JP4125074B2 - Three-dimensional shape measurement method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to an optical element such as a lens and a prism and a technique for measuring the shape thereof.
[0002]
[Prior art]
When measuring the shape of optical elements such as lenses and prisms using a three-dimensional measuring machine, the position and orientation of the object to be measured can be measured using a measuring jig or a measuring instrument so that the surface to be measured can be measured. Measurement is performed in a fixed state. In addition, when performing highly accurate shape measurement, a measurement jig having a measurement standard is conventionally used.
[0003]
Here, as shown in FIG. 13, the measurement standard is the measurement jig reference marks 3 a to 3 c for defining the position of the measurement jig on the coordinate measuring machine, and the measurement object attached to the measurement jig. The measurement object attachment reference surfaces 2s to 2u for defining the position on the jig.
[0004]
In FIG. 13, by measuring the reference mark positions 3 a to 3 c on the measurement jig 2 when measuring the shape of the DUT 1, the mounting position and orientation of the measurement jig 2 body on the coordinate measuring machine are defined. . Thus, a measurement standard for the DUT 1 when performing the three-dimensional shape measurement is determined on a measurement jig installed on the three-dimensional shape measuring machine.
[0005]
Here, in the process of designing and manufacturing the measurement jig, the relative position of the measurement jig reference mark in the measurement jig and the measurement object mounting reference surface is relatively clarified, so that the three-dimensional A positional relationship from the measurement reference point set on the measuring machine to the measurement object mounting reference surface (point) provided in the measurement jig is defined.
[0006]
As a specific method for defining the relative positional relationship between the measurement jig reference mark position and the workpiece attachment reference point, for example, it is specified by measuring both reference points on the same CMM without changing the setup. The method is adopted. Furthermore, the relative positional relationship between the reference surface to be attached to the measuring jig and the measured surface 1a to be measured in the measured object 1 is defined by the design value of the measured object. These specified relative positional relationships can all be expressed as coordinate transformations, and by using this coordinate transformation, it is possible to grasp the shape of the surface to be measured as coordinate values in the desired coordinate system (reference). It is. As a result, it is possible to measure the shape of the measurement target region instructed to the CMM device control unit (not shown) on the measurement surface with high accuracy.
[0007]
Details of the setup during specific measurement will be described with reference to FIG.
[0008]
As shown in FIG. 13, the DUT 1 is in a state in which the reference surface of the DUT 1 is attached to the mounting reference surfaces 2 s to 2 u with respect to the measurement jig 2 installed (fixed) on the coordinate measuring machine. It is fixed with. In this state, the measuring probe 4 of the coordinate measuring machine first scans the reference marks 3a to 3c attached to the measuring jig as shown in the drawing, and measures the mark position as coordinate values in the measuring machine coordinate system. . The reference coordinate system on the measurement jig defined based on these three mark positions (three device coordinates) is clarified in advance as described above, and the measurement surface 1a of the measurement jig in the measurement jig is defined. The position and orientation can be expressed in this reference coordinate system. Accordingly, as described above, the reference mark is scanned with the measurement probe 4 and the mark position is measured, so that the position of the reference coordinate system on the coordinate measuring machine is known as the apparatus coordinate. Also for 1a, the surface position (orientation) can be expressed as coordinate values in the coordinate system of the coordinate measuring machine.
[0009]
Based on this surface position information (device coordinates), the measurement probe 4 scans the surface to be measured 1a, so that the measurement shape is obtained as the device coordinate values of the coordinate measuring machine. At this time, the contact type or non-contact type of the measurement probe is not limited.
[0010]
As described above, when measuring the shape of the object to be measured, the relative position of the reference point of the measurement target surface shape with respect to the reference point on the coordinate measuring machine is specified, and the measurement result output as a coordinate value in the coordinate measuring machine coordinate system Can be obtained as the shape of the surface to be measured of the object to be measured (Japanese Patent Laid-Open No. 11-14906).
[0011]
[Problems to be solved by the invention]
When performing the three-dimensional shape measurement according to the above-described conventional technique, an attachment error of the object to be measured with respect to the measurement jig always occurs in a state where the object to be measured is attached to the measurement jig.
[0012]
When performing shape evaluation on the measured shape, if the measured surface shape is known as the design value, the measured shape is fitted to the design shape using the least square method, etc., and the shape error of the measured shape with respect to the design shape is derived. Generally, such an evaluation method is adopted. At this time, the surface position and orientation of the surface to be measured are also obtained as position and orientation errors with respect to the design values. However, since there is always an attachment error of the object to be measured with respect to the measurement jig, this attachment error is included in the position / posture error calculated in the fitting process. That is, the position / posture error with respect to the design value of the object to be measured cannot be obtained with high accuracy by the conventional technique.
[0013]
Regarding the above-mentioned problem, in the case where surface shape measurement is performed on an optical element having only one optical effective surface as a surface shape measurement target, that is, a surface to be measured, in the optical element that is the object to be measured, The reason why it is difficult to obtain the attitude error with high accuracy in the prior art will be described below.
[0014]
When measuring the surface shape of only one surface using a 3D shape measuring machine for the object to be measured, as described in the prior art, the object to be measured is attached to a measuring jig having a reference mark, and three-dimensional measurement is performed. The shape is measured by setting the surface to be measured to a measurable posture on the machine. The measurement shape is measured using coordinate transformation based on the coordinate system defined by the reference mark in the measurement jig used and the positional relationship between the reference plane and the reference mark for mounting the measurement object in the measurement jig. It can be obtained as a coordinate value in a coordinate system that defines the design shape of the optically effective surface that is a surface. Thus, the measurement surface shape obtained as the point cloud data can be compared and evaluated in the same coordinate system as the design shape, and is generally evaluated by a fitting process using a least square method or the like.
