JP2005156260A - Centering method, centering mechanism, and apparatus for measuring aspherical surface eccentricity provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centering mechanism capable of accurately performing centering, regardless of the shape of the lens to be inspected. <P>SOLUTION: The centering mechanism is provided with a holding unit (a lens holder 2) for holding a double-aspherical lens 1 to be inspected; a rotating unit (an air spindle 3 and a motor 4) for rotating the holding unit; a measurement unit (a rotary encoder 5), arranged on the axis of rotation of the rotating unit; and a centering unit, arranged in a direction intersecting with the axis of rotation at right angles and provided with both a contact member (a centering member 6) to be in contact with the double-aspherical lens 1 and a moving member (a centering member moving table 7) for moving the contact member. The moving member (the centering member moving table 7) is provided with a moving mechanism for moving the contact member, in a first direction along the axis of rotation and in the second direction which intersects with the first direction at right angles. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a centering method, a centering mechanism, and an aspherical eccentricity measuring apparatus including the centering mechanism.

  In the case of a single-sided aspherical lens whose one surface is an aspherical surface, the optical axis connects the center of curvature of the spherical surface and the center of curvature of the aspherical surface (the center of curvature of the portion that can be regarded as a sphere near the symmetry axis of the aspherical surface). Is the axis. The aspheric axis is an axis connecting the paraxial center of curvature and the top of the aspheric surface. On the other hand, in the case of a lens in which both surfaces are aspherical surfaces, the optical axis is an axis connecting the paraxial curvature centers. The aspheric axis is an axis connecting the paraxial center of curvature and the aspheric surface apex.

  If the lens is manufactured as designed, when one side is aspherical, the optical axis and aspherical axis are completely coincident. When both surfaces are aspheric, each of the two aspheric axes coincides with the optical axis.

  In practice, however, it is difficult to manufacture such a lens. For this reason, a slight deviation occurs between the optical axis and the aspherical axis. If this deviation is defined as an aspherical eccentricity, the aspherical eccentricity can be expressed by a tilt (tilt) of the optical axis with respect to the aspherical axis and a distance (shift) from the optical axis to the top of the aspherical surface. Therefore, when an aspherical lens is manufactured, it is important to measure the amount of aspherical eccentricity of the completed lens.

  In order to meet such demands, several aspheric lens decentration measuring apparatuses have been proposed. For example, Japanese Patent Laid-Open No. 6-258182 discloses an aspherical lens eccentricity measuring apparatus as shown in FIG. Here, a test lens having only one aspheric surface is measured as the test object 101.

  In this apparatus, the measurement of the aspheric eccentricity is performed according to the following procedure. First, the test object 101 is rotated around a rotation axis that substantially matches the optical axis. In this state, the test object 101 is irradiated with light from the direction of the rotation axis. The irradiated light is reflected by the test object 101. Therefore, the reflected light is imaged as a spot image on the imaging surface of the optical system. Here, since the test object 101 is rotating, the spot image also moves to draw a circle. A deviation between the optical axis and the rotation axis is detected from the size of the circle drawn by the spot image. Here, a reference position is set on the outer periphery of the test object 101, and a line (reference line) connecting the reference position and the rotation center of the test object 101 is set. The direction of spot deviation is determined from the angle formed by the reference line and the line connecting the spot image and the rotation center of the test object 101.

  Subsequently, the deflection of the surface of the aspheric surface in the optical axis direction accompanying the rotation of the test object 101 is measured. Then, the blur correction value is calculated from the size and direction of the circle. Then, the inclination between the optical axis and the aspherical axis is obtained by subtracting the correction value from the measured shake.

  In the above apparatus, an actuator 114 is arranged. The actuator 114 is used to apply an external force to the test object 101 in a direction substantially perpendicular to the optical axis. The angle sensor 104 and the spot position detection means 108 are for calculating the setting deviation α [minute] and the direction β [degree] of the test object 101. The driving means 103 is for rotating the test object 101. The vertical displacement measuring means 115 is for measuring the vertical displacement of the test object 101. The computing means 110 is configured by a computer or the like and is a part that performs various controls.

  FIG. 18 is a conceptual diagram showing the relationship among the test object 101, the imaging plane 108 a of the spot position detection means 108, the optical axis 111 of the test object 101, the spindle rotation axis 112, and the aspherical axis 113. In FIG. 18, the intersection of the rotation axis 112 and the imaging plane 108a is O, and the intersection of the optical axis 111 and the imaging plane 108a is P. Also, let Q be the intersection of the aspherical axis 113 and the image plane 108a. Further, x and y axes orthogonal to the image plane 108a are taken as shown in the figure. An angle α formed by the optical axis 111 and the spindle rotation axis 112 indicates the magnitude of an error due to setting deviation, and an angle β formed by the line segment OP and the x axis indicates the magnitude of the error.

The calculation means 110 calculates the setting deviation in the direction perpendicular to the optical axis from the value of α, issues an instruction to the drive means 103 according to these, and until the angle sensor 104 detects that the rotation angle is β. The test object 101 is rotated. Next, the object 101 is moved in the direction perpendicular to the optical axis by a specified amount from the position of the rotation angle β by a feedback system including the actuator 114 and the vertical displacement measuring means 105.
JP-A-6-258182

  Japanese Patent Laid-Open No. 6-258182 discloses that the actuator 114 is moved in a direction perpendicular to the optical axis based on α [minute], but the relationship between α and the moving amount (centering adjustment amount) is not shown. . Therefore, it is considered that proper centering cannot be performed unless the centering adjustment amount can be obtained from α.

  When the lens surface of the test object 101 is in contact with the holder that holds the test object 101 and the normal angle of the lens surface at the contact portion is greater than 45 degrees with respect to the rotation axis, Even if the 101 is pushed in the direction perpendicular to the optical axis, the test object 101 does not move smoothly in the direction perpendicular to the optical axis. This makes it difficult to adjust the aspherical paraxial curvature center to the rotation axis.

  Further, the test object 101 is limited to a single-side aspheric lens, and has a structure that supports the test object 101 on the spherical surface side. According to the aspherical lens decentration measuring apparatus shown in the background art, it seems possible to perform measurement even if the test object 101 is a double-sided aspherical lens. In this case, when measuring a double-sided aspheric lens, the test object is supported by the aspherical surface. Here, the apparatus of the background art obtains the aspheric eccentricity on the assumption that the spherical center on the spherical surface exists on the rotation axis. However, since the center of the paraxial curvature of the supported surface does not necessarily exist on the rotation axis, the detection accuracy of the aspherical eccentricity is lowered.

  The present invention has been made paying attention to such a problem, and a centering method, a centering mechanism, and an aspherical eccentric provided with the centering method capable of accurately centering regardless of the shape of the test object. It is to provide a measuring device.

  In order to achieve the above object, a first invention is a centering mechanism, which is a holding unit that holds a test object, a rotating unit that rotates the holding unit, and a rotating shaft of the rotating unit. A measuring unit disposed; a contact member that contacts the test object; a moving member that moves the contact member; and a centering unit that is disposed in a direction perpendicular to the rotation axis. The moving member includes a moving mechanism that moves the contact member in a first direction along the rotation axis and in a second direction orthogonal to the first direction.

  According to a second aspect of the present invention, in the centering mechanism according to the first aspect, the contact member includes a spherical surface portion formed in the first direction and a flat surface portion formed in the second direction. Have.

  According to a third aspect of the present invention, in the centering mechanism according to the first aspect, the moving mechanism includes a moving means for moving the contact member in the first direction, and the contact member in the second direction. A moving means for moving is provided.

  According to a fourth aspect of the present invention, in the centering mechanism according to the first aspect, the contact member includes a tip member, a main body portion for supporting the tip member, and the tip member and the main body portion connected to each other. The tip member includes a first element having a spherical portion formed in the first direction, a second element having a planar portion formed in the second direction, and the first member. A sensor provided between the first element and the second element for detecting contact with the test object;

  According to a fifth aspect of the present invention, in the centering mechanism according to the first aspect, the contact member includes a tip portion, a body portion for supporting the tip portion, and the tip portion and the body portion connected to each other. And a sensor for detecting contact of the contact member with the test object.

  According to a sixth aspect of the present invention, in the centering mechanism according to the first aspect, the contact member includes a tip portion, and the direction of the portion where the tip portion abuts on the test object can be set in any direction. is there.

  According to a seventh aspect of the invention, in the centering mechanism according to the sixth aspect of the invention, the contact member includes a tip portion, and the tip portion is provided with a sensor that detects contact with the test object.

  According to an eighth aspect of the present invention, in the centering mechanism according to the first or seventh aspect, the contact member includes a tip portion, a body portion for supporting the tip portion, the tip portion, and the body portion. And the tip has an arc larger than the outer diameter of the test object formed in the second direction.

  According to a ninth invention, in the centering mechanism according to any one of the first to eighth inventions, the contact member includes a tip portion, a main body portion for supporting the tip portion, and the tip portion. And a connecting portion that connects the main body portion, and the tip portion has a conical portion formed in the first direction.

  A tenth aspect of the invention is an aspheric surface eccentricity measuring apparatus comprising the centering mechanism according to any one of the first to ninth aspects.

