JP6492702B2 - Optical element measuring apparatus and measuring method - Google Patents

Description

  The present invention relates to a measuring device and a measuring method for a minute thin plate-like optical element, and more particularly to a measuring device and a measuring method suitable for a thin compound eye optical system in which aspheric optical surfaces are arranged in a lattice shape.

In order to hold an optical element to be measured with high accuracy and perform eccentricity measurement, a method is known in which a spherical surface portion of a sphere serving as an outer shape reference is directly pressed against an outer edge portion of the optical element (Patent Document 1). ). In this method, since the spherical surface portion of the sphere serving as the outer shape reference is urged against the object to be measured, the outer shape can be measured with high accuracy by measuring the sphere as the outer shape reference. Further, by performing the same measurement while inverting the entire jig while keeping the outer shape reference, the highly accurate eccentric measurement can be performed. The measuring instrument is intended for a three-dimensional shape measuring instrument that measures the displacement of the stylus after directly contacting the stylus.
Moreover, in order to measure the surface shape without causing deformation on the surface of the thin plate shape, a method of making the measurement object self-standing in the vertical direction is known (Patent Document 2). In this method, the measuring instrument is an optical interference method, a laser reflection method, or the like, and a three-dimensional shape measuring instrument using a stylus is not intended.

  The former method disclosed in Patent Document 1 is applicable not only to three-dimensional shape measurement using a stylus, but also to measurement using an optical interference method, laser reflection method, etc. Since the outer shape reference device is urged and pressed against the object, the thin plate shape may cause deformation on the surface.

  As for the method described in the former Patent Document 2, since the thin plate is supported in a state where it is vertically freestanding, the thin plate in this state can be measured by the optical interference method. In the case of a three-dimensional shape measuring method using a stylus, neither of the two surfaces can be measured.

JP 2011-232348 A JP 2008-275468 A

  The present invention has been made in view of the above-mentioned problems of the background art. Even if it is a thin plate, the shape of both surfaces of a measurement object is measured by a three-dimensional shape measurement using a stylus or the like without causing deformation of the surface. It is an object of the present invention to provide an optical element measuring apparatus and measuring method that enable measurement.

  In order to achieve the above object, the optical element measuring apparatus according to the present invention supports the measuring object from the second surface side opposite to the first surface in order to expose the first surface of the measuring object and arrange it on the front side. A substrate having two support protrusions and an observation hole formed so as to overlap at least a part of the region surrounded by the three support protrusions so that measurement from the back side to the second surface side is possible. An urging member that urges the measurement object from the first surface side to the substrate side at a load generation position facing the three support protrusions across the measurement object with respect to the support direction of the measurement object, It is possible to abut on the side of the object to be measured while being movable in the direction perpendicular to the support direction on the front side, and to move in the direction perpendicular to the support direction by the frictional force generated by the pressing force in the support direction. Side support member that is suppressed And a non-holding mechanism.

  In the measurement apparatus, the biasing member fixed to the substrate biases the measurement target from the first surface side to the substrate side at the load generation position facing the three support protrusions across the measurement target with respect to the support direction. Further, it is possible to prevent a local rotational force from being applied to the measurement target, and to reduce stress that causes deformation such as bending generated in the measurement target. In addition, the side support member can be brought into contact with the side portion of the object to be measured while being movable in a direction perpendicular to the support direction on the front side of the substrate, and by the frictional force generated by receiving the pressing force in the support direction. Since the movement in the direction perpendicular to the support direction is suppressed, the measurement object should be held so as not to move in the direction perpendicular to the support direction on the front side of the substrate with little load applied to the side of the measurement object. Can do. Thereby, not only can the measurement object be supported or held in a stable state in the support direction or the lateral direction, but also the occurrence of distortion due to the support can be reduced, and the shape of the measurement object can be measured from the front and back with high accuracy.

  According to a specific aspect of the present invention, in the measurement apparatus, when the support protrusion is a truncated cone, the urging member is point-supported or line-supported so as to face each of the three support protrusions across the measurement target. Including three biasing projections that enable the surface support, and one or more members that enable surface support when the support projection is hemispherical. In this case, the support in the form of a point or short line segment and the surface support are combined to enable stable support at a plurality of locations.

  According to another aspect of the present invention, the three support protrusions are arranged to form an isosceles triangle or an equilateral triangle. In this case, the measurement object can be stably supported at three points.

  According to still another aspect of the present invention, the side support member holds or maintains the support state by friction between the supported surface of the side support member and the flat surface of the substrate. In this case, the frictional resistance against the movement of the side support member can be set only by adjusting the pressure applied between the supported surface and the flat surface, and the measurement object support direction is suppressed while suppressing the influence on the measurement object. It is possible to reliably prevent movement in a direction perpendicular to.

According to still another aspect of the present invention, the side support member is configured to move the slider in contact with the side surface of the measurement target from a direction substantially perpendicular to the measurement target, and the slider to move in the direction of moving back and forth on the measurement target. And a ball plunger provided along with the guide and biasing the slider in a direction perpendicular to the axial direction of the slider . In this case, the holding mechanism can be configured by a small and simple mechanism.

