JP3919317B2 - Optical element shape measurement method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical element used in a video camera, a still video camera, a copying machine, and the like, and more particularly to a method for measuring the shape of an optical element having a plurality of reflective surfaces having a curvature.
[0002]
[Prior art]
In recent years, as multimedia has penetrated society, not only voice and text information but also image information data has been handled. At this time, a video camera or a digital camera is generally widely used for capturing an image. Recently, a small camera as a photographing means has also been incorporated in portable terminal devices such as mobile phones and handy computers, and it has become possible to transmit image data captured immediately after photographing using a telephone line. ing.
[0003]
The camera section of these image input devices is generally composed of a single focus lens group or a zoom lens group composed of a coaxial lens suitable for each image sensor size. These lens groups have been manufactured by processing glass in the past, but in recent years, plastic molds and glass molds are being replaced with the advancement of molding technology, thereby reducing the cost of the camera unit. Yes.
[0004]
The molding accuracy required for molding this lens group requires several micrometers, and when measuring the shape of the lens unit, attach the lens unit to the lens holding jig as shown in FIG. In general, the measurement is performed by a three-dimensional measuring instrument.
[0005]
10A and 10B are diagrams showing a shape measurement state of a conventional optical element (lens). FIG. 10A is a schematic diagram for measuring the convex side of the lens 103, and FIG. FIG.
[0006]
In FIG. 10, reference numeral 101 denotes a holding jig for holding a lens. The lens holding structure is a structure used for a general lens barrel, and the lens 103 is prevented from falling off the holding jig 101. The pressing portion 102 (a) of the holding jig 101 is pressed by a holding ring 102 that is screwed into the holding portion 101.
[0007]
Also, the surface accuracy and parallelism of the A surface and B surface of the holding jig 101 are polished to several μm or less, and the lens shape is measured even when the lens holding jig body 101 is inverted as shown in the figure. It is processed with high accuracy in a range that does not hinder the operation.
[0008]
Next, the measurement operation will be described.
[0009]
As shown in FIG. 10A, first, the shape of the lens 103 is measured by bringing one side of the lens 103 into contact with the contact 104 of the three-dimensional measuring instrument, and then the holding treatment is performed as shown in FIG. 10B. The shape of the concave surface side is similarly measured by reversing the tool 101.
[0010]
In the case of a coaxial lens, the center of the optical axis can be obtained by measuring the shape because it has a point-symmetric shape with respect to the optical axis of the lens. Therefore, the relative positional relationship between the both surfaces (uneven surfaces) can be determined relatively easily, and a high-precision lens can be molded by correcting the mold based on the result.
[0011]
[Problems to be solved by the invention]
Recently, there has been an increasing demand for miniaturization of portable terminal devices as described above, and a reflective surface having a plurality of curvatures is formed integrally on an optical element, and desired optical characteristics are obtained using reflection. Development of such non-coaxial lenses is also underway, and optical elements disclosed in, for example, Japanese Patent Application Laid-Open No. 8-292372 are being studied. Such an optical element has the advantages that the diameter of the front lens can be made smaller and thinner in the thickness direction than a coaxial lens, and rapid development / research is being promoted as a promising technology in the future.
[0012]
However, in such an optical element, since many free-form surfaces are formed in each direction, a very advanced technique is required as a molding and measurement technique, and there are still problems from the viewpoint of mass production of optical elements. is doing. In particular, since the free-form surface is configured in each direction, the method of measuring a conventional coaxial lens has a complicated shape of the holding jig for measuring the shape of each free-form surface of the optical element. It was not possible to obtain sufficient accuracy when reversing the holding jig.
[0013]
Therefore, in order to accumulate mold correction data, measures were taken to improve the reliability by increasing the number of lens shape measurements, but it took a lot of time and effort, leading to an increase in mold costs, and low costs. It was difficult to provide a lens. In addition, since the shape of the holding jig is complicated as described above, there is a problem that the cost of the lens increases due to an increase in manufacturing cost.
