Consider an axis XG that is substantially perpendicular to the lens frame 100c (reference axis 160a) and passes through the center CT of the sphere 100d. It is desirable that the angle θS at which the center CT is viewed with respect to the axis XG satisfies the condition of 20 ° ≦ θS ≦ 45 °. By measuring such a region with the stylus 170a, the position of the center CT can be calculated with high accuracy.

  Returning to FIG. 1, the description will be continued. Following the measurement of the outer peripheral surfaces of the three spheres 100d, 100e, and 100f of the lens 100, the three spheres 110d, 110e, and 110f of the second lens frame 110c (two of 110e and 110f are not shown). Measure the outer periphery shape. An opening 130f (the other two openings are not shown) is formed at the position of the moving frame 130 facing the sphere 110d. Similarly, an opening 140b (the other two openings are not shown) is formed at the position of the fixed frame 140 facing the sphere 110d. Then, the shape of the outer peripheral surface of the first sphere 110 d is measured by the probe 170 through the opening 140 b of the fixed frame 140 and the opening 130 f of the moving frame 130.

  Thereafter, the mounting portion 160 is rotated around the reference axis 160a so that the second sphere 110e (not shown) of the lens 110 faces the probe 170. Then, the shape of the outer peripheral surface of the second sphere 110 e is measured by the probe 170 through another opening (not shown) of the fixed frame 140 and the moving frame 130. Further, the mounting portion 160 is rotated around the reference axis 160 a so that the third sphere 110 f (not shown) of the lens 110 faces the probe 170. Then, the shape of the outer peripheral surface of the third sphere 110 f is measured by the probe 170 through still another opening (not shown) of the fixed frame 140 and the moving frame 130.

  Following the measurement of the shape of the outer peripheral surface of the three spheres 110d and the like of the lens 110, the outer peripheral shape of the three spheres 120d, 120e and 120f (two of 120e and 120f are not shown) of the third lens frame 120c. Measure. An opening 140e (the other two openings are not shown) is formed at the position of the fixed frame 140 facing the sphere 120d. Then, the shape of the outer peripheral surface of the first sphere 120 d is measured by the probe 170 through the opening 140 e of the fixed frame 140.

  Thereafter, the mounting portion 160 is rotated around the reference axis 160a so that the second sphere 120e (not shown) of the lens 120 faces the probe 170. Then, the shape of the outer peripheral surface of the second sphere 120 e is measured by the probe 170 through another opening (not shown) of the fixed frame 140. Further, the mounting portion 160 is rotated around the reference axis 160 a so that the third sphere 120 f (not shown) of the lens 120 faces the probe 170. Then, the shape of the outer peripheral surface of the third sphere 120 f is measured by the probe 170 through another opening (not shown) of the fixed frame 140.

In step S608, the center coordinates of each sphere are calculated from the shape measurement data of the outer peripheral surfaces of the three spheres 100d, 100e, and 100f of the lens 100 measured in step S607. Then, using the calculated center coordinates of the three spheres 100d, 100e, and 100f, as shown in FIG. 5, the lens 100 with respect to the measurement coordinate system (X, Y, Z) determined by the reference axis 160a and the θ axis is used. The amount of eccentricity of the coordinate system (X ₁ , Y ₁ , Z ₁ ) determined by the three spheres 100d, 100e, 100f is calculated. Step S608 corresponds to the first frame eccentricity calculation step.

Similarly, the amount of eccentricity of the coordinate system (X ₂ , Y ₂ , Z ₂ ) determined by the three spheres 110d of the lens 110 with respect to the measurement coordinate system (X, Y, Z) is calculated. Further, the amount of eccentricity of the coordinate system (X ₃ , Y ₃ , Z ₃ ) determined by the three spheres 120d of the lens 120 with respect to the measurement coordinate system (X, Y, Z) is calculated.

