Blazed diffractive optical elements and methods of manufacturing blazed diffractive optical elements

Abstract

The present application provides a kind of blaze diffraction optical element and the manufacturing method of blaze diffraction optical element.A kind of blaze diffraction optical element, with first 1 blaze component and second 2 blaze component, and by first 1 blaze component and second 2 blaze component as grating and play a role;And intermediate layer, between first 1 blaze component and second 2 blaze component, when the refractive index of first 1 blaze component is set as Na, the refractive index of intermediate layer is set as N, the refractive index of second 2 blaze component is set as Nb, Na>N>Nb The size relationship is established.

Description

Technical Field

[0001] The present invention relates to a blazed diffraction optical element and a method for manufacturing the blazed diffraction optical element. Background Technology

[0002] Japanese Patent Application Publication No. 2011-107586 discloses a diffractive optical element comprising multiple gratings made of at least three materials stacked together. In the diffractive optical element described in Japanese Patent Application Publication No. 2011-107586, the multiple gratings have: a first assembly portion composed of mutually different materials M1A and M1B, the grating side edge of which includes two gratings arranged in contact or close proximity along the grating pitch direction; and a second assembly portion, at least one of which is made of a material different from the two gratings of the first assembly portion, and includes two gratings composed of mutually different materials M2A and M2B. Furthermore, the refractive indices N1Aw and N1Bw, Abbe numbers v1A and v1B at a certain wavelength w (nm) of the materials M1A and M1B forming the first assembly portion, and the refractive indices N2Ad and N2Bd, Abbe numbers v2A and v2B of the d-rays of the materials M2A and M2B forming the second assembly portion are appropriately set. Summary of the Invention

[0003] One embodiment of the present invention provides a blazed diffraction optical element and a method for manufacturing the blazed diffraction optical element, which can suppress ghosting caused by incident light compared to the case where the first blazed component and the second blazed component are directly stacked.

[0004] means for solving technical problems

[0005] The first aspect of the technology involved in this invention is a blazed diffraction optical element, which comprises: a blazed grating pair having a first blazed element and a second blazed element, and functioning as a grating through the first blazed element and the second blazed element; and an intermediate layer located between the first blazed element and the second blazed element, wherein when the refractive index of the first blazed element is set to Na, the refractive index of the intermediate layer is set to N, and the refractive index of the second blazed element is set to Nb, the relationship Na > N > Nb holds.

[0006] The second aspect of the technology of the present invention is the blazed diffraction optical element involved in the first aspect, wherein when the grid height of the first blazed component and the second blazed component is set to h, the thickness of the intermediate layer is set to t, and the critical angle is set to θc, the inequality h < t·tanθc and the equation θc = asin(Nb / Na) hold.

[0007] The third aspect of the technology of the present invention is a blazed diffraction optical element as described in the first or second aspect, wherein the first blazed component has a first serrated surface, the second blazed component has a second serrated surface, and the first and second serrated surfaces are complementaryly engaged via an intermediate layer.

[0008] The fourth aspect of the technology of the present invention is a blazed diffraction optical element as described in the first or second aspect, wherein the first blazed component has a first serrated surface, the second blazed component has a second serrated surface, the first serrated surface is formed by a first steep slope and a first gentle slope with a gradient gentler than the first steep slope, the second serrated surface is formed by a second steep slope and a second gentle slope with a gradient gentler than the second steep slope, and an intermediate layer is disposed between the first serrated surface and the second serrated surface.

[0009] The fifth aspect of the present invention is the blazed diffraction optical element of the third aspect, wherein the first serrated surface is formed by a first steep slope and a first gentle slope with a gradient gentler than the first steep slope, the second serrated surface is formed by a second steep slope and a second gentle slope with a gradient gentler than the second steep slope, and the intermediate layer is disposed between the first serrated surface and the second serrated surface.

[0010] The sixth aspect of the present invention relates to a blazed diffraction optical element as described in the first aspect, wherein a first blazed component has a first serrated surface, a second blazed component has a second serrated surface, the first serrated surface is formed by a first steep slope and a first gentle slope with a gradient gentler than the first steep slope, the second serrated surface is formed by a second steep slope and a second gentle slope with a gradient gentler than the second steep slope, and when the thickness of the intermediate layer between the first and second steep slopes is set to t, the grid height of the first and second blazed components is set to h, and the critical angle is set to θc, the inequality h < t·tanθc and the equation θc = asin(Nb / Na) hold.

[0011] The seventh aspect of the technology of the present invention is a blazed diffraction optical element involved in any one of the fourth to sixth aspects, wherein the first blazed component has a first reference plane, the second blazed component has a second reference plane, the first steep slope surface and the first gentle slope surface are surfaces that stand upright from the first reference plane, the second steep slope surface and the second gentle slope surface are surfaces that stand upright from the second reference plane, the first steep slope surface is perpendicular to the first reference plane, and the second steep slope surface is perpendicular to the second reference plane.

[0012] The eighth aspect of the technology of the present invention is a blazed diffraction optical element involved in any one of the third to seventh aspects, wherein the first serrated surface and the second serrated surface are engaged by offsetting the thickness of the intermediate layer.

[0013] The ninth aspect related to the technology of the present invention is the blazed diffractive optical element related to any one of the first to eighth aspects, wherein the intermediate layer is composed of multiple layers having a refractive index that decreases from the first blazed component side to the second blazed component side.

[0014] The tenth aspect related to the technology of the present invention is the blazed diffractive optical element related to any one of the first to ninth aspects, wherein the intermediate layer is formed in a film shape.

[0015] The eleventh aspect related to the technology of the present invention is the blazed diffractive optical element related to any one of the first to tenth aspects, wherein the blaze angle of the first blazed component and the blaze angle of the second blazed component are the same.

[0016] The twelfth aspect related to the technology of the present invention is the blazed diffractive optical element related to any one of the first to eleventh aspects, wherein the grating height of the first blazed component is the same as the grating height of the second blazed component. <{

[0017] The thirteenth aspect related to the technology of the present invention is a blazed diffractive optical element, which includes: a blazed component and a layer provided on the blazed component, and the refractive index of the layer is between the refractive index of the blazed component and the refractive index of the environment surrounding the blazed component.

[0018] The fourteenth aspect related to the technology of the present invention is the blazed diffractive optical element related to the thirteenth aspect, wherein the surrounding environment is the aqueous humor in the eye, and the refractive index of the layer is between the refractive index of the blazed component and the refractive index of the aqueous humor.

[0019] The fifteenth aspect related to the technology of the present invention is the blazed diffractive optical element related to the fourteenth aspect, wherein when the refractive index of the aqueous humor is set as A, the refractive index of the surface layer is set as B, and the refractive index of the blazed component is set as C, the magnitude relationship of A < B < C holds.

