JP6303923B2 - Diffractive optical element - Google Patents

Description

  The present invention has a characteristic of high refractive index and low dispersion, and a resin precursor composition suitable for use in a multilayer diffractive optical element, an optical element using this resin precursor composition, The present invention relates to an optical element and a diffractive optical element obtained by a combination of an optical material and a resin having a characteristic of low refractive index and high dispersion.

Attempts to incorporate a diffractive optical element into an optical system have been made for a long time, but in particular, a diffractive optical element in which the height of a grating is processed to one wavelength, that is, a phase difference equivalent to 2π, concentrates light on the first-order diffracted light. Therefore, there have been considered applications aimed at correcting the chromatic aberration of the optical system and reducing the size and weight.
However, in the case of a single-layer diffractive optical element whose grating surface is in contact with the air, the first-order diffraction efficiency can be made 100% at the reference wavelength, but the diffracted light of other orders increases as the wavelength goes away from the reference wavelength, which is the flare light. Therefore, there is a problem that the optical performance is deteriorated.
In order to solve this problem, a contact multilayer diffractive optical element having a structure in which two gratings made of two characteristic types of resin are in close contact has been devised (for example, References 1 and 2). That is,
(N2-n1) × h = λ (1)
In formula (1), n1 and n2 are the refractive indexes of the resin (n2> n1), h is the grating height of the diffractive optical element, and λ is the wavelength.
If Expression (1) always holds in the used wavelength range, the diffraction efficiency of the primary light becomes 100% in the entire used wavelength range, and flare caused by the diffracted light can be eliminated.

JP 2003-262713 A

Kensaburo Suzuki: "Introduction to the revised revised diffractive optical element", 163 (Opttronics, 1997)

  According to Formula (1), it turns out that the refractive index difference (n2-n1) of resin and a wavelength have a proportional relationship. In order for the difference in refractive index between the two resins to increase as the wavelength increases, the first resin (refractive index n1) has a low refractive index and high dispersion resin, and the second resin (refractive index n2) has a high refractive index. It is necessary to be composed of a low dispersion resin. In other words, a combination of resins in which the difference between the dispersion values of the two resins (Abbe number or average dispersion (nF-nC)) becomes large is necessary. Moreover, since the grating height h can be lowered as the refractive index difference (n2-n1) between the two resins is larger, the processing of the grating becomes easier.

  However, general resins have a tendency that the dispersion value increases as the refractive index increases, and the dispersion value decreases as the refractive index decreases. For this reason, it is not easy to combine high refractive index low dispersion and low refractive index high dispersion resin and to increase the refractive index difference, and to produce a close contact multilayer diffractive optical element with excellent optical performance In order to do so, it has been necessary to develop new resins.

  Furthermore, the contact multilayered diffractive optical element has conditions that must be satisfied according to its application. For example, in order to apply a contact multilayer diffractive optical element to an optical system that performs observation or measurement using fluorescence, such as a biological microscope, in addition to the above-described refractive index dispersion conditions, the excitation wavelength of fluorescence (usually ultraviolet light) In addition, it is necessary to suppress the generation of autofluorescence from the contact multilayer diffractive optical element itself to an extremely small amount. In order to apply a contact multilayer diffractive optical element to an interchangeable lens for a camera, even if the direction of light incident on the diffractive optical element changes, the change in flare caused by the diffracted light can be suppressed to an allowable level or less. It is considered important.

  In view of such circumstances, the present invention obtains a resin having a higher refractive index and a lower dispersion than that of a conventional resin and a resin precursor composition thereof, and an optical element using the resin, and further uses thereof. In order to satisfy the conditions according to the above, an object is to obtain a close-contact multilayer diffractive optical element by a combination of this resin and a low-refractive index high-dispersion resin.

In order to achieve such an object, the resin precursor composition for an optical material according to the present invention includes an addition reaction product of a composition containing a thiol (component A) represented by the following chemical formula 1 and (meth) acrylate. .

  In the resin precursor composition for an optical material according to the present invention, the addition reaction product is a thiol (component A) represented by the above chemical formula 1 and (meth) acrylate in a range of 1: 2 to 1:10. It is obtained by subjecting a composition containing the above in a molar ratio to an addition reaction.

