WO2014050308A1

WO2014050308A1 - Diffraction optical element and method and device for producing diffraction optical element

Info

Publication number: WO2014050308A1
Application number: PCT/JP2013/070992
Authority: WO
Inventors: 佐々木俊央; 望月英宏
Original assignee: 富士フイルム株式会社
Priority date: 2012-09-27
Filing date: 2013-08-02
Publication date: 2014-04-03

Abstract

A diffraction optical element (E) provided with a polymer material layer (20), wherein: the polymer material layer (20) comprises a polymer material and a pigment, said pigment being dispersed in the polymer material layer (20) or covalently bonded to the polymer material in the polymer material layer (20); and a diffraction optical element pattern configured of dot-shaped openings (concave portions (31)) and/or convex portions is arranged at the interface of the polymer material layer (20). To produce the diffraction optical element (E), the interface of the polymer material layer (20) is deformed by irradiating the neighborhood of the interface with a laser light having a wavelength that is absorbed by the pigment, and the irradiation is conducted at the interface in a preset pattern so as to form the dot-shaped openings and/or convex portions constituting the diffraction optical element pattern at the interface.

Description

Diffractive optical element, diffractive optical element manufacturing method and manufacturing apparatus

The present invention relates to a diffractive optical element that can be used as an image display device, a security element, an optical filter element, and the like, and a manufacturing method and a manufacturing apparatus of the diffractive optical element.

Conventionally, as a method for manufacturing a diffractive optical element, a method is known in which fine exposure is performed on a photoresist to create a mask, and unevenness is formed by etching (Patent Document 1). In addition, a method of manufacturing a diffractive optical element by forming a fine uneven shape by laser ablation by irradiating the surface of a polymer material with laser light is also known (Patent Document 2).

Japanese Patent Laid-Open No. 2003-220478 JP 2000-147228 A

However, creating a mask and performing etching as in the method of Patent Document 1 requires many steps. On the other hand, when processing is performed by laser ablation as in the method of Patent Document 2, etching is not required, but since a large amount of energy is required for processing, it is necessary to use a pulse laser or an ultraviolet laser, and processing time There is also a problem that it is long. In addition, the processing by laser ablation has a problem that it is difficult to perform a fine processing with a desired pattern, or to realize a gradation controlled pattern in a multi-stage shape that realizes a higher-precision diffractive optical element. is there.

It is one aspect of the aspects of the present invention to provide a diffractive optical element that can be manufactured easily and at high speed, and a method and apparatus for manufacturing the diffractive optical element.

The diffractive optical element according to one embodiment of the present invention includes a polymer material layer, and the polymer material layer is dispersed in the polymer material and the polymer material layer, or the polymer material layer And a dye which is covalently bonded to a molecular material, and a diffractive optical element pattern having dot-like openings and / or convex portions is arranged at the interface of the polymer material layer.

According to such a diffractive optical element, at the time of manufacture, the dye contained in the polymer material layer absorbs laser light, thereby giving energy to the polymer material layer with high efficiency and opening the interface at the polymer material layer. It is also possible to form a diffractive optical element pattern by forming convex portions. Therefore, it is not necessary to perform etching, and it can be easily manufactured in a short irradiation time. Further, since the openings and / or convex portions are formed by deforming the interface rather than peeling the material as in laser ablation, it is possible to form a diffractive optical element pattern that can be finely controlled in gradation. . The opening referred to in the present invention may be a bottomed recess or may penetrate the polymer material layer.

In the above-described diffractive optical element, the dye may include a one-photon absorption dye. When the dye contains a one-photon absorption dye, it can be processed with a low energy laser such as a semiconductor laser.

In the diffractive optical element described above, the dye may include a multiphoton absorbing dye. When a multiphoton absorbing dye is included, a diffractive optical element having high transmittance in the visible wavelength region can be obtained.

The diffractive optical element described above can have a support that supports the polymer material layer. By providing the support, it is possible to reduce the cost by thinning the polymer material layer.

The diffractive optical element described above preferably includes a cover layer on the side where the openings and / or convex portions of the polymer material layer are arranged. When the cover layer is provided on the side where the openings and / or convex portions are arranged, the functions of the diffractive optical element can be maintained by protecting the openings and / or convex portions.

In the diffractive optical element described above, there are a plurality of types of openings and / or projections having different depths or heights, and a multi-value diffractive optical element pattern is formed by the plurality of types of openings and / or projections. It can be set as a structure. By configuring the multi-value diffractive optical element pattern in this way, it is possible to enhance the function of the diffractive optical element, such as removing unnecessary diffraction images. In order to change the depth or height of the opening and / or the convex portion, it is only necessary to adjust the irradiation time of the laser beam. Therefore, a highly functional diffractive optical element can be easily manufactured. it can.

In the above-described diffractive optical element, it is desirable that the dye has an absorption wavelength band of mainly 450 nm or less and a light transmittance of a wavelength of 450 to 800 nm of 50% or more. That is, the dye mainly absorbs light in a wavelength region of 450 nm or less, whereby a diffractive optical element that is relatively colorless (highly transmissive in the visible wavelength region) can be obtained.

According to another aspect of the present invention, there is provided a method for manufacturing a diffractive optical element, comprising: preparing a polymer material layer having a polymer material in which a dye is dispersed or a polymer material having a dye covalently bonded; Dot-shaped openings and / or protrusions that form a diffractive optical element pattern at the interface by irradiating laser light having a wavelength that is absorbed by the dye in the vicinity to deform the interface and performing this irradiation at the interface in a predetermined pattern It is characterized by forming.

According to such a manufacturing method, energy can be given to the polymer material layer with high efficiency by absorbing the laser light to the dye contained in the polymer material layer. Therefore, etching is not required, and a diffractive optical element can be easily manufactured in a short irradiation time. Further, since the diffractive optical element pattern is formed at the interface by scanning the laser beam on the interface, it is not necessary to use a mask as in the prior art. Furthermore, since the openings and / or projections are formed by deforming the interface rather than peeling the material as in laser ablation, it is possible to form an optical element pattern that is fine and can be controlled in gradation.

In the above-described method, it is desirable that the irradiation time of the laser beam for forming one opening or convex portion is 120 μsec or less. By shortening the irradiation time, the diffractive optical element can be manufactured at high speed.

In the above-described method, it is desirable that the reflected light from the interface is detected by the sensor during the irradiation of the laser light, and the focal position of the laser light is adjusted to a predetermined position based on the output signal of the sensor. In this way, by adjusting the focal position based on the reflected light from the interface, it is possible to obtain a diffractive optical element with desired performance by aligning the size of the opening or the recess.

According to still another aspect of the present invention, there is provided a diffractive optical element manufacturing apparatus for forming a diffractive optical element pattern on a polymer material layer having a polymer material in which a dye is dispersed or a polymer material to which a dye is covalently bonded. The diffractive optical element manufacturing apparatus includes a light source that emits laser light having a wavelength that is absorbed by the dye, a deflector that deflects the laser light emitted from the light source, and a laser beam deflected by the deflector as a polymer material. An image forming optical system for forming an image near the interface of the layer, and a control device for controlling the output of the light source and the deflector. The control device is a dot that forms a diffractive optical element pattern at the interface of the polymer material layer. The output of the light source is changed in synchronism with the scanning of the laser beam on the interface of the polymer material layer by controlling the deflector so as to form an opening and / or a convex portion. With features That.