[0014]
The present invention has been made to solve the above-described problems. In a non-coaxial lens in which a plurality of reflecting surfaces are integrally formed, it is possible to easily and accurately measure the lens shape. An object of the present invention is to provide a shape measuring method capable of obtaining a highly accurate lens at low cost.
[0015]
[Means for Solving the Problems]
The present invention is a method for measuring the shape of an optical element having the following configuration.
[0016]
According to a first aspect of the present invention, there is provided a method for measuring a shape of an optical element, comprising: a refracting surface on which a light beam is incident on a transparent body; a plurality of reflecting surfaces having a curvature; An optical element integrally formed with the surface;
An optical element holding means for holding the optical element,
In the optical element holding means The shape measurement reference portions are formed at least at three places, and the plane including the optical reference axis of the optical element is not parallel to the plane defined by the at least three shape measurement reference portions. The shape measurement standard part is arranged, By measuring the shape measurement reference portion, an absolute coordinate system of the optical element is defined, and the refractive surface and the reflective surface are measured.
[0017]
The invention of claim 2 is characterized in that, in the invention of claim 1, the shape measurement reference portion is formed in a spherical shape.
[0018]
According to a third aspect of the present invention, there is provided a method for measuring a shape of an optical element, comprising: a refracting surface on which a light beam is incident on a transparent body; a plurality of reflecting surfaces having a curvature; An optical element integrally formed with the surface;
In the optical element The shape measurement reference portions are formed at least at three places, and the plane including the optical reference axis of the optical element is not parallel to the plane defined by the at least three shape measurement reference portions. The shape measurement standard part is arranged. By measuring the shape measurement reference part, the absolute coordinate system of the optical element is defined, and the refractive surface and the reflective surface are measured.
[0019]
According to a fourth aspect of the present invention, in the third aspect of the present invention, the shape measurement reference portion is formed in a spherical shape.
[0020]
According to a fifth aspect of the present invention, in the fourth aspect of the invention, the shape measurement reference portion is integrally formed with the optical element by insert molding.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
[0026]
Embodiment 1 FIG.
FIG. 1 is an optical path cross-sectional view showing an example of an optical element as an object to be measured in the shape measuring method of the present invention. In FIG. 1, 1 is an example of an optical element in which a plurality of reflecting surfaces having a curvature are integrally formed. The optical element 1 is a convex lens R1, a plane mirror R2, a concave mirror R3, a convex mirror R4, and a concave mirror R5 in order from the object side. Convex mirror R6, concave mirror R7, and concave lens R8.
[0027]
The reflection surface is indicated by a hatched portion in the drawing, and the plane mirror R2 is configured to incline the optical reference axis by 90 degrees as will be described later. However, in the optical path sectional view, it is in the same plane as the optical reference axis 5 (b). It is arranged.
[0028]
Here, as shown in the perspective view of FIG. 2, the convex lens R1 includes concave and convex surface mirrors R3 to R7, which will be described later, and a concave lens. R8 The optical reference axis 5 (b) is inclined 90 degrees (perpendicular) by the plane mirror R2. Reference numeral 2 denotes an optical correction plate provided on both sides of the infrared cut filter 2a with crystal low-pass filters 2b and 2c for generating birefringence in the horizontal and vertical directions, 3 denotes an image pickup element surface such as a CCD, and 4 denotes an optical element 1. 5 is an optical reference axis of the photographic optical system, 5 (a) is the convex lens R1, the optical reference axis of the plane mirror R2, and 5 (b) is the concave / convex surface mirrors R3 to R7 and the concave lens R8. The optical reference axes are orthogonal to each other as shown in FIG.