More preferably, the above-mentioned addition reaction product contains a thiol (component A) represented by the above chemical formula 1 and (meth) acrylate in a molar ratio in the range of 1: 2 to 1: 3.5. Obtained by addition reaction.

In the resin precursor composition for an optical material according to the present invention, preferably, the (meth) acrylate is an acrylate (B component) represented by the following chemical formula 2.

In the resin precursor composition for an optical material according to the present invention, preferably, the above-described addition reaction product is a thiol (component A) represented by the following chemical formula 1, a (meth) acrylate, and a thiol represented by the following chemical formula 3 ( It is obtained by subjecting a composition containing C component) to an addition reaction.

  Another optical element according to the present invention is obtained by curing the resin precursor composition for optical materials described above.

A diffractive optical element according to the present invention includes a diffraction grating in which the above-described optical element and an optical element having a lower refractive index and higher dispersion than the optical element are stacked and a diffraction grating is provided at the interface.

The diffractive optical element according to the present invention is obtained by curing a resin precursor composition in which the optical element having a low refractive index and high dispersion contains bisphenol AF ethylene oxide-modified di (meth) acrylate represented by the following chemical formula 4. .

In the optical element according to the present invention including the diffractive optical element, the low refractive index and high dispersion optical element includes bisphenol A ethylene oxide-modified di (meth) acrylate represented by the following chemical formula 5 and the following chemical formula 6: It is obtained by curing a resin precursor composition containing a fluorinated di (meth) acrylate represented by:

  The above-described resin precursor composition according to the present invention is a material having a high refractive index and low dispersion, and is suitable for use in a contact multilayer diffractive optical element. The optical element according to the present invention has a high refractive index and low dispersion. The resin is composed of a combination of a resin having a low refractive index and a high dispersion.

It is a graph which shows the refractive index (nd) and dispersion | distribution (nF-nC) of high refractive index low dispersion resin which concern on this embodiment. It is a graph which shows the fluorescence measurement result after a light resistance test about resin of the high refractive index low dispersion | distribution which concerns on the said this embodiment. It is a graph which shows the light-transmittance measurement result after a light resistance test about the high refractive index low dispersion resin which concerns on the said embodiment. It is sectional drawing which shows the structure of the contact | glue multilayer type | mold diffractive optical element comprised using the high refractive index low dispersion resin which concerns on the said embodiment. It is sectional drawing of the lens comprised including the contact | adherence multilayer type | mold diffractive optical element comprised using the resin of the high refractive index low dispersion | distribution which concerns on the said embodiment. It is a graph which shows the diffraction efficiency of the contact | adherence type | mold diffractive optical element comprised using the high refractive index low dispersion resin and low refractive index high dispersion resin which concern on the said this embodiment.

  First, a high refractive index and low dispersion resin precursor will be described as a preferred embodiment of the present application. This resin precursor contains an addition reaction product of a composition containing a thiol represented by the following chemical formula 1 and (meth) acrylate.

化学式１のチオールは、「トリシクロデカンジメタンチオール（tricyclodecanedimethanethiol）」で、通称ＴＤＤＴである。トリシクロデカンジメタンチオール（ＴＤＤＴ）は低分散特性を示すトリシクロデカン骨格を備えるとともに、高屈折率特性を示す硫黄元素を有する。

The thiol of Formula 1 is “tricyclodecanedimethanethiol”, commonly known as TDDT. Tricyclodecane dimethanethiol (TDDT) has a tricyclodecane skeleton exhibiting low dispersion characteristics and has a sulfur element exhibiting high refractive index characteristics.

  The thiol represented by the chemical formula 1 is a liquid at normal temperature, and an optical element cannot be formed as it is. Therefore, first, an acrylate having a tricyclodecane structure represented by the following chemical formula 2 was added to the thiol (TDDT) at a predetermined composition ratio (molar ratio) to be oligomerized. The addition reaction may be an enethiol reaction, a Michael addition reaction, or the like. However, the enthiol reaction has a drawback that the reaction between acrylic and thiol cannot be controlled, and cannot be stopped by an oligomer. On the other hand, since the reaction of Michael addition stops with an oligomer, there is an advantage that curing shrinkage during subsequent ultraviolet irradiation is small. This time, Michael addition reaction was used.