According to such a manufacturing apparatus, an optical diffractive element can be manufactured by changing the output of a light source while scanning a laser beam with a deflector and forming an opening and / or a convex portion at the interface of the polymer material layer. it can. Further, since the diffractive optical element pattern is formed at the interface by scanning the laser beam on the interface, it is not necessary to use a mask as in the prior art. Furthermore, in this manufacturing apparatus, since the diffractive optical element pattern is formed by scanning the laser beam on the interface with a deflector, it is not necessary to move the polymer material layer during processing. The manufacturing apparatus irradiates the polymer material layer containing the dye with laser light to form openings and / or projections, so that the output of the laser light can be reduced and the processing can be performed at high speed. .

In the manufacturing apparatus described above, it is desirable that the imaging optical system includes an objective lens and at least two condenser lenses. By using such an optical system including the objective lens and the two condensing lenses, it is possible to form a fine optical diffraction element pattern reduced with a simple configuration.

In the manufacturing apparatus described above, it is desirable that the irradiation time of the laser light for forming one opening or convex portion is 120 μsec or less. By shortening the irradiation time, the diffractive optical element can be manufactured at high speed.

In the manufacturing apparatus described above, the imaging optical system preferably includes an objective lens, and the objective lens preferably has a numerical aperture of 0.13 or more. Thereby, a laser beam can be condensed small and an opening and / or a convex part can be formed.

The manufacturing apparatus described above further includes a sensor that detects the laser light reflected at the interface, and the control apparatus controls the imaging optical system based on the output signal of the sensor to adjust the focal position of the laser light to a predetermined position. It is desirable to be configured as follows.

As described above, by adjusting the focal position based on the laser beam reflected at the interface, the size of the opening or the concave portion is made uniform, and a diffractive optical element having a desired performance can be obtained.

In the manufacturing apparatus described above, the wavelength of the laser light emitted from the light source is preferably 450 nm or less. By using a laser having such a wavelength, a dye that does not absorb much visible light can be used as a dye, so that the diffractive optical element can be made relatively colorless.

In the manufacturing apparatus described above, it is desirable to have a transport device that moves the polymer material layer relative to the laser beam. A plurality of diffractive optical elements can be continuously manufactured by moving the polymer material layer by the transport device.

According to the diffractive optical element and the manufacturing method and manufacturing apparatus of the aspect as described above, the diffractive optical element can be easily manufactured in a short time. According to the method and apparatus for manufacturing a diffractive optical element, a diffractive optical element pattern is formed at the interface by scanning the interface with laser light, so that it is not necessary to use a mask as in the prior art. Further, according to the diffractive optical element manufacturing apparatus, the diffractive optical element pattern is formed by scanning the laser beam on the interface with the deflector, and therefore it is not necessary to move the polymer material layer during processing.

It is a perspective view of a diffractive optical element. It is a figure explaining the usage method of a diffractive optical element. It is a figure explaining the other usage method of a diffractive optical element. It is sectional drawing of the diffractive optical element of 1st Embodiment. It is sectional drawing of the diffractive optical element of 2nd Embodiment. It is sectional drawing of the diffractive optical element of 3rd Embodiment. It is sectional drawing of the diffractive optical element of 4th Embodiment. It is sectional drawing of the diffractive optical element of 5th Embodiment. It is sectional drawing of the diffractive optical element of 6th Embodiment. It is sectional drawing of the diffractive optical element of 7th Embodiment. It is sectional drawing of the diffractive optical element of 8th Embodiment. It is a block diagram of the manufacturing apparatus of a diffractive optical element. It is a perspective view explaining a conveying apparatus. It is a figure explaining the imaging optical system of a manufacturing apparatus. FIG. 5 is a simulation result of a reproduced image using the (a) design original image, (b) phase pattern, and (c) (b) phase pattern in the diffractive optical element of Example 1 displaying an image as a diffraction image. . 2 is a laser microscope image of the diffractive optical element of Example 1. FIG. FIG. 17 is a laser microscope image of the diffractive optical element of Example 1 in which a part of the visual field in FIG. 16 is enlarged. 2 is a cross-sectional profile of a concave portion of the diffractive optical element of Example 1. 2 is a reproduced image using the diffractive optical element of Example 1. FIG. It is the reproduction | regeneration image of the diffractive optical element of Example 2 which comprised the binary diffraction grating. It is the reproduction | regeneration image of the diffractive optical element of Example 2 which comprised the ternary diffraction grating. 4 is an atomic force microscope image of the diffractive optical element of Example 3. FIG. 10 is a cross-sectional profile of a convex portion of a diffractive optical element of Example 3.

Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the diffractive optical element E of the present invention is a diffractive optical element pattern formed by forming fine dot-shaped openings and / or convex portions in a predetermined range of a sheet-like member. In FIG. 1, the pattern area PA on which the diffractive optical element pattern is formed has a square as an example, but the shape of the pattern area PA is not particularly limited. However, from the viewpoint of obtaining a large number of diffractive optical elements E from a small amount of material (a polymer material layer described later), it is efficient to form the pattern area PA as a square with a predetermined gap between adjacent diffractive optical elements. Is.

In the present embodiment, as the diffractive optical element E, an element that obtains a diffracted image that becomes a predetermined image by applying a laser beam is exemplified. For example, as shown in FIG. 2, the diffractive optical element E is arranged in the order of the reproduction laser L2, the diffractive optical element E, and the screen SC, and emits the reproduction laser light LB2 from the reproduction laser L2. The laser beam LB2 for use is passed through the pattern area PA to obtain the diffracted light DB. In this manner, the diffracted light DB displays a predetermined image by irradiating the pattern region PA with the reproduction laser beam LB2.
The diffractive optical element E can also be used as shown in FIG. That is, the reproducing laser L2, the screen SC, and the diffractive optical element E are arranged in this order, and the hole SC1 is formed in the screen SC. Then, the reproducing laser beam LB2 emitted from the reproducing laser L2 is applied to the pattern area PA of the diffractive optical element E through the hole SC1. In this way, the reproduction laser beam LB2 is diffracted by the diffractive optical element pattern while being reflected at the interface where the diffractive optical element pattern of the diffractive optical element E is formed, and displays a predetermined image on the screen SC. be able to.

Next, various embodiments of the diffractive optical element E of the present invention will be described with reference to cross-sectional views, respectively.

[First Embodiment]
As shown in FIG. 4, the diffractive optical element E according to the first embodiment has a structure composed of two layers in which a polymer material layer 20 is provided on a support 10.

The support 10 is a member for supporting the polymer material layer 20.
The material of the support 10 is not particularly limited, but is made of a material that can transmit the reproducing laser beam LB2 of the reproducing laser L2 as an example because the reproducing laser beam LB2 is transmitted therethrough. However, the support 10 may be a member that is opaque to the reproduction laser beam LB2. For example, the support 10 may be a metal plate, and the surface of the support 10 on the polymer material layer 20 side may be used as a reflection surface.
The thickness of the support 10 is not particularly limited as long as it has sufficient mechanical properties to support the polymer material layer 20, and may be a film of about 1 mm or less, for example, about 1 mm or more. A plate-like member may be used.