Here, the three spheres of the lenses 100, 110, and 120 each have a high sphericity. For this reason, the center position of the front surface, the center position of the back surface, and the center position of the outer peripheral surface are the same. As described above, in step S605, the amount of eccentricity between the front surface 100a and the rear surface 100b of the lens 100 on the coordinate system (X ₁ , Y ₁ , Z ₁ ) is obtained. Further, in step S608, the amount of eccentricity of the coordinate system (X ₁ , Y ₁ , Z ₁ ) on the measurement coordinate system (X, Y, Z) is obtained. Thereby, in step 609, the amount of eccentricity between the front surface 100a and the rear surface 100b of the lens 100 with respect to the measurement coordinate system (X, Y, Z) can be calculated. Step S609 corresponds to an optical element eccentricity calculation step. Similarly to the lens 100, the amount of eccentricity between the front surface 110a and the back surface 110b of the lens 110 on the measurement coordinate system (X, Y, Z) can be calculated. Further, in the same manner as the lens 100, the amount of eccentricity between the front surface 120a and the back surface 120b of the lens 120 on the measurement coordinate system (X, Y, Z) can be calculated.

  According to the present embodiment, the amount of eccentricity (the shape of the test surface and the normal vector) of the lenses 100, 110, and 120 arranged at predetermined positions in the lens frame 10 is used to measure the shape of the entire effective range of each lens surface. Seeking from data. Therefore, even when a shape error exists on the lens surface, it is possible to obtain lens surface shape measurement data including the shape error. Then, the normal vector can be obtained from the lens surface shape measurement data. Therefore, even if a shape error exists on the lens surface, the eccentricity can be calculated in consideration of the shape error without being affected by the shape error. The lens surface may be either spherical or aspherical.

  In this embodiment, the lenses 100, 110, and 120 are measured as single lenses (steps S 601 to S 605) and the lenses 100, 110, and 120 held at predetermined positions in the lens frame 10 are measured. The same eccentricity measurement (steps S606 to S609) is performed by the same three-dimensional shape measuring machine. For this reason, a single three-dimensional shape measuring machine may be used. As a result, since a plurality of new three-dimensional shape measuring machines are not required, a simple configuration is sufficient.

  FIG. 7 shows a configuration in the vicinity of the lens frame 100c when performing measurement related to the lens frame 100c in the second embodiment of the present invention. The illustration of the configuration of the fixed frame 140, the attachment portion 160, and the like is omitted. In the first embodiment, the surface shape of the lens or reference object is measured using the contact type probe 170. In contrast, the present embodiment is different in that the position of the reference object is measured by a non-contact type laser interferometer. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  An interferometer 180 including a laser light source (not shown) irradiates the sphere 100d with measurement light 180a that is convergent light. Interference fringes generated by reflected light (measurement light) from the sphere 100d and reference light are detected by a detector (not shown). The reference light is reflected light from the reference surface in the interferometer 180. The reference surface has high surface accuracy. The condensing position of the measurement light 180a will be further described.

  FIG. 11 is an enlarged view of the vicinity of the sphere 100d. The surface of the sphere 100d or the like desirably has a radius of curvature comparable to that of the reference surface in the interferometer 180. For this reason, when the reflectance of the sphere 100d or the like is significantly different from the reflectance of the reference surface, it is desirable to form an antireflection film or a reflective film on the surface of the sphere 100d or the like. There are two possible condensing positions for the measurement light. The first focusing position is a so-called cat's eye point CE. The second condensing position is the center of curvature CT of the sphere 100d. The measurement light L1 indicates a state where it is focused on the cat's eye point CE. The measurement light L2 indicates a state of being focused on the curvature center CT. Here, the measurement sensitivity is higher when the measurement light is condensed at the curvature center position CT (center coordinate) than when it is condensed at the cat's eye point CE. Therefore, it is desirable to irradiate the sphere 100d with light that converges to the curvature center position CT such as the measurement light L2.

  When the condensing point of the measurement light 180a and the center of curvature of the sphere 100d having high sphericity exactly coincide with each other, a state in which the interference fringes to be detected are the smallest, that is, a null state of one stripe is obtained. On the other hand, when the condensing point of the measurement light 180a and the center of curvature of the sphere 100d are shifted, interference fringes corresponding to the shift amount are measured. Interferometer 180 is configured to be movable in the Z coordinate direction and the X coordinate direction in FIG. While the interferometer 180 is moved, the state of change of the interference fringes is detected. Then, the position of the interferometer 180 when the interference fringe is in the null state is measured. Thereby, the relative positional relationship between the interferometer 180 and the sphere 100d can be calculated.