[0015]
At this time, the residual obtained by subtracting the design shape from the measurement shape without performing the fitting process is simply regarded as the shape error of the object to be measured. Assuming that the object to be measured is fixed to the measuring jig in a state where there is no attachment error, it is possible to evaluate the shape to be measured with high accuracy by treating the error as a shape error with respect to the design shape.
[0016]
On the other hand, in actual shape measurement, an attachment error of the object to be measured with respect to the measuring jig always occurs. Therefore, strictly speaking, the shape error obtained by subtracting the design shape from the measurement shape includes an attachment error of the object to be measured with respect to the measurement jig. When the fitting process is performed on the measured surface shape measured in such a state, the shape obtained as the difference between the measured shape and the design shape is further allocated to the shape error and the position and inclination (posture) error. It will be. In the shape error and the position and inclination error obtained and allocated here, the difference shape between the measurement shape and the design shape before the fitting process includes an attachment error to the measurement jig. The mounting error is also calculated as the allocated error amount. That is, evaluating the shape error in the shape evaluation for the measurement result is a shape evaluation including an attachment error with respect to the measurement jig, and thus there is a problem that it is difficult to perform a highly accurate shape evaluation. .
[0017]
Similarly, in the case of performing surface shape measurement on an optical element in which a plurality of optical effective surfaces (two or more surfaces) are present in the optical element that is the object to be measured, The reason why it is difficult to obtain the position and orientation errors with high accuracy by the conventional technology will be described in the same manner.
[0018]
Similar to the case of performing three-dimensional shape measurement on an optical element having only one optical effective surface, when measuring the surface shape of an optical element having a plurality of optical effective surfaces to be measured, the above-described conventional technique is used. As shown, attach the object to be measured to the measuring jig with the reference mark, and place the object to be measured on the 3D measuring machine so that the surface to be measured can be measured. Measure. The method for obtaining the measurement shape as the coordinate value in the coordinate system defining the design shape of the optically effective surface is the same as the case where the surface shape measurement is performed on the optical element having only one optically effective surface. Further, the method of comparing and evaluating the measurement surface shape obtained as point cloud data with the design shape is the same as that in the case where surface shape measurement is performed on an optical element having only one optical effective surface (minimum 2). Fitting process using multiplication method).
[0019]
At this time, when there are a plurality of optical effective surfaces (two or more surfaces) to be measured, the method disclosed in Japanese Patent Application Laid-Open No. 2000-46543 is adopted, so It is possible to remove the mounting error of the measurement object with high accuracy.
[0020]
That is, for each measured surface shape data (point cloud data) expressed in common in the reference coordinate system defined by the reference mark attached to the measuring jig, the measured shapes of the measured multiple surfaces are simultaneously displayed. A fitting process using the least square method is performed on the design shape of the surface. This makes it possible to eliminate the mounting error of the object to be measured on the coordinate measuring machine, including the mounting error of the object to be measured to the measuring jig, and to evaluate the relative positional relationship of each surface to be measured with high accuracy. It becomes.
[0021]
In the case of an optical element having a plurality of optical effective surfaces, the surface position and orientation (optical axis position and orientation) of each effective surface are generally relative to a reference surface (reference position) formed in the optical element. It is specified as a design value. Therefore, when shape measurement evaluation is performed on a plurality of optically effective surfaces, it is necessary that the surface position and posture of each surface with respect to the reference surface in the optical element can be evaluated with high accuracy.
[0022]
However, in the measurement shape evaluation using the method based on the fitting process, it is possible to evaluate the relative positional relationship between the measurement object, that is, the measurement surface within the optical element, that is, the optical effective surface, with high accuracy. It is difficult to grasp the absolute position and posture in the object to be measured. This includes an error with respect to a design value with respect to an absolute position and orientation with respect to a reference surface formed in the entire measured object while maintaining a relative positional relationship among a plurality of measured surfaces. This is because the error is recognized as an attachment error of the object to be measured with respect to the measuring jig in the fitting process calculation, and is removed when the measurement shape evaluation of a plurality of measurement surfaces is performed.
[0023]
As described above, when there are a plurality of optical effective surfaces, the position error of each effective surface with respect to the reference surface formed in the optical element that defines the position of each effective surface is evaluated with high accuracy in the measurement shape evaluation of each effective surface. There was a problem that it was difficult to evaluate.
[0024]
Therefore, the present invention has been made in view of the above-described problems, and its purpose is to provide a highly accurate evaluation of the surface shape of an optically effective surface, which is a surface to be measured, in the shape measurement of an optical element by a three-dimensional shape measuring machine. Is to make it possible.
[0025]
Another object of the present invention is to make it possible to measure and evaluate an error with respect to the design value of the position and orientation of the optically effective surface with respect to a reference (surface or position) in the optical element with high accuracy.
