JP2021009199A - Diffraction optical element, method for manufacturing diffraction optical element, and imaging apparatus - Google Patents

Abstract

To provide a diffraction optical element in which chipping hardly occurs in a diffraction grating of a resin layer.SOLUTION: A diffraction optical element 20 has a base material 1, a first resin layer 3 having a diffraction grating composed of a plurality of inclined surfaces 51 and a plurality of wall surfaces 52, and a second resin layer 4, which are laminated in order, and in plan view from the lamination direction, the diffraction grating forms ring zones composed of a plurality of concentric circles. In the diffraction optical element 20, the average surface roughness at a reference length 50 μm of the inclined surface is the maximum value Rmax on the inclined surface of a final ring zone 513 that is farthest from the center of the concentric circles. The average surface roughness is the minimum value Rmin on the inclined surface of a minimum ring zone 512 between a first ring zone 511 and the final ring zone 513 surrounding the center of the concentric circles. The average surface roughness of the inclined surface of the first ring zone 511 is larger than Rmin and smaller than Rmax.SELECTED DRAWING: Figure 1

Description

本発明はカメラやビデオ等の撮像装置に使用される回折光学素子およびその製造方法に関する。 The present invention relates to a diffractive optical element used in an imaging device such as a camera or a video, and a method for manufacturing the same.

レンズなどに用いられる光学素子として、光学特性が異なる２種類の樹脂の境界面にレリーフパターンを有する密着２層型の回折光学素子が知られている。この回折光学素子を得るために、特許文献１のように、レプリカ成形法を用いてレンズ基板上に所望のレリーフパターンを有する樹脂層を形成することが知られている。しかし、この回折光学素子を光学系に用いると、色収差の低減が期待される一方で、フレアと呼ばれる不要光が発生することがある。近年、カメラやビデオ等の撮像装置の高画質化に伴い、レンズにはより高い光学性能が要求されており、ユーザーのフレアの低減に対するニーズが高まっている。 As an optical element used for a lens or the like, a close-contact two-layer diffractive optical element having a relief pattern on a boundary surface between two types of resins having different optical characteristics is known. In order to obtain this diffractive optical element, it is known that a resin layer having a desired relief pattern is formed on a lens substrate by using a replica molding method as in Patent Document 1. However, when this diffractive optical element is used in an optical system, it is expected that chromatic aberration will be reduced, but unnecessary light called flare may be generated. In recent years, with the improvement of image quality of image pickup devices such as cameras and videos, higher optical performance is required for lenses, and there is an increasing need for users to reduce flare.

フレアを抑制させる手段としては、回折格子の斜面に対する壁面の角度を、光線の入射方向と平行に近づけることが知られている。 As a means for suppressing flare, it is known that the angle of the wall surface with respect to the slope of the diffraction grating is brought close to parallel to the incident direction of the light beam.

特開２００７−２１２５４７号公報JP-A-2007-212547

しかしながら、樹脂層の回折格子の斜面に対する壁面の角度を光線の入射方向と平行に近づけたり、樹脂の材料種によっては、樹脂層を形成するために離型する際に回折格子に欠けが生じてしまうことがあった。 However, the angle of the wall surface of the resin layer with respect to the slope of the diffraction grating is made parallel to the incident direction of the light beam, and depending on the resin material type, the diffraction grating is chipped when the mold is released to form the resin layer. There was a case that it ended up.

上記課題を解決するための回折光学素子は、基材と、複数の斜面と複数の壁面とからなる回折格子を有する第１樹脂層と、第２樹脂層と、が順に積層され、積層方向から平面視した際に、前記回折格子が複数の同心円からなる輪帯を形成する回折光学素子において、前記斜面の基準長さ５０μｍにおける平均表面粗さが、前記同心円の中心から最も遠い最終輪帯の斜面で最大値Ｒｍａｘであり、前記同心円の中心を囲む第１輪帯と前記最終輪帯との間の最小輪帯の斜面で最小値Ｒｍｉｎであり、前記第１輪帯の斜面の平均表面粗さが前記Ｒｍｉｎより大きく、かつ、前記Ｒｍａｘより小さいことを特徴とする。 In the diffractive optical element for solving the above problems, a base material, a first resin layer having a diffraction grating composed of a plurality of slopes and a plurality of wall surfaces, and a second resin layer are laminated in order, and from the stacking direction. In a diffractive optical element in which the diffraction grating forms an annular zone composed of a plurality of concentric circles when viewed in a plan view, the average surface roughness of the slope at a reference length of 50 μm is the final annular zone farthest from the center of the concentric circles. The maximum value Rmax on the slope, the minimum value Rmin on the slope of the minimum grating between the first and final gratings surrounding the center of the concentric circle, and the average surface roughness of the slope of the first grating. Is larger than the Rmin and smaller than the Rmax.

また、上記課題を解決するための回折光学素子の製造方法は、複数の斜面と複数の壁面から複数の同心円からなる輪帯を形成する回折格子を反転した形状を有する型と、基材との間に第１樹脂を設ける工程と、前記第１樹脂に熱または光エネルギーを与えて前記第１樹脂を硬化させ、前記型を周縁から中心に向かって離型して第１樹脂層を得る工程と、前記第１樹脂層上に第２樹脂を設ける工程と、前記第２樹脂に熱または光エネルギーを与えて前記第２樹脂を硬化させる工程と、を備える回折光学素子の製造方法であって、前記型の斜面の基準長さ５０μｍにおける平均表面粗さが、前記同心円の中心から最も遠い最終輪帯の斜面で最大値Ｒｍａｘであり、前記同心円の中心を囲む第１輪帯と前記最終輪帯との間の最小輪帯の斜面で最小値Ｒｍｉｎであり、前記第１輪帯の斜面の平均表面粗さが前記Ｒｍｉｎより大きく、かつ、前記Ｒｍａｘより小さいことを特徴とする。 Further, a method for manufacturing a diffractive optical element for solving the above problems is to use a mold having an inverted shape of a diffraction grating forming an annular zone composed of a plurality of concentric circles from a plurality of slopes and a plurality of wall surfaces, and a base material. A step of providing a first resin between them, and a step of applying heat or light energy to the first resin to cure the first resin and releasing the mold from the peripheral edge toward the center to obtain a first resin layer. A method for manufacturing a diffraction optical element, comprising a step of providing a second resin on the first resin layer and a step of applying heat or light energy to the second resin to cure the second resin. The average surface roughness of the slope of the mold at a reference length of 50 μm is the maximum value Rmax on the slope of the final grating farthest from the center of the concentric circles, and the first and final wheels surrounding the center of the concentric circles. It is a minimum value Rmin on the slope of the minimum ring zone between the bands, and the average surface roughness of the slope of the first ring zone is larger than the Rmin and smaller than the Rmax.

本発明によれば、格子斜面に対する格子壁面の角度が大きくても、離型の際に欠けが生じにくい回折光学素子を提供することができる。 According to the present invention, it is possible to provide a diffractive optical element in which chipping is unlikely to occur at the time of mold release even if the angle of the lattice wall surface with respect to the lattice slope is large.

本発明の回折光学素子の一実施態様を示す概略図である。It is the schematic which shows one Embodiment of the diffraction optical element of this invention. 本発明の回折光学素子における、回折格子の第１輪帯から最終輪帯までの斜面の平均表面粗さの一実施態様を示した概略図である。It is a schematic diagram which showed one Embodiment of the average surface roughness of the slope from the 1st ring zone to the last ring zone of the diffraction grating in the diffraction optical element of this invention. 本発明の回折光学素子の製造方法に用いる型の概略図である。It is the schematic of the mold used in the manufacturing method of the diffractive optical element of this invention. 本発明の回折光学素子の製造方法における第１樹脂層の形成工程を示した概略図である。It is the schematic which showed the formation process of the 1st resin layer in the manufacturing method of the diffractive optical element of this invention. 第１樹脂層の形成構成における離型工程を示した概略図である。It is the schematic which showed the mold release process in the formation structure of the 1st resin layer. 本発明の回折光学素子の製造方法における第２樹脂層の形成工程を示した概略図である。It is the schematic which showed the formation process of the 2nd resin layer in the manufacturing method of the diffractive optical element of this invention. 本発明の撮像装置の一実施態様を示す概略図である。It is the schematic which shows one Embodiment of the image pickup apparatus of this invention.

［回折光学素子］
図１は本発明の回折光学素子の一実施態様を示すものであり、図１（ａ）は側面図、図１（ｂ）は上面図である。 [Diffractive optical element]
1A and 1B show one embodiment of the diffractive optical element of the present invention, FIG. 1A is a side view and FIG. 1B is a top view.

回折光学素子２０は、第１基材１と、第１基材上に複数の斜面５１と複数の壁面５２よりなる回折格子を有する第１樹脂層３と、第２樹脂層４とが順に密着して積層されている。また、回折光学素子２０を積層方向から平面視した際に、回折格子は同心円状に形成されている。 In the diffraction optical element 20, the first base material 1, the first resin layer 3 having a diffraction grating composed of a plurality of slopes 51 and a plurality of wall surfaces 52 on the first base material, and the second resin layer 4 are in close contact with each other in order. And are laminated. Further, when the diffraction optical element 20 is viewed in a plan view from the stacking direction, the diffraction grating is formed concentrically.

（基材）
第１基材１は透明基材であり、例えば、ランタン系の高屈折率低分散ガラスであるＳ−ＬＡＨ５５（株式会社オハラ製）や超低分散ガラスであるＳ−ＦＰＬ５１（株式会社オハラ製）などを用いることができる。図１において、第１基材５はメニスレンズであるが、平板レンズであっても構わない。また、第２樹脂層４の上に第２基材２を設けても構わない。第２基材２は、例えば、第１基材１と同様に透明基材を用いることができる。 (Base material)
The first base material 1 is a transparent base material, for example, S-LAH55 (manufactured by OHARA Corporation) which is a lantern-based high refractive index low dispersion glass and S-FPL51 (manufactured by OHARA Corporation) which is an ultra-low dispersion glass. Etc. can be used. In FIG. 1, the first base material 5 is a menis lens, but it may be a flat lens. Further, the second base material 2 may be provided on the second resin layer 4. As the second base material 2, for example, a transparent base material can be used in the same manner as the first base material 1.

（樹脂層）
第１樹脂層３および第２樹脂層４は、例えば、無色透明な樹脂から構成され、回折光学素子が所望の光学特性となるように屈折率やアッベ数が設計されている。広い波長帯域で高い回折効率を得るために、第１樹脂層３と第２樹脂層４は低屈折率高分散樹脂と高屈折率低分散樹脂とすることが好ましい。ここで、低屈折率および高屈折率とは第１樹脂層３および第２樹脂層４の屈折率（ｄ線の屈折率ｎｄ）の相対的な関係を意味する。同様に、高分散および低分散とは第１樹脂層３および第２樹脂層４の分散特性（アッベ数νｄ）の相対的な関係を意味する。つまり、第１樹脂層３が低屈折率高分散、第２樹脂層４が高屈折率低分散であるとは、第１樹脂層３の屈折率をｎｄ１、アッベ数をν１、第２樹脂層４の屈折率をｎｄ２、アッベ数をν２としたときに、ｎｄ１＜ｎｄ２及びν１＜ν２を満たすことを意味する。なお、所望の光学特性によっては、第１樹脂層３を高屈折率低分散に、第２樹脂層４は低屈折率高分散としても構わない。 (Resin layer)
The first resin layer 3 and the second resin layer 4 are made of, for example, a colorless and transparent resin, and the refractive index and the Abbe number are designed so that the diffractive optical element has desired optical characteristics. In order to obtain high diffraction efficiency in a wide wavelength band, it is preferable that the first resin layer 3 and the second resin layer 4 are a low refractive index high dispersion resin and a high refractive index low dispersion resin. Here, the low refractive index and the high refractive index mean the relative relationship between the refractive indexes of the first resin layer 3 and the second resin layer 4 (the refractive index nd of the d-line). Similarly, high dispersion and low dispersion mean the relative relationship between the dispersion characteristics (Abbe number νd) of the first resin layer 3 and the second resin layer 4. That is, the fact that the first resin layer 3 has a low refractive index and high dispersion and the second resin layer 4 has a high refractive index and low dispersion means that the refractive index of the first resin layer 3 is nd1, the Abbe number is ν1, and the second resin layer. When the refractive index of 4 is nd2 and the Abbe number is ν2, it means that nd1 <nd2 and ν1 <ν2 are satisfied. Depending on the desired optical characteristics, the first resin layer 3 may have a high refractive index and low dispersion, and the second resin layer 4 may have a low refractive index and high dispersion.

