JP2011094080A - Polymerizable compound, photocurable composition, optical element and optical head device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymerizable compound capable of satisfying both high refraction index and high light resistance; a photocurable composition including the compound; an optical element, such as a wavelength-selective diffraction element 1A etc., with favorable light resistance to blue laser; and an optical head device using the optical element. <P>SOLUTION: The polymerizable compound is represented by GeA<SP>1</SP>A<SP>2</SP>A<SP>3</SP>A<SP>4</SP>in which germanium and four cyclic groups are directly bonded (wherein each of A<SP>1</SP>, A<SP>2</SP>, A<SP>3</SP>and A<SP>4</SP>is preferably a phenyl group; each of 0 to 3 hydrogen atoms of the phenyl group may be substituted by a polymerizable part represented by CH<SB>2</SB>=CR-COO-Y-; one part or total part of remaining hydrogen atoms of the cyclic groups may be substituted by methyl groups or fluorine atoms; and any one of cyclic groups A<SP>1</SP>, A<SP>2</SP>, A<SP>3</SP>and A<SP>4</SP>may be substituted by the polymerizable part represented by CH<SB>2</SB>=CR-COO-Y-). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polymerizable compound, a photocurable composition, an optical element, and an optical head device.

  Optical resin materials are widely used for applications such as optical films, lenses, optical disks, and optical elements for optical pickups. In recent years, improvement in light resistance has been demanded due to increase in illuminance and shortening of the wavelength used, and if light resistance is insufficient, the transmittance and optical distortion will increase, and the parts will be stable for a long time There is a problem that the device cannot be used.

  In particular, in order to increase the capacity of an optical disk, the wavelength is changed from a DVD (Digital Versatile Disc) method to a BD (Blu-ray Disc) method using a blue semiconductor laser having a shorter wavelength (hereinafter also referred to as a blue LD) as a light source. Since it is close to the ultraviolet region at around 405 nm, a resin material having excellent light resistance is required for the optical element for optical pickup. Patent Document 1 proposes a wavelength-selective diffraction element in which materials having different refractive indexes and wavelength dispersion are combined, but does not specifically describe a resin material for blue LD applications. In controlling the refractive index and wavelength dispersion, aromatics such as phenyl groups are useful. When increasing the refractive index, the number of phenyl groups may be increased, but the light resistance tends to deteriorate. In addition, when priority is given to light resistance, it is better that the number of phenyl groups is smaller, and there is a problem that the refractive index cannot be increased.

  Examples of conventional high refractive index resin materials include compounds having a skeleton such as fluorene, tetraphenylmethane, 1,1,2,2-tetraphenylethane, or biphenyl (see Patent Documents 2 and 3). In order to improve the light resistance of these compounds, it is conceivable to increase the number of polymerization groups in the molecule or to add a light stabilizer. However, sufficient light resistance cannot be obtained even by such a method, and further improvement has been demanded.

JP 2002-318306 A JP 2004-315744 A JP 2005-298665 A

  In general, high refractive index properties and high light resistance tend to conflict with each other. A compound with a high refractive index has poor light resistance, and a compound with good light resistance has a low refractive index. Therefore, a compound that has both sufficiently high refractive index and high light resistance has not been found so far.

The present invention has been made in view of these points. That is, an object of the present invention is to provide a polymerizable compound capable of achieving both high refractive index and high light resistance, and a photocurable composition containing the polymerizable compound.
Another object of the present invention is to provide an optical element using an optical resin material obtained by curing the polymerizable compound, and an optical head device using the optical element.

  Other objects and advantages of the present invention will become apparent from the following description.

（式（１）において、Ａ^１、Ａ^２、Ａ^３およびＡ^４は、夫々独立して−（Ｏ）_ｍ−Ｘであり、
４個のｍは、夫々独立して０または１を表し、
４個のＸは、少なくとも３個のＸは夫々独立して、フェニル基、シクロヘキシル基、シクロヘキシルフェニル基およびフェニルシクロヘキシル基のいずれかの環基であり、環基が４個のときにはその環基はＡ^１〜Ａ^４の水素原子の内、合計して１〜４個が下記式（２）で表される置換基で置換されており、環基が３個のときには、４つ目の基Ａ^４のＸは、メチル基、ｉｓｏ−プロピル基、ｔｅｒｔ−ブチル基または下記式（２）で表される基のいずれかであり、かつ、その環基はＡ^１〜Ａ^３の水素原子及びＡ^４のＸの内、合計して１〜４個が下記式（２）で表される置換基で置換されており、かつ、Ａ^１〜Ａ^４で夫々独立してその環基の残りの水素原子の一部または全部の水素原子がメチル基、メトキシ基、フッ素原子、トリフルオロメチル基またはトリフルオロメトキシ基に置換されていてもよく、４つ目の基Ａ^４のＸが、メチル基、ｉｓｏ−プロピル基、ｔｅｒｔ−ブチル基の場合には、その水素原子の一部または全部の水素原子がフッ素原子に置換されていてもよく、

式（２）において、Ｒは、水素原子またはメチル基を表し、
Ｙは、単結合または炭素数１〜１２のアルキレン基を表し、そのアルキレン基の一部または全部の水素原子がフッ素原子またはメチル基に置換されていてもよく、そのアルキレン基の一部の炭素原子が、ケイ素原子またはゲルマニウム原子同士が隣接しない範囲内でケイ素原子またはゲルマニウム原子に置換されていてもよく、そのアルキレン基の隣接する炭素−炭素結合の間または環基と結合する末端に酸素原子を有していてもよい。） A ^first aspect of the present invention relates to a polymerizable compound characterized by being represented by the following formula (1) in which germanium and four groups A ^{1 to} A ⁴ are bonded directly or via oxygen.

(In the formula (1), A ¹ , A ² , A ³ and A ⁴ are each independently — (O) _m —X;
4 m's independently represent 0 or 1,
Four Xs are each independently a cyclic group of any one of a phenyl group, a cyclohexyl group, a cyclohexylphenyl group, and a phenylcyclohexyl group. When there are four cyclic groups, the cyclic group is A total of 1-4 of the hydrogen atoms of A ^{1 to} A ⁴ are substituted with a substituent represented by the following formula (2), and when there are three ring groups, the fourth group A X in ⁴ is any one of a methyl group, an iso-propyl group, a tert-butyl group or a group represented by the following formula (2), and the cyclic group is a hydrogen atom of A ^{1 to} A ³ and A of the ⁴ X, 1 to 4 pieces in total are substituted with a substituent represented by the following formula (2), and the remaining hydrogen in the ring group each independently with a ¹ to a ⁴ Some or all of the hydrogen atoms are methyl, methoxy, fluorine, trifluoro May be substituted by a methyl group or a trifluoromethoxy group, fourth X groups A ⁴ is methyl group, iso- propyl group, in the case of tert- butyl group, or part of the hydrogen atoms All hydrogen atoms may be replaced by fluorine atoms,

In the formula (2), R represents a hydrogen atom or a methyl group,
Y represents a single bond or an alkylene group having 1 to 12 carbon atoms, and a part or all of the hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a methyl group. The atom may be substituted with a silicon atom or a germanium atom within a range in which the silicon atom or the germanium atom is not adjacent to each other, and the oxygen atom is located between the adjacent carbon-carbon bonds of the alkylene group or at the terminal bonded to the ring group. You may have. )

  In the first aspect of the present invention, X is preferably a phenyl group which may have a substituent.

  In the first embodiment of the present invention, Y is an alkylene group having 2 to 12 carbon atoms or alkyleneoxy having 2 to 12 carbon atoms, wherein some or all of the hydrogen atoms may be substituted with fluorine atoms. It is preferably a group.

  1st aspect of this invention WHEREIN: It is preferable that the sum total of the number of the substituents represented by the said Formula (2) in the compound represented by the said Formula (1) is 1 or 2.

In the first aspect of the present invention, in all of A ^{1 to} A ⁴ , the cyclic group is preferably a phenyl group which may have a substituent, and m is preferably 0.