The polymer material layer 20 has a diffractive optical element pattern formed by dot-like openings and / or convex portions (hereinafter, sometimes referred to as “lattice points”) at the interface, here the interface 21 with the air layer. It is a layer to be formed. In the example of FIG. 4, a plurality of recesses 31 are formed as an example of the opening. The concave portions 31 in FIG. 4 are dot-like when viewed in plan, and all have substantially the same depth and diameter. The diffractive optical element pattern is designed according to a desired reproduced image, and is, for example, a pattern like the laser microscope image of FIGS.

The polymer material layer 20 has a dispersed dye or a dye covalently bonded to the polymer material in the polymer material layer 20. When the dye is covalently bonded to the polymer material, it prevents the precipitation and elution of the dye due to long-term storage, and can reduce the time-dependent change in optical properties such as transmittance and reflectance, and has excellent long-term storage A diffractive optical element can be constructed.

The dye herein can include a one-photon absorbing dye and / or a multi-photon absorbing dye. When a one-photon absorption dye is included, it can be processed with a low energy laser such as a semiconductor laser. On the other hand, when a multiphoton absorbing dye is included, the diffractive optical element E1 having high transparency in the visible wavelength region can be configured. The one-photon absorption dye is preferably a one-photon absorption compound that does not have a linear absorption band at the wavelength of the reproduction laser beam LB2, and the multiphoton absorption dye does not have a linear absorption band at the wavelength of the reproduction laser light LB2. A multiphoton absorbing compound is preferred.

The absorptance (one-photon absorptance) of the polymer material layer 20 with respect to laser light (recording laser light) for forming lattice points is desirably 5% or more per 1 μm thickness, and is 10% or more. Is more desirable. The higher the absorptance, the faster the temperature of the polymer material can be increased when the recording laser light is irradiated, the diffractive optical element E1 can be formed in a short time, and a low energy laser light source is used. be able to.

The formation method of the polymer material layer 20 is not particularly limited, but the polymer material layer 20 can be formed by spin coating or blade coating using a solution obtained by dissolving a dye material and a polymer material in a solvent. As the solvent at this time, dichloromethane, chloroform, methyl ethyl ketone (MEK), acetone, methyl isobutyl ketone (MIBK), toluene, hexane, or the like can be used.

Polymer materials used for the polymer material layer 20 include polyvinyl acetate (PVAc), polymethyl methacrylate (PMMA), polyethyl methacrylate, polybutyl methacrylate, polybenzyl methacrylate, polyisobutyl methacrylate, polycyclohexyl methacrylate, polycarbonate (PC ), Polystyrene (PS), polyvinyl chloride (PVC), polyvinyl alcohol (PVA), and the like.
The range of the molecular weight Mw of the polymer material (or polymer material to which a dye is covalently bonded) in the polymer material layer 20 is preferably 10,000 to 1,000,000. If the molecular weight is lower than 10,000, the fluidity of the polymer material itself becomes high, so that bleeding (diffusion) to an adjacent layer such as a support or a cover layer occurs, which may cause a problem in storage stability. On the other hand, when the molecular weight is higher than 1,000,000, there is a possibility that the viscosity becomes excessively high and uniform film formation becomes difficult during the coating formation of the polymer material layer. The molecular weight Mw can be measured by gel permeation chromatography (GPC).
The glass transition point Tg of the polymer material is preferably 60 ° C. or higher, and more preferably 100 ° C. or higher. Since the glass transition point Tg is high, the thermal stability is improved, the shape change of the interface after processing is suppressed, and the characteristics of the diffractive optical element can be stably maintained for a long period of time. The glass transition point Tg of the polymer material is preferably 300 ° C. or lower in order to realize high-speed processing of lattice points.

In addition, the dye dispersed in the polymer material or the dye covalently bonded to the polymer material is a methine dye (cyanine dye, hemicyanine dye, styryl dye, oxonol dye, merocyanine dye, etc.) as long as it is a one-photon absorption dye. , Macrocyclic dyes (phthalocyanine dyes, naphthalocyanine dyes, porphyrin dyes, etc.), azo dyes (including azo metal chelate dyes), arylidene dyes, complex dyes, coumarin dyes, azole derivatives, triazine derivatives, benzotriazole derivatives, benzophenone derivatives, phenoxy Sazine derivatives, phenothiazine derivatives, 1-aminobutadiene derivatives, cinnamic acid derivatives, quinophthalone dyes, and the like can be used. Among these, triazine derivatives, benzotriazole derivatives, and benzophenone derivatives are ultraviolet absorbing dyes, the absorption wavelength band is mainly 450 nm or less, and the light transmittance at a wavelength of 450 to 800 nm is 50% or more. Therefore, when these dyes are used, light in a wavelength region of 450 nm or less is mainly absorbed, so that a relatively colorless diffractive optical element E1 can be configured.

In the case of using a multiphoton absorption dye, the dye compound is not particularly limited as long as it does not have a linear absorption band at the wavelength of the reproduction laser beam LB2. For example, the dye compound is represented by the following general formula (1). Examples thereof include compounds having a structure.

(In the general formula (1), X and Y each represent a substituent having a Hammett's sigma para value (σp value) of zero or more, which may be the same or different, and n represents an integer of 1 to 4. R represents a substituent, which may be the same or different, and m represents an integer of 0 to 4.)

In the general formula (1), X and Y are those having a positive σp value in the Hammett formula, so-called electron-withdrawing groups, and preferably, for example, a trifluoromethyl group, a heterocyclic group, a halogen atom, a cyano group Nitro group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, carbamoyl group, acyl group, acyloxy group, alkoxycarbonyl group, etc., more preferably trifluoromethyl group, cyano group, acyl group, acyloxy group, Or an alkoxycarbonyl group, and most preferably a cyano group or a benzoyl group. Among these substituents, an alkylsulfonyl group, an arylsulfonyl group, a sulfamoyl group, a carbamoyl group, an acyl group, an acyloxy group, and an alkoxycarbonyl group are further added for various purposes in addition to imparting solubility to a solvent. It may have a substituent, and preferred examples of the substituent include an alkyl group, an alkoxy group, an alkoxyalkyl group, and an aryloxy group.

n is preferably 2 or 3, most preferably 2. As n becomes 5 or more, linear absorption comes out on the longer wavelength side, and non-resonant two-photon absorption recording using recording light in a wavelength region shorter than 700 nm becomes impossible.
R represents a substituent, and the substituent is not particularly limited, and specific examples include an alkyl group, an alkoxy group, an alkoxyalkyl group, and an aryloxy group.

Specific examples of the compound having the structure represented by the general formula (1) are not particularly limited, but compounds represented by the following chemical structural formulas D-1 to D-21 can be used.

Further, as the polymer material to which the dye is covalently bonded, for example, a compound represented by the following general formula (2) can be used.

(In general formula (2), Y represents a substituent in which both Hammett's sigma para value (σp value) has a value of zero or more, and X also represents the same kind of substituent. N represents an integer of 1 to 4, R1, R2, and R3 represent substituents, which may be the same or different, l represents 1 or more, and m represents an integer of 0 to 4.)

According to the diffractive optical element E1 having the above-described configuration, the concave portion 31 can be formed by condensing and irradiating the recording material laser beam on the polymer material layer 20, and the diffractive optical element E1 can be manufactured. At this time, the dye contained in the polymer material layer 20 is made to absorb the recording laser light, whereby energy can be given to the polymer material layer 20 with high efficiency, and the diffractive optical element E1 can be manufactured in a short time. In addition, the diffractive optical element E1 can be manufactured in a short time because etching is not necessary at the time of manufacture. Further, since the recess 31 is formed by deforming the interface rather than peeling the material as in laser ablation, a fine and gradation-controllable optical element pattern can be formed. Further, by supporting the polymer material layer 20 on the support 10, the polymer material layer 20 can be thinned, and the cost can be reduced.