  According to yet another aspect of the present invention, the measurement object has an outer shape having a side of 5 mm or more and 15 mm or less and a thickness of 1 mm or less, and is formed of glass or plastic resin. It is a system. Such a thin compound eye optical system is sensitive to external force, and it is necessary to reduce the external force as much as possible. By using the biasing member and the holding mechanism as described above, distortion due to the external force is generated. This makes it possible to measure with high accuracy.

  According to still another aspect of the present invention, the urging member has a plate spring that urges the measurement target toward the substrate side, and the pressing force in the support direction by the plate spring is changed from the support point of the plate spring to the load point. Is set based on the distance up to, the Young's modulus of the leaf spring, the sectional moment of inertia of the leaf spring, and the amount of deflection of the leaf spring.

According to still another aspect of the present invention, the surface roughness Ra of the pair of surfaces facing each other in the contact region between the side support member and the substrate side member supporting the side support member is as follows: 0.4 μm ≦ Ra ≦ 1.6μm
Meet. In this case, the movement of the side support member in the direction perpendicular to the support direction can be easily suppressed for a light measurement target such as a thin compound eye optical system, and the measurement target can be reliably held.

  According to still another aspect of the present invention, the pressing force applied to the side support member in the support direction is 5N or less.

  In order to achieve the above object, an optical element measurement method according to the present invention measures three support protrusions that support a measurement object from the second surface side opposite to the first surface of the measurement object, and a support direction of the measurement object. Using a biasing member that biases the measurement target from the first surface side to the substrate side at the load generation position facing the three support protrusions across the target, the measurement target is supported in the support direction on the front side of the substrate, It is possible to contact the side of the measurement object while being movable in the direction perpendicular to the support direction on the front side of the substrate, and in the direction perpendicular to the support direction by the frictional force generated by the pressing force in the support direction. The measurement object is supported in the direction perpendicular to the support direction on the front side of the substrate using the side support member in which the movement of the substrate is suppressed.

  In the measurement method, the measurement object is urged from the first surface side to the substrate side by the urging member at the load generation position facing the three support protrusions across the measurement object with respect to the support direction. A local rotational force can be prevented from being applied, and the stress generated in the measurement object can be reduced. In addition, the side support member that can contact the side of the object to be measured while being movable in the direction perpendicular to the support direction is perpendicular to the support direction due to the frictional force generated by the pressing force in the support direction. Therefore, the measurement object can be held so as not to move in the direction perpendicular to the support direction on the front side of the substrate in a state where a load is hardly applied to the side portion of the measurement object. Thereby, not only can the measurement object be supported or held in a stable state in the support direction or the lateral direction, but also the occurrence of distortion due to the support can be reduced, and the shape of the measurement object can be measured from the front and back with high accuracy.

(A) And (B) is the front view and side view explaining a measuring apparatus. It is a top view explaining the jig for measurement set to a measuring device. FIG. 3 is a rear view of the measuring jig shown in FIG. 2. It is a partial expansion perspective view explaining the board | substrate center part among the jigs for a measurement shown in FIG. (A) And (B) is the top view and sectional drawing explaining a measuring object. It is a perspective view explaining the biasing member fixed to the board | substrate center part shown in FIG. It is a partial expanded sectional view explaining the support of the measuring object by a supporting member and a biasing member. It is a perspective view explaining the holding mechanism provided in the outer side of a biasing member in a board | substrate. FIG. 9 is a side sectional view for explaining the holding mechanism of FIG. 8.

  Hereinafter, a measurement apparatus and method according to an embodiment of the present invention will be specifically described with reference to the drawings.

FIGS. 1A and 1B are front and side conceptual views illustrating the structure of a measuring apparatus 200 equipped with a measuring jig 10 to be described in detail later.
This measuring apparatus 200 is a three-dimensional shape measuring apparatus using a stylus, and can measure a large number of optical surface shapes constituting a lens array that is a measurement object WO by using the measuring jig 10. The measuring device 200 has a structure in which an XY stage device 82 and a Z driving device 84 are fixed on a surface plate 81. The operations of the XY stage device 82 and the Z drive device 84 are controlled by the control device 99.

  The XY stage device 82 operates by being driven by a driving mechanism that is not described, and the measurement jig 10 placed on the placement table 89 fixed to the upper portion of the XY stage device 82 is moved in the horizontal XY plane. It can be smoothly moved to an arbitrary position in dimension. The position of the measuring jig 10 is detected using an X mirror 83a and a Y mirror 83b provided on the mounting table 82. That is, the position of the mounting table 82 in the X-axis direction can be determined by using the laser interferometer 83d mounted on the surface plate 81 so as to face the X mirror 83a. Further, the position of the mounting table 82 in the Y-axis direction can be determined by using a laser interferometer 83e mounted on the surface plate 81 so as to face the Y mirror 83b.

  The Z drive device 84 has a lifting mechanism 86 fixed on a frame 85. The lifting mechanism 86 is fixed to the upper part of the frame 85 and extends in the Z direction, and is supported by the support shaft 86a to be in the Z axis direction. Elevating member 86b that moves up and down, elevating drive means (not shown) that elevates and lowers elevating member 86b, stylus holding portion 86d supported by elevating member 86b, and touch supported by elevating member holding portion 86d so that it can be raised and lowered A needle PR.

