JP2006334767A - Manufacturing method of optical element and the optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical element and an optical element, forming a step in a boundary part 22 between two adjacent machined surfaces 21 in manufacturing an optical element or a mold by cutting. <P>SOLUTION: A machined surface 21 for forming an element surface is formed by relatively moving a milling cutter 10 and a base material 20 for forming the optical element in the cutting direction and in the feeding direction while the milling cutter 10 including a rotating shaft 11 and a blade part 12 projected in the direction intersecting the axial direction of the rotating shaft 11 is rotated around the axis of the rotating shaft 11. In the boundary part 22 of the machined surfaces 21, out of the two machined surfaces 21 adjacent to each other with the rotating shaft 11 pointing in the orthogonal direction to the boundary part 22, the lower machined surface 21 is cut. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention manufactures an optical element by cutting or grinding an optical element forming base material such as an optical material constituting an optical element or a mold material constituting a mold for molding an optical element. It is about how to do.

  Application of fly-cut ultraprecision processing machines to optical materials that make up optical elements or mold materials that make up molds for molding optical elements is being considered (for example, patents) Reference 1).

In such a fly-cut type ultra-precision processing machine, as shown in FIG. 14, a fly cutter 10 having a blade portion 12 protruding in a direction intersecting the axial direction from the rotary shaft 11 is used as a cutting tool, While rotating the rotating shaft 11 around the axis, the cutting tool and the base material 20 are moved relative to each other in the cutting direction and the feeding direction that intersect the axial direction to form the processing surface 21.
JP 2004-219494 A

  However, in recent years, as an optical element, as shown in FIG. 15A, an optical element in which a boundary portion 22 between two adjacent processed surfaces 21 is stepped is required. When manufactured by the cutting method, the region surrounded by the circle A in FIG. 15A is enlarged and shown in FIG. 15B, and the turning radius of the cutting edge of the fly cutter 10 is set at the boundary 22 of the processing surface 21. The shape has a corresponding roundness, that is, a shape with a rounded corner. For example, when the height of the step is desired to be several tens of μm, the rotation radius of the general fly cutter 10 is several mm, and blurring of several hundreds of μm occurs. In the case of an optical element, such a shape is not preferable because light incident on the boundary portion 22 is lost even if it is an ordinary mechanical part, even if it is not a big problem. Such a problem also occurs in the processing with a grinding tool in which a disc-shaped or cylindrical grindstone protrudes from the rotating shaft as a blade portion.

  In view of the above problems, an object of the present invention is to provide an optical element manufacturing method capable of forming a step at a boundary portion between two adjacent processing surfaces and an optical element when an optical element or a die is manufactured by cutting. It is to provide an element.

  In order to solve the above-mentioned problems, in the present invention, in a method of manufacturing an optical element in which a step is formed at a boundary part between adjacent element surfaces, a rotating shaft and a blade part projecting sideways from the rotating shaft are provided. While the provided tool is rotated around the axis of the rotary shaft, the tool and the base for forming the optical element are relatively moved in the cutting direction and the feeding direction to form a processing surface for forming the element surface. In addition, the boundary portion is characterized by cutting or grinding the lower processing surface side of two processing surfaces adjacent to each other with the rotation axis oriented in a direction orthogonal to the boundary portion.

  In the present invention, when machining the machining surface, the tool and the substrate are moved relative to each other to cut or grind the substrate, but when forming the boundary portion, the rotation axis of the tool is set with respect to the boundary portion. To the direction orthogonal. For this reason, the shape of the boundary portion can be controlled with high accuracy by the shape of the blade portion, and the side wall can be formed in an upright shape for the step. Therefore, in the case of an optical element, it is possible to form a step, and it is possible to avoid the light incident on the boundary region from generating loss or stray light.