  According to an eleventh aspect of the present invention, in the aspheric eccentricity measuring apparatus according to the tenth aspect of the invention, the aspherical eccentricity measuring apparatus has a sensor for measuring a shake amount of both surfaces of the test object.

  A twelfth aspect of the invention is a centering method for performing centering using the centering mechanism according to any one of the first to ninth aspects, wherein the measuring unit is rotated while rotating the test object. In the first step of measuring by the above, the second step of calculating the position of the paraxial curvature center of one test surface of the test object from the measurement data acquired in the first step, and the second step Based on the calculated position data and the design data of the test object, the third step of calculating the movement amount of the centering unit, the position data calculated in the second step, and the design data of the test object Based on the fourth step of calculating the amount of rotation of the test object, the fifth step of rotating the test lens and setting it to the adjustment direction position, and the centering unit abutted against the test object The sixth step to detect When, comprising a, a seventh step of moving the position of the paraxial curvature center of one of the test surface of the test object the centering unit.

  According to a thirteenth aspect, in the centering method according to the twelfth aspect, the position data of the test object used in the third step is a measurement value obtained by another measuring device.

  According to a fourteenth aspect of the present invention, in the centering method according to the twelfth aspect, the amount of movement of the position of the paraxial curvature center in the seventh step is calculated by the centering unit calculated in the third step. It is smaller than the amount of movement.

  The fifteenth aspect of the invention is the centering method according to the fourteenth aspect of the invention, wherein the movement amount of the position of the paraxial center of curvature in the seventh step is the value of the centering unit calculated in the third step. It is smaller than the movement amount by a certain amount.

  According to a sixteenth aspect of the present invention, in the centering method according to the fourteenth aspect, the amount of movement of the position of the paraxial curvature center in the seventh step is calculated by the centering unit calculated in the third step. It is smaller than the amount of movement by a certain percentage.

  According to a seventeenth aspect of the present invention, in the centering method according to any one of the twelfth to sixteenth aspects, a paraxial curvature of one test surface of the test object by the centering unit in the seventh step. After moving the center position, the method has a step of calculating the distance between the position of the paraxial center of curvature and the target position. If the calculated distance is greater than or equal to a preset value, the adjustment amount is calculated based on the distance. Then, the adjustment is performed again by the centering unit, and the centering is repeated until the distance becomes a set value or less.

  The eighteenth invention is the centering method according to any one of the eleventh to sixteenth inventions, wherein the paraxial curvature center position of one test surface of the test object is moved in the seventh step. Based on this, it is detected by the measurement unit that the centering unit is in contact with the test object.

  ADVANTAGE OF THE INVENTION According to this invention, the centering method and centering mechanism which can perform centering with high precision irrespective of the shape of to-be-tested object, and an aspheric surface eccentricity measuring apparatus provided with the same are provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram schematically showing the configuration of an aspheric eccentricity measuring apparatus according to the first embodiment of the present invention. The xyz coordinate system in FIG. 1 is as shown in the upper left in the figure. Here, the y direction is a direction perpendicular to the paper surface, and the direction from the front of the paper surface to the back is positive.

  As shown in FIG. 1, the aspherical lens eccentricity measuring device 16 includes a lens holder 2, an air spindle 3, a motor 4, a rotary encoder 5, a centering member 6, a moving table 7, a spot locus detecting means 8, and a microscope moving table 9. , A contact type length measuring device 10, a moving table 11, a contact type length measuring device 12, a moving table 13, a calculation means 14 and a monitor 15.

  Here, the double-sided aspheric lens 1 is a test object. The lens holder 2 is a holding unit. The lens holder 2 holds the double-sided aspheric lens 1. The air spindle 3 rotates the lens holder 2 around the rotation shaft 17. The motor 4 rotates the air spindle 3. The air spindle 3 and the motor 4 constitute a rotating unit. The rotary encoder 5 is a measurement unit. The rotary encoder 5 detects the rotation angle of the air spindle 3.

The centering member 6 is a contact member. The centering member 6 pushes the double-sided aspheric lens 1 in a predetermined direction. The predetermined direction is a direction along the rotation axis 17, a direction perpendicular to the rotation axis 17, or these two directions. With this centering member 6, the double-sided aspherical lens 1 can be moved to adjust the position (centering adjustment) of the paraxial curvature center O _A of the test surface 1A. The moving table 7 is a moving member. The moving table 7 moves the centering member 6 in a direction along the rotation shaft 17 (x-axis direction) or in a direction perpendicular to the rotation shaft 17 (z-axis direction). Thereby, the centering adjustment of the double-sided aspherical lens 1 can be performed. The centering member 6 and the material moving table 7 constitute a centering unit.

  The spot trajectory detection means 8 irradiates each test surface 1A, 1B of the double-sided aspheric lens 1 with light and detects the trajectory of the reflected light spot. The microscope movement table 9 moves the spot trajectory detection means 8 in either the x-axis direction or the y-axis direction. By the microscope moving table 9, the spot locus detecting means 8 can move between the first position and the second position. Here, the first position is a position where the measurement optical axis coincides with the rotation axis 17 of the air spindle 3. The second position is a non-interfering position that does not interfere with the measurement of the test surfaces 1A and 1B. At the time of measurement, the spot locus detecting means 8 is retracted to the second position.

  The contact-type length measuring device 10 has a probe 10-1. The probe 10-1 measures the three-dimensional shape of the test surface 1A of the double-sided aspheric lens 1. A contact type length measuring device 10 is mounted on the moving table 11. The moving table 11 moves the contact-type length measuring device 10 in the xyz axis direction. Therefore, the contact-type length measuring device 10 can be moved to the measurement position and the retracted position. The contact-type length measuring device 12 has a probe 12-1. The probe 12-1 measures the three-dimensional shape of the test surface 1B of the double-sided aspheric lens 1. A contact type length measuring device 12 is mounted on the moving table 13. The moving table 13 moves the contact type length measuring device 12 in the xyz axis direction. Therefore, the contact-type length measuring device 12 can be moved to the measurement position and the retracted position. Note that the probe 10-1 and the probe 12-1 are spherical contacts.

The calculation means 14 performs the following processing or calculation. (1) Control of each moving table. (2) Processing of information obtained from the spot locus detecting means 8 and the rotary encoder 5. (3) Calculation of the centering adjustment amount obtained from the distance from the rotating shaft 17 to the paraxial curvature center O _A of the test surface 1A. (4) Processing of information obtained by the upper contact type length measuring instrument 10 or the lower contact type length measuring instrument 12 and the rotary encoder 5, and (5) Calculation of aspherical eccentricity. The monitor 15 displays measurement results and the like.

  The spot locus detection means 8 includes a light source 8a, a collimating lens 8b, a half mirror 8c, imaging optical systems 8d and 8f, and an image sensor 8e. The light source 8a is, for example, a lamp.

FIG. 2 is a diagram showing the configuration of the centering member 6. The centering member 6 includes a rod-shaped center pushing portion 20-1 formed in the z-axis direction and a main body 20-2 formed in the x-axis direction. The tip of the rod-shaped center pushing portion 20-1 is a spherical surface. Then, the test surface of the double-sided aspheric lens 1 is pressed by this spherical portion. For example, the test surface 1A is pressed and the double-sided aspherical lens 1 is moved. As a result, an operation of aligning the paraxial curvature center O _A of the test surface 1A with the rotation shaft 17, that is, centering adjustment can be performed.

20-2a which is the front-end | tip of the main body 20-2 is a plane. Therefore, the outer portion of the double-sided aspherical lens 1 is pressed by the flat portion 20-2a. The double-sided aspherical lens 1 can be moved by pressing the outer diameter portion. As a result, an operation of aligning the paraxial curvature center O _A of the test surface 1A with the rotation shaft 17, that is, centering adjustment can be performed.

  In the centering adjustment, either the rod-shaped center pushing part 20-1 or the flat part 20-2a may be used. Which one is used is determined based on whether or not an angle (hereinafter referred to as a contact angle) between the normal line of the test surface and the rotation shaft 17 at a predetermined position (point) is greater than 45 degrees. This predetermined position is a position (point) at which the lens holder 2 and the test surface 1B come into contact with each other. At that time, if the design data of the surface to be examined and the shape data of the lens holder 2 are input to the calculation means in advance, the angle at a predetermined position can be calculated. Therefore, the above determination can be made by the calculation means 14.

When the contact angle is smaller than 45 degrees, the inclination of the test surface 1B at the contact point is gentle. Therefore, the double-sided aspherical lens 1 is pushed in the direction perpendicular to the rotation shaft 17 using the flat surface portion 20-2a. Thereby, the double-sided aspherical lens 1 can be smoothly moved on the lens holder 2. At that time, bi-aspherical lens 1 can be regarded as being substantially rotation as a fulcrum paraxial curvature center O _B of the test surface 1B. Therefore, by the above operation, it is possible to adjust the position of the paraxial curvature center O _A of the test surface 1A.

On the other hand, when the contact angle is larger than 45 degrees, the inclination of the test surface 1B at the contact point is steep. Therefore, even if the double-sided aspherical lens 1 is pushed in the direction perpendicular to the rotation shaft 17, the double-sided aspherical lens 1 does not move smoothly on the lens holder 2. Therefore, bi-aspherical lens 1 does not rotate as a fulcrum paraxial curvature center O _B of the test surface 1B.