  In the elevating mechanism 86, the elevating member 86b is supported by the support shaft 86a in a non-contact manner and smoothly moves up and down. The stylus holding portion 86d holds the stylus PR and moves up and down smoothly along with this. As for the stylus PR, a raising / lowering drive means (not shown) is operated by applying feedback so that the tip can be raised and lowered smoothly with high accuracy in a state where a constant load is applied to the tip. As a result, the whole or a plurality of local regions on the measurement target WO placed on the measurement jig 10 by appropriately operating the XY stage device 82 while raising and lowering the stylus PR with a low load are two-dimensionally displayed. If it is moved so as to scan, the tip of the stylus PR can be moved two-dimensionally along a number of optical surfaces provided on the measuring object WO placed on the measuring jig 10. At this time, the tip position of the stylus PR is detected by using a Z mirror 91a provided at the upper end of a member that moves up and down together with the stylus PR. That is, the position of the lower end of the stylus PR in the Z-axis direction can be determined by using the laser interferometer 91b mounted on the frame 85 so as to face the Z mirror 91a.

With reference to FIG.2 and FIG.3, the structure of the jig | tool 10 for a measurement installed on the mounting base 89 of the measuring apparatus 200 shown to FIG. 1 (A) etc. is demonstrated.
The measuring jig 10 includes a substrate 20, an urging device 30 that is an integral member, a holding mechanism 40 that includes a plurality of independent portions, and a reference portion 50 that includes a plurality of independent portions. Here, the urging device 30, the holding mechanism 40, and the reference portion 50 are fixed to the surface 20 a side of the substrate 20. The measuring jig 10 supports the measuring object WO in the center on the front side and can be turned upside down. That is, when the measuring jig 10 is placed with the surface 20a facing upward as shown in the drawing, a plurality of optical surfaces formed on the first surface 1a of the measuring object WO can be measured, and the measuring jig 10 is inverted. By making the back surface 20b up, it is possible to measure a plurality of optical surfaces formed on the second surface 1b of the measurement object WO.

  The substrate 20 shown in FIGS. 2 to 4 is a metal plate-like body, and is disposed at the center of the support frame 21 having a rectangular (including square) outline that matches the entire outline. And a support member 22. The support member 22 is fixed so as to be fitted into a through hole 21 a provided in the center of the support frame 21.

  Of the substrate 20, the support member 22 is formed with a substantially rectangular observation hole 22 a as a whole so that the measurement object WO supported on the support member 22 can be observed from the front and back sides. Around the observation hole 22a, three support projecting portions 22c are formed as portions protruding toward the inside of the observation hole 22a. A frustoconical support base or a support protrusion 22 d that protrudes in the normal direction from the surface 20 a side of the substrate 20 is formed on each support protrusion 22 c. The three support protrusions 22d are arranged at the apex positions of an equilateral triangle or an isosceles triangle, and support the outer peripheral portion 2f of the measurement target WO from the back second surface 1b side with three points in a balanced manner. Here, the support direction of the measurement object WO by the substrate 20 or the support protrusion 22d is the z direction perpendicular to the surface 20a of the substrate 20. Two notches 22b are formed in the observation hole 22a. These notches 22b allow a support ball 62 described later to be measured from the front and back.

  5A and 5B are a plan view and a cross-sectional view illustrating an example of the measurement object WO supported on the substrate 20 in the measurement jig 10 shown in FIG. The measurement object WO is a lens array having a rectangular plate-shaped outer shape, that is, a thin-plate compound eye optical system, and a plurality of single eyes arranged two-dimensionally in the α direction and the β direction perpendicular to the optical axis OA extending in the γ direction. A lens 2a is provided. The measurement object WO is made of plastic resin, and has a side of about 5 to 15 mm and a thickness of 1 mm or less. In the case of a small and thin measuring object WO like this lens array, bending deformation or the like occurs with a slight external force, and therefore, it is necessary to pay close attention when supporting it on the measuring jig 10. The lens array of the measurement object WO is not limited to plastic resin but may be glass.

In the illustrated example, the number of single-lens lenses 2a constituting the lens array of the measurement object WO is 16 corresponding to 4 × 4 lattice points. Each individual lens 2a in the measuring object WO is integrally molded in a connected state. In other words, the measurement object WO is an array of a large number of single-lens lenses 2a each having a lens body 2c and a flange 2d as a set, and the flanges 2d of the adjacent single-lens 2a are integrally molded. Has been. A portion obtained by combining all the flange portions 2d serves as a support body 2g that supports the lens body portion 2c. The support 2g has a flat plate shape and extends parallel to an αβ plane perpendicular to the optical axis OA parallel to the γ direction. The lens body 2c has a first optical surface 2i that is a convex aspheric surface on the object side, that is, the first surface 1a side, and a second optical surface that is a concave aspheric surface on the image side, that is, the second surface 1b side. It has surface 2j. Both optical surfaces 2i and 2j are aspherical surfaces, but may be spherical surfaces. The flange portion 2d has a flat first flange surface 2m around the first optical surface 2i, and a flat second flange surface 2n around the second optical surface 2j. The first and second flange surfaces 2m and 2n are surfaces other than the lens effective surface, and are arranged in parallel to the αβ surface. The outer peripheral part 2f of the measuring object WO is a part supported by the measuring jig 10 shown in FIG. The outer peripheral portion 2f has four side surfaces 2t used for positioning and one frame bottom surface 2u, and the four side surfaces 2t extend in parallel to the αγ surface or βγ surface as side portions of the measurement object WO. .
When the measurement object WO is attached to the measurement jig 10 shown in FIG. 2, the αβγ axis of the measurement object WO is aligned with the xyz axis of the measurement jig 10 using the side surface 2t and the frame bottom surface 2u of the measurement object WO. It is installed so as to be substantially parallel.