第１樹脂層３は、可視域全域で９９％以上という高い回折効率を得るために、部分分散比θｇＦが小さいリニア分散特性を有する樹脂にすることが好ましい。このリニア分散特性を得るためには、樹脂に無機酸化物の微粒子（平均粒子径が５〜２０ｎｍ程度）を含有させることができる。樹脂としては、熱硬化性樹脂および紫外線硬化樹脂等の硬化性樹脂を用いることができ、エポキシ樹脂やアクリル樹脂が好ましい。また、無機酸化物の微粒子としては、例えば、Ｓｎがドープされた酸化インジウム（ＩＴＯ）やＳｂがドープされた酸化インジウム（ＡＴＯ）を用いることができる。 The first resin layer 3 is preferably made of a resin having a linear dispersion characteristic with a small partial dispersion ratio θgF in order to obtain a high diffraction efficiency of 99% or more in the entire visible region. In order to obtain this linear dispersion characteristic, the resin can contain fine particles of inorganic oxide (average particle size of about 5 to 20 nm). As the resin, a curable resin such as a thermosetting resin and an ultraviolet curable resin can be used, and an epoxy resin or an acrylic resin is preferable. Further, as the fine particles of the inorganic oxide, for example, Sn-doped indium oxide (ITO) or Sb-doped indium oxide (ATO) can be used.

第１樹脂層３は複数の斜面５１と複数の壁面５２よりなる回折格子を有する。この回折格子は、積層方向から平面視した際に、回折光学素子の中心（光軸Ｏと一致する）としたＮ個（Ｎは２以上の整数）の円からなる同心円状のレリーフパターンからなる。レリーフパターンにおける格子ピッチは、回折光学素子の中心近傍では大きく、周縁に向かうほどが小さい。光の収斂作用や発散作用を発現させるためである。本明細書においては、同心円の中心を囲む円の領域を第１輪帯１４と呼ぶ。また、中心から数えて２番目の円と中心を囲むと円とで囲まれた領域を第２輪帯１５、中心から数えて３番目の円と２番目の円とで囲まれた領域を第３輪帯１６と呼ぶ。すなわち、中心から数えてＮ番目の円と（Ｎ−１）番目の円とで囲まれた領域を第Ｎ輪帯と呼ぶ。図１の回折光学素子の輪帯の数は５つである。 The first resin layer 3 has a diffraction grating composed of a plurality of slopes 51 and a plurality of wall surfaces 52. This diffraction grating consists of a concentric relief pattern consisting of N circles (N is an integer of 2 or more) as the center of the diffraction optical element (corresponding to the optical axis O) when viewed in a plan view from the stacking direction. .. The lattice pitch in the relief pattern is large near the center of the diffractive optical element and small toward the periphery. This is to exhibit the astringent and divergent effects of light. In the present specification, the region of the circle surrounding the center of the concentric circle is referred to as the first wheel band 14. In addition, the area surrounded by the second circle counting from the center and the circle surrounding the center is the second wheel zone 15, and the area surrounded by the third circle and the second circle counting from the center is the second ring zone 15. It is called a three-wheel band 16. That is, the region surrounded by the Nth circle and the (N-1) th circle counting from the center is called the Nth ring zone. The number of ring bands of the diffractive optical element in FIG. 1 is five.

第１樹脂層の斜面５１は、粗面であり、その平均表面粗さは場所によって異なる。具体的には、回折光学素子の中心から最も遠い位置にある最終輪帯（図１においては第５輪帯）の斜面５１３の平均表面粗さが最大値Ｒｍａｘとなる。なお、Ｒｍａｘは１０ｎｍ以上であることが好ましい。また、第１輪帯と最終輪帯との間の輪帯（最小輪帯）の斜面５１２の平均表面粗さが最小値Ｒｍｉｎとなる。なお、Ｒｍｉｎは５ｎｍ以下であることが好ましい。図１において、最小斜面は第２輪帯の斜面５１２であるが、第３輪帯の斜面であってもよい。また、第１輪帯の斜面の平均表面粗さＲ０はＲｍｉｎより大きく、かつＲｍａｘより小さい。なお、Ｒ０はＲｍｉｎの２倍以上であることが好ましい。そして、最小輪帯と最終輪帯との間に位置する中間輪帯の斜面の平均表面粗さは、前記最小値から前記最大値まで連続的もしくは断続的に大きくなっている。図１において、最小輪帯が第２輪帯のとき中間輪帯は第３輪帯および第４輪帯であり、最小輪帯が第３輪帯のとき中間輪帯は第４輪帯である。 The slope 51 of the first resin layer is a rough surface, and the average surface roughness thereof varies depending on the location. Specifically, the average surface roughness of the slope 513 of the final ring zone (fifth wheel zone in FIG. 1) located farthest from the center of the diffractive optical element is the maximum value Rmax. The Rmax is preferably 10 nm or more. Further, the average surface roughness of the slope 512 of the ring zone (minimum ring zone) between the first ring zone and the final ring zone is the minimum value Rmin. The Rmin is preferably 5 nm or less. In FIG. 1, the minimum slope is the slope 512 of the second wheel zone, but it may be the slope of the third wheel band. Further, the average surface roughness R0 of the slope of the first wheel zone is larger than Rmin and smaller than Rmax. It is preferable that R0 is twice or more of Rmin. The average surface roughness of the slope of the intermediate ring zone located between the minimum ring zone and the final ring zone is continuously or intermittently increased from the minimum value to the maximum value. In FIG. 1, when the minimum ring zone is the second ring zone, the intermediate ring zone is the third ring zone and the fourth ring zone, and when the minimum ring zone is the third ring zone, the intermediate ring zone is the fourth ring zone. ..

なお、本明細書における平均表面粗さとは、基準長さ５０μｍにおける粗さ曲線の算術平均高さ（Ｒａ）を意味している。 The average surface roughness in the present specification means the arithmetic mean height (Ra) of the roughness curve at a reference length of 50 μm.

図２は本発明の回折光学素子における、回折格子の第１輪帯から最終輪帯までの斜面の平均表面粗さの一実施態様を示した概略図である。図２（ａ），（ｂ）の回折光学素子の輪帯の数は１１である。 FIG. 2 is a schematic view showing an embodiment of the average surface roughness of the slope from the first ring zone to the last ring zone of the diffraction grating in the diffractive optical element of the present invention. The number of ring bands of the diffractive optical element of FIGS. 2A and 2B is 11.

図２（ａ）では、第１輪帯の平均表面粗さＲ０から連続的に平均表面粗さが小さくなり、第３輪帯で最小の平均表面粗さＲｍｉｎとなっている。第４輪帯から第１０輪帯までは、周縁に向かって平均表面粗さが連続的に大きくなっている。そして、最終輪帯において最大の平均表面粗さＲｍａｘとなっている。 In FIG. 2A, the average surface roughness is continuously reduced from the average surface roughness R0 of the first wheel zone, and is the minimum average surface roughness Rmin of the third wheel zone. From the 4th wheel zone to the 10th wheel zone, the average surface roughness increases continuously toward the peripheral edge. And it is the maximum average surface roughness Rmax in the final ring zone.

図２（ｂ）では、第１輪帯および第２輪帯の平均表面粗さＲ０から断続的に平均表面粗さが小さくなり、第３輪帯および第４輪帯で最小の平均表面粗さＲｍｉｎとなっている。第５輪帯から第１０輪帯までは、周縁に向かって平均表面粗さが断続的に大きくなっている。そして、最終輪帯において最大の平均表面粗さＲｍａｘとなっている。最小の平均表面粗さＲｍｉｎとなる最小輪帯は第１輪帯の中心から最終輪帯に向かって、１０面積パーセント以上２０面積パーセント以下の範囲に位置することが好ましい。 In FIG. 2B, the average surface roughness is intermittently reduced from the average surface roughness R0 of the first wheel band and the second wheel band, and the minimum average surface roughness in the third wheel band and the fourth wheel band. It is Rmin. From the 5th wheel zone to the 10th wheel zone, the average surface roughness increases intermittently toward the peripheral edge. And it is the maximum average surface roughness Rmax in the final ring zone. The minimum ring zone having the minimum average surface roughness Rmin is preferably located in a range of 10 area% or more and 20 area% or less from the center of the first ring zone toward the final ring zone.

後述するように、第１樹脂層３は型を用いて製造する。第１樹脂層の斜面が上述した様な平均表面粗さを有することにより、回折格子の斜面に対する壁面の角度を光線の入射方向と平行に近づけても、格子に欠損が生じにくくなる。 As will be described later, the first resin layer 3 is manufactured using a mold. Since the slope of the first resin layer has the average surface roughness as described above, even if the angle of the wall surface with respect to the slope of the diffraction grating is made close to parallel to the incident direction of the light beam, the lattice is less likely to be damaged.

また、第１樹脂層３において、最も平均表面粗さが大きい斜面が最終輪帯に存在することにより、平均表面粗さが一様な回折光学素子と比べて、第１樹脂層と第２樹脂層との外周付近における密着性が優れる。外周付近において第１樹脂層と第２樹脂層とが密着する表面積が大きいためである。そのため、外周を起点とした剥離が生じにくい。 Further, in the first resin layer 3, since the slope having the largest average surface roughness exists in the final ring zone, the first resin layer and the second resin are compared with the diffractive optical element having a uniform average surface roughness. Excellent adhesion to the outer periphery of the layer. This is because the surface area where the first resin layer and the second resin layer are in close contact with each other is large in the vicinity of the outer circumference. Therefore, peeling starting from the outer circumference is unlikely to occur.

［回折光学素子の製造方法］
（型）
まず、第１樹脂層をレプリカ成形するために用いる型について説明する。 [Manufacturing method of diffractive optical element]
(Type)
First, a mold used for replica molding the first resin layer will be described.

図３は本発明の回折光学素子の製造方法に用いる型の一実施形態を示した概略図である。型７は、回折光学素子２０の第１樹脂層３の回折格子を反転した形状を有する。すなわち、型７は第１樹脂層を形成する面に、複数の斜面７１と複数の壁面７２を有する。型の斜面７１は、粗面であり、その平均表面粗さは場所によって異なる。具体的には、型７の中心から最も遠い位置にある最終輪帯の斜面７１３の平均表面粗さが最大値Ｒｍａｘである。なお、Ｒｍａｘは１０ｎｍ以上であることが好ましい。また、第１輪帯と最終輪帯との間に位置する最小輪帯の斜面７１２の平均表面粗さが最小値Ｒｍｉｎとなる。なお、Ｒｍｉｎは５ｎｍ以下であることが好ましい。また、第１輪帯の斜面の平均表面粗さＲ０はＲｍｉｎより大きく、かつＲｍａｘより小さい。なお、Ｒ０はＲｍｉｎの２倍以上であることが好ましい。そして、最小輪帯と最終輪帯との間に位置する中間輪帯の斜面の平均表面粗さは、前記最小値から前記最大値まで連続的もしくは断続的に大きくなっている。 FIG. 3 is a schematic view showing an embodiment of a mold used in the method for manufacturing a diffractive optical element of the present invention. The mold 7 has a shape in which the diffraction grating of the first resin layer 3 of the diffraction optical element 20 is inverted. That is, the mold 7 has a plurality of slopes 71 and a plurality of wall surfaces 72 on the surface forming the first resin layer. The slope 71 of the mold is a rough surface, and the average surface roughness thereof varies from place to place. Specifically, the average surface roughness of the slope 713 of the final ring zone located farthest from the center of the mold 7 is the maximum value Rmax. The Rmax is preferably 10 nm or more. Further, the average surface roughness of the slope 712 of the minimum ring zone located between the first ring zone and the final ring zone is the minimum value Rmin. The Rmin is preferably 5 nm or less. Further, the average surface roughness R0 of the slope of the first wheel zone is larger than Rmin and smaller than Rmax. It is preferable that R0 is twice or more of Rmin. The average surface roughness of the slope of the intermediate ring zone located between the minimum ring zone and the final ring zone is continuously or intermittently increased from the minimum value to the maximum value.

型の斜面７１の平均表面粗さと、型７によって形成される第１樹脂層３の離型力（離型し難さ）の間には相関がある。具体的には型の平均表面粗さが大きくなると、離型力は小さくなる（離型し易くなる）。この理由は以下の通りである。 There is a correlation between the average surface roughness of the slope 71 of the mold and the mold release force (difficulty of mold release) of the first resin layer 3 formed by the mold 7. Specifically, the larger the average surface roughness of the mold, the smaller the mold release force (easier to release the mold). The reason for this is as follows.