  In the present invention, the tool is a fly cutter. In this case, the fly cutter is, for example, a flat fly cutter having a rectangular cutting edge when the blade portion is viewed from the feeding direction. If comprised in this way, since a boundary part can be processed by the linear side surface of a blade part, the side wall of a step part can be processed substantially perpendicularly. In the present invention, as the fly cutter, an outer round fly cutter having a circular cutting edge when the blade portion is viewed from the feeding direction may be used.

  The present invention can also be applied to the case where the tool is machined using a grinding tool in which a disc-shaped or column-shaped grindstone protrudes from the rotating shaft as the blade portion.

  The present invention can also be applied to processing the processed surface into a curved surface by continuously changing the relative position between the tool and the base material in the cutting direction.

  In the present invention, when a plurality of the processed surfaces are arranged in the circumferential direction, it is preferable to set the feed direction radially from a predetermined position on the substrate when forming the plurality of processed surfaces. With this configuration, when cutting the machining surface, the rotation axis is oriented in a direction crossing the boundary, and when cutting near the boundary, the rotation axis is orthogonal to the boundary. The feed direction is parallel to the boundary portion. Therefore, the shape of the boundary portion can be controlled with high accuracy by the shape of the blade portion. In addition, since the central region is subjected to multiple cutting, it can be finished to a smooth surface, and since this region is near the optical axis in the optical element, the characteristics of the optical element can be improved.

  In the present invention, the plurality of machining surfaces may be arranged in a circumferential direction, and when forming the plurality of machining surfaces, the feeding direction may be set in an arc shape centered on a predetermined position on the substrate.

  In this invention, it is preferable that the process by the said tool is controlled by the conditions represented by the cylindrical coordinate system. If comprised in this way, the programming in the case of a process is easier than a rectangular coordinate system.

  In the present invention, the substrate is an optical material constituting the optical element or a mold material for molding the optical element. However, when high accuracy is required for the shape of the step or the like, it is preferable to manufacture the optical element by cutting the optical material constituting the optical element as a base material.

  In the present invention, when machining the machining surface, the tool and the substrate are moved relative to each other to cut the substrate, but when forming the boundary portion, the rotation axis of the tool is orthogonal to the boundary portion. Turn in the direction you want. For this reason, the shape of the boundary portion can be controlled with high accuracy by the shape of the blade portion, and the side wall can be formed in an upright shape for the step. Therefore, in the case of an optical element, it is possible to form a step, and it is possible to avoid the light incident on the boundary region from generating loss or stray light. In the case of a flat fly cutter with a rectangular cutting edge or an equivalently shaped grinding tool, the loss of light decreases as the cutting edge width is reduced. The less light is lost. The cutting edge width of a tool having a rectangular cutting edge is preferably 20 μm or less, and more preferably 10 μm or less. When the cutting edge is a circular tool, the cutting edge R is preferably 0.2 mm or less, and more preferably 0.1 mm or less.

  Embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
FIGS. 1A and 1B are an explanatory diagram of an optical element to which the present invention is applied and a cross-sectional view of a step formed in a boundary area between processing surfaces (element surfaces) of the optical element. . FIG. 2 is an explanatory view of a flat fly cutter. FIG. 3 is an explanatory view showing a processing method (a method for manufacturing an optical element) according to Embodiment 1 of the present invention. FIG. 4 is an explanatory diagram of a cylindrical coordinate system used in the processing method of this embodiment. FIG. 5 is an explanatory diagram when the boundary portion is processed in the processing method of the present embodiment. 6 is a cross-sectional view when processing is performed by the method shown in FIG.

  In this embodiment, a fly cutter is used as a tool for projecting the blade portion from the rotation axis to the side to perform the outer periphery processing, and the base material for the optical element is cut by this fly cutter, as shown in FIG. As described above, an optical element (lens) in which four machining surfaces 21 (element surfaces) are arranged in a circumferential direction in a circular concave surface, and a boundary 22 of the four machining surfaces 21 intersects at one point. An example of manufacturing will be described.

