JP2013160773A - Manufacturing method of diffraction optical element, and diffraction optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a diffraction optical element capable of solving the problem in which since deformation and transfer of a lens substrate for molding is restricted by an embankment, there occurs transfer failure of a diffraction grating in an optical effective part in the vicinity of the embankment, in a step of using a mold having at an end part the embankment for controlling the height of a molding to mold the diffraction optical element with an optical resin for molding.SOLUTION: In a manufacturing method of a diffraction optical element that has a step of using a mold having an embankment for controlling the height of a molding outside an optical effective diameter to transfer the shape of the mold with an optical member for molding, the diffraction optical element is manufacture using the mold that has a groove whose cross-sectional shape is formed of obtuse angles between the embankment of the mold and the outermost part of an optical effective part, or whose cross-sectional shape is formed of a smoothly curved line.

Description

  The present invention relates to a method for manufacturing a diffractive optical element used in an optical apparatus such as a camera or a video, and a diffractive optical element.

  In the manufacture of an optical element obtained by transferring the shape of a molding die with a molding optical resin, conventionally, in order to control the height of an optical element molded product, as described in Patent Document 1, a bank is provided. A mold is used. Here, the bank is formed at an end portion outside the optical effective diameter of the mold, and the height of the desired optical element molded product and the height of the bank coincide. The height of the diffraction grating molding resin is controlled by molding the molding lens substrate in contact with the bank of the molding die.

JP 2002-210755 A

  However, when the conventional example described in Patent Document 1 is used in the manufacture of a diffractive optical element, transferability deteriorates at the outermost portion in the optically effective portion near the bank of the mold, and the transfer of the diffraction grating of the diffractive optical element occurs. A problem to be solved that is defective occurs. The defective transfer of the diffraction grating means a state where the shape of the molding die is not transferred at the front end of the diffraction grating of the diffractive optical element. This transfer failure occurs when the molding optical resin is peeled off from the mold during curing due to curing shrinkage of the molding optical resin. Due to the transfer failure of the front end of the diffraction grating, the diffraction efficiency of the diffractive optical element is lowered, and the optical performance is deteriorated.

  In the step of forming the diffraction grating of the diffractive optical element, the shrinkage stress is concentrated in the resin at the tip of the diffraction grating due to curing shrinkage of the molding optical resin. Further, when the height of the molded product is controlled using a mold having a bank, the molding lens substrate on the upper part of the bank is restrained. As a result, at the outermost portion of the effective diameter near the bank, movement and deformation of the molding lens substrate are suppressed at the upper part, and the shrinkage stress in the resin at the tip of the diffraction grating becomes particularly large near the bank, and the diffraction grating Transfer defects occur.

  In order to solve the above-mentioned problem, a first invention according to the present application is a diffractive optical system including a step of transferring a shape of a molding die using a molding optical material, using a molding die having a bank outside the outer periphery of the optically effective portion. In the element manufacturing method, a molding having a groove between the bank of the mold and the outermost portion of the optically effective portion that is deeper than the deepest portion of the optically effective portion and whose cross-sectional angles are all obtuse angles. It is characterized by using a mold.

  In order to solve the above-mentioned problem, a second invention according to the present application uses a molding die having a bank outside the outer periphery of the optically effective portion, and has a step of transferring the shape of the molding die using a molding optical material. In the element manufacturing method, use a mold having a groove having a curve having a smooth cross-sectional shape between the bank of the mold and the outermost part of the optically effective part, which is deeper than the deepest part of the optically effective part. It is characterized by.

  According to the method for manufacturing a diffractive optical element according to the present invention, a diffractive optical element can be manufactured in a state in which the height of a molded product is controlled and without causing a transfer defect at the tip of the diffraction grating. An excellent diffractive optical element can be manufactured. Furthermore, since the production yield is improved by suppressing the occurrence of transfer defects, the manufacturing cost of the diffractive optical element can be reduced.

  Further, according to the diffractive optical element according to another aspect of the present invention, the transferability of the diffraction grating tip of the diffractive optical element is stable, so that the optical performance of an optical device such as a camera or video equipped with the diffractive optical element is provided. Can be improved.

It is sectional drawing at the time of shaping | molding of the diffractive optical element concerning embodiment of this invention. It is explanatory drawing of the shaping | molding method of the diffractive optical element concerning embodiment of this invention. It is sectional drawing of the edge part of the metal mold | die concerning embodiment of this invention. It is explanatory drawing of the manufacturing method of the diffractive optical element concerning embodiment of this invention.