Therefore, the double-sided aspherical lens 1 is pushed in the direction along the rotation axis 17 using the rod-shaped center pushing portion 20-1. Thereby, the double-sided aspherical lens 1 can be smoothly moved on the lens holder 2. As a result, it is possible to adjust the position of the paraxial curvature center O _A of the test surface 1A.

  In the actual centering adjustment operation, the friction varies depending on the shape of the portion where the lens holder 2 and the test surface are in contact with each other and the material of the lens holder 2. Therefore, the double-sided aspherical lens 1 is moved in both the direction perpendicular to the rotation shaft 17 and the direction along the rotation shaft 17. Then, after determining the direction in which the double-sided aspherical lens 1 rotates more smoothly, it may be determined whether the centering adjustment is performed in either direction.

  The lens holder 2 has a cylindrical shape. FIG. 1 shows a cross section of the lens holder 2. The upper end surface of the lens holder 2 has an annular shape. This end face is orthogonal to the central axis of the lens holder 2. The lens holder 2 has an inner contact portion and an outer contact portion. The inner contact portion includes a circular edge that is a boundary between the upper end surface and the inner peripheral surface. Further, the outer contact portion is composed of a circular edge that is a boundary between the upper end surface and the outer peripheral surface. Further, the center point of both circular contact portions is on the rotation shaft 17 of the air spindle 3.

  The contact-type length measuring devices 10 and 12 are arranged so as to come into contact with the test surface 1A or 1B at a position away from the rotating shaft 17 of the air spindle 3 in the negative direction of the y axis by a specific distance. At the measurement position, the probe 10-1 is in contact with the test surface 1A and the probe 12-1 is in contact with the test surface 1B. In this state, the contact-type length measuring device 10 measures the position in the z-axis direction (the direction along the rotation axis 17). Moreover, the contact-type length measuring device 12 measures the position regarding 12-1 z-axis direction (direction along the rotating shaft 17). Then, the contact-type length measuring devices 10 and 12 send the respective position information to the calculation means 14. The direction from the rotation shaft 17 to the probe 10-1 or the rotation shafts 17 to 12-1 is not limited to the negative value in the y direction.

  In the measurement, the double-sided aspherical lens 1 rotates about the rotation shaft 17. At this time, each rotation is measured by the rotary encoder 5. Therefore, the calculation means 14 acquires the position information sent from the contact-type length measuring devices 10 and 12 in synchronization with the rotation angle measured by the rotary encoder 5. As a result, the calculation means 14 obtains the three-dimensional shape data of the test surfaces 1A and 1B. It can be acquired in a ring shape.

  A half mirror 8c is provided in the spot locus detecting means 8. The half mirror 8c transmits the light emitted from the light source 8a toward the double-sided aspheric lens 1 and reflects the return light from the test surface 1A toward the image sensor 8e. That is, the half mirror 8 c constitutes a separation optical element that separates light traveling toward the double-sided aspherical lens 1 and light returning from the double-sided aspherical lens 1. Such a separation optical system is not limited to a half mirror. For example, a prism may be used instead of the half mirror.

  In FIG. 1, the imaging optical system 8d is drawn with a single lens. However, the image forming optical system 8d is usually configured by a plurality of lens groups (may be a plurality of lenses). Moreover, some of the plurality of lens groups may be movable along the optical axis. In this way, the light from the light source 8a can be converged to a desired point by adjusting the position of the lens group. In order to adjust the position of the lens group, a stage using a motor or the like may be used. At this time, if the stage is controlled by the computing means 14, the lens group can be moved by remote control.

The light emitted from the light source 8a reaches the double-sided aspherical lens 1 through the collimating lens 8b, the half mirror 8c, and the imaging optical element 8d. And it converges on the paraxial curvature center of the surface to be measured of the surface aspherical lens 1. In other words, the optical system of the spot trajectory detecting means 8 is configured to converge to the paraxial curvature center of the surface to be measured of the surface aspherical lens 1. In Figure 1, paraxial curvature center O _A or of the test surface 1A, so as to converge to the paraxial curvature center O _B of the test surface 1B, light emitted from the light source 8a is irradiated. The light reflected by the test surface 1A or 1B is converged on the image sensor 8e via the imaging optical system 8d, the half mirror 8c, and the imaging optical system 8f, thereby forming a spot image.

Here, the paraxial curvature center O _A of the test surface 1A is not located on the rotary shaft 17. In this case, the spot image draws a circle on the imaging surface in accordance with the rotation of the double-sided aspheric lens 1. That is, the “swinging” of the spot image occurs.

The position of the spot image detected by the spot trajectory detection means 8 is sent to the calculation means 14. In addition, the rotary encoder output (the rotation angle of the double-sided aspherical lens 1) is also sent to the computing means 14 in order to associate “swinging” with the rotation of the double-sided aspherical lens 1. Based on such information, the calculation means 14 calculates the position and direction of the paraxial curvature center O _A of the test surface 1A from the rotation axis 17. In the centering adjustment, the rotational position and the adjustment amount of the double-sided aspherical lens 1 are calculated based on the distance and the direction of the paraxial curvature center O _A of the test surface 1A with respect to the rotation shaft 17.

Next, calculation of the adjustment amount by the centering member 6 performed by the calculation means 14 will be described. The calculated distance between the paraxial curvature center O _A of the test surface 1A to the rotary shaft 17 is used. First, a case where the contact angle is larger than 45 degrees will be described. In this case, centering adjustment is performed by pushing the double-sided aspherical lens 1 in the direction along the rotation shaft 17. The calculation of the adjustment amount at this time will be described with reference to FIG.

The data of the double-sided aspheric lens 1
Paraxial curvature of test surface 1A: R _A [mm]
Paraxial curvature of test surface 1B: R _B [mm]
Thickness: d [mm]
And

When the distance from the rotation axis 17 of the paraxial center of curvature O _A of the test surface 1A is L _A [mm], an adjustment amount L _P [mm] is obtained. Here, the adjustment amount L _P [mm] is a distance in the xz plane where the paraxial curvature center O _A exists as shown in FIG. In addition, for the sake of simplification of the calculation and assuming that the adjustment amount is a minute region, the following is considered.

First, it is assumed that the aspheric axis of the test surface 1B coincides with the rotation axis 17. For centering, even if the position of the double-sided aspherical lens 1 changes, the aspherical axis of the test surface 1B remains coincident with the rotation axis 17 (z-axis). Pressing the direction along the test surface 1A to the rotary shaft 17 by the centering member 6, around the paraxial curvature center O _B of the test surface 1B which is supported by the lens holder 2, bi-aspherical lens 1 times Shall be performed.

The adjustment amount L _P [mm] is calculated based on the above assumption. Let r _ADJ [mm] be the distance from the rotating shaft 17 to the point B at which one of the test surfaces 1A is pressed by the centering member 6. A point where the test surface 1A intersects the rotation axis 17 is defined as A (0, 0).

Centering member 6 is set to B (x2, z2) and that pushes the test surface 1A, in a direction along the centering member 6 to the rotation shaft 17 when pressing L _P [mm], only θ around the point O _B a point when the rotational movement and D (x4, z4), a straight line passing through the point O _B and the point D is the point of intersection between a straight line perpendicular to the z axis passing through the point B C (x3, z3) And Distance from the point A to the paraxial curvature center O _B is R _A [mm]. Then, the distance R ₁ from the point O _B to the point O _A can be approximated by the following expression.

When the paraxial curvature center O _A of the test surface 1A is moved by L _A [mm], the angle change θ [degree] generated at that time can be approximated by the following equation.

The point O _A to pivot about the point O _B, strictly speaking also changes in the direction of the axis of rotation 17. However, the amount of movement in the direction along the rotation shaft 17 is not considered here, assuming that the adjustment amount is very small.

  Next, the coordinates (x2, z2) of the point B are obtained from the aspherical expression of the one test surface 1A.

x2 = r _ADJ
z2 = ASP _A (r _ADJ ) (3)
ASP _A (x) in the expression (3) represents an aspheric expression of the test surface 1A.

The angle α [degree] formed by the straight line O _B -B and the rotation axis 17 (z axis) is obtained as follows.

Since a straight line passing through the point O _B and the point C is the angle between the rotary shaft 17 becomes (α + θ) [degrees], it can be derived the following equation.

∴x3 = − (R _A + Z2) × tan (α + θ) (5)
Equation of a straight line passing through the point O _B and the point C is given by the following equation.

Point O _B is at the center, a circle passing through the point B is obtained by the following equation.

x ² + (z−z1) ² = (− R _A −Z2) ² + r _ADJ ² (7)
Since the point D is a point on the arc that can be expressed by the above equation (7), the point D (x4, z4) can be obtained by the equations (6) and (7).

From the above result, the adjustment amount L _P can be obtained by the following equation.

L _P = z2−z4 [mm] (8)
In the above description, the design value is used as the data of the double-sided aspheric lens 1, but the measurement value with another measurement device may be used. By calculating the adjustment amount using a value close to the actual double-sided aspheric lens 1, it is possible to calculate a more accurate adjustment amount.

  Next, a case where the contact angle is smaller than 45 degrees will be described. In this case, centering is performed by pushing the double-sided aspherical lens 1 in a direction perpendicular to the rotation shaft 17. Calculation of the adjustment amount at that time will be described with reference to FIG.