  The urging device 30 shown in FIGS. 2 and 6 has an overall contour formed of an annular member 31 and is open at the center to expose the first surface 1a of the measurement object WO. The biasing device 30 is fixed in a state of surrounding the support member 22 on the surface 20a side of the substrate 20 using a plurality of attachment portions 38. The urging device 30 has a role of preventing the measurement object WO placed on the support member 22 of the substrate 20 from dropping off. For this reason, the urging device 30 sets the measurement target WO at the load generation position facing the three support protrusions 22d of the support member 22 across the measurement target WO with respect to the support direction of the measurement target WO (that is, with respect to the z direction). The first surface 1a is biased toward the substrate 20 side. Specifically, the urging device 30 has three urging members 32 extending inward. Each urging member 32 is an elongated leaf spring extending linearly, is fixed to the annular member 31 on the base side, and has a hemispherical urging protrusion 32a on the tip side.

  As shown in a partially enlarged view in FIG. 7, the urging protrusion 32a of the urging member 32 is in contact with the load generation position P1 facing the support protrusion 22d in the measurement object WO. Here, the biasing protrusion 32a and the support protrusion 22d are opposed to each other with the outer peripheral portion 2f of the measurement object WO in the z direction, and are supported so as to sandwich the measurement object WO to support the measurement object WO in the z direction. However, no rotational moment is applied to the measurement object WO. Specifically, the support protrusion 22d has a truncated cone shape, the lower end of the urging protrusion 32a is hemispherical, and the urging protrusion 32a supports the outer peripheral portion 2f of the measurement target WO in a point manner. Accordingly, it is possible to easily prevent the measurement target WO from being distorted such as bending deformation while supporting the measurement target WO at three points. Note that the biasing protrusion 32a is not limited to a hemispherical shape, and may be a short cylindrical surface. In this case, similarly to the above, it is possible to easily prevent distortion such as bending deformation from occurring in the measurement target WO.

  Returning to FIG. 2, the holding mechanism 40 includes a first holding mechanism 41 that enables positioning of the measurement object WO in the x direction, and a second holding mechanism 42 that enables positioning of the measurement object WO in the y direction. .

  The first holding mechanism 41 shown in FIGS. 2 and 4 includes a side support member 41a and a limiting member 41b. The side support member 41a includes a rod-shaped slider 45 having a support sphere 62 fixed at the tip, a guide 46 for guiding the slider 45 in the axial direction, and the slider 45 from the lateral direction perpendicular to the axial direction to the substrate 20 side. And an orthogonal urging member 47 for urging. The limiting member 41b includes a support base 58a fixed to the substrate 20 and a rod-shaped contact member 58b extending from the support base 58a along the surface 20a of the substrate 20 in the x direction. The contact member 58b has a role of adjusting the position of the measurement target WO. The contact member 58b is inserted in a through hole (not shown) formed between the substrate 20 and the annular member 31 with a gap. When the rear end of the slider 45 is lightly pressed with an appropriate force in the −x direction, the support ball 62 comes into contact with the side surface 2t of the measurement object WO, and the measurement object WO can be pressed in the −x direction. The WO moves in the −x direction until the opposite side surface 2t comes into contact with the tip 58d provided with the support ball 62 of the contact member 58b. When the pushing of the rear end of the slider 45 in the −x direction is stopped, the force or load applied to the measurement target WO by the side support member 41a is almost eliminated. However, the measurement target WO includes the side support member 41a and the limiting member. It is positioned in the x direction between 41b and is stably held in the position where it is positioned unless a large external force is applied. In the above, the support sphere 62 can be used to measure or determine the x coordinate of the side surface 2t of the measurement target WO.

  The second holding mechanism 42 includes a side support member 141a and a limiting member 141b. Each side support member 141a has a structure in which two side support members 41a of the first holding mechanism 41 described above are arranged in parallel, and two rod-shaped sliders 45 each having a support ball 62 fixed to the tip, A guide 46 that guides the slider 45 in the axial direction, and two orthogonal urging members 47 that urge the slider 45 toward the substrate 20 from a lateral direction perpendicular to the axial direction. The limiting member 141b is capable of supporting the limiting member 41b of the first holding mechanism 41 described above at two points, and includes a support base 58a fixed to the substrate 20 and a surface 20a of the substrate 20 from the support base 58a. a pair of rod-shaped contact members 58b, 58b extending in the y direction. These contact members 58b and 58b have a role of adjusting the position of the measurement object WO. When the rear ends of the pair of sliders 45 are lightly pushed in the + y direction with an appropriate force, the two support balls 62 come into contact with the side surface 2t of the measurement object WO, and the measurement object WO can be pushed in the + y direction. The measurement object WO moves in the + y direction until the opposite side surface 2t comes into contact with the tip portion 58j provided with the support balls 62 of the pair of contact members 58b and 58b. When pressing the rear ends of both sliders 45 in the + y direction is stopped, the measuring object WO is sandwiched between the side support member 141a and the limiting member 141b, and is positioned with respect to the y direction and is a central axis parallel to the z axis. The rotation posture with respect to the periphery of the lens is also adjusted, and if it is not given a large external force, it is stably held at the position where it is positioned. In the above, the support sphere 62 can be used to measure or determine the y coordinate of the side surface 2t of the measurement object WO and the tilt rotation angle around the z axis.