  Next, the eccentricity measuring method according to the present embodiment will be described. The measurement procedure from step S601 to S606 is the same as that in the first embodiment. That is, before the lens frames 100c, 110c, and 120c are assembled into the lens frame 10, the surfaces of the lens 100 and the balls 100d, 100e, and 100f that are held are measured with respect to the lens frame 100c by the three-dimensional shape measuring machine. To do. The same measurement is performed for the lens frames 110c and 120c. Next, the three lens frames 100 c, 110 c, and 120 c are incorporated into the lens frame 10.

  In step S607, as shown in FIG. 7, the mounting portion 160 is rotated around the reference axis 160a (θ direction) so that the outer peripheral surface of the sphere 100d of the lens 100 faces the interferometer 180. In this state, the measurement light 180a of the interferometer 180 is applied to the outer peripheral surface of the sphere 100d through the opening 130c of the moving frame 130. The interferometer 180 is moved in the X-axis direction and the Z-axis direction, and the attachment portion 160 is rotated in the θ direction. Then, the position of the interferometer 180 and the rotation angle θ of the mounting portion 160 are finely adjusted so that the interference fringes due to the reflected light on the outer peripheral surface of the sphere 100d are minimized. As described above, in this state, the condensing position of the measurement light from the interferometer 180 and the curvature center position CT of the sphere 100d coincide.

  At this time, the (X, Z) coordinates of the interferometer 180 and the θ coordinates of the mounting portion 160 are measured. The (X, Z) coordinates of the interferometer 180 and the θ coordinates of the mounting portion 160 correspond to the coordinates of the curvature center position CT of the sphere 100d. Next, the mounting portion 160 is rotated around the reference axis 160a (θ direction) so that the second sphere 100e of the lens 100 faces the interferometer 180. And the interference measurement by the reflected light in the outer peripheral surface of the ball | bowl 100e is performed through the other opening part (not shown) of the moving frame 130. FIG. At this time, the position of the interferometer 180 and the rotation angle of the attachment portion 160 are finely adjusted so that the detected interference fringes are minimized. Then, the coordinates of the curvature center position CT of the sphere 100e are measured.

  Further, the mounting portion 160 is rotated around the reference axis 160a (θ direction) so that the third sphere 100f of the lens 100 faces the interferometer 180. Then, the measurement light 180a from the interferometer 180 is subjected to interference measurement by reflected light from the outer peripheral surface of the sphere 100f through still another opening (not shown) of the moving frame 130. At this time, the position of the interferometer 180 and the rotation angle of the attachment portion 160 are finely adjusted so that the detected interference fringes are minimized. Then, the coordinates of the curvature center position CT of the sphere 100f are measured.

  Here, the outer peripheral surfaces of the spheres 100d, 100e, and 100f are the surface areas of a part of the spheres 100d, 100e, and 100f that are orthogonal to the reference axis 160a and that are visible from the outside in the radial direction passing through the centers of the spheres 100d, 100e, and 100f. Say.

  Following the measurement of the curvature center positions of the three spheres 100d, 100e, and 100f of the first lens frame 100c, the second lens frame 110c is measured. As shown in FIG. 1, with respect to the second lens frame 110c, the interferometer 180 interferometrically measures the coordinates of the center of curvature of the sphere 110d through the opening 140b of the fixed frame 140 and the opening 130f of the moving frame 130. Interference measurement is similarly performed on the other two spheres of the second lens frame 110c, and the coordinates of the respective curvature center positions are measured.

  Further, the third lens frame 120 c is measured by the interferometer 180 through the opening 140 e of the fixed frame 140. In this measurement, the coordinates of the center of curvature of the sphere 120d of the lens 120 are subjected to interference measurement. Further, the coordinates of the respective curvature center positions are also measured for the other two spheres by the same interference measurement.

Then, in step S608, as in the first embodiment, using the central coordinate data of the three spheres 100d, 100e, and 100f of the lens 100 measured in step S607, as shown in FIG. The eccentricity of the coordinate system (X ₁ , Y ₁ , Z ₁ ) determined by the three spheres 100d, 100e, 100f of the lens 100 with respect to the measurement coordinate system (X, Y, Z) determined by

Similarly, the amount of eccentricity of the coordinate system (X ₂ , Y ₂ , Z ₂ ) determined by the three spheres 110d of the lens 110 with respect to the measurement coordinate system (X, Y, Z) is calculated. Further, the amount of eccentricity of the coordinate system (X ₃ , Y ₃ , Z ₃ ) determined by the three spheres 120d of the lens 120 with respect to the measurement coordinate system (X, Y, Z) is calculated.