[Second Embodiment]
Next, a second embodiment of the diffractive optical element E will be described. In each of the following embodiments, the polymer material layer 20 and the support 10 can adopt the same configuration as in the first embodiment.
As shown in FIG. 5, the diffractive optical element E2 of the second embodiment includes a support 10 and a polymer material layer 20, and lattice points on the opposite side of the polymer material layer 20 from the support 10 are arranged. A cover layer 41 is provided on the provided side. The cover layer 41 is for protecting the shape of the lattice points mechanically or chemically. The configuration of the cover layer 41 is not particularly limited as long as the lattice points are not adversely affected. For example, the cover layer 41 can be provided by applying and curing an ultraviolet curable resin. Although not shown, the cover layer 41 may be configured by attaching a film (such as polycarbonate) with an adhesive.

Further, unlike the first embodiment, the diffractive optical element E2 of the second embodiment has a lattice point constituted by a convex portion 32. Whether the lattice point is an opening or a convex portion is determined by the absorption energy (output, irradiation time and absorption rate) of the polymer material layer 20 when the recording laser beam is irradiated. If it is large, it tends to be an opening.

According to the diffractive optical element E2 having the above configuration, the cover layer 41 protects the lattice points and can be stored for a long time. The lattice points are preferably formed after the cover layer 41 is provided. By doing so, the shape of the lattice points is not disturbed when the cover layer 41 is provided, and the presence of air or the like between the cover layer 41 and the polymer material layer 20 can be suppressed.

[Third Embodiment]
As shown in FIG. 6, the diffractive optical element E <b> 3 according to the third embodiment has a form in which the lattice point is a hole 33 penetrating the polymer material layer 20 with respect to the first embodiment. Such holes 33 may be formed by thinly forming the polymer material layer 20 and exposing the polymer material layer 20 with large energy when forming lattice points. Even if such holes 33 are used as lattice points, the function of the diffractive optical element can be exhibited as in the first embodiment, and it can be manufactured easily and in a short time.

In the embodiment in which the hole 33 penetrating the polymer material layer 20 is formed, the dye of the polymer material layer 20 absorbs a lot of light in the visible wavelength region (for example, 50% or more). During reproduction, the reproduction laser beam LB2 can be passed through the hole 33, and the diffracted light of the light that has passed through the hole 33 can be used.

[Fourth Embodiment]
As shown in FIG. 7, the diffractive optical element E4 according to the fourth embodiment is obtained by eliminating the support 10 from the first embodiment, and instead of providing the support 10, the thickness of the polymer material layer 20 is increased. And the shape of the diffractive optical element E4 is maintained. The polymer material layer 20 may be a film of about 1 mm or less or a plate-shaped member of about 1 mm or more.

According to the diffractive optical element E4 having such a configuration, the manufacturing process can be simplified by omitting the support.

[Fifth Embodiment]
As shown in FIG. 8, the diffractive optical element E5 according to the fifth embodiment is different from the first embodiment in that the diffractive optical element E5 has lattice points on the inner interface on the support side instead of the interface with the air of the polymer material layer 20. A recess 31 is formed. In this embodiment, an adhesive that is a layer softer than the polymer material layer 20 (for example, having a low glass transition point Tg) between the support 10 and the polymer material layer 20 so that the inner interface is easily deformed. Layer 42 is interposed. Thus, when forming a lattice point at the inner interface of the polymer material layer 20, the recording laser beam may be condensed and irradiated near the inner interface. As a matter of course, the lattice points may be convex when viewed from the polymer material layer 20 (may project from the polymer material layer 20).

According to the diffractive optical element E5 having such a configuration, since the support 10 functions as a cover layer and the lattice points are not exposed on the outermost surface, the shape of the lattice points can be changed without providing the cover layer 41 separately. Can be protected.

[Sixth Embodiment]
As shown in FIG. 9, the diffractive optical element E6 according to the sixth embodiment is different from the first embodiment in that a reflective layer 43 is provided on the outer surface of the polymer material layer 20. The reflective layer 43 may be a metal thin film, or may be a layer made of a material having a refractive index significantly different from that of the polymer material layer 20. According to the diffractive optical element E6 having such a configuration, as indicated by an arrow in FIG. 9, the reproducing laser beam LB2 is reflected by the reflective layer 43, and the reproducing laser beam LB2 is incident on the diffractive optical element E6. A reproduced image can be formed. In FIG. 9, the reproduction laser beam LB2 is irradiated from the outside (upper side of the drawing) of the reflective layer 43, but the reproduction laser beam LB2 is irradiated from the opposite side (lower side of the drawing). I do not care.

[Seventh Embodiment]
As shown in FIG. 10, the diffractive optical element E7 according to the seventh embodiment is different from the first embodiment in that the grating point is not limited to the concave portion 31 having a constant depth, but different depths, for example, the concave portion 31. The deep concave portions 31B are mixed and arranged. In order to make the depths of the recesses different, it is only necessary to make the irradiation time of the recording laser light different during manufacture. When the recording laser light is irradiated for a short time, a shallow concave portion is formed, and when irradiated for a long time, a deep concave portion is formed.

As described above, when there are the concave portions 31 and the concave portions 31B having different depths, when the reproduction laser beam LB2 is diffracted at each lattice point during use, the optical path length of the diffracted light is different at each lattice point. The diffraction angle, which is the traveling direction determined by the interference of the reproduction laser beam LB2 diffracted by a plurality of lattice points, can be adjusted. For this reason, the multi-valued diffraction grating using the concave portion 31 and the concave portion 31B can give variations to the image, such as fading the inverted image or the secondary diffraction image.
In addition, although the case where the recesses 31 and the recesses 31B having two kinds of depths are mixed in the lattice point is illustrated here, the recesses having three or more kinds of depths may be mixed.

[Eighth Embodiment]
As shown in FIG. 11, the diffractive optical element E8 according to the eighth embodiment is obtained by arranging not only the concave portions 31 but also the convex portions 32 in the lattice points in the first embodiment.
As described above, when the concave portion 31 and the convex portion 32 are present, as in the seventh embodiment, when the reproduction laser beam LB2 is diffracted at each lattice point during use, the optical path length of the light diffracted at each lattice point is set. Since the difference is made, it is possible to adjust the diffraction angle, which is the traveling direction determined by the interference of the reproduction laser beam LB2 diffracted by a plurality of lattice points. For this reason, the multi-valued diffraction grating using the concave portion 31 and the convex portion 32 can give variations to the image, such as fading the inverted image or the secondary diffraction image.

In addition, although the case where the recessed part 31 and the convex part 32 were mixed was illustrated here at the lattice point, what further varied the depth of the recessed part 31 and the height of the convex part 32, and is multi-valued. A structured diffraction grating may be configured.

As can be seen from the descriptions of the seventh and eighth embodiments, there are a plurality of types of openings and / or projections constituting the lattice points, each having a different depth or height. A diffractive optical element pattern may be formed. In order to change the depth or height of the opening and / or the convex portion, it is only necessary to adjust the irradiation time of the recording laser beam, so that a highly functional diffractive optical element is easily manufactured. be able to.