[0029]
Next, an image forming operation in the optical element will be described. Light 6 from an object (not shown) is incident on the convex lens R1 of the optical element 1 after the amount of incident light is regulated by the diaphragm 4. The object beam 6 incident on the convex lens R1 is then reflected by the plane mirror R2, bent 90 degrees, and reaches the concave mirror R3. The object light 6 reflected by the concave mirror R3 primarily forms an object image on the intermediate imaging plane N1 by the power of the convex lens R1. Thus, by forming an object image in the optical element 1 at an early stage, an increase in the effective beam diameter of the surface disposed on the imaging side from the stop 4 is suppressed.
[0030]
The object light 6 primarily imaged on the intermediate imaging surface N1 is reflected and refracted by the convex mirror R4, concave mirror R5, convex mirror R6, concave mirror R7, and concave lens R8, and depends on the power of each concave and convex surface mirror and concave lens. The object light 6 is imaged on the image sensor surface 3 while being influenced.
[0031]
As described above, the optical element 1 functions as a lens unit having desired optical performance and positive power as a whole while repeating reflection by a plurality of concave and convex surface mirrors having refraction and curvature at the entrance and exit positions.
[0032]
FIG. 2 is a perspective view of the optical element 1 as an object to be measured as viewed from each direction, and FIG. 2A is a perspective view of the incident surface and the reflecting surfaces of the concave mirrors R3, R5, and R7 as viewed from the direction. 2B is a perspective view seen from the direction in which the entrance surface and the reflecting surfaces of the convex mirrors R4 and R6 can be observed, and FIG. 2C is a view from the direction in which the plane mirror R2 that bends the exit surface and the object light 6 by 90 degrees can be observed. FIG.
[0033]
The optical element 1 shown in FIGS. 2 (a), 2 (b), and 2 (c) is formed by molding, the inside of the optical path is filled with resin, and the dry film is formed on each reflecting surface. A reflective film made of aluminum or silver is formed by vapor deposition, sputtering, or plating, which is a wet film formation method. Also, the refractive lens surface on the entrance and exit surfaces is made of SiO. ₂ And MgF ₂ A permeable film (antireflection film) is formed to improve the transmission efficiency.
[0034]
In terms of shape, the entire optical element 1 has an arcuate shape, and a flange 7 is provided as a shape measurement reference surface of the entire optical element 1 in the vicinity of the concave lens R8 surface on the exit surface side of the optical element 1. . The flange portion 7 has a plane portion 7 (c) parallel to a plane including the optical reference axis 5 (b) and a plane portion 7 (a), 7 (b), 7 (d) perpendicular to the plane including the optical reference axis 5 (b). In the first embodiment, 7 (a), 7 (c), and 7 (d) out of the flat surface portions are held jigs 8 during shape measurement. ( It is a reference mounting surface for the optical element holding means). Each reference surface of the flange 7 is used not only for shape measurement but also for holding the optical element 1 in a lens barrel (not shown).
[0035]
Also, a flange 8 is formed in the vicinity of the convex lens R1 on the incident surface side, and this flange 8 is a plane perpendicular to the plane 8 (c) parallel to the plane including the optical reference axis 5 (b). In the first embodiment, 8 (a) and 8 (c) of the plane portions are attached to the holding jig when measuring the shape. It is said. This reference surface is used in the same manner as the flange portion 7 when holding the shape on a reference surface for shape measurement and a lens barrel (not shown).
[0036]
Next, although not particularly described, FIGS. 3 to 5 are views of the optical element 1 shown in FIG. 3 is a view observed from the refractive surface R1, FIG. 4 is a view observed from the concave and convex surface mirrors R4 and R6, and the concave lens R8 side, and FIG. 5 is a view observed from the concave mirrors R3, R5, and R7 side.
[0037]
Next, a shape measuring procedure for measuring the shape of the optical element 1 shown in FIG. 1 by the shape measuring method of the present invention will be described with reference to FIG.
[0038]
FIG. 6 shows a state in which the optical element 1 is attached to the holding jig 16, FIG. 6 (a) is a view seen from the direction in which the convex mirrors R4 and R6 can be observed, and FIG. 6 (b) can see the convex lens R1. FIG. 6C is a view seen from the direction, and FIG. 6C is a view seen from the direction in which the optical reference axes 5 (a) and 5 (b) of the optical element 1 can be observed.