[0020] The sixteenth aspect related to the technology of the present invention is the blazed diffractive optical element related to the fifteenth aspect, wherein when the grating height of the blazed component is set as h, the thickness of the layer is set as t, and the critical angle is set as θc, the inequality h < t·tanθc and the equation θc = asin(A / C) hold.

[0021] The seventeenth aspect related to the technology of the present invention is the blazed diffractive optical element related to the fifteenth or sixteenth aspect, wherein the blazed component has a serrated surface, and the layer is formed in a shape corresponding to the serrated surface on the serrated surface.

[0022] The 18th mode related to the technology of the present invention is the blazed diffractive optical element related to the 17th mode, wherein the serrated surface is formed by a steep slope surface and a gentle slope surface with a gentler gradient than the steep slope surface.

[0023] The 19th mode related to the technology of the present invention is the blazed diffractive optical element related to the 18th mode, wherein the blazed component has a reference surface, the steep slope surface and the gentle slope surface are surfaces erected from the reference surface, and the steep slope surface is perpendicular to the reference surface. <​​​​​​​​​​​​​​​​​​The 26th aspect of the present invention relates to a method for manufacturing a blazed diffractive optical element according to any one of the 23rd to 25th aspects, wherein a first blazed component has a first serrated surface, a second blazed component has a second serrated surface, and in the process of forming the second blazed component, the first serrated surface and the second serrated surface are engaged by offsetting the thickness of the intermediate layer. Attached Figure Description

[0031] Figure 1 This is a schematic cross-sectional view showing an example of the cross-sectional structure of a coupled optical element.

[0032] Figure 2 This is a schematic perspective view showing an example of the appearance of a plano-convex lens used in a coupled optical element.

[0033] Figure 3 This is a schematic perspective view showing an example of the appearance of a biconcave lens used in a coupled optical element.

[0034] Figure 4 This is a conceptual diagram illustrating an example of the appearance of the first and second serrated surfaces.

[0035] Figure 5 This is a flowchart illustrating an example of a manufacturing method for a stacked blazed diffraction optical element.

[0036] Figure 6 This is a schematic perspective view showing an example of how ultraviolet-cured resin is flowed into the mold cavity during the first shimmering component forming process.

[0037] Figure 7 This is a schematic perspective view showing an example of how, in the first shimmering component forming process, the convex surface of a plano-convex lens is placed into a cavity containing ultraviolet-cured resin.

[0038] Figure 8 This is a schematic perspective view showing an example of how ultraviolet light is irradiated from the planar side of a plano-convex lens during the first shimmering component forming process.

[0039] Figure 9 This is a schematic perspective view illustrating an example of spin coating in the intermediate layer formation process.

[0040] Figure 10 This is a schematic perspective view illustrating an example of how ultraviolet-cured resin coated on the entire surface of the first shimmering component is irradiated with ultraviolet light during the intermediate layer formation process.

[0041] Figure 11 This is a schematic perspective view showing an example of how ultraviolet-cured resin is flowed into a concave surface of a biconcave lens during the second shimmering component forming process.

[0042] Figure 12 This is a schematic perspective view showing an example of a plano-convex lens, on which an intermediate layer is formed on the first blazing component, in the second blazing component forming process, in a concave surface containing ultraviolet-cured resin, allowing the lens to enter from the intermediate layer side.

[0043] Figure 13 This is a conceptual diagram illustrating an example of how ultraviolet light is irradiated from the other concave side of a biconcave lens during the second shimmering component forming process.

[0044] Figure 14 This is a conceptual diagram illustrating an example of the structure of a conventional stacked blazed diffraction optical element.

[0045] Figure 15 This is a conceptual diagram illustrating an example of the structure of a conventional stacked blazed diffraction optical element.

[0046] Figure 16 This is a schematic partial cross-sectional view showing an example of the structure of a stacked blazed diffraction optical element.

[0047] Figure 17 This is a schematic partial cross-sectional view illustrating an example of how subject light is incident on a cascaded blazed diffraction optical element, or sometimes within a cascaded blazed diffraction optical element.

[0048] Figure 18 This is a schematic partial cross-sectional view showing the structure of a first modified example of a stacked blazed diffraction optical element.

[0049] Figure 19 This is a schematic partial cross-sectional view of a second modified example of the structure of a stacked blazed diffraction optical element.

[0050] Figure 20 This is a schematic cross-sectional view showing an example of the structure of a blazed diffraction optical element. Detailed Implementation

[0051] Hereinafter, an example of an embodiment of the stacked blazed diffraction optical element and the method for manufacturing the stacked blazed diffraction optical element according to the present invention will be described with reference to the accompanying drawings.

[0052] Furthermore, in this specification, "perpendicular" means, besides being perfectly perpendicular, an error that includes the degree of error generally permissible in the technical field to which this invention pertains, and does not contradict the spirit of this invention. Similarly, "orthogonal" means, besides being perfectly orthogonal, an error that includes the degree of error generally permissible in the technical field to which this invention pertains, and does not contradict the spirit of this invention. Likewise, "parallel" means, besides being perfectly parallel, an error that includes the degree of error generally permissible in the technical field to which this invention pertains, and does not contradict the spirit of this invention. Finally, "identical" means, besides being completely identical, an error that includes the degree of error generally permissible in the technical field to which this invention pertains, and does not contradict the spirit of this invention.

[0053] <Overall structure of the bonding optical elements>

[0054] As an example, such as Figure 1 As shown, the bonding optical element 10 includes a pair of lenses and a stacked blazed diffraction optical element 12. The bonding optical element 10 is used, for example, as a lens for optical devices (e.g., digital cameras, projectors, and microscopes) and a lens for vision correction devices (e.g., eyeglasses and contact lenses).

[0055] The pair of lenses included in the bonding optical element 10 are glass lenses and transmit ultraviolet (UV) light (see reference). Figure 8 , Figure 10 and Figure 13 ).exist Figure 1 In the example shown, as a pair of lenses, plano-convex lens 14 is shown (see also [reference]). Figure 2 ) and biconcave lens 16 (see also reference) Figure 3 Here, a combination of a plano-convex lens 14 and a biconcave lens 16 is shown as a pair of lenses, but this is only one example. The pair of lenses can be a combination of other types of lenses (e.g., a combination of a biconcave lens and a plano-concave lens). Furthermore, the pair of lenses does not need to be made of glass; it can be made of resin.

[0056] In addition, for ease of explanation, the thickness direction of the plano-convex lens 14 and the biconcave lens 16 will be defined as the Z direction, the width direction of the plano-convex lens 14 and the biconcave lens 16 will be defined as the X direction, and the depth direction of the plano-convex lens 14 and the biconcave lens 16 in the figure, that is, the direction orthogonal to the Z direction and the X direction, will be defined as the Y direction.