化学式２のアクリレートＢは、正式名称が「トリシクロデカンジメタノールジ（メタ）アクリレート（tricyclodecanedimethanoldi(meth)acrylate）」で、通称ＴＣＤＡである。

Acrylate B of Chemical Formula 2 has the official name “tricyclodecanedimethanoldi (meth) acrylate” and is commonly known as TCDA.

  Since thiol has high refractive index characteristics derived from sulfur element and low dispersibility derived from tricyclodecane skeleton, addition of (meth) acrylate monomer to this causes a precursor of resin that exhibits high refractive index and low dispersion characteristics. A body composition is obtained. Here, in consideration of the balance between the high refractive index characteristics and the low dispersion characteristics, a (meth) acrylate monomer having low dispersion characteristics is selected as the (meth) acrylate. As an index of (meth) acrylate having dispersion value characteristics, it is preferable that the Abbe number νd of a resin obtained by curing a (meth) acrylate simple substance is 51 or more, and the refractive index nd is 1.52 or more.

  For example, there are a norbornene structure, a cyclohexane structure, an adamantane structure, a tricyclodecane structure, etc. as structures having low dispersibility, and (meth) acrylates having these structures can be used. Among them, (meth) acrylate having a tricyclodecane structure as represented by the above chemical formula 2 is particularly preferable.

  A light (or heat) polymerization initiator was added to the oligomerized resin precursor composition, and this was cured by irradiation with ultraviolet light (or application of heat). In this way, in the process of curing by irradiation with ultraviolet light (or heat), or by molding or processing this into a desired shape after curing, an optical element used for a lens, a diffractive optical element or the like is produced.

  In order to obtain a resin precursor composition having high refractive index and low dispersion characteristics and suitable for use in a multilayer diffractive optical element, the low refractive index of the thiol represented by the above chemical formula 1 is low. The blending ratio of (meth) acrylate showing dispersibility is an important factor. In the present invention, considering the balance between high refractive index and low dispersibility, the blending ratio (molar ratio) of the thiol represented by the above chemical formula 1 and the (meth) acrylate having a low dispersion structure is 1: 2 to 2. A range of 1:10 is preferred. When the blending ratio of the (meth) acrylate is below the lower limit, the dispersion value of the resin obtained by curing the resin precursor composition increases, and the high refractive index and low dispersion characteristics suitable for use in the diffractive optical element are not exhibited. .

The upper limit of the blending ratio of (meth) acrylate is, for example, a compound having three or more sulfur elements in one molecule (for example, the following chemical formula 3), in addition to the thiol represented by the chemical formula 1 showing high refractive index properties, It is a value that takes into account the addition of another substance exhibiting a high refractive index. If this upper limit is exceeded, the balance between the high refractive index and low dispersibility of the resin obtained by curing the resin precursor composition is broken, making it unsuitable for use in a multilayer diffractive optical element.
In consideration of the balance between the high refractive index of thiol represented by Chemical Formula 1 and the low dispersibility of (meth) acrylate, the molar ratio of thiol to (meth) acrylate is 1: 2 to 1: 3. More preferably, it is 5.

About the said composition, the following 3 types (Examples 1-3) were produced.
Example 1: Composition ratio TCDA: TDDT = 2.5: 1
Example 2: Composition ratio TCDA: TDDT = 3: 1
Example 3: Composition ratio TCDA: TDDT = 3.5: 1
In Examples 1 to 3, TDDT having a structural formula of m = 1 and n = 1 in the above chemical formula 1 is used as the thiol. Further, TCDA having a structure of R = H, m = 1, n = 1 is used as (meth) acrylate.

  Separately from the mixed composition, the thiol represented by the following chemical formula 3 and the acrylate as a low dispersion component were oligomerized by Michael addition reaction to the thiol at a predetermined composition ratio (molar ratio).

化学式３のチオールは、「２，５−ジメルカプトメトル−１，４−ジチアン（2,5-dimercaptomethyl-1,4-dithiane）」で、通称ＤＭＭＤであり、常温で液体の化合物である。

The thiol of Formula 3 is “2,5-dimercaptomethyl-1,4-dithiane”, commonly called DMMD, and is a liquid compound at room temperature.