[0039]
In FIG. 6, the holding jig 16 holds the reference surfaces 7 (a), 7 (c), 7 (d), 8 (a), and 8 (c) at the time of measuring the shape of the optical element 1 described above. The jig has reference surfaces 16 (a), 16 (b), 16 (c), 16 (d), and 16 (e). Further, steel balls 17 (17 (a), 17 (b), 17 (c)) as a reference of the holding jig are attached to the outer peripheral portion of the holding jig 16 at three locations. By measuring the shape, the center position of the sphere is virtually calculated to set the reference plane and the origin of the absolute coordinate system.
[0040]
In general, three-dimensional measuring instruments are mainly used for measuring in the vertical direction while moving the contact in the horizontal direction. At this time, in order to measure each surface of the optical element 1 having a free-form surface in each direction. For this, the holding jig to which the optical element 1 is attached must be reversed so that the surface to be measured is exposed on the upper surface in the vertical direction.
[0041]
In the present invention, the concave and convex surface mirrors R3 to R7 and the concave lens R8 are exposed surfaces on which the contact can come into contact with the holding jig 16, and the holding jig 16 is provided with notches 18 and 19. In addition, the contact of the three-dimensional measuring device can come into contact with the convex lens R1 and the plane mirror R2.
[0042]
In general, a measurement reference plane is provided on a part of the outer shape of the holding jig 16, and when measuring the shape of the optical element 1, the measurement reference plane is measured by a three-dimensional measuring instrument to set the reference plane and the origin of the absolute coordinate system. However, since the mounting error due to the reversal of the holding jig 16 is slightly generated within the processing limit range, the reversal may reduce the reliability of the measurement data of each free-form surface.
[0043]
Therefore, in the first embodiment, as shown in FIG. 6, a steel ball 17 is attached to the outer peripheral portion of the holding jig 16 by adhesion or the like, and three steel balls are always three-dimensionally with respect to the surface to be measured of the optical element 1. It is arranged so that it can contact the contact of the measuring instrument. In other words, the plane including the optical reference axis of the optical element 1 is not arranged parallel to the reference plane set by three steel balls.
[0044]
At this time, when the surface to be measured is a plane, the direction perpendicular to the plane (normal direction) is determined to be one, so the positions of the three steel balls have a simple relationship. In the case of a free-form surface or a coaxial system, since there are many normal directions in the entire effective area, the position of the three steel balls is conveniently set so that the reference plane is not parallel to all normal directions. Need to be placed.
[0045]
In addition, since steel balls can be processed with a very high accuracy in sphericity and diameter in general through the polishing process, the reliability of the absolute coordinate system can be made extremely high, and the steel balls can be mass-produced. The holding jig can be manufactured at a relatively low cost, which is favorable from the viewpoint.
[0046]
Also in the first embodiment, the sphericity of the steel balls used is O.D. The one having an accuracy of 05 μm and a diameter of 1 μm is used. By doing in this way, even if the holding jig 16 is reversed or moved, the measurement reference plane and the origin of the absolute coordinate system can be set with high accuracy by always measuring three steel balls.
[0047]
In the first embodiment, in FIG. 6, the center of the steel ball 17 (a) is the origin of the absolute coordinate system, and an absolute coordinate system is set as shown in the figure. In this absolute coordinate system, the optical element 1 The relative positional relationship between each refracting surface and reflecting surface is measured.
[0048]
Next, molding processing of the optical element 1 and measurement data handling will be described.
[0049]
The optical element 1 as an object to be measured according to the present invention is processed by injection molding, and a modified PMMA having excellent optical characteristics and environmental resistance is used as a molding material. This modified PMMA is a material having a very low hygroscopic property, such as Hitachi Chemical's Optrez OZ-1000 and Mitsubishi Rayon's Acrypet WF-100. In addition, Nippon Zeon's ZEONEX480S and Mitsui Petrochemical's APEL5014DO, which are olefin-based resins, are extremely excellent in hygroscopicity and are suitable as lens materials for molds.