[0057] The stacked blazed diffraction optical element 12 is an example of a "blazed diffraction optical element" according to the technology of the present invention, and includes a blazed grating pair 18. The blazed grating pair 18 has a first blazed element 20 and a second blazed element 22, and functions as a grating by means of the first blazed element 20 and the second blazed element 22.

[0058] As an example, such as Figure 1 As shown, the first blazing member 20 has a surface and a back surface in the Z direction, the back surface being adjacent to the convex surface 14A of the plano-convex lens 14 (see also reference). Figure 2 ) Joining. The surface of the first shimmering component 20 is a first serrated surface 20A. The first serrated surface 20A is formed so that it appears serrated in cross-sectional view. As an example, such as Figure 4 As shown, when the first shimmering component 20 is viewed from below in the Z direction, a wedge-shaped groove 26 is formed in a concentric circle on the first serrated surface 20A.

[0059] As an example, such as Figure 1 As shown, the second blazing component 22 has a surface and a back surface in the Z direction, the back surface being adjacent to a concave surface 16A of the biconcave lens 16 (see also reference). Figure 3 The second shimmering component 22 has a second serrated surface 22A. The second serrated surface 22A is formed so that it appears serrated in cross-sectional view. As an example, such as Figure 4 As shown, when the second shimmering component 22 is viewed from the upper part in the Z direction, a wedge-shaped groove 28 is formed in a concentric circle on the second serrated surface 22A.

[0060] As an example, such as Figure 1 As shown, the stacked blazed diffraction optical element 12 includes an intermediate layer 24. The intermediate layer 24 is located between the first blazed element 20 and the second blazed element 22.

[0061] Here, when the refractive index of the first blazing element 20 is set to Na, the refractive index of the intermediate layer 24 is set to N, and the refractive index of the second blazing element 22 is set to Nb, the relationship "Na > N > Nb" holds true. Figure 1 In the examples shown, "1.58" is shown as an example of refractive index Na, "1.57" is shown as an example of refractive index N, and "1.56" is shown as an example of refractive index Nb.

[0062] <Manufacturing Method of Stacked Blazed Diffraction Optical Elements>

[0063] Figure 5 An example of a method for manufacturing a stacked blazed diffraction optical element 12 is shown. Figure 5 The manufacturing method shown includes: a first shimmering component forming process in step ST100, an intermediate layer forming process in step ST102, and a second shimmering component forming process in step ST104.

[0064] In step ST100, a first blazing member 20 is formed. In step ST102, an intermediate layer 24 is formed on the first serrated surface 20A of the first blazing member 20. The first serrated surface 20A is an example of a "blazing portion" according to the technology of this invention. In step ST104, a second blazing member 22, paired with the first blazing member 20, is formed on the side of the intermediate layer 24 opposite to the side of the first blazing member 20. Hereinafter, the steps for forming the first blazing member, the intermediate layer, and the second blazing member will be described in detail.

[0065] <First Shining Component Forming Process>

[0066] When crafting the first Shining Part 20, as an example, such as Figure 6 As shown, cavity 34 is used. Cavity 34 is a mold for forming the first serrated surface 20A. A recess 36 is formed in the center of cavity 34. The recess 36 is formed in a bowl shape. The surface of the recess 36 is a concentric circular surface 36A. The concentric circular surface 36A has a wedge-shaped groove (e.g., with the center of the bottom of the recess 36) formed concentrically in a circular pattern. Figure 4 The surface of the wedge-shaped groove (corresponding to the groove shown). The size and shape of the concentric circular surface 36A correspond to the second serrated surface 22A. That is, the concentric circular surface 36A and the second serrated surface 22A are formed with the same size and shape.

[0067] The first shimmering component 20 is allowed to flow into the recess 36 with liquid UV-cured resin 38 to prevent air bubbles from entering the recess 36. Furthermore, regarding the size and shape of the concentric circular surface 36A, it is considered that in a later process, UV light will be irradiated relative to the UV-cured resin 38 within the recess 36 (see reference). Figure 8 The design was based on the shrinkage rate of the UV-cured resin 38 during the curing process.

[0068] When the UV-cured resin 38 flows into the pit 36, then, as an example, such as Figure 7 As shown, the plano-convex lens 14 is inserted into the recess 36 such that the convex surface 14A covers the recess 36. That is, with the convex surface 14A facing the concentric circular surface 36A, the plano-convex lens 14 is sank from the convex surface 14A into the ultraviolet-cured resin 38 in the recess 36. The ultraviolet-cured resin 38 overflowing from the recess 36 is wiped away.

[0069] Next, as an example, such as Figure 8As shown, with the plano-convex lens 14 inserted into the recess 36, the ultraviolet irradiation device 40 irradiates ultraviolet (UV) light from the plane 14B (the side opposite to the convex surface 14A) of the plano-convex lens 14. The UV light passes through the plano-convex lens 14 and irradiates the UV-curing resin 38 within the recess 36. As a result, the UV-curing resin 38 cures, forming the first blazing element 20 on the convex surface 14A (see reference). Figure 1 , Figure 4 and Figure 9 ).

[0070] <Intermediate Layer Formation Process>

[0071] When fabricating the intermediate layer 24, the plano-convex lens 14 is first removed from the cavity 34. Furthermore, as an example, such as... Figure 9 As shown, the plano-convex lens 14 is positioned on the upper surface 42A1 of the rotary table 42A of the spin coater 42 with the first serrated surface 20A facing upwards. The plane 14B of the plano-convex lens 14 (reference) Figure 8 The center of the plano-convex lens 14 is aligned with the center of the upper surface 42A1.

[0072] As for the mounting method of the plano-convex lens 14 relative to the upper surface 42A1, examples include mounting methods based on adsorption and / or mounting methods based on pressing components.

[0073] Next, with the plano-convex lens 14 mounted on the upper surface 42A1 of the disk stage 42A, the intermediate layer 24 is poured onto the center of the first serrated surface 20A using liquid ultraviolet-curable resin 44. The ultraviolet-curable resin 44 is preferably an acrylic or epoxy ultraviolet-curable resin. Furthermore, a thermosetting resin can be used instead of an ultraviolet-curable resin. The refractive index of the intermediate layer 24 can also be adjusted by changing the substituent R of the methacrylic acid polymer. Furthermore, the refractive index of the intermediate layer 24 can be adjusted by adjusting the mixing ratio of various materials.

[0074] Next, while the UV-curable resin 44 is falling toward the center of the first serrated surface 20A, the disc stage 42A is rotated at high speed. The rotation of the disc stage 42A applies centrifugal force to the UV-curable resin 44, and the UV-curable resin 44 diffuses and coats the entire first serrated surface 20A.