Although various forms of the diffractive optical element E have been described above, the features of the diffractive optical elements E can be applied in combination with each other.

[Diffraction optical element manufacturing equipment]
Next, an apparatus for manufacturing the diffractive optical element E will be described.
As shown in FIG. 12, the manufacturing apparatus 50 mainly includes a recording laser 51 as a light source, a deflector 52, a stage 57, an imaging optical system 60, and a control device 59.

The recording laser 51 is a laser that emits the recording laser beam LB1, and is preferably a semiconductor laser. The wavelength of the recording laser beam LB1 is a wavelength that is absorbed by the dye in the polymer material layer 20 (one-photon absorption and / or multiphoton absorption), and the wavelength of the reproducing laser beam LB2 used when the diffractive optical element E is used. It is desirable to be different from the wavelength. Accordingly, since the diffractive optical element E is suppressed from being heated by the reproducing laser beam LB2 during reproduction, the reproducing laser beam LB2 having a large output can be used during reproduction.
In particular, when the diffractive optical element E for image display is manufactured, it is desirable that the diffractive optical element E has high transparency in the visible wavelength range. Therefore, the recording laser 51 has a wavelength of 450 nm or less. It is desirable that the laser beam LB1 is emitted.

In order to draw a fine diffraction pattern (reproduced image), the recording laser 51 is preferably a short wavelength laser capable of reducing the spot size of the recording laser beam LB1, and in particular, 400 to 410 nm. The semiconductor laser may be preferable.

When a multiphoton absorption dye is used as the dye in the polymer material layer 20, it is desirable to use a short pulse laser having a large peak power as the recording laser 51. It is desirable that the energy absorbed by the dye is large, and a pulse laser having a large average power that is a product of the peak power, the pulse width, and the repetition period is preferable. For example, the recording laser 51 may have an output with an average power of 10 mW or more, more preferably 100 mW or more. Note that, when a multiphoton absorption dye is used as the dye in the polymer material layer 20, a wavelength without linear absorption is used, so that it is easy to make a diffractive optical element E that is particularly highly transparent in the visible wavelength region.

The deflector 52 is a device that deflects the traveling direction of the recording laser light emitted from the recording laser 51, and a galvanometer mirror, a polygon mirror, a resonant mirror, or the like can be used. Alternatively, the deflector 52 may employ an electro-optic element (EO element) to deflect the traveling direction of the recording laser beam LB1.

The deflector 52 may deflect the recording laser beam LB1 in at least one direction. However, in the case of using a deflector that deflects in two directions, such as a biaxial galvanometer mirror, the material EM of the diffractive optical element E placed on the stage 57 (with no lattice points recorded) is not moved. A diffractive optical element pattern can be manufactured. When the deflector 52 that deflects only in one direction is used, the stage 57 may be configured so that the material EM can be conveyed in a direction orthogonal to the one direction.

The stage 57 is a table on which the material EM is placed. The stage 57 may be one that does not move while the material EM is fixed, but as shown in FIG. 13, it is desirable that the stage 57 is a transport stage configured to transport the material EM in one direction. For example, the transport stage 570 includes a winding roller 571 that winds the strip-shaped material EM and an unwinding roller 572 that transports the material EM while stretching the material EM between the winding roller 571 and the unwinding roller 572. It is. By adopting such a transport stage 570, the material EM is transported, and the deflector 52 scans the recording laser beam LB1 in a direction that intersects at least the transport direction of the transport stage 570 (for example, a direction orthogonal thereto). By doing so, the diffractive optical element E can be manufactured continuously. At this time, the deflector 52 may deflect the recording laser beam LB1 only in the direction intersecting the transport direction of the transport stage 570, or in the direction intersecting the transport direction of the transport stage 570 and in the transport direction. It may be deflected in both directions. In the latter case, the transport stage 570 is stopped while the one row of diffractive optical elements E is manufactured, and the transport stage 570 is operated each time the one row of diffractive optical elements E is manufactured to transport the material EM for one row. Good.

As shown in FIG. 12, the imaging optical system 60 includes a first condenser lens 61, a second condenser lens 62, and an objective lens 63. The first condenser lens 61 and the second condenser lens 62 are both lenses having the same focal length f, and constitute a so-called 4f optical system. The reflecting surface of the deflector 52 is disposed in the vicinity of the focal position on the front side of the first condenser lens 61. The objective lens 63 is a condensing lens that forms an image of the recording laser beam LB1 that has passed through the second condensing lens 62 in the vicinity of the interface of the polymer material layer 20, and is disposed at the focal position of the second condensing lens 62. ing. The objective lens 63 is provided with a focus actuator 63A. The objective lens 63 is preferably an fθ lens that is corrected so that the image height is proportional to the deflection angle in the scanning range. The objective lens 63 preferably has a numerical aperture of 0.13 or more. Thereby, the recording laser beam LB1 can be condensed to form fine lattice points.

As shown in FIG. 14, by using the 4f optical system, the recording laser beam LB1 having a predetermined beam diameter deflected by the deflector 52 passes through the first condenser lens 61 and is deflected. The image is once formed at an intermediate point between the first condenser lens 61 and the second condenser lens 62 in parallel with the traveling direction of the non-recording laser beam LB1. Then, after passing through the second condenser lens 62, at the focal position on the rear side of the second condenser lens 62, the same beam diameter and the same deflection angle as when exiting the deflector 52 are obtained. Further, the recording laser beam LB1 is narrowed down by the objective lens 63 at the focal position on the rear side so as to form an image in a minute spot shape on the image plane IM. With such an imaging optical system 60, the recording laser beam LB1 deflected by the deflector 52 can be scanned along the interface of the polymer material layer 20 with a simple configuration.

In FIG. 14, the 4f optical system having the simplest configuration is illustrated. However, for example, by forming the space between the biaxial reflecting mirrors of the deflector 52 with the 4f optical system, the aberration of the condensed spot in the laser scanning range is illustrated. It is also possible to make the imaging optical system 60 smaller by reducing the above-mentioned or by adopting an aspheric lens.

Returning to FIG. 12, between the recording laser 51 and the deflector 52, a PBS (polarized beam splitter) 54 and a quarter wavelength plate 55 are arranged in this order. In addition, a light receiving element 53 (sensor) for focusing is disposed on the side of the PBS 54.
The PBS 54 is an optical element that reflects and separates light of a specific polarization, passes the recording laser light LB1 emitted from the recording laser 51 and advances it toward the

quarter wavelength plate

55, and 1 / It fulfills the function of reflecting the light returned from the four-wavelength plate 55 and advancing it toward the light receiving element 53.

The quarter-wave plate 55 is an optical element that converts linearly polarized light into circularly polarized light and converts the circularly polarized light into linearly polarized light in a direction corresponding to the rotation direction, and the recording laser beam LB1 travels toward the deflector 52. Sometimes, the direction of polarized light differs by 90 ° between when reflected from the material EM and then returned from the deflector 52.