As described above, in step S605, the amount of eccentricity between the front surface 100a and the rear surface 100b of the lens 100 on the coordinate system (X ₁ , Y ₁ , Z ₁ ) is obtained. Further, in step S608, the amount of eccentricity of the coordinate system (X ₁ , Y ₁ , Z ₁ ) on the measurement coordinate system (X, Y, Z) is obtained. Thereby, in step 609, the amount of eccentricity between the front surface 100a and the rear surface 100b of the lens 100 with respect to the measurement coordinate system (X, Y, Z) can be calculated. The same applies to the lenses 110 and 120.

  According to the present embodiment, in the eccentricity measurement between the lenses 100, 110, 120, the center of curvature of each sphere 100d or the like is directly measured by the interferometer 180. For this reason, it is not necessary to measure the shape of the outer peripheral surface of the sphere as a reference object. Therefore, compared to the first embodiment, there is an effect that the eccentricity measurement can be performed in a short measurement time.

  In the present embodiment, the eccentricity of each test surface with respect to the reference axis 160a of the attachment portion 160 is calculated. However, as in the first embodiment, the definition of eccentricity is not limited to this. For example, the amount of eccentricity of each lens surface with respect to a coordinate system defined by the movement axes (X axis and Z axis) of the interferometer 180 may be calculated. Further, in the present embodiment, the lens frame 10 is rotated in the θ direction by the mounting portion 160. However, the present invention is not limited to this. Either the interferometer 180 is rotated in the θ direction around the reference axis 160a, or both the lens frame 10 and the interferometer 180 are relatively rotated in the θ direction. Eccentricity measurement similar to the present embodiment is possible.

(Modification)
Next, a modification of the present embodiment will be described. FIG. 8 is a view of the moving frame 130 in the modification as seen from the X-axis direction. In FIG. 8, the interferometer 180 is omitted. In the lens 100 in the moving frame 130, the three cam pins 100g of the lens frame 100c can move along the cam groove 130a of the moving frame 130 by a moving mechanism (not shown). Thereby, the lens 100 moves in the optical axis direction while rotating in the moving frame 130. At this time, the sphere 100d of the lens frame 100c moves spirally in the direction of the arrow shown in FIG. The opening 130c of the moving frame 130 is configured as a spiral long hole that matches the moving range of the sphere 100d. The other two openings (not shown) of the moving frame 130 have the same spiral long holes. Then, different interferometers are arranged at positions corresponding to the other two spheres of the lens 100, respectively. Thus, in this modification, a total of three interferometers are used.

  Then, the lens 100 is moved with respect to the moving frame 130. The position of the three interferometers and the rotation angle of the attachment portion 160 are adjusted in accordance with the movement of the lens. Here, the positions of the three spheres 100d, 100e, and 100f when the lens 100 is moving are continuously measured for interference by three interferometers. Thereby, it becomes possible to continuously and successively measure the change in the amount of eccentricity accompanying the movement of the lens 100.

  Further, when the lens 100 moves linearly along the optical axis direction within the moving frame 130, the shape of the opening 130c and the like formed in the moving frame 130 is also a long hole having a longitudinal direction along the optical axis direction. To do. Thereby, it becomes possible to continuously and successively measure the change in the amount of eccentricity accompanying the movement of the lens 100. As described above, the present modification has an effect that the change in the amount of eccentricity accompanying the movement in the lens frame 10 can be continuously and successively measured for each lens arranged at a predetermined position in the lens frame 10. .

  FIG. 9 shows a configuration in the vicinity of the lens frame 100c when performing measurement on the lens frame 100c in the third embodiment of the present invention. The illustration of the configuration of the fixed frame 140, the attachment portion 160, and the like is omitted. In the first embodiment, the surface shape of the lens or reference object is measured using the contact type probe 170. On the other hand, the present embodiment is different in that the position of the reference object is measured by the non-contact type magnetic sensor 190. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the present embodiment, the three spheres that are reference objects provided on the outer circumferences of the lens frames 100c, 110c, and 120c are made of a magnetic material, for example, a magnet. In this embodiment, in step S607, a magnetic sensor 190 is used instead of the probe 170 (FIG. 2) of the three-dimensional shape measuring machine. The magnetic sensor 190 detects the strength of the magnetic field. The strength of the magnetic field corresponds to the distance between the sphere 100d formed of a magnet and the magnetic sensor 190. For this reason, the magnetic sensor 190 can detect the distance from the sphere 100d. The magnetic sensor 190 is configured to be movable in the X-axis direction and the Z-axis direction.