[0040]
[Means for Solving the Problems]
  In order to solve the above-mentioned problems and achieve the purpose,The three-dimensional shape measuring method according to the present invention is formed in a plane continuous with the optically effective surface of the object to be measured, and a first reference whose normal line substantially coincides with the direction of the optical axis of the optically effective surface. A position of a surface, a position of a second reference surface formed in a direction orthogonal to the first reference surface, and a position of a third reference surface orthogonal to both the first and second reference surfaces. Is measured by a point coordinate measuring means, and an orthogonal triaxial coordinate system is obtained based on the measured position of each reference plane,continueThe shape of the optically effective surface of the object to be measuredPoint coordinatesMeasured by measuring means, and coordinate conversion of shape data of the optically effective surface into coordinate values of the orthogonal triaxial coordinate systemAnd calculating the shape data of the optical effective surface with respect to the reference surfaceIt is characterized by doing.
[0041]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
[0042]
First, an outline of the present embodiment will be described.
[0043]
The optical element in this embodiment is a reference for defining the surface position and orientation of the optically effective surface to be measured, and has at least a reference surface having a sufficient area to enable measurement with a three-dimensional measuring machine. 1 side.
[0044]
When performing the three-dimensional shape measurement of this optical element, it is set up in the same setup as that for measuring the optical effective surface at the time of measuring the shape of the optical effective surface to be subjected to the shape measurement evaluation, that is, installed in the three-dimensional measuring machine. The shape measurement is performed on the above-described reference surface created in the optical element without moving the optical element as the measured object with respect to the measuring machine.
[0045]
Here, it is assumed that the three-dimensional shape measuring apparatus in the present embodiment can perform the shape measurement of the optical effective surface and the reference surface measurement with the same setup.
[0046]
From the above, it is possible to measure and evaluate the surface position and posture of the optically effective surface with respect to the reference surface with higher accuracy than in the prior art.
[0047]
Furthermore, in an optical device in which the optical element of the present embodiment is incorporated as one component, when incorporating an optical element into this optical device, it is easy to incorporate with high accuracy compared to the case of incorporating an optical element provided by a conventional technique. As a result, the manufacturing cost of the optical device can be reduced.
[0048]
In the above configuration, a reference surface is first created in the optical element, and the reference surface and the optical effective surface are measured in a three-dimensional shape with the same setup, thereby improving the surface position and posture of the optical effective surface with respect to the design value. The operation that enables accurate measurement evaluation will be described.
[0049]
As described above, the optical element in the present embodiment has at least one reference surface for defining the optical effective surface position in addition to the optical effective surface. Further, the three-dimensional shape measuring apparatus in the present embodiment has means for measuring the coordinates of an arbitrary point of the object to be measured in addition to the surface shape measuring means. The point coordinate measuring means can also obtain surface shape data by obtaining point cloud data by continuously repeating the measurement by the measuring means. Further, in the three-dimensional shape measuring method in the present embodiment, the measurement of the optically effective surface shape by the surface shape measuring means and the measurement of the reference surface in the optical element by the point coordinate measuring means are carried out: Measurement is performed under the same setup without moving the optical element attached to the inside of the coordinate measuring machine (attaching / detaching the object to be measured with respect to the measuring machine).
[0050]
By combining the optical element to be measured as described above, a three-dimensional shape measuring apparatus for measuring the optical element, and the three-dimensional shape measuring method, an optical effective surface with respect to the optical element in the present embodiment When performing shape measurement, the position and orientation of the optically effective surface with respect to the reference surface created in the optical element, which has conventionally been difficult to measure with high accuracy, can also be measured with higher accuracy than before. . Details of this operation will be described below.
[0051]
That is, according to the optical element, the three-dimensional shape measuring apparatus, and the three-dimensional shape measuring method in the present embodiment, the surface shape measurement is performed on the optically effective surface that is the measurement target surface, thereby being fixed to the three-dimensional measuring machine. Surface shape data is obtained as a coordinate data group (point group data) expressed in a coordinate system (device coordinate system). Further, by measuring the reference plane with the point coordinate measuring means without changing the setup, the reference plane can be similarly acquired as the coordinate data of the apparatus coordinate system.
[0052]
Therefore, the object reference coordinate system defined by the reference plane coordinate data is obtained by performing the coordinate conversion calculation using the optical effective surface shape data and the reference plane coordinate data expressed in the same coordinate system (device coordinate system). It is possible to represent the optical effective surface shape data as a coordinate data group.
[0053]
The optical effective surface shape shown here grasps the position and orientation of the optical effective surface with respect to the reference surface with respect to the degree of freedom corresponding to the number of reference surfaces created on the optical element that is the object to be measured. Will be able to. This means that it is possible to remove an attachment error of the object to be measured with respect to the measurement jig, which has been difficult to remove by the shape measuring method using the conventional measurement jig having the reference mark.
[0054]
As described above, according to the present embodiment, by measuring the reference surface in the same setup as the optical effective surface measurement, it has been difficult to remove conventionally the position and orientation of the optical effective surface with respect to the reference surface. It is possible to remove the mounting error of the object to be measured with respect to the jig, and measurement and evaluation can be performed with high accuracy.
[0055]
Next, by creating a shape of the reference surface in the optical element, it becomes possible to improve the assembling accuracy and reduce the manufacturing cost of the optical apparatus when the optical element is incorporated into an optical apparatus configured as one component. The operation will be described.
[0056]
In the optical element according to the prior art, even when the reference surface is formed in the optical element, the position and posture of the optical effective surface with respect to the reference surface are accurately grasped from the three-dimensional shape measurement result of the optical effective surface. I can't. For this reason, when an optical element is incorporated in an optical device, it is necessary to incorporate and adjust the optically effective surface in an arrangement so as to obtain a desired optical performance in the optical device. This adjustment is provided in the optical device, for example. This was achieved by using the built-in adjustment mechanism and making adjustments while actually passing light through the built-in optical element.