The thiol of Formula 1, TCDA of Formula 2, and DMMD of Formula 3 were oligomerized at the following composition ratio. In Example 4, TDDT having a structural formula of m = 1 and n = 1 is used as the thiol of Chemical Formula 1. Further, TCDA having a structure of R = H, m = 1, n = 1 is used as the (meth) acrylate of the above chemical formula 2.
Example 4: Composition ratio TCDA: DMMD: TDDT = 22: 5: 3
By adding a thiol containing a large amount of elemental sulfur as represented by Chemical Formula 3, an even higher refractive index can be achieved. By increasing the refractive index of the resin, the lattice height can be reduced, that is, molding becomes easy.

First, 0.1% by weight of Irgacure 184 (manufactured by BASF Japan Ltd.), which is a photopolymerization initiator, was added to each of the Michael addition reactants of Examples 1 to 4 to prepare a resin precursor composition F. This resin precursor composition F was put between two quartz substrates subjected to silane coupling treatment, and ultraviolet light was irradiated in this state to produce a cured resin product G (referred to as resin G). At this time, the interval between the two quartz substrates was adjusted and set so that the thickness of the resin precursor composition G would be 100 μm. Moreover, ultraviolet light irradiation was performed using the ultraviolet light irradiation machine (made by Ubix Corporation) provided with LED which generate | occur | produces 365 nm ultraviolet light. At this time, the ground glass over performs irradiation at 25 mW / cm ² 60 seconds as the temporary curing, and then subjected to irradiation of 250 seconds at 40 mW / cm ² as a main curing. If the light source includes 365 nm, a metal halide lamp, a high-pressure mercury lamp, and an LED can be used. In particular, when self-fluorescence is desired to be suppressed, an LED is desirable. Therefore, in this embodiment, an LED is used.

Using the ultraviolet light irradiator (manufactured by Ubix Co., Ltd.) equipped with the LED that generates ultraviolet light of 365 nm, the resin having a thickness of 100 μm thus produced is irradiated with ultraviolet light for a long time. Light resistance was tested. The ultraviolet light illuminance at this time was 350 mW / cm ² , and irradiation was performed for 216 minutes, and fluorescence measurement and transmittance measurement were performed after this irradiation. The transmittance was measured with U-3900H manufactured by Hitachi High-Technologies Corporation. The amount of fluorescence was measured by F-7000 manufactured by Hitachi High-Technologies Corporation.

  The refractive index and dispersion value of the resins prepared with the compositions of Examples 1 to 4 are shown in FIG. FIG. 1 shows that a resin obtained by curing a resin precursor containing TDDT and (meth) acrylate has a high refractive index and low dispersion.

Next, one of the resins prepared with the compositions of Examples 1 to 4 was subjected to a light resistance test by irradiation with ultraviolet light for a long time to measure fluorescence and transmittance. The results are shown in FIG. 2 and FIG. This light resistance test was performed using an ultraviolet light irradiator (manufactured by Ubix Corporation) equipped with an LED that generates ultraviolet light of 365 nm. The ultraviolet light illuminance at this time was 350 mW / cm ² , and irradiation was performed for 216 minutes, and fluorescence measurement and transmittance measurement were performed after this irradiation. The transmittance was measured with U-3900H manufactured by Hitachi High-Technologies Corporation. The amount of fluorescence was measured by F-7000 manufactured by Hitachi High-Technologies Corporation. FIG. 2 shows the fluorescence characteristics after ultraviolet irradiation of the resins of Examples 1 and 4 and the fluorescence characteristics after ultraviolet irradiation of the adhesive used in the microscope objective lens for comparison. In the figure, the horizontal axis represents the wavelength of light, and the vertical axis represents the fluorescence intensity in arbitrary units [arb.unit]. From the figure, it can be seen that the fluorescence intensity of the resin of the present invention is very small after ultraviolet irradiation.

  FIG. 3 shows the transmittance characteristics of Examples 1 to 4 and the transmittance characteristics of the adhesive used for the microscope objective lens for comparison. As shown in FIG. 3, the resins of Examples 1 to 4 have high ultraviolet light transmittance (90% or more at 365 nm), have good transmission performance from the ultraviolet region to the visible region, and are organisms that perform fluorescence observation. It can be seen that the system can sufficiently withstand the use of a microscope objective lens.