  Here, the four processed surfaces 21 (divided lens surfaces / element surfaces) are formed with different curved surfaces, and the boundary portion 22 is stepped as shown in FIG.

  In manufacturing such an optical element, in this embodiment, an optical material such as a resin is cut into a lens shape by a fly cutter 10 (flat fly cutter) shown in FIG. The fly cutter 10 has a rectangular blade portion 12 protruding from the rotary shaft 11 in a direction perpendicular to the axis, and draws a locus on a cylindrical surface when rotated at a high speed.

  The processing machine provided with such a fly cutter 10 includes a three-axis feed mechanism indicated by arrows X, Y, and Z in FIG. 3 and a rotation mechanism indicated by arrows A, B, and C. Hereinafter, the rotation mechanisms around the X axis, the Y axis, and the Z axis indicated by arrows A, B, and C are referred to as an A axis, a B axis, and a C axis. In addition, since the process of this form should just carry out relative movement with the fly cutter 10 and the base material 20, the feed mechanism shown by the arrow X, Y, Z and the rotation mechanism shown by the arrow A, B, C are respectively fly. It is comprised in the optimal one of the cutter 10 side or the base material 20 side.

  In order to process the base material 20 with such a processing machine, first, while the fly cutter 10 is rotated around the axis as indicated by the arrow A, the Y-axis (cutting direction) is cut into the base material 20. . Further, the machining surface 21 is cut by feeding by the Z axis (feeding direction). At this time, each divided lens surface having a predetermined curved surface is created by simultaneously moving the Y axis and the Z axis.

  In this embodiment, the intersection point of the boundary portion 22 is set as the origin, the feed direction is set radially on the base material 20, the base material 20 is cut, and then the angular position in the feed direction is sequentially switched.

  In the processing program of the processing machine of the present embodiment, as shown in FIG. 4, the coordinate system is a cylindrical coordinate system (Rw, θw) with the intersection point of the boundary portion 22 as the origin and the center (optical axis) of the optical element as the reference axis. , Yw). Therefore, the processing point is Yw corresponding to Rw under the condition of constant θw.

  Under such control, after one feed to the processing surface 21 is completed, the fly cutter 10 is released from the base material 20 by Y-axis movement, and then the step is over by rotation of the B-axis to perform the above cutting. repeat.

Here, assuming that the upper limit allowable value of the surface roughness is Hmax, the maximum radius from the intersection is rmax, and the maximum inclination angle in the θw direction is φmax (> 0), the B-axis rotation pitch Bp “rad” is expressed by the following formula Bp < (Hmax) / ((rmax) * Tan (φmax)) Formula (a)
Determined by

  In such a machining method, when the machining surface 21 is cut, the direction in which the rotation axis 11 intersects the boundary portion 22 is set, and when the vicinity of the boundary portion 22 is cut, as shown in FIG. Thus, the direction of the rotation axis 11 is orthogonal to the boundary portion 22, and the Z axis (feeding direction) is parallel to the boundary portion 22. In this state, the lower processing surface 21 side of the two adjacent processing surfaces 21 is cut. At that time, as shown in FIG. 6, the corner of the step and the corner of the fly cutter 10 are aligned so that the step and the fly cutter 10 do not interfere with each other, that is, the region where the step is to be formed is not cut. Set the coordinates of the B-axis angle or X-axis position.

  Thus, in this embodiment, when the processing surface 21 is processed, the fly cutter 10 and the base material 20 are relatively moved in the cutting direction and the feeding direction to cut the base material 20, but the boundary portion 22 is processed. In this case, the rotating shaft 11 is directed in the direction orthogonal to each other, and the Z axis (feeding direction) is set in parallel with the boundary portion 22, and the lower processing surface 21 side of the two adjacent processing surfaces 21 is set. To cut. For this reason, the shape of the boundary portion 22 is the same as the shape of the blade portion 12 and can be controlled with high accuracy, so that the side wall can be formed upright with respect to the step. Therefore, in the optical element, the step can be formed with a sharp shape with no corners and the step surface almost upright, and therefore the width of the boundary portion 22 is narrow. Therefore, it is possible to prevent the light incident on the boundary portion 22 from generating loss or stray light.