As data of the double-sided aspherical lens 1 Paraxial curvature of the test surface 1A: R _A [mm]
Paraxial curvature of test surface 1B: R _B [mm]
Thickness: d [mm]
And (Each data uses design values as before, or measured values from other measuring devices)
An adjustment amount L _P [mm] when the distance from the rotation axis 17 of the paraxial curvature center O _A of the test surface 1A is L _A [mm] is obtained. Here, the adjustment amount L _P [mm] is considered on the xz plane where the paraxial curvature center O _A exists as shown in FIG. In addition, for the sake of simplification of the calculation and assuming that the adjustment amount is a minute region, the following is considered.

First, it is assumed that the aspheric axis of the test surface 1B coincides with the rotation axis 17 (z axis). For centering, even if the position of the double-sided aspherical lens 1 changes, the aspherical axis of the test surface 1B remains coincident with the rotation axis 17 (z-axis). Pressing outer peripheral portion of the aspherical lens 1 in a direction perpendicular to the rotation axis 17 by the centering member 6, around the paraxial curvature center O _B of the test surface 1B which is supported by the lens holder 2, a bi- The spherical lens 1 is assumed to rotate. The position pushed by the position adjusting member 6 is assumed to be a position from the surface top position A (0, 0) to H of the test surface 1B.

At this time, if the paraxial curvature center O _A of the test surface 1A is moved by L _A [mm], the angle change θ [degree] at that time can be approximated by the following equation.

The point O _A to pivot about the point O _B, strictly speaking also changes in the direction of the axis of rotation 17. However, the amount of movement in the direction of the rotating shaft 17 is not considered here, assuming that the adjustment amount is very small.

Assuming that the intersection of the straight line passing through the point O _B and the point O _A and the straight line passing through the point H at the position pressed by the centering member 6 and perpendicular to the rotation axis 17 (z axis) is B, θ is It can be expressed as

From the expressions (10) and (11), L _P is as follows.

  Since the adjustment amount can be obtained, the calculation means 14 obtains the next adjustment direction based on the data of the double-sided aspheric lens 1.

  First, calculation of the adjustment direction when the contact angle is greater than 45 degrees will be described with reference to FIG.

As shown in FIG. 1, the centering member 6 is located away from the rotating shaft 17 in the positive direction of the x-axis. Therefore, the double-sided aspherical lens 1 may be rotated to set the position of the paraxial center of curvature O _A of the test surface 1A in the positive direction or the negative direction on the x-axis.

And a position pressed by the centering member 6 as a fulcrum paraxial curvature center O _B of the test surface 1B, the position relationship of the paraxial curvature center O _A of the test surface 1A, as follows.

[A] point O _A is below than the point O _B, if pressing one of the test surface 1A at a positive position of the x-axis on the lower side (Figure 5 (a)). In this case, when the double-sided aspherical lens 1 is pushed down in the direction along the rotation axis 17, the paraxial curvature center O _A moves in the negative x-axis direction.

When [B] point O _A is located above the point O _B, pressing one of the test surface 1A at a positive position of the x-axis on the lower side (Figure 5 (b)). In this case, when the double-sided aspherical lens 1 is pushed down in the direction along the rotation axis 17, the paraxial center of curvature O _A moves in the positive x-axis direction.

  Similarly, calculation of the adjustment direction when the contact angle is smaller than 45 degrees will be described with reference to FIG.

As shown in FIG. 1, the centering member 6 is located away from the rotating shaft 17 in the positive direction of the x-axis. Therefore, the double-sided aspherical lens 1 may be rotated to set the position of the paraxial center of curvature O _A of the test surface 1A in the positive direction or the negative direction on the x-axis.

And a position pressed by the centering member 6 as a fulcrum paraxial curvature center O _B of the test surface 1B, the position relationship of the paraxial curvature center O _A of the test surface 1A, as follows.

[C] point O _A is below than the point O _B, when pressing the double-sided aspherical lens 1 in the negative direction of the x-axis in the positive position of the x-axis (FIG. 6 (a)). In this case, when the double-sided aspheric lens 1 is pushed in the negative x-axis direction, the paraxial curvature center O _A moves in the negative x-axis direction.

[D] point O _A located above the the point O _B, when pressing the double-sided aspherical lens 1 at the positive position of the x-axis in the negative direction of the x axis (Figure 6 (b)). In this case, when the double-sided aspheric lens 1 is pushed in the negative x-axis direction, the paraxial curvature center O _A moves in the positive x-axis direction.

The moving direction of the centering member 6, the direction of movement of the paraxial curvature center O _A of the test surface 1A is determined by the [D] from the [A]. Therefore, it is sufficient to set the paraxial curvature center O _A of the test surface 1A positive direction on the x-axis, in either the negative direction position. Therefore, it becomes clear how many times the double-sided aspheric lens 1 should be rotated.

Next, the centering adjustment procedure will be described with reference to FIGS. First, a case where the contact angle is larger than 45 degrees will be described. This is a case where centering adjustment is performed by pushing the double-sided aspherical lens 1 in the direction along the rotation axis 17. (Positional relationship between the O _B and O _A is an aspherical lens which corresponds to the previously described [A])
[A] The double-sided aspherical lens 1 is rotated around the rotation shaft 17. Here, θ _OA is an angle formed by a line connecting the paraxial center of curvature O _{A of the} surface 1A to be examined and the point O with the x axis. The angle θ _OA is an angle on the xy plane. The double-sided aspheric lens 1 is rotated according to the angle θ _OA so that the paraxial center of curvature O _A coincides with the x-axis. O _A shown in FIG. 7A represents a spot image of the paraxial center of curvature O _{A. A} circle passing through OA is a movement locus drawn by the spot image when the double-sided aspherical lens 1 is rotated. Further, the horizontal axis of the alternate long and short dash line indicates the x-axis, and the vertical axis indicates the y-axis. In FIG. 7A, the intersection point O between the x axis and the y axis indicates the position of the rotating shaft 17. Therefore, the centering is an adjustment that makes the paraxial curvature center O _A coincide with or close to the point O.

Here, the point O _A located below the point O _B, and corresponds to the case to push along the double-sided aspherical lens 1 on the rotation shaft 17 at the positive position of the x-axis. Therefore, the centering direction is a direction in which the double-sided aspheric lens 1 is pushed down along the rotation axis 17.

Therefore, as shown in FIG. 7B, the double-sided aspherical lens 1 is rotationally moved so that the paraxial curvature center O _{A of} one test surface 1A coincides with the positive direction of the x-axis. . And when it corresponds, the double-sided aspherical lens 1 is stopped.

  [B] The position of the centering member 6 is moved from the initial position to the adjustment start position. This movement is performed by the movement table 7. As shown in FIG. 7C, the adjustment position is a position that is away from the rotation shaft 17 by a set distance and does not contact one of the test surfaces 1A.

[C] The centering member 6 is brought into contact with the double-sided aspherical lens 1. For this, the centering member 6 is gradually moved along the rotation shaft 17 by the moving table 7. At the same time, the spot image is observed by the spot trajectory detecting means 8. When the tip 20-1 of the centering member 6 comes into contact with the test surface 1A, the spot of the paraxial curvature center O _A moves by a certain amount. Therefore, the contact of the tip portion 20-1 can be detected by the movement.

Here, the spot trajectory detection means 8 captures the position of the spot image, and the video output is analyzed by image processing to determine contact. Therefore, since it is not necessary to add another sensor to the apparatus in order to detect contact, the apparatus configuration is not complicated. Further, the posture of the double-sided aspherical lens 1 is slightly changed by the contact. Therefore, the distance between the paraxial center of curvature O _A and the point O is obtained again, and a new adjustment amount is obtained based on the distance.

[D] The centering adjustment of the double-sided aspherical lens 1 is performed based on the adjustment amount obtained by the calculation means 14. The centering member 6 is moved downward in the direction along the rotating shaft 17 by the adjustment amount obtained by the calculation means 14. When the distance obtained by calculation is L _P [mm], the centering adjustment method can be performed by any of the following methods [1], [2], and [3].

[1] The centering member 6 is pushed down by L _P [mm]. After the centering member 6 is moved by L _P [mm], the distance L _A [mm] between the paraxial center of curvature O _A and the point O in the xy plane is measured (confirmed) by the spot locus detecting means 8. Here, it is assumed that the value of L _A is larger than a certain distance L _B (set in advance) [mm]. In this case, the centering member 6 is once removed from the double-sided aspherical lens 1, and (a) to (d) are repeated, and the centering adjustment is repeated so as to be smaller than the set L _B [mm]. Do.

After the centering is completed, the centering member 6 is returned to the initial position. If this method is used, if the data of the double-sided aspherical lens 1 matches the actual lens shape and the distance from the paraxial center of curvature O _A to the point O is strictly determined, the centering adjustment amount L _P [Mm] completes the centering operation once.

[2] The centering member 6 is pushed down by a distance smaller than L _P [mm] by a certain value. For example, the centering member 6 is moved by a value obtained by subtracting a certain distance L _C (set in advance) [mm] with respect to the movement amount of L _P [mm]. That is, the centering member 6 is pushed down by L _P −L _C [mm] in the direction along the rotation shaft 17.