  Furthermore, it was found that the resins prepared with the compositions of Examples 1 to 4 did not show yellowing after the light resistance test, and also have light resistance in this respect.

  The type and addition amount of the polymerization initiator used for making the resin precursor composition and making it effective by irradiation with ultraviolet light can be appropriately selected. The addition amount can be selected within the range of 0.05 to 3 wt%, and preferably selected within the range of 0.07 to 0.7 wt%. Suitable polymerization initiators for the precursor composition include, for example, benzophenone, hydroxybenzophenone methanesulfonate, o-benzoylmethyl benzoate, p-chlorobenzophenone, p-dimethylaminobenzophenone, benzoin, benzoin allyl ether, benzoin methyl ether. , Benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether, acetophenone, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, benzyl dimethyl ketal, 2-hydroxy-2-methylpropiophenone, 1- (4-isopropylphenyl)- Photopolymerization initiators such as 2-hydroxy-2-methylpropiophenone, 1-phenyl-1,2-propanedione-2-o-benzoyloxime, Thermal polymerization initiators such as azo compounds (azobisisobutyronitrile, dimethyl-2, 2′-azobisisobutyrate, etc.), peroxides (benzoyl peroxide, di (t-butyl) peroxide, etc.) can be mentioned. .

  FIG. 4 shows the structure (cross-sectional shape) of a multi-contact diffractive optical element. The diffractive optical element includes a first diffractive optical element 1 made of a resin having a high refractive index and low dispersion, and a second diffractive optical element 2 made of a resin having a low refractive index and high dispersion, and the first and second diffractive optical elements. A serrated relief pattern 5 (diffraction grating pattern) is formed between the elements 1 and 2. The resin precursor composition reactants of Examples 1 to 4 described above are high refractive index and low dispersion resins, and are used as the resin of the first diffractive optical element 1.

The resin used for the low refractive index and high dispersion second diffractive optical element 2 which is the other of the above-mentioned contact multilayer optical element will be described below.
A plurality of types of resin compositions can be used as the low refractive index and high dispersion resin constituting the second diffractive optical element 2. For example, bisphenol AF ethylene oxide modified di (meth) acrylate represented by the following chemical formula 4 is used as the resin. It is preferable to use it as a precursor composition.

The general name represented by the chemical formula 4 is called bisphenol AF ethylene oxide-modified di (meth) acrylate, and is a resin precursor that is liquid at room temperature.
Furthermore, in the above chemical formula 4, R = H, m = 1, and n = 1 2,2-bis (4- (2-acryloyloxy) ethoxy) phenyl-1,1,1,3,3,3- Hexafluoropropane or 2,2-bis (4- (2-methacryloyloxy) ethoxy) phenyl-1,1,1,3,3,3-hexa in which R = CH ₃ , m = 1, and n = 1 It is preferable to use fluoropropane as the resin precursor composition.

  Alternatively, 70:30 (w / w) of bisphenol A ethylene oxide-modified di (meth) acrylate represented by the following chemical formula 5 and a fluorinated di (meth) acrylate represented by the following chemical formula 6 which is a fluorine monomer A mixture of the above may be used as the resin precursor composition.

Furthermore, bisphenol A ethylene oxide-modified di (meth) acrylate in which R = CH ₃ and m + n = 2.3 in the above chemical formula 5 and a compound in which R = H and m = 4 in the following chemical formula 6 are 70:30 ( It is preferable to use a w / w) mixture or the like.

  Next, specific manufacturing methods and characteristics of the multi-contact diffractive optical element of the present invention will be described in Examples 5 and 6 below.

(Example 5)
In this embodiment, in the diffractive optical element shown in FIG. 4, a resin obtained by photocuring the resin precursor composition having the blending ratio of Example 1 which is the above-described high refractive index and low dispersion resin as the first diffractive optical element 1. And the resin precursor 2,2-bis (4- (2-acryloyloxy) ethoxy) phenyl-1,1, as the second diffractive optical element 2 with a low refractive index and high dispersion described above as the second diffractive optical element 2 A resin obtained by photocuring 1,3,3,3-hexafluoropropane (R = H, m = 1, n = 1 in the above chemical formula 4) was used.