  Further, in this embodiment, since the feed direction is set radially on the base material 20 around the intersection of the boundary portions 22 and the base material 20 is cut, the central region of the optical element is cut many times, Become. Here, the vicinity of the intersection of the boundary portion 22 is the optical axis center of the optical element, and since the surface accuracy of this region is high, an optical element with high optical characteristics can be manufactured.

[Embodiment 2]
FIG. 7 is an explanatory view showing a processing method (optical element manufacturing method) according to Embodiment 2 of the present invention. FIG. 8 is an explanatory diagram showing a state in which the rotating shaft 11 is tilted in the processing method of the present embodiment.

  In the method according to the first embodiment, the surface roughness Hmax tends to increase as the inclination angle φmax in the θw direction increases. In such a case, the method described below with reference to FIG. 7 is adopted. do it. In this embodiment, the fly cutter 10 shown in FIG. 2 is used as in the first embodiment. Also in this embodiment, as in the first embodiment, as shown in FIG. 7, a three-axis feed mechanism indicated by arrows X, Y, and Z is provided, and a rotation mechanism indicated by arrows A, B, and C is provided. is doing.

In this embodiment, when the allowable upper limit value of the surface roughness is Hmax and the minimum curvature radius ρmin (> 0) of the sectional curve in the θw direction, the blade width L of the fly cutter 10 is as follows: L <2 * √ (2 * (Hmax) * (ρmin) − (Hmax) ² ) Equation (b)
Select one that meets the requirements. Also in this embodiment, as in the first embodiment, the intersection point of the boundary portion 22 is set as the origin, the feed direction is set radially on the base material 20 and the base material 20 is ground, and then the angular position in the feed direction is sequentially set. Switch over. Further, as shown in FIG. 7, the base material 20 and the fly cutter 10 are arranged with the X axis inclined obliquely.

  Then, cutting is performed by moving the Y axis, and feeding is performed by moving the Z axis. At that time, the machining surface 21 formed of a curved surface is created by simultaneously moving the X axis, the Y axis, the Z axis, and the C axis.

  Here, as shown in FIG. 8, the C axis is rotated in accordance with the inclination angle of the processed shape in the θw direction. The X axis is used to correct the cutting edge deviation ΔX due to the C axis rotation. The Y axis also corrects the cutting edge deviation ΔY by rotating the C axis.

  After forming the processed surface 21 in this manner, the fly cutter 10 is released from the base material 20 by Y-axis movement, and then step-over is performed by B-axis rotation.

  Further, in the vicinity of the boundary portion 22, the rotating shaft 11 is oriented in a direction orthogonal to the boundary portion 22, and the Z axis (feeding direction) is set in parallel to the boundary portion 22, so that two adjacent machining surfaces 21 are provided. Of these, the lower processing surface 21 side is cut.

  By repeating the above, four radial processed surfaces 21 are formed, and four boundary portions 22 (steps) extending radially are formed.

  Thus, also in this embodiment, when machining the boundary portion 22 as in the first embodiment, the rotary shaft 11 is directed in the direction orthogonal to each other, and the Z axis (feeding direction) is parallel to the boundary portion 22. It sets and cuts the lower processing surface 21 side among two adjacent processing surfaces 21. For this reason, the shape of the boundary portion 22 is the same as the shape of the blade portion 12 and can be controlled with high accuracy, so that the side wall can be formed upright with respect to the step.

  Further, according to this embodiment, the B-axis rotation pitch and the surface roughness are not significantly involved, and the surface roughness is represented by the above-described formula (b). Note that the B-axis rotation pitch may be a value that can utilize the blade width L to the maximum.