With reference to FIG.8 and FIG.9, the specific structure of the side support member 41a of the 1st holding mechanism 41 is demonstrated.
The side support member 41a includes a locking portion 74 in addition to the slider 45, the guide 46, and the orthogonal biasing member 47 described above. Of the side support members 41a, the slider 45 is a rod-shaped member having a support ball 62 fixed at the tip. The guide 46 includes a pair of guide members 72a and 72b for guiding the slider 45 in the axial direction. The orthogonal urging member 47 presses the slider 45 from the side perpendicular to the longitudinal direction thereof, and is applied so as to press the slider 45 against the flat surface 20 s which is the opposite portion of the surface 20 a of the substrate 20. A spring 73a is provided. The locking portion 74 supports the slider 45 from the side surface side and fixes the orthogonal biasing member 47 on the substrate 20.

The slider 45 supports the measurement object WO placed on the support member 22 of the substrate 20 in the −x direction perpendicular to the side surface 2t. The slider 45 includes a tip-side holding member 71 a that is a rod that supports the support ball 62, and a root-side sliding portion 71 b that is held in a loose fit with respect to a recess formed by the locking portion 74. The outer peripheral side surfaces (upper and lower surfaces and side surfaces) of the base side sliding portion 71b can be subjected to a surface treatment such as DLC in order to improve slidability and wear resistance. The root-side sliding portion 71b is formed with an elongated hole 71f in order to guide its movement in cooperation with the locking portion 74, and the inner surface of the groove 71f is also slidable and resistant. In order to improve the wearability, a surface treatment such as DLC can be performed.
The support sphere 62 supported by the slider 45 is formed of a material having high hardness, such as ruby, silicon nitride, or cemented carbide. The support sphere 62 is a relatively small sphere having a diameter of about 0.33 to 2 mm.

  Each of the pair of guide members 72a and 72b has a cylindrical outer shape, is a guide pin that is fixed to the substrate 20 and protrudes from the surface 20a, and is arranged in the x direction in which the slider 45 extends. The pair of guide members 72a and 72b is slidably fitted in a slot 71f formed in the bottom surface of the base side sliding portion 71b and extending in the x direction. That is, the root side sliding portion 71b is supported by the surface 20a of the substrate 20 and is restricted from moving in the −z direction, and is guided by the pair of guide members 72a and 72b and the locking portion 74 to allow movement in the x direction. Is done.

  The orthogonal urging member 47 is fixed so as to be screwed and embedded in the upper portion of the locking portion 74. The lower end of the orthogonal urging member 47 abuts on the upper surface of the base side sliding portion 71b of the slider 45 and urges the base side sliding portion 71b to the flat surface 20s of the opposing substrate 20, and the state of the slider 45 The holding allows the slider 45 to slide precisely and stably. The orthogonal urging member 47 generates a desired urging force or pressing force at the tip portion by the compression force of the spring 73a. Since the tip of the orthogonal urging member 47 contacts the side surface of the slider 45 so as to slide, a ball or roller that rolls smoothly is provided at the contact portion of the tip of the orthogonal urging member 47. That is, the orthogonal urging member 47 is configured by a ball plunger.

  The slider 45 is fixed by the guide members 72a and 72b and the orthogonal urging member 47 as described above so that the position in the longitudinal direction, that is, the ± x direction can be adjusted, and the support ball 62 appropriately adjusts the side surface 2t of the measurement object WO. It is possible to adjust the position where it is pressed or abutted against this. That is, the slider 45 is weakly locked on the substrate 20 by the orthogonal urging member 47, and if no external force is applied, the flat surface 20s of the substrate 20 and the lower surface that is the supported surface of the root side sliding portion 71b. The position in the ± x direction on the substrate 20 is maintained by the frictional force generated by the pressure contact with 71k. On the other hand, when an external force in the ± x direction is applied to the slider 45, when the external force exceeds the frictional force between the surface 20a of the substrate 20 and the lower surface (supported surface) 71k of the root side sliding portion 71b, the slider 45 Moves in the ± x direction according to the external force against the frictional force, and the position in the ± x direction changes.

  Since the structure of the side support member 141a of the second holding mechanism 42 is the same as that of the first holding mechanism 41, the description thereof is omitted.

  As a result, the four side surfaces 2t of the measurement object WO are a surface supported by one support sphere 62 of the side support member 41a, a surface supported by the two support spheres 62 of the side support member 141a, and a limiting member. The surface supported by one support sphere 62 of 41b and the surface supported by the two support spheres 62 of the limiting member 141b are arranged side by side. That is, the measurement object WO is held from the periphery at an equal location.