After the centering member 6 is moved, the distance L _A [mm] between the paraxial center of curvature O _A and the point O is confirmed by the spot locus detecting means 8. Then, when L _A [mm] becomes smaller than the set value L _B [mm], the centering adjustment is terminated. The distance L _C [mm] is set so that the centering adjustment is terminated when the distance L _A [mm] between the point O and the paraxial center of curvature O _A is equal to or less than L _B [mm]. , L _C [mm] needs to be smaller than L _B [mm].

With this method, the paraxial curvature center O _A does not pass through the point O due to the centering operation. Therefore, the centering operation is not performed again by changing the rotational position of the double-sided aspheric lens 1 with respect to the rotational shaft 17. That is, since it is not necessary to remove the centering member 6 from the double-sided aspherical lens 1, it is possible to accurately perform centering adjustment in a short time.

[3] The centering member 6 is pushed down by a certain distance of L _P [mm]. For example, the centering member 6 is moved by a distance that is smaller by a certain fixed ratio L _D (set in advance) with respect to the movement amount of L _P [mm]. (Here, L _D <1.0.) That is, it is pushed down in the direction along the rotation axis 17 by L _P × L _D [mm]. The subsequent operation is the same as [2] above.

After movement of the centering member 6, the distance L _A [mm] between the paraxial center of curvature O _A and the point O is confirmed by the spot locus detecting means 8. Then, the centering adjustment is terminated when L _A [mm] becomes smaller than the set value L _B [mm]. Even if this method is used, the paraxial curvature center O _A does not pass through the point O due to the centering operation as in [2] above. Therefore, the centering operation is not performed again by changing the rotational position of the double-sided aspheric lens 1 with respect to the rotational shaft 17. That is, since it is not necessary to remove the centering member 6 from the double-sided aspherical lens 1, it is possible to accurately perform centering adjustment in a short time.

Next, a case where the contact angle is smaller than 45 degrees will be described with reference to FIG. This is a case where centering adjustment is performed by pushing the double-sided aspherical lens 1 in a direction perpendicular to the rotation shaft 17. (Positional relationship between the O _B and O _A is an aspherical lens which corresponds to the previously described [C])
[A] The double-sided aspherical lens 1 is rotated around the rotation shaft 17. Here, θ _OA is an angle formed by a line connecting the paraxial center of curvature O _{A of the} surface 1A to be examined and the point O with the x axis. The angle θ _OA is an angle on the xy plane. The double-sided aspheric lens 1 is rotated according to the angle θ _OA so that the paraxial center of curvature O _A coincides with the x-axis. O _A shown in FIG. 8A represents a spot image of the paraxial curvature center O _{A. A} circle passing through OA is a movement locus drawn by the spot image when the double-sided aspherical lens 1 is rotated. Further, the horizontal axis of the alternate long and short dash line indicates the x-axis, and the vertical axis indicates the y-axis. In FIG. 8A, the intersection point O between the x axis and the y axis indicates the position of the rotating shaft 17. Therefore, the centering is an adjustment that makes the paraxial curvature center O _A coincide with or close to the point O.

Here, the point O _A located below the point O _B, and corresponds to the case where pressing the double-sided aspherical lens 1 in a direction perpendicular to the rotation axis 17 at the positive position of the x-axis. Therefore, the centering direction is the direction in which the double-sided aspheric lens 1 is pushed to the left along the x-axis (negative direction).

Therefore, as shown in FIG. 8B, the double-sided aspherical lens 1 is rotationally moved so that the paraxial curvature center O _{A of} one test surface 1A coincides with the positive direction of the x-axis. . And when it corresponds, the double-sided aspherical lens 1 is stopped.

  [B] The position of the centering member 6 is moved from the initial position to the adjustment start position. This movement is performed by the movement table 7. Among the adjustment start positions, the position in the direction along the rotation axis 17 is a height that substantially matches the outer peripheral portion of the double-sided aspheric lens 1. Further, among the adjustment start positions, the position in the direction orthogonal to the rotation axis 17 is a position separated by an arbitrary distance from the test surface 1A.

[C] The centering member 6 is brought close to the double-sided aspherical lens 1. This is because the moving table 7 moves the centering member 6 gradually in a direction perpendicular to the rotation shaft 17. At this time, the centering member 6 is moved to a predetermined position L _E (set in advance) [mm] by the moving table 7. Here, the value of L _E [mm] is set to a larger value with a little margin than the sum of both in consideration of the radius of the outer periphery of the double-sided aspherical lens 1 and the outer diameter eccentricity. That is, the flat portion 20-2a of the centering member is set to a position where the outer periphery of the double-sided aspherical lens 1 is not pushed. Thus, up to a predetermined position L _E, the centering member 6 can be moved at high speed.

[D] The centering member 6 is brought into contact with the double-sided aspherical lens 1. The centering member 6 is gradually moved in a direction perpendicular to the rotation shaft 17 by the moving table 7. At the same time, the spot image is observed by the spot trajectory detecting means 8. When the flat surface portion 20-2a of the centering member 6 comes into contact with the outer peripheral portion of the double-sided aspherical lens 1, the spot of the paraxial curvature center O _A moves by a certain amount. Therefore, the contact of the flat surface portion 20-2a can be detected by the movement.

Here, the spot trajectory detection means 8 captures the position of the spot image, and the video output is analyzed by image processing to determine contact. Therefore, since it is not necessary to add another sensor to the apparatus in order to detect contact, the apparatus configuration is not complicated. Further, the posture of the double-sided aspherical lens 1 is slightly changed by the contact. Therefore, the distance between the paraxial center of curvature O _A and the point O is obtained again, and a new adjustment amount is obtained based on the distance.

[E] Centering adjustment of the double-sided aspherical lens 1 is performed based on the adjustment amount obtained by the calculation means 14. Centering is performed by moving the centering member 6 by L _P [mm] in a direction orthogonal to the rotation shaft 17 by the adjustment amount obtained by the calculation means 14. When the distance obtained by calculation is L _P [mm], the centering adjustment method can be performed by any of the following methods [1], [2], and [3].

[1] The centering member 6 is brought closer to the direction perpendicular to the rotation shaft 17 by L _P [mm]. After the centering member 6 is moved by L _P [mm], the distance L _A [mm] between the paraxial center of curvature O _A and the point O is measured (confirmed) by the spot locus detecting means 8. Here, it is assumed that the value of L _A is larger than a certain distance L _B (set in advance) [mm]. In this case, the centering member 6 is once removed from the double-sided aspherical lens 1, and (a) to (f) are repeated, and the centering adjustment is repeated so as to be smaller than the set L _B [mm]. Do.

After the centering is completed, the centering member 6 is returned to the initial position. With this method, if the data of the double-sided aspherical lens 1 matches the actual lens shape and the distance from the paraxial center of curvature O _A to the point O is strictly determined, the centering adjustment amount L _P [Mm] completes the centering operation once.

[2] The centering member 6 is brought closer to the rotating shaft 17 by a distance smaller than L _P [mm] by a certain value. For example, the centering member 6 is moved by a value obtained by subtracting a certain distance L _C (set in advance) [mm] with respect to the movement amount of L _P [mm]. That is, the centering member 6 is moved by L _P −L _C [mm] in a direction perpendicular to the rotation shaft 17.

After the centering member 6 is moved, the distance L _A [mm] between the paraxial center of curvature O _A and the point O is confirmed by the spot locus detecting means 8. Then, when L _A [mm] becomes smaller than the set value L _B [mm], the centering adjustment is terminated. The distance L _C [mm] is set so that the centering adjustment is terminated when the distance L _A [mm] between the point O and the paraxial center of curvature O _A is equal to or less than L _B [mm]. , L _C [mm] needs to be smaller than L _B [mm].

With this method, the paraxial center of curvature O _A does not pass through the point O during centering. Therefore, the centering operation is not performed by changing the rotational position of the double-sided aspheric lens 1 with respect to the rotation shaft 17. That is, since the centering member 6 is not once removed from the double-sided aspherical lens 1, it is possible to reliably perform centering adjustment with high accuracy in a short time.

[3] The centering member 6 is brought closer to the rotating shaft by a distance of a constant ratio of L _P [mm]. For example, the centering member 6 is moved by a distance that is smaller by a certain fixed ratio L _D (set in advance) with respect to the movement amount of L _P [mm]. (Here, L _D <1.0.) That is, L _P × L _D [mm] is moved in the direction perpendicular to the rotating shaft 17. The subsequent operation is the same as [2] above.

After movement of the centering member 6, the distance L _A [mm] between the paraxial center of curvature O _A and the point O is confirmed by the spot locus detecting means 8. Then, the centering adjustment is terminated when L _A [mm] becomes smaller than the set value L _B [mm]. Even if this method is used, the paraxial center of curvature O _A does not pass through the point O at the time of centering as in [2] above. Therefore, the rotational position of the double-sided aspheric lens 1 with respect to the rotation shaft 17 is changed, and the centering adjustment operation is not performed again. That is, since it is not necessary to remove the centering member 6 from the double-sided aspherical lens 1, it is possible to reliably perform centering adjustment in a short time.

If the centering adjustment as described above is performed, the paraxial curvature center O _A of the test surface 1A coincides with the rotation axis 17 or about several μm regardless of the shape of the test surface 1B that is in direct contact with the lens holder 2. It becomes possible to adjust to.