[0075] Next, as an example, such as Figure 10As shown, the ultraviolet irradiation device 40 irradiates the entire ultraviolet-curable resin 44 diffusely coated on the first serrated surface 20A with ultraviolet UV light. As a result, the ultraviolet-curable resin 44 cures on the first serrated surface 20A, and the intermediate layer 24 is formed into a film on the first serrated surface 20A. Furthermore, since the intermediate layer 24 is a single layer, one film-forming process is sufficient; however, when the intermediate layer 24 is multilayered, the same film-forming process is repeated only a certain number of times.

[0076] <Second Shining Component Forming Process>

[0077] When creating the second Shining Part 22, as an example, such as Figure 11 As shown, the second blazing component 22 is made to flow into the concave surface 16A of the biconcave lens 16 using liquid ultraviolet-cured resin 48 to prevent air bubbles from entering.

[0078] Next, as an example, such as Figure 12 As shown, the plano-convex lens 14 is inserted into the concave surface 16A side of the biconcave lens 16 such that the intermediate layer 24 covers the concave surface 16A. That is, with the intermediate layer 24 facing the concave surface 16A, the plano-convex lens 14 is submerged from the intermediate layer 24 into the UV-curable resin 48 on the concave surface 16A side of the biconcave lens 16. UV-curable resin 48 overflowing from the concave surface 16A is wiped away.

[0079] Next, as an example, such as Figure 13 As shown, with the plano-convex lens 14 positioned on the concave side 16A of the biconcave lens 16, the ultraviolet irradiation device 50 irradiates ultraviolet (UV) light from the other concave side 16B (the side opposite to concave side 16A) of the biconcave lens 16. The UV light passes through the biconcave lens 16 and irradiates the UV-curable resin 48. Consequently, the UV-curable resin 48 cures, forming the second blazing member 22 on the concave side 16A.

[0080] <Previous stacked blazed diffraction optical elements>

[0081] exist Figure 14 and Figure 15 As an example of a conventional diffractive optical element, a stacked blazed diffractive optical element without an intermediate layer is shown, namely a stacked blazed diffractive optical element 100 in which a pair of blazed components are directly engaged.

[0082] As an example, such as Figure 14 As shown, in the stacked blazed diffraction optical element 100, a pair of blazed elements are formed by a first blazed element 102 corresponding to the first blazed element 20 and a second blazed element 104 corresponding to the second blazed element 22.

[0083] The first shimmering component 102 has a first serrated surface 106 corresponding to the first serrated surface 20A. The first shimmering component 102 has a first reference surface 102A. The first reference surface 102A is a virtually defined surface, for example, relative to the convex surface 14A (reference). Figure 1 (A plane parallel to another plane.)

[0084] The first serrated surface 106 is formed by a first steep slope surface 106A and a first gentle slope surface 106B. The first gentle slope surface 106B is a surface with a gentler gradient relative to the first reference surface 102A than the first steep slope surface 106A. The first steep slope surface 106A is a surface perpendicular to the first reference surface 102A, and the height of the first steep slope surface 106A from the first reference surface 102A is the grid height of the first blazing member 102. Alternatively, the first steep slope surface 106A may not be perpendicular to the first reference surface 102A. This is because, in the optical system used, the angle of the first steep slope surface 106A is appropriately determined to maximize the diffraction efficiency relative to the direction of the main incident light.

[0085] The second shimmering component 104 has a second serrated surface 108 corresponding to the second serrated surface 22A. The second shimmering component 104 has a second reference surface 104A. The second reference surface 104A is a virtually defined surface, for example, relative to the concave surface 16A (reference). Figure 1 (A plane parallel to another plane.)

[0086] The second serrated surface 22A is formed by the second steep slope surface 108A and the second gentle slope surface 108B. The second gentle slope surface 108B is a surface with a gentler gradient than the second steep slope surface 108A relative to the second reference surface 104A. The second steep slope surface 108A is a surface perpendicular to the second reference surface 104A, and the height of the second steep slope surface 108A from the second reference surface 104A is the grid height of the second shimmering component 104.

[0087] The first serrated surface 106 of the first blazing member 102 directly engages with the second serrated surface 108 of the second blazing member 104. In this case, the first steep slope surface 106A is in direct contact with the second steep slope surface 108A, and the first gentle slope surface 106B is in direct contact with the second gentle slope surface 108B. Additionally, in... Figure 14 and Figure 15 In the diagram, for ease of explanation, when there is no need to distinguish between the first steep slope 106A and the second steep slope 10gA, they are referred to as "steep slopes" without being assigned a symbol, and when there is no need to distinguish between the first gentle slope 106B and the second gentle slope 108B, they are referred to as "gentle slopes" without being assigned a symbol.

[0088] The refractive index of the first blazing component 102 is higher than that of the second blazing component 104. Figure 14In the example shown, the refractive index of the first blazing element 102 is shown as "1.58", and the refractive index of the second blazing element 104 is shown as "1.56".

[0089] In this case, the subject light enters from the first blaze element 102 (a layer with a refractive index of "1.58") via a gentle slope to the second blaze element 104 (a layer with a refractive index of "1.56"), then enters the first blaze element 102 again via a steep slope, and finally enters the second blaze element 104 via a gentle slope. Here, the subject light is refracted at the steep slope according to the angle θ1 at which it enters. Figure 14 In the example shown, the angle θ1 at which the subject light is incident on the steep slope is 5 degrees, and the angle θ2 at which the subject light is refracted on the steep slope is 7 degrees. As a result, ghosting is mapped in the photographic image obtained by using an image sensor, based on the refraction of the subject light.

[0090] exist Figure 14 In the example shown, the subject light transmitted from the first flare element 102 through the gentle slope is incident on the steep slope, but Figure 15 In the example shown, the subject light incident on the first blazing element 102 directly illuminates the steep slope without passing through a gentle slope. In this case, the subject light undergoes total internal reflection on the steep slope, depending on the angle θ1. For example, when the angle θ1 is in the range of 0 degrees to 11 degrees, the subject light is totally internally reflected on the steep slope. As a result, ghosting caused by the total internal reflection of the subject light is mapped in the photographic image obtained by capturing it using an image sensor.

[0091] <Details on stacked blazed diffraction optical elements>

[0092] Given this situation, as an example, such as Figure 18 As shown, the stacked blazed diffraction optical element 12 includes a blazed grating pair 18 and an intermediate layer 24. The intermediate layer 24 with refractive index N is located between the first blazed element 20 with refractive index Na and the second blazed element 22 with refractive index Nb. Furthermore, the order "Na > N > Nb" holds true between the first blazed element 20 with refractive index Na, the second blazed element 22 with refractive index Nb, and the intermediate layer 24 with refractive index N.

[0093] Furthermore, the first serrated surface 20A is formed by a first steep slope surface 20A1 and a first gentle slope surface 20A2 with a gentler gradient than the first steep slope surface 20A1. The second serrated surface 22A is formed by a second steep slope surface 22A1 and a second gentle slope surface 22A2 with a gentler gradient than the second steep slope surface 22A1. Moreover, the intermediate layer 24 is disposed between the first steep slope surface 20A1 and the second steep slope surface 22A1, between the first serrated surface 20A and the second serrated surface 22A.