The control device 59 receives the signal from the light receiving element 53, controls the focus actuator 63A, and functions to adjust the focus of the recording laser beam LB1 near the interface of the polymer material layer 20 in the material EM. This focus adjustment is performed by adjusting the relative distance between the objective lens 63 and the polymer material layer 20 so that the intensity of the reflected light is maximized, or by one-dimensional or two-dimensional gain obtained by scanning the recording laser beam LB1. The contrast of the three-dimensional light intensity profile can be maximized, or a so-called astigmatism method can be used. The control device 59 operates the deflector 52 to scan the recording laser beam LB1 along the polymer material layer 20, and controls the output of the recording laser 51 based on the exposure data stored in advance. Thus, the output of the recording laser beam LB1 is modulated. When a pulse laser is employed as the recording laser 51, the mechanical laser is controlled to block the recording laser beam LB1, or preferably the electro-optic modulation element (EOM) is controlled for high-speed modulation. Then, the recording laser beam LB1 may be modulated by deflecting it.

It is desirable to synchronize the timing of the operation of the deflector 52 and the modulation thereof. This synchronization can be performed, for example, by detecting a part of the recording laser beam LB1 deflected by the deflector 52 with a sensor (not shown).
Then, by controlling one or both of the irradiation time and the irradiation intensity of the recording laser beam LB1 for each portion where the lattice point at the interface of the polymer material layer 20 is to be formed, the size of the lattice point and the depth of the opening are controlled. Or the height of the convex portion can be adjusted.

Note that the irradiation time of the laser beam for forming one lattice point is preferably 120 μsec or less. By shortening the irradiation time to about 120 μsec or less, a diffractive optical element can be manufactured at high speed. For example, the diffractive optical element E having 250,000 lattice points can be manufactured in about 1 minute.

A method for manufacturing the diffractive optical element E using the manufacturing apparatus 50 as described above will be described.
First, the material EM before recording lattice points is placed on the stage 57. Then, the deflector 52 is operated, and the output of the recording laser 51 is modulated based on the exposure data stored in advance in synchronization with the operation of the deflector 52. The recording laser beam LB1 passes from the recording laser 51 through the PBS 54 and the quarter wavelength plate 55 to the deflector 52, is deflected by the deflector 52, and enters the imaging optical system 60. In the imaging optical system 60, the deflected recording laser beam LB1 passes through the first condenser lens 61, the second condenser lens 62, and the objective lens 63, and in the vicinity of the interface of the polymer material layer 20 of the material EM. The image is formed into fine dots. At this time, in the polymer material layer 20, a focal point is imaged at a position corresponding to the deflection angle. At this time, a part of the laser light reflected at the interface of the polymer material layer 20 returns in the order of the imaging optical system 60, the deflector 52, and the quarter wavelength plate 55, and the direction of polarization is rotated by 90 ° with respect to the direction. Then, the light is reflected by the PBS 54 and enters the light receiving element 53. The controller 59 adjusts the focus of the recording laser beam LB1 to a predetermined position by controlling the focus actuator 63A based on the signal received by the light receiving element 53.

In this manner, when the recording laser beam LB1 is condensed and irradiated near the interface of the polymer material layer 20 while scanning the polymer material layer 20 with the deflector 52, the dye absorbs the recording laser beam LB1. As a result, the temperature of the portion of the polymer material layer 20 irradiated with the recording laser beam LB1 is efficiently raised, and the interface is deformed. Specifically, an opening or a convex portion is formed by thermal expansion due to heating and rapid cooling after the irradiation of the recording laser beam LB1 is stopped. The height and width of the convex portion increase as the irradiation energy increases, and when the irradiation energy increases, an opening is formed by the high-temperature molten material moving from the center of the convex shape to the periphery during cooling. At this time, when the thickness of the polymer material layer 20 is thin, a hole penetrating the polymer material layer 20 is formed. Thus, an opening or a convex portion can be formed at the interface of the polymer material layer 20. By irradiating the recording laser beam LB1 with a pattern corresponding to the exposure data described above, dot-like lattice points constituting a diffractive optical element pattern can be formed at the interface of the polymer material layer 20. That is, a desired diffractive optical element pattern can be formed in a desired pattern area PA.

The diffractive optical element pattern can be calculated so as to obtain a laser intensity distribution that forms a desired reproduced image, for example, by a method disclosed in “Digital Diffractive Optics” Maruzen Publishing, 2005 or the like. For example, if an iterative Fourier transform algorithm (IFTA method) is used, a desired diffractive optical element pattern can be designed easily and at high speed by a computer. Divide the phase distribution of the designed diffraction grating surface into multiple pixels, quantize the amount of phase change required for each pixel, and record the laser light according to the size of the minute aperture and the size of the irregularities that are actually processed What is necessary is just to determine the irradiation energy of LB1. The simplest method of quantizing the phase change amount is to use a binary pattern of processed and unprocessed binary, and the phase difference between the processed pixel and the unprocessed pixel is half the wavelength used. It is desirable to be minutes. By making the quantization gradation a finer step, it is possible to suppress higher-order diffracted light and make the diffraction pattern closer to the design. Usually, it is desirable to divide into steps of 4 to 8 gradations, more preferably 16 to 32 gradations.

As described above, according to the manufacturing apparatus 50 and the manufacturing method of the present embodiment, since the diffractive optical element pattern is formed by deforming the interface of the polymer material layer 20, the diffractive optical can be easily performed without requiring development. Element E can be manufactured. Further, since the lattice point is formed by irradiating the polymer material layer 20 containing the dye with the recording laser light LB1 having a wavelength that is absorbed by the dye, the output of the recording laser light LB1 can be reduced, and the processing is performed at high speed. Can do. Furthermore, since the manufacturing method of this embodiment forms openings and / or protrusions by deforming the interface rather than peeling the material as in laser ablation, the diffractive optical element can be finely controlled in gradation. A pattern can be formed.

Further, in the manufacturing apparatus 50, since the imaging optical system 60 is an optical system including the objective lens 63 and the two

condenser lenses

61 and 62, a fine optical diffraction element pattern reduced with a simple configuration is formed. be able to.
Then, the control device 59 controls the objective lens 63 based on the output signal of the light receiving element 53 to adjust the focal position of the recording laser beam LB1 to a predetermined position. A high-performance diffractive optical element E can be obtained.

Furthermore, when the manufacturing apparatus 50 includes the transport stage 570, it is possible to continuously manufacture the plurality of diffractive optical elements E by moving the polymer material layer 20 by the transport stage 570.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be appropriately modified and implemented.

Next, an experiment in which lattice points are formed on the material of the diffractive optical element of the present invention will be described.
[Example 1]
Example 1 is an example in which a diffractive optical element pattern that displays a character image of “ABC” is composed of a binary binary pattern.

<Preparation of sample>
An azo metal complex dye compound A having the following structure and polymethyl methacrylate (Mw: 100,000 produced by Sigma-Aldrich) were dissolved in methyl ethyl ketone at a mass ratio of 45:55 to prepare a coating solution having a solid content concentration of 3% by mass.
Compound A was synthesized by the method described in JP 2010-100029 A.