  According to a second aspect of the present invention, there is provided a photocurable composition comprising the polymerizable compound according to the first aspect of the present invention.

  A third aspect of the present invention relates to an optical element using a resin material obtained by curing the photocurable composition of the second aspect of the present invention.

  According to a fourth aspect of the present invention, there is provided an optical head device comprising the optical element according to the third aspect of the present invention.

  According to the first aspect of the present invention, there is provided a polymerizable compound capable of providing a resin having both high refractive index and light resistance by being contained in a composition and curing it. be able to.

  According to the 2nd form of this invention, the photocurable composition using the polymeric compound of this invention can be produced, and high refractive index property and high light resistance can be obtained by hardening | curing this composition. It is possible to provide a resin material that can satisfy both requirements.

According to the 3rd form of this invention, the optical element with favorable light resistance using the resin material formed by hardening | curing the photocurable composition of this invention can be provided.
According to the fourth aspect of the present invention, an optical head device suitable for increasing the capacity can be provided.

It is typical sectional drawing which shows an example of the wavelength selective diffraction element of embodiment of this invention. It is typical sectional drawing which shows another example of the wavelength selective diffraction element of embodiment of this invention. It is typical sectional drawing which shows the other example of the wavelength selective diffraction element of embodiment of this invention. It is a block diagram of the optical head apparatus of embodiment of this invention.

As a result of intensive studies, the present inventors have found that a resin material having both high refractive index and high light resistance can be obtained by using a germanium derivative polymerizable compound represented by the formula (1). By using this material, it is possible to provide an optical element with good light resistance and an optical head device suitable for increasing the capacity.
Hereinafter, embodiments of the present invention will be described in detail.

The polymerizable compound of the embodiment of the present invention is a polymerizable compound having a structure in which germanium represented by the formula (1) and four groups A ^{1 to} A ⁴ are bonded directly or through oxygen.

In the formula (1), A ¹ , A ² , A ³ and A ⁴ are each independently — (O) _m —X. At this time, four m's independently represent 0 or 1.

The four Xs are each independently a cyclic group of a phenyl group, a cyclohexyl group, a cyclohexylphenyl group, and a phenylcyclohexyl group, and when there are four cyclic groups, the ring A total of ^{1 to 4} of the hydrogen atoms of A ^{1 to} A ⁴ are substituted with a substituent represented by the following formula (2). When the number of ring groups is 3, the fourth group X groups ^{a 4} is methyl, iso- propyl, tert- butyl group or the following formula (2) is any of the groups represented by, and the cyclic group is a hydrogen atom ^a 1 to a ³ And a total of 1-4 of X in A ⁴ are substituted with a substituent represented by the following formula (2), and each of A ^{1 to} A ⁴ independently represents the rest of the cyclic group. Some or all of the hydrogen atoms of are methyl, methoxy, fluorine, Fluoromethyl group or may be substituted by trifluoromethoxy group, X of the fourth group A ⁴ is methyl group, iso- propyl group, in the case of tert- butyl group, a part of the hydrogen atoms Alternatively, all hydrogen atoms may be substituted with fluorine atoms.

  At this time, in Formula (2), R represents a hydrogen atom or a methyl group.

  Y represents a single bond or an alkylene group having 1 to 12 carbon atoms, and a part or all of hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a methyl group, and part of the alkylene group Carbon atoms may be substituted with silicon atoms or germanium atoms within a range in which silicon atoms or germanium atoms are not adjacent to each other, and between the adjacent carbon-carbon bonds of the alkylene group or at the terminal bonded to the ring group. It may have an oxygen atom. In addition, when there are a plurality of groups of the formula (2), the above R and Y may be the same or different within the above ranges.

In the present invention, A ^{1 to} A ⁴ have 1 to 4 substituents of the formula (2). Each of A ^{1 to} A ⁴ may have 0 to 3 substituents of the formula (2), and at least one of A ^{1 to} A ⁴ has the substituent of the formula (2) It will be. When the crosslinking density is increased, the light resistance tends to be improved. However, since the density of the phenyl group is decreased and the refractive index is decreased, in the present invention, the number of substituents of the formula (2) is 1 to Four. In particular, it is particularly preferably 1 to 2.

In one preferred form of the polymerizable compound of the present invention, it is preferable that all of the ring groups in X of A ^{1 to} A ⁴ are phenyl groups. In particular, it is preferable that X in A ^{1 to} A ⁴ is a ring group, and the ring group is a phenyl group, and has a structure represented by the following formula (3). That is, in the formula (1), A ^{1 to} A ⁴ are preferably phenyl groups because a high refractive index can be easily obtained as will be described later. Z ^{1 to} Z ⁴ are substituents of the formula (2).

In the present invention, there is a case where A ⁴ is not a cyclic group. For this reason, the 2nd preferable form in the polymeric compound of this invention is a compound of the structure shown to following formula (4). That is, in the formula (1), A ^{1 to} A ³ are phenyl groups, and X of the remaining one A ⁴ is represented by a methyl group, an iso-propyl group, a tert-butyl group or the formula (2). Any one of the substituents. Z ^{1 to} Z ⁴ are substituents of the formula (2).

In the formula (3) and formula (4), the hydrogen atoms in the remaining phenyl groups substituted with Z ^{1 to} Z ⁴ are part or all of the hydrogen atoms are methyl groups, methoxy groups, fluorine atoms, trifluoromethyl groups or It may be substituted with a trifluoromethoxy group. For example, since the transmittance in the ultraviolet wavelength region can be increased, it may be substituted with a fluorine atom, a trifluoromethyl group or a trifluoromethoxy group, and since the melting point can be lowered, it is substituted with a methyl group or a methoxy group. Also good. These can be variously selected according to the purpose. However, since the refractive index is lowered by substitution, it is preferable to use a hydrogen atom in order to obtain a high refractive index.

The substituent of formula (2) is preferably a substituent represented by the following formula (5).

In the formula (5), R represents a hydrogen atom or a methyl group. Y ¹ represents a single bond or an alkylene group represented by C _p H _2p (where p is an integer from 1 to 12), an alkyleneoxy group represented by C _q H _2q O (where q is 1) To 12), a group containing an ethyleneoxy group represented by (CH ₂ CH ₂ O) _r as a repeating unit (where r is an integer from 1 to 6), (CH ₂ CH (CH ₃ ) O ) A group containing a propyleneoxy group represented by _s as a repeating unit (wherein s is an integer from 1 to 4).
Here, a part of carbon atoms of these groups may be substituted with silicon atoms or germanium atoms. In this case, it is not preferable that silicon atoms or germanium atoms are directly bonded to each other because they are likely to be unstable. In order to avoid a high melting point, it is preferable that a hydrogen atom bonded to a silicon atom or a germanium atom is substituted with a methyl group.
In addition, when the substituent of formula (2) or formula (5) is not a substituent bonded to a ring group but X, A ⁴ bonded to a germanium atom is bonded via an oxygen atom. M is preferably 0 because it tends to be unstable.

At this time, in order to adjust the refractive index, part or all of the hydrogen atoms in the group in the formula (2) or the formula (5) may be substituted with a halogen atom, a phenyl group, a cyclohexyl group, or the like. For example, when lowering the refractive index while maintaining large wavelength dispersion, the hydrogen atom can be changed to a fluorine atom. When Y ¹ is an alkylene group, the hydrogen atom on the carbon bonded to the phenyl group may be substituted with a methyl group in order to increase the light resistance. Among these, it is preferable to use a hydrogen atom because it has both a high refractive index and an excellent balance of light resistance.

When Y ¹ has a short molecular length, the conversion rate of the polymerizable group may be low, and thus the above groups other than a single bond are preferable. Further, if p, q, r, and s are too large, the refractive index becomes small. Therefore, it is more preferable that p and q are each 1 to 6, and r and s are 1 to 2, respectively.

