JP2006267085A - Instrument and method for measuring eccentricity of aspherical lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an instrument and a method for measuring easily and precisely an aspherical eccentric amount and direction of an aspherical lens. <P>SOLUTION: The examined lens is rotated, the eccentric amount and direction of the paraxial curvature center are measured from a locus of wobbling around a rotation axis of a spot image formed by a reflected light from an examined face of a light beam converged in the paraxial curvature center, an interval between a lighting optical system and the examined lens is moved to emit the converged beam onto the examined face all the time, a face wobbling amount of the examined face is detected based on a moving amount therein and a detection result of a rotation angle of the examined lens, a detection result of the face wobbling amount is compared with a design data to find a relative shift amount and tilt amount with respect to the rotation axis of a non-examined lens with the difference getting minimum between the both, a face top position of the examined lens with respect o the rotation axis is calculated from the shift amount and the tilt amount, and an inclination amount and a direction of an aspherical axis with respect to an optical axis of the examined lens are calculated based on the face top position, and the eccentric amount and direction of the paraxial curvature center. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an aspheric lens eccentricity measuring apparatus and an eccentricity measuring method for measuring the inclination of an aspherical axis of an aspheric lens.

  Measuring the amount of aspherical eccentricity of an aspherical lens is necessary, for example, when judging the quality of a product in product inspection, and when adjusting the stamping direction of a prototyped aspherical lens. Is also necessary. Here, the aspheric eccentricity of a lens having aspheric surfaces on both sides will be described with reference to FIG. In FIG. 9A, aspherical surfaces 101a and 101b of the aspherical lens 100 as the test lens indicated by solid lines are surfaces designed with reference to the paraxial spherical surfaces 102a and 102b indicated by phantom lines. A line Ax connecting the centers of curvature oa and ob of the paraxial spherical surfaces 102 a and 102 b is the optical axis of the aspherical lens 100. Further, the aspherical surface axis Axa connecting the apex (surface apex) tb of the aspherical surface 101a and the center of curvature ob of the paraxial spherical surface 102a, and the apex (surface apex) tb of the aspherical surface 101b and the center of curvature oa of the paraxial spherical surface 102b, There are two aspherical axes, the aspherical axis Axb connecting the two. If the aspherical lens is manufactured as designed, the three axes of the optical axis Ax, the aspherical axis Axa, and the aspherical axis Axb are completely coincident with each other, but it is actually difficult to manufacture such a lens. It is.

  When the three axes of the optical axis Ax, the aspherical axis Axa, and the aspherical axis Axb are shifted, the aspherical surfaces 101a and 101b are inclined from the ideal state, and the optical axis Ax, the aspherical axis Axa, and the aspherical axis Axb are , Respectively intersecting the optical axis at angles εa and εb. The angle εa (tilt) at this time is the aspheric eccentricity of the aspherical surface 101a, and the angle εb (tilt) is the aspherical eccentricity of the aspherical surface 101b. As shown in FIGS. 9B and 9C, the direction from the origin to the top of the aspheric surface (the top of the aspheric surface) is the direction of the aspheric surface decentering with respect to the optical axis (that is, the aspheric surface 101a). The direction of the aspheric eccentricity is θεa, and the direction of the aspherical eccentricity of the aspherical surface 101b is θεb). Here, the angles εa and εb are when the aspheric eccentricity is defined as tilt, but it is also possible to define the aspheric eccentricity as shift. In this case, the length δa of the perpendicular when the perpendicular is dropped from the aspheric surface top ta to the optical axis Ax, and the length of the perpendicular when the perpendicular is dropped from the aspheric surface top tb to the optical axis Ax. δb is an aspheric eccentricity defined by shift. When such an aspherical lens is manufactured, in order to evaluate the completed lens, it is necessary to first measure the aspherical eccentricity and direction, and then perform product evaluation and mold correction.

FIG. 10 shows a schematic configuration of an eccentricity measuring apparatus for measuring the eccentricity of a conventional aspheric lens.
As shown in FIG. 10, a conventional eccentricity measuring apparatus 200 includes a lens receiving portion 300 that holds the lens 100 to be tested, a rotating lens support member 400 that rotatably supports the lens receiving portion 300, and an unillustrated portion. It has a light source and optical components such as an irradiation optical system and an image sensor. Further, the lens 100 includes a paraxial decentering measurement unit 500 that detects the decentering amount and direction of the paraxial curvature center of the lens 100 to be tested, and a laser light source interference optical system (not shown). A test surface shape measurement unit 600 is provided at a position away from the paraxial eccentricity measurement unit 500 and detects the shape of the test surface of the test lens 100 from the state of change in interference fringes. At the time of measuring the eccentricity of the aspherical lens, the test lens 100 is rotated and the data obtained by the measurement by the test surface shape measuring unit 600 is compared with the design formula of the test surface of the test lens 100. Then, the relative shift amount and tilt amount that minimize the difference between the two are obtained, and the position of the surface top of the test lens 100 with respect to the rotating shaft 900 is measured from the shift amount and tilt amount, and the position close to the position of the surface top The decentering measurement of the aspherical lens for calculating the tilt amount and direction of the spherical axis with respect to the optical axis of the test lens 100 from the decentering amount and direction of the paraxial curvature center of the test lens measured by the shaft decentering measurement unit 500 An apparatus has been proposed (see, for example, Patent Document 1).

JP 2003-156405 A

  However, in such a conventional aspherical lens decentration measuring device, it is necessary to individually adjust the optical alignment of the paraxial decentering measurement unit and the test surface shape measurement unit, and the measurement reference point, respectively. As the number of measurement steps increased, there was a limit to improving measurement accuracy.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems of the prior art, and to provide an eccentricity measuring apparatus and an eccentricity measuring method capable of measuring the amount and direction of an aspherical surface of an aspherical lens easily and with high accuracy. And

  In order to achieve the above object, the aspherical lens decentration measuring apparatus of the present invention is an aspherical lens decentration measuring apparatus, which comprises a lens holding member that holds a lens to be examined, and a rotation of the holding member. Rotating means, an illumination light source, an illumination optical system that irradiates the test surface of the test lens with light from the illumination light source, and an imaging optical system that forms an image of reflected light from the test surface of the test lens And an image detecting means for detecting an image formed by the imaging optical system, and an optical axis direction moving means capable of moving a relative position in the optical axis direction of the illumination optical system with respect to the lens holding member. The light beam collected at the center of the paraxial curvature of the test surface of the test lens is detected by the image detecting means, and the rotation of the detected light flux from the trajectory around the rotation axis of the rotating means is detected. Eccentricity and eccentricity of the paraxial center of curvature with respect to the axis An eccentric state calculation unit for calculating a direction, and the illumination optical system and the lens holding member by the optical axis direction moving unit so that a light beam from the illumination optical system is collected on a test surface of the test lens. And the relative movement amount of the illumination optical system and the lens holding member and the rotation angle of the rotating means are detected, and the surface runout in the direction of the rotation axis of the surface to be detected is detected based on the detection result. A surface shake amount detection unit for detecting the amount, a surface shake amount of the test surface detected by the surface shake amount detection unit, an eccentric amount and an eccentric direction of the paraxial curvature center calculated by the eccentric state calculation unit, And aspheric decentering amount calculating means for calculating the inclination amount and direction of the aspheric axis with respect to the optical axis of the lens to be examined.

  In order to achieve the above object, in the method for measuring the decentration of an aspheric lens according to the present invention, the illumination light from the illumination optical system is irradiated on the test surface of the test lens, and the test surface is A decentering method of an aspherical lens that detects the reflected light of the aspherical lens and measures the tilt amount and direction of the aspherical axis with respect to the optical axis of the lens to be examined. The rotation axis of the spot image formed by the reflected light from the test surface is irradiated while irradiating the test surface of the test lens so as to focus on the paraxial curvature center of A step of measuring the decentering state of the paraxial curvature center for measuring the decentering amount and decentering direction of the paraxial curvature center with respect to the rotation axis from the locus of the detected spot image, While rotating, the light beam from the illumination optical system is focused on the surface to be examined. The distance between the illumination optical system and the test lens is changed at any time, the relative movement amount of the illumination optical system and the test lens and the rotation angle of the test lens are detected, and the test object is detected based on the detection result. A surface runout amount detecting step for detecting a surface runout amount in the rotation axis direction of the test surface, and a surface runout amount of the test surface detected by the surface runout amount detecting step are compared with the design data of the test surface. Determining the relative shift amount and tilt amount with respect to the rotation axis that minimizes the difference between the two, the top position of the surface to be measured with respect to the rotation axis calculated from the shift amount and tilt amount, and the eccentric state An aspheric eccentricity calculating step for calculating an inclination amount and direction of the aspherical axis with respect to the optical axis of the lens to be measured from the eccentric amount and the eccentric direction of the paraxial curvature center measured by the measuring step. It is characterized by.