[0057]
On the other hand, for adjustment when incorporating the optical element in the present embodiment into the optical apparatus, from the shape measurement result obtained by the shape measurement method using the three-dimensional shape measuring apparatus in the present embodiment for this optical element in advance, The surface position and orientation of the optically effective surface with respect to the reference surface in the optical element are clarified. Accordingly, the optical element built-in adjustment mechanism provided in the optical device is used to adjust the position of the optically effective surface and the positional deviation that are apparent, thereby allowing the optical element to be positioned in the optical device. Can be implemented without any problem. As described above, according to the present embodiment, adjustment when an optical element is incorporated into an optical device is simpler than in the prior art, and the manufacturing tact can be shortened, resulting in a reduction in manufacturing cost of the optical device.
[0058]
Hereinafter, embodiments of the present invention will be specifically described.
[0059]
(First embodiment)
FIG. 1 is a diagram for explaining an optical element according to the first embodiment, a shape measuring method for the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
[0060]
As shown in FIG. 1, the optical element 1 of the present embodiment has reference surfaces 1s, 1t, and 1u for defining the position and posture of the optical effective surface 1a in the optical element 1 in addition to the optical effective surface 1a. .
[0061]
That is, in the optical element shown in FIG. 1, the reference planes 1s to 1u are in a positional relationship orthogonal to each other. For example, the point perpendicular to the reference plane 1s to 1u is the origin, and the direction perpendicular to the reference plane 1s is the z axis. The object reference coordinate system defined by the reference planes 1s to 1u, wherein the direction of the straight line intersecting the reference planes 1s and 1u is the y-axis, and the direction orthogonal to the y-axis and the z-axis is the x-axis think of. Here, the design shape of the optically effective surface 1a can be expressed as a coordinate value of the measurement object reference coordinate system. Therefore, design values (tolerance standards) regarding the surface position and orientation of the optically effective surface 1a in the optical element 1 are determined in the measurement object reference coordinate system.
[0062]
On the other hand, a three-dimensional shape measuring apparatus (not shown) equipped with the probe 4 shown in FIG. 1 can measure the shape of the surface to be measured by scanning the probe 4 while making contact with the surface to be measured 1a. At this time, the measured surface measurement shape is obtained as coordinate data (point group data) in the coordinate measuring machine coordinate system. Further, as shown in FIG. 1, the probe 4 can measure the position information of the reference planes 1s to 1u as point coordinate data. Here, the means for measuring the point coordinates of the reference planes 1 s to 1 u may be a different reference plane measurement probe different from the probe 4. That is, the three-dimensional shape measuring apparatus according to the present embodiment includes means for measuring the surface shape of the measurement target surface (optically effective surface) 1a in FIG. 1 and point coordinate measurement for measuring the surface positions of the reference surfaces 1s to 1u. Means (not shown).
[0063]
Next, a method for deriving the measurement object reference coordinate system defined by the reference planes 1s to 1u using the point coordinate measurement means for measuring the reference plane position will be described in detail.
[0064]
First, with respect to the reference surface 1s, point measurement is performed at any three points on the reference surface 1s using a point coordinate measuring means (for example, the probe 4). From the coordinate data of the three points expressed in the three-dimensional shape measuring apparatus coordinate system obtained at this time, the plane including these three points is uniquely obtained in the apparatus coordinate system. That is, the direction of the normal vector of the plane including these three points is uniquely determined, and is set as an arbitrary axis when the measurement object reference coordinate system is an orthogonal triaxial coordinate system. For example, as shown in FIG. 1, the direction of the normal vector is defined as the z-axis direction of the measurement object reference coordinate system.
[0065]
Next, the reference plane position is measured for any one of the remaining two reference planes. For example, assume that the surface position is measured with respect to the reference surface 1t in FIG. Here, point measurement is performed on the reference plane 1t using the point coordinate measuring means at any two points on the reference plane 1t. At this time, two points are measured such that the direction vector of the straight line connecting the two arbitrary points does not coincide with the z-axis direction of the measurement object reference coordinate system. With respect to the two point coordinate data expressed in the coordinate system of the three-dimensional shape measuring apparatus obtained at this time, a straight line connecting the points projected on the plane derived by measuring three points on the reference plane 1s is uniquely determined. . The direction vector of this straight line is set as an arbitrary uniaxial direction in two axes other than the z axis whose direction is already determined in the measurement object reference coordinate system expressed as an orthogonal triaxial coordinate system.
[0066]
For example, as shown in FIG. 1, the x-axis direction of the measurement object reference coordinate system is determined in the same direction as the direction vector of the straight line. From the above, in the object mounting coordinate system defined by the three orthogonal axes, the directions of the two orthogonal axes (x, z axes) are determined, so the directions orthogonal to both axes are uniquely determined. It is set as the y-axis direction in the measured object coordinate system.
[0067]
Finally, the reference plane position is measured for the remaining reference plane. Here, with respect to the reference surface 1u shown in FIG. 1, point measurement is performed on the arbitrary point on the reference surface 1u using the point coordinate measuring means. Using the point coordinate data expressed in the coordinate system of the three-dimensional shape measuring apparatus obtained at this time, a plane that includes the same point and whose normal vector direction coincides with the x-axis direction of the measurement object reference coordinate system in FIG. 1 is uniquely determined. . Accordingly, the surface positions of the three orthogonal reference surfaces 1s, 1t, and 1u are defined in the common three-dimensional shape measuring apparatus coordinate system, and the intersection of the reference surfaces is set as the measurement object reference coordinate system origin. Can do. Therefore, in FIG. 1, the measurement object mounting coordinate system is obtained with respect to the apparatus coordinate system of the three-dimensional shape measuring apparatus. This is in agreement with the fact that a coordinate transformation from the coordinate system of the three-dimensional shape measuring apparatus to the measurement object reference coordinate system has been derived.