一般に、樹脂に熱エネルギーまたは光エネルギーを与えて硬化させると、樹脂は収縮しようとする一方で、型は収縮せず、形状を保とうとする。そのため、樹脂は型との界面付近において収縮が規制され、樹脂の内部に圧縮応力を溜めることになる。圧縮応力が大きいと、樹脂は型から離れやすくなる。すなわち、樹脂の硬化収縮率が大きく、樹脂の内部に溜まる圧縮応力が大きい程、離型力は小さくなる。また、型の平均表面粗さが大きくなると、樹脂と型の接触する面積が大きくなる。そのため、型の平均表面粗さが大きくなると、型の単位面積当たりの樹脂の硬化収縮量が大きくなるので、離型力が小さくなるためである。 Generally, when a resin is cured by applying heat energy or light energy, the resin tends to shrink, while the mold does not shrink and tries to maintain its shape. Therefore, shrinkage of the resin is regulated near the interface with the mold, and compressive stress is accumulated inside the resin. When the compressive stress is large, the resin tends to separate from the mold. That is, the larger the curing shrinkage rate of the resin and the larger the compressive stress accumulated inside the resin, the smaller the mold release force. Further, as the average surface roughness of the mold increases, the area of contact between the resin and the mold increases. Therefore, when the average surface roughness of the mold becomes large, the amount of curing shrinkage of the resin per unit area of the mold becomes large, and the mold release force becomes small.

また、型の材質は特に限定されないが、加工性、耐久性、樹脂との密着力などの観点からステンレス鋼（ＳＵＳ材及びウッデホルム社製ＳＴＡＶＡＸなど）やＮｉＰなどの金型が好ましい。また、必要に応じてＣｒＮなどのコートを施しても良い。これらの金型を製造するために使用される切削加工機としては、ｎｍオーダーで切込みを制御出来る高精度な加工機であり、そこに使用される工具は尖鋭的な先端形状を有していて高精度な加工転写性を保証するダイヤモンドバイトが好適に使用できる。ダイヤモンドバイトを使用した場合、型の平均表面粗さは、切削速度つまり型の回転速度の調整、或いは切削時に摩擦低減の目的で噴霧される切削油の量を調整することで制御できる。 The material of the mold is not particularly limited, but a mold such as stainless steel (SUS material or STAVAX manufactured by Uddeholm) or NiP is preferable from the viewpoint of workability, durability, adhesion to resin, and the like. Further, a coat such as CrN may be applied if necessary. The cutting machine used to manufacture these dies is a high-precision machine that can control cutting in the order of nm, and the tools used there have a sharp tip shape. A diamond bite that guarantees high-precision processing transferability can be preferably used. When a diamond bite is used, the average surface roughness of the mold can be controlled by adjusting the cutting speed, that is, the rotation speed of the mold, or the amount of cutting oil sprayed for the purpose of reducing friction during cutting.

（成形工程）
本発明の製造方法は、図４，５で示す成形工程と図６に示す接合工程に大別される。 (Molding process)
The manufacturing method of the present invention is roughly classified into a molding process shown in FIGS. 4 and 5 and a joining process shown in FIG.

図４は本発明の回折光学素子の一実施態様を示す図であり、第１樹脂層を形成する成形工程を説明する図である。 FIG. 4 is a diagram showing an embodiment of the diffractive optical element of the present invention, and is a diagram for explaining a molding process for forming the first resin layer.

まず図４（ａ）のように、第１基材１上に第１樹脂層の前駆体である第１樹脂６をディスペンサーで適量滴下する。第１樹脂６は、硬化性の樹脂を含有する樹脂であり、以下は紫外線硬化型樹脂を用いた例である。 First, as shown in FIG. 4A, an appropriate amount of the first resin 6, which is a precursor of the first resin layer, is dropped onto the first base material 1 with a dispenser. The first resin 6 is a resin containing a curable resin, and the following is an example of using an ultraviolet curable resin.

次に、図４（ｂ）のように型７を用意する。型７は上述した型である。第１樹脂６を滴下した第１基材１を型７の上に配置し、第１基材１を徐々に下降させる。 Next, the mold 7 is prepared as shown in FIG. 4 (b). The mold 7 is the mold described above. The first base material 1 to which the first resin 6 is dropped is placed on the mold 7, and the first base material 1 is gradually lowered.

続いて、図４（ｃ）のように、滴下した第１樹脂６を型７に接触させる。このとき、空気（泡）を巻き込まないように第１基材１と型７との間に第１樹脂６を充填する。この際、第１基材１の第１樹脂６を設けなかった面から、加圧用ガラス８を介して第１樹脂６に圧力をかけて、回折光学素子の光学有効部外まで第１樹脂６を押し拡げる。加圧用ガラス８は、第１基材１を均一に加圧する為に使用され、第１基材１と接する側は第１基材１と同一の曲率を有する球面形状、反対側は加圧方向に対して垂直な平面である。加圧用ガラスの材質は、紫外線透過率が大きいことが好ましい。また。第１基材１と同材質であることが好ましい。 Subsequently, as shown in FIG. 4C, the dropped first resin 6 is brought into contact with the mold 7. At this time, the first resin 6 is filled between the first base material 1 and the mold 7 so as not to entrain air (foam). At this time, pressure is applied to the first resin 6 through the pressurizing glass 8 from the surface of the first base material 1 where the first resin 6 is not provided, and the first resin 6 extends to the outside of the optically effective part of the diffractive optical element. Push and spread. The pressurizing glass 8 is used to uniformly pressurize the first base material 1. The side in contact with the first base material 1 has a spherical shape having the same curvature as the first base material 1, and the opposite side has a pressing direction. It is a plane perpendicular to. The material of the pressurizing glass preferably has a high ultraviolet transmittance. Also. It is preferably made of the same material as the first base material 1.

続いて、図４（ｄ）のように、紫外線光源９から紫外線を照射して第１樹脂６を硬化させ、第１基材１上に同心円状の回折格子形状を有する第１樹脂層３を形成する。紫外線の照射量は硬化反応率が８０％以上１００％以下の範囲にするのが好ましい。８０％より小さい硬化反応率で離型を行うと、その後の形状変化量が大きいため、型の転写精度が低下するおそれがある。紫外線硬化型樹脂の反応率は、ＦＴ−ＩＲ（フーリエ変換型赤外分光計）を用いて算出することが出来る。具体的には、硬化反応に寄与するＣ＝Ｃ二重結合の振動が表す波数（８０９ｃｍ^−１）の濃度と寄与しないＣ−Ｃ単結合の振動が表す波数（７６３ｃｍ^−１）の濃度を測定し、その比率を照射量毎に算出し、初期（照射量０）との比較で反応率とする。これを事前に行って、予め照射条件を設定しておく。 Subsequently, as shown in FIG. 4D, the first resin 6 is cured by irradiating ultraviolet rays from the ultraviolet light source 9, and the first resin layer 3 having a concentric diffraction grating shape is formed on the first base material 1. Form. The irradiation amount of ultraviolet rays is preferably in the range of 80% or more and 100% or less of the curing reaction rate. If the mold is released at a curing reaction rate smaller than 80%, the amount of subsequent shape change is large, so that the transfer accuracy of the mold may decrease. The reaction rate of the ultraviolet curable resin can be calculated using FT-IR (Fourier transform infrared spectrometer). Specifically, the concentration of the wave number (809 cm ^-1 ) represented by the vibration of the C = C double bond that contributes to the curing reaction and the concentration of the wave number (763 cm ^-1 ) represented by the vibration of the CC single bond that does not contribute to the curing reaction are measured. Then, the ratio is calculated for each irradiation amount and used as the reaction rate by comparison with the initial stage (irradiation amount 0). This is done in advance and the irradiation conditions are set in advance.

硬化が終わったのち、図４（ｅ）のように、第１基材１と第１樹脂層３が一体化した成形レンズ１０を型７から離型する。この離型工程については、図５を用いて詳細に説明する。 After the curing is completed, the molded lens 10 in which the first base material 1 and the first resin layer 3 are integrated is released from the mold 7 as shown in FIG. 4 (e). This mold release step will be described in detail with reference to FIG.

図５は、レプリカ成形の離型時における基材の形状変化を模式的に表したものである。 FIG. 5 schematically shows a change in the shape of the base material at the time of mold release of replica molding.

図５（ａ）は、型７の上に第１樹脂層を介して第１基材１が配置されている状態を示す。説明の便宜上、図５では第１樹脂層を省略している。この状態では第１基材１は変形しておらず、離型も開始していないため第１基材１の全面が第１樹脂層を介して型７と接しているため密着力が強い。本発明に用いる型７は、型の中心から最も遠い位置にある最終輪帯の平均表面粗さを最大値としている。そのため、不図示の第１樹脂層は、最終輪帯で最も離型力が低く、最も離型しやすい。よって、第１樹脂層は最終輪帯が位置する周縁が離型の起点になりやすい。好ましい最終輪帯の平均表面粗さは１０ｎｍ以上である。 FIG. 5A shows a state in which the first base material 1 is arranged on the mold 7 via the first resin layer. For convenience of explanation, the first resin layer is omitted in FIG. In this state, the first base material 1 is not deformed and the mold release has not started, so that the entire surface of the first base material 1 is in contact with the mold 7 via the first resin layer, so that the adhesion is strong. In the mold 7 used in the present invention, the average surface roughness of the final ring zone located at the position farthest from the center of the mold is set as the maximum value. Therefore, the first resin layer (not shown) has the lowest mold release force in the final ring zone and is the easiest to release. Therefore, in the first resin layer, the peripheral edge where the final ring zone is located tends to be the starting point of mold release. The average surface roughness of the preferred final ring zone is 10 nm or more.

ここで、離型の方法は特に限定されない。離型の方法としては、第１基材１の端部をイジェクタで押し上げる方法が一般的である。また、第１基材１の型７とは反対側の面に冷却ガスを噴霧して、第１基材１の上下間に温度差を付けることによって第１基材１に反りを発生させて離型し、その後イジェクタで押し上げる方法を用いても良い。 Here, the mold release method is not particularly limited. As a method of releasing the mold, a method of pushing up the end portion of the first base material 1 with an ejector is common. Further, the surface of the first base material 1 opposite to the mold 7 is sprayed with a cooling gas to create a temperature difference between the upper and lower sides of the first base material 1 to cause the first base material 1 to warp. A method of releasing the mold and then pushing it up with an ejector may be used.

図５（ｂ）は、第１基材１が型７の端部から剥離を開始した状態を示す。破線で示した形状１０１は型の平均表面粗さが一定のとき基材の形状を示している。一方、実線１は、本発明の型を用いた時の基材の形状を示しており、点線は実線の位置に移動する前の本発明の型を用いた時の基材の形状を示している。 FIG. 5B shows a state in which the first base material 1 starts peeling from the end portion of the mold 7. The shape 101 shown by the broken line indicates the shape of the base material when the average surface roughness of the mold is constant. On the other hand, the solid line 1 shows the shape of the base material when the mold of the present invention is used, and the dotted line shows the shape of the base material when the mold of the present invention is used before moving to the position of the solid line. There is.

図５（ｃ）は、図５（ｂ）の状態から第１基材１を端部から押し上げることによって、型７の中間輪帯から第１樹脂層３の剥離を進展させている状態を示す。ここで、型７の中間輪帯の斜面７１の平均表面粗さは最外斜面から剥離が進行する方向（型の中心に向かう方向）に向かって、連続的もしくは断続的に小さくなっている。そのため、第１基材１の端部を押し上げるにつれて、第１樹脂層３は離型力が高くなる。すなわち、第１基材１の端部を押し上げるにつれて第１樹脂層３は型７から剥離しづらくなり、第１基材１と型７との密着径が小さくなりすぎず、第１基材１の曲率半径を徐々に大きくすることができる。そのため、回折光学素子のフレアを低減するために、格子角度を小さく設計しても、離型し易い構造となる。一方、この段階で曲率半径が小さすぎると、剥離に際し型が格子と衝突し、格子欠損が起きやすくなる。 FIG. 5C shows a state in which the first resin layer 3 is peeled off from the intermediate ring zone of the mold 7 by pushing up the first base material 1 from the end portion from the state of FIG. 5B. .. Here, the average surface roughness of the slope 71 of the intermediate ring zone of the mold 7 is continuously or intermittently reduced from the outermost slope in the direction in which the peeling proceeds (direction toward the center of the mold). Therefore, as the end portion of the first base material 1 is pushed up, the mold release force of the first resin layer 3 increases. That is, as the end portion of the first base material 1 is pushed up, the first resin layer 3 becomes harder to peel off from the mold 7, the contact diameter between the first base material 1 and the mold 7 does not become too small, and the first base material 1 does not become too small. The radius of curvature of can be gradually increased. Therefore, in order to reduce the flare of the diffractive optical element, even if the lattice angle is designed to be small, the structure is easy to release. On the other hand, if the radius of curvature is too small at this stage, the mold collides with the lattice during peeling, and lattice defects are likely to occur.