  FIG. 2 shows a method for forming a diffractive optical element of the present invention. Reference numeral 1 denotes a diffraction grating molding lens substrate. 2 is a mold. Reference numeral 3 denotes an optical material for forming a diffraction grating. 4 is a bank located outside the outer periphery of the optically effective portion of the mold. 6 is an ejector.

Below, the process of manufacturing a diffractive optical element will be described with reference to FIG.
First, the diffraction grating shaping optical material 3 is dropped on the molding surface side of the diffraction grating shaping lens substrate 1, and the diffraction grating shaping lens substrate 1 is placed on the mold 2. Alternatively, the molding optical material 3 is dropped near the center of the molding surface of the molding die 2, or after being dropped onto both the diffraction grating molding lens substrate 1 and the molding die 2, a diffraction grating is formed on the molding die 2. A lens substrate 1 may be placed. (FIG. 2 (a)).

  Next, the diffraction grating molding lens substrate 1 is brought close to the mold 2, the diffraction grating molding lens substrate 1 is in contact with the bank 4 on the outer periphery of the molding mold 2, and the diffraction grating molding optical material 3 is the bank 4. It is set as the state filled to the inside (FIG.2 (b)). Here, since the diffraction grating molding material 3 is filled, a method of pressing the diffraction grating molding lens substrate 1 and contacting the bank 4 is also effective. Since the height of the molded product is fixed by the bank when the diffraction grating molding lens substrate 1 is in contact with the bank 4, the height of the molded product can be controlled by the height of the bank. Next, the diffraction grating shaping optical material 3 filled in the mold 2 is cured in a state where the diffraction grating shaping lens substrate 1 is in contact with the bank 4. The diffraction grating molding optical material 3 does not need to be completely cured as long as the reaction has progressed to a degree of cure that can be released from the mold 2. Finally, the diffraction grating molding lens substrate 1 is lifted by the ejector 6 to release the diffraction grating molding lens substrate 1 from the molding die together with the hardened diffraction grating molding optical material 3 (FIG. 2C).

  FIG. 1 is a cross-sectional view of the diffractive optical element of the present invention during molding. Reference numeral 5 denotes a groove between the bank 4 of the mold and the outermost portion of the optically effective portion. The groove 5 is deeper than the deepest portion of the optically effective portion, and all the angles formed by the cross-sectional shape are obtuse angles. A diffractive optical element is molded using a mold 2 having a bank 4 and a groove 5. The molding die 2 may be obtained by molding from a master die, or may be formed by cutting or polishing a base material or a plating layer formed on the base material.

  The bank 4 suppresses the movement and deformation of the diffraction grating molding lens substrate 1 in the direction of the mold 2, so that a transfer failure of the diffraction grating occurs at the outer peripheral portion in the optically effective portion. However, at the same time, by providing the groove 5 deeper than the diffraction grating in the effective portion between the bank 4 and the optical effective portion, transfer defects in the optical effective portion can be improved. This is because the groove 5 is deeper than the shape in the optically effective portion, so that a large stress is applied to the diffraction grating molding lens substrate 1 due to the shrinkage of the resin in the groove 5, and the diffraction grating molding lens substrate 1 above the groove 5 is molded. This is because it moves and deforms greatly in the mold 2 direction.

  Here, since the groove 5 is deeper than the inside of the optically effective portion, the molding optical material 3 filled in the groove 5 has a new shrinkage stress, which causes a new problem that it is easy to peel from the mold 2. When the molding optical material 3 filled in the groove 5 is peeled from the mold 2, the diffraction grating molding lens substrate 1 is not moved or deformed in the upper part of the groove 5. Can not. For this reason, as shown to Fig.3 (a), all the angles which the cross section of a groove | channel makes are obtuse angles, and peeling from the shaping | molding die 2 is prevented. 7 in FIG. 3A shows the outermost part of the optically effective portion. The groove 5 is disposed between the bank 4 and the outermost part 7 of the optically effective portion. If there is an acute angle portion in the cross-sectional shape of the groove 5, stress due to curing shrinkage of the molding optical material 3 is concentrated at the sharp tip portion, and the molding optical material 3 at the acute angle portion is peeled off from the mold 2. To do. If the cross-sectional shape is a groove having an obtuse angle, peeling of the molding optical material 3 from the molding die 2 can be prevented without causing local stress concentration. Even if the cross-sectional shape is a smooth curve, local stress concentration does not occur, and the same effect can be obtained. Here, the smooth cross-sectional shape means that in the coordinate system in which the y-axis is parallel to the optical axis, the x-axis is perpendicular to the y-axis and the x-axis is in the cross-sectional direction, the groove 5 is y = f (x) Dy / dx = df / dx means continuous.