[0068]
As described above, according to the present embodiment, by measuring the surface position of the reference surfaces 1s to 1u of the object 1 shown in FIG. 1, the coordinate system from the three-dimensional shape measuring apparatus coordinate system to the object reference coordinate system is measured. It is possible to derive a coordinate transformation. Here, in this embodiment, as described above, the surface position measurement of the reference surfaces 1s to 1u and the optically effective surface to be measured are performed without attaching or removing the object to be measured from the three-dimensional shape measuring apparatus, that is, without changing the measurement setup. Surface shape measurement of the surface 1a is performed. Therefore, the surface shape of the optically effective surface 1a with respect to the reference surfaces 1s to 1u in the optical element 1 can be obtained as point cloud data represented by coordinate values in the measurement object reference coordinate system by performing the coordinate conversion calculation. .
[0069]
In the present embodiment, with respect to the measured shape data of the optical effective surface 1a derived here, the fitting process using the least square method or the like for the design shape of the optical effective surface 1a similarly defined in the measurement object reference coordinate system. By performing the above, the surface position and posture of the optically effective surface 1a with respect to the reference surfaces 1s to 1u can be measured with high accuracy.
[0070]
In the present embodiment, the design shape data defined in the measurement object reference coordinate system is subtracted from the measurement shape data of the optical effective surface 1a expressed in the measurement object reference coordinate system without performing the fitting process. Thus, the shape error of the optically effective surface 1a created in the optical element 1 with respect to the design shape can be derived with high accuracy.
[0071]
In addition, in 1st Embodiment shown in FIG. 1, about the surface position measuring method of the reference planes 1s-1u, it measures by the following method other than the measuring method mentioned above, and can derive a to-be-measured object reference coordinate system. Is possible.
[0072]
In the reference plane position measuring method described above, the point coordinate measuring means (probe 4) shown in FIG. 1 is used to measure the minimum point data necessary for defining an orthogonal triaxial coordinate system for each reference plane. Thus, the reference object coordinate system is derived. On the other hand, the surface shape of the reference surface can be measured as point group data by measuring a plurality of point coordinates for each reference surface 1s-1u by the point coordinate measuring means (probe 4). By performing the fitting process on the plane with respect to the reference plane measurement shape measured as the point cloud data, the plane in the three-dimensional shape measuring apparatus coordinate system and the normal vector of the plane can be derived for each reference plane.
[0073]
Here, for example, in FIG. 1, the vector orthogonal to the normal vector of the reference surface 1s and the normal vector of the reference surface 1t, that is, the direction of the vector obtained as the outer product of both normal vectors is shown in FIG. And the normal vector direction of the reference surface 1s is set as the z-axis direction of the measurement object reference coordinate system. Further, the direction perpendicular to the x and z axes of the measured object reference coordinate system that has already been obtained is set as the y axis direction. As to the object reference coordinate system origin position, the object reference coordinate system in the three-dimensional shape measuring apparatus is defined by obtaining and setting the intersections of the reference planes 1s to 1u orthogonal to each other in the same manner as described above. Is possible. In this embodiment, it is also possible to employ a method of defining the measurement object reference coordinate system by determining each reference surface shape by measuring with the point coordinate measuring means in this way.
[0074]
(Second Embodiment)
FIG. 2 is a diagram for explaining an optical element according to the second embodiment, a shape measuring method for the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
[0075]
In the first embodiment, the probe 4 that is a means for measuring the shape of the surface to be measured in the three-dimensional shape measuring apparatus shown in FIG. 1 scans the optical effective surface 1a that is the surface to be measured as described above. The shape of the surface to be measured can be measured by scanning while contacting the surface to be measured.
[0076]
On the other hand, in the second embodiment of the present invention shown in FIG. 2, when scanning the optically effective surface 1a, which is the surface to be measured, the surface to be measured while scanning the probe 5 without contact with the surface to be measured. The shape can be measured.
[0077]
That is, the three-dimensional shape measuring apparatus of the present embodiment may be a measuring machine equipped with a non-contact type probe as the surface shape measuring means of the optically effective surface that is the surface to be measured. In this case, the three-dimensional shape measuring apparatus is provided with both a non-contact type probe 5 for measuring a surface shape to be measured and a contact type point coordinate measuring means (probe) 4. At this time, the point coordinate measuring means 4 for measuring the reference surface position shown in FIG. 2, a reference surface measuring method using the measuring means, and a measurement object reference coordinate system deriving method derived from the reference surface measurement result The same as in the first embodiment described above.
[0078]
(Third and fourth embodiments)
3 and 4 are diagrams for explaining an optical element according to the third and fourth embodiments, a shape measuring method of the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement. .
[0079]
As shown in FIGS. 3 and 4, the optical elements of the third and fourth embodiments are at least one surface for defining the position and posture of the optical effective surface 1a in the optical element 1 in addition to the optical effective surface 1a. The reference plane 1s. That is, in the optical element 1 shown in FIGS. 3 and 4, the reference surface 1s has a normal direction of the reference surface 1s substantially coincident with the optical axis direction of the optical effective surface 1a, and the normal direction of the reference surface 1s is the same. The z axis, the two axes that are included in the reference plane 1s and are orthogonal to each other are the x axis and the y axis, respectively, and the point that is included in the reference plane 1s is the origin. Consider the object reference coordinate system.