図５（ｄ）は、第１基材１が型７から剥離し、第１基材の中間輪帯から最小輪帯まで剥離を進展させている状態を示す。この状態では、第１基材１の曲率半径が大きいまま剥離を進展させるため、平均表面粗さが一定で曲率半径が十分に大きくならない型を用いた時よりも、格子に欠損が生じにくい。好ましい最小輪帯の平均表面粗さは５ｎｍ以下である。第１基材１はガラスであるため、曲率半径が大きいまま剥離を続けて離型させてしまうと、第１基材１に割れが生じるおそれがあるため、最小輪帯は第１輪帯より周縁側に位置している。 FIG. 5D shows a state in which the first base material 1 is peeled from the mold 7 and the peeling is progressing from the intermediate ring zone to the minimum ring zone of the first base material. In this state, since peeling progresses while the radius of curvature of the first base material 1 is large, defects are less likely to occur in the lattice than when a mold having a constant average surface roughness and a radius of curvature that is not sufficiently large is used. The average surface roughness of the preferred minimum ring zone is 5 nm or less. Since the first base material 1 is glass, if the first base material 1 is continuously peeled and released while the radius of curvature is large, the first base material 1 may be cracked. Therefore, the minimum ring zone is larger than the first ring band. It is located on the peripheral side.

図５（ｅ）は、第１基材１を型７から完全に剥離させるときの状態を示す図である。これは、この状態では剥離させるために必要な力の方向が、これまでの工程と異なり上向きである。そのため、図５（ａ）〜（ｄ）で説明した剥離させるために必要な力の方向が斜め方向である状態より、離型に必要な力が大きい。ここで第１輪帯の斜面の平均表面粗さは、最小輪帯より大きく、かつ、最終輪帯よりは小さい。第１輪帯の斜面の平均表面粗さが最小輪帯より大きくすることにより、型から樹脂が剥離しやすくしている。また、第１輪帯の斜面の平均表面粗さを最終輪帯より大きくせず、第１輪帯が剥離の起点にならないようにしている。好ましい第１輪帯の平均表面粗さは、最小輪帯の平均表面粗さＲｍｉｎの２倍以上である。以上が離型工程である。 FIG. 5 (e) is a diagram showing a state when the first base material 1 is completely peeled from the mold 7. This is because, in this state, the direction of the force required for peeling is upward unlike the conventional steps. Therefore, the force required for mold release is larger than the state in which the direction of the force required for peeling described in FIGS. 5A to 5D is an oblique direction. Here, the average surface roughness of the slope of the first ring zone is larger than that of the smallest ring zone and smaller than that of the final ring zone. By making the average surface roughness of the slope of the first ring zone larger than that of the minimum ring zone, the resin can be easily peeled off from the mold. Further, the average surface roughness of the slope of the first wheel zone is not made larger than that of the final wheel band so that the first wheel band does not become the starting point of peeling. The preferred average surface roughness of the first ring zone is at least twice the average surface roughness Rmin of the smallest ring zone. The above is the mold release process.

なお、型７の最小輪帯の位置は、型の斜面の総面積を１００面積％、型の中心を始点として最終輪帯に向かう方向に、１０面積パーセント以上２０面積パーセント以下の範囲に位置することが好ましい。最小輪帯が型の中心から１０面積パーセント未満の位置にあると、第１基材１が型７と密着している面積がわずかになるまで第１基材１が変形を続けて反るため、イジェクタで完全に離型する際に反力を受けて第１樹脂層３に欠けが生じるおそれがある。また、第１基材１に割れが発生する可能性も高くなる。一方、最小輪帯が２０面積パーセントより大きい位置にあると、イジェクタで完全に離型する際に第１樹脂層３と型７が密着している面積が大きい。そのため離型の際に大きな力が必要となるため好ましくない。 The position of the minimum ring zone of the mold 7 is located in the range of 10 area% or more and 20 area% or less in the direction from the center of the mold to the final ring zone with the total area of the slope of the mold being 100 area%. Is preferable. If the minimum ring zone is located less than 10 area percent from the center of the mold, the first base material 1 will continue to deform and warp until the area where the first base material 1 is in close contact with the mold 7 becomes small. When the ejector completely releases the mold, the first resin layer 3 may be chipped due to the reaction force. In addition, there is a high possibility that the first base material 1 will be cracked. On the other hand, when the minimum ring zone is located at a position larger than 20 area percent, the area where the first resin layer 3 and the mold 7 are in close contact with each other when the mold is completely released by the ejector is large. Therefore, a large force is required at the time of mold release, which is not preferable.

（接合工程）
図６は本発明の回折光学素子の一実施態様を示す図であり、第２樹脂層を形成する接合工程を示す図である。 (Joining process)
FIG. 6 is a diagram showing an embodiment of the diffractive optical element of the present invention, and is a diagram showing a bonding step for forming a second resin layer.

まず、図６（ａ）のように第２樹脂層の前駆体である第２樹脂１１の接合層として必要な量を第２基材２にディスペンサーを使用して滴下する。なお、第２樹脂１１を滴下する前には必要に応じて成形した格子を破損しない程度で洗浄して、接合工程前にパーティクルを除去しておくことが好ましい。 First, as shown in FIG. 6A, an amount required as a bonding layer of the second resin 11, which is a precursor of the second resin layer, is dropped onto the second base material 2 using a dispenser. Before dropping the second resin 11, it is preferable to wash the formed lattice as necessary to the extent that the formed lattice is not damaged to remove particles before the joining step.

また、図６（ｂ）のように第２樹脂１１は第１樹脂層３の上にも滴下することが好ましい。接合に必要な第２樹脂１１を第２基材２と第１樹脂層３に分けて滴下することにより、貼り合わせの際、樹脂に泡が混入するのを防ぐことができる。液体−固体の接触に比べて液体同士の接触は泡の混入リスクが小さく出来るためである。 Further, as shown in FIG. 6B, it is preferable that the second resin 11 is also dropped onto the first resin layer 3. By dividing the second resin 11 required for bonding into the second base material 2 and the first resin layer 3 and dropping them, it is possible to prevent bubbles from being mixed into the resin during bonding. This is because the risk of foam contamination can be reduced in the contact between liquids as compared with the contact between liquids and solids.

続いて、図６（ｃ）、図６（ｄ）のように、第２樹脂１１を滴下した第２基材２と第１樹脂層３を近づけて接液する。 Subsequently, as shown in FIGS. 6 (c) and 6 (d), the second base material 2 to which the second resin 11 is dropped and the first resin layer 3 are brought into close contact with each other.

続いて、図６（ｅ）のように、加圧用ガラス８を第１基材１の上面に設置した状態で２枚の成形レンズ１０を加圧して、第２樹脂の充填を完了する。 Subsequently, as shown in FIG. 6E, the two molded lenses 10 are pressurized with the pressurizing glass 8 placed on the upper surface of the first base material 1, to complete the filling of the second resin.

その後、図６（ｆ）のように、第２樹脂１１に紫外線光源９から紫外線を照射して硬化させて、第１樹脂層３の上に第２樹脂層４を形成し、回折光学素子を得る。 Then, as shown in FIG. 6 (f), the second resin 11 is irradiated with ultraviolet rays from the ultraviolet light source 9 to be cured to form the second resin layer 4 on the first resin layer 3, and the diffractive optical element is formed. obtain.

なお、上述した製造方法によって得られた回折光学素子は第２基材２を有しているが、図６（ｆ）の工程の後に第２基材２は、離型しても構わない。得られる回折光学素子の光学性能に大きな差が生じないためである。 Although the diffractive optical element obtained by the above-mentioned manufacturing method has the second base material 2, the second base material 2 may be released after the step of FIG. 6 (f). This is because there is no big difference in the optical performance of the obtained diffractive optical element.

以上、本発明の回折光学素子の製造方法によれば、格子欠損が無い事でフレアが低減され、更に樹脂層間の剥離が抑制された回折光学素子を提供できる。 As described above, according to the method for manufacturing a diffractive optical element of the present invention, it is possible to provide a diffractive optical element in which flare is reduced and peeling between resin layers is suppressed because there is no lattice defect.

（撮像装置）
図７は、本発明の撮像装置の好適な実施形態の一例であり、本発明の光学機器の一例であるレンズ鏡筒（交換レンズ）が結合された一眼レフデジタルカメラの構成を示している。 (Imaging device)
FIG. 7 shows an example of a preferred embodiment of the image pickup apparatus of the present invention, and shows a configuration of a single-lens reflex digital camera to which a lens barrel (interchangeable lens), which is an example of the optical device of the present invention, is coupled.

本発明の光学機器とは、双眼鏡、顕微鏡、半導体露光装置、交換レンズ等、本発明の回折光学素子を含む光学系を備える機器のことをいう。あるいは本発明の回折光学素子を通過した光によって画像を生成する機器のことをいう。 The optical device of the present invention refers to a device including an optical system including the diffractive optical element of the present invention, such as binoculars, a microscope, a semiconductor exposure apparatus, and an interchangeable lens. Alternatively, it refers to a device that generates an image by light passing through the diffractive optical element of the present invention.

また、本発明の撮像装置とは、デジタルスチルカメラやデジタルビデオカメラ等のカメラシステムや、携帯電話機等の本発明の回折光学素子を通過した光を受光する撮像素子を備える電子機器のことをいう。なお、電子機器に搭載されるモジュール状の形態、例えばカメラモジュールを撮像装置とする場合もある。 The imaging device of the present invention refers to an electronic device including a camera system such as a digital still camera or a digital video camera, or an imaging element that receives light that has passed through the diffractive optical element of the present invention such as a mobile phone. .. In some cases, a modular form mounted on an electronic device, for example, a camera module may be used as an image pickup device.

図７において、カメラ本体６０２と光学機器であるレンズ鏡筒６０１とが結合されているが、レンズ鏡筒６０１はカメラ本体６０２対して着脱可能ないわゆる交換レンズである。 In FIG. 7, the camera body 602 and the lens barrel 601 which is an optical device are coupled, and the lens barrel 601 is a so-called interchangeable lens that can be attached to and detached from the camera body 602.

被写体からの光は、レンズ鏡筒６０１の筐体内（筐体６２０内）の撮影光学系の光軸上に配置された複数のレンズ６０３、６０５などからなる光学系を通過し、撮像素子に受光される。本発明の回折光学素子は例えば、レンズ６０５に用いることができる。 The light from the subject passes through an optical system composed of a plurality of lenses 603, 605 and the like arranged on the optical axis of the photographing optical system in the housing (inside the housing 620) of the lens barrel 601 and is received by the image sensor. Will be done. The diffractive optical element of the present invention can be used, for example, in the lens 605.

ここで、レンズ６０５は内筒６０４によって支持されて、フォーカシングやズーミングのためにレンズ鏡筒６０１の外筒に対して可動支持されている。 Here, the lens 605 is supported by the inner cylinder 604 and is movably supported with respect to the outer cylinder of the lens barrel 601 for focusing and zooming.

撮影前の観察期間では、被写体からの光は、カメラ本体の筐体６２１内の主ミラー６０７により反射され、プリズム６１１を透過後、ファインダレンズ６１２を通して撮影者に撮影画像が映し出される。主ミラー６０７は例えばハーフミラーとなっており、主ミラーを透過した光はサブミラー６０８によりＡＦ（オートフォーカス）ユニット６１３の方向に反射され、例えばこの反射光は測距に使用される。また、主ミラー６０７は主ミラーホルダ６４０に接着などによって装着、支持されている。不図示の駆動機構を介して、撮影時には主ミラー６０７とサブミラー６０８を光路外に移動させ、シャッタ６０９を開き、撮像素子６１０にレンズ鏡筒６０１から入射した撮影光像を結像させる。また、絞り６０６は、開口面積を変更することにより撮影時の明るさや焦点深度を変更できるよう構成される。 During the observation period before shooting, the light from the subject is reflected by the main mirror 607 in the housing 621 of the camera body, passes through the prism 611, and then the shot image is projected to the photographer through the finder lens 612. The main mirror 607 is, for example, a half mirror, and the light transmitted through the main mirror is reflected by the sub mirror 608 in the direction of the AF (autofocus) unit 613. For example, this reflected light is used for distance measurement. Further, the main mirror 607 is attached and supported on the main mirror holder 640 by adhesion or the like. At the time of photographing, the main mirror 607 and the sub mirror 608 are moved out of the optical path via a drive mechanism (not shown), the shutter 609 is opened, and the image pickup element 610 is imaged with a photographed light image incident on the lens barrel 601. Further, the aperture 606 is configured so that the brightness and the depth of focus at the time of shooting can be changed by changing the aperture area.

まず、実施例で作成した回折光学素子の評価方法を説明する。 First, an evaluation method of the diffractive optical element produced in the examples will be described.

（フレア率）
フレアの測定は、回折効率（入射した光に対する割合）を算出することにより求めた。１次回折光を使用する設計として、有効画素内で結像してしまう０次光と２次光（不要光）を合わせた回折効率を測定し、それをフレア率とした。 (Flare rate)
The flare was measured by calculating the diffraction efficiency (ratio to the incident light). As a design using the first-order diffracted light, the diffraction efficiency of the combination of the 0th-order light and the second-order light (unwanted light) that form an image in the effective pixel was measured, and this was used as the flare rate.