  As described above, according to the eccentricity measuring apparatus and the eccentricity measuring method of the present invention, it is possible to easily and accurately measure the aspherical eccentric amount and the direction of the aspherical lens.

  Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.

<Eccentricity measuring device>
FIG.1 and FIG.2 is schematic explanatory drawing of the eccentricity measuring apparatus 1 which concerns on this Embodiment. 7 and 8 are schematic configuration explanatory views showing a modification of the eccentricity measuring apparatus 1 according to the present embodiment. In addition, about the same structure, the same code | symbol is attached | subjected and description is abbreviate | omitted.
In the decentration measuring apparatus 1 according to the present embodiment, a lens holding member 20 that holds a test lens 10 and a surface opposite to the lens holding surface 21 of the lens holding member 20 are connected, and the lens holding member 20 is connected. A rotating means 30 for rotating the lens, an autocollimation measuring unit 50 arranged at a predetermined interval from the test surface 10b of the lens 10 placed on the lens holding member 20, control of each part in the eccentricity measuring device and predetermined And a control / arithmetic unit 70 that performs the above-described calculation, and other configurations appropriately selected.

  As shown in the cross section of FIG. 1, the lens holding member 20 has a cylindrical shape, and the inner peripheral edge on the upper end side in the drawing contacts the test lens 10 so that the test lens 10 is positioned. A flange portion is formed on the lower end side of the lens holding member 20. The lens holding member 20 and the rotating means 30 are coaxially connected by the lower end side flange portion of the lens holding member 20. The rotating means 30 includes a motor (not shown) as a drive source. Further, a rotary encoder 40 is connected to a drive shaft of a motor (not shown) of the rotating means 30, and the rotational angle of the rotating means 30 can be detected by the rotary encoder 40.

  The autocollimation method measuring unit 50 includes an illumination light source 51, illumination optical systems 52 a and 52 b that irradiate the test surface of the test lens 10 with the light from the illumination light source 51 as a condensing light beam, and the test lens 10. Imaging optical systems 53a and 53b that image reflected light from the test surface, image detection means 54 that detects images formed by the imaging optical systems 53a and 53b, and at least illumination optical systems 52a and 52b The distance from the lens holding member 20 can be changed relatively in the optical axis direction, and the irradiation position of the light beam condensed by the illumination optical systems 52a and 52b on the test lens 10 in the optical axis L direction can be changed. The light beam condensed by the illumination optical systems 52a and 52b so that the optical axis direction moving means 55, the illumination optical systems 52a and 52b, and the lens holding member 20 can be moved relative to each other in the direction orthogonal to the optical axis L direction. Optical axis L The horizontal direction moving means 56 capable of changing the irradiation position on the test surface of the test lens 10 in the orthogonal direction, and the light emitted from the illumination light source 51 provided in the optical path of the illumination optical systems 52a and 52b are tested. A half mirror 57 that transmits toward the lens 10 and reflects reflected light from the test surface of the test lens toward the image detection unit 54 is provided.

  The autocollimation measuring unit 50 is preferably housed in the housing 50 </ b> A, and the entire housing 50 </ b> A is preferably attached to the column 57. Further, the autocollimation measuring unit 50 shown in the present embodiment shares the positive lens 52b that forms part of the illumination optical system and the positive lens 53b that forms part of the imaging optical system.

  Although there is no restriction | limiting in particular as the illumination light source 51, For example, a laser diode, a semiconductor laser, etc. are mentioned suitably.

  The illumination optical system is not particularly limited as long as it can condense light from the illumination light source 51 on the test surface or the center of the paraxial curvature of the test surface of the test lens 10, and is shown in FIG. In addition to the configuration including the two positive lenses 52a and 52b arranged to face each other at a predetermined interval, a lens including a plurality of lens groups may be used. The imaging optical system may include a plurality of lens groups in addition to the configuration including the two positive lenses 53 a and 53 b disposed 90 ° via the half mirror 57. Further, as the image detecting means 54 disposed at the image forming position of the lens 53a constituting the image forming optical system, a normal image pickup device such as a CCD can be used.

  As the optical axis direction moving means 55 (55A, 55B), as long as the irradiation position of the light beam condensed by the illumination optical systems 52a, 52b on the lens 10 in the optical axis L direction can be changed, Although there is no particular limitation, for example, as shown in FIG. 1, the optical axis direction moving means 55A can move the position of the positive lens 52b on the test lens 10 side in the illumination optical systems 52a and 52b in the optical axis L direction. Thus, a configuration that can change the irradiation position of the light beam on the test lens 10 in the direction of the optical axis L is preferable.

  As a modification of the optical axis direction moving means 55, as shown in FIG. 7, the lenses 52a and 52b constituting the illumination optical system are fixed, and the optical axis direction moving means 55B uses the autocollimation method measuring unit 50. A configuration in which the casing 50 </ b> A is movable with respect to the column 57 in parallel with the direction of the optical axis L is preferable. Here, a known slide guide or the like can be used as the moving mechanism of the positive lens 52b or the housing 50A. Further, the optical axis direction moving means 55 can be controlled remotely by using a motor or the like. Further, the lens holding means 20 side may be moved with respect to the housing 50A.

  In this case, it is possible to prevent the influence of the measurement error due to the variation in the distance between the lenses 52a and 52b constituting the illumination optical system, and it is possible to improve the measurement accuracy.

  The horizontal moving means 56 may be configured to change the irradiation position on the test surface of the test lens 10 in the direction orthogonal to the optical axis L of the light beam collected by the illumination optical systems 52a and 52b. For example, as shown in FIG. 1, for example, a configuration in which the housing 50 </ b> A is movable in a direction orthogonal to the optical axis L is preferable. Moreover, as the horizontal direction moving means 56, the movement control can be performed by remote operation using a motor or the like. Further, the lens holding means 20 side may be moved with respect to the housing 50A. By the optical axis direction moving means 55 and the horizontal direction moving means 56, the light beams from the illumination optical systems 52 a and 52 b are focused on the test surface of the test lens 10 so as to be condensed at a predetermined position of the test lens 10. A predetermined position is irradiated. Here, when calculating the amount of decentration and the direction of decentering of the paraxial curvature center with respect to the rotation axis M of the test surface of the test lens 10, the light beams from the illumination optical systems 52a and 52b are paraxial on the test surface. The light is irradiated to a predetermined position on the test surface of the test lens 10 so as to be condensed at the center of curvature. In addition, when detecting the surface shake amount in the direction of the rotation axis M of the test surface of the test lens 10, the light beams from the illumination optical systems 52a and 52b are condensed at a predetermined position on the test surface. Irradiated as follows.

  The image detection means 54 detects the reflected light from the test surface of the light beam irradiated on the test surface of the test lens 10 as a spot image.

  The control / arithmetic unit 70 includes an eccentric state calculation unit, a surface shake amount detection unit, and an aspherical eccentricity calculation unit (not shown).

  The eccentric state calculation unit is detected by the image detection means 54 in a state where the illumination optical systems 52a and 52b are arranged so that the light beam from the illumination light is collected at the paraxial curvature center 1ob (1oa) of the surface to be measured. The amount of eccentricity and the direction of eccentricity of the paraxial center of curvature 1ob (1oa) with respect to the rotation axis M of the rotation means 30 are calculated from the locus of the spot image rotating about the rotation axis M of the rotation means 30.

  The surface shake amount detector is connected to the illumination optical system by the optical axis direction moving means 55A or 55B so that the light beam from the illumination optical systems 52a and 52b is always irradiated onto the test surface of the test lens 10. The relative distance between the illumination optical system and the lens holding member 20 and the rotation angle of the rotating means 30 are detected by appropriately changing the distance between the lens holding member 20 and the rotation axis of the test surface based on the detection result. Detects the amount of surface runout in the direction. The rotation angle of the rotating means 30 is detected by the rotary encoder 40, and the detection signal is input to the control / arithmetic unit 70 as an output signal.