[0050]
Each reflecting surface of the optical element 1 is composed of a free-form surface, and its molding accuracy is required to be as high as several microns in terms of shape accuracy and sub-micron in terms of surface accuracy in the same manner as a normal coaxial lens. In order to obtain such a high molding accuracy, it is naturally necessary to perform sub-micron processing as mold processing, and higher accuracy is required as a shape measurement technique.
[0051]
Further, each free-form surface of the optical element 1 is polished because sub-micron is required as the surface accuracy as described above, and the mold is a mold for each free-form surface to improve the processability of the polishing process. The mold pieces are divided and produced.
[0052]
Therefore, when the mold is assembled, the positional deviation between the mold pieces is about several microns, and a relative inclination occurs between the reference planes forming the free-form curved surfaces. Therefore, there is a case where the mold or molded product is measured to calculate the amount of inclination of each free-form surface, and the mold is corrected.
[0053]
For measuring molds or molded products, a 3D measuring instrument with a resolution of submicron or less is used in consideration of the required surface accuracy of each free-form surface. In many cases, continuous measurement data cannot always be obtained due to dents and surface roughness.
[0054]
The term “continuous data” here means only macroscopic meaning, and since data sampling is digitally extracted during measurement, it is basically a set of point data, and is discontinuous. It is. When such a component exists, generally, it becomes a high frequency component for continuous data of a free-form surface and is included in measurement data.
[0055]
Therefore, firstly, the measurement data is passed through a low-pass filter, and the above-described unnecessary high-frequency components are removed to create purified data. Next, since the refined data is a collection of point data, it is necessary to interpolate into continuous surface data, and the refined data is interpolated using a least-two-modulus method to obtain design data (sequential The surface tilt correction amount is calculated so as to match the correct surface data. Hereinafter, this operation is referred to as fitting.
[0056]
At this time, as shown in FIG. 7, for example, when the curvature change of the free-form surface is extremely small and close to a spherical shape, the displacement amount δ is very small even when rotating around the point A which is the center of the pseudo-spherical shape. For this reason, the reliability of the tilt correction amount (angle θ) may be very low. In addition, as described above, unnecessary high-frequency components are removed from the measurement data through a low-pass filter, as described above, but low-frequency components generated by room vibrations in the measurement environment are mixed, and components that differ from actual free-form surface data May be included. Even in such a case, even if fitting is performed, tilt correction cannot be performed properly, and it becomes difficult to calculate the surface shape of the free-form surface.
[0057]
Therefore, in the present invention, as described above, the optical element 1 and the holding means 16 for holding the optical element are configured, and steel balls as shape measurement reference parts are provided at least at three locations on the outer periphery of the holding means 16. By measuring the steel ball 17, the absolute coordinate system of the optical element 1 is defined, and the refractive surface and the reflective surface of the optical element 1 are measured. Can be improved dramatically, and the above-mentioned problems can be solved and fitting can be performed with high accuracy.
[0058]
In the first embodiment, the steel ball 17 is formed on the outer peripheral portion of the holding jig 16, but the steel ball 17 is not concerned and the roundness and the absolute diameter are ensured with high accuracy. If there is no problem, for example, a material such as ceramic or glass may be used. Further, the shape does not need to be a perfect spherical shape, and even a part of the spherical shape may be a configuration that allows the contact of the three-dimensional measuring device to contact from a necessary direction.
[0059]
On the other hand, the optical element 1 as the object to be measured in the first embodiment is molded by resin injection molding, but the material as the optical element is a resin excellent in optical characteristics represented by PMMA or the like. Not only that, but glass molding using a glass material having excellent optical properties may be used.
[0060]
Embodiment 2. FIG.