  Returning to FIG. 2 and the like, the reference portion 50 includes three reference spheres 51 and three sphere holding portions 52. The reference sphere 51 is held in a stable state by the sphere holder 52 and is fixed to the substrate 20 via the sphere holder 52. At this time, the three reference spheres 51 are arranged at the vertex positions of an equilateral triangle having the center of gravity of the measurement object WO placed on the substrate 20 as a center of gravity, and one side of the equilateral triangle is parallel to the x direction. After being set in the measuring apparatus 200, the X axis or the Y axis corresponding to the horizontal drive axis of the measuring apparatus 200 is set. The sphere holding part 52 has a pair of openings 52a so that the reference sphere 51 can be observed from the front surface 20a side and the back surface 20b side of the substrate 20. The reference sphere 51 is formed of a high hardness material, for example, a material such as ruby, silicon nitride, or cemented carbide. The reference sphere 51 is relatively large and is a true sphere having a diameter of about 3 to 10 mm.

  When setting the measuring object WO on the measuring jig 10, first, the urging device 30 is removed from the substrate 20, and the slider 45 of the first and second holding mechanisms 41, 42 is moved backward to support the supporting member 22 of the substrate 20. Free up the space above. Thereafter, the measurement object WO is placed at an appropriate position on the support member 22, the three sliders 45 constituting the first and second holding mechanisms 41 and 42 are advanced, and the side surface 2t of the measurement object WO is lightly pressed. Thereby, the measuring object WO is positioned on the support member 22. Next, the urging device 30 is fixed to the surface 20a side of the substrate 20 by screwing or the like. Thereby, the urging protrusions 32a of the three urging members 32 urge the outer peripheral portion 2f of the measurement object WO downward, and the three support protrusions 22d that are directly opposed to the urging protrusions 32a have the outer peripheral portion 2f of the measurement object WO at the same location. Will receive. After that, the slider 45 is lightly pushed again to advance, so that the positioning of the measurement object WO in the lateral direction becomes more reliable.

  Hereinafter, a method for measuring an optical element using the measuring apparatus 200 shown in FIG. 1 and the measuring jig 10 shown in FIG. 2 will be described.

  First, the measurement jig 10 that supports the lens array (optical element) that is the measurement target WO is set on a mounting table 89 that is attached in advance to the measurement apparatus 200. At this time, the surface 20a of the substrate 20 can be observed from above. Next, by measuring the surface shapes of the three reference spheres 51 arranged on the periphery of the substrate 20, a coordinate system (front side coordinate system) corresponding to the spherical cores is determined. At this time, the coordinates of these spherical cores are measured by measuring the surface shapes of the three support spheres 62 arranged around the lens array which is the measurement target WO, and information regarding the arrangement of the side surface 2t of the measurement target WO is obtained. Can be obtained. Next, the surface shapes of the plurality of first optical surfaces 2i are sequentially measured among the surface 20a of the lens array that is the measurement object WO. At this time, if the surface 20a of the lens array has a shape as a positioning reference, the reference shape can be measured. The first optical surface 2i is measured in a two-dimensional manner by operating the XY stage device 82 in a state where the stylus PR is disposed above the first optical surface 2i and moving the stylus PR to the first optical surface 2i. While moving the scanning, the Z driving device 84 is operated to move the tip of the stylus PR so as not to leave the first optical surface 2i. Thereby, two-dimensional surface shape data is obtained. The same applies to the measurement of reference shapes other than the plurality of first optical surfaces 2i. In addition, if the 1st surface 1a of the measuring object WO is smooth, the some 1st optical surface 2i etc. can also be measured collectively.

  Next, it is set again on the mounting table 89 in an inverted state by being inverted to the measuring jig 10. In other words, the back surface 20b of the substrate 20 can be observed from above. Next, by measuring the surface shapes of the three reference spheres 51 arranged in the peripheral part of the substrate 20, a coordinate system (back side coordinate system) corresponding to the spherical cores is determined. Next, the relationship between the front-side coordinate system and the back-side coordinate system is compared with the coordinate system (front-side coordinate system) of the sphere core obtained before inversion and the coordinate system (back-side coordinate system) of the sphere core obtained after inversion. Is calculated. At this time, the coordinates of these spherical cores are measured by measuring the surface shapes of the three support spheres 62 arranged around the lens array which is the measurement target WO, and information regarding the arrangement of the side surface 2t of the measurement target WO is obtained. It can be obtained additionally. Next, among the back surface 20b of the lens array that is the measurement target WO, the surface shapes of the plurality of second optical surfaces 2j are sequentially measured. At this time, if the rear surface 20b of the lens array has a shape that serves as a positioning reference, the reference shape can be measured. Next, the first optical surface 2i and the second optical surface 2j can be directly compared by performing coordinate conversion with respect to the shape information of the surface shape of the plurality of second optical surfaces 2j with reference to the surface 20a of the lens array. To do. As a result, the amount of eccentricity can be determined by fitting the pair of first optical surface 2i and second optical surface 2j facing each other. Further, the eccentricity of the optical axis AX can be determined for a plurality of lens main bodies 2c having a pair of opposing first optical surface 2i and second optical surface 2j.