具体的には、作成した回折光学素子の格子間隔が１００（μｍ）となる領域に光軸方向から回折光学素子に光を入射させて、回折光の出射側に０次、２次の回折光のみを通過させるスリットを配して、分光光度計で光量を測定することにより算出した。なお、測定の精度を保証するため、測定は温度２３±０．５℃、湿度５０±１０％の環境下で実施した。 Specifically, light is incident on the diffractive optical element from the optical axis direction in a region where the lattice spacing of the created diffractive optical element is 100 (μm), and 0th-order and second-order diffracted light is emitted on the emission side of the diffracted light. It was calculated by arranging a slit through which only the light passes and measuring the amount of light with a spectrophotometer. In order to guarantee the accuracy of the measurement, the measurement was carried out in an environment of a temperature of 23 ± 0.5 ° C. and a humidity of 50 ± 10%.

（型の斜面の平均表面粗さ）
製造に用いた型の斜面の平均表面粗さは、原子間力顕微鏡（ＡＦＭ）を用いて測定した。 (Average surface roughness of the slope of the mold)
The average surface roughness of the slope of the mold used in the production was measured using an atomic force microscope (AFM).

（第１樹脂層の斜面の平均表面粗さ）
製造した回折光学素子の第１樹脂層の斜面の平均表面粗さは、まず、回折光学素子の積層方向に対し中心を通るように切断し、その切断面を有するサンプルを作成した。作成したサンプルを薄片化し、走査型透過電子顕微鏡（ＳＴＥＭ）を用いて測定した。 (Average surface roughness of the slope of the first resin layer)
The average surface roughness of the slope of the first resin layer of the manufactured diffractive optical element was first cut so as to pass through the center with respect to the stacking direction of the diffractive optical element, and a sample having the cut surface was prepared. The prepared sample was sliced and measured using a scanning transmission electron microscope (STEM).

（高温高湿耐久試験）
得られた回折光学素子を温度６０℃、湿度７０％に設定した恒温槽に１２００時間放置し、その後室温に２４時間放置した。 (High temperature and high humidity durability test)
The obtained diffractive optical element was left in a constant temperature bath set at a temperature of 60 ° C. and a humidity of 70% for 1200 hours, and then left at room temperature for 24 hours.

次に、実施例を挙げて本発明の回折光学素子およびその製造方法を具体的に説明する。 Next, the diffractive optical element of the present invention and a method for manufacturing the same will be specifically described with reference to examples.

（実施例１）
図４〜６で説明した製造方法で密着２層型の回折光学素子を製造した。第１基材１には、硝材（株式会社オハラ製、商品名：Ｓ−ＦＰＬ）を球面形状に加工（成形面が曲率半径Ｒ２００で凸形状、反対側の面がＲ１５０）した直径５８ｍｍのものを用いた。レプリカ成形する側の面には樹脂との密着性を高める目的でカップリング処理を施した。カップリング液は、３−メタクリロキシプロピルトリメトキシシラン（信越化学工業株式会社製、商品名：ＫＢＭ５０３）を水とエタノールの混合液（水１０％）に濃度５％で溶かし、ｐＨ調整として酢酸を０．５％添加したものを使用した。このカップリング液をスプレーコーターで塗布し、１００℃のオーブン内で１時間の脱水乾燥処理をした。反対側の面にはＳｉＯ_２とＳｉＯで構成される反射防止膜を成膜した。 (Example 1)
The close contact two-layer diffractive optical element was manufactured by the manufacturing method described in FIGS. 4 to 6. The first base material 1 has a diameter of 58 mm obtained by processing a glass material (manufactured by OHARA Corporation, trade name: S-FPL) into a spherical shape (the molded surface has a radius of curvature R200 and a convex shape, and the opposite surface is R150). Was used. The surface on the replica molding side was subjected to a coupling treatment for the purpose of improving the adhesion with the resin. As the coupling solution, 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM503) is dissolved in a mixed solution of water and ethanol (water 10%) at a concentration of 5%, and acetic acid is added as a pH adjustment. The one to which 0.5% was added was used. This coupling liquid was applied with a spray coater and dehydrated and dried in an oven at 100 ° C. for 1 hour. An antireflection film composed of SiO ₂ and SiO was formed on the opposite surface.

型７はステンレス鋼（ウッデホルム株式会社製、商品名：ＳＴＡＶＡＸ）の土台にＮｉＰを２００μｍメッキしたものを切削加工機で鋸歯断面形状に加工したものを使用し、実施例１の回折光学素子の輪帯数は１１０、格子角度は８１°となるよう設計した。また、各輪帯における型の斜面の平均表面粗さは以下のように設計した。 As the mold 7, a stainless steel (manufactured by Woodeholm Co., Ltd., trade name: STAVAX) base plated with NiP of 200 μm and processed into a sawtooth cross-sectional shape by a cutting machine is used, and the ring of the diffraction optical element of Example 1 is used. It was designed so that the number of bands was 110 and the lattice angle was 81 °. In addition, the average surface roughness of the slope of the mold in each ring zone was designed as follows.

第１輪帯〜第９輪帯：１０ｎｍ、第１０輪帯〜第１８輪帯：４ｎｍ、第１９輪帯〜第３８輪帯：５ｎｍ、第３９輪帯〜第４９輪帯：６ｎｍ、第５０輪帯〜第７２輪帯：８ｎｍ、第７３輪帯〜第９８輪帯：１０ｎｍ、第９９輪帯〜第１１０輪帯：１８ｎｍ。 1st wheel band to 9th wheel band: 10 nm, 10th wheel band to 18th wheel band: 4 nm, 19th wheel band to 38th wheel band: 5 nm, 39th wheel band to 49th wheel band: 6 nm, 50th Ring band to 72nd wheel band: 8 nm, 73rd wheel band to 98th wheel band: 10 nm, 99th wheel band to 110th wheel band: 18 nm.

ここで、平均表面粗さを最小値４ｎｍで調整した第１９輪帯から第３８輪帯は、第１樹脂層が形成される領域の中心から最終輪帯に向かって１０面積％から２０面積％の位置に相当する。 Here, in the 19th to 38th ring zones in which the average surface roughness is adjusted to a minimum value of 4 nm, 10 area% to 20 area% from the center of the region where the first resin layer is formed toward the final ring zone. Corresponds to the position of.

次いで、第１樹脂６として、ウレタン変性ポリエステルアクリレートを主成分としたものに光反応開始剤（日本チバガイギー株式会社製、商品名Ｉｒｇａｃｕｒｅ１８４）を用意した。この材料に酸化インジウム錫微粒子を分散させた紫外線硬化型樹脂５０ｍｇを、ディスペンサー（武蔵エンジニアリング株式会社製、商品名：ＭＥＡＳＵＲＩＮＧ ＭＡＳＴＥＲ ＭＰＰ−１）を使用して第１基材１に滴下した。その後、加圧用ガラス８を用いて、ゆっくりと第１基材１を下降させ、第１樹脂６を光学有効部外まで押し拡げた。 Next, as the first resin 6, a photoreaction initiator (manufactured by Ciba-Geigy Japan Co., Ltd., trade name Irgacure 184) was prepared with a urethane-modified polyester acrylate as a main component. 50 mg of an ultraviolet curable resin in which indium tin oxide fine particles were dispersed in this material was added dropwise to the first substrate 1 using a dispenser (manufactured by Musashi Engineering Co., Ltd., trade name: MEASURING MASTER MPP-1). Then, using the pressurizing glass 8, the first base material 1 was slowly lowered, and the first resin 6 was pushed out to the outside of the optically effective portion.

その状態で、加圧用ガラス８と第１基材１を通して第１樹脂６に紫外線を照射して、第１基材上に第１樹脂層３を形成した。紫外線の照射には紫外線照射装置（ＨＯＹＡ ＣＡＮＤＥＯ ＯＰＴＲＯＮＩＣＳ 社製、商品名：ＵＶ光源ＵＬ７５０）を使用し、その照射量は１５Ｊ／ｃｍ^２（１５ｍＷ／ｃｍ^２の照度で１０００秒照射）とした。照射終了後に第１樹脂層が形成された第１基材１に、型７とは反対側から液体窒素を噴霧ノズルから噴霧して第１基材１を反らせると共に、下側からはイジェクタピンを上昇させて反り戻りを防止して型７からの離型を完了させ、成形レンズ１０を得た。得られた成形レンズ１０の第１樹脂層３の回折格子を光学顕微鏡で観察して、格子欠損の発生状況を確認したが、全１１０輪帯で格子欠損は確認されなかった。 In that state, the first resin 6 was irradiated with ultraviolet rays through the pressurizing glass 8 and the first base material 1, to form the first resin layer 3 on the first base material. An ultraviolet irradiation device (manufactured by HOYA CANDEO OPTRONICS, trade name: UV light source UL750) was used for ultraviolet irradiation, and the irradiation amount was 15 J / cm ² (irradiation at an illuminance of 15 mW / cm ² for 1000 seconds). Liquid nitrogen is sprayed from the side opposite to the mold 7 onto the first base material 1 on which the first resin layer is formed after the irradiation is completed to warp the first base material 1, and the ejector pin is applied from the lower side. The molding lens 10 was obtained by raising the mold to prevent warping and completing the mold release from the mold 7. The diffraction grating of the first resin layer 3 of the obtained molded lens 10 was observed with an optical microscope to confirm the occurrence of lattice defects, but no lattice defects were confirmed in all 110 ring bands.

次いで、第２樹脂１１として、ウレタン変性ポリエステルアクリレートを主成分としたものに光反応開始剤（日本チバガイギー株式会社製、商品名：Ｉｒｇａｃｕｒｅ１８４）及び二酸化ジルコニア微粒子を分散させた紫外線硬化型樹脂を用意した。これらを微量吐出ディスペンサー（エンジニアリングシステム株式会社製、商品名：高精度ディスペンサーＲ−ｊｅｔ）を使用して、第２基材２との接合に必要な樹脂量のうちの３６２ｍｇを滴下した。 Next, as the second resin 11, an ultraviolet curable resin in which a photoreaction initiator (manufactured by Ciba-Geigy Japan Co., Ltd., trade name: Irgacure184) and zirconia dioxide fine particles were dispersed in a urethane-modified polyester acrylate as a main component was prepared. .. Using a small amount discharge dispenser (manufactured by Engineering System Co., Ltd., trade name: high-precision dispenser R-jet), 362 mg of the amount of resin required for bonding to the second base material 2 was added dropwise.

続いて、同じ微量吐出ディスペンサーを使用して第１樹脂層３の中心部（第１及び第２輪帯内）に樹脂残量３．０ｍｇを滴下した。第２基材２は、硝材（株式会社オハラ製、商品名：Ｓ−ＬＡＨ５５）を球面形状に加工（成形面は曲率半径Ｒ２００で凹形状、反対側の面はＲ３００に設計）した直径６２ｍｍのものを用いた。第２基材２は、第１基材１と同様にレプリカを形成する側の面には樹脂との密着性を高める目的でカップリング処理を施した。また、反対側の面にはＳｉＯ_２とＳｉＯで構成される反射防止膜を成膜した。 Subsequently, using the same trace amount discharge dispenser, 3.0 mg of the remaining amount of resin was dropped onto the central portion (inside the first and second wheel bands) of the first resin layer 3. The second base material 2 has a diameter of 62 mm obtained by processing a glass material (manufactured by OHARA Corporation, trade name: S-LAH55) into a spherical shape (the molded surface is concave with a radius of curvature R200, and the opposite surface is designed to be R300). I used the one. Similar to the first base material 1, the surface of the second base material 2 on the side where the replica is formed is subjected to a coupling treatment for the purpose of improving the adhesion with the resin. An antireflection film composed of SiO ₂ and SiO was formed on the opposite surface.

その後、第２樹脂層４および第２基材２を貼り合わせ装置内で接合した。この装置は第２基材２（凹形状）を下側に配置して固定し、成形レンズ１０（凸形状）を逆向きにして第２基材２に一定速度で近づけるものである。第１樹脂層と第２基材２との間には６０μｍ厚のＳＵＳ製スペーサーを挿入した。成形レンズ１０を下降速度０．１ｍｍ／秒で第２基材２に近付け、完全に接液した後で加圧用ガラスを用いて、一定圧力（１０ｋｇｆ）を加えてスペーサーに突き当たるまで下降させた。第２樹脂１１が完全に第１樹脂層３と第２基材２との間に充填され、第２樹脂１１の反発力が無くなった後、スペーサーと加圧ガラスを取り除いた。その状態で紫外線を照射して充填された第２樹脂１１を硬化させて、密着２層型の回折光学素子２０を得た。紫外線照射装置は上記と同様のＵＬ７５０を使用し、紫外線の照射量は３２Ｊ／ｃｍ^２とした。 Then, the second resin layer 4 and the second base material 2 were bonded in the bonding device. In this device, the second base material 2 (concave shape) is arranged and fixed on the lower side, and the molded lens 10 (convex shape) is turned upside down to approach the second base material 2 at a constant speed. A 60 μm-thick SUS spacer was inserted between the first resin layer and the second base material 2. The molded lens 10 was brought close to the second base material 2 at a lowering speed of 0.1 mm / sec, and after being completely contacted with the liquid, a constant pressure (10 kgf) was applied to lower the molded lens 10 until it hits the spacer. After the second resin 11 was completely filled between the first resin layer 3 and the second base material 2 and the repulsive force of the second resin 11 disappeared, the spacer and the pressurized glass were removed. In that state, the filled second resin 11 was cured by irradiating with ultraviolet rays to obtain a close contact two-layer diffractive optical element 20. As the ultraviolet irradiation device, UL750 similar to the above was used, and the irradiation amount of ultraviolet rays was 32 J / cm ² .