[Embodiment 3]
When a shape error in the vicinity of the boundary portion 22 is allowed, as a cutting tool, as shown in FIG. 9, a fly cutter 10 (outer round fly cutter) having a circular shape of the blade portion 12 when viewed from the feeding direction may be used. Good. The fly cutter 10 has an arcuate cutting edge and draws a locus of a torus when rotated at high speed. Also when using such a round fly cutter 10, the fly cutter 10 and the base material 20 are arrange | positioned as shown in FIG.

Here, if the allowable limit value of the blur width of the boundary portion 22 is dmax and the maximum value of the step is tmax, the cutting edge curvature radius Rc of the fly cutter 10 is expressed by the following formula: Rc <((dmax) ² + (tmax) ² ) / (2 * (tmax)) Formula (c)
It is sufficient to select one that satisfies the requirements.

  In order to process the base material 20 with such a processing machine, first, while the fly cutter 10 is rotated as indicated by an arrow A, cutting is performed by movement in the Y axis (cutting direction). Further, the machining surface 21 is cut by feeding by movement in the Z axis (feeding direction). At this time, each divided lens surface having a predetermined curved surface is created by simultaneously moving the Y axis and the Z axis.

  Further, as shown in FIG. 9, the coordinates of the tool reference point in the workpiece coordinate system (X, Y, Z) so that the normal of the machining point and the normal of the point on the torus drawn by the fly cutter 10 coincide with each other. ) At that time, the X-axis is used to correct the edge deviation ΔX as described above. The Y axis also corrects the cutting edge deviation ΔY.

  After forming the processed surface 21 in this manner, the fly cutter 10 is released from the base material 20 by Y-axis movement, and then step-over is performed by B-axis rotation. Here, when the machining surface 21 is a spherical surface, the B-axis rotation pitch Bp [Bp (rad)] is determined by the following equation.

When the upper limit allowable value of the surface roughness is Hmax, the maximum radius from the intersection is rmax, the cutting edge curvature radius of the fly cutter 10 is Rc, and the spherical radius is ρ, the B-axis rotation pitch Bp is expressed by the following formula Bp <(2 / (Rmax)) * √ (2 * (Hmax) / (1 / (ρ−Rc) + 1 / Rc))
... Formula (d)
Is set to the value indicated by.

  Also in this embodiment, as in the first and second embodiments, in the vicinity of the boundary portion 22, the rotation axis 11 is directed in a direction orthogonal to the boundary portion 22, and the Z axis (feeding direction) is set to the boundary portion 22. The lower processing surface 21 side of the two adjacent processing surfaces 21 is cut.

  By repeating the above, four radial processed surfaces 21 are formed, and four boundary portions 22 (steps) extending radially are formed.

  Thus, also in this embodiment, when machining the boundary portion 22 as in the first embodiment, the rotary shaft 11 is directed in the direction orthogonal to each other, and the Z axis (feeding direction) is parallel to the boundary portion 22. It sets and cuts the lower processing surface 21 side among two adjacent processing surfaces 21. For this reason, the shape of the boundary portion 22 is the same as the shape of the blade portion 12 and can be controlled with high accuracy, so that it can be formed with a width that can ignore the circular arc attached to the step. Therefore, in the case of an optical element, it can be avoided that light incident on the boundary portion 22 generates loss or stray light.

  Further, in this embodiment, the C-axis rotation is unnecessary, and a surface having a surface roughness better than that of the first embodiment can be obtained.

[Embodiment 4]
FIG. 10 is an explanatory view showing a processing method (optical element manufacturing method) according to Embodiment 4 of the present invention.

  If the following changes are made to the first embodiment, arc-shaped cutting centering on the intersection of the boundary portions 22 as shown in FIG. 10 is possible. That is, the blade portion 12 of the fly cutter 10 at the starting point is aligned with the boundary portion 22 by the B-axis rotation. Here, when starting the cutting process on the machining surface 21 from a lower surface in the step, the rotation axis 11 is directed in a direction orthogonal to the boundary portion 22, and the corner of the step and the edge of the blade portion 12 of the fly cutter 10. The coordinates of the B-axis angle or the X-axis position are designated so that the part matches.