[0094] Furthermore, the first serrated surface 20A and the second serrated surface 22A are complementaryly engaged via the intermediate layer 24. That is, the first serrated surface 20A and the second serrated surface 22A are engaged via the intermediate layer 24 in a manner in which the first steep slope surface 20A1 and the second steep slope surface 22A1 are alternately arranged in the X direction.

[0095] Furthermore, the first shimmering component 20 has a first reference surface 52, and the second shimmering component 22 has a second reference surface 54. The first reference surface 52 and the second reference surface 54 are virtually defined surfaces. The first reference surface 52 is adjacent to the convex surface 14A (reference). Figure 1 The second reference plane 54 is parallel to the concave plane 16A (reference). Figure 1 Parallel planes.

[0096] The first steep slope surface 20A1 and the first gentle slope surface 20A2 are surfaces that rise from the first reference surface 52, and the second steep slope surface 22A1 and the second gentle slope surface 22A2 are surfaces that rise from the second reference surface 54. The first steep slope surface 20A1 is perpendicular to the first reference surface 52, and the second steep slope surface 22A1 is perpendicular to the second reference surface 54.

[0097] Furthermore, the first serrated surface 20A and the second serrated surface 22A are engaged by offsetting the thickness of the intermediate layer 24. That is, the first serrated surface 20A and the second serrated surface 22A are engaged via the intermediate layer 24.

[0098] Furthermore, the flare angle of the first flare component 20 and the flare angle of the second flare component 22 are the same. Also, the grille height of the first flare component 20 is the same as the grille height of the second flare component.

[0099] As an example, such as Figure 17 As shown, in the stacked blazed diffraction optical element 12, in order to allow the subject light to pass from the first blazed element 20 through the intermediate layer 24 to the second blazed element 22, the grating height h and the thickness t of the intermediate layer 24 are determined in such a way that when the grating height of the first blazed element 20 and the second blazed element 22 is set to h, the thickness of the intermediate layer 24 is set to t, and the critical angle is set to θc, the inequality h < t·tanθ and the equation θc = asin(Nb / Na) hold.

[0100] In addition, the thickness t of the intermediate layer 24 represents the thickness between the first gentle slope 20A2 and the second gentle slope 22A2, and the thickness between the first steep slope 20A1 and the second steep slope 22A1.

[0101] Furthermore, here, the critical angle refers to the minimum angle of incidence at which subject light cannot pass through the second blaze element 22 when it is irradiated from the side of the first blaze element 20 of the stacked blaze diffraction optical element 12. Here, "unable to transmit subject light" means, for example, that total internal reflection of the subject light between layers (mediums) with different refractive indices results in the subject light not passing through the interlayer. The angle of incidence refers to the angle of the light path of the subject light incident relative to the interface between adjacent layers (e.g., the interface between the first blaze element 20 and the intermediate layer 24, and the interface between the intermediate layer 24 and the second blaze element 22). Figure 17 In the example shown, the angle of the light path of the subject light incident relative to the interface of the adjacent layers is the angle relative to the normal of the interface.

[0102] <Function and Effects of Stacked Blazed Diffraction Optical Elements>

[0103] Next, the function of the stacked blazed diffraction optical element 12 will be explained.

[0104] Between a first medium and a second medium, where the refractive index of the first medium is less than the refractive index of the second medium, when the subject light shines from the second medium side toward the first medium side, the subject light undergoes total internal reflection at an angle greater than or equal to the critical angle θc = asin{(refractive index of the first medium) / (refractive index of the second medium)}.

[0105] exist Figure 17 In the example shown, the critical angle θc between the first blazing element 20 and the intermediate layer 24 is greater than the critical angle θc between the first blazing element 20 and the second blazing element 22. Therefore, even if the angle of the subject light incident from the first blazing element 20 relative to the intermediate layer 24 is greater than the critical angle θc between the first blazing element 20 and the second blazing element 22, the subject light incident from the first blazing element 20 relative to the intermediate layer 24 will not be refracted by total internal reflection in the intermediate layer 24. The refracted subject light reaches the intermediate layer 24 before reaching the second blazing element 22. Figure 17 The lower surface 56 (the interface (boundary surface) between the intermediate layer 24 and the second blazing component 22) is incident on the second blazing component 22 adjacent to the lower surface 56.

[0106] This is because the grid height h and the thickness t of the intermediate layer 24 are determined by the inequality h < t·tanθ and the equation θc = asin(Nb / Na), so the subject light reaches the lower surface 56 of the intermediate layer 24 in the figure before total internal reflection.

[0107] Here, in Figure 17In the example shown, the critical angle θc1 between the first diffraction element 20 and the intermediate layer 24 is 83.6 degrees. Therefore, even for subject light having an incident angle exceeding 79 degrees, which is the critical angle θc when the intermediate layer 24 is not present, when the incident angle is less than 83.6 degrees, total reflection does not occur between the first diffraction element 20 and the intermediate layer 24. That is, when the subject light incident on the joint surface between the first diffraction element 20 and the intermediate layer 24 is within the range of 79 degrees < angle θ < 83.6 degrees, total reflection does not occur at the joint surface between the first diffraction element 20 and the intermediate layer 24, and the light enters the intermediate layer 24. Further, the subject light that has entered the intermediate layer 24 enters the second diffraction element 22 from the lower surface 56 in the drawing of the intermediate layer 24.

[0108] As described above, the stacked diffraction grating optical element 12 includes: a diffraction grating pair 18 that functions as a grating by the first diffraction element 20 and the second diffraction element 22; and an intermediate layer 24 disposed between the first diffraction element 20 and the second diffraction element 22. Moreover, a size relationship of "Na > N > Nb" holds among the first diffraction element 20 having a refractive index Na, the second diffraction element 22 having a refractive index Nb, and the intermediate layer 24 having a refractive index N. Therefore, according to this structure, compared with the case where the first diffraction element 20 and the second diffraction element 22 are directly stacked, it is possible to suppress ghosting caused by total reflection of the incident light. Further, according to this structure, due to the presence of the intermediate layer 24, the distance required for the light to be completely refracted becomes longer, and thus the light reaches the lower surface 56 (see Figure 17 ), and therefore, it is also possible to suppress ghosting caused by refraction of the incident light.

[0109] Further, in the stacked diffraction grating optical element 12, when the grating height of the first diffraction element 20 and the second diffraction element 22 is h, the thickness of the intermediate layer 24 is t, and the critical angle is θc, the inequality h < t·tanθ and the equation θc = asin(Nb / Na) hold. Therefore, according to this structure, compared with the case where the grating height and the thickness of the intermediate layer 24 are determined under conditions where the inequality h < t·tanθc and the equation θc = asin(Nb / Na) do not hold, it is possible to easily determine the optimal grating height and the optimal thickness of the intermediate layer 24 as the grating height and the thickness of the intermediate layer 24 that are less likely to cause ghosting.