  After the centering adjustment, the aspheric eccentricity of the double-sided aspheric lens 1 is measured. The procedure will be described with reference to FIGS. 9, 10 (a), (b) and FIGS. 11 (a), (b).

[A] Paraxial center of curvature measurement process FIG. 9 shows how the center of paraxial curvature of the double-sided aspherical lens 1 is measured. The spot trajectory detection means 8 is moved to the measurement position by the movement table 9. Here, the measurement position is a position where the optical axis of the spot locus detecting means 8 substantially coincides with the rotation axis 17 of the air spindle 3. The position of the lens 8d of the spot locus detecting means 8 is adjusted, and the measurement light beam is made incident on the test surface 1A. At this time, the measurement light beam is made to enter perpendicularly to the paraxial spherical surface near the symmetry axis of the surface 1A to be examined. This is the same as the measurement light beam is converged on the paraxial center of curvature O _A of the test surface 1A.

  Here, it is assumed that the test surface 1 </ b> A is in an ideal state where there is no shift and tilt with respect to the rotation shaft 17. In this state, the measurement light beam perpendicularly incident on the test surface 1A is reflected vertically and returns on the same optical path. This light beam passes through the imaging optical system 8d and is reflected by the half mirror 8c. Then, an image is formed on the image sensor 8e by the imaging optical system 8f to form a spot image. Therefore, the air spindle 3 is rotated by the motor 4. In this case, the spot image is always at a fixed position.

  On the other hand, it is assumed that there is a shift and a tilt on the test surface 1A. To be precise, the spot trajectory detecting means 8 irradiates the measurement light beam in the range of the paraxial curvature that can be regarded as a substantially spherical surface. Therefore, it is not necessary to consider the item of tilt that occurs only on the aspherical surface, and it is sufficient to consider only the shift.

  When shift and tilt are present on the test surface 1A, the spot image rotates to draw a circle on the image sensor 8e. The radius of the circle (running around) at this time is an amount obtained by multiplying the shift amount of the paraxial curvature center of the surface 1A to be measured by the observation optical magnification of the spot locus detecting means 8.

While the air spindle 3 is rotated by the motor 4, the output of the image sensor 8 e and the output of the rotary encoder 5 are input to the calculation means 14. Calculating means 14 calculates the shift amount and direction of paraxial curvature center O _A of the test surface 1A. In this calculation, the radius of shake of the spot image and the rotational position of the double-sided aspheric lens 1 at each point from the shake center are used.

Next, the configuration of the optical system of the spot locus detecting means 8 is changed. As a result, the measurement light beam is not converged toward the paraxial center of curvature O _A of the test surface 1A. That is, this measurement light beam is perpendicularly incident on a paraxial spherical surface near the symmetry axis of the surface 1B to be examined. This is the same state as the paraxial curvature center O _B of the test surface 1B, which is the measuring light beam converges. The measurement light beam reflected by the test surface 1B passes through the imaging optical system 8d and is reflected by the half mirror 8c. Then, an image is formed on the image sensor 8e by the imaging optical system 8f to form a spot image.

In this state, the air spindle 3 is rotated by the motor 4. Then, the spot image is rotated in accordance with the movement of the paraxial curvature center O _B of the test surface 1B. At this time, the movement of the spot image is affected by the shift of the paraxial curvature center O _A of the test surface 1A.

While the air spindle 3 is rotated by the motor 4, the output of the image sensor 8 e and the output of the rotary encoder 5 are input to the calculation means 14. Calculating means 14 calculates the shift amount and direction of paraxial curvature center O _B of the test surface 1B by the computing unit 14. In this calculation, whirling radius of the spot image, the information of the rotational position of the double-sided aspherical lens 1 at each point from the center whirling, and the shift of the paraxial curvature center O _A of the test surface 1A of the previously obtained The quantity and direction, the paraxial radius of curvature, the thickness, and the refractive index of the test surface 1A and the test surface 1B are used.

This calculation when the person shift amount of paraxial curvature center O _A of the test surface 1A is small, the shift amount and the direction of the paraxial curvature center O _B of the test surface 1B can be accurately obtained. Therefore, the centering adjustment of the test surface 1A is important.

According to the present embodiment, if the test surface 1A is centered and adjusted, the paraxial curvature center O _A can be made to coincide or substantially coincide with the rotating shaft 17 accurately in a short time. For example, the paraxial curvature center O _A can be made to coincide with the rotating shaft 17 with an error within several μm. As a result, it is possible to accurately calculate the position of the paraxial curvature center O _B of the test surface 1B.

[B] Three-dimensional shape measurement process (test surface 1A side)
FIGS. 10A and 10B show how the three-dimensional shape of the test surface 1A is measured. First, the spot trajectory detection means 8 is moved to the retracted position by the movement table 9. As shown in FIG. 10A, this position is a position that is not far from the rotary shaft 17 and does not interfere with the shape measurement by the contact type length measuring device 10. Next, preparation for measurement with the contact-type length measuring device 10 is started. As shown in FIG. 10B, the probe 10-1 of the contact type length measuring device 10 is moved on the test surface 1 </ b> A by the moving table 11. At this time, the probe 10-1 is located on the outer peripheral portion of the double-sided aspheric lens 1 (the distance from the rotation shaft 17 is a desired position). In FIG. 10, the probe 10-1 is in a position in the negative direction of the y-axis. Then, the probe 10-1 is moved downward to bring the probe 10-1 into contact with the test surface 1A.

  In this state, the air spindle 3 is rotated by the motor 4. Then, the contact-type length measuring device 10 measures the length of the test surface 1A. At the same time, the rotational position of the double-sided aspheric lens 1 is detected by the rotary encoder 5. Then, the length measurement value and the rotation position are input to the calculation means 14, and the three-dimensional shape data of the surface 1A to be measured is obtained. The data obtained at this time is ring-shaped data.

[C] Three-dimensional shape measurement process (test surface 1B side) (see FIGS. 11A and 11B)
FIGS. 11A and 11B show how the three-dimensional shape of the test surface 1A is measured. With the moving table 11, the probe 10-1 of the contact-type length measuring device 10 is separated from the test surface 1A. Then, the contact-type length measuring device 10 is moved to the retracted position. Subsequently, preparation for measurement with the contact-type length measuring device 12 is started. The contact-type length measuring device 12 that has been at the retracted position is moved to the measuring position by the moving table 13. As shown in FIG. 11B, the probe 12-1 of the contact-type length measuring device 12 is moved below the test surface 1B by the moving table 13. At this time, the probe 12-1 is located on the outer peripheral portion of the double-sided aspheric lens 1 (the distance from the rotation shaft 17 is a desired position). In FIG. 11, the probe 12-1 is at a position in the negative direction of the y-axis. Then, the probe 12-1 is moved upward to bring the probe 12-1 into contact with the test surface 1B.

  In this state, the air spindle 3 is rotated by the motor 4. Then, the contact-type length measuring device 12 measures the length of the test surface 1B. At the same time, the rotational position of the double-sided aspheric lens 1 is detected by the rotary encoder 5. Then, the length measurement value and the rotation position are input to the calculation means 14, and the three-dimensional shape data of the surface 1B to be measured is obtained. The data obtained at this time is ring-shaped data.

[D] Aspheric Decentration Calculation Step In this step, the calculation means 14 calculates the amount of aspheric eccentricity and its direction for each test surface. Then, the calculation result is displayed on the monitor 15. In calculating the aspheric eccentricity and its direction, the shift amount and direction of the paraxial curvature center O _A of the test surface 1A, the three-dimensional shape data of the test surface 1A, and the paraxial curvature center O of the test surface 1B The shift amount of _B and the direction thereof, the measurement result of the three-dimensional shape data of the test surface 1B, and the paraxial radius of curvature and the thickness of both test surfaces are obtained from these. The shift amount and direction of the paraxial curvature center of each test surface are based on the rotation shaft 17 of the air spindle 3. Further, the three-dimensional shape data of each test surface is ring-shaped data.

According to the present embodiment, if the test surface 1A is centered and adjusted, the paraxial curvature center O _A can be made to coincide or substantially coincide with the rotating shaft 17 accurately in a short time. For example, the paraxial curvature center O _A can be made to coincide with the rotating shaft 17 with an error within several μm. As a result, it is possible to accurately calculate the position of the paraxial curvature center O _B of the test surface 1B. That is, the position of the paraxial curvature center can be obtained with high accuracy for both of the test surfaces. In this embodiment, the position and inclination of the optical axis connecting the two can be accurately obtained.

(Second Embodiment)
FIGS. 12A and 12B are views showing the configuration of the centering member 6 according to the second embodiment of the present invention. FIG. 12A is a view from the side of the centering member 6, and FIG. 12B is a view from below. The centering member 6 includes a tip member 24-1, a base portion (main body portion) 24-2, and a connecting member 24-3. The base portion (main body portion) 24-2 is a member that supports the tip member 24-1. The connecting member 24-3 is a rod-like member for connecting the tip member 24-1 and the base portion 24-2. The tip member 24-1 includes a first element 20-1, a second element 24-1a, and a strain sensor 22. The first element 20-1 has a spherical portion formed in the z-axis direction and functions as a rod-shaped center pushing portion. The second element 24-1a has a flat portion formed in the x-axis direction. The strain sensor 22 is provided between the first element 20-1 and the second element 24-1a. Furthermore, the strain sensor 23 is provided also in the connection member 24-3.