この回折光学素子を撮像光学系に組み込んで、フレアの測定を行った。測定の結果、実施例１の回折光学素子としてのフレア率は０．４％であった。 This diffractive optical element was incorporated into an imaging optical system to measure flare. As a result of the measurement, the flare rate as the diffractive optical element of Example 1 was 0.4%.

この回折光学素子に対して高温高湿耐久試験を実施したところ、耐久前後での光学特性に変化は認められず、光学素子の外観も周縁部での剥がれ等の変化は認められなかった。 When a high-temperature and high-humidity durability test was carried out on this diffractive optical element, no change was observed in the optical characteristics before and after the durability, and no change in the appearance of the optical element such as peeling at the peripheral portion was observed.

この回折光学素子の直径で半分に切断した断面方向から輪帯の接合界面を観察したところ、第１樹脂層の平均表面粗さは金型の平均表面粗さを精度良く転写していることが確認された。 When observing the bonding interface of the annulus from the cross-sectional direction cut in half with the diameter of this diffractive optical element, it was found that the average surface roughness of the first resin layer accurately transferred the average surface roughness of the mold. confirmed.

（実施例２）
実施例２は実施例１と型７の形状が異なる。具体的には、輪帯数１１０であるが、格子角度が８４°であり、実施例１と比べて離型し易い形状となっている。また、各輪帯における型の斜面の平均表面粗さは以下のように設計した。 (Example 2)
The shape of the mold 7 of the second embodiment is different from that of the first embodiment. Specifically, although the number of ring bands is 110, the lattice angle is 84 °, and the shape is easier to release than that of the first embodiment. In addition, the average surface roughness of the slope of the mold in each ring zone was designed as follows.

第１輪帯〜第４輪帯：１０ｎｍ、第５輪帯〜第１０輪帯：８ｎｍ、第１１輪帯〜第１５輪帯：４ｎｍ、第１６輪帯〜第２８輪帯：６ｎｍ、第２９輪帯〜第４９輪帯：８ｎｍ、５０輪帯〜第７２輪帯：１２ｎｍ、第７３輪帯〜第９８輪帯：１６ｎｍ、第９９輪帯〜第１１０輪帯：２０ｎｍ。 1st wheel band to 4th wheel band: 10 nm, 5th wheel band to 10th wheel band: 8 nm, 11th wheel band to 15th wheel band: 4 nm, 16th wheel band to 28th wheel band: 6 nm, 29th Ring band to 49th wheel band: 8 nm, 50 ring band to 72 wheel band: 12 nm, 73rd wheel band to 98th wheel band: 16 nm, 99th wheel band to 110th wheel band: 20 nm.

実施例１と比べて、離型し易く格子欠損が抑制される形状のため、型の平均表面粗さを実施例１より大きくして、離型力を低減させた。 Since the shape is easier to release and suppresses lattice defects as compared with Example 1, the average surface roughness of the mold is made larger than that of Example 1 to reduce the mold release force.

ここで、平均表面粗さを最小値８ｎｍで調整した第１１輪帯から第１５輪帯は、第１樹脂層が形成される領域の中心から周縁に向かって１２面積％から１７面積％の位置に相当する。 Here, the 11th to 15th ring zones having the average surface roughness adjusted to a minimum value of 8 nm are located at positions of 12 area% to 17 area% from the center of the region where the first resin layer is formed toward the peripheral edge. Corresponds to.

離型は、第１基材１の端部を位置制御可能なイジェクタで順次押し上げる方法で行った。得られた成形レンズ１０を光軸方向から光学顕微鏡で観察して、格子欠損の発生状況を確認したが、全１１０輪帯で格子欠損は確認されなかった。 The mold release was performed by a method of sequentially pushing up the end portion of the first base material 1 with a position-controllable ejector. The obtained molded lens 10 was observed with an optical microscope from the direction of the optical axis to confirm the occurrence of lattice defects, but no lattice defects were confirmed in all 110 ring bands.

次いで、実施例１と同様の方法で、得られた成形レンズ１０と第２基材２を貼り合わせ装置内で接合して密着２層型の回折光学素子を得た。 Then, in the same manner as in Example 1, the obtained molded lens 10 and the second base material 2 were joined in a bonding device to obtain a close contact two-layer diffractive optical element.

実施例２の回折光学素子を撮像光学系に組み込んで、フレアの測定を行った。測定の結果、実施例２のフレア率は０．４６％であった。 The diffractive optical element of Example 2 was incorporated into the imaging optical system, and flare was measured. As a result of the measurement, the flare rate of Example 2 was 0.46%.

この回折光学素子に対して高温高湿耐久試験を実施したところ、耐久前後での光学特性に変化は認められず、光学素子の外観も周縁部での剥がれ等の変化は認められなかった。 When a high-temperature and high-humidity durability test was carried out on this diffractive optical element, no change was observed in the optical characteristics before and after the durability, and no change in the appearance of the optical element such as peeling at the peripheral portion was observed.

この回折光学素子の直径で半分に切断した断面方向から輪帯の接合界面を観察したところ、第１樹脂層の平均表面粗さは金型の平均表面粗さを精度良く転写していることが確認された。 When observing the bonding interface of the annulus from the cross-sectional direction cut in half with the diameter of this diffractive optical element, it was found that the average surface roughness of the first resin layer accurately transferred the average surface roughness of the mold. confirmed.

（実施例３）
実施例３は実施例２と型７の形状が異なる。具体的には、各輪帯における型の斜面の平均表面粗さが異なる。切削加工機のステージの回転速度を徐々に変化させ、中心から周縁部に向かって平均表面粗さが連続的に変化するようにした。実施例３に用いた型７の斜面の平均表面粗さは、以下のとおりである。 (Example 3)
The shape of the mold 7 of the third embodiment is different from that of the second embodiment. Specifically, the average surface roughness of the slope of the mold in each ring zone is different. The rotation speed of the stage of the cutting machine was gradually changed so that the average surface roughness changed continuously from the center to the peripheral edge. The average surface roughness of the slope of the mold 7 used in Example 3 is as follows.

第１輪帯〜第１０輪帯：１０ｎｍから８ｎｍ、第１１輪帯〜第１５輪帯：８ｎｍから４ｎｍ、第１６輪帯〜第７２輪帯：４ｎｍから１２ｎｍ、第７３輪帯〜第１１０輪帯：１２ｎｍから２０ｎｍ。 1st wheel band to 10th wheel band: 10 nm to 8 nm, 11th wheel band to 15th wheel band: 8 nm to 4 nm, 16th wheel band to 72nd wheel band: 4 nm to 12 nm, 73rd wheel band to 110th wheel Band: 12 nm to 20 nm.

ここで平均表面粗さの最小値４ｎｍで調整した第１５、１６輪帯は、第１樹脂層が形成される領域の中心から周縁に向かって１５面積％の位置に相当する。 Here, the 15th and 16th ring zones adjusted with the minimum value of 4 nm of the average surface roughness correspond to the positions of 15 area% from the center of the region where the first resin layer is formed toward the peripheral edge.

また、第１樹脂６としてトリシクロデカンジメタノールジアクリレートに、ジ（２−メルカプトジエチル）スルフィドを付加反応させたものに光反応開始剤（日本チバガイギー株式会社製、商品名Ｉｒｇａｃｕｒｅ１８４）を添加したものを用意した。すなわち、実施例３の第１樹脂は硫黄を含有する材料であり、硫黄を含有しない材料よりも離型が難しい材料である。これ以外は実施例２と同様の方法で成形レンズ１０を作成した。 Further, as the first resin 6, a photoreaction initiator (manufactured by Ciba-Geigy Japan Co., Ltd., trade name Irgacure 184) is added to a tricyclodecanedimethanol diacrylate to which di (2-mercaptodiethyl) sulfide is added and reacted. Prepared. That is, the first resin of Example 3 is a material containing sulfur, which is more difficult to release than a material not containing sulfur. A molded lens 10 was produced in the same manner as in Example 2 except for this.

得られた成形レンズ１０を光軸方向から光学顕微鏡で観察して、格子欠損の発生状況を確認したが、全１１０輪帯で格子欠損は確認されなかった。 The obtained molded lens 10 was observed with an optical microscope from the direction of the optical axis to confirm the occurrence of lattice defects, but no lattice defects were confirmed in all 110 ring bands.

また、実施例３では第２樹脂１１として、フッ素含有アクリレートとフルオレン基含有アリレートを反応させたものに光反応開始剤（Ｉｒｇａｃｕｒｅ１８４）を添加させたものを用意した。それ以外は、実施例１と同様の方法で接合工程を行い、実施例３の回折光学素子を得た。 Further, in Example 3, as the second resin 11, a resin obtained by reacting a fluorine-containing acrylate with a fluorene group-containing allylate and adding a photoreaction initiator (Irgacure 184) was prepared. Other than that, the joining step was carried out in the same manner as in Example 1 to obtain the diffractive optical element of Example 3.

実施例３の回折光学素子を撮像光学系に組み込んで、フレアの測定を行った。測定の結果、実施例３のフレア率は０．４６％と実施例２と同じであった。 The diffractive optical element of Example 3 was incorporated into the imaging optical system, and flare was measured. As a result of the measurement, the flare rate of Example 3 was 0.46%, which was the same as that of Example 2.

この回折光学素子に対して高温高湿耐久試験を実施したところ、耐久前後での光学特性に変化は認められず、光学素子の外観も周縁部での剥がれ等の変化は認められなかった。 When a high-temperature and high-humidity durability test was carried out on this diffractive optical element, no change was observed in the optical characteristics before and after the durability, and no change in the appearance of the optical element such as peeling at the peripheral portion was observed.

この回折光学素子の直径で半分に切断した断面方向から輪帯の接合界面を観察したところ、第１樹脂層の平均表面粗さは金型の平均表面粗さを精度良く転写していることが確認された。 When observing the bonding interface of the annulus from the cross-sectional direction cut in half with the diameter of this diffractive optical element, it was found that the average surface roughness of the first resin layer accurately transferred the average surface roughness of the mold. confirmed.

（比較例１）
比較例１は、実施例１と用いた型７の形状が異なる。具体的には、輪帯数および格子角度は同じであるが、切削加工機のステージの回転速度を制御することで、格子斜面の平均表面粗さを全１１０輪帯で４ｎｍとなるように調整した。 (Comparative Example 1)
In Comparative Example 1, the shape of the mold 7 used is different from that of Example 1. Specifically, although the number of ring zones and the lattice angle are the same, the average surface roughness of the lattice slope is adjusted to 4 nm for all 110 ring zones by controlling the rotation speed of the stage of the cutting machine. did.

また、成形レンズ１０を得る際の離型は、実施例１と同様に液体窒素を噴霧することでレンズを反らせる冷却離型を行ったが、離型力が大きく十分な反りが得られなかったので、冷却とイジェクタピンを併用した離型を採用した。そのため、実施例１と比較して、周縁部で剥離が開始するまでに多くの時間を要した。 Further, the mold release at the time of obtaining the molded lens 10 was performed by cooling and releasing the lens by spraying liquid nitrogen in the same manner as in Example 1, but the mold release force was large and sufficient warpage could not be obtained. Therefore, we adopted a mold release that uses both cooling and ejector pins. Therefore, as compared with Example 1, it took a lot of time to start peeling at the peripheral portion.

比較例１の成形レンズ１０を光軸方向から光学顕微鏡で観察して、格子欠損の発生状況を確認したところ、素子の中心から中帯部（３０〜５０輪帯近傍）にかけて格子欠損が確認された。１つの輪帯内で周方向の１／６以上が欠損している輪帯は全１１０輪帯中１５輪帯に及んでいた。また回折格子の周縁部においても、周方向で１／６未満ではあったが、格子欠損が発生していた。 When the molded lens 10 of Comparative Example 1 was observed from the optical axis direction with an optical microscope to confirm the occurrence of lattice defects, lattice defects were confirmed from the center of the element to the middle zone (near the 30 to 50 ring zones). It was. In one ring zone, more than 1/6 in the circumferential direction was missing, covering 15 of the 110 ring zones. Also, at the peripheral portion of the diffraction grating, although it was less than 1/6 in the circumferential direction, lattice defects occurred.