[0110] Further, in the stacked diffraction grating optical element 12, the first serrated surface 20A and the second serrated surface 22A are complementarily engaged via the intermediate layer 24. Therefore, according to this structure, compared with the case where the first serrated surface 20A and the second serrated surface 22A are not complementarily engaged via the intermediate layer 24, it is possible to suppress ghosting caused by the incident light.

[0111] Also, in the stacked blazed diffractive optical element 12, the intermediate layer 24 is disposed between the first steep slope surface 20A1 and the second steep slope surface 22A1 between the first serrated surface 20A and the second serrated surface 22A. Therefore, according to this structure, compared with the case where the intermediate layer 24 is not disposed between the first steep slope surface 20A1 and the second steep slope surface 22A, it is possible to suppress ghosting caused by light incident on the first steep slope surface 20A1 and the second steep slope surface 22A.

[0112] Also, in the stacked blazed diffractive optical element 12, between the first serrated surface 20A and the second serrated surface 22A, between the first steep slope surface 20A1 and the second steep slope surface 22A, when the thickness of the intermediate layer 24 is set to t, the grating height of the first blazed member 20 and the second blazed member 22 is set to h, and the critical angle is set to θc, the inequality h < t·tanθ and the equation θc = asin(Nb / Na) hold. Therefore, according to this structure, compared with the case where the grating height and the thickness of the intermediate layer 24 between the first steep slope surface 20A1 and the second steep slope surface 22A are determined using conditions where the inequality h < t·tanθc and the equation θc = asin(Nb / Na) do not hold, it is possible to easily determine the optimal grating height and the optimal thickness of the intermediate layer 24 as the grating height that is not prone to ghosting and the thickness of the intermediate layer 24 between the first steep slope surface 20A1 and the second steep slope surface 22A that is not prone to ghosting.

[0113] Also, in the stacked blazed diffractive optical element 12, the first steep slope surface 20A1 is perpendicular to the first reference surface 52, and the second steep slope surface 22A1 is perpendicular to the second reference surface 54. Therefore, according to this structure, compared with the case where the first steep slope surface 20A1 is not perpendicular to the first reference surface 52 and the second steep slope surface 22A1 is not perpendicular to the second reference surface 54, it is possible to suppress ghosting caused by light incident on the first steep slope surface 20A1 and the second steep slope surface 22A.

[0114] Also, in the stacked blazed diffractive optical element 12, the first serrated surface 20A and the second serrated surface 22A are engaged with each other with a displacement corresponding to the thickness of the intermediate layer 24. Therefore, according to this structure, compared with the case where the first serrated surface 20A and the second serrated surface 22A are not engaged with each other with a displacement corresponding to the thickness of the intermediate layer 24, it is possible to suppress ghosting caused by the incident light.

[0115] Also, in the stacked blazed diffractive optical element 12, the intermediate layer 24 is formed in a film shape. Therefore, according to this structure, it is possible to contribute to the thinning of the stacked blazed diffractive optical element 12.

[0116] Furthermore, in the stacked blaze diffraction optical element 12, the blaze angles of the first blaze member 20 and the second blaze member 22 are the same. Therefore, according to this structure, compared with the case where the blaze angles of the first blaze member 20 and the second blaze member 22 are inconsistent, ghosting caused by incident light can be suppressed.

[0117] Furthermore, in the stacked blazed diffraction optical element 12, the grating height of the first blazed element 20 is the same as that of the second blazed element. Therefore, according to this structure, compared with the case where the grating height of the first blazed element 20 and the grating height of the second blazed element are inconsistent, ghosting caused by incident light can be suppressed.

[0118] Furthermore, the intermediate layer formation process included in the manufacturing method of the stacked blazed diffraction optical element 12 includes a process of forming the intermediate layer 24 by spin coating. Therefore, according to this structure, compared with the case of vapor-deposited intermediate layer 24, it is easier to form the intermediate layer 24 into a film with uniform thickness.

[0119] Furthermore, in the above embodiment, an example was described in which the intermediate layer 24 is situated between the entire surface of the first gentle slope surface 20A2 and the entire surface of the second gentle slope surface 22A2; however, the technology of the present invention is not limited thereto. For example, as... Figure 18 As shown, the intermediate layer 24 can be positioned between at least the first steep slope 20A1 in the first serrated surface 20A and at least the second steep slope 22A1 in the second serrated surface 22A. Therefore, compared to the case where no intermediate layer 24 is disposed between the first steep slope 20A1 and the second steep slope 22A1, ghosting caused by light incident on the first steep slope 20A1 and the second steep slope 22A1 can be suppressed.

[0120] Furthermore, while the above embodiments illustrate an example where the intermediate layer 24 is a single layer, the technology of the present invention is not limited thereto, and the intermediate layer 24 can be a multi-layered structure. Figure 19 In the example shown, the intermediate layer 24 is formed by a first layer 30 and a second layer 32. The first layer 30 and the second layer 32 are stacked. The first layer 30 is bonded to the first serrated surface 20A, and the second layer 32 is bonded to the second serrated surface 22A. That is, from the convex surface 14A (reference) Figure 1 ) to concave surface 16A (reference) Figure 1 The first shining component 20, the first layer 30, the second layer 32 and the second shining component 22 are stacked in sequence.

[0121] Here, when the refractive index of the first layer 30 is set to N1 and the refractive index of the second layer 32 is set to N2, the order "Na > N1 > N2 > Nb" holds true among the refractive indices Na of the first blazed element 20, N1 of the first layer 30, N2 of the second layer 32, and Nb of the second blazed element. Thus, in the intermediate layer 24, if the refractive index is precisely changed, the total internal reflection angle at each interface increases, thereby widening the range of angles from which total internal reflection does not occur, which is preferable. Therefore, according to this structure, compared to the case where the intermediate layer 24 is composed of a single layer, the refraction of light incident on the intermediate layer 24 can be precisely controlled in stages. Furthermore, the first layer 30 and the second layer 32 are just examples; as long as there are multiple layers with a refractive index decreasing from the first blazed element 20 side to the second blazed element 22 side, there can be three or more layers. Moreover, the intermediate layer 24 does not need to be divided into multiple layers, and the refractive index can be continuously varied.

[0122] Furthermore, in the above embodiment, an example was described in which the intermediate layer 24 was immersed in the biconcave lens 16 and irradiated with ultraviolet light (UV), thereby integrally joining the second blaze member 22 and the biconcave lens 16 with respect to the intermediate layer 24. However, the technology of the present invention is not limited to this. For example, a mold for molding the second blaze member 22 can be used to first join the second blaze member 22 with the intermediate layer 24, and then join the concave surface 16A of the biconcave lens 16 with the second blaze member 22.