  The aspherical surface eccentricity calculating means compares the surface runout amount of the test surface detected by the surface shake amount detecting unit with the design data of the test surface, and the rotation of the rotating means 30 that minimizes the difference between the two. The relative shift amount and tilt amount with respect to the axis M are obtained, the surface top position of the test surface with respect to the rotation axis M is calculated from the shift amount and tilt amount, and the calculated surface top position and the eccentricity are calculated. From the decentering amount and decentering direction of the paraxial curvature center calculated by the state calculating unit, the tilt amount and direction of the aspherical axis with respect to the optical axis of the lens 10 to be tested are calculated.

  As another configuration of the eccentricity measuring apparatus 1 according to the present embodiment, a monitor 80 is preferably exemplified. The monitor 80 can display, for example, a spot image detected by the image detection means 54, displays the swing of the spot image around the rotation axis M of the rotation means 30, and the later-described lens of the test lens. This is used for a centering adjustment process or when a spot image is moved to the paraxial curvature center 1ob of the test surface of the test lens 10.

  In the above description, the test lens 10 has been described as a test lens having a convex aspherical shape on both sides of the lens. However, the lens 10 has a spherical surface on one side and an aspherical surface on the other side. In addition, the present invention can also be applied to a lens having a concave aspherical surface or a spherical surface on both sides or one side of the lens.

<Eccentricity measuring method>
Next, the eccentricity measuring method according to the embodiment of the present invention will be described. The method for measuring the decentration of the aspherical lens described below will be described for a test lens having a convex aspherical shape on both surfaces of the lens. However, as described above, the same measurement is also performed for aspherical lenses having other shapes. It is possible to adapt the method.
An aspheric lens decentration measuring method according to an embodiment of the present invention includes a decentered state measuring step of a paraxial curvature center, a surface shake amount detecting step, and an aspheric decentering amount calculating step, and further if necessary. Other steps such as a substantially centering adjustment step and a centering adjustment step are provided.

<< About the centering adjustment process >>
In the approximate centering adjustment step, in the eccentricity measuring apparatus 1 shown in FIG. 1, after the test lens 10 is supported by the lens holding member 20, the test lens 10 is centered while being rotated by the rotating means 30. It is. If the test lens 10 is simply placed on the lens holding member 20, it is tilted or displaced with respect to the rotation axis M of the rotating means 30, so that the illumination optics is within the observation range of the autocollimation type measuring unit 50. In many cases, there is no light beam collected by the system. Therefore, in the approximate centering adjustment step, the light beam collected by the illumination optical system is positioned at the center of the paraxial curvature on the test surface of the test lens, and then the approximate centering is performed. First, in the substantially centering adjustment process, while rotating the lens 10 to be measured on the lens holding member 20, the rotation is performed with the measurement optical axis of the autocollimation measuring unit 50, that is, the optical axis L of the illumination optical systems 52a and 52b. The illumination optical system is moved by the horizontal movement means 56 so that the rotation axis M of the means 30 substantially coincides. Thereafter, the light beam condensed by the illumination optical system by the optical axis direction moving means 55A and 55B is obtained by the position of the paraxial curvature center on the test surface of the test lens obtained in advance from the design value (1 ob in FIG. 1). The illumination optical system is moved so as to collect light within an observation range that is position. This process completes the substantially centering adjustment.

<< Centering adjustment process >>
In the centering adjustment step, following the substantially centering adjustment step, the test lens 10 is rotated on the lens holding member 20, and the paraxial curvature center 1ob on the test surface 10b is decentered with respect to the rotation axis M in the rotating means 10. This is a step of detecting the amount and adjusting the position of the lens 10 (eccentricity adjustment) so that the amount of eccentricity becomes approximately zero. In the eccentricity adjustment here, it is not necessary to strictly match the paraxial center of curvature 1ob with the rotation axis M. However, when the eccentricity of the paraxial center of curvature of the test surface 10a is separately measured, calculation is performed in the paraxial region. Therefore, the detection accuracy is higher when the amount of eccentricity of the test surface 10b, which is the opposite surface of the test surface 10a, is smaller. A rotary encoder 40 is connected to the rotating means 10 for rotating the lens holding member. A reference for the rotation direction of the lens 10 to be measured is set based on the rotation angle value measured by the rotary encoder 40, and the center of paraxial curvature is set. Measure the direction of eccentricity.

<< Eccentricity measurement process centered on paraxial curvature >>
In the eccentric state measuring step of the paraxial curvature center, the light beam collected at the paraxial curvature center of the test surface of the test lens is detected while rotating the test lens 10, and the rotation axis of the detected light beam is detected. This is a step of measuring the eccentric amount and the eccentric direction of the paraxial curvature center with respect to the rotation axis M on the test surface of the test lens 10 from the trajectory of the swing around M and the rotation angle of the test lens 10. In the step of measuring the eccentric state of the paraxial curvature center, the illumination light from the illumination optical system is perpendicular to the tangent of the surface near the aspherical axis of the first test surface of the test lens that directly faces the illumination optical system. Irradiation to measure the eccentric state of the paraxial curvature center, and tangent to the surface of the second test surface near the aspherical axis in a state where the illumination light from the illumination optical system is transmitted through the first test surface The method includes the step of measuring the eccentric state of the paraxial curvature center by irradiating perpendicularly to the center.

<< Surface shake amount detection process >>
The surface shake amount detection step of the test surface includes the illumination optical systems 52a and 52b and the test lens so that a predetermined light beam is always irradiated onto the test surface of the test lens while rotating the test lens 10. The relative distance between the illumination optical systems 52a and 52b and the test lens 10 and the rotation angle of the test lens are detected by appropriately changing the interval with the test lens 10, and the rotation axis of the test surface is detected based on the detection result. This is a step of detecting the amount of surface deflection in the direction. In the surface shake amount detection step of the test surface, the light beam from the illumination optical system is irradiated onto the first test surface of the test lens that directly faces the illumination optical system, and the rotation axis direction of the first test surface In the state of detecting the amount of surface vibration at the surface, and in a state where the light beam from the illumination optical system is transmitted through the first test surface, the second test surface is irradiated in the direction of the rotation axis of the second test surface. This includes a step of detecting the amount of surface deflection.

<< Aspherical eccentricity calculation process >>
The aspherical eccentricity calculation step compares the surface runout amount of the test surface detected by the surface runout amount detection step of the test surface with the design data of the test surface, and the difference between the two is minimized. The relative shift amount and tilt amount with respect to the rotation axis M of the non-test lens 10 are obtained, the surface top position of the test surface with respect to the rotation axis M is calculated from the shift amount and tilt amount, and then the calculated test target From the surface top position of the surface and the amount of eccentricity and the direction of eccentricity of the paraxial curvature center of the test surface measured by the eccentric state measuring step of the paraxial curvature center of the test surface, This is a step of calculating the inclination amount and direction of the aspherical axis of the inspection surface.

[Eccentricity measuring method according to first embodiment]
The eccentricity measuring method according to the first embodiment of the present invention will be described below with reference to FIGS.
The eccentricity measuring method according to the first embodiment includes the steps described below after performing the above-described substantially centering adjustment step and centering adjustment step.