In the formula (3), a, b, c, and d are each independently an integer of 0 to 3, and at least one is 1 or more and does not simultaneously become zero. When the crosslink density is increased, light resistance may be improved. On the other hand, when the number of Z ¹ , Z ² , Z ³ , and Z ⁴ is too large, the density of the phenyl group is decreased and the refractive index is decreased. , A, b, c and d (a + b + c + d) is 4 or less, particularly preferably 1 or 2.

In Formula (4), when X of A ⁴ is a substituent of Formula (2) or Formula (5), a, b and c are each independently an integer of 0 to 3; , C is 3 or less (a + b + c). Further, when X of A ⁴ is not a substituent of formula (2) or formula (5), a, b and c are each independently an integer of 0 to 3, and at least one is 1 or more. At the same time. The sum (a + b + c) of a, b, and c is 3 or less. In any case, the total number of substituents of formula (2) or formula (5) as the compound is particularly preferably 1 or 2.

  The polymerizable compound of the present embodiment is preferably a compound having four phenyl groups, as shown by the formula (3), but the phenyl group has a high polarizability in order to obtain a high refractive index. The group is particularly preferably used.

  A cyclohexylphenyl group and a phenylcyclohexyl group are also preferable in that a phenyl group is included, but a phenyl group having no cyclohexyl group is particularly preferable because the density of the phenyl group decreases and the refractive index decreases. Furthermore, the compound represented by the formula (3) is preferable because the refractive index can be increased according to the number of phenyl groups and the maximum number of bonds is four.

  The polymerizable compound according to the embodiment of the present invention has a structure in which a phenyl group is bonded to germanium. We have found that light resistance in the blue LD wavelength band is superior, that is, germanium is superior in light resistance in comparison with carbon and germanium in the bond with the phenyl group. Such a fact has not been known so far. From this, while increasing the number of phenyl groups up to four and obtaining a high refractive index, the compound and resin material which are excellent in light resistance can be obtained by using germanium as an element couple | bonded with these phenyl groups.

  In the compounds of the present invention, in the formulas (2) and (5), R is a hydrogen atom or a methyl group. Accordingly, the polymerizable group becomes an acryloyloxy group or a methacryloyloxy group. The (meth) acryloyloxy group can undergo a photopolymerization reaction, has a short curing time, and is excellent in productivity. In addition, stabilization using known stabilizers such as phenolic antioxidants and hindered amine light stabilizers is possible, and there are few restrictions on usable stabilizers. Therefore, by using a (meth) acryloyloxy group as a polymerizable group, it is possible to further improve light resistance using a stabilizer. In addition, since the polymerization rate is fast, it is preferable to use an acryloyloxy group as a polymerizable group. That is, in Formula (2) and Formula (5), R is preferably a hydrogen atom.

  By using the polymerizable compound of the present embodiment, a resin material having both high refractive index and high light resistance can be obtained.

  Furthermore, in this invention, it is possible to provide the polymeric composition containing the polymeric compound of this invention. The polymerizable compound contained in this composition may be a single compound or a plurality of compounds of the formula (1). In particular, the compound of the formula (3) in the above-described embodiment is a compound having both high refractive index and high light resistance, and such properties are preferably used. On the other hand, as a compound having a low melting point, The compound of (4) can also be used. In addition, the polymerizable composition of this embodiment may contain polymerizable compounds other than the formula (1).

  The polymerizable compound other than the formula (1) may be appropriately selected depending on the purpose of adjustment such as the melting point, the viscosity, or the refractive index, and is not particularly limited. The proportion of the compound of formula (1) contained in the polymerizable compound in the composition is preferably 10 mol% or more. Thereby, a resin having a high refractive index and excellent light resistance can be obtained.

  The polymerizable composition of this embodiment may contain a reaction initiator used for the polymerization reaction. Here, examples of the polymerization reaction include a photopolymerization reaction and a thermal polymerization reaction. And the photopolymerization reaction which does not consider the thermal influence on a peripheral member is more preferable. Examples of light used for the photopolymerization reaction include ultraviolet light and visible light, and ultraviolet light is preferred because of its high polymerization rate.

  As the photopolymerization initiator, known materials can be used. For example, one or more of acetophenones, benzophenones, benzoins, benzyls, Michler ketones, benzoin alkyl ethers, and benzyl dimethyl ketals are used. It can be appropriately selected and used. The amount of the photopolymerization initiator is preferably 0.1% by mass to 5% by mass and particularly preferably 0.3% by mass to 2% by mass with respect to the total amount of the composition.

  Examples of other components that can be added to the composition of the present embodiment include stabilizers such as ultraviolet absorbers, antioxidants, and light stabilizers. These addition amounts are preferably 5% by mass or less, particularly preferably 2% by mass or less, based on the total amount of the composition.

  The composition of the present embodiment may contain an organic solvent. However, for the purpose of dilution, it is preferable to use a low-viscosity polymerizable compound instead of the organic solvent. Further, in order to facilitate handling, it is preferable to use within a range in which thermal polymerization does not occur and lower the viscosity.

  As described above, by curing the composition containing the polymerizable compound of the present invention, particularly by photocuring the photocurable composition, a resin material having both high refractive index and high light resistance is obtained. be able to.

  Furthermore, in this invention, it is possible to provide the optical element using the resin material formed by hardening | curing polymeric composition containing the polymeric compound of this invention.

  A resin having a high refractive index can be obtained using the polymerizable compound of the present invention, and can be preferably used in applications where a refractive index of a wavelength of 589 nm is required to be 1.55 or more. Conventionally, there is no optical resin material having a refractive index of 1.55 or more and excellent light resistance, and when priority is given to light resistance, no optical resin material has a refractive index of 1.55 or more. Further, when the refractive index of the resin material using the compound of the present invention is high, the wavelength dispersion of the refractive index can be increased, so that it is also preferably used in such applications.

  For example, in the polarization hologram element described in Japanese Patent Application Laid-Open No. 11-2111905, an optical index in which the refractive index is matched with one of the ordinary light refractive index and the extraordinary light refractive index of a polymer liquid crystal having a convex or concave shape. An isotropic medium is required, and the resin material according to the present invention can be used as the isotropic medium.

As another example, a wavelength selective diffraction element using the resin material of the present invention will be described. Hereinafter, the wavelength of incident light is assumed to be λ ₁ and wavelength λ ₂ (λ ₁ <λ ₂ ).

FIG. 1 is a schematic cross-sectional view showing a first aspect of a wavelength selective diffraction element according to an embodiment of the present invention. FIG. 1A is a schematic cross-sectional view showing an operation when light having a wavelength λ ₁ is incident on the wavelength selective diffraction element 1A, and FIG. 1B is a diagram showing light having a wavelength λ ₂ . It is a typical cross-sectional view which shows an effect | action when enters into the wavelength selective diffraction element 1A.

A wavelength selective diffraction element 1A shown in FIG. 1 includes a transparent substrate 11A on the surface of which a diffraction grating 12A (consisting of a concavo-convex member), which is a concavo-convex portion of the grating, and a filling member 13A filled therebetween. It is a diffraction element, and the filling member 13A is protected by the transparent substrate 14A (FIG. 1A shows a state in which light having a wavelength λ ₁ is incident, and FIG. 1B illustrates a case in which light having a wavelength λ ₂ is incident. Show the situation). Wavelength lambda equal refractive index of the diffraction grating 12A filling member 13A with respect to the _first light, the refractive index of the diffraction grating 12A and the filler member 13A is different for the wavelength lambda ₂ of light.

That is, the refractive indices of the diffraction grating 12A (consisting of the concavo-convex member) and the filling member 13A with respect to light of wavelength λ ₁ are n _12A (λ ₁ ) and n _13A (λ ₁ ), respectively, and the refractive index of light with wavelength λ ₂ is each _{n 12A (λ 2),} and _{n 13A (λ 2), n} 12A with respect to the wavelength _{λ 1 (λ 1) = n} 13A (λ 1), n 12A with respect to the wavelength λ ₂ (λ _2)> n _13A (λ ₂ )> 0.