This coating solution was applied by spin coating on a triacetyl cellulose film having a thickness of 100 μm serving as a support to form a polymer material layer.
The absorbance of this sample was measured with a spectrophotometer (UV-3100PC, manufactured by Shimadzu Corporation), and the light absorbance was calculated from the obtained absorbance (λ = 405 nm), and was confirmed to be 30%. The light absorption rate is
Light absorption [%] = (1-10 ^{− (absorbance)} ) × 100
Calculated with

<Diffraction grating formation>
The diffractive optical element pattern to be processed into the polymer material layer was designed by being divided into 250 × 250 pixel minute areas by the IFTA method, and a binary binary pattern of pixels to be processed and pixels not to be processed was used. FIG. 15A shows the original image, and FIG. 15B shows the diffractive optical element pattern for reproducing the image of FIG. 15A calculated by the IFTA method. FIG. 15C shows a simulation result obtained by reproducing the diffractive optical element pattern shown in FIG. The diffractive optical element pattern of FIG. 15B was processed into a 0.5 mm × 0.5 mm scanning area (pattern forming region) of the polymer material layer by the same manufacturing apparatus as in the above-described embodiment.

In the manufacturing apparatus, a biaxial galvanometer mirror was used as the deflector, and a 405 nm semiconductor laser was used as the recording laser beam. The laser intensity during processing was 2.8 mW on the surface of the polymer material layer. The polymer material layer is fixed on a stage movable in the optical axis direction of the recording laser beam and two orthogonal axes, and can be adjusted to an appropriate position for processing the diffractive optical element pattern.
As the objective lens, an infinity objective lens (magnification × 20) having an NA (numerical aperture) of 0.6 and a focal length of 10 mm is used, and the two condenser lenses constituting the 4f optical system are convex lenses having a focal length of 100 mm. It was used.
The irradiation time of the recording laser light per pixel was 50 μsec. The recording laser beam was raster scanned at a scanning rate of 20 Hz, and a 0.5 mm × 0.5 mm scanning area was processed in about 20 seconds in consideration of the transfer time of control data and the delay required for timing synchronization. The pitch of the lattice points was 2 μm.

When the processed polymer material layer was observed with a laser microscope (see FIG. 16 and FIG. 17) and an AFM (see cross-sectional profile in FIG. 18), a minute opening having a diameter of less than 1 μm was formed at the processed position. I confirmed.

As shown in FIG. 19, a 0.5-mm square pattern formation region was irradiated with a He—Ne laser having a wavelength of 633 nm so as to pass through the diffractive optical element as shown in FIG. The designed letters “ABC” are displayed by a diffraction pattern. That is, it was confirmed that a desired diffractive optical element was produced.

[Example 2]
Example 2 is an example in which a diffractive optical element pattern that displays a character image of “ABC” is composed of binary and ternary diffractive optical element patterns.

<Preparation of sample>
TINUVIN 326 (manufactured by BASF), which is a benzotriazole derivative, and polymethyl methacrylate (manufactured by Sigma-Aldrich Mw: 100,000) were dissolved in methyl ethyl ketone at a mass ratio of 15:85 to prepare a coating solution having a solid content concentration of 10% by mass.

This coating solution was spin-coated on a glass slide serving as a support to form a polymer material layer having a thickness of 1 μm.
The absorbance of this sample was measured with a spectrophotometer (UV-3100PC, manufactured by Shimadzu Corporation), and the light absorbance was calculated from the obtained absorbance (λ = 405 nm), and it was confirmed that it was 13%.

<Diffraction grating formation>
Then, as in Example 1, the diffractive optical element pattern to be processed into a polymer material is designed by dividing it into a minute area of 250 × 250 pixels by the IFTA method, and quantized with two types of binary and ternary values. The diffractive optical element pattern was calculated. In order to project the diffraction pattern by reflecting as shown in FIG. 3, the letters “ABC” in the original image were inverted. The polymer material layer was exposed using the same apparatus and conditions as in Example 1.
In the case of binary values, the recording exposure time of each pixel was set to 0 and 30 μsec, and in the case of ternary values, it was set to 0.14 μsec and 30 μsec.

In the case of binary values, the image shown in FIG. 20 is displayed on the screen, and in the case of ternary values, the image shown in FIG. 21 is displayed on the screen, and in each case, the pattern predicted by the simulation calculation is displayed. As shown in FIG. 21, in the case of ternary values, the inverted characters “ABC” in the first-order diffraction image could be suppressed.

[Example 3]
In Example 3, a two-photon absorption dye was used as a dye, and a diffractive optical element was manufactured using a pulse laser as a light source.

The polymer two-photon absorption compound B having the following structure was dissolved in methyl ethyl ketone to prepare a coating solution having a solid concentration of 9% by mass.

<Synthesis Method of Compound B> Compound B was synthesized by the following method. *

<Synthesis of Raw Material Compound 1> 27.0 g (250 mmol) of anisole and 42.9 g (200 mmol) of 4-bromobenzoyl chloride were dissolved in 500 ml of methylene chloride, cooled to an internal temperature of 5 ° C., and then divided into 6 portions. 33.4 g (250 mmol) was added and stirred under a nitrogen atmosphere for 8 hours. The reaction solution was poured into water, extracted with methylene chloride, and evaporated to dryness on a rotary evaporator to give white compound 2 quantitatively. The obtained compound 1 was confirmed to be the desired product by ¹ H NMR.

<Synthesis of Raw Material Compound 2> 140 ml of hydrobromic acid and 220 ml of acetic acid were added to 35.0 g (120 mmol) of raw material compound 1 and stirred at an internal temperature of 110 ° C. for 12 and a half hours. After allowing to cool to room temperature, the reaction solution was poured into water and stirred at room temperature for 20 minutes. The precipitate was filtered, washed with pure water, hexane: ethyl acetate = 5: 1, and dried under reduced pressure to obtain white compound 3 quantitatively. The obtained compound 2 was confirmed to be the desired product by ¹ H NMR.

<Synthesis of Raw Material Compound 3> 9.74 g (35.1 mmol) of raw material compound 2 was dissolved in 70 ml of tetrahydrofuran, 7.10 g (70.2 mmol) of triethylamine was added, and the internal temperature was cooled to 5 ° C. Thereafter, 3.67 g (35.1 mmol) of methacrylic acid chloride was added dropwise and stirred for 2 hours in a nitrogen atmosphere. The reaction solution was poured into water and stirred at room temperature for 20 minutes. The deposited precipitate was separated by filtration and dried at room temperature to obtain white compound 3 quantitatively. The obtained compound 3 was confirmed to be the target product by ¹ H NMR.

<Synthesis of Raw Material Compound 4> 63.5 g (214 mmol) of 5-bromo-2-iodotoluene, 44.7 g (235 mmol) of paratrifluoromethylphenylboronic acid, 2.40 g (10.7 mmol) of palladium acetate, sodium carbonate 68 To 1,0 g (642 mmol), 350 ml of 1,2-dimethoxyethane and 70 ml of water were added, and the mixture was stirred at an external temperature of 90 ° C. for 72 hours under a nitrogen atmosphere. The mixture was allowed to cool to room temperature, extracted with ethyl acetate, concentrated with a rotary evaporator, and purified with a silica gel column (hexane) to obtain 57.9 g (yield 86%) of white compound 4. The obtained compound 4 was confirmed to be the desired product by ¹ H NMR.

<Synthesis of Raw Material Compound 5> 57.9 g (184 mmol) of raw material compound 4, 56.1 g (221 mmol) of bispinacolatodiboron, [1,1′-bis (diphenylphosphino) ferrocene] palladium (II) dichloride dichloromethane 400 ml of dimethyl sulfoxide was added to 4.25 g (5.20 mmol) of the adduct and 54.2 g (552 mmol) of potassium acetate, and the mixture was stirred at an internal temperature of 90 ° C. for 5 hours in a nitrogen atmosphere. The mixture was allowed to cool to room temperature, extracted with ethyl acetate, concentrated with a rotary evaporator, and purified with a silica gel column (hexane: ethyl acetate = 10: 1) to obtain 57.5 g (yield 86%) of white compound 5. . The obtained compound 5 was confirmed to be the desired product by ¹ H NMR.