  Next, the eccentricity measuring method according to the present embodiment will be described. The measurement procedure from step S601 to S606 is the same as that in the first embodiment. That is, before the lens frames 100c, 110c, and 120c are assembled into the lens frame 10, the surfaces of the lens 100 and the balls 100d, 100e, and 100f that are held are measured with respect to the lens frame 100c by the three-dimensional shape measuring machine. To do. The same measurement is performed for the lens frames 110c and 120c. Next, the three lens frames 100 c, 110 c, and 120 c are incorporated into the lens frame 10.

  In step S607, as shown in FIG. 9, the mounting portion 160 is rotated around the reference axis 160a (θ direction) so that the outer peripheral surface of the sphere 100d of the lens 100 faces the magnetic sensor 190. In this state, the magnetic sensor 190 is moved in the Z-axis direction, and the attachment portion 160 is rotated in the θ direction. Then, the position of the magnetic sensor 190 and the rotation angle θ of the mounting portion 160 are finely adjusted so that the strength of the magnetic field detected by the magnetic sensor 190 is maximized. At this time, the Z coordinate and magnetic field strength of the magnetic sensor 190 and the θ coordinate of the mounting portion 180 are measured.

  The Z coordinate of the magnetic sensor 190 and the θ coordinate of the attachment portion 160 correspond to the direction of the sphere 100d with respect to the reference axis 160a. The strength of the magnetic field corresponds to the distance between the magnetic sensor 190 and the sphere 100d. Thereafter, the mounting portion 160 is rotated in the θ direction around the reference axis 160a so that the second sphere 100e of the lens 100 faces the magnetic sensor 190. The position of the magnetic sensor 190 in the Z-axis direction and the rotation angle of the attachment portion 16 are finely adjusted so that the strength of the magnetic field detected by the magnetic sensor 190 is maximized. Then, the coordinates of the position of the sphere 100e are measured.

  Further, the mounting portion 160 is rotated in the θ direction around the reference axis 160 a so that the third sphere 100 f of the lens 100 faces the magnetic sensor 190. Then, the position of the magnetic sensor 190 in the Z-axis direction and the rotation angle θ of the attachment portion 160 are finely adjusted so that the strength of the magnetic field detected by the magnetic sensor 190 is maximized. Then, the coordinates of the position of the sphere 100f are measured.

  Following the measurement of the position coordinates of the three spheres 100d, 100e, and 100f of the first lens frame 100c, the measurement of the second lens frame 110c is performed. With respect to the second lens frame 110c, the magnetic sensor 190 measures the position coordinates of the sphere 110d in a non-contact manner. Similarly, the other two spheres of the second lens frame 110c are measured in a non-contact manner, and the respective position coordinates are measured.

  Further, with respect to the third lens frame 120c, the magnetic sensor 190 measures the sphere 120d of the lens 120 in a non-contact manner. Further, the position coordinates of the other two spheres are measured by the same non-contact measurement.

In step S608, as in the first embodiment, the position coordinate data of the three spheres 100d, 100e, and 100f of the lens 100 measured in step S607 is used, as shown in FIG. The eccentricity of the coordinate system (X ₁ , Y ₁ , Z ₁ ) determined by the three spheres 100d, 100e, 100f of the lens 100 with respect to the measurement coordinate system (X, Y, Z) determined by

Similarly, the amount of eccentricity of the coordinate system (X ₂ , Y ₂ , Z ₂ ) determined by the three spheres 110d of the lens 110 with respect to the measurement coordinate system (X, Y, Z) is calculated. Further, the amount of eccentricity of the coordinate system (X ₃ , Y ₃ , Z ₃ ) determined by the three spheres 120d of the lens 120 with respect to the measurement coordinate system (X, Y, Z) is calculated.

As described above, in step S605, the amount of eccentricity between the front surface 100a and the rear surface 100b of the lens 100 on the coordinate system (X ₁ , Y ₁ , Z ₁ ) is obtained. Further, in step S608, the amount of eccentricity of the coordinate system (X ₁ , Y ₁ , Z ₁ ) on the measurement coordinate system (X, Y, Z) is obtained. Thereby, in step 609, the amount of eccentricity between the front surface 100a and the rear surface 100b of the lens 100 with respect to the measurement coordinate system (X, Y, Z) can be calculated.