  In the measurement apparatus 200 of the embodiment described above, the orthogonal biasing member 47 fixed to the substrate 20 is the load generation position P1 that faces the three support protrusions 22d across the measurement object WO with respect to the z direction that is the support direction. Since the measurement object WO is biased from the first surface 1a side to the substrate 20 side, it is possible to prevent a local rotational force or the like from being applied to the measurement object WO and to reduce stress generated in the measurement object WO it can. Further, the side support members 41a and 141a can be in contact with the side surface 2t of the measurement object WO in a state in which the side support members 41a and 141a are movable in the direction perpendicular to the z direction, which is the support direction, on the surface 20a side of the substrate 20 Since the movement in the direction perpendicular to the support direction is suppressed by the frictional force generated by the pressing force in a certain z direction, the measurement target WO is placed on the substrate in a state where almost no load is applied to the side surface 2t of the measurement target WO. It can hold | maintain so that it may not move regarding the surface 20a side of 20 about the direction (specifically x direction and y direction which are horizontal directions) perpendicular | vertical to a support direction. As a result, not only can the measurement object WO be supported or held in a stable state with respect to the support direction or the lateral direction, but the occurrence of distortion due to the support can be reduced, and the shape of the measurement object WO can be measured from the front and back with high accuracy. .

Hereinafter, specific measurement conditions and measurement methods will be described. As the measuring apparatus 200 shown in FIG. 1 and the like, Panasonic UA3P, Mitutoyo Strato-Apex 574, and the like were used. The measurement object WO supported on the measurement jig 10 is a lens array having a 4 × 4 aspherical optical surface, and has a square outline with an outer side of about 12 mm and a thickness of 0.6 to 0.7 mm. The weight was about 0.1 g. Each urging member 32 provided in the urging device 30 is a leaf spring that generates a load or pressing force of 0.1 to 0.5 N. When the urging member 32 is a leaf spring, the load can be calculated from the amount of deflection of the leaf spring using the following conversion formula in order to give a target weight to the measurement object WO.
δ = pl ³ / 3EI (1)
Where δ is the amount of deflection of the leaf spring (mm), p is the load applied to the leaf spring (the load to be measured + the weight of the leaf spring) (N), l is the distance from the fulcrum to the load point (mm), E ... Young's modulus (N / mm ² ) of the material of the leaf spring, I ... Second moment of inertia (mm ⁴ ).
In particular, when the cross-sectional shape of the leaf spring is a square, the following conversion formula can be used.
δ = 4 pl ³ / Ebt × (1−ν ² ) (2)
Here, b: plate width (mm), t: plate thickness (mm), ν: Poisson's ratio.
For the side support members 41a and 141a, the surface roughness Ra of the contact area between the surface 20a of the substrate 20 and the lower surface 71k of the slider 45 is set to 0.4 μm ≦ Ra ≦ 1.6 μm. The side surface of the slider 45 is not in contact with the inner surface of the locking portion 74, but when contacting the inner surface of the locking portion 74, the surface roughness Ra of these contact areas is also 0.4 μm ≦ Ra ≦ 1. 6 μm. Further, the load or pressing force F applied to the slider 45 by the ball plunger which is the orthogonal urging member 47 was set to about 1.0N ≦ F ≦ 5.0N.
Under the conditions as described above, the optical surface shape and the like of the lens array were measured using the measuring apparatus 200, and the results were fed back to the mold fabrication. That is, shape correction was performed from the shape measured by the measuring apparatus 200, and improvement in lens performance was confirmed. As a result of measuring the planar portion of the lens array by white interference, the difference in the amount of distortion generated on the first surface 1a is 0 from the target value between when the measurement object WO is not restrained and when it is restrained by a jig. It was within 1 μm.

  Although the measurement apparatus and the measurement method have been described above according to the embodiment, the measurement apparatus and the measurement method of the present invention are not limited to those exemplified above, and various modifications can be made. The measuring apparatus 200 is not limited to a three-dimensional shape measuring apparatus using a stylus, and can be an apparatus using an optical interference method. In this case, for example, the surface roughness of the flat surface portion, the undulation of the entire flat surface portion, and the like are measured. Useful in some cases. The measuring device 200 is not limited to a three-dimensional shape measuring device using a stylus, and may be a device using a laser reflection method, specifically, a laser displacement meter, a shape measuring device, or the like.

  In the above embodiment, the support protrusion 22d of the support member 22 has a truncated cone shape, and the biasing protrusion 32a of the biasing member 32 has a hemispherical shape. However, the support protrusion 22d of the support member 22 has a hemispherical shape, and the biasing member 32 has a hemispherical shape. The urging protrusion 32a can be formed into a truncated cone shape.

  The front end 58j of the abutting member 58b constituting the restricting members 41b and 141b is not limited to the one provided with the support ball 62, but can be a semicircular shape that can easily realize point contact, and has a more accurate tolerance. When is high, it can be linear or planar. Also in this case, if the lateral width of the contact member 58b is narrow, the deterioration in accuracy is not particularly large.

  The urging device 30 is not limited to one in which the three urging members 32 are assembled and fixed together on a common support such as the annular member 31, and the urging members 32 are individually fixed to the substrate 20. It may be a thing.