  In the above-described configuration, the double-sided aspheric lens 1 is pressed by the first element (rod-shaped center pushing portion) 20-1 or the second element (plane portion) 24-1a to perform centering adjustment. Since the operation and operation when the centering adjustment operation is performed are the same as those in the first embodiment, a description thereof will be omitted.

  In addition, the strain sensor 22 detects that the rod-shaped center pushing portion 20-1 of the centering member 6 is in contact with the surface of the double-sided aspherical lens 1. Further, the strain sensor 23 detects that the flat surface portion 24-1a of the tip member 24-1 contacts the outer peripheral portion of the double-sided aspherical lens 1. In this way, it is possible to determine the contact at a higher speed than to determine contact with the image of the spot trajectory detection means 8. Therefore, it is possible to shorten the time until contact. Moreover, in this embodiment, the strain sensor 23 is arrange | positioned at the rod-shaped connection part 24-3. Therefore, even when the double-sided aspherical lens 1 is pushed in a direction orthogonal to the rotation axis 17, it is possible to sense contact with the double-sided aspherical lens 1. In addition, with this configuration, it is possible to detect contact with the double-sided aspherical lens 1 with higher accuracy than disposing the strain sensor 23 on the base portion 24-2.

(Third embodiment)
FIG. 13 is a diagram showing the configuration of the centering member 6 according to the third embodiment of the present invention. The centering member 6 includes a rod-shaped center pushing portion 20-1 and a link mechanism portion 21. The link mechanism unit 21 includes rotating units 21-1 and 21-4 and links 21-2 and 21-3. By rotating the rotating unit 21-4 with a motor (not shown), the rotating unit 21-1 rotates through the links 21-2 and 21-3. As a result, it is possible to change the direction of the rod-shaped center pushing part 20-1 in the rotating part 21-1.

  As described above, the pressing direction of the double-sided aspheric lens 1 includes a direction along the rotation axis 17 and a direction orthogonal to the rotation axis 17. In this embodiment, as shown in FIGS. 13A and 13B, the double-sided aspherical lens 1 can be pushed by the same rod-shaped center pushing portion 20-1 in any direction. That is, even if the pressing direction changes, pressing can be performed by the same bar-shaped center pushing portion 20-1.

  Further, as shown in FIG. 14A, the direction of the rod-shaped center pushing portion 20-1 is made to be perpendicular to the normal line of the test surface 1B at the contact portion between the lens holder 2 and the test surface 1B. You can also. With this setting, the influence of friction between the lens holder 2 and the contact surface is minimized, so that the double-sided aspherical lens 1 can be efficiently pressed.

  Moreover, as shown in FIG.14 (b), you may provide the strain sensor 22 in the rod-shaped mandrel 20-1. In this way, only one strain sensor 22 is required when the double-sided aspherical lens 1 is pressed in any direction. Therefore, the electrical wiring of the device is simplified and the reliability is improved.

(Fourth embodiment)
FIG. 15 is a view showing a configuration of a centering member 6 according to the fourth embodiment of the present invention. FIG. 15 is a view of the tail pushing member 6 and the double-sided aspheric lens 1 as seen from directly above. At one end of the main body 20-2 of the centering member 6, a pressing portion 20-3 that presses the outer peripheral portion of the double-sided aspheric lens 1 is formed. The shape of the pressing portion 20-3 is an arc shape. Further, the radius of this arc is larger than the radius of the outer diameter of the double-sided aspheric lens 1. Therefore, when the centering member 6 contacts the outer peripheral portion of the double-sided aspherical lens 1, the double-sided aspherical lens 1 does not shift in the y-axis direction in the figure.

(Fifth embodiment)
FIG. 16 is a view showing a configuration of a centering member 6 according to the fifth embodiment of the present invention. The centering member 6 here includes a rod-shaped center pushing portion 20-1 and a main body 20-2. In this embodiment, the shape of the front-end | tip part of the rod-shaped center pushing part 20-1 is not a sphere but conical shape.

  In this embodiment, since the rod-shaped center pushing portion has a conical shape, even if the inclination of the test surface is large, an angle exists in the contact portion. Therefore, the frictional force does not slip and the centering adjustment can be performed with high accuracy.

  As described above, according to the present invention, centering can be performed with high accuracy regardless of whether the test object is a single-sided aspherical lens or a double-sided aspherical lens. Further, the direction of the test object is not limited, regardless of whether the surface supported by the test object is up or down.

  Further, even when the contact angle is greater than 45 degrees, the paraxial curvature center or the curvature center of the test surface can coincide with or approach the rotation axis. That is, the centering adjustment can be performed with high accuracy.

  In all of the first to fifth embodiments described above, in the centering adjustment in the direction along the rotation shaft 17, the double-sided aspherical lens 1 is pushed down from above by the centering member 6. It is not limited to this. For example, conversely, the centering adjustment may be performed so that the double-sided aspheric lens 1 is pushed up from below.

(Appendix)
The invention having the following configuration is extracted from the specific embodiment described above.

1. A holding unit for holding the test object;
A rotating unit for rotating the holding unit;
A measuring unit disposed on a rotating shaft of the rotating unit;
A centering unit provided with a contact member that contacts the test object, and a moving member that moves the contact member, and is arranged in a direction perpendicular to the rotation axis;
Comprising
The centering mechanism, wherein the moving member includes a moving mechanism that moves the contact member in a first direction along the rotation axis and in a second direction orthogonal to the first direction.

(effect)
Centering can be performed with high accuracy regardless of the shape of the test object.

2. 2. The centering mechanism according to 1, wherein the contact member has a spherical portion formed in the first direction and a flat portion formed in the second direction.

(effect)
By properly using an appropriate centering portion in accordance with the shape of the test object, centering can be reliably performed.

3. 2. The centering mechanism according to 1, wherein the moving mechanism includes a moving unit that moves the contact member in the first direction and a moving unit that moves the contact member in the second direction.

(effect)
By changing the moving direction of the centering member depending on the shape of the test object, the centering can be reliably performed.

4). The contact member includes a tip member, a main body portion for supporting the tip member, and a connecting portion for connecting the tip member and the main body portion,
The tip member includes a first element having a spherical portion formed in the first direction, a second element having a planar portion formed in the second direction, the first element, and the second element. The centering mechanism according to 1, wherein the centering mechanism is provided with a sensor that detects contact with the test object.

(effect)
By detecting that the centering member and the test object are in contact with each other by using a sensor, it is possible to determine the contact at a high speed and to shorten the time until the centering member and the test object are in contact with each other. It becomes possible.

5). The contact member includes a distal end portion, a main body portion for supporting the distal end portion, and a connecting portion that connects the distal end portion and the main body portion, and the test portion of the contact member is included in the connecting portion. 2. The centering mechanism according to 1, wherein a sensor for detecting contact with an object is provided.

(effect)
By detecting that the centering member and the test object are in contact with each other by using a sensor, it is possible to determine the contact at a high speed and to shorten the time until the centering member and the test object are in contact with each other. It becomes possible.

6). 2. The centering mechanism according to 1, wherein the contact member includes a tip portion, and a direction of a portion where the tip portion abuts on the test object can be set in an arbitrary direction.

(effect)
When centering the test object, the direction of the portion that contacts the test object is changed to the optimum direction according to the angle of the test surface, so that the friction between the holding unit and the contact surface of the test object is reduced. The influence is minimized and the test object can be pushed efficiently.

7). 7. The centering mechanism according to claim 6, wherein the contact member includes a tip portion, and a sensor that detects contact with the test object is provided at the tip portion.

(effect)
Regardless of the centering direction of the centering member, it is possible to determine contact with the test object with a single sensor.

8). The contact member includes a front end portion, a main body portion for supporting the front end portion, and a connecting portion that connects the front end portion and the main body portion, and the front end portion is formed in the second direction. 8. The centering mechanism according to 1 or 7, wherein the centering mechanism has an arc larger than an outer diameter of the test object.

(effect)
By pressing the outer peripheral part of the test object at the arc part, the test object is not laterally shifted except in the direction in which the test object is pressed.

9. The contact member includes a front end portion, a main body portion for supporting the front end portion, and a connecting portion that connects the front end portion and the main body portion, and the front end portion is formed in the first direction. The centering mechanism according to any one of 1 to 8, wherein the centering mechanism has a conical portion.

(effect)
Even if the inclination of the surface of the portion where the test object is pushed by the centering member is steep, by pushing at the corner of the conical portion, the test object does not slip during centering, so that the centering adjustment can be performed reliably.

10. An aspherical eccentricity measuring device comprising the centering mechanism according to any one of 10.1 to 9.

(effect)
Since accurate centering is possible, highly accurate aspheric eccentricity measurement is possible.

11. 11. The aspheric eccentricity measuring apparatus according to 10, wherein the aspheric eccentricity measuring apparatus includes a sensor that measures a shake amount of both surfaces of the test object.

(effect)
Even if the object to be tested is, for example, a double-sided aspherical lens or a state where the single-sided aspherical lens supports the aspherical surface, highly accurate aspherical eccentricity measurement is possible.