  In other words, the decentration measuring method according to the first embodiment of the present invention is configured so that the light beam from the illumination optical system is focused on the paraxial curvature center of the first test surface. Irradiate on the surface to be detected, rotate the lens to be detected, detect the trajectory around the rotation axis of the spot image formed by the reflected light from the first surface to be detected, and detect the detected spot A first paraxial curvature center decentration state measuring step of measuring an eccentric amount and an eccentric direction of the first paraxial curvature center of the first test surface with respect to the rotation axis from the locus of the image, and a light beam from the illumination optical system; (2) The first test surface of the test lens is transmitted through the first test surface so as to be focused on the paraxial curvature center of the test surface, and the second test surface is irradiated. 2 The trajectory around the rotation axis of the spot image formed by the reflected light from the surface to be detected is detected and detected. The second paraxial curvature center eccentricity measuring step for measuring the eccentric amount and the eccentric direction of the paraxial curvature center of the second test surface relative to the rotation axis from the trajectory of the spot image, while rotating the test lens, The distance between the illumination optical system and the test lens is changed as needed so that the light beam from the illumination optical system is condensed on the first test surface, and the relative relationship between the illumination optical system and the test lens is changed. A first surface shake amount detection step of detecting a movement amount and a rotation angle of the test lens, and detecting a surface shake amount in the rotation axis direction of the first test surface based on the detection result; While rotating, the interval between the illumination optical system and the test lens is changed as needed so that the light beam from the illumination optical system passes through the first test surface and is condensed on the second test surface. The relative movement of the illumination optical system and the test lens and the rotation of the test lens Detected by a second surface shake amount detecting step for detecting a corner and detecting a surface shake amount in the direction of the rotation axis of the second test surface based on the detection result, and the first surface shake amount detecting step. Further, by comparing the surface deflection amount of the first test surface with the design data of the first test surface, the relative shift amount and tilt amount with respect to the rotation axis of the test lens that minimizes the difference between the two are obtained. The first position measured by the step of measuring the eccentricity of the top surface position of the first test surface relative to the rotation axis calculated from the shift amount and the tilt amount and the first and second paraxial curvature centers. A first aspheric surface eccentricity calculating step for calculating an inclination amount and direction of the first aspherical axis with respect to the optical axis of the lens to be tested from the eccentric amount and the eccentric direction of the first and second paraxial curvature centers. And surface runout of the second test surface detected by the second surface runout amount detection step The amount of shift is compared with the design data of the second test surface to determine the relative shift amount and tilt amount with respect to the rotation axis of the non-detection lens that minimizes the difference between the two, and the shift amount and tilt amount. The first and second paraxial curvature centers measured by the step of measuring the eccentricity of the surface top position of the second test surface relative to the rotation axis calculated from the first and second paraxial curvature centers A second aspherical eccentricity calculating step for calculating an inclination amount and direction of the second aspherical axis with respect to the optical axis of the lens to be detected from the eccentricity and the eccentric direction.

  The eccentric state measuring step of the paraxial curvature center in the eccentricity measuring method according to the first embodiment is a first paraxial curvature center eccentric state measuring step of measuring the eccentric state of the paraxial curvature center of the test surface 10b. And an eccentric state measuring step of the second paraxial curvature center for measuring the eccentric state of the test surface 10a.

<< Eccentric state measurement process of paraxial curvature center of test surface 10b >>
In the step of measuring the eccentric state of the paraxial curvature center of the test surface 10b, the test lens 10 is focused on the paraxial curvature center 1ob of the test surface 10b, which is the first test surface of the test lens, while rotating the test lens 10. The collected light flux is detected, and the paraxial curvature with respect to the rotation axis M of the test surface 10b of the test lens 10 is determined from the locus of the swing around the rotation axis M of the detected light flux and the rotation angle of the test lens 10. This is a step of measuring the eccentric amount and the eccentric direction of the center 1ob.

  In this step, as shown in FIG. 3, first, the light beam collected by the illumination optical systems 52a and 52b from the illumination light source 51 is incident from a direction perpendicular to the tangent line near the aspheric axis of the test surface 10b. The illumination optical systems 52a and 52b are adjusted so that the light beam is focused on the paraxial curvature center 1ob. The light beam incident on the test surface 10b is reflected on the test surface 10b and returns on the same optical path, and a spot image is formed on the image detecting unit 54 by the imaging optical systems 53a and 53b. Here, when the test surface 10b is in an ideal state with no eccentricity (shift and tilt) with respect to the rotation axis M, the image can be obtained even if the test lens is rotated by rotating the rotation means 10. The spot image on the detection means 54 does not shake around. On the other hand, in a state where the test surface 10b is decentered with respect to the rotation axis M, when the test lens 10 is rotated, the spot image on the image detecting means 54 is the center of the paraxial curvature 1ob of the test surface 10b. Swings around according to the eccentric state. Then, an output signal of the locus of the spot image swing detected by the image detection unit 54 and an output signal related to the rotation angle of the lens to be detected detected by the rotary encoder 40 are input to the control / calculation device 70. Then, an eccentric amount (shift amount) and an eccentric direction (shift direction) of the paraxial curvature center 1ob on the test surface 10b with respect to the rotation axis M are calculated from the swing radius of the spot image and the direction from the rotation axis of the spot image. .

<< Eccentric state measurement process of paraxial curvature center of test surface 10a >>
In this step, as shown in FIG. 4, first, the illumination light condensed by the illumination optical systems 52a and 52b from the illumination light source 51 is transmitted through the test surface 10b, and then the aspheric axis on the test surface 10a. Incident from a direction perpendicular to a nearby tangent. Further, the illumination optical systems 52a and 52b are adjusted so that the light beam from the illumination optical system is condensed at the paraxial center of curvature 1oa. The light beam incident on the test surface 10a is reflected by the test surface 10a and returns on the same optical path, and a spot image is formed on the image detecting means 54 by the imaging optical systems 53a and 53b. In a state where the test surface 10a is decentered with respect to the transmission rotation axis M, when the test lens 10 is rotated, the spot image on the image detecting means 54 is decentered from the paraxial center of curvature 1oa of the test surface 10a. Swing around according to the condition. Then, an output signal of the locus of the spot image swing detected by the image detection unit 54 and an output signal related to the rotation angle of the lens to be detected detected by the rotary encoder 40 are input to the control / calculation device 70. Then, an eccentric amount (shift amount) and an eccentric direction (shift direction) of the paraxial curvature center 1oa on the test surface 10a with respect to the rotation axis M are calculated from the swing radius of the spot image and the direction from the rotation axis of the spot image. .

  The surface shake amount detecting step in the eccentricity measuring method according to the first embodiment includes the first surface shake amount detecting step for measuring the surface shake amount of the test surface 10b, and transmitting the measurement light beam through the test surface 10b. And a second surface shake amount detecting step of measuring the surface shake amount of the test surface 10a by irradiating the test surface 10a in a state where the test surface 10a is irradiated.

<< Surface shake amount detection step of the test surface 10b >>
In the surface shake amount detection step of the test surface 10b, a predetermined light beam is always irradiated onto the test surface 10b of the test lens 10 which is the first test surface of the test lens while rotating the test lens 10. In this manner, the relative distance between the illumination optical systems 52a and 52b and the test lens 10 and the rotation angle of the test lens are detected by appropriately changing the distance between the illumination optical systems 52a and 52b and the test lens 10. In this step, the surface runout amount in the direction of the rotation axis of the surface to be tested 10b is detected based on the detection result.

  In this step, first, the illumination optical systems 52a and 52b shown in FIG. 1 are measured by a horizontal moving means 56 at a predetermined measurement position (in FIG. 3, the measurement of the surface shake amount on the test surface 10b shown in FIG. The position is moved to a position Rb away from the rotation axis in the radial direction. Next, the illumination optical system 52a is moved by the optical axis direction moving means 55A or 55B so that the light beam of the illumination light source 51 is always focused on the test surface 10b at the measurement position while rotating the test lens 10. , 52b with respect to the test surface 10b is adjusted. Then, the movement amount of the optical axis direction movement means 55A or 55B is measured by a known linear direction movement amount measurement means such as a linear scale, and the output signal from the linear direction movement amount measurement means and the object detected by the rotary encoder 40 are detected. An output signal related to the rotation angle of the lens is input to the control / arithmetic unit 70. The measurement position (the position Rb away from the rotation axis in the radial direction in FIG. 3) is appropriately moved in the radial direction of the lens 10 to be measured, and the optical axis direction moving means 55A or 55B input to the control / calculation device 70. From the output signal of the movement amount and the rotation angle, the annular three-dimensional shape data of the test surface 10b is calculated. The three-dimensional shape data becomes the surface shake amount data of the test surface 10b.