  In this way, the groove 5 having an obtuse angle or a smooth curve is provided on the side of the outermost portion 7 and the bank 4 of the optically effective portion. As a result, the deformation of the diffraction grating molding lens substrate 1 by the bank 4 can be suppressed, and at the same time, the diffraction grating molding lens substrate 1 can be greatly deformed and moved by the grooves 5, thereby improving the transfer failure of the optically effective portion. The

[Example 1]
The diffractive optical element manufactured in this example will be described with reference to FIG.

  The diffractive optical element of this embodiment includes a diffraction grating molding lens substrate 1 and a molding optical material 3 composed of a fluororesin and an acrylic resin in which ITO (indium oxide) fine particles are dispersed. The lens substrate 1 for forming a diffraction grating has a flat plate shape with a diameter of 50 mm and a thickness of 5 mm. The fluororesin 3 in which the ITO fine particles are dispersed has photocurability, and the nano-sized ITO fine particles are uniformly dispersed at 20 vol% in the fluororesin, so that it has a dark blue appearance. The diffraction grating of the diffractive optical element to be molded is a blazed diffraction grating having a diffraction grating height of 9 to 11 μm and a diffraction grating width of 0.1 to 10 mm, and is formed concentrically.

  A molding die 2 used for molding the diffractive optical element of this embodiment will be described with reference to FIG.

  The molding die 2 has a reverse shape of a desired diffraction grating on its molding surface, and a bank 4 and a groove 5 on the outer periphery of the optically effective portion. The molding surface of the mold 2 is formed by cutting onto NiP formed as a plating layer on a metal base material. The diffraction grating on the molding surface of the mold 2 is a blazed diffraction grating having a diffraction grating height of 9 to 11 μm and a diffraction grating width of 0.1 to 10 mm, and is formed concentrically with a concave portion at the center.

  The height of the bank 4 positioned outside the effective diameter of the molding die 2 is the diffraction grating height + 2 μm (11 to 13 μm), and is molded while being pressed so that the diffraction grating molding lens substrate 1 is in contact with the bank 4. Thus, the overall height of the molded product can be controlled at ± 0.5 μm. The resin in which the ITO fine particles used in this example are dispersed is dark blue and has low light transmittance at a low wavelength. Therefore, it is necessary to control the height of the molded product excluding the diffraction grating at 2 ± 0.5 μm, and it is necessary to mold with the molding die 2 having the bank 4 on the outer periphery of the optically effective portion. Further, the groove 5 is located between the optically effective outermost part and the bank, the maximum depth is 30 μm, the lateral width is 0.8 mm, and the cross-sectional shape of the mold has three angles, and the angle formed is 100˜ All of them have an obtuse angle of 120 °. The fluororesin 3 in which the ITO fine particles are dispersed fills the diffraction grating and the groove 5 of the mold 2 without excess or deficiency.

  A method of molding the diffractive optical element of this example will be described in order with reference to FIG.

  First, the molding surface of the diffraction grating molding lens substrate 1 is subjected to a silane coupling treatment for strengthening the close contact with the fluororesin in which ITO fine particles as the molding optical material 3 are dispersed.

  Next, an appropriate amount of the molding optical material 3 is dropped near the center of the silane coupling treatment surface of the diffraction grating molding lens substrate 1 (FIG. 2A). Next, the diffraction grating molding lens substrate 1 placed on the molding die 2 is pressed with 300 kgf to bring the diffraction grating molding lens substrate 1 into contact with the bank 4 on the molding die 2 (FIG. 2B). By pressing the diffraction grating molding lens substrate 1, the molding optical material 3 is uniformly extended to the height of the bank 4. Since the fluororesin in which ITO fine particles dispersed as the molding optical material 3 have a dark blue appearance, it is necessary to extend the thickness to 2 μm to increase transparency, and the diffraction grating molding lens substrate 1 is provided on the bank 4. By pressing, the thickness excluding the diffraction grating portion of the molded product is controlled to 2 ± 0.5 μm.