その後、破損して第１樹脂層に付着した格子の切れ端を除去してから、実施例１と同様の方法で、得られた成形レンズ１０と第２基材２を貼り合わせ装置内で接合して密着２層型の回折光学素子を得た。 Then, after removing the broken pieces of the lattice attached to the first resin layer, the obtained molded lens 10 and the second base material 2 are bonded in the bonding device in the same manner as in Example 1. A close-contact two-layer diffractive optical element was obtained.

この回折光学素子を撮像光学系に組み込んでフレアの測定を行った。測定の結果、比較例１のフレア率は０．６２％であった。実施例１より１．５倍も高いフレア率であった。 This diffractive optical element was incorporated into an imaging optical system to measure flare. As a result of the measurement, the flare rate of Comparative Example 1 was 0.62%. The flare rate was 1.5 times higher than that of Example 1.

更に、この回折光学素子に対して高温高湿耐久試験を実施したところ、光学素子の周縁部で樹脂層間の剥がれが発生して、空気層の影響で外観上白く光る帯が観察された。これにより、耐久前と比較して回折効率、フレア率が低下していることも確認された。 Further, when a high temperature and high humidity durability test was carried out on this diffractive optical element, peeling of the resin layers occurred at the peripheral edge of the optical element, and a band shining white in appearance was observed due to the influence of the air layer. As a result, it was also confirmed that the diffraction efficiency and flare rate were lower than those before durability.

（比較例２）
比較例２は実施例１と型７の形状が異なる。輪帯数および格子角度は実施例１と同じであるが、各輪帯における型の斜面の平均表面粗さは以下のように設計した。 (Comparative Example 2)
Comparative Example 2 has a different shape from that of Example 1. The number of ring zones and the lattice angle are the same as in Example 1, but the average surface roughness of the slope of the mold in each ring zone is designed as follows.

第１輪帯〜第１８輪帯：４ｎｍ、第１９輪帯〜第３８輪帯：５ｎｍ、第３９輪帯〜第４９輪帯：６ｎｍ、第５０輪帯〜第７２輪帯：８ｎｍ、第７３輪帯〜第９８輪帯：１０ｎｍ、第９９輪帯〜第１１０輪帯：１８ｎｍ。 1st wheel band to 18th wheel band: 4 nm, 19th wheel band to 38th wheel band: 5 nm, 39th wheel band to 49th wheel band: 6 nm, 50th wheel band to 72nd wheel band: 8 nm, 73rd Ring band to 98th wheel band: 10 nm, 99th wheel band to 110th wheel band: 18 nm.

第１輪帯から第９輪帯といった素子の中心部も平均表面粗さを小さくしていることが実施例１との差異である。ここで平均表面粗さを最小値４ｎｍで調整した第１輪帯から第１８輪帯は、第１樹脂層が形成される領域の中心から周縁に向かって２０面積％の位置に相当する。 The difference from the first embodiment is that the average surface roughness of the central portion of the element such as the first wheel band to the ninth wheel band is also reduced. Here, the 1st to 18th wheel zones in which the average surface roughness is adjusted to a minimum value of 4 nm correspond to a position of 20 area% from the center of the region where the first resin layer is formed toward the peripheral edge.

得られた成形レンズ１０を光軸方向から光学顕微鏡で観察して、格子欠損の発生状況を確認したところ、素子の中心部（１〜１０輪帯近傍）で格子欠損が確認された。１つの輪帯内で周方向の１／６以上が欠損しているのは６輪帯あったが、周縁部での格子欠損は確認されなかった。 When the obtained molded lens 10 was observed with an optical microscope from the direction of the optical axis to confirm the occurrence of lattice defects, lattice defects were confirmed in the central portion of the element (near the 1st to 10th wheel bands). In one ring zone, more than 1/6 of the circumferential direction was missing in 6 ring zones, but no lattice defect was confirmed at the peripheral edge.

その後、破損後に格子成形品に再付着した格子の切れ端を除去してから、実施例１と同様の方法で、成形レンズ１０と基材２を貼り合わせ装置内で接合して密着２層型の回折光学素子を得た。 Then, after removing the pieces of the lattice reattached to the lattice molded product after the breakage, the forming lens 10 and the base material 2 are joined in the bonding device in the same manner as in the first embodiment to form a close contact two-layer type. A diffractive optical element was obtained.

この回折光学素子を撮像光学系に組み込んで、フレアの測定を行った。測定の結果、比較例２のフレア率は０．５０％であり、実施例１と比べて０．１％高かった。 This diffractive optical element was incorporated into an imaging optical system to measure flare. As a result of the measurement, the flare rate of Comparative Example 2 was 0.50%, which was 0.1% higher than that of Example 1.

この回折光学素子に対して高温高湿耐久試験を実施したが、耐久前後での光学特性に変化は認められず、光学素子の外観上も周縁部での剥がれ等の変化は認められなかった。 A high-temperature and high-humidity durability test was carried out on this diffractive optical element, but no change was observed in the optical characteristics before and after the durability, and no change such as peeling at the peripheral portion was observed in the appearance of the optical element.

この回折光学素子の直径で半分に切断した断面方向から輪帯の接合界面を観察したところ、第１樹脂層の平均表面粗さは金型の平均表面粗さを精度良く転写していることが確認された。 When observing the bonding interface of the annulus from the cross-sectional direction cut in half with the diameter of this diffractive optical element, it was found that the average surface roughness of the first resin layer accurately transferred the average surface roughness of the mold. confirmed.

（比較例３）
比較例３は、実施例１と用いた型７の形状が異なる。具体的には、型７は輪帯数および格子角度は同じであるが、切削加工機のステージの回転速度を制御することで、格子斜面の平均表面粗さを全１１０輪帯で１８ｎｍとなるように調整した。 (Comparative Example 3)
In Comparative Example 3, the shape of the mold 7 used in Example 1 is different. Specifically, the mold 7 has the same number of ring bands and the lattice angle, but by controlling the rotation speed of the stage of the cutting machine, the average surface roughness of the lattice slope becomes 18 nm for all 110 ring bands. Adjusted as.

離型も実施例１と同様に液体窒素を噴霧することでレンズを反らせる冷却離型を実施した。実施例１の時と比較すると、周縁部での剥離開始の差は無かったが、一旦剥離が開始されると中帯部、中心部まで一気に剥離が進展していくのが観察された。 As for the mold release, the cooling mold release was carried out in which the lens was warped by spraying liquid nitrogen in the same manner as in Example 1. Compared with the case of Example 1, there was no difference in the start of peeling at the peripheral portion, but once the peeling was started, it was observed that the peeling progressed to the middle zone and the central portion at once.

得られた成形レンズ１０を光軸方向から光学顕微鏡で観察して、格子欠損の発生状況を確認したところ、素子の中帯部（３０〜５０輪帯近傍）で多数の格子欠損が確認された。１つの輪帯内で周方向の１／４以上が欠損している輪帯は全１１０輪帯中２０輪帯に及んでいた。また、中帯部から周縁部では、周方向で１／４未満の格子欠損が発生していた。 When the obtained molded lens 10 was observed from the optical axis direction with an optical microscope to confirm the occurrence of lattice defects, a large number of lattice defects were confirmed in the middle zone of the element (near the 30 to 50 ring bands). .. In one ring zone, more than 1/4 in the circumferential direction was missing, covering 20 out of 110 ring zones. In addition, less than 1/4 of the lattice defects occurred in the circumferential direction from the middle zone to the peripheral edge.

その後、破損後に格子成形品に再付着した格子の切れ端を除去してから、実施例１と同様の方法で、成形レンズ１０と基材２を貼り合わせ装置内で接合して密着２層型の回折光学素子を得た。 Then, after removing the pieces of the lattice reattached to the lattice molded product after the breakage, the forming lens 10 and the base material 2 are joined in the bonding device in the same manner as in the first embodiment to form a close contact two-layer type. A diffractive optical element was obtained.

この回折光学素子を撮像光学系に組み込んで、フレアの測定を行った。測定の結果、比較例３のフレア率は０．７３％であった。実施例１より１．８倍も高いフレア率であった。 This diffractive optical element was incorporated into an imaging optical system to measure flare. As a result of the measurement, the flare rate of Comparative Example 3 was 0.73%. The flare rate was 1.8 times higher than that of Example 1.

この回折光学素子に対して高温高湿耐久試験を実施したが、耐久前後での光学特性に変化は認められず、光学素子の外観上も周縁部での剥がれ等の変化は認められなかった。 A high-temperature and high-humidity durability test was carried out on this diffractive optical element, but no change was observed in the optical characteristics before and after the durability, and no change such as peeling at the peripheral portion was observed in the appearance of the optical element.

この回折光学素子の直径で半分に切断した断面方向から輪帯の接合界面を観察したところ、第１樹脂層の平均表面粗さは金型の平均表面粗さを精度良く転写していることが確認された。 When observing the bonding interface of the annulus from the cross-sectional direction cut in half with the diameter of this diffractive optical element, it was found that the average surface roughness of the first resin layer accurately transferred the average surface roughness of the mold. confirmed.

（実施例４）
実施例４は実施例１と型７の形状が異なる。具体的には、輪帯数１１０であるが、格子角度は８７°であり、実施例１と比べて離型し易い形状となっている。また、各輪帯における型の斜面の平均表面粗さは以下のように設計した。 (Example 4)
The shape of the mold 7 of the fourth embodiment is different from that of the first embodiment. Specifically, the number of ring bands is 110, but the lattice angle is 87 °, and the shape is easier to release than that of the first embodiment. In addition, the average surface roughness of the slope of the mold in each ring zone was designed as follows.

第１輪帯〜第９輪帯：２０ｎｍ、第１０輪帯〜第１８輪帯：１０ｎｍ、第１９輪帯〜第３８輪帯：１５ｎｍ、第３９輪帯〜第４９輪帯：１８ｎｍ、第５０輪帯〜第７２輪帯：２０ｎｍ、第７３輪帯〜第９８輪帯：２５ｎｍ、第９９輪帯〜第１１０輪帯：３０ｎｍ。 1st wheel band to 9th wheel band: 20 nm, 10th wheel band to 18th wheel band: 10 nm, 19th wheel band to 38th wheel band: 15 nm, 39th wheel band to 49th wheel band: 18 nm, 50th Ring band to 72nd wheel band: 20 nm, 73rd wheel band to 98th wheel band: 25 nm, 99th wheel band to 110th wheel band: 30 nm.

実施例１と比べて、離型し易く格子欠損が抑制される形状のため、型の平均表面粗さを実施例１より大きくして、離型力を低減させた。 Since the shape is easier to release and suppresses lattice defects as compared with Example 1, the average surface roughness of the mold is made larger than that of Example 1 to reduce the mold release force.

ここで、平均表面粗さが最小値１０ｎｍとなるように調整した第１０輪帯から第１８輪帯は、第１樹脂層が形成される領域の中心から周縁に向かって１０面積％から２０面積％の位置に相当する。 Here, the 10th to 18th ring zones adjusted so that the average surface roughness is the minimum value of 10 nm have 10 area% to 20 areas from the center to the peripheral edge of the region where the first resin layer is formed. Corresponds to the% position.

離型は、第１基材１の端部を位置制御可能なイジェクタで順次押し上げる方法で行った。離型のためのイジェクタピンに設置したロードセルで離型力を測定したところ、実施例２及び３と比較して、１／４程度まで低減していることが確認された。得られた成形レンズ１０を光軸方向から光学顕微鏡で観察して、格子欠損の発生状況を確認したが、全１１０輪帯で格子欠損は確認されなかった。 The mold release was performed by a method of sequentially pushing up the end portion of the first base material 1 with a position-controllable ejector. When the mold release force was measured with a load cell installed on the ejector pin for mold release, it was confirmed that the mold release force was reduced to about 1/4 as compared with Examples 2 and 3. The obtained molded lens 10 was observed with an optical microscope from the direction of the optical axis to confirm the occurrence of lattice defects, but no lattice defects were confirmed in all 110 ring bands.

次いで、実施例１と同様の方法で、得られた成形レンズ１０と第２基材２を貼り合わせ装置内で接合して密着２層型の回折光学素子を得た。 Then, in the same manner as in Example 1, the obtained molded lens 10 and the second base material 2 were joined in a bonding device to obtain a close contact two-layer diffractive optical element.

実施例４の回折光学素子を撮像光学系に組み込んで、フレアの測定を行った。測定の結果、実施例４のフレア率は０．６５％であった。離型の際の格子欠損は抑制出来たが、格子角度が垂直に近くなっているため、フレア率は実施例１より少し高かった。 The diffractive optical element of Example 4 was incorporated into the imaging optical system, and flare was measured. As a result of the measurement, the flare rate of Example 4 was 0.65%. Although the lattice defect at the time of mold release could be suppressed, the flare rate was slightly higher than that in Example 1 because the lattice angle was close to vertical.