[0080]
Here, the design shape of the optical effective surface 1a can be expressed as a coordinate value of the measurement object reference coordinate system. Therefore, design values (tolerance standards) regarding the surface position and orientation of the optically effective surface 1a in the optical element 1 are determined in the measurement object reference coordinate system. However, in this embodiment, since there is only one reference surface for defining the measurement object reference coordinate system with respect to the optical effective surface, the surface position and orientation of up to four degrees of freedom depending on the optical effective surface shape. Only the design value is determined. That is, in FIG. 3, the same three-dimensional shape measuring apparatus and measuring method as those in the first and second embodiments are used for the position in the z-axis direction of the measurement object reference coordinate system and the posture around each of the x, y, and z axes. By doing so, highly accurate measurement shape evaluation becomes possible.
[0081]
As the third embodiment of the present invention, the case where the optical element 1 shown in FIG. 3 is measured by the contact type probe 4 as the surface shape measuring means of the optically effective surface, and the fourth embodiment is shown in FIG. In the present invention, the same effect can be obtained with either method.
[0082]
(Fifth and sixth embodiments)
5 and 6 are diagrams for explaining an optical element according to the fifth and sixth embodiments, a shape measuring method for the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement. .
[0083]
As shown in FIGS. 5 and 6, the optical elements of the fifth and sixth embodiments are used as reference surfaces for defining the position and orientation of the optical effective surface 1a in the optical element 1 in addition to the optical effective surface 1a. A reference surface 1s existing in a plane in which the optical axis direction of the optical effective surface 1a and the normal direction substantially coincide with each other, and a reference formed in a direction sandwiching the optical effective surface 1a and perpendicular to the reference surface 1s. Surface 1t.
[0084]
That is, in the optical element 1 shown in FIGS. 5 and 6, the normal direction of the reference plane 1s is taken as the z-axis, the direction of the straight line intersecting the reference planes 1s and 1t is taken as the x-axis, and perpendicular to the x-axis and z-axis. Consider an object reference coordinate system defined by reference surfaces 1s and 1t, in which the direction is the y-axis and an arbitrary point on the intersection line of reference surfaces 1s and 1t is the origin.
[0085]
Here, the design shape of the optical effective surface 1a can be expressed as a coordinate value of the measurement object reference coordinate system. Therefore, design values (tolerance standards) regarding the surface position and orientation of the optically effective surface 1a in the optical element 1 are determined in the measurement object reference coordinate system. However, in the present embodiment, only the reference surfaces 1s and 1t exist for the optical effective surface 1a in FIG. 5 as the reference surface for defining the object reference coordinate system. Thus, only the surface position and orientation of five degrees of freedom are determined as design values. That is, in FIG. 5, the same three-dimensional shape measuring apparatus and measuring method as those in the first to fourth embodiments with respect to the position in the y- and z-axis directions and the postures around the x, y, and z axes of the measurement object reference coordinate system. By using, highly accurate measurement shape evaluation becomes possible.
[0086]
That is, according to the present embodiment, regarding the degree of freedom other than the position in the x-axis direction of the measurement target reference coordinate system, the surface position and orientation of the optical effective surface that is the measurement target with respect to the measurement target reference coordinate system are high. Accurate measurement evaluation is possible.
[0087]
As the fifth embodiment of the present invention, the case where the optical element 1 shown in FIG. 5 is measured by the contact type probe 4 as the surface shape measuring means of the optically effective surface, and the sixth embodiment is shown in FIG. The case of performing measurement with the non-contact type probe 5 shown in FIG. 6 can be mentioned. In the present invention, the same effect can be obtained by either method.
[0088]
(Seventh and eighth embodiments)
7 and 8 are diagrams for explaining an optical element according to the seventh and eighth embodiments, a shape measuring method for the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement. .
[0089]
As shown in FIGS. 7 and 8, the optical elements of the seventh and eighth embodiments have a plurality of optical effective surfaces 1a and 1b, and the positions of the optical effective surfaces 1a and 1b in the optical element 1, respectively. And reference surfaces 1s, 1t, and 1u for defining the posture. That is, in the optical element 1 shown in FIG. 7, the reference surfaces 1s to 1u are in a relationship in which the respective reference surfaces are orthogonal to each other as in the optical elements of the first and second embodiments of the present invention, and are defined by the reference surfaces. The measured object reference coordinate system can be set similarly to the first and second embodiments of the present invention.
[0090]
Furthermore, the design shapes of the optical effective surfaces 1a and 1b are represented as coordinate values of the measurement object reference coordinate system, and design values (tolerance standards) regarding the surface positions and postures of the optical effective surfaces 1a and 1b in the optical element 1 are obtained. The points defined in the measurement object reference coordinate system are also the same as those in the first and second embodiments.
[0091]
Here, also in an optical element having a plurality of optically effective surfaces in the optical element 1 as in the embodiment shown in FIGS. 7 and 8, the same three-dimensional shape measuring apparatus as in the first to sixth embodiments described above and By using the shape measuring method, it is possible to measure the surface position and orientation with respect to the measured object reference coordinate system with high accuracy for each of the optically effective surfaces 1a and 1b.