  The structure of the side support member 41a shown in FIGS. 8 and 9 is merely an example, and various modifications and alternatives are possible. For example, the guide members 72a and 72b may be omitted, and the base side sliding portion 71b may be pressed against the inner surface of the locking portion 74 from the lateral direction by a ball plunger.

  The support member 22 and the biasing device 30 of the substrate 20 can be exchanged according to the size and contour shape of the measurement object WO.

  The observation hole 22a formed in the support member 22 of the substrate 20 is not limited to a rectangular shape, and may have various shapes surrounded by the three support protrusions 22d or the support overhang portions 22c.

  DESCRIPTION OF SYMBOLS 1a ... 1st surface, 1b ... 2nd surface, 2a ... Individual lens, 2c ... Lens main-body part, 2f ... Outer peripheral part, 2i, 2j ... Optical surface, 2t ... Side surface, 10 ... Jig for measurement, 20 ... Board | substrate, 20a ... front surface, 20b ... back surface, 21 ... support frame, 22 ... support member, 22a ... observation hole, 22c ... support overhang, 22d ... support projection, 30 ... biasing device, 31 ... annular member, 32 ... biasing 32a ... biasing protrusion, 40 ... holding mechanism, 41, 42 ... holding mechanism, 41a, 141a ... side support member, 41b, 141b ... limiting member, 45 ... slider, 46 ... guide, 47 ... orthogonal biasing member 50 ... Reference part, 51 ... Reference sphere, 52 ... Sphere holding part, 58b ... Abutting member, 58j ... Tip part, 62 ... Supporting ball, 71a ... Tip side holding member, 71b ... Root side sliding part, 71f ... groove, 71k ... lower surface, 72a, 72b ... guide member, 74 ... locking part, 82 ... XY stage device, 84 ... Z drive device, 86 ... elevating mechanism, 86d ... stylus holding part, 99 ... control device, 200 ... measuring device OA: Optical axis, PR: Stylus, WO: Measurement object

Claims (10)

Since the first surface of the measurement object is exposed and arranged on the front side, three support protrusions that support the measurement object from the second surface side opposite to the first surface, and measurement on the second surface side from the back side are also possible. A substrate having an observation hole formed so as to overlap with at least a part of a region surrounded by the three support protrusions,
The measurement object is urged from the first surface side to the substrate side at a load generation position that is fixed to the substrate and faces the three support protrusions with the measurement object sandwiched in the support direction of the measurement object. A biasing member;
The front side of the substrate can contact the side of the measurement object in a state of being movable in a direction perpendicular to the support direction, and in the support direction by a frictional force generated by a pressing force in the support direction. An optical element measurement device comprising: a holding mechanism including a side support member that is inhibited from moving in a vertical direction.   The urging member includes three urging protrusions that enable point support or line support so as to be opposed to the three support protrusions with the measurement target interposed therebetween when the support protrusion has a truncated cone shape, The optical element measuring apparatus according to claim 1, further comprising one or more members that enable surface support when the support protrusion is hemispherical.   The optical element measuring apparatus according to claim 1, wherein the three support protrusions are arranged to form an isosceles triangle or an equilateral triangle.   The said side support member is maintaining the support state by the friction by the press-contact of the to-be-supported surface of the said side support member, and the flat surface of the said board | substrate. The optical element measuring apparatus according to 1. The side support member includes a slider that abuts from a direction substantially perpendicular to a side surface of the measurement target, a guide that allows the slider to move in a direction that moves forward and backward with respect to the measurement target on the substrate, and the guide 5. The optical element measurement according to claim 1, further comprising a ball plunger which is provided along with and biases the slider in a direction perpendicular to an axial direction of the slider. apparatus.   The measurement object is a thin compound eye optical system having an outer shape with a side of 5 mm or more and 15 mm or less and a thickness of 1 mm or less, and formed of glass or plastic resin, and aspherical optical surfaces arranged in a lattice shape. The measuring device of the optical element as described in any one of -5.   The urging member has a plate spring that urges a measurement object toward the substrate, and the pressing force in the support direction by the plate spring is a distance from a support point of the plate spring to a load point, the plate The optical element measuring device according to any one of claims 1 to 6, wherein the optical element measuring device is set based on a Young's modulus of a spring, a cross-sectional secondary moment of the leaf spring, and a deflection amount of the leaf spring. . The surface roughness Ra of the pair of surfaces facing each other in the contact region between the side support member and the substrate side member supporting the side support member is as follows: 0.4 μm ≦ Ra ≦ 1.6 μm
The optical element measuring device according to claim 1, wherein:   The optical element measuring apparatus according to any one of claims 1 to 8, wherein a pressing force in the support direction applied to the side support member is 5N or less. Measurement target at three load projections that support the measurement target from the second surface side opposite to the first surface of the measurement target, and at the load generation position facing the three support projections with the measurement target in the support direction of the measurement target Using a biasing member that biases the first surface side toward the substrate side, and supports the measurement object on the front side of the substrate with respect to the support direction,
The front side of the substrate can contact the side of the measurement object in a state of being movable in a direction perpendicular to the support direction, and in the support direction by a frictional force generated by a pressing force in the support direction. A method for measuring an optical element, characterized in that a measurement object is supported in a direction perpendicular to the support direction on the front side of the substrate by using a side support member in which movement in a vertical direction is suppressed.

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