When the wavelength lambda ₁ of the light passes through the diffraction grating 12A because the same refractive index, as shown in FIG. 1 (a), the function of the diffraction grating is straightly transmitted without generating. On the other hand, when light of wavelength λ ₂ is transmitted, it functions as a diffraction grating because the refractive index is different. As shown in FIG. 1B, the diffraction efficiency is changed depending on the height d ₁ of the diffraction grating 12A and the grating shape. The diffraction angle can be changed by changing the grating pitch of the diffraction grating 12A. Thus it is possible to realize a wavelength-selective diffraction element which has the effect of only the diffraction with respect to the wavelength lambda ₂ of light.

Here, since the transmission loss due to absorption is small, it is preferable that both the materials 12A and 13A exhibit normal dispersion in the wavelength λ ₁ and wavelength λ ₂ ranges, and n _12A (λ ₁ )> n _12A (λ ₂ ), N _13A (λ ₁ )> n _13A (λ ₂ ). That is, n _12A (λ ₁ ) = n _13A (λ ₁ )> n _12A (λ ₂ )> n _13A (λ ₂ ), and 13A has a larger chromatic dispersion (smaller Abbe number) than 12A. The resin material which is embodiment of this invention is used suitably as such a material.

Next, the wavelength selective diffraction element 1B shown in FIG. 2 will be described. FIG. 2 is a schematic cross-sectional view showing a second aspect of the wavelength selective diffraction element according to the embodiment of the present invention. FIG. 2A is a schematic cross-sectional view showing an operation when light having a wavelength λ ₁ is incident on the wavelength selective diffraction element 1B, and FIG. 2B is a diagram showing light having a wavelength λ ₂ . It is a typical cross-sectional view which shows an effect | action when is incident on the wavelength selective diffraction element 1B.

The wavelength-selective diffractive element 1B is a diffractive element including a transparent substrate 11B having a diffraction grating 12B made of a concavo-convex member formed on the surface and a filling member 13B filled therebetween. Different refractive index of the diffraction grating 12B and the filling member 13B with respect to the wavelength lambda ₁ of the light, equal to the refractive index of the diffraction grating 12B and the filling member 13B with respect to the wavelength lambda ₂ of light. Although 11A and 14A such as 11B and 14B have different alphabets, the same numerals indicate the same components as in FIG. 1 and are transparent substrates.

That is, the refractive indexes of the diffraction grating 12B and the filling member 13B with respect to light of wavelength λ ₁ are n _12B (λ ₁ ) and n _13B (λ ₁ ), respectively, and the refractive indexes of light with wavelength λ ₂ are n _12B (λ _2), and _{n 13B (λ 2), n} 13B (λ 1 with respect to the wavelength _{λ 1)> n 12B (λ} 1)> 0, also _{n 12B} with respect to the wavelength _{λ 2 (λ 2) = n} 13B ( λ ₂ ). No effect of diffraction with respect to the wavelength lambda ₂ of light, an effect of diffraction with respect to the wavelength lambda ₁ of light.

When light having a wavelength λ ₁ passes through the diffraction grating 12B, the wavelength selective diffraction element 1B functions as a diffraction grating (FIG. 2A), and is diffracted at a specific angle according to the size of the grating pitch. The diffraction efficiency of the transmission efficiency and the diffraction light of the rectilinear light can vary by changing the height d ₂ and lattice shape of the diffraction grating 12B. Meanwhile, when the light of the wavelength lambda ₂ passes is straightly transmitted without being diffracted (Figure 2 (b)). That is, it is possible to realize a wavelength-selective diffraction element which has the effect of only the diffraction with respect to the wavelength lambda ₁ of light.

Here, since transmission loss due to absorption is small, it is preferable that both the materials of 12B and 13B exhibit normal dispersion in the wavelength λ ₁ and wavelength λ ₂ ranges, and n _12B (λ ₁ )> n _12B (λ ₂ ), N _13B (λ ₁ )> n _13B (λ ₂ ). In other words, n _12B (λ ₁ )> n _13B (λ ₁ )> n _12B (λ ₂ ) = n _13B (λ ₂ ), and 12B has a larger chromatic dispersion (smaller Abbe number) than 13B. The resin material which is embodiment of this invention is used suitably as such a material.

Next, the wavelength selective diffraction element 1C shown in FIG. 3 will be described. FIG. 3 is a schematic cross-sectional view showing a third aspect of the wavelength selective diffraction element according to the embodiment of the present invention. FIG. 3A is a schematic cross-sectional view showing the operation when light having a wavelength λ ₁ is incident on the wavelength selective diffraction element 1C, and FIG. 3B is a diagram showing light having a wavelength λ ₂ . It is a typical cross-sectional view which shows an effect | action when enters into the wavelength selective diffraction element 1C.

The wavelength selective diffraction element 1C is a combination of the above-described wavelength selective diffraction elements 1A and 1B. The wavelength-selective diffractive element 1C includes a transparent substrate 11C having a diffraction grating 12C formed on the surface and a transparent substrate 16C having a diffraction grating 15C formed on the surface, and the transparent substrate 17C is formed by the filling members 13C and 14C. Has a laminated structure in which That is, the transparent substrate 11C, the diffraction grating 12C, the filling member 13C, and the transparent substrate 17C in FIG. 3 correspond to the transparent substrate 11A, the diffraction grating 12A, the filling member 13A, and the transparent substrate 14A in FIG. Further, the transparent substrate 16C, the diffraction grating 15C, the filling member 14C, and the transparent substrate 17C in FIG. 3 correspond to the transparent substrate 11B, the diffraction grating 12B, the filling member 13B, and the transparent substrate 14B in FIG. Here, with respect to the wavelength lambda ₁ of the light equal to the refractive index of the diffraction grating 12C and the filling member 13C, the refractive index of the diffraction grating 12C filling member 13C with respect to the wavelength lambda ₂ of light is different.

Also, different refractive index of the diffraction grating 15C and the filling member 14C with respect to the wavelength lambda ₁ of the light, equal to the refractive index of the diffraction grating 15C and the filling member 14C with respect to the wavelength lambda ₂ of light. Accordingly, as shown in FIG. 2A for the upper portion of the wavelength selective diffraction element 1C shown in FIG. 3A and for the lower portion of FIG. 1A, the light of wavelength λ ₁ is a diffraction grating. It is diffracted at 15C, passes through the diffraction grating 12C, and only 15C acts as a diffraction grating.

On the other hand, and FIG. 3 (b) the upper portion of the wavelength-selective diffraction element 1C shown is FIG. 2 (b), as shown FIG. 1 the lower part (b), respectively, light of the wavelength lambda ₂ is diffracted grating The light passes through 15C and is diffracted by the diffraction grating 12C, and only 12C acts as the diffraction grating. Therefore, each composite element functions as a diffraction element independently for two types of wavelengths.

Here, it is assumed that the wavelength λ ₁ and the wavelength λ ₂ are a 405 nm wavelength band used for BD and a 660 nm wavelength band used for DVD, respectively. In the case of the relationship described in FIG. 1, a wavelength selective diffraction element that transmits the 405 nm wavelength band and diffracts the 660 nm wavelength band can be manufactured. Furthermore, since the 785 nm wavelength band used in CD (Compact Disk) has a refractive index close to that of the 660 nm wavelength band, a wavelength selective diffraction element that diffracts even in the 785 nm wavelength band can be manufactured.

  In the case of the relationship described in FIG. 2, a wavelength selective diffraction element that diffracts the 405 nm wavelength band and transmits the 660 nm wavelength band can be manufactured. Further, since the refractive index of the 785 nm wavelength band is close to that of the 660 nm wavelength band, a wavelength selective diffraction element that transmits light even in the 785 nm wavelength band can be manufactured.