[0092]
That is, when measuring a plurality of optically effective surface shapes using a surface shape measuring means (contact probe 4 or non-contact probe 5), the optical element 1 that is the object to be measured is measured from the three-dimensional shape measuring apparatus. The reference plane position information is measured with respect to the reference planes 1s to 1u using the reference plane measurement point coordinate measurement means (the probe 4 or a dedicated measurement means not shown) mounted on the measurement apparatus without attaching or detaching the reference plane. Thus, in FIG. 7, the surface shape data of each of the optically effective surfaces 1a and 1b can be obtained together as the coordinate values of the measurement object reference coordinate system defined by the reference surfaces 1s to 1u.
[0093]
Here, with respect to a plurality of optical effective surface shape data expressed in the same coordinate system (measurement object reference coordinate system), a fitting process using a least square method or the like is simultaneously performed on the design shape of each surface ( The method disclosed in JP 2000-46543 is adopted). Thus, the overall position of both optical effective surfaces with respect to the reference surfaces 1s to 1u in a state where the optical effective surfaces 1a and 1b defined as design values in the optical element 1 maintain the relative positional relationship between them. In addition, it is possible to measure and evaluate the posture deviation with high accuracy.
[0094]
As the seventh embodiment of the present invention, the case where the optical element 1 shown in FIG. 7 is measured by the contact type probe 4 as the surface shape measuring means of the optical effective surface, and the eighth embodiment is shown in FIG. The case of performing measurement with the non-contact type probe 5 shown in FIG. 8 can be mentioned. In the present invention, the same effect can be obtained with either method.
[0095]
(Ninth and Tenth Embodiments)
9 and 10 are diagrams for explaining the optical element according to the ninth and tenth embodiments, the shape measuring method of the optical element, and the three-dimensional shape measuring apparatus for realizing the shape measurement. .
[0096]
As shown in FIG. 9, the optical elements of the ninth and tenth embodiments have a plurality of optical effective surfaces 1 a and 1 b, and in addition, the positions and postures of the optical effective surfaces 1 a and 1 b in the optical element 1. As a reference surface for defining, a reference surface 1s that exists in a plane in which the optical axis direction of the optically effective surfaces 1a and 1b substantially coincides with a normal direction, and a direction that sandwiches the optically effective surfaces 1a and 1b, And a reference surface 1t formed in a direction orthogonal to the surface 1s.
[0097]
Here, in the optical element 1 shown in FIGS. 9 and 10, the measurement object reference coordinate system defined by the reference surfaces 1s and 1t can be set in the same manner as the optical elements of the fifth and sixth embodiments of the present invention. It is. Furthermore, the design shapes of the optical effective surfaces 1a and 1b are represented as coordinate values of the measurement object reference coordinate system, and design values (tolerance standards) regarding the surface positions and postures of the optical effective surfaces 1a and 1b in the optical element 1 are obtained. The points defined in the measurement object reference coordinate system are also the same as those in the first and sixth embodiments.
[0098]
Here, also for the embodiment shown in FIGS. 9 and 10, the same three-dimensional shape measuring apparatus as in the first to eighth embodiments and the same shape measuring method as in the seventh and eighth embodiments are adopted. Thus, it is possible to measure the surface position and orientation of the optically effective surfaces 1a and 1b with respect to the measured object reference coordinate system with high accuracy.
[0099]
That is, according to the present embodiment, with respect to the degree of freedom other than the position in the x-axis direction of the measurement object reference coordinate system, the surface position and the optical effective surface that is the measurement surface with respect to the measurement object reference coordinate system are determined as follows. It is possible to measure and evaluate the posture with high accuracy. In addition, by performing the fitting process described in the seventh and eighth embodiments, the overall position and posture deviation of both the optically effective surfaces 1a and 1b with respect to the reference surfaces 1s and 1t can be also accurately determined. Measurement evaluation is possible.
[0100]
As the ninth embodiment of the present invention, the case where the optical element 1 shown in FIG. 9 is measured by the contact type probe 4 as the surface shape measuring means of the optical effective surface, and the tenth embodiment is shown in FIG. In the present invention, the same effect can be obtained with either method.
[0101]
(Eleventh and twelfth embodiments)
Finally, eleventh and twelfth embodiments of the present invention will be described with reference to FIGS.
[0102]
11 and 12 are diagrams for explaining the optical element molding die and the shape measuring method according to the eleventh and twelfth embodiments.
[0103]
As shown in FIGS. 11 and 12, the molds according to the eleventh and twelfth embodiments include a reference plane for defining the position and posture of the optical effective surface 1a in the illustrated mold in addition to the optical effective surface 1a. 1s, 1t, 1u.
[0104]
At this time, by using the three-dimensional shape measuring apparatus and the shape measuring method according to the first and second embodiments described above, the same effect as when the object to be measured is an optical element can be obtained. It can also be obtained in the case of a molding die.
[0105]
That is, in FIG. 11 and FIG. 12, the shape, surface position, and posture of the optically effective surface 1a with respect to the mold reference surfaces 1s, 1t, 1u can be measured and evaluated with higher accuracy than in the prior art. This is because when the optical element is molded using the mold, the surface position and orientation of the optically effective surface with respect to the reference surface are required with high accuracy. It is possible to create a built-in state in which the position and orientation of the optical effective surface 1a with respect to the reference surface are corrected in positioning, and as a result, a shape with less position and orientation errors of the optical effective surface with respect to the design shape can be obtained.