8 and 9 are diagrams showing Embodiment 2 of the present invention. FIG. 8 is a perspective view of the optical element 51 as viewed from each direction, and FIG. 8A is a perspective view of the incident surface of the convex lens R1 and the reflective surfaces of the concave mirrors R3, R5, and R7 as viewed from the direction. FIG. 8B is a perspective view seen from the direction in which the incident surface of the convex lens R1 and the reflecting surfaces of the convex mirrors R4 and R6 can be observed. FIG. 8C shows the exit surface of the concave lens R8 and the plane mirror R2 that bends the object light 6 at 90 degrees. It is the perspective view seen from the direction which can be observed.
[0061]
The optical element 51 has the same free-form surface shape and position as the optical element 1 in the first embodiment, and only the shape of the collar portion is different. Therefore, the optical path cross-sectional view is the same as that shown in FIG.
[0062]
As shown in FIGS. 8A, 8B, and 8C, the entire optical element 51 has an arcuate shape, and the entire optical element 51 is located near the concave lens R8 surface on the exit surface side of the optical element 51. A collar portion 52 is provided as a shape measurement reference surface.
[0063]
The flange portion 52 has a plane portion 52 (c) parallel to the plane including the optical reference axis 5 (b) and perpendicular plane portions 52 (a) and 52 (b). A flat portion 52 (d) having two portions 53 (53 (a) and 53 (b) in the figure) is provided. In the second embodiment, the plane portion 52 (d) is inclined at 45 degrees with respect to the plane portion 52 (a) and the plane portion 52 (b). The convex portions 53 (a) and 53 (b) formed on the flat portion 52 (d) have a spherical tip, and the absolute coordinates of the optical element 51 when measuring the relative positional relationship between the refractive surface and the reflective surface. It is the standard of the system.
[0064]
Similarly, the planar portion 52 (e), which is the back side of the planar portion 52 (d), also has two spherical convex portions 53 (c) and 53 (d). The convex portions 53 (c) and 53 (d) are also used as a reference for the absolute coordinate system when measuring the relative positional relationship between the refracting surface and the reflecting surface, and the convex portions 53 (a) and 53 (b) described above. And the center positions are made to coincide with each other, the reference positions on the opposite reflecting surfaces are made to coincide, and the relative positions between the reflecting surfaces are measured.
[0065]
Further, although the shape is different from the first embodiment in the vicinity of the convex lens R1 on the incident surface side, a flange portion 54 is formed, and this flange portion 54 is parallel to a plane including the optical reference axis 5 (b). The plane portions 54 (c) and 54 (d) are perpendicular to the plane portions 54 (a) and 54 (b), and the plane portion 54 (a) has a convex portion 55 (a).
[0066]
The convex portion 55 (a) has a spherical tip as in the convex portion 53 and serves as a reference for the absolute coordinate system of the optical element 51 when measuring the relative positional relationship between the refractive surface and the reflective surface. Similarly, the flat surface portion 54 (b) on the back side of the flat surface portion 54 (a) has a spherical shape 55 (b). Similarly, the convex portion 55 (b) serves as a reference for the absolute coordinate system when measuring the relative positional relationship between the refracting surface and the reflecting surface, and the central position coincides with the convex portion 55 (a) described above. This is for measuring the relative position between the reflecting surfaces by matching the reference positions on the reflecting surfaces facing each other.
[0067]
FIG. 9 shows a state in which the optical element 51 is attached to the holding jig 56 and the shape is measured by a three-dimensional measuring instrument. FIG. 9A is a diagram observed from the reflecting surface side of the concave mirrors R3, R5, R7. FIG. 9B is a side view thereof.
[0068]
Here, basically, since the measuring method of each reflecting surface and the refracting surface is the same, the reflecting surface R5 will be described as a representative. First, the shape of the convex portion 53 (a) of the optical element 51 attached to the holding jig 56 is measured by the contact 57 of the three-dimensional measuring device to obtain the virtual center position. Next, the convex portion 53 (b) and the convex portion 53 (a) are measured in the same manner to obtain a virtual center position.