In the wavelength selective diffractive element described above, the diffraction efficiency can be changed by changing the grating height d ₁ , d ₂ or the grating shape, so that it is suitable as a three-beam generating element or a hologram beam splitter. It is sufficient to use a grid height that provides In addition, the concavo-convex portion of the wavelength selective diffractive element may be used in a blazed grating shape or a stepped grating shape having a multi-level structure to enhance the diffraction efficiency of a specific order. The diffraction angle may also be set to a grating pitch that achieves a desired diffraction angle, and these methods can be used for wavelength selective diffraction elements as they are, as they are for conventional three-beam generating elements and hologram beam splitters. .

  In addition, in the wavelength-selective polarization hologram element as described in Japanese Patent Application Laid-Open No. 2005-209327, any one of the left and right circularly polarized light out of the refractive index wavelength dispersion of the cholesteric polymer liquid crystal having a convex or concave shape with respect to the circularly polarized light The resin material according to the present invention can be used as an optically isotropic medium matched with the above.

  Furthermore, the resin material obtained by polymerizing the composition of the present invention can be used for optical elements such as other diffraction elements and lenses in addition to the above-described diffraction elements. This material is not limited to the manufacturing method of these optical elements, and may be a conventionally known method. Furthermore, it can also be used as an adhesive for laminating optical elements and fixing optical components.

  Since the material of the present invention and an element using the material are excellent in light resistance to a blue laser, it is preferably used in an optical pickup application, and an optical head device suitable for increasing the capacity can be produced. That is, the optical element using the resin material according to the embodiment of the present invention is suitable for an optical head device that records information on an optical recording medium and / or reproduces information recorded on the optical recording medium, and particularly BD. (Blu-ray Disk) and HDDVD (High-Definition Digital Versatile Disk) are suitable for an optical head device for an optical information recording / reproducing apparatus using a blue laser. Specifically, it is preferably arranged in the optical path of the laser beam of the optical head device. In addition, it can be suitably used in other applications that conventionally require a high refractive index resin.

The optical head device according to the embodiment of the present invention will be described below.
FIG. 4 is a configuration diagram of an optical head device according to an embodiment of the present invention. As shown in this figure, the optical head device 111 includes a light source 112 that emits laser light, a wavelength selective diffraction grating 113, a beam splitter 114 that transmits laser light, and a collimator lens 115 that collimates the laser light. And an objective lens 118 that collects light on the recording layer 117 of the optical disc 116 and a photodetector 119 that detects reflected light from the optical disc 116. The optical head device 111 uses three beams in tracking control when reading information recorded on a BD or the like. The wavelength-selective diffraction grating 113 is a three-beam generating diffraction grating, and an optical element (wavelength-selective diffraction grating 1B in FIG. 2) according to an embodiment of the present invention is applied.

  In FIG. 4, the wavelength selective diffraction grating 113 is provided between the light source 112 and the beam splitter 114. However, the wavelength selective diffraction grating 113 may be provided between the beam splitter 114 and the objective lens 118. Any wavelength-selective diffraction grating 113 may be provided in the optical path between the light source 112 and the objective lens 118. If the wavelength selective diffraction grating 113 is arranged between the light source 112 and the beam splitter 114 as shown in FIG. 4, the reflected light from the optical disk is guided to the photodetector 119 without being diffracted by the wavelength selective diffraction grating 113. Therefore, the light utilization efficiency is increased, which is preferable.

  The light source 112 is composed of, for example, a semiconductor laser diode, and generates laser light having a wavelength corresponding to the type of the optical disk 116 and emits it to the wavelength selective diffraction grating 113. As the light source 112, an ordinary laser light source used in an ordinary optical head device is used. Specifically, a semiconductor laser is suitable, but other lasers may be used. Since the resin material obtained in the present invention has good light resistance against a blue laser, the capacity of the optical head device can be increased by using the blue laser as a light source.

In the present embodiment, the wavelength of the laser light is, for example, 405 nm (wavelength λ ₁ ) and 660 nm (wavelength λ ₂ ). A plurality of light sources that emit laser beams having different wavelengths may be provided, and laser light may be emitted from each light source to the wavelength selective diffraction grating 113.

The wavelength-selective diffraction grating 113 includes three beams including light that has been transmitted without diffracting the laser light having the wavelength λ ₁ (0th-order diffracted light) and light that has been diffracted from the laser light having the wavelength λ ₁ (± first-order diffracted light). The beam is output to the beam splitter 114. Further, the wavelength selective diffraction grating 113 transmits the laser beam having the wavelength λ ₂ and outputs it to the beam splitter 114.

The beam splitter 114 is made of a transmissive material, such as glass or plastic, and includes a reflective surface that reflects the reflected light from the optical disk 116.
The collimator lens 115 is also made of a transparent material such as glass or plastic, and collimates the incident laser beam.

  The objective lens 118 has a predetermined numerical aperture NA, and condenses incident light from the collimator lens 115 on the recording layer 117 of the optical disk 116 and captures reflected light from the recording layer 117.

The photodetector 119 includes a lens, a photodiode, and the like, and converts the reflected light from the optical disk 116 reflected by the reflecting surface of the beam splitter 114 into an electric signal. The photodetector 119 receives three beams of reflected light having a wavelength λ ₁ and receives a main beam generated by the 0th-order diffracted light and two sub beams generated by the ± 1st-order diffracted light. A tracking error is detected based on the light amount difference between the two sub beams and is output to a tracking control unit (not shown).

When the optical disk 116 is a BD, the optical head device 111 operates as follows.
First, the light of wavelength λ ₁ emitted from the light source 112 is partially diffracted by the wavelength selective diffraction grating 113. Thereby, light including 0th order diffracted light and ± 1st order diffracted light is emitted from the wavelength selective diffraction grating 113, passes through the beam splitter 114, and is collimated by the collimator lens 115.

  The parallel light emitted from the collimator lens 115 is condensed on the information recording track of the optical disk 116 by the objective lens 118 into three beams of 0th order diffracted light and ± 1st order diffracted light. Next, the light reflected by the optical disk 116 is transmitted again from the objective lens 118 through the collimator lens 115 and reflected by the beam splitter 114, and is generated by the main beam generated by the 0th order diffracted light and the ± 1st order diffracted light. The two sub beams are condensed on the light receiving surface of the photodetector 119. Then, the photodetector 119 detects a tracking error signal based on the light amount difference between the two sub beams and outputs it to a tracking control unit (not shown).

When the optical disk 116 is a DVD, the optical head device 111 operates as follows.
First, light having a wavelength λ ₂ emitted from the light source 112 passes through the wavelength selective diffraction grating 113 without being diffracted, and further passes through the beam splitter 114 to be collimated by the collimator lens 115. Thereafter, the parallel light is condensed on the information recording track of the optical disk 116 by the objective lens 118. Then, the light reflected by the optical disk 116 passes through the objective lens 118 and the collimator lens 115 again, is reflected by the beam splitter 114, and is collected on the light receiving surface of the photodetector 119.

As described above, a highly reliable optical head device suitable for increasing the capacity is configured by curing the composition containing the polymerizable compound of the present invention and using an optical element using the resulting resin material. Can do.
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  Below, the Example and comparative example of this invention are described. However, the present invention is not limited to the following examples.

<Synthesis of polymerizable compound>
Example 1
A polymerizable compound A was synthesized through compounds A-1, A-2, A-3 and A-4 according to the method shown in the synthesis scheme below.

In the above formula, TBDMS represents a tert-butyldimethylsilyl group.
Hereinafter, each reaction of the said synthetic scheme in the polymeric compound A is demonstrated in detail.

(A) Synthesis of Compound A-1 In 200 mL of tetrahydrofuran (hereinafter referred to as THF), 5.0 g (29 mmol) of 4-bromophenol and 4.8 mL (35 mmol) of triethylamine were dissolved and stirred. Then, 6.5 g (43 mmol) of tert-butyldimethylchlorosilane (hereinafter referred to as TBDMS-Cl) dissolved in 100 mL of THF was slowly added dropwise over 10 minutes and reacted at room temperature for 12 hours. Next, water and ethyl acetate were added to extract the organic layer, and magnesium sulfate was further added and dried sufficiently, and then the solvent was distilled off. Purification by column chromatography was performed using ethyl acetate and hexane (volume ratio 1: 9) to obtain 6.1 g of a colorless transparent liquid compound A-1. The yield was 72%.