<< Surface shake amount detection step of the test surface 10a >>
In this step, first, the illumination optical systems 52a and 52b are moved to a predetermined place by the optical axis direction moving means 55A or 55B and the horizontal direction moving means 56, and the luminous flux of the illumination light source 51 is detected by the test lens 10. The light is irradiated to a predetermined measurement position (a position away from the rotation axis in the radial direction in FIG. 4) that transmits the surface 10b and measures the amount of surface deflection on the surface 10a to be measured. Next, the illumination optical system 52a is moved by the optical axis direction moving means 55A or 55B so that the light beam of the illumination light source 51 is always focused on the test surface 10a at the measurement position while rotating the test lens 10. , 52b with respect to the test surface 10a is adjusted. Then, the movement amount of the optical axis direction movement means 55A or 55B is measured by a known linear direction movement amount measurement means such as a linear scale, and the output signal from the linear direction movement amount measurement means and the object detected by the rotary encoder 40 are detected. An output signal related to the rotation angle of the lens is input to the control / arithmetic unit 70. The measurement position (position in the radial direction Ra away from the rotation axis in FIG. 4) is appropriately moved in the radial direction of the lens 10 to be measured, and the optical axis direction moving means 55A or 55B input to the control / calculation device 70. From the output signal of the movement amount and the rotation angle, calculation is performed to calculate the annular three-dimensional shape data of the test surface 10a. The three-dimensional shape data becomes the surface shake amount data of the test surface 10a. When measuring the shake amount of the test surface 10a through the test surface 10b, it is preferable to calculate the surface shake amount in consideration of the refractive index of the test lens 10. The influence of the refractive index can be corrected by a known method.

  The aspheric eccentricity calculating step in the eccentricity measuring method according to the first embodiment includes a first aspheric eccentricity calculating step for measuring the aspheric eccentricity of the test surface 10b, and an aspherical surface of the test surface 10a. And a second aspheric surface eccentricity calculating step for measuring the eccentricity.

<< Aspherical eccentricity calculating step of test surface 10b >>
The aspheric eccentricity calculating step of the test surface 10b compares the surface runout amount of the test surface 10b detected by the surface shake amount detection step of the test surface 10b with the design data of the test surface 10b, The relative shift amount and tilt amount of the non-test lens 10 with the smallest difference with respect to the rotation axis M are obtained, and the surface top position of the test surface 10b with respect to the rotation axis M is calculated from the shift amount and tilt amount. Next, the surface top position of the test surface 10b was calculated, and the eccentric state measurement step of the paraxial curvature center 1oa of the test surface 10a and the eccentricity measurement step of the paraxial curvature center 1ob of the test surface 10b were measured. The aspherical surface of the test surface 10b with respect to the optical axis of the lens 10 to be tested is determined from the amount of eccentricity and the eccentric direction of the paraxial curvature center of the test surface 10a and the amount of eccentricity and the eccentric direction of the paraxial curvature center of the test surface 10b. The amount and direction of axis tilt It is a step of leaving.

Hereinafter, a process of calculating the inclination amount and direction of the aspheric axis will be described.
First, the amount of eccentricity (shift amount) and the direction of eccentricity (shift direction) of the paraxial curvature center 1ob with respect to the rotation axis M measured by the eccentric state measuring step of the paraxial curvature center of the test surface 10b, and the test surface 10a From the eccentric amount (shift amount) and the eccentric direction (shift direction) of the paraxial curvature center 1oa with respect to the rotational axis M measured by the eccentric state measuring step of the paraxial curvature center of the optical axis 1oa-1ob, the rotational axis M of the optical axis 1oa-1ob Find the slope for. Hereinafter, description will be made using an orthogonal coordinate system having the rotation axis M direction as the Z-axis direction, and X, Y, and Z axes.

  5A shows the positions of the paraxial curvature centers 1oa and 1ob and the aspherical surface top 1tb in XYZ coordinates, and FIGS. 5B and 5C show the XZ plane and YZ, respectively. It is.

  The eccentric amount (shift amount) and the eccentric direction (shift direction) of the paraxial center of curvature 1oa with respect to the rotational axis M are δa1 and θa1, respectively, and the eccentric amount (shift amount) and the eccentric direction of the paraxial curvature center 1ob with respect to the rotational axis M ( Assuming that (shift direction) is δb1 and θb1, respectively, the position of the paraxial curvature center 1oa is expressed by the following equation as shown in FIGS.

  Further, the position of the paraxial curvature center 1ob is expressed by the following equation as shown in FIGS.

  Next, the height Zo from 1 oa to 1 OB on the Z axis is calculated in consideration of the amount of eccentricity of the paraxial curvature center on both surfaces of the test lens. This height Zo is expressed by the following equation.

  From the above, the inclination of the optical axis 1oa-1ob with respect to the Z axis in the XZ plane is expressed by the following equation.

また、ＹＺ平面におけるＺ軸に対する光軸１ｏａ―１ｏｂの傾きは次式で表される。

Further, the inclination of the optical axis 1oa-1ob with respect to the Z axis in the YZ plane is expressed by the following equation.

<<< Position and Inclination of Aspherical Axis of Aspherical Surface 1b >>>
Next, the surface shake amount of the test surface 10b detected by the surface shake amount detection step of the test surface 10b is compared with the design data of the test surface 10b, and the non-test lens 10 in which the difference between the two is minimized. The relative shift amount and tilt amount with respect to the rotation axis M are obtained. This shift amount and tilt amount are the position and inclination of the aspherical axis of the aspherical surface 1b with respect to the Z axis (rotating axis). This will be specifically described below.

  First, the X surface and Y component of the position of the paraxial center of curvature 1ob on the test surface 10b obtained by the equations (3) and (4) are detected surface 10b detected by the surface deflection amount detection step. Are shifted in the X direction and the Y direction, respectively. Next, the surface shake amount data of the test surface 10b is set in the Z-axis direction so that the difference between the surface shake amount data of the test surface 10b detected by the surface shake amount detection step and the design data is minimized. Shift. Further, the surface runout amount data of the test surface 10b is tilted so that the difference from the design data of the test surface 10b is minimized with the paraxial curvature center 1ob of the test surface 10b as the center. The difference between the surface runout amount data of the test surface 10b and the design data is the smallest. FIG. 5 shows the tilt amount of the surface shake amount data of the test surface 10b obtained as described above as the tilt εbx1 with respect to the Z axis on the XZ plane and the tilt with respect to the Z axis on the YZ plane as εby1. It is.

  The tilt amount obtained in this way is the inclination of the aspherical axis 1Axb of the test surface 10b with respect to the Z axis.

  Next, based on the position of the paraxial center of curvature 1ob (1obx, 1oby) and the inclination (εbx1, εby1) of the aspherical axis 1Axb with respect to the Z axis, the position of the surface apex 1tb of the test surface 10b with respect to the Z axis is calculated. To do. As shown in FIGS. 5B and 5C, the position of the top 1tb (1tbx, 1tby) of the test surface 10b is expressed by the following equation.

  Next, the position of the surface top 1tb (1tbx, 1tby) of the test surface 10b obtained by the above equations (8) and (9), and the paraxial curvature calculated in the eccentric state measuring step of the paraxial curvature center. Based on the shift amount δb1 and shift direction θb1 of the center 1ob with respect to the rotation axis M, and the shift amount δa1 and shift direction θa1 of the center axis 1oa with respect to the rotation axis M, the paraxial curvature center 1oa shown in FIG. A projected length 1Zb on the Z axis between the surface top position 1tb is calculated. Here, 1Zb is expressed by the following equation.

  From the above, the inclination of the optical axis 1oa-1ob with respect to the Z axis in the XZ plane is expressed by the following equation.

また、ＸＺ平面におけるＺ軸に対する非球面軸１Ａｘｂの傾きは次式で表される。

The inclination of the aspherical axis 1Axb with respect to the Z axis in the XZ plane is expressed by the following equation.

  Next, the X component εbx of the aspherical axis eccentricity is calculated from the aspherical axis rbx with respect to the Z axis on the XZ plane and the inclination of the optical axis 1oa-1ob. As shown in FIG. 5B, the X component εbx is expressed by the following equation.

  Next, the distance Lbx of the line segment when a perpendicular is drawn from the X component 1tbx at the surface top position 1tb to the X component 1oax-1obx of the optical axis 1oa-1ob shown in FIG. In order to obtain Lbx, first, a projection length 1rbx obtained by projecting the aspherical axis 1Axb onto the XZ plane is obtained. 1 rbx is expressed by the following equation.

  By using the equation (14), Lbx is expressed by the following equation.

  Similarly, the inclination of the optical axis 1oa-1ob with respect to the Z axis in the YZ plane is expressed by the following equation.

また、ＹＺ平面におけるＺ軸に対する非球面軸１Ａｘｂの傾きは次式で表される。

The inclination of the aspherical axis 1Axb with respect to the Z axis in the YZ plane is expressed by the following equation.

  Next, the Y component εby of the aspherical axis eccentricity is calculated from the aspherical axis rby with respect to the Z axis on the YZ plane and the inclination of the optical axis 1oa-1ob. As shown in FIG. 5C, the Y component εby is expressed by the following equation.