Next, the filled optical molding material 3 is irradiated with ultraviolet light from an unillustrated ultraviolet irradiation lamp to cure the molding optical material 3. At this time, in order to relieve stress concentration due to curing shrinkage by slowly advancing the reaction of the molding optical material 3, first, 15J (15 mW / cm ²⁾ is used in a state where low-wavelength light is blocked using a 400 nm low-pass filter. X 1000 seconds). Then, in order to advance reaction until it can mold-release, the ultraviolet light which removed the low-pass filter is irradiated for 0.3J (3mW / cm < ² > * 100 second).

  The fluororesin in which ITO fine particles, which are the molding optical material 3, are dispersed, shrinks by about 10% when cured. Due to the shrinkage of the molding optical material 3, the diffraction grating molding lens substrate 1 is pulled in the direction of the molding die 2 to move and deform. In the portion of the diffraction grating molding lens substrate 1 that is in contact with the bank 4, the movement in the direction of the molding die 2 is restricted, and movement / deformation corresponding to the shrinkage of the molding optical material 3 does not occur. Further, since the groove 5 is deeper than the optically effective portion, the diffraction grating molding lens substrate 1 above the groove 5 is larger in the direction of the mold 2 due to curing shrinkage of the molding optical material 3 in the groove 5. Causes movement and deformation. The grooves 5 can alleviate the influence of deformation suppression of the bank 4 and can suppress the occurrence of transfer failure.

  The groove | channel of the shaping | molding die used for a present Example is demonstrated with reference to FIG.

  Since the groove 5 is 30 μm deeper than the diffraction grating of the diffractive optical element, the molding optical material 3 in the groove 5 has a large concentration of stress due to curing shrinkage. In particular, when the groove has a portion with a sharp cross-sectional shape, a large stress concentration is locally generated at the portion, and the molding optical material 3 is peeled off from the molding die 2. Therefore, the groove 5 needs to have a shape in which the cross-sectional shape forms an obtuse angle as shown in FIG. 3A, or a shape formed of a smooth curve as shown in FIG.

  Finally, the ejector 6 is raised relative to the mold 2 to release the cured molding optical material 3 together with the diffraction grating molding lens substrate 1 (FIG. 2C).

  Thus, according to this example, a diffractive optical element with excellent optical performance can be manufactured in a state in which the height of the molded product is controlled and the shape of the tip of the diffraction grating is stable. Can be manufactured. Furthermore, since the production yield is improved by suppressing the occurrence of transfer defects, the manufacturing cost of the diffractive optical element can be reduced. In addition, since the shape stability of the diffraction grating tip of the diffractive optical element is good, the optical performance of an optical device such as a camera or video equipped with the diffractive optical element can be improved.

[Comparative Example 1]
In the manufacturing method of the diffractive optical element of Example 1, when the maximum depth of the groove 5 was 10 μm and the angles formed by the cross-sectional shapes were all obtuse, the same molding was performed.
In the portion of the diffraction grating molding lens substrate 1 that is in contact with the bank 4, the movement in the direction of the molding die 2 is restricted, and movement / deformation corresponding to the shrinkage of the molding optical material 3 does not occur. Further, when the maximum depth of the groove 5 is 10 μm, since the depth is shallower than the diffraction grating of the diffractive optical element, the lens substrate 1 for forming a diffraction grating at the upper part of the groove 5 is formed in the groove 5. There is little movement or deformation in the direction of the mold 2 due to curing shrinkage of the optical material 3 for use. Therefore, the effect of alleviating the influence of the deformation suppression of the bank 4 by the grooves 5 is not sufficient, and a transfer failure occurs.
When the maximum depth of the groove 5 was 10 μm, transfer failure occurred in the diffraction grating existing from the outer periphery of the optically effective portion to 0.3 mm, resulting in a shape different from the desired shape by 100 to 300 nm. Due to this transfer failure, a decrease in diffraction efficiency was observed on the outer periphery of the optically effective portion, resulting in a problem in optical performance. From this result, it can be said that the maximum depth of the groove 5 needs to be deeper than the shape of the diffraction grating.