  Next, cutting is performed by moving the Y axis, and feeding is performed by rotating the B axis. As a result, the feed direction is set in an arc shape centered on a predetermined position on the substrate 20, so that the tool mark is formed in an arc shape. At this time, the machining surface 21 is made a curved surface by simultaneously moving the Y axis and the Z axis. In this embodiment as well, a cylindrical coordinate system (Rw, θw, Yw) with the intersection point of the boundary portion 22 as the origin and the center position of the optical element as the reference axis is considered as the coordinate system. Therefore, Yw corresponding to θw is considered under the condition that Rw is constant.

  Next, the blade portion 12 of the fly cutter 10 is aligned with the boundary portion 22 at the end point by B-axis rotation. Here, when the continuous surface shape ends with the lower step, the coordinate of the B-axis angle or the X-axis position obtained by combining the corner of the step and the corner of the fly cutter 10 is indicated.

  After the processing on one processing surface 21 is completed in this way, the fly cutter 10 is released from the base material 20 by the Y-axis movement, and then the step cutting is performed by the B-axis rotation, and the above cutting is repeated.

  Thus, also in this embodiment, when processing the processed surface 21, the fly cutter 10 and the base material 20 are relatively moved to cut the base material 20, but when the boundary portion 22 is formed, the fly cutter is used. The ten rotation shafts 11 are oriented in a direction orthogonal to the boundary portion 22. For this reason, the shape of the boundary part 22 can be controlled with high accuracy by the shape of the blade part 12, and the side wall can be formed in a shape in which the side walls are almost upright. Therefore, in the case of the optical element, the step can be formed with a sharp shape with no corners and the step surface being almost upright, and it is possible to prevent the light incident on the boundary portion 22 from generating loss or stray light.

[Other processing methods]
In the above embodiment, as shown in FIG. 1A, four machining surfaces 21 (element surfaces) are arranged in a circumferential direction in a circular concave curved surface, and a boundary portion 22 between the four machining surfaces 21 is formed. Although an example of manufacturing an optical element (lens) that intersects one point has been described, as shown in FIG. 11A, a flat processing surface 21 (element surface) is provided on one surface of a disk. The present invention may be applied to the case where an optical element (transmission / refraction type deflecting plate) in which a large number are arranged in the direction and the boundary portions 22 of the numerous processed surfaces 21 intersect at one point is manufactured. In addition, although a step is provided in FIG. 11 (a), it may be formed with an inclined surface without a step serving as a boundary portion. Further, as shown in FIG. You may apply when processing like a spherical surface. Further, the present invention may be applied to an optical element (lens) shaped as described with reference to FIG.

  Moreover, although the example which cuts optical materials, such as resin, into a lens shape with the fly cutter 10 was demonstrated in the said form, the metal material for cutting a metal material for metal mold | dies with the fly cutter 10 and shape | molding an optical element is demonstrated. You may apply this invention to manufacture of a type | mold.

  Furthermore, in the said form, although the thing provided with the rectangular blade part 12 was used as the fly cutter 10, depending on the shape of the level | step difference calculated | required, the fly cutter provided with the trapezoidal blade part 12 as shown in FIG. 10 may be used.

  Furthermore, in the present invention, instead of the fly cutter 10, as shown in FIG. 13, a grinding process using a grinding tool 10 'in which a disc-shaped or cylindrical grindstone 12' protrudes as a blade portion from a rotating shaft 11 '. You may apply to.

  Here, in the case of a flat fly cutter with a rectangular cutting edge or an equivalently shaped grinding tool, the light loss decreases as the cutting edge width is reduced. The smaller the is, the less light loss. The cutting edge width of a tool having a rectangular cutting edge is preferably 20 μm or less, and more preferably 10 μm or less. When the cutting edge is a circular tool, the cutting edge R is preferably 0.2 mm or less, and more preferably 0.1 mm or less.