  Next, as shown in FIG. 5C, a distance Lby of a line segment when a perpendicular is drawn from the Y component 1tby at the surface top position 1tb to the Y component 1oa-1by of the optical axis 1oa-1ob is obtained. In order to obtain Lby, first, a projection length 1rby obtained by projecting the aspherical axis 1Ayb onto the YZ plane is obtained. 1rby is expressed by the following equation.

  By using the equation (19), Lby is expressed by the following equation.

  Next, the distance from the optical axis 1oa-1ob to the top of the aspheric surface is obtained from Lbx and Lby calculated by the above equations (15) and (20), and the inclination of the aspherical axis 1Axb with respect to the optical axis 1oa-1ob, That is, an aspheric eccentricity εb is obtained. The aspheric eccentricity εb is expressed by the following equation.

  The aspheric eccentricity can be obtained as a tilt by the equation (21). Furthermore, the aspheric eccentricity can be obtained as a shift δb by the following equation.

  Next, the eccentric direction θb of the aspherical axis 1Axb with respect to the optical axis 1oa-1ob is calculated. θb is expressed by the following equation because the aspherical surface top 1tb is separated by Lbx in the X direction and Lby in the Y direction with respect to the optical axis 1oa-1ob.

  Through the above steps, the inclination εb (aspheric eccentricity) of the aspherical axis 1Axb with respect to the optical axis 1oa-1ob and the eccentric direction θb of the aspherical axis 1Axb with respect to the optical axis 1oa-1ob can be accurately obtained.

<<< Position and Inclination of Aspherical Axis of Aspherical Surface 1a >>>
Next, the surface shake amount of the test surface 10a detected by the surface shake amount detection step of the test surface 10a is compared with the design data of the test surface 10a, and the non-test lens 10 in which the difference between the two is minimized. The relative shift amount and tilt amount with respect to the rotation axis M are obtained. The shift amount and the tilt amount are the position and inclination of the aspherical axis of the aspherical surface 1a with respect to the Z axis (rotating axis). This will be specifically described below.

  First, the X- and Y-components of the position of the paraxial center of curvature 1oa on the test surface 10a obtained by the equations (1) and (2) are detected surface 10a detected by the surface deflection amount detection step. Are shifted in the X direction and the Y direction, respectively. Next, the surface runout amount data of the test surface 10a is set in the Z-axis direction so that the difference between the surface runout amount data of the test surface 10a detected by the surface runout amount detection step and the design data is minimized. Shift. Further, the surface runout amount data of the test surface 10a is tilted around the paraxial curvature center 1oa of the test surface 10a so that the difference from the design data of the test surface 10a is minimized. The difference between the surface runout amount data of the test surface 10a and the design data is the smallest. FIG. 6 shows the tilt amount of the surface shake amount data of the test surface 10a obtained in this way as the tilt εax1 with respect to the Z axis on the XZ plane and the tilt with respect to the Z axis on the YZ plane as εay1. It is.

  The amount of tilt obtained in this way is the inclination of the aspherical axis 1Axa of the test surface 10a with respect to the Z axis.

  Next, based on the position of the paraxial curvature center 1oa (1oax, 1oay) and the inclination (εax1, εay1) of the aspherical axis 1Axa with respect to the Z axis, the position of the surface apex 1ta of the test surface 10a with respect to the Z axis is calculated. To do. As shown in FIGS. 6B and 6C, the position of the surface top 1ta (1tax, 1tay) of the test surface 10a is expressed by the following equation.

  Next, the position of the surface top 1ta (1tax, 1tay) of the test surface 10a obtained by the above equations (24) and (25), and the paraxial curvature calculated in the eccentric state measuring step of the paraxial curvature center. Based on the shift amount δb1 and shift direction θb1 of the center 1ob with respect to the rotation axis M, and the shift amount δa1 and shift direction θa1 of the center axis 1oa with respect to the rotation axis M, the paraxial curvature center 1oa shown in FIG. A projected length 1Za on the Z axis between the surface top position 1ta is calculated. Here, 1Za is represented by the following equation.

  From the above, the inclination of the aspherical axis 1Axa with respect to the Z axis in the XZ plane is expressed by the following equation.

  Next, the X component εax of the aspherical axis eccentricity is calculated from the aspherical axis rax with respect to the Z axis in the XZ plane and the inclination of the optical axis 1oa-1ob. As shown in FIG. 6B, the X component εax is expressed by the following equation.

  Next, as shown in FIG. 6B, a distance Lax of a line segment when a perpendicular is drawn from the X component 1tax at the surface top position 1ta to the X component 1oax-1obx of the optical axis 1oa-1ob is obtained. In order to obtain Lax, first, a projection length 1 ray obtained by projecting the aspheric axis 1Axa onto the YZ plane is obtained. 1 ray is expressed by the following equation.

  By using the equation (29), Lax is expressed by the following equation.

  The inclination of the aspherical axis 1Axa with respect to the Z axis in the YZ plane is expressed by the following equation.

  Next, the Y component εay of the aspherical axis eccentricity is calculated from the aspherical axis ray with respect to the Z axis on the YZ plane and the inclination of the optical axis 1oa-1ob. As shown in FIG. 6C, the Y component εay is expressed by the following equation.

  Next, as shown in FIG. 6C, the distance Ray of the line segment when a perpendicular is drawn from the Y component 1tay at the surface top position 1ta to the Y component 1oay-1ob of the optical axis 1oa-1ob is obtained. In order to obtain Lay, first, a projection length 1 ray obtained by projecting the aspherical axis 1Aya onto the YZ plane is obtained. 1 ray is expressed by the following equation.

  By using the equation (33), Lay is expressed by the following equation.

  Next, the distance from the optical axis 1oa-1ob to the top of the aspheric surface is obtained by Lax and Ray calculated by the above equations (15) and (20), and the inclination of the aspherical axis 1Axa with respect to the optical axis 1oa-1ob, That is, an aspheric eccentricity εa is obtained. The aspheric eccentricity εa is expressed by the following equation.

  The aspheric decentering amount can be obtained as a tilt by the equation (35). Furthermore, the aspheric eccentricity can be obtained as the shift δa by the following equation.

  Next, the eccentric direction θa of the aspherical axis 1Axa with respect to the optical axis 1oa-1ob is calculated. θa is expressed by the following equation because the aspherical surface apex 1ta is separated by Lax in the X direction and by Lay in the Y direction with respect to the optical axis 1oa-1ob.

  Through the above steps, the inclination εa (aspheric eccentricity) of the aspherical axis 1Axa relative to the optical axis 1oa-1ob and the eccentric direction θa of the aspherical axis 1Axa relative to the optical axis 1oa-1ob can be accurately obtained.

  According to the eccentricity measuring method according to the first embodiment, the lens 53b constituting the illumination optical system of the auto-collimation measuring unit 50 is moved when measuring the shake amount of the surface to be measured. In addition, the drive unit can be miniaturized, and the position of the condensed light beam can be accurately followed on the test surface even if the test lens is rotated at high speed. As a result, the measurement time can be shortened.

[Eccentricity measuring method according to second embodiment]
Hereinafter, the eccentricity measuring method according to the second embodiment of the present invention will be described.