First, as a low refractive index high dispersion resin, 2,2-bis (4- (2-acryloyloxy) ethoxy) phenyl-1,1,1,3,3,3-hexafluoropropane is a photopolymerization initiator. A resin precursor composition was prepared by adding 0.1 wt% of Irgacure 184 (manufactured by BASF Japan Ltd.). After applying this to a predetermined mold for forming the diffractive optical element, it is pressed with a substrate and irradiated with ultraviolet rays. The ultraviolet light irradiation was performed using an ultraviolet light irradiation machine (manufactured by Ubix Co., Ltd.) equipped with an LED that generates ultraviolet light of 365 nm. At this time, irradiation for 60 seconds was performed at 25 mW / cm ² as temporary curing through the ground glass.
If the light source includes 365 nm, a metal halide lamp, a high-pressure mercury lamp, an LED, or the like can be used. In particular, when self-fluorescence is desired to be suppressed, an LED is desirable. Therefore, in this embodiment, an LED is used. After temporary curing, the diffractive optical element 2 is completed by removing it from the mold.

Next, a composition (molar ratio TCDA) of the thiol (m = n = 1) represented by the chemical formula 1 and the acrylate (R = H, m = 1, n = 1) represented by the chemical formula 2 A resin precursor composition was prepared by adding 0.1 wt% of Irgacure 184 (manufactured by BASF Japan Ltd.) as a photopolymerization initiator to the Michael addition reaction product of TDDT = 2.5: 1). This is applied onto the molded diffractive optical element 2, and the substrate is pressed and irradiated with ultraviolet rays.
The ultraviolet light irradiation was performed using an ultraviolet light irradiation machine (manufactured by Ubix Co., Ltd.) equipped with an LED that generates ultraviolet light of 365 nm. At this time, the ground glass over performs irradiation at 25 mW / cm ² 60 seconds as the temporary curing, and then subjected to irradiation of 250 seconds at 40 mW / cm ² as a main curing.

(Example 6)
Photopolymerization started on the Michael addition reaction product of Example 2 (molar ratio TCDA: TDDT = 3: 1), which is the high refractive index low dispersion resin described above as the first diffractive optical element 1 as the high refractive index low dispersion diffractive optical element The diffractive optical element 1 was molded in the same manner as in Example 5 with respect to the resin precursor composition to which 0.1 wt% of Irgacure 184 (manufactured by BASF Japan Ltd.) as an agent was added. In this example, 2,2-bis (4- (2- (meth) acryloyloxy) ethoxy) phenyl-1,1,1,3,3,3-hexafluoropropane (low refractive index and low dispersion optical element ( The diffractive optical element 1 was molded in the same manner as in Example 5 using a resin precursor composition in which 0.1 wt% of Irgacure 184 (manufactured by BASF Japan Ltd.) was added to (BMHF).

Example 5:
(High refractive index low dispersion optical element) TCDA: TDDT = 2.5: 1 addition reaction product, Irgacure 184 0.1 wt%
(Low refractive index and high dispersion optical element) 2,2-bis (4- (2-acryloyloxy) ethoxy) phenyl-1,1,1,3,3,3-hexafluoropropane, Irgacure 184 0.1 wt%

Example 6:
(High refractive index and low dispersion optical element) TCDA: TDDT = 3: 1 addition reaction product, Irgacure 184 0.1 wt%
(Low Refractive Index High Dispersion Optical Element) 2,2-bis (4- (2- (meth) acryloyloxy) ethoxy) phenyl-1,1,1,3,3,3-hexafluoropropane, Irgacure 184 0 .1wt%

  Table 1 shows the grating height of the serrated relief pattern 5 (diffraction grating pattern) formed between the first and second diffractive optical elements 1 and 2 in FIGS. As shown in Table 1, in Example 5, the height of the serrated relief pattern 5 formed between the first and second diffractive optical elements 1 and 2 is 25.6 μm, and in Example 6, it is 25. It was possible to set it to 5 μm.

このように、レリーフパターン５の格子高さはどちらの実施例においても非常に小さい値に抑えることができた。

As described above, the grating height of the relief pattern 5 was able to be suppressed to a very small value in both examples.