[0123] Furthermore, in the above embodiments, an example of irradiating ultraviolet (UV) light from the concave surface 16B side is given (see reference). Figure 13 The invention has been described, but the technology is not limited thereto. For example, ultraviolet (UV) light can be irradiated from the plane 14B side of the plano-convex lens 14. In this case, it is sufficient to irradiate UV light with a wavelength that can pass through the first blaze member 20 and the intermediate layer 24.

[0124] Furthermore, while ultraviolet-curable resins 38, 44, 46, and 48 were exemplified in the above embodiments, the technology of the present invention is not limited thereto. For example, it may be a photocurable resin that reacts with light of a different wavelength than ultraviolet light, or it may be a thermocurable resin.

[0125] Furthermore, in the above embodiment, a pair of lenses are used for the bonding optical element 10, but the technology of the present invention is not limited to this. Any optical element that allows light to pass through can be an optical element other than a lens.

[0126] Furthermore, while the above embodiments illustrate a film-forming method based on spin coating, the technology of the present invention is not limited to this, and film-forming methods based on spraying or inkjet printing can also be used. Additionally, the intermediate layer 24 can be fabricated using inorganic materials such as SiO2, TiO2, or MgF2. When coating inorganic materials, vapor deposition or similar methods are preferred.

[0127] Furthermore, in the above embodiment, an example was given in which the refractive index of the multiple layers (mediums) formed from the first blazing member 20 to the second blazing member 22 on the side where the subject light is incident decreases from the side of the first blazing member 20 to the side of the second blazing member 22. However, the technology of the present invention is not limited to this. Regardless of the incident direction of the subject light, even if the refractive index of the multiple layers decreases from the side of the second blazing member 22 to the side of the first blazing member 20, the same effect as the above embodiment can be obtained.

[0128] Furthermore, while the above embodiment has described the bonding optical element 10, the technology of the present invention is not limited thereto, and can also be applied to diffractive multifocal intraocular lenses. As an example, such as... Figure 20 As shown, a diffractive multifocal intraocular lens 58, as an example of a "blazed diffractive optical element" according to the technology of the present invention, is fitted into the eyeball 60 (hereinafter also referred to as "intraocular") for use. For example, it is implanted into the eye in place of a lens that is cloudy due to cataracts. Figure 20 In the example shown, a diffractive multifocal intraocular lens 58 is used instead of a lens. Thus, the diffractive multifocal intraocular lens 58 is used instead of a lens, and a blazing grating is etched on the surface of the diffractive multifocal intraocular lens 58 (the side in contact with the aqueous humor). Therefore, the surface of the diffractive multifocal intraocular lens 58 is in direct contact with the aqueous humor (hereinafter also referred to as "aqueous humor") 64 filling the anterior chamber 62.

[0129] The diffractive multifocal intraocular lens 58 includes a blaze element 66 and a surface layer 68. The blaze element 66 corresponds to the second blaze element 22 described in the above embodiment, and the surface layer 68 corresponds to the intermediate layer 24 described in the above embodiment. Furthermore, the surface layer 68 is an example of a "layer" as understood in this invention.

[0130] The shimmering component 66 forms a serrated surface 66A corresponding to the second serrated surface 22A described in the above embodiment. The serrated surface 66A is formed by a steep slope surface 66A1 and a gentle slope surface 66A2. The steep slope surface 66A1 is an inclined surface corresponding to the second steep slope surface 22A1 described in the above embodiment, and the gentle slope surface 66A2 is an inclined surface corresponding to the second gentle slope surface 22A2 described in the above embodiment.

[0131] exist Figure 20In the example shown, the back surface 68A of the surface layer 68 is joined to the serrated surface 66A, and the surface 68B of the surface layer 68 contacts the pre-aqueous humor 64. The surface layer 68 is formed in a shape corresponding to the serrated surface 66A. That is, the surface 68B exists at a position offset from the serrated surface 66A towards the pre-aqueous humor 64 by the thickness t described in the above embodiment, and is formed in the same shape (serrated) as the serrated surface 66A. Therefore, the portion of the pre-aqueous humor 64 that contacts the surface 68B is formed in the same shape as the first serrated surface 20A described in the above embodiment.

[0132] When the refractive index of the pre-aqueous humor 64 is set to A (e.g., around 1.34), the refractive index of the surface layer 68 is set to B, and the refractive index of the blazing element 66 is set to C, the refractive indices B and C are determined such that the relationship "A < B < C" holds true among the refractive indices A of the pre-aqueous humor 64, B of the surface layer 68, and C of the blazing element 66. That is, the pre-aqueous humor 64 corresponds to the second blazing element 22 described in the above embodiment, the blazing element 66 corresponds to the first blazing element 20 described in the above embodiment, and the surface layer 68 corresponds to the first blazing element 20 described in the above embodiment. This corresponds to the intermediate layer 24 described in the method. Therefore, the same effect as in the above embodiment can be obtained. Furthermore, the surface layer 68 can also be a multilayered structure, similar to the intermediate layer 24. Moreover, the surface layer 68 does not need to be divided into multiple layers, and its refractive index can change continuously. For example, the surface layer 68 can have a refractive index distribution such that the refractive index changes continuously from the pre-aqueous humor 64 to the blazing member 66; the closer to the pre-aqueous humor side, the closer the refractive index is to the refractive index A of the pre-aqueous humor 64; and the closer to the blazing member 66 side, the closer the refractive index is to the refractive index C of the surface layer 68, and this change is continuous.

[0133] Furthermore, while an example of implanting a diffractive multifocal intraocular lens 58 into the eye has been described here, the technology of the present invention is not limited thereto. For example, the diffractive multifocal intraocular lens 58 can be applied to an eye model 70. In this case, a liquid 74 having the same refractive index as the anterior chamber water 64 can be sealed into the simulated anterior chamber 72 of the eye model 70.

[0134] The eye model 70 may be, for example, an eye model used in the experimental phase of manufacturing a device for diagnosing or treating diabetic retinopathy or retinal detachment (e.g., an ophthalmic observation device or an ophthalmic laser therapy device), or an eye model used by medical students or doctors in skills training for performing various ophthalmic surgeries or observations.

[0135] Furthermore, the technology of the present invention can be appropriately combined with the above-described embodiments and various modifications. Moreover, it is not limited to the above-described embodiments; various structures can certainly be adopted as long as the spirit remains unchanged.

[0136] The descriptions and illustrations above are detailed explanations of a portion of the technology involved in this invention, and are merely one example of the technology of this invention. For example, the descriptions related to the above-described structure, function, effect, and effect are examples of the structure, function, effect, and effect of the portion involved in the technology of this invention. Therefore, without departing from the technical spirit of this invention, unnecessary parts may be deleted from the descriptions and illustrations above, or new elements may be added or replaced. Furthermore, to avoid complications and to facilitate understanding of the portion involved in the technology of this invention, descriptions related to common technical knowledge that does not require special explanation in aspects enabling the implementation of this invention have been omitted from the descriptions and illustrations above.