In the decentering measurement method according to the second embodiment of the present invention, the first test of the test lens is performed so that the light beam from the illumination optical system is condensed at the paraxial curvature center of the first test surface. Irradiates the surface, rotates the lens to be detected, detects the locus of the swing around the rotation axis of the spot image formed by the reflected light from the first surface to be detected, and detects the detected spot image A first paraxial curvature center decentration state measuring step for measuring an eccentricity amount and an eccentric direction of the first paraxial curvature center of the first test surface with respect to the rotation axis from the trajectory, and a light beam from the illumination optical system as a second The first test surface of the test lens is transmitted through the first test surface so as to be focused on the paraxial curvature center of the test surface and irradiated onto the second test surface, and the test lens is rotated to rotate the second test surface. Detects the trajectory around the rotation axis of the spot image formed by the reflected light from the surface to be detected. A second paraxial curvature center decentration state measuring step for measuring an eccentric amount and an eccentric direction of the paraxial curvature center of the second test surface with respect to the rotation axis from the locus of the spot image, while rotating the test lens, The distance between the illumination optical system and the test lens is changed as needed so that the light beam from the illumination optical system is collected on the first test surface, and the relative movement of the illumination optical system and the test lens is changed. A first surface shake amount detecting step for detecting a surface shake amount in the direction of the rotation axis of the first test surface based on the detection result; A step of measuring the eccentric state at the center of axial curvature, the step of measuring the eccentric state at the center of the second paraxial curvature, and the step of detecting the amount of first surface shake, and a step of inverting the lens to be tested;
The second test of the test lens is such that the light beam from the illumination optical system is focused on the paraxial curvature center of the second test surface of the test lens that has been inverted by the step of inverting the test lens. Irradiates the surface, rotates the lens to be detected, detects the locus of the swing around the rotation axis of the spot image formed by the reflected light from the second surface to be detected, and detects the detected spot image A third paraxial curvature center decentration state measuring step for measuring the decentering amount and decentering direction of the paraxial curvature center of the second test surface with respect to the rotation axis from the trajectory, and a light beam from the illumination optical system as a first The first test surface is transmitted through the second test surface of the test lens so that the light is focused on the paraxial curvature center of the test surface, and the test lens is rotated to rotate the first test surface. The trajectory around the rotation axis of the spot image formed by the reflected light from the test surface is detected. And a fourth paraxial curvature center eccentricity measuring step for measuring a decentering amount and a decentering direction of the paraxial curvature center of the first test surface with respect to the rotation axis from the locus of the detected spot image, and a test lens. While rotating, the distance between the illumination optical system and the test lens is changed as needed so that the light beam from the illumination optical system is condensed on the second test surface, and the illumination optical system and the test lens are also changed. Detecting a relative movement amount and a rotation angle of the test lens, and detecting a surface shake amount in the rotation axis direction of the second test surface based on the detection result; The surface runout amount of the first test surface detected by the first surface runout amount detection step is compared with the design data of the first test surface, and the relative difference with respect to the rotation axis is the smallest difference between the two. A shift amount and a tilt amount, and a shift amount and a tilt amount. The first and second paraxial curvature centers measured by the eccentric state measuring step of the first test surface relative to the rotation axis calculated from the above and the first and second paraxial curvature centers A first aspheric surface decentration amount calculating step for calculating an inclination amount and a direction of the first aspheric surface axis with respect to the optical axis of the lens to be detected, and the second surface shake amount detection By comparing the surface runout amount of the second test surface detected by the process with the design data of the second test surface, the relative shift amount and tilt amount with respect to the rotation axis with the smallest difference between them are obtained. And determining the surface top position of the second test surface relative to the rotation axis calculated from the shift amount and the tilt amount, and the third and fourth paraxial curvature centers measured in the eccentric state measuring step. From the amount of eccentricity and the direction of eccentricity of the first and second paraxial curvature centers, And a second aspheric surface eccentricity calculating step for calculating an inclination amount and direction of the second aspheric axis with respect to the optical axis of the lens.

  That is, in the eccentricity measuring method according to the second embodiment, after performing the above-described approximate centering adjustment process and centering adjustment process in a state where the test surface 10b of the test lens faces the illumination optical system. The first paraxial curvature center eccentricity measuring step for measuring the eccentric state of the paraxial curvature center 1ob of the test surface 10b, and the illumination light from the illumination optical system is transmitted through the test surface 10b and the test surface A second paraxial curvature center measuring step for measuring the eccentric state of the paraxial curvature center 1 oa of the test surface 10 a by irradiating on the test surface 10 a, and a first detecting method for detecting the surface deflection amount of the test surface 10 b. Similarly, in the state where the surface shake amount detecting step, the step of inverting the test lens, and the test surface 10a side of the test lens face the illumination optical system, the substantially centering adjustment step and the centering adjustment step are performed. After performing, the 3rd which measures the eccentric state of the paraxial curvature center of the to-be-tested surface 10a Measuring the eccentric state of the paraxial curvature center of the test surface 10b by transmitting the illumination light from the illumination optical system through the test surface 10a and irradiating the test surface 10b with the illumination light from the paraxial curvature center The fourth paraxial curvature center eccentricity measuring step and the second surface shake amount detecting step for detecting the surface shake amount of the test surface 10a are provided.

Here, the step of obtaining the inclination of the aspherical axis with respect to the optical axis 1oa-1ob (aspherical eccentricity) and the eccentric direction of the aspherical axis with respect to the optical axis 1oa-1ob shown in FIG. Since it is the same as the eccentricity measuring method according to the embodiment, the description is omitted.
According to the eccentricity measuring method according to the second embodiment, since the measurement light flux is not measured in the state of being transmitted through the surface to be measured in the surface shake amount detection step, the shape error of the surface through which the measurement light velocity is transmitted. It is possible to measure the amount of runout of the surface to be measured with high accuracy without being affected by the above.

FIG. 1 is a schematic configuration explanatory diagram of an eccentricity measuring apparatus according to the present invention. FIG. 2 is a schematic configuration explanatory diagram of the eccentricity measuring apparatus of the present invention. FIG. 3 is a diagram illustrating a measurement state of the first test surface. FIG. 4 is a diagram illustrating a measurement state of the second test surface. FIGS. 5A, 5B, and 5C are views showing the concept for obtaining the aspheric eccentricity value of the first test surface. FIGS. 6A, 6B, and 6C are views showing the concept for obtaining the aspheric eccentricity value of the second test surface. FIG. 7 is a schematic configuration explanatory diagram of an eccentricity measuring apparatus according to a modification of the present invention. FIG. 8 is a schematic configuration explanatory diagram of an eccentricity measuring apparatus according to a modification of the present invention. FIG. 9 is a diagram showing the deviation between the aspheric axis of the aspheric lens and the optical axis. FIG. 10 is a schematic configuration diagram showing a conventional aspheric lens decentration measuring apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Test lens 20 ... Lens holding member 30 ... Rotating means 51 ... Illumination light source 52a, 52b ... Illumination optical system 53a, 53b ... Imaging optical system 54 ... Image detection means 55 ... Optical axis direction moving means 56 ... Horizontal direction movement Means 70 ... Control / arithmetic unit (eccentric state detecting unit, surface deflection amount detecting unit, aspherical eccentricity calculating unit)

Claims (4)