[0069]
The plane formed by the three points is set as a reference plane, and the virtual center position of the convex portion 53 (a) is set as the origin of the absolute coordinate system. With the origin of the absolute coordinate system set, the contactor 57 is moved to measure the shape of the reflecting surface R5. The absolute position of the reflecting surface R5 is measured by the above procedure. Hereinafter, similarly, each other reflecting surface and refracting surface may be measured.
[0070]
In this way, by providing a measurement reference portion (absolute coordinate system) on a part of the outer shape of the optical element 51, the shape of each reflecting surface and refracting surface can be increased without depending on the processing accuracy of the holding jig 56. It can be measured accurately.
[0071]
Further, the convex portion 53 (b) and the convex portion 53 (a), which are measurement reference portions, are integrally formed with the optical element 51 in the second embodiment, but when the optical element 51 is molded, The measurement reference part can be configured with a very simple mold configuration by insert molding in which a steel ball with high accuracy in terms of diameter accuracy is inserted.
[0072]
The material to be inserted at this time is preferably a material whose hardness is higher than the hardness of the contact 57 of the three-dimensional measuring instrument from the viewpoint of measurement reliability. Generally, a metal material is considered suitable. However, it may be a material such as glass, ceramic, or engineering plastic that has a high hardness and a softening point higher than that of the base material (low moisture absorption PMMA in the second embodiment).
[0073]
【The invention's effect】
As described above, according to the present invention, the refracting surface on which the light beam enters the transparent body, the plurality of reflecting surfaces having a curvature, and the refracting surface that emits the light beam reflected by the plurality of reflecting surfaces are integrated. Since the optical element formed in the optical element and the optical element holding means for holding the optical element are configured to measure the shape measurement reference portion formed in the optical element holding means, the absolute coordinates of the optical element The system is defined, and the relative positional relationship between the refractive surface and the reflective surface can be measured with high accuracy.
[0074]
According to the present invention, at least three shape measurement reference portions are formed, and a plane defined by the at least three shape measurement reference portions and a plane including the optical reference axis of the optical element are parallel to each other. Since the shape measurement reference part is arranged so that it does not become necessary, it becomes possible to measure all measured surfaces, and the relative positional relationship between the refracting surface and the reflecting surface can be measured with high accuracy. is there.
[0075]
In addition, according to the present invention, since the shape measurement reference portion is configured to have a spherical shape, the relative positional relationship between the refracting surface and the reflecting surface can be measured with high accuracy, and measurement can be performed with a simple configuration. There is an effect that can be performed.
[0076]
In addition, according to the present invention, since the shape measurement reference portion is made of a material having high hardness such as a steel ball, glass, ceramic, etc., there is an effect that an inexpensive measurement system having high reliability can be provided. .
[0077]
Further, according to the present invention, the refractive surface on which the light beam is incident on the transparent body, the plurality of reflecting surfaces having curvature, and the refractive surface that emits the light beam reflected by the plurality of reflecting surfaces are integrally formed. Since the optical element is configured to measure the shape measurement reference portion formed on the optical element, the absolute coordinate system of the optical element is defined and the refractive surface and the reflective surface of the optical element are measured with high accuracy. As a result, an inexpensive measurement system can be provided.
[0078]
According to the present invention, at least three shape measurement reference portions are formed, and a plane defined by the at least three shape measurement reference portions and a plane including the optical reference axis of the optical element are parallel to each other. Since the shape measurement reference part is arranged so that it does not become necessary, it becomes possible to measure all measured surfaces, and the relative positional relationship between the refracting surface and the reflecting surface can be measured with high accuracy. is there.
[0079]
In addition, according to the present invention, since the shape measurement reference portion is configured in a spherical shape, the relative positional relationship between the refractive surface and the reflective surface can be measured with high accuracy, and measurement can be performed with a simple configuration. There is an effect that can be done.