[0137] In this specification, "A and / or B" has the same meaning as "at least one of A and B". That is, "A and / or B" can mean only A, only B, or a combination of A and B. Furthermore, in this specification, the same approach applies to situations where three or more items are connected by "and / or".

[0138] All documents, patent applications and technical standards described in this specification, and the specific and separately described documents, patent applications and technical standards incorporated herein by reference, are incorporated herein by reference to the same extent.

Claims

1. A blazed diffraction optical element comprising: a blazed grating pair having a first blazed member and a second blazed member and functioning as a grating through the first blazed member and the second blazed member; and an intermediate layer between the first blazed member and the second blazed member, wherein a refractive index of the first blazed member is set as Na, a refractive index of the intermediate layer is set as N, and a refractive index of the second blazed member is set as Nb, a magnitude relation of Na > N > Nb is satisfied, a grating height of the first blazed member and the second blazed member is set as h, a thickness of the intermediate layer is set as t, and a critical angle is set as θc, an inequality of h < t tan θc and an equation of θc = asin(Nb / Na) are satisfied.

2. The blazed diffraction optical element according to claim 1, wherein the first blazed member has a first serrated face, the second blazed member has a second serrated face, and the first serrated face and the second serrated face complementarily engage via the intermediate layer.

3. The blazed diffraction optical element according to claim 1, wherein the first blazed member has a first serrated face, the second blazed member has a second serrated face, the first serrated face is formed by a first steep slope face and a first gentle slope face which is gentler in gradient than the first steep slope face, the second serrated face is formed by a second steep slope face and a second gentle slope face which is gentler in gradient than the second steep slope face, and the intermediate layer is disposed between the first steep slope face and the second steep slope face between the first serrated face and the second serrated face.

4. The blazed diffraction optical element according to claim 2, wherein the first serrated face is formed by a first steep slope face and a first gentle slope face which is gentler in gradient than the first steep slope face, the second serrated face is formed by a second steep slope face and a second gentle slope face which is gentler in gradient than the second steep slope face, and the intermediate layer is disposed between the first steep slope face and the second steep slope face between the first serrated face and the second serrated face.

5. The blazed diffraction optical element according to claim 3, wherein the first blazed member has a first reference face, the second blazed member has a second reference face, the first steep slope face and the first gentle slope face are faces which rise from the first reference face, the second steep slope face and the second gentle slope face are faces which rise from the second reference face, the first steep slope face is perpendicular to the first reference face, and the second steep slope face is perpendicular to the second reference face.

6. The blazed diffraction optical element according to claim 2, wherein the first serrated face and the second serrated face engage with a displacement of an amount of the thickness of the intermediate layer.

7. The blazed diffraction optical element according to claim 1, wherein the intermediate layer is composed of a plurality of layers having a refractive index which decreases from the first blazed member side to the second blazed member side.

8. The blazed diffraction optical element according to claim 1, wherein the intermediate layer is formed in a film shape.

9. The blazed diffraction optical element according to claim 1, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The grating height of the first blazed member is the same as the grating height of the second blazed member.

10. A blazed diffractive optical element comprising: a blazed grating pair having a first blazed member and a second blazed member and functioning as a grating by the first blazed member and the second blazed member; and an intermediate layer between the first blazed member and the second blazed member, a refractive index of the first blazed member is Na, a refractive index of the intermediate layer is N, and a refractive index of the second blazed member is Nb, a relationship of Na>N>Nb is satisfied, the first blazed member has a first serrated face, the second blazed member has a second serrated face, the first serrated face is formed of a first steep slope face and a first gentle slope face which is gentler in gradient than the first steep slope face, the second serrated face is formed of a second steep slope face and a second gentle slope face which is gentler in gradient than the second steep slope face, between the first serrated face and the second serrated face, a thickness of the intermediate layer between the first steep slope face and the second steep slope face is t, a grating height of the first blazed member and the second blazed member is h, and a critical angle is θc, an inequality of h 11. The blazed diffractive optical element according to any one of claims 1 to 10, wherein a blaze angle of the first blazed member and a blaze angle of the second blazed member are the same.

12. A blazed diffractive optical element comprising: a blazed member; and a layer provided on the blazed member, a refractive index of the layer is between a refractive index of the blazed member and a refractive index of an environment around the blazed member, the environment around the blazed member is aqueous humor in an eye, the refractive index of the layer is between the refractive index of the blazed member and the refractive index of the aqueous humor, a refractive index of the aqueous humor is A, a refractive index of the layer is B, and a refractive index of the blazed member is C, a relationship of A a grating height of the blazed member is h, a thickness of the layer is t, and a critical angle is θc, an inequality of h 13. The blazed diffractive optical element according to claim 12, wherein the blazed member has a serrated face, the layer is formed on the serrated face in a shape corresponding to the serrated face.

14. The blazed diffractive optical element according to claim 13, wherein the serrated face is formed of a steep slope face and a gentle slope face which is gentler in gradient than the steep slope face.

15. The blazed diffractive optical element according to claim 14, wherein the blazed member has a reference face, the steep slope face and the gentle slope face are faces rising from the reference face, the steep slope face is perpendicular to the reference face.

16. The blazed diffractive optical element according to claim 13, wherein the serrated face and the aqueous humor contact with an amount of the thickness of the layer.

17. The blazed diffractive optical element according to claim 12, wherein The layer is composed of a plurality of layers having a refractive index that increases from the anterior chamber water side to the blaze member side.

18. The blaze diffractive optical element according to claim 12, wherein The layer is formed in a film shape.

19. A manufacturing method of a blaze diffractive optical element, comprising: a step of forming a first blaze member; a step of forming an intermediate layer in a blaze portion of the first blaze member; and a step of forming a second blaze member paired with the first blaze member on a side of the intermediate layer opposite to the first blaze member side, a refractive index of the first blaze member is set as Na, a refractive index of the intermediate layer is set as N, and a refractive index of the second blaze member is set as Nb, a size relationship of Na>N>Nb is established, the intermediate layer is formed to have a thickness as follows: a grating height of the first blaze member and the second blaze member is set as h, a thickness of the intermediate layer is set as t, and a critical angle is set as θc, an inequality of h 20. The manufacturing method of a blaze diffractive optical element according to claim 19, wherein the step of forming the intermediate layer is a step of forming the intermediate layer using spin coating.

21. The manufacturing method of a blaze diffractive optical element according to claim 19 or 20, wherein the first blaze member has a first serrated surface, the second blaze member has a second serrated surface, in the step of forming the second blaze member, the first serrated surface and the second serrated surface are engaged with being offset by an amount of the thickness of the intermediate layer.

Images