[Example 2]
In the manufacturing method of the diffractive optical element of Example 1, when the maximum depth of the shape of the groove 5 was 30 μm, the lateral width was 0.5 mm, and the angles formed by the cross-sectional shapes were all obtuse, the same molding was performed. .
Since the maximum depth of the groove 5 is 30 μm and is deeper than the diffraction grating of the diffractive optical element, the lens substrate 1 for forming the diffraction grating at the upper part of the groove 5 is formed by the molding optical material in the groove 5. 3 greatly moves and deforms in the direction of the mold 2 due to curing shrinkage. By this movement / deformation, the transfer defect on the outer periphery of the optically effective portion can be suppressed due to the effect of alleviating the influence of the deformation suppression of the bank 4 by the groove 5.
Even when the lateral width of the groove 5 was 0.5 mm, no transfer failure occurred at all in the diffraction grating present on the outer periphery of the optically effective portion. From this result, it can be said that if the groove 5 has a maximum depth deeper than the shape of the diffraction grating and the cross section has an obtuse angle, the groove 5 can exhibit the effect of suppressing the transfer failure without depending on the lateral width. .

[Example 3]
The diffractive optical element manufactured in this example will be described with reference to FIG.

The diffractive optical element of the present embodiment includes a diffraction grating molding lens substrate 1, an epoxy resin 3 in which ZrO ₂ (zirconia oxide) fine particles are dispersed, an acrylic resin 3 in which TiO ₂ (titanium oxide) fine particles are dispersed, and a bonding lens substrate. It is composed of nine. The diffraction grating molding lens substrate 1 has a concave lens shape with a diameter of 60 mm and a maximum thickness of 3 mm. The epoxy resin 3 in which the ZrO ₂ fine particles are dispersed has photocurability, and nano-sized ZrO ₂ fine particles are uniformly dispersed in the epoxy resin at 5 vol%, and has a colorless and transparent appearance. The acrylic resin 8 in which the TiO ₂ fine particles are dispersed similarly has photocurability and has a white appearance because the nano-sized TiO ₂ fine particles are uniformly dispersed at 10 vol% in the acrylic resin. The bonding lens substrate 9 has a convex lens shape with a diameter of 58 mm and a maximum thickness of 10 mm. The diffraction grating between the epoxy resin 3 in which the ZrO ₂ fine particles are dispersed and the acrylic resin 8 in which the TiO ₂ fine particles are dispersed is a blazed diffraction grating having a diffraction grating height of 15 μm and a diffraction grating width of 0.5 to 3 mm. Is formed.

  A molding die used for molding the diffractive optical element of this example will be described with reference to FIG. The molding die 2 has, on its molding surface, a reversal shape of a desired diffraction grating and a convex portion 10 for forming a groove 5 and a concave portion 11 for forming a bank 4. The diffraction grating on the molding surface of the mold 2 is a blazed diffraction grating having a diffraction grating height of 15 μm and a diffraction grating width of 0.5 to 3 mm, and is formed concentrically with a convex portion toward the center. The convex portions 10 for forming the grooves 5 are concentrically formed on the outer peripheral portion outside the optical effective diameter with a height of 30 μm and an obtuse cross section. Further, the recess 11 for forming the bank 4 has a depth of 20 μm. The molding surface of the mold 2 is formed by cutting onto Opt-Cu formed as a plating layer on a metal base material.

  A method of manufacturing the diffractive optical element of this example will be described in order with reference to FIG.

First, a silane coupling process is performed on one surface of the diffraction grating molding lens substrate 1 in order to strengthen the adhesion with the epoxy resin 3 in which ZrO ₂ fine particles are dispersed.

An appropriate amount of epoxy resin 3 in which ZrO ₂ fine particles are dispersed is dropped in the vicinity of the center of the silane coupling surface of the diffraction grating molding lens substrate 1 with a dispenser. Alternatively, the epoxy resin 3 in which ZrO ₂ fine particles are dispersed may be dropped near the center of the molding surface of the mold 2.

Next, the diffraction grating molding lens substrate 1 placed on the mold 2 is filled with an epoxy resin 3 in which ZrO ₂ fine particles are dispersed (FIG. 4A). The epoxy resin 3 in which the filled ZrO ₂ fine particles are dispersed is irradiated with 30 J (100 [mW / cm ² ] × 300 seconds) of ultraviolet light from an ultraviolet irradiation lamp to cure the epoxy resin 3 in which the ZrO ₂ fine particles are dispersed. Let

  Next, in order to release the cured epoxy resin 3 and the diffraction grating molding lens substrate 1, the diffraction grating molding lens substrate 1 is cooled with liquid nitrogen. By cooling, the epoxy resin 3 molded on the diffraction grating molding lens substrate 1 begins to peel from the molding die 2 from the outer periphery. When the peeling is started, the ejector 6 is raised relative to the mold 2 and the diffraction grating molding lens substrate 1 is lifted to release the entire surface, and a molded product is obtained (FIG. 4B).