12. A centering method for performing centering using the centering mechanism according to any one of 12.1 to 9.
A first step of performing measurement by the measurement unit while rotating the test object;
A second step of calculating the position of the paraxial curvature center of one test surface of the test object from the measurement data acquired in the first step;
A third step of calculating a movement amount of the centering unit based on the position data calculated in the second step and the design data of the test object;
A fourth step of calculating a rotation amount of the test object based on the position data calculated in the second step and the design data of the test object;
A fifth step of setting the adjustment direction position by rotating the test object;
A sixth step of detecting that the centering unit is in contact with the object;
A seventh step of moving the position of the paraxial curvature center of one test surface of the test object by the centering unit;
A centering method comprising the steps of:

(effect)
The adjustment amount of the centering unit is calculated, and the test object is centered accordingly, so that centering can be performed accurately with one adjustment or two to three adjustments, and the time required for centering can be shortened. .

13. 13. The centering method according to 12, wherein the position data of the test object used in the third step is a measured value obtained by another measuring device.

(effect)
By using a numerical value close to the actual test object as data, the adjustment amount can be obtained accurately, and centering with higher accuracy can be performed.

14 13. The centering method according to 12, wherein a movement amount of the position of the paraxial curvature center in the seventh step is smaller than a movement amount of the centering unit calculated in the third step.

(effect)
Since the target position is not passed during the centering operation of the test object, the centering adjustment is not repeated.

15. 15. The centering according to claim 14, wherein the movement amount of the position of the paraxial center of curvature in the seventh step is smaller than the movement amount of the centering unit calculated in the third step by a certain amount. Method.

(effect)
Since the target position is not passed during the centering operation of the test object, the centering adjustment is not repeated.

16. 15. The centering according to claim 14, wherein the movement amount of the position of the paraxial center of curvature in the seventh step is smaller than the movement amount of the centering unit calculated in the third step by a certain rate. Method.

(effect)
Since the target position is not passed during the centering operation of the test object, the centering adjustment is not repeated.

17. In the seventh step, after the centering unit moves the position of the paraxial curvature center of one of the test surfaces of the test object, a step of obtaining a distance between the position of the paraxial curvature center and the target position is provided. And
When the obtained distance is greater than or equal to a preset value, an adjustment amount is calculated from the distance, the adjustment is performed again by the centering unit, and the centering is repeated until the distance becomes less than a set value. The centering method according to any one of 12 to 16.

(effect)
Since the distance to the target position is confirmed after performing the centering operation, the center position can be surely centered at a distance equal to or less than the set value without passing through the target position.

18. Based on the fact that the paraxial curvature center position of one test surface of the test object has moved in the seventh step, the measurement unit detects that the centering unit has contacted the test object. The centering method according to any one of 11 to 16, wherein:

(effect)
Without providing a special detection system, it is possible to reliably detect the contact between the centering member and the test object, and the apparatus configuration is simplified.

It is a figure which shows roughly the structure of the aspherical surface eccentricity measuring apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the structure of the centering member. It is a figure for demonstrating calculation of the adjustment amount at the time of performing centering. It is a figure for demonstrating calculation of the adjustment amount at the time of performing centering. It is a figure for demonstrating calculation of the adjustment direction at the time of performing centering. It is a figure for demonstrating calculation of the adjustment direction at the time of performing centering. It is a figure for demonstrating the procedure of centering adjustment. It is a figure for demonstrating the case where centering adjustment is performed. It is FIG. (1) for demonstrating the procedure which measures the aspherical eccentricity of a to-be-tested lens. FIG. 6 is a diagram (No. 2) for explaining the procedure for measuring the aspheric eccentricity of the lens to be examined. FIG. 10 is a diagram (No. 3) for explaining the procedure for measuring the aspheric eccentricity of the test lens. It is a figure which shows the structure of the centering member 6 which concerns on 2nd Embodiment of this invention. It is a figure which shows the structure of the centering member 6 which concerns on 3rd Embodiment of this invention. It is a figure for demonstrating the press of a to-be-tested lens. It is a figure which shows the structure of the centering member 6 which concerns on 4th Embodiment of this invention. It is a figure which shows the structure of the centering member 6 which concerns on 5th Embodiment of this invention. It is a figure for demonstrating the effect | action of the conventional aspherical lens eccentricity measuring apparatus. It is a figure for demonstrating calculation of the setting shift | offset | difference (alpha) [min] of a test lens, and direction (beta) [degree].

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Double-sided aspherical lens, 1A ... One test surface, 1B ... The other test surface, 2 ... Lens holder, 3 ... Air spindle, 4 ... Motor, 5 ... Rotary encoder, 6 ... Centering member, 7 ... Centering member moving table, 8 ... Spot locus detecting means, 9 ... Microscope moving table, 10, 12 ... Contact-type length measuring device, 11, 13 ... Contact-type measuring device moving table, 14 ... Calculation means, 15 ... Monitor, 16 ... Aspherical lens eccentricity measuring device.

Claims (18)

A centering mechanism,
A holding unit for holding the test object;
A rotating unit for rotating the holding unit;
A measuring unit disposed on a rotating shaft of the rotating unit;
A centering unit provided with a contact member that contacts the test object, and a moving member that moves the contact member, and is arranged in a direction perpendicular to the rotation axis;
Comprising
The centering mechanism, wherein the moving member includes a moving mechanism that moves the contact member in a first direction along the rotation axis and in a second direction orthogonal to the first direction.   2. The centering mechanism according to claim 1, wherein the contact member includes a spherical surface portion formed in the first direction and a flat surface portion formed in the second direction.   2. The centering device according to claim 1, wherein the moving mechanism includes a moving unit that moves the contact member in the first direction and a moving unit that moves the contact member in the second direction. mechanism. The contact member includes a tip member, a main body portion for supporting the tip member, and a connecting portion for connecting the tip member and the main body portion,
The tip member includes a first element having a spherical portion formed in the first direction, a second element having a planar portion formed in the second direction, the first element, and the second element. The centering mechanism according to claim 1, further comprising a sensor that is provided between the two and detects a contact with the test object.   The contact member includes a distal end portion, a main body portion for supporting the distal end portion, and a connecting portion that connects the distal end portion and the main body portion, and the test portion of the contact member is included in the connecting portion. The centering mechanism according to claim 1, wherein a sensor for detecting contact with an object is provided.   The centering mechanism according to claim 1, wherein the contact member includes a distal end portion, and a direction of a portion where the distal end portion abuts on the test object can be set in an arbitrary direction.   The centering mechanism according to claim 6, wherein the contact member includes a tip portion, and a sensor that detects contact with the test object is provided at the tip portion.   The contact member includes a front end portion, a main body portion for supporting the front end portion, and a connecting portion that connects the front end portion and the main body portion, and the front end portion is formed in the second direction. The centering mechanism according to claim 1, wherein the centering mechanism has an arc larger than an outer diameter of the test object.   The contact member includes a front end portion, a main body portion for supporting the front end portion, and a connecting portion that connects the front end portion and the main body portion, and the front end portion is formed in the first direction. The centering mechanism according to claim 1, further comprising a conical portion.   An aspherical eccentricity measuring device comprising the centering mechanism according to any one of claims 1 to 9.   The aspheric eccentricity measuring apparatus according to claim 10, wherein the aspherical eccentricity measuring apparatus includes a sensor that measures a shake amount of both surfaces of the test object. A centering method for performing centering using the centering mechanism according to any one of claims 1 to 9,
A first step of performing measurement by the measurement unit while rotating the test object;
A second step of calculating the position of the paraxial curvature center of one test surface of the test object from the measurement data acquired in the first step;
A third step of calculating a movement amount of the centering unit based on the position data calculated in the second step and the design data of the test object;
A fourth step of calculating a rotation amount of the test object based on the position data calculated in the second step and the design data of the test object;
A fifth step of setting the adjustment direction position by rotating the test object;
A sixth step of detecting that the centering unit is in contact with the object;
A seventh step of moving the position of the paraxial curvature center of one test surface of the test object by the centering unit;
A centering method comprising the steps of:   13. The centering method according to claim 12, wherein the position data of the test object used in the third step is a measurement value obtained by another measuring apparatus.   13. The centering method according to claim 12, wherein a movement amount of the position of the paraxial curvature center in the seventh step is smaller than a movement amount of the centering unit calculated in the third step. .   The movement amount of the paraxial curvature center position in the seventh step is smaller than the movement amount of the centering unit calculated in the third step by a certain amount. Centering method.   The movement amount of the position of the paraxial center of curvature in the seventh step is smaller than the movement amount of the centering unit calculated in the third step by a certain rate. Centering method. In the seventh step, after the centering unit moves the position of the paraxial curvature center of one of the test surfaces of the test object, a step of obtaining a distance between the position of the paraxial curvature center and the target position is provided. And
When the obtained distance is greater than or equal to a preset value, an adjustment amount is calculated from the distance, the adjustment is performed again by the centering unit, and the centering is repeated until the distance becomes less than a set value. The centering method according to any one of claims 12 to 16.   Based on the fact that the paraxial curvature center position of one test surface of the test object has moved in the seventh step, the measurement unit detects that the centering unit has contacted the test object. The centering method according to claim 11, wherein the centering method is performed.

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