この回折光学素子に対して高温高湿耐久試験を実施したところ、耐久前後での光学特性に変化は認められず、光学素子の外観上も周縁部での剥がれ等の変化は認められなかった。 When a high temperature and high humidity durability test was carried out on this diffractive optical element, no change was observed in the optical characteristics before and after the durability, and no change such as peeling at the peripheral portion was observed in the appearance of the optical element.

この回折光学素子の直径で半分に切断した断面方向から輪帯の接合界面を観察したところ、第１樹脂層の平均表面粗さは金型の平均表面粗さを精度良く転写していることが確認された。 When observing the bonding interface of the annulus from the cross-sectional direction cut in half with the diameter of this diffractive optical element, it was found that the average surface roughness of the first resin layer accurately transferred the average surface roughness of the mold. confirmed.

以上、表１に実施例１から４と比較例１から３の製造条件をまとめた。また、表２に実施例１から４と比較例１から３の評価結果をまとめた。 As described above, Table 1 summarizes the production conditions of Examples 1 to 4 and Comparative Examples 1 to 3. In addition, Table 2 summarizes the evaluation results of Examples 1 to 4 and Comparative Examples 1 to 3.

実施例１では、フレアを小さくする格子角度と格子欠損レスを両立し、更に素子周縁での樹脂層間の剥離も抑えることが出来た。格子角度が大きくなり、離型が容易になった実施例２では全体的に平均表面粗さを少し大きくして離型力を低減させても、格子欠損は発生しなかった。実施例３では、硫黄を含有した樹脂に特有の課題である型との密着力が増大し離型不良が発生し易い樹脂を使用したが、金型自体の離型力を調整することで格子欠損を抑制できた。実施例４では格子角度が大きくなっているが、離型力を低減させたことで離型自体を容易にし、更に樹脂層間の剥離も生じなかった。 In Example 1, both the lattice angle for reducing flare and the absence of lattice defects were achieved, and peeling between the resin layers at the peripheral edge of the element could be suppressed. In Example 2 in which the lattice angle became large and the mold release became easy, even if the average surface roughness was slightly increased as a whole to reduce the mold release force, no lattice defect occurred. In Example 3, a resin was used, which is a problem peculiar to the sulfur-containing resin, because the adhesion to the mold is increased and mold release defects are likely to occur. However, by adjusting the mold release force of the mold itself, the lattice is used. The defect could be suppressed. Although the lattice angle was large in Example 4, the mold release itself was facilitated by reducing the mold release force, and peeling between the resin layers did not occur.

比較例１では全体が離型力の大きな状態であり、中帯部での反り不足による格子欠損が発生し、フレアが悪化してしまった。また、素子周縁部では樹脂層界面の密着力不足による剥離が確認された。比較例２では中心の離型力が大きくなっており、中心を離型する際のレンズの振れなどの影響も有って、格子欠損が素子中心に集中しており、フレアも悪化しているのが確認された。比較例３では全体の離型力が低すぎるために、十分な反りが得られず素子全域で大小の格子欠損が確認された。 In Comparative Example 1, the entire mold release force was large, lattice defects occurred due to insufficient warpage in the middle zone, and flare worsened. In addition, peeling due to insufficient adhesion at the resin layer interface was confirmed at the peripheral portion of the device. In Comparative Example 2, the mold release force at the center is large, and due to the influence of lens deflection when the center is released, lattice defects are concentrated in the center of the element, and flare is also deteriorated. Was confirmed. In Comparative Example 3, since the overall mold release force was too low, sufficient warpage could not be obtained, and large and small lattice defects were confirmed in the entire element.

１ 第１基材
１０ 成形レンズ
１１ 第２樹脂
１４ 第１輪帯
１５ 第２輪帯
１６ 第３輪帯
２ 第２基材
２０ 回折光学素子
３ 第１樹脂層
４ 第２樹脂層
５１ 斜面
５１１ 第１輪帯の斜面
５１２ 最小輪帯の斜面
５１３ 最終輪帯の斜面
５２ 壁面
６ 第１樹脂
６００ 撮像装置
６０５ レンズ
７ 型
７１ 斜面
７２ 壁面 1 1st base material 10 Molded lens 11 2nd resin 14 1st wheel band 15 2nd wheel band 16 3rd wheel band 2 2nd base material 20 Diffractive optical element 3 1st resin layer 4 2nd resin layer 51 Slope 511th Slope of 1-wheel band 512 Slope of minimum ring band 513 Slope of final ring band 52 Wall surface 6 First resin 600 Imaging device 605 Lens 7 type 71 Slope 72 Wall surface

Claims (15)

基材と、複数の斜面と複数の壁面とからなる回折格子を有する第１樹脂層と、第２樹脂層と、が順に積層され、積層方向から平面視した際に、前記回折格子が複数の同心円からなる輪帯を形成する回折光学素子において、
前記斜面の基準長さ５０μｍにおける平均表面粗さが、前記同心円の中心から最も遠い最終輪帯の斜面で最大値Ｒｍａｘであり、前記同心円の中心を囲む第１輪帯と前記最終輪帯との間の最小輪帯の斜面で最小値Ｒｍｉｎであり、前記第１輪帯の斜面の平均表面粗さが前記Ｒｍｉｎより大きく、かつ、前記Ｒｍａｘより小さいことを特徴とする回折光学素子。 A first resin layer having a base material, a diffraction grating composed of a plurality of slopes and a plurality of wall surfaces, and a second resin layer are laminated in order, and when viewed in a plan view from the stacking direction, the plurality of diffraction gratings are present. In a diffraction optical element that forms a grating of concentric circles
The average surface roughness of the slope at a reference length of 50 μm is the maximum value Rmax on the slope of the final ring zone farthest from the center of the concentric circles, and the first ring zone surrounding the center of the concentric circles and the final ring zone. A diffractive optical element having a minimum value of Rmin on the slope of the minimum ring zone between the two, and having an average surface roughness of the slope of the first ring zone larger than the Rmin and smaller than the Rmax. 前記最小輪帯と前記最終輪帯との間に位置する中間輪帯が複数あり、
前記複数の中間輪帯の斜面の基準長さ５０μｍにおける平均表面粗さが、前記最小輪帯から前記最終輪帯に向かって連続的もしくは断続的に大きくなっている請求項１に記載の回折光学素子。 There are a plurality of intermediate ring zones located between the minimum ring zone and the final ring zone.
The diffractive optics according to claim 1, wherein the average surface roughness of the slopes of the plurality of intermediate ring zones at a reference length of 50 μm increases continuously or intermittently from the minimum ring zone to the final ring zone. element. 積層方向に平面視した際に、前記最小輪帯は前記同心円の中心から最終輪帯に向かって、１０面積パーセント以上２０面積パーセント以下の範囲に位置する請求項１または２に記載の回折光学素子。 The diffractive optical element according to claim 1 or 2, wherein the minimum ring zone is located in a range of 10 area percent or more and 20 area percent or less from the center of the concentric circle toward the final ring zone when viewed in a plan view in the stacking direction. .. 前記Ｒｍａｘが１０ｎｍ以上である請求項１乃至３のいずれか１項に記載の回折光学素子。 The diffractive optical element according to any one of claims 1 to 3, wherein the Rmax is 10 nm or more. 前記Ｒｍｉｎが５ｎｍ以下である請求項１乃至４のいずれか１項に記載の回折光学素子。 The diffractive optical element according to any one of claims 1 to 4, wherein the Rmin is 5 nm or less. 前記第１輪帯の斜面の平均表面粗さが前記Ｒｍｉｎの２倍以上である請求項１乃至５のいずれか１項に記載の回折光学素子。 The diffractive optical element according to any one of claims 1 to 5, wherein the average surface roughness of the slope of the first wheel band is at least twice that of Rmin. 複数の斜面と複数の壁面から複数の同心円からなる輪帯を形成する回折格子を反転した形状を有する型と、基材との間に第１樹脂を設ける工程と、
前記第１樹脂に熱または光エネルギーを与えて前記第１樹脂を硬化させ、前記型を周縁から中心に向かって離型して第１樹脂層を得る工程と、
前記第１樹脂層の上に第２樹脂を設ける工程と、
前記第２樹脂に熱または光エネルギーを与えて前記第２樹脂を硬化させる工程と、を備える回折光学素子の製造方法であって、
前記型の斜面の基準長さ５０μｍにおける平均表面粗さが、前記同心円の中心から最も遠い最終輪帯の斜面で最大値Ｒｍａｘであり、前記同心円の中心を囲む第１輪帯と前記最終輪帯との間の最小輪帯の斜面で最小値Ｒｍｉｎであり、前記第１輪帯の斜面の平均表面粗さが前記Ｒｍｉｎより大きく、かつ、前記Ｒｍａｘより小さいことを特徴とする回折光学素子の製造方法。 A step of providing a first resin between a mold having an inverted shape of a diffraction grating forming an annular band composed of a plurality of concentric circles from a plurality of slopes and a plurality of wall surfaces, and a base material.
A step of applying heat or light energy to the first resin to cure the first resin and releasing the mold from the peripheral edge toward the center to obtain a first resin layer.
The step of providing the second resin on the first resin layer and
A method for manufacturing a diffractive optical element, comprising a step of applying heat or light energy to the second resin to cure the second resin.
The average surface roughness of the slope of the mold at a reference length of 50 μm is the maximum value Rmax on the slope of the final ring zone farthest from the center of the concentric circles, and the first ring zone and the final ring zone surrounding the center of the concentric circles. Manufacture of a diffractive optical element having a minimum value Rmin on the slope of the minimum ring zone between the two, and having an average surface roughness of the slope of the first ring zone larger than the Rmin and smaller than the Rmax. Method. 前記型は、前記最小輪帯と前記最終輪帯との間に位置する中間輪帯が複数あり、前記複数の中間輪帯の斜面の基準長さ５０μｍにおける平均表面粗さが、前記最小輪帯から前記最終輪帯に向かって連続的もしくは断続的に大きくなっている請求項７に記載の回折光学素子の製造方法。 The mold has a plurality of intermediate ring zones located between the minimum ring zone and the final ring zone, and the average surface roughness of the slopes of the plurality of intermediate ring zones at a reference length of 50 μm is the minimum ring zone. The method for manufacturing a diffractive optical element according to claim 7, wherein the diffraction optical element is continuously or intermittently increased toward the final ring zone. 前記型を平面視した際に、前記型の最小輪帯は前記同心円の中心から最終輪帯に向かって、１０面積パーセント以上２０面積パーセント以下の範囲に位置する請求項７または８に記載の回折光学素子の製造方法。 The diffraction according to claim 7 or 8, wherein when the mold is viewed in a plan view, the minimum ring zone of the mold is located in the range of 10 area% or more and 20 area% or less from the center of the concentric circle toward the final ring zone. Manufacturing method of optical element. 前記型のＲｍａｘが１０ｎｍ以上である請求項７乃至９のいずれか１項に記載の回折光学素子の製造方法。 The method for manufacturing a diffractive optical element according to any one of claims 7 to 9, wherein the Rmax of the mold is 10 nm or more. 前記型のＲｍｉｎが５ｎｍ以下である請求項１乃至１０のいずれか１項に記載の回折光学素子の製造方法。 The method for manufacturing a diffractive optical element according to any one of claims 1 to 10, wherein the Rmin of the mold is 5 nm or less. 前記型の第１輪帯の斜面の平均表面粗さが前記型のＲｍｉｎの２倍以上である請求項１乃至１１のいずれか１項に記載の回折光学素子の製造方法。 The method for manufacturing a diffractive optical element according to any one of claims 1 to 11, wherein the average surface roughness of the slope of the first wheel band of the mold is twice or more the Rmin of the mold. 筐体と、該筐体内に配置された複数のレンズを有する光学系と、を有する光学機器であって、前記レンズの少なくとも１つが請求項１乃至６のいずれか１項に記載の回折光学素子であることを特徴とする光学機器。 The diffractive optical element according to any one of claims 1 to 6, wherein the optical device has a housing and an optical system having a plurality of lenses arranged in the housing, and at least one of the lenses is An optical device characterized by being. 筐体と、該筐体内に配置された複数のレンズを有する光学系と、該光学系を通過した光を受光する撮像素子と、を有する撮像装置であって、
前記レンズの少なくとも１つが請求項１乃至６のいずれか１項に記載の回折光学素子であることを特徴とする撮像装置。 An image pickup apparatus comprising a housing, an optical system having a plurality of lenses arranged in the housing, and an image pickup element that receives light that has passed through the optical system.
An imaging device according to any one of claims 1 to 6, wherein at least one of the lenses is a diffractive optical element according to any one of claims 1 to 6. 前記撮像装置がカメラであることを特徴とする請求項１４に記載の撮像装置。 The imaging device according to claim 14, wherein the imaging device is a camera.

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