Subsequently, a silane coupling process is performed on one surface of the bonding lens substrate 9 in order to strengthen the adhesion with the acrylic resin 8 in which TiO ₂ fine particles are dispersed.

An appropriate amount of acrylic resin 8 in which TiO ₂ fine particles are dispersed is dropped in the vicinity of the center of the silane coupling treatment surface of the bonding lens substrate 9 with a dispenser. Alternatively, the acrylic resin 8 in which TiO ₂ fine particles are dispersed may be dropped near the center of the diffraction grating surface made of the epoxy resin 3 in which ZrO ₂ fine particles formed on the diffraction grating molding lens substrate 1 are dispersed (FIG. 4). (C)).

Next, the bonding lens substrate 9 placed on the epoxy resin 3 in which the ZrO ₂ fine particles are dispersed is pressed with 300 kgf, and the acrylic resin 8 in which the TiO ₂ fine particles are dispersed is filled on the bonding lens substrate 9. By pressing the bonding lens substrate 9 with 300 kgf, the bank 4 formed of the epoxy resin 3 in which ZrO ₂ fine particles are dispersed is brought into contact with the bonding lens substrate 9 (FIG. 4D). By bringing the bank 4 and the bonding lens substrate 9 into contact, the acrylic resin 8 in which the TiO ₂ fine particles are dispersed is uniformly stretched to the height of the bank 4. Since the acrylic resin 8 in which the TiO ₂ fine particles are dispersed has a white appearance, it is necessary to increase the transparency by increasing the thickness to 5 μm. By pressing the bonding lens substrate 9 against the bank 4, the TiO ₂ fine particles are The thickness of the dispersed acrylic resin 8 excluding the diffraction grating portion is controlled.

Next, the acrylic resin 8 in which the filled TiO ₂ fine particles are dispersed is cured by irradiating with ultraviolet light of 15 J (50 [mW / cm ² ] × 300 seconds) by an ultraviolet irradiation lamp (not shown).

Since the acrylic resin 8 in which the TiO ₂ fine particles are dispersed shrinks when cured, the bonding lens substrate 9 is pulled in the direction of the mold 2 and is moved and deformed. The portion of the bonding lens substrate 9 that is in contact with the bank 4 is restrained from moving in the direction of the mold 2 and does not move or deform according to the contraction of the acrylic resin 8 in which the TiO ₂ fine particles are dispersed. Since the groove 5 is deeper than the optically effective portion, the bonding lens substrate 9 at the upper part of the groove 5 is formed in the two directions of the mold by curing shrinkage of the acrylic resin 8 in which the TiO ₂ fine particles in the groove 5 are dispersed. Cause significant movement and deformation. The groove 5 can alleviate the influence of deformation suppression of the bank 4 and can improve the occurrence of transfer failure.

  Thus, according to the present embodiment, a diffractive optical element with excellent optical performance can be manufactured in a state in which the height of the diffractive optical element is controlled and the shape of the tip of the diffraction grating is stable. Can be manufactured. Furthermore, since the production yield is improved by suppressing the occurrence of transfer defects, the manufacturing cost of the diffractive optical element can be reduced. In addition, since the shape stability of the diffraction grating tip of the diffractive optical element is good, the optical performance of an optical device such as a camera or video equipped with the diffractive optical element can be improved.

DESCRIPTION OF SYMBOLS 1 Diffraction-grating lens substrate 2 Mold 3 Diffraction-grating optical material 4 Bank 5 Groove 6 Ejector 7 Optical outermost part 8 Bonding optical material 9 Bonding lens substrate 10 Convex part 11 for groove formation Recess for forming

Claims (3)

  In a method for manufacturing a diffractive optical element, which includes a step of transferring a shape of a molding die using a molding optical material, using a molding die having a bank outside the outer periphery of the optically effective portion, the outermost of the molding die and the optically effective portion. A method for manufacturing a diffractive optical element, comprising using a molding die having a groove deeper than a deepest portion of an optically effective portion and having an obtuse angle with a cross-sectional shape between the outside and the outside.   In a method for manufacturing a diffractive optical element, which includes a step of transferring a shape of a molding die using a molding optical material, using a molding die having a bank outside the outer periphery of the optically effective portion, the outermost of the molding die and the optically effective portion. A method for producing a diffractive optical element, comprising using a molding die having a groove that is deeper than the deepest portion of the optically effective portion and has a smooth cross-sectional shape between the outside and the outside.   A diffractive optical element manufactured using the manufacturing method according to claim 1.

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