[0106]
Also in this case, as an eleventh embodiment of the present invention, FIG. 11 shows a case where measurement is performed with a contact type probe 4 as a surface shape measuring means of the optically effective surface 1a on the mold, and a twelfth embodiment. A case where measurement is performed with the non-contact type probe 5 shown in FIG. 12 can be mentioned. In the present invention, the same effect can be obtained with either method.
[0107]
The embodiment of the present invention shown in FIGS. 1 to 12 is a contact-type or non-contact-type probe in which the surface shape measuring means of the optically effective surface, which is the surface to be measured, is mounted on a three-dimensional shape measuring apparatus. There is a measurement surface shape measurement method for measuring the surface shape by scanning the probe with respect to the optical effective surface. In the present invention, the measurement surface (optical effective surface) shape measurement means is an interferometer method. There may be. In this case, the measurement time of the optical effective surface shape can be shortened as compared with the probe method.
[0108]
Further, as described above, the optical element of the embodiment of the present invention shown in FIGS. 1 to 10 is required with high accuracy with respect to the surface position and orientation of the optically effective surface with respect to the reference surface formed in the optical element. . Therefore, when the optical element is incorporated into an optical device (not shown) configured as one component, the optical element incorporation adjustment mechanism provided in the optical device is used to clarify the position and posture deviation of the optically effective surface. By adjusting the amount, the positioning of the optical element in the optical device can be performed without actually passing light.
[0109]
As described above, the optical element of each embodiment of the present invention can be easily adjusted when incorporated in an optical device, shortening the optical device manufacturing tact, and as a result, reducing the manufacturing cost of the optical device.
[0110]
The optical element of each embodiment of the present invention can be attached to various optical devices having the adjustment mechanism, such as a semiconductor exposure device, a semiconductor measurement device, an imaging camera, a laser beam printer, and a copying machine.
[0111]
【The invention's effect】
As described above, according to the present invention, in measuring the shape of an optical element using a three-dimensional shape measuring machine, it is possible to evaluate the surface shape of the optical effective surface, which is the surface to be measured, with high accuracy.
[0112]
In addition, an error with respect to the design value of the position and orientation of the optical effective surface with respect to the reference (surface or position) in the optical element can be measured and evaluated with high accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining an optical element according to a first embodiment, a method for measuring the shape of the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
FIG. 2 is a diagram for explaining an optical element according to a second embodiment, a shape measuring method for the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
FIG. 3 is a diagram for explaining an optical element according to a third embodiment, a shape measuring method for the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
FIG. 4 is a diagram for explaining an optical element according to a fourth embodiment, a shape measuring method for the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
FIG. 5 is a diagram for explaining an optical element according to a fifth embodiment, a shape measuring method of the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
FIG. 6 is a diagram for explaining an optical element according to a sixth embodiment, a shape measuring method of the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
FIG. 7 is a diagram for explaining an optical element according to a seventh embodiment, a shape measuring method for the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
FIG. 8 is a diagram for explaining an optical element according to an eighth embodiment, a shape measuring method for the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
FIG. 9 is a diagram for explaining an optical element according to a ninth embodiment, a method for measuring the shape of the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
FIG. 10 is a diagram for explaining an optical element according to a tenth embodiment, a shape measuring method for the optical element, and a three-dimensional shape measuring apparatus for realizing the shape measurement.
FIG. 11 is a view for explaining an optical element molding die and a method for measuring the shape of the die according to an eleventh embodiment.
FIG. 12 is a view for explaining an optical element molding die and a shape measuring method of the die according to a twelfth embodiment.
FIG. 13 is a diagram for explaining an object to be measured, a measuring jig for fixing the object to be measured, and a method for measuring the object to be measured in the prior art.
[Explanation of symbols]
1 Optical element (object to be measured)
1a Optical effective surface
1s, 1t, 1u Optical element (object to be measured) reference plane
2 Measuring jig
2s, 2t, 2u Measuring jig reference plane
3a, 3b, 3c Measuring jig reference mark
4 Contact probe
5 Non-contact type probe

Claims (3)

A position of a first reference surface which is formed in a surface continuous with the optical effective surface of the object to be measured, and whose normal direction substantially coincides with the direction of the optical axis of the optical effective surface; and the first reference surface Measuring the position of the second reference plane formed in the direction orthogonal to the first reference plane and the position of the third reference plane orthogonal to both the first and second reference planes by means of point coordinate measuring means, An orthogonal triaxial coordinate system is obtained based on the position of each measured reference surface, and subsequently the shape of the optical effective surface of the object to be measured is measured by the point coordinate measuring means, and the shape data of the optical effective surface is obtained as the shape data. A three-dimensional shape measuring method , wherein coordinate data is converted into coordinate values of an orthogonal three-axis coordinate system, and shape data of the optical effective surface with respect to the reference surface is calculated . The orthogonal triaxial coordinate system is
The direction of a direction vector with respect to a plane including three different points on the first reference plane is a first coordinate axis,
The direction of a direction vector of a straight line connecting points obtained by projecting two different coordinates on the second reference plane onto a plane including the three points is defined as a second coordinate axis.
The coordinate of one point on the third reference plane is measured, and the direction of a vector including that point and orthogonal to both the first coordinate axis and the second coordinate axis is defined as the third coordinate axis.
The three-dimensional shape measuring method according to claim 1, wherein the three-dimensional shape measuring method is determined. The three-dimensional shape measuring method according to claim 1, wherein there are a plurality of optically effective surfaces.

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