<Synthesis of Raw Material Compound 6> 14.8 g (42.9 mmol) of raw material compound 3, 18.6 g (51.5 mmol) of raw material compound 5, 2.48 g (2.15 mmol) of tetrakistriphenylphosphine palladium, 17 of potassium carbonate .8 g (129 mmol), 170 ml of toluene and 20 ml of water were added to 1 mg of dibutylhydroxytoluene, and the mixture was stirred at an external temperature of 90 ° C. for 12 hours in a nitrogen atmosphere. The mixture was allowed to cool to room temperature, extracted with ethyl acetate, concentrated on a rotary evaporator, purified with a silica gel column (ethyl acetate: hexane = 1: 5), recrystallized with ethyl acetate / hexane, filtered, dried and dried. 6.8 g (yield 32%) of compound 6 was obtained. The obtained compound 6 was confirmed to be the desired product by ¹ H NMR. ¹ H NMR (CDCl 3) 7.92 (d, 4H), 7.76 (dd, 2H), 7.71 (d, 2H), 7.59-7.55 (m, 2H), 7.50 ( d, 2H), 7.34 (d, 1H), 7.29 (dd, 2H), 6.41 (s, 1H), 5.82 (t, 1H), 2.37 (s, 3H)

<Synthesis of Compound B>
Tetrahydrofuran (5 g) was stirred at an external temperature of 70 ° C. in a nitrogen atmosphere. Thereto, 2.00 g (4.00 mmol) of raw material compound 6 dissolved in 26.7 g of tetrahydrofuran, 11.6 g (116 mmol) of methyl methacrylate, 29.8 mg of 2,2′-azobis (2,4-dimethylvaleronitrile). (0.12 mmol) was added dropwise over 2 hours, followed by stirring for 8 hours. The mixture was allowed to cool to room temperature, diluted with acetone, recrystallized from acetone / hexane, filtered and dried to obtain 4.77 g of compound D-1. The composition of the obtained polymer was confirmed by ¹ H NMR, and the molecular weight was measured by GPC. (Composition ratio raw material compound 6 / methyl methacrylate = 12/88 (molar ratio), Mw = 367,000)

<Formation of polymer material layer>
The obtained coating solution was spin-coated on a glass slide serving as a support to form a polymer material layer having a thickness of 1 μm.
The absorbance of this sample was measured with a spectrophotometer (UV-3100PC, manufactured by Shimadzu Corp.), and the light absorbance was calculated from the obtained absorbance (λ = 405 nm), and it was confirmed to be 0%.

<Diffraction grating formation>
As a recording laser, a pulse laser having a wavelength of 405 nm, a pulse width of 2.0 ps, and a repetition rate of 76 MHz was used. For controlling the laser irradiation energy, the pulse intensity was controlled using an electro-optic modulator (EOM) in the optical path. As the objective lens, an infinite objective lens having a NA of 0.85 (magnification × 60) was used. The pulse laser was set so that the peak power on the surface of the polymer material layer was 60 W, and the number of irradiation pulses was controlled by EOM so that dots with an interval of 300 nm were formed. When the surface of the polymer material layer after processing was observed with AFM, it was confirmed that protrusions having a height of about 30 to 40 nm were formed as shown in the AFM image of FIG. 22 and the cross-sectional profile of FIG. It was confirmed that minute phase modulation pixels could be processed.

Claims

A diffractive optical element having a polymer material layer,
The polymer material layer has a polymer material and a dye dispersed in the polymer material layer or covalently bonded to the polymer material in the polymer material layer,
A diffractive optical element, wherein a diffractive optical element pattern having dot-like openings and / or convex portions is arranged on an interface of the polymer material layer.
The diffractive optical element according to claim 1, wherein the dye contains a one-photon absorption dye.
2. The diffractive optical element according to claim 1, wherein the dye includes a multiphoton absorbing dye.
The diffractive optical element according to claim 1, further comprising a support that supports the polymer material layer.
2. The diffractive optical element according to claim 1, further comprising a cover layer on a side where the opening and / or the convex portion are arranged in the polymer material layer.
The opening and / or the convex portion has a plurality of types having different depths or heights, and a multivalued diffractive optical element pattern is formed by the plurality of types of openings and / or convex portions. The diffractive optical element according to claim 1.
2. The diffractive optical element according to claim 1, wherein the dye has an absorption wavelength band mainly of 450 nm or less, and a light transmittance of a wavelength of 450 to 800 nm is 50% or more.
Preparing a polymer material layer having a polymer material in which a pigment is dispersed or a polymer material in which a pigment is covalently bonded;
A laser beam having a wavelength that is absorbed by the dye is irradiated near the interface of the polymer material layer to deform the interface, and this irradiation is performed in a predetermined pattern at the interface to form a diffractive optical element pattern at the interface. A method for manufacturing a diffractive optical element, comprising forming a dot-like opening and / or a convex portion.
9. The method of manufacturing a diffractive optical element according to claim 8, wherein an irradiation time of laser light for forming one of the openings or the convex portions is 120 μsec or less.
9. The diffraction according to claim 8, wherein reflected light from the interface is detected by a sensor during laser light irradiation, and a focal position of the laser light is adjusted to a predetermined position based on an output signal of the sensor. A method for manufacturing an optical element.
A diffractive optical element manufacturing apparatus for forming a diffractive optical element pattern in a polymer material layer having a polymer material in which a dye is dispersed or a polymer material in which a dye is covalently bonded,
A light source that emits laser light having a wavelength that the dye absorbs;
A deflector for deflecting the laser light emitted from the light source;
An imaging optical system for imaging the laser beam deflected by the deflector in the vicinity of the interface of the polymer material layer;
A controller for controlling the output of the light source and the deflector,
The control device controls the deflector to form an interface of the polymer material layer so as to form a dot-shaped opening and / or a convex portion constituting a diffractive optical element pattern at the interface of the polymer material layer. An apparatus for manufacturing a diffractive optical element, wherein the output of the light source is changed in synchronization with scanning with laser light.
The diffractive optical element manufacturing apparatus according to claim 11, wherein the imaging optical system includes an objective lens and at least two condenser lenses.
12. The apparatus for manufacturing a diffractive optical element according to claim 11, wherein the irradiation time of the laser beam for forming the one opening or the convex portion is 120 μsec or less.
12. The diffractive optical element manufacturing apparatus according to claim 11, wherein the imaging optical system includes an objective lens, and the objective lens has a numerical aperture of 0.13 or more.
A sensor for detecting laser light reflected by the interface;
12. The diffraction according to claim 11, wherein the control device is configured to control the imaging optical system based on an output signal of the sensor to adjust a focal position of laser light to a predetermined position. Optical element manufacturing equipment.
The apparatus for producing a diffractive optical element according to claim 11, wherein the wavelength of the laser beam emitted from the light source is 450 nm or less.
12. The apparatus for manufacturing a diffractive optical element according to claim 11, further comprising a transport device that moves the polymer material layer with respect to the laser beam.