(A), (b) is explanatory drawing of the optical element to which this invention is applied, respectively, and sectional drawing of the level | step difference formed in the boundary part area | region of each process surface (element surface) of this optical element. It is explanatory drawing of a flat fly cutter. It is explanatory drawing which shows the processing method (manufacturing method of an optical element) which concerns on Embodiment 1 of this invention. It is explanatory drawing of a cylindrical coordinate system. It is explanatory drawing at the time of processing a boundary part in the processing method shown in FIG. It is sectional drawing when processing by the method shown in FIG. It is explanatory drawing which shows the processing method (manufacturing method of an optical element) which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows a mode that the rotating shaft was inclined in the processing method shown in FIG. It is explanatory drawing which shows the processing method (manufacturing method of an optical element) which concerns on Embodiment 3 of this invention. It is explanatory drawing which shows the processing method (manufacturing method of an optical element) which concerns on Embodiment 4 of this invention. It is explanatory drawing of another optical element in which the boundary area | region of a process surface becomes a level | step difference. It is explanatory drawing of another flat fly cutter. It is explanatory drawing at the time of using a grinding tool as a tool in the manufacturing method of the optical element which concerns on this invention. It is explanatory drawing of a fly cut system. It is explanatory drawing which shows the problem of the conventional processing method (manufacturing method of an optical element).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fly cutter 10 'Grinding tool 11, 11' Rotating shaft 12 Blade part 12 'Grinding wheel (blade part)
20 Base material 21 Processing surface 22 Boundary part

Claims (12)

In the method of manufacturing an optical element in which a step is formed at the boundary between adjacent element surfaces,
While rotating a tool provided with a rotary shaft and a blade projecting sideways from the rotary shaft about the axis of the rotary shaft, the tool and the substrate for forming an optical element are relatively moved in a cutting direction and a feeding direction. Moving to form a working surface for forming the element surface;
In the boundary portion, the lower processing surface side of two adjacent processing surfaces facing the boundary portion in a direction orthogonal to the rotation axis is cut or ground. Production method.   The method of manufacturing an optical element according to claim 1, wherein the tool is a fly cutter.   3. The method of manufacturing an optical element according to claim 2, wherein the fly cutter is a flat fly cutter having a rectangular cutting edge when the blade portion is viewed from the feeding direction.   3. The method of manufacturing an optical element according to claim 2, wherein the fly cutter is an outer round fly cutter having a circular cutting edge when the blade portion is viewed from a feeding direction.   The method of manufacturing an optical element according to claim 1, wherein the tool is a grinding tool in which a disc-shaped or columnar grindstone protrudes from the rotating shaft as the blade portion.   6. The method of manufacturing an optical element according to claim 1, wherein the processing surface is processed into a curved surface by continuously changing a relative position between the tool and the base material in the cutting direction.   In any one of Claim 1 thru | or 6, When the said process surface is arranged in multiple numbers in the circumferential direction and forms the said some process surface, setting the said feed direction radially from the predetermined position on the said base material. A method for manufacturing an optical element.   In any one of Claim 1 thru | or 6, when the said processed surface is arranged in multiple numbers by the circumferential direction and forms the said processed surface, the said feed direction is made into the circular arc shape centering on the predetermined position on the said base material. A method for manufacturing an optical element, characterized by comprising: setting.   9. The method of manufacturing an optical element according to claim 7, wherein the processing by the tool is controlled by a condition expressed in a cylindrical coordinate system.   The method of manufacturing an optical element according to claim 1, wherein the base material is an optical material constituting the optical element.   10. The method of manufacturing an optical element according to claim 1, wherein the base material is a mold material for molding the optical element.   An optical element manufactured using the method defined in any one of claims 1 to 11.

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