(B) Synthesis of Compound A-2 4.6 g (16 mmol) of Compound A-1 was dissolved in 100 mL of THF and stirred at −30 ° C. in a nitrogen atmosphere. Next, 10 mL (16 mmol) of an n-butyllithium hexane solution having a concentration of 1.6 mol / L was slowly added dropwise over about 5 minutes. After reacting at −30 ° C. for 20 minutes, 5 g (15 mmol) of triphenylchlorogermane dissolved in 100 mL of THF was slowly added dropwise over about 10 minutes. Then, after hold | maintaining for 15 minutes at -30 degreeC, it was made to react at room temperature for 3 hours. Next, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1: 8) was performed to obtain 5.1 g of white solid compound A-2. The yield was 62%.

(C) Synthesis of Compound A-3 In 100 mL of THF, 3.4 g (6.6 mmol) of Compound A-2 and 1.9 g (7.2 mmol) of tetrabutylammonium fluoride (hereinafter referred to as TBAF) Were dissolved and stirred at room temperature for 3 hours. Thereafter, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1: 3) was performed to obtain 2.1 g of white solid compound A-3. The yield was 79%.

(D) Synthesis of Compound A-4 To 100 mL of acetone and 100 mL of N, N-dimethylformamide (hereinafter referred to as DMF), 1.3 g (5.0 mmol) of Compound A-3, 5.3 g of cesium carbonate ( 16 mmol), 0.30 mL (4.2 mmol) of 2-bromoethanol and 0.3 g (1.2 mmol) of potassium iodide were added and reacted at 50 ° C. for 12 hours. Next, water and ethyl acetate were added to extract the organic layer, and magnesium sulfate was further added and dried sufficiently, and then the solvent was distilled off. Purification by column chromatography was performed using ethyl acetate and hexane (volume ratio 1: 3) to obtain 1.0 g of white solid compound A-4. The yield was 69%.

(E) Synthesis of Compound A 1.0 g (2.2 mmol) of Compound A-4 and 0.38 mL (2.7 mmol) of triethylamine were dissolved in 50 mL of THF, and the mixture was placed in a nitrogen atmosphere for 2 minutes in a water bath. Slowly, 0.20 mL (2.5 mmol) of acrylic acid chloride was dripped slowly. Thereafter, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1: 6) was performed to obtain 0.75 g of Compound A as a white solid. The yield was 67%.

The spectral data of 1H-NMR spectrum of the polymerizable compound A (solvent: CDCl ₃ , internal standard: tetramethoxysilane (TMS)) are δ (ppm): 4.22 (2H, t), 4.50 (2H, t), 5.84-6.46 (3H, m), 6.94-7.53 (19H, m). Compound A thus obtained had a melting point of 100 ° C.

Example 2
Compound B was synthesized through compounds B-1, B-2, B-3 and B-4 according to the synthesis scheme shown below.

Hereinafter, each reaction of the said synthetic scheme in the polymeric compound B is demonstrated in detail.
(A) Synthesis of Compound B-1 In 200 mL of acetone and 100 mL of DMF, 5.0 g (29 mmol) of 3-bromophenol, 28 g (86 mmol) of cesium carbonate, 4.2 mL (59 mmol) of 2-bromoethanol, 0.3 g (1.2 mmol) of potassium iodide was added and reacted at 50 ° C. for 12 hours. Next, water and ethyl acetate were added to extract the organic layer, and magnesium sulfate was further added and dried sufficiently, and then the solvent was distilled off. Purification by column chromatography was performed using ethyl acetate and hexane (volume ratio 1: 2) to obtain 4.8 g of colorless transparent liquid compound B-1. The yield was 77%.

(B) Synthesis of Compound B-2 4.8 g (22 mmol) of Compound B-1 and 3.3 mL (24 mmol) of triethylamine were dissolved in 200 mL of THF and stirred, and then dissolved in 100 mL of THF 3 0.7 g (25 mmol) of tert-butyldimethylchlorosilane was slowly added dropwise over 10 minutes, and the mixture was reacted at room temperature for 12 hours. Next, water and ethyl acetate were added to extract the organic layer, and magnesium sulfate was further added and dried sufficiently, and then the solvent was distilled off. Purification by column chromatography was performed using ethyl acetate and hexane (volume ratio 1: 6) to obtain 4.1 g of colorless transparent liquid compound B-2. The yield was 56%.

(C) Synthesis of Compound B-3 4.1 g (12 mmol) of Compound B-2 was dissolved in 100 mL of THF and stirred at −30 ° C. in a nitrogen atmosphere. Next, 7.8 mL (12 mmol) of an n-butyllithium hexane solution having a concentration of 1.6 mol / L was slowly added dropwise over about 3 minutes. After reacting at −30 ° C. for 20 minutes, 4.2 g (12 mmol) of triphenylchlorogermane dissolved in 100 mL of THF was slowly added dropwise over about 10 minutes. Then, after hold | maintaining for 15 minutes at -30 degreeC, it was made to react at room temperature for 3 hours. Next, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1:19) was performed to obtain 4.5 g of white solid compound B-3. The yield was 65%.

(D) Synthesis of Compound B-4 In 100 mL of THF, 4.5 g (8.1 mmol) of Compound B-3 and 2.4 g (9.2 mmol) of TBAF were dissolved and stirred at room temperature for 3 hours. . Thereafter, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1: 2) was performed to obtain 2.3 g of white solid compound B-4. The yield was 64%.

(E) Synthesis of Compound B In 100 mL of THF, 2.3 g (5.2 mmol) of Compound B-4 and 0.80 mL (5.7 mmol) of triethylamine were dissolved, and the mixture was placed in a nitrogen atmosphere for 5 minutes in a water bath. Slowly, 0.46 mL (5.6 mmol) of acrylic acid chloride was added dropwise over a certain degree. Thereafter, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1: 9) was performed to obtain 1.6 g of Compound B as a white solid. The yield was 62%.

The spectral data of the 1H-NMR spectrum (solvent: CDCl ₃ , internal standard: TMS) of Compound B are δ (ppm): 4.13 (2H, t), 4.46 (2H, t), 5.81- 6.44 (3H, m), 6.95 (1H, m), 7.09-7.15 (2H, m), 7.30-7.54 (16H, m). Compound B thus obtained had a melting point of 75 ° C.

Example 3
Compound C was synthesized via compounds C-1, C-2 and C-3 according to the synthesis scheme shown below.

Hereinafter, each reaction of the said synthetic scheme in the polymeric compound C is demonstrated in detail.
(A) Synthesis of Compound C-1 In 200 mL of THF, 5.0 g (25 mmol) of 2- (4-bromophenyl) ethyl alcohol and 4.1 mL (30 mmol) of triethylamine were dissolved and stirred. 5.6 g (37 mmol) of tert-butyldimethylchlorosilane dissolved in 100 mL of THF was slowly added dropwise over 10 minutes and reacted at room temperature for 12 hours. Next, water and ethyl acetate were added to extract the organic layer, and magnesium sulfate was further added and dried sufficiently, and then the solvent was distilled off. Purification by column chromatography was performed using ethyl acetate and hexane (volume ratio 1:19) to obtain 6.2 g of colorless transparent liquid compound C-1. The yield was 79%.

(B) Synthesis of Compound C-2 4.6 g (15 mmol) of Compound C-1 was dissolved in 100 mL of THF and stirred at −30 ° C. in a nitrogen atmosphere. Next, 9.2 mL (15 mmol) of an n-butyllithium hexane solution having a concentration of 1.6 mol / L was slowly added dropwise over about 5 minutes. After reacting at −30 ° C. for 20 minutes, 5.0 g (15 mmol) of triphenylchlorogermane dissolved in 100 mL of THF was slowly added dropwise over about 10 minutes. Then, after hold | maintaining for 15 minutes at -30 degreeC, it was made to react at room temperature for 3 hours. Next, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1:19) was performed to obtain 6.2 g of white solid compound C-2. The yield was 78%.