FIG. 6 shows the diffracted light intensity of the unnecessary diffraction orders in the optical lens 10 having this configuration.
The vertical axis represents (0th-order light diffracted light intensity + second-order light diffracted light intensity) / first-order light diffracted light intensity, and the smaller this value, the better the diffraction performance. The diffractive optical element formed in the embodiment of the present application has a lower diffracted light intensity of the unnecessary order than the case where a diffractive optical element made of a conventional resin is used, and exhibits high diffraction performance. Further, it has a high diffraction efficiency for obliquely incident light, and can be used for a wide range of applications such as biological microscope objective lenses, interchangeable lenses, binoculars, telescopes, security cameras, and projectors.

  FIG. 5 shows an example of the diffractive optical element 10 using the optical element of the present application. A so-called multi-layered diffractive optical element composed of a diffraction grating in which a high-refractive index low-dispersion resin 11 of the present invention and a low-refractive index high-dispersion resin 12 are laminated and a diffraction grating 13 is provided at the interface. Element 10. The contact multilayer type diffractive optical element 10 may be formed on one substrate 15 (or lens) as shown in FIGS. 5A to 5B, and FIGS. As shown in FIG. 4B, a configuration in which the substrate is sandwiched between two substrates 15 (or lenses) may be used. Either high refractive index low dispersion resin or low refractive index high dispersion resin may be formed in the first layer.

  The substrate 15 may be a parallel plate, and may have a plano-concave shape, a plano-convex shape, a meniscus shape, or a biconvex shape. The contact multilayer optical element may be formed on a flat surface, or may be formed on a convex surface or a concave surface. The optical elements and optical elements of the present invention are widely used in photographing optical systems, optical systems for microscopes, optical systems for observation optical systems, and the like, and an optimal configuration can be selected as appropriate depending on the application and form of the optical system.

  The high refractive index and low dispersion resin G according to the present invention has been described above as an example. However, the high refractive index and low dispersion optical material used in the present invention is not limited to the resin G. The resin made of the resin precursor composition containing the thiol represented by the above-described chemical formula 1 and (meth) acrylate has similar characteristics.

DOE diffractive optical element 1 first optical element 2 second optical element 5 relief pattern (diffraction grating pattern)
DESCRIPTION OF SYMBOLS 10 Diffractive optical element 11 High refractive index low dispersion resin 12 Low refractive index high dispersion resin 13 Diffraction grating 15 Substrate (or lens)

Claims (6)

A first optical element formed by curing a resin precursor composition for an optical material containing an addition reaction product of a composition containing a thiol represented by the following chemical formula 1 and (meth) acrylate ;
A second optical element formed by curing a resin precursor composition containing bisphenol AF ethylene oxide-modified di (meth) acrylate represented by the following chemical formula 4:
A diffraction grating provided at an interface between the first optical element and the second optical element;
A diffractive optical element.

A first optical element formed by curing a resin precursor composition for an optical material containing an addition reaction product of a composition containing a thiol represented by the following chemical formula 1 and (meth) acrylate;
A second optical material obtained by curing a resin precursor composition containing bisphenol A ethylene oxide-modified di (meth) acrylate represented by the following chemical formula 5 and a fluorinated di (meth) acrylate represented by the following chemical formula 6. Elements and
A diffraction grating provided at an interface between the first optical element and the second optical element;
A diffractive optical element.

2. The addition reaction product is obtained by addition reaction of a composition containing the thiol represented by Formula 1 and the (meth) acrylate in a molar ratio within a range of 1: 2 to 1:10. Or the diffractive optical element according to 2 ; The addition reaction product is obtained by addition reaction of a composition containing the thiol represented by Formula 1 and the (meth) acrylate at a molar ratio in the range of 1: 2 to 1: 3.5. Item 3. The diffractive optical element according to Item 1 or 2 . The (meth) acrylate is a diffractive optical element according to any one of claims 1 to 4, which is a tricyclodecane dimethanol di (meth) acrylate represented by the following chemical formula 2.

The addition reaction product is an addition reaction of a composition containing the thiol represented by Formula 1 and (meth) acrylate and the thiol “2,5-dimercaptomethyl-1,4-dithiane” represented by Formula 3 below. the diffractive optical element according to any one of claims 1 to 5, obtained Te.

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