An aspheric lens eccentricity measuring device,
A lens holding member for holding the test lens;
Rotating means for rotating the holding member;
An illumination light source;
An illumination optical system for irradiating the test surface of the test lens with light from the illumination light source;
An imaging optical system that forms an image of reflected light from the test surface of the test lens;
Image detecting means for detecting an image formed by the imaging optical system;
An optical axis direction moving means capable of moving a relative position in the optical axis direction of the illumination optical system with respect to the lens holding member;
A light flux from the illumination optical system collected at the center of the paraxial curvature of the test surface of the test lens is detected by the image detecting means, and the detected light flux swings around the rotation axis of the rotating means. An eccentric state calculation unit that calculates an eccentric amount and an eccentric direction of the paraxial curvature center with respect to the rotation axis from the locus of
The distance between the illumination optical system and the lens holding member is changed at any time by the optical axis direction moving means so that the light beam from the illumination optical system is condensed on the test surface of the test lens, and the illumination A surface shake amount detection unit that detects a relative movement amount of the optical system and the lens holding member and a rotation angle of the rotation unit, and detects a surface shake amount in the direction of the rotation axis of the test surface based on the detection result; ,
The aspherical surface with respect to the optical axis of the lens to be tested is calculated based on the surface shake amount of the test surface detected by the surface shake amount detection unit and the eccentric amount and the eccentric direction of the paraxial curvature center calculated by the eccentric state calculation unit. An aspherical lens eccentricity measuring device comprising an aspherical eccentricity calculating means for calculating an axis inclination amount and direction. The illumination light from the illumination optical system is irradiated onto the test surface of the test lens, the reflected light from the test surface is detected, and the inclination amount and direction of the aspherical axis with respect to the optical axis of the test lens are determined. A method for measuring the eccentricity of an aspheric lens to be measured,
The light beam from the illumination optical system is irradiated onto the test surface of the test lens so as to be focused on the paraxial curvature center of the test surface, and the test lens is rotated to The paraxial curvature is detected by detecting the trajectory around the rotation axis of the spot image formed by the reflected light, and measuring the eccentric amount and the eccentric direction of the paraxial curvature center with respect to the rotation axis from the detected spot image trajectory A process for measuring the eccentricity of the center,
While rotating the test lens, the distance between the illumination optical system and the test lens is changed as needed so that the light beam from the illumination optical system is collected on the test surface, and the illumination optical system and the test lens are also changed. A surface shake amount detection step of detecting a relative movement amount of the test lens and a rotation angle of the test lens, and detecting a surface shake amount in the rotation axis direction of the test surface based on the detection result;
The surface runout amount of the test surface detected by the surface runout amount detection step is compared with the design data of the test surface, and the relative shift amount and tilt amount with respect to the rotation axis with the smallest difference between them are obtained. And determining the surface top position of the test surface relative to the rotation axis calculated from the shift amount and the tilt amount, and the eccentric amount and the eccentric direction of the paraxial curvature center measured by the eccentric state measuring step. An aspherical lens eccentricity measuring method, comprising: an aspherical eccentricity calculating step for calculating an inclination amount and direction of an aspherical axis with respect to the optical axis of the test lens. The illumination light from the illumination optical system is irradiated onto the test surface of the test lens, the reflected light from the test surface is detected, and the inclination amount and direction of the aspherical axis with respect to the optical axis of the test lens are determined. A method for measuring the eccentricity of an aspheric lens to be measured,
The light beam from the illumination optical system is irradiated onto the first test surface of the test lens so as to be focused on the center of the paraxial curvature of the first test surface, and the test lens is rotated to rotate the first test surface. A trajectory around the rotation axis of the spot image formed by reflected light from one test surface is detected, and the center of the paraxial curvature of the first test surface with respect to the rotation axis is detected from the detected spot image trajectory. An eccentric state measuring step of a first paraxial curvature center for measuring an eccentric amount and an eccentric direction;
While irradiating the light beam from the illumination optical system on the second test surface through the first test surface of the test lens so that the light beam from the illumination optical system is focused on the paraxial curvature center of the second test surface, By rotating the lens to be detected, a trajectory around the rotation axis of the spot image formed by the reflected light from the second surface to be detected is detected, and from the detected spot image trajectory, the second with respect to the rotation axis is detected. A second paraxial curvature center eccentricity measuring step for measuring an eccentric amount and an eccentric direction of the paraxial curvature center of the test surface;
While rotating the test lens, the distance between the illumination optical system and the test lens is changed as needed so that the light beam from the illumination optical system is condensed on the first test surface, and the illumination optical system And a relative movement amount of the test lens and a rotation angle of the test lens, and a first surface shake amount for detecting a surface shake amount in the rotation axis direction of the first test surface based on the detection result. A detection process;
While rotating the test lens, the distance between the illumination optical system and the test lens is set so that the light beam from the illumination optical system passes through the first test surface and is condensed on the second test surface. While changing as needed, the relative movement amount of the illumination optical system and the test lens and the rotation angle of the test lens are detected, and the surface shake amount in the direction of the rotation axis of the second test surface based on the detection result A second surface shake amount detecting step for detecting
By comparing the surface run-out amount of the first test surface detected by the first surface run-out amount detection step with the design data of the first test surface, the non-test lens of which the difference between the two is minimized The relative shift amount and tilt amount with respect to the rotation axis are obtained, the top position of the first test surface with respect to the rotation axis calculated from the shift amount and tilt amount, and the first and second paraxial curvatures. From the decentering amount and decentering direction of the first and second paraxial curvature centers measured in the center decentering state measurement step, the tilt amount and direction of the first aspherical axis with respect to the optical axis of the lens to be measured A first aspheric surface eccentricity calculating step for calculating
The non-detecting lens in which the surface shake amount of the second test surface detected in the second surface shake amount detection step is compared with the design data of the second test surface, and the difference between the two is minimized. And calculating the relative shift amount and tilt amount with respect to the rotation axis, the top position of the second test surface relative to the rotation axis calculated from the shift amount and tilt amount, and the first and second paraxial axes From the amount of decentering and the direction of decentering of the first and second paraxial curvature centers measured in the step of measuring the center of curvature, the amount and direction of inclination of the second aspherical axis with respect to the optical axis of the lens to be examined. And a second aspheric decentration amount calculating step for calculating a decentering amount of the aspheric lens. The illumination light from the illumination optical system is irradiated onto the test surface of the test lens, the reflected light from the test surface is detected, and the inclination amount and direction of the aspherical axis with respect to the optical axis of the test lens are determined. A method for measuring the eccentricity of an aspheric lens to be measured,
The light beam from the illumination optical system is irradiated onto the first test surface of the test lens so as to be focused on the center of the paraxial curvature of the first test surface, and the test lens is rotated, A trajectory around the rotation axis of the spot image formed by the reflected light from the first test surface is detected, and the paraxial curvature center of the first test surface with respect to the rotation axis is detected from the detected spot image trajectory. An eccentric state measuring step of a first paraxial curvature center for measuring an eccentric amount and an eccentric direction of
While irradiating the light beam from the illumination optical system on the second test surface through the first test surface of the test lens so that the light beam from the illumination optical system is focused on the paraxial curvature center of the second test surface, By rotating the lens to be detected, a trajectory around the rotation axis of the spot image formed by the reflected light from the second surface to be detected is detected, and from the detected spot image trajectory, the second with respect to the rotation axis is detected. A second paraxial curvature center eccentricity measuring step for measuring an eccentric amount and an eccentric direction of the paraxial curvature center of the test surface;
While rotating the test lens, the distance between the illumination optical system and the test lens is changed as needed so that the light beam from the illumination optical system is condensed on the first test surface, and the illumination optical system And a relative movement amount of the test lens and a rotation angle of the test lens, and a first surface shake amount for detecting a surface shake amount in the rotation axis direction of the first test surface based on the detection result. A detection process;
A step of inverting the lens after the first paraxial curvature center eccentricity measuring step, the second paraxial curvature center eccentricity measuring step, and the first surface deflection amount detecting step;
The second test of the test lens is such that the light beam from the illumination optical system is focused on the paraxial curvature center of the second test surface of the test lens that has been inverted by the step of inverting the test lens. Irradiates the surface, rotates the lens to be detected, detects the locus of the swing around the rotation axis of the spot image formed by the reflected light from the second surface to be detected, and detects the detected spot image A third paraxial curvature center eccentric state measuring step for measuring an eccentric amount and an eccentric direction of the paraxial curvature center of the second test surface with respect to the rotation axis from the locus of
While irradiating the light beam from the illumination optical system on the first test surface through the second test surface of the test lens so that the light beam from the illumination optical system is focused on the paraxial curvature center of the first test surface, By rotating the lens to be detected, a locus of swinging around the rotation axis of the spot image formed by the reflected light from the first surface to be detected is detected, and a first locus with respect to the rotation axis is detected from the locus of the detected spot image. A fourth paraxial curvature center eccentricity measuring step for measuring an eccentric amount and an eccentric direction of the paraxial curvature center of one test surface;
While rotating the test lens, the interval between the illumination optical system and the test lens is changed as needed so that the light beam from the illumination optical system is condensed on the second test surface, and the illumination optical system And a relative movement amount of the test lens and a rotation angle of the test lens, and a second surface shake amount for detecting a surface shake amount in the rotation axis direction of the second test surface based on the detection result. A detection process;
The surface runout amount of the first test surface detected by the first surface runout amount detection step is compared with the design data of the first test surface, and the relative difference with respect to the rotation axis is the smallest difference between the two. A shift amount and a tilt amount, and a top position of the first test surface with respect to the rotation axis calculated from the shift amount and the tilt amount, and an eccentric state of the first and second paraxial curvature centers. A first amount of inclination and direction of the first aspherical axis with respect to the optical axis of the lens to be measured is calculated from the amount of eccentricity and the direction of eccentricity of the first and second paraxial curvature centers measured in the measuring step. An aspheric eccentricity calculating step of
The surface runout amount of the second test surface detected by the second runout amount detection step is compared with the design data of the second test surface, and the relative difference with respect to the rotation axis is the smallest difference between the two. A shift amount and a tilt amount, and a top position of the second test surface with respect to the rotation axis calculated from the shift amount and the tilt amount, and an eccentric state of the third and fourth paraxial curvature centers A second amount for calculating the inclination amount and direction of the second aspherical axis with respect to the optical axis of the lens to be measured from the eccentric amount and the eccentric direction of the first and second paraxial curvature centers measured in the measuring step. A method for measuring the eccentricity of an aspherical lens.

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