(C) Synthesis of Compound C-3 6.2 g (11 mmol) of Compound C-2 and 3.6 g (14 mmol) of TBAF were dissolved in 100 mL of THF and stirred at room temperature for 3 hours. Thereafter, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1: 2) was performed to obtain 3.5 g of white solid compound C-3. The yield was 72%.

(D) Synthesis of Compound C In 100 mL of THF, 3.5 g (8.2 mmol) of Compound C-3 and 1.3 mL (9.4 mmol) of triethylamine were dissolved, and the mixture was placed in a nitrogen atmosphere for 5 minutes in a water bath. Slowly, 0.73 mL (9.0 mmol) of acrylic acid chloride was added dropwise over a period of time. Thereafter, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1: 6) was performed to obtain 3.0 g of white solid compound C. The yield was 76%.

The spectral data of the 1H-NMR spectrum (solvent: CDCl ₃ , internal standard: TMS) of Compound C are δ (ppm): 2.99 (2H, t), 4.38 (2H, t), 5.30- 6.41 (3H, m), 7.24-7.53 (19H, m). The melting point of Compound C obtained was 123 ° C.

Example 4
Compound D was synthesized via compounds D-1, D-2 and D-3 according to the synthesis scheme shown below.

Hereinafter, each reaction of the said synthetic scheme in the polymeric compound D is demonstrated in detail.
(A) Synthesis of Compound D-1 After dissolving 12.0 g (64.5 mmol) of 4-bromobenzyl alcohol and 10.7 mL (77.3 mmol) of triethylamine in 200 mL of THF, 100 mL of THF was dissolved. 14.6 g (96.7 mmol) of tert-butyldimethylchlorosilane dissolved in was slowly added dropwise over 10 minutes and allowed to react at room temperature for 12 hours. Next, water and ethyl acetate were added to extract the organic layer, and magnesium sulfate was further added and dried sufficiently, and then the solvent was distilled off. Purification by column chromatography was performed using ethyl acetate and hexane (volume ratio 1:19) to obtain 13.0 g of colorless transparent liquid compound D-1. The yield was 67.2%.

(B) Synthesis of Compound D-2 4.4 g (15 mmol) of Compound D-1 was dissolved in 100 mL of THF and stirred at −30 ° C. in a nitrogen atmosphere. Next, 9.2 mL (15 mmol) of an n-butyllithium hexane solution having a concentration of 1.6 mol / L was slowly added dropwise over about 5 minutes. After reacting at −30 ° C. for 20 minutes, 5.0 g (15 mmol) of triphenylchlorogermane dissolved in 100 mL of THF was slowly added dropwise over about 10 minutes. Then, after hold | maintaining for 15 minutes at -30 degreeC, it was made to react at room temperature for 3 hours. Next, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1:19) was performed to obtain 4.9 g of white solid compound D-2. The yield was 64%.

(C) Synthesis of Compound D-3 4.9 g (9.3 mmol) of Compound D-2 and 2.7 g (10 mmol) of TBAF were dissolved in 100 mL of THF and stirred at room temperature for 3 hours. Thereafter, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1: 2) was performed to obtain 3.0 g of white solid compound D-3. The yield was 78%.

(D) Synthesis of Compound D In 100 mL of THF, 3.0 g (7.3 mmol) of Compound D-3 and 1.1 mL (8.0 mmol) of triethylamine were dissolved, and the mixture was placed in a nitrogen atmosphere for 5 minutes in a water bath. Slowly, 0.66 mL (8.2 mmol) of acrylic acid chloride was added dropwise over a certain degree. Thereafter, water and ethyl acetate were added to extract the organic layer. Magnesium sulfate was added and sufficiently dried, and then the solvent was distilled off. Purification by column chromatography using ethyl acetate and hexane (volume ratio 1: 6) was performed to obtain 1.7 g of Compound D as a white solid. The yield was 50%.

The spectral data of the 1H-NMR spectrum of Compound D (solvent: CDCl ₃ , internal standard: TMS) are δ (ppm): 5.22 (2H, s), 5.84-6.48 (3H, m), 7.37-7.55 (19H, m). The melting point of Compound D obtained was 124 ° C.

Example 5
Compound E was synthesized via compounds E-1 and E-2 according to the synthesis scheme shown below.

Hereinafter, each reaction of the said synthetic scheme in the polymeric compound E is demonstrated in detail.
(A) Synthesis of Compound E-1 In 200 mL of THF, 5.0 g (15 mmol) of triphenylchlorogermane was dissolved, and 15 mL (15 mmol) of 1 mol / L allylmagnesium bromide THF solution was added under an ice bath in a nitrogen atmosphere. The solution was slowly added dropwise over about 10 minutes, and then reacted at room temperature for 5 hours. Next, water and ethyl acetate were added to extract the organic layer, and magnesium sulfate was further added and dried sufficiently, and then the solvent was distilled off. Purification by column chromatography was performed using ethyl acetate and hexane (volume ratio 1: 9) to obtain 2.7 g of colorless transparent liquid compound E-1. The yield was 53%.

(B) Synthesis of Compound E-2 To 20 mL of THF, 8.6 mL (7.8 mmol) of 0.9 mol / L borane THF solution was added, and 2.7 g (7.8 mmol) was added under an ice bath in a nitrogen atmosphere. Compound E-1 was slowly added dropwise over about 10 minutes, and then allowed to react at room temperature for 3 hours. Next, 4.0 g of sodium hydroxide dissolved in 40 mL of water was slowly added dropwise over 5 minutes in a water bath, and 15 mL of 30% hydrogen peroxide was slowly added dropwise over about 10 minutes in the water bath. Water and ethyl acetate were added to extract the organic layer, and magnesium sulfate was further added and dried sufficiently, and then the solvent was distilled off. Purification by column chromatography was performed using ethyl acetate and hexane (volume ratio 4: 1) to obtain 2.5 g of white solid compound E-2. The yield was 88%.

(C) Synthesis of Compound E 1.8 g (4.9 mmol) of Compound E-2 and 0.8 mL (5.8 mmol) of triethylamine were dissolved in 100 ml of THF, and dissolved in 10 mL of THF under an ice bath in a nitrogen atmosphere. 0.5 mL (6.2 mmol) of acrylic acid chloride was slowly added dropwise over about 10 minutes, and then reacted at room temperature for 3 hours. Water and ethyl acetate were added to extract the organic layer, and magnesium sulfate was further added and dried sufficiently, and then the solvent was distilled off. Purification by column chromatography was performed using ethyl acetate and hexane (volume ratio 1: 6) to obtain 1.4 g of Compound E as a white solid. The yield was 68%.

The spectral data of the 1H-NMR spectrum (solvent: CDCl ₃ , internal standard: TMS) of Compound E are δ (ppm): 1.51-1.59 (2H, t), 1.86-1.93 (2H Dd), 4.13-4.16 (2H, t), 5.79-6.41 (3H, m), 7.27-7.49 (15H, m). The melting point of Compound D obtained was 86 ° C.

<Polymerization of photocurable composition and evaluation of refractive index>
Example 6
0.5 parts by weight of “IC184” (trade name) manufactured by Ciba Specialty Chemicals as a photoinitiator was added to 100 parts by weight of Compound A, and the mixture was stirred while heating until uniform. And the photocurable composition A was obtained.