  According to the present embodiment, in the eccentricity measurement between the lenses 100, 110, 120, the position of each sphere is measured by the magnetic sensor 190 through the lens frame 10. For this reason, it is not necessary to provide an opening for measuring eccentricity in the moving frame 130 and the fixed frame 140 constituting the lens frame 10. Therefore, there is an effect that the process of manufacturing the lens frame 10 can be simplified.

  The present invention is not limited to the lens frame 10 having the cam configuration as described above. For example, the lens frame can be configured as a fixed focus optical system in which a lens is fixed to the fixed frame. In this case, there is an effect that it is possible to measure the amount of eccentricity of the fixed focus optical system in the assembled state.

  In each of the above-described embodiments, three spheres are provided on the outer periphery of the lens frames 100c, 110c, and 120c for the lenses 100, 110, and 120 as reference objects. However, the present invention is not limited to this, and four or more spheres may be provided for one lens frame. By increasing the number of spheres that are reference objects, measurement data can be averaged by a plurality of reference objects. As a result, the accuracy of determining each coordinate system can be further improved.

  Further, the reference object is not limited to a sphere or a part of the sphere. For example, the shape of the reference object is not limited as long as the shape can be measured by a three-dimensional shape measuring machine and the shapes of the front surface, the back surface, and the outer peripheral surface of the reference object are known. For example, the reference object may have a rugby ball shape formed of a toric surface.

  In each of the above embodiments, the lens frame 10 holds the three lenses 100, 110, and 120. However, the number of lenses is not limited to this, and any number of lenses may be used. The lens surface may be a free-form surface in addition to a spherical surface and an aspheric surface. Further, even in an optical system including an optical element different from the lens, for example, a prism, a mirror, etc., measurement can be performed in the same manner as in the present embodiment. In addition, it is not always necessary to perform the eccentricity measurement on all the optical elements constituting the lens frame 10. For example, the eccentricity measurement can be performed only for an optical element having a large contribution of the influence of the eccentricity.

  In each of the above embodiments, the eccentric amount of each lens 100, 110, 120 with respect to the reference axis 160 a of the mounting portion 160, that is, the fixed frame 140 is calculated. However, the definition of eccentricity is not limited to this. For example, the eccentric amount of each lens surface may be calculated with respect to the coordinate system of the three-dimensional shape measuring machine. It is also possible to calculate the amount of eccentricity of each lens surface with respect to the optimum axis. As the optimum axis, it is desirable to use an axis that minimizes the sum of squares of the eccentric amounts of the lens surfaces.

  Furthermore, although it has been described that the number of reference objects may be increased to four or more, on the contrary, it may be reduced to two or less. FIGS. 12A and 12B show configuration examples when the number of spheres as reference objects is reduced as compared with the above-described embodiments. In FIG. 12A, the lens frame 100c includes one sphere 100d on the outer periphery. In FIG. 12-2, the lens frame 100c includes two spheres 100d and 100e on the outer periphery. In FIGS. 12A and 12B, the description of the cam pins is omitted. For example, the relative positional relationship between the lens frames 100c, 110c, and 120c and the lenses 100, 110, and 120 may be known in advance. In this case, only the relative positional relationship between the reference axis and each of the lenses 100, 110, 120 needs to be obtained. In such a case, the eccentric amount of each lens surface can be calculated by forming one sphere or two spheres for each lens frame. As described above, the present invention can take various modifications without departing from the spirit of the present invention.

  As described above, the present invention is useful for an eccentricity measuring method, particularly an eccentricity measuring method that always measures the amount of eccentricity with high accuracy regardless of the shape error of the surface to be measured.