[0080]
In addition, according to the present invention, since the shape measurement reference portion is integrally formed with the optical element by insert molding, there is an effect that an inexpensive measurement system can be provided.
[0081]
In addition, according to the present invention, since the spherical insert member is made of a material having a high hardness such as a steel ball, glass, or ceramic and a high softening point, an inexpensive measurement system having high reliability is provided. There is an effect that can be done.
[0082]
As a result of the above, according to the present invention, the shape of a non-coaxial optical element in which a plurality of reflecting surfaces are integrally formed can be measured with high accuracy, and the jig relationship required for the measurement is also extremely high. It is possible to provide a simple configuration and to provide a highly accurate optical element at a low cost.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an optical path of an optical element according to Embodiment 1 of the present invention.
FIG. 2 is a perspective view of an optical element viewed from various directions.
FIG. 3 is a diagram of an optical element as viewed from the refractive surface side.
FIG. 4 is a diagram of the optical element as viewed from the concave-convex surface mirror and the concave lens side.
FIG. 5 is a view of an optical element as viewed from the concave mirror side.
6 is a schematic sectional view of an optical element attached to a holding jig and viewed from each direction in order to explain a method for measuring the shape of the optical element according to Embodiment 1 of the present invention. FIG.
FIG. 7 is a schematic explanatory diagram of curvature change.
FIG. 8 is a perspective view of an optical element according to Embodiment 2 of the present invention.
FIGS. 9A and 9B are a front view and a side view showing a state where the optical element of FIG. 8 is attached to a holding jig.
FIGS. 10A and 10B are diagrams showing a state measurement state of a conventional photoelectric element, in which FIG. 10A is a schematic diagram for measuring the convex surface side of the photoelectric element, and FIG. 10B is a schematic diagram for measuring the concave surface side of the photoelectric element; FIG.
[Explanation of symbols]
R1 Convex lens (refractive surface)
R2 plane mirror (reflective surface)
R3 concave mirror (reflective surface)
R4 Convex mirror (reflecting mirror)
R5 concave mirror (reflective surface)
R6 Convex mirror (reflection surface)
R7 concave mirror (reflective surface)
R8 concave lens (refractive surface)
1, 51 Optical element
16.56 Holding jig (optical element holding jig)
17 Steel ball (shape measurement standard part)
53 (53a, 53b) Convex part (shape measurement reference part)

Claims (5)

An optical element integrally formed with a refracting surface on which a light beam is incident on a transparent body, a plurality of reflecting surfaces having a curvature, and a refracting surface that emits a light beam reflected by the plurality of reflecting surfaces;
An optical element holding means for holding the optical element,
The optical element holding means has at least three shape measurement reference portions, and a plane including the optical reference axis of the optical element with respect to the plane defined by the at least three shape measurement reference portions. The shape measurement reference portion is arranged so as not to be parallel, and by measuring the shape measurement reference portion, the absolute coordinate system of the optical element is defined and the refractive surface and the reflection surface are measured. A method for measuring the shape of an optical element.   The method for measuring a shape of an optical element according to claim 1, wherein the shape measurement reference portion is formed in a spherical shape. An optical element integrally formed with a refracting surface on which a light beam is incident on a transparent body, a plurality of reflecting surfaces having a curvature, and a refracting surface that emits a light beam reflected by the plurality of reflecting surfaces;
The optical element has at least three shape measurement reference portions, and a plane including the optical reference axis of the optical element is parallel to a plane defined by the at least three shape measurement reference portions. An optical element characterized in that the shape measurement reference portion is arranged so as not to be defined, and the refractive coordinate surface and the reflection surface are measured by defining the absolute coordinate system of the optical element by measuring the shape measurement reference portion. Shape measurement method. 4. The optical element shape measuring method according to claim 3, wherein the shape measuring reference portion is formed in a spherical shape. The shape measurement reference portion shape measurement of an optical element according to claim 4, characterized in that integrally formed on the optical element by insert molding.

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