Next, four corners of two glass plates were bonded together with an adhesive mixed with glass beads having a diameter of 10 μm to produce a glass cell having a glass interval of 10 μm. After the composition A was injected into the glass cell in a liquid state, the glass plate was irradiated with ultraviolet rays for 2 minutes from the vertical direction to obtain a cell A. The illuminance of the high-pressure mercury lamp used was 50 mW / cm ² at a wavelength of 365 nm. Thereafter, one of the two glass plates of the cell A was peeled off using a cutter to obtain a test piece A having a cured resin on one side. Using a prism coupler (manufactured by Metricon: Model 2010), the refractive indices at wavelengths of 404 nm, 633 nm, and 791 nm were measured at room temperature, which were 1.669, 1.621, and 1.611, respectively. It was confirmed that there was.

Next, based on the refractive indices of the three wavelengths, fitting parameters A, B, and C of Cauchy's dispersion formula (n (λ) = A + B / λ ² + C / λ ⁴ ) using the least square method It derives the refractive index in 400nm~800nm by obtaining from, calculation of the refractive index at 589nm fitting value based on _{n d,} and Abbe number [nu _{d, n d} is 1.625, [nu _d 26. It was 9.

Examples 7-10
Photocurable compositions B, C, D and E were obtained in the same manner as in Example 6 except that compounds B, C, D and E were used in place of compound A, and cells B, C, D and After obtaining E, test pieces B, C, D, and E were prepared by peeling the glass on one side of the cell. Specimens B, C, D, and E were measured refractive index at room temperature, was calculated _{n d} and [nu _d, respectively, the refractive index _{n d} of 589nm is 1.629,1.630,1.633,1 .615, the Abbe number [nu _d is 26.6,26.5,26.0,29.4, it was confirmed that the resin of high refractive index.

<Polymerization of photocurable composition and evaluation of light resistance>
Example 11
Same as Example 6 except that a glass plate coated with an antireflection film on one surface was used, the surface opposite to the coating surface was opposed, and the diameter of the glass beads mixed with the adhesive was changed to 20 μm. Thus, a glass cell was produced. 0.5 parts by weight of “IC184” (trade name) manufactured by Ciba Specialty Chemicals as a photoinitiator is added to 100 parts by weight of Compound A, and the mixture is stirred until it is uniform while heating to obtain a liquid photocurable composition. A was obtained. The obtained composition was poured into the above glass cell in a liquid state, and a laminate A was obtained by irradiating ultraviolet rays from the direction perpendicular to the glass plate for 2 minutes. The illuminance of the high-pressure mercury lamp used was 50 mW / cm ² at a wavelength of 365 nm.

The laminate A was irradiated with blue LD light having an oscillation wavelength of 406 nm at 80 ° C. for 15 kJ / mm ² . When the transmittance was measured before and after the irradiation, the transmittance change ΔT _LD was 2.0%. Here, ΔT _LD = (blue LD light transmittance before irradiation) − (blue LD light transmittance after irradiation).

Examples 12-15
Laminates B, C, D and E were produced in the same manner as in Example 11 except that compound B or C or D or E was used in place of compound A. The ΔT _LD of the laminates B, C, D and E was measured in the same manner as in Example 13. As a result, the laminate B was 2.6%, the laminate C was less than 1%, and the laminate D was 2.6. % And Laminate E was less than 1%.

Comparative Example 1
A resin was prepared in the same manner as in Example 6 except that the following compound F was used in place of the compound A. When the refractive index was measured at room temperature, the refractive index at 589 nm was 1.608, and the Abbe number ν _d was 28.2.

A cell F was produced in the same manner as in Example 6 except that the compound F was used in place of the compound A. Subsequently, the transmittance of the laminate F was measured in the same manner as in Example 11, and ΔT _LD was 59%.

Comparative Example 2
A resin was prepared in the same manner as in Example 6 except that the following compound G was used instead of the compound A. When the refractive index was measured at room temperature, the refractive index at 589 nm was 1.625, and the Abbe number ν _d was 27.2.

A cell G was produced in the same manner as in Example 6 except that the compound G was used instead of the compound A. Subsequently, when the transmittance | permeability change of the laminated body G was measured like Example 11, (DELTA) _TLD was 42%.

Table 1 compares the evaluation results of Examples 6 to 15 and Comparative Examples 1 and 2. Refractive index n _d , Abbe number ν _d of the resins of Examples 6 to 10 obtained using the polymerizable compounds A, B, C, D and E of Examples 1 to 5 and the corresponding laminate A Table 1 summarizes the transmittance change ΔT _LD of ˜E (Examples 11 to 15). In addition, the same evaluation was performed on the resins using Compound F (Comparative Example 1) and Compound G (Comparative Example 2), which are comparative examples of the present invention, and are summarized in Table 1.

  As can be seen from this table, it was found that the resin material obtained using the polymerizable compound of the present invention is excellent in light resistance while realizing a high refractive index equal to or higher than that of the conventional material.

Table 1

  The material of the present invention has a high refractive index and can be used for various optical applications. In particular, since the material has high light resistance against blue light, high refractive index materials such as optical disks and optical elements using strong blue light can be used. It can be suitably used for required applications.

1A, 1B, 1C, 113 Wavelength selective diffraction element 11A, 14A, 11B, 14B, 11C, 16C, 17C Transparent substrate 12A, 12B, 12C, 15C Diffraction grating 13A, 13B, 13C, 14C Filling member 111 Optical head device 112 Light source 114 Beam splitter 115 Collimator lens 116 Optical disc 117 Recording layer 118 Objective lens 119 Photo detector

Claims (8)

A polymerizable compound represented by the following formula (1) in which germanium and four groups A ^{1 to} A ⁴ are bonded directly or through oxygen.

(In the formula (1), A ¹ , A ² , A ³ and A ⁴ are each independently — (O) _m —X;
4 m's independently represent 0 or 1,
Four Xs are each independently a cyclic group of any one of a phenyl group, a cyclohexyl group, a cyclohexylphenyl group, and a phenylcyclohexyl group. When there are four cyclic groups, the cyclic group is A total of 1-4 of the hydrogen atoms of A ^{1 to} A ⁴ are substituted with a substituent represented by the following formula (2), and when there are three ring groups, the fourth group A X in ⁴ is any one of a methyl group, an iso-propyl group, a tert-butyl group or a group represented by the following formula (2), and the cyclic group is a hydrogen atom of A ^{1 to} A ³ and A of the ⁴ X, 1 to 4 pieces in total are substituted with a substituent represented by the following formula (2), and the remaining hydrogen in the ring group each independently with a ¹ to a ⁴ Some or all of the hydrogen atoms are methyl, methoxy, fluorine, trifluoro May be substituted by a methyl group or a trifluoromethoxy group, fourth X groups A ⁴ is methyl group, iso- propyl group, in the case of tert- butyl group, or part of the hydrogen atoms All hydrogen atoms may be replaced by fluorine atoms,

In the formula (2), R represents a hydrogen atom or a methyl group,
Y represents a single bond or an alkylene group having 1 to 12 carbon atoms, and a part or all of the hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a methyl group. The atom may be substituted with a silicon atom or a germanium atom within a range in which the silicon atom or the germanium atom is not adjacent to each other, and the oxygen atom is located between the adjacent carbon-carbon bonds of the alkylene group or at the terminal bonded to the ring group. You may have. )   The polymerizable compound according to claim 1, wherein X is a phenyl group which may have a substituent.   Y is an alkylene group having 2 to 12 carbon atoms or an alkyleneoxy group having 2 to 12 carbon atoms, wherein some or all of the hydrogen atoms may be substituted with fluorine atoms. Item 3. The polymerizable compound according to Item 1 or 2.   4. The polymerizable compound according to claim 1, wherein the sum of the number of substituents represented by the formula (2) in the compound represented by the formula (1) is 1 or 2. 5. The polymerization according to any one of claims 1 to 4, wherein in all of A ^{1 to} A ⁴ , the cyclic group is a phenyl group which may have a substituent, and m is 0. Sex compounds.   A photocurable composition comprising the polymerizable compound according to claim 1.   An optical element using a resin material obtained by curing the photocurable composition according to claim 6.   An optical head device comprising the optical element according to claim 7.

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