FIG. 3 is a diagram illustrating a cross-sectional configuration of a lens frame according to the first embodiment. 2 is a diagram illustrating a configuration in the vicinity of a lens frame of Embodiment 1. FIG. It is a figure which shows the cross-sectional structure of a lens frame single-piece | unit. It is a figure which shows the front structure of a lens frame single-piece | unit. It is a figure which shows the coordinate system regarding the shape measurement of a lens surface. It is a figure which shows the coordinate system regarding the shape measurement of a lens back surface. It is a figure which shows the coordinate system of the surface of a lens, and a back surface. It is a figure which shows the coordinate system of each lens frame in the state which incorporated the lens frame in the mirror frame. 3 is a flowchart illustrating an eccentricity measurement procedure in the first embodiment. 6 is a diagram illustrating a configuration in the vicinity of a lens frame of Embodiment 2. FIG. 6 is a diagram illustrating a configuration in the vicinity of a lens frame according to a modification of Example 2. FIG. 6 is a diagram illustrating a configuration in the vicinity of a lens frame of Embodiment 3. FIG. 3 is an enlarged view showing the vicinity of a sphere of Example 1. FIG. 6 is an enlarged view showing the vicinity of a sphere of Example 2. FIG. It is a figure which shows the modification of arrangement | positioning of a reference | standard thing. It is a figure which shows the other modification of arrangement | positioning of a reference | standard thing. It is a figure explaining the principle of the eccentricity measuring method of a prior art.

Explanation of symbols

100, 110, 120 Lens 100a, 110a, 120a Front surface 100b, 110b, 120b Back surface 100c, 110c, 120c Lens frame 100d, 110d, 120d First sphere 100e, 110e, 120e Second sphere 100f, 110f, 120f Third Sphere 100 g cam pin 130 moving frame 130 a cam groove 130 b cam groove 130 c opening portion 130 f opening portion 140 fixed frame 140 a cam groove 140 b opening portion 140 e opening portion 160 mounting portion 160 a reference shaft 170 probe 170 a stylus 180 interferometer 180 a measuring light 190 magnetic sensor

Claims (14)

A first frame holding an optical element and comprising at least three reference objects;
A lens frame comprising a second frame for supporting the first frame.   The lens frame according to claim 1, wherein the reference object has a spherical or hemispherical shape.   The lens frame according to claim 2, wherein the second frame body has an opening at a position facing the reference object included in the first frame body.   The lens frame according to claim 1, wherein the second frame body supports a plurality of the first frame bodies. A cam pin formed on the outer periphery of the first frame;
A cam groove formed on the inner periphery of the second frame,
2. The lens frame according to claim 1, wherein the first frame is supported so as to be movable in a direction along an optical axis of the optical element with respect to the second frame.   The lens frame according to claim 1, wherein the first frame is fixed to the second frame. A first reference object position measuring step for measuring positions of at least three reference objects provided in the first frame;
An optical element shape measuring step for measuring a shape of a predetermined surface of the optical element held by the first frame;
A measurement coordinate system calculation step of calculating the position of the measurement coordinate system with respect to the first frame based on the measurement result of the first reference object position measurement step;
A coordinate conversion calculation step for converting the measurement result of the optical element shape measurement step into the measurement coordinate system;
A supporting step of supporting the first frame by a second frame;
A second reference object position measuring step for measuring the position of the reference object of the first frame that is supported;
A first frame eccentricity calculating step for calculating an eccentricity with respect to a reference axis of the first frame based on a measurement result of the second reference object position measuring step;
And a decentering amount calculating step of calculating an decentering amount of the optical element with respect to the reference axis.   The eccentricity measuring method according to claim 7, wherein the reference axis is defined by the second frame.   The eccentricity measuring method according to claim 7, wherein the reference object has a spherical or hemispherical shape.   The eccentricity measuring method according to claim 7, wherein the second reference object position measuring step measures the position of the reference object by rotating the second frame body around a predetermined axis.   8. The center position of the reference object is measured by bringing a probe into contact with the reference object in the first reference object position measuring step and the second reference object position measuring step. Eccentricity measurement method.   8. The eccentricity measuring method according to claim 7, wherein, in the second reference object position measuring step, the reference object is irradiated with measurement light by an interferometer to measure the center position of the reference object. The reference object is made of a magnetic material,
The eccentricity measuring method according to claim 7, wherein, in the second reference object position measuring step, the position of the reference object is measured by a magnetic sensor. A first positional relationship measuring step of measuring a positional relationship between at least three reference objects and the optical element;
A second positional relationship measuring step for measuring the positional relationship between the reference object and the frame;
An eccentric amount calculating step of calculating an eccentric amount of the optical element with respect to the frame based on a measurement result of the first positional relationship measuring step and a measurement result of the second positional relationship measuring step. A characteristic eccentricity measuring method.

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