WO2008065862A1

WO2008065862A1 - Plastic optical device material, plastic optical device made of the same, and optical pickup device

Info

Publication number: WO2008065862A1
Application number: PCT/JP2007/071629
Authority: WO
Inventors: Yasumitsu Fujino; Hiroko Omori
Original assignee: Konica Minolta Opto, Inc.
Priority date: 2006-12-01
Filing date: 2007-11-07
Publication date: 2008-06-05

Abstract

Disclosed is a plastic optical device material having improved optical stability and excellent transparency, which is capable of maintaining such characteristics for a long time. Also disclosed are a plastic optical device made of such a material, and an optical pickup device using such a plastic optical device and having good pickup characteristics. The plastic optical device material is characterized by being a resin composition which contains a polymer obtained by copolymerizing a mixture composed of at least one cage silsesquioxane having a reactive group, at least one inorganic particle having a reactive group, and at least one polyfunctional compound having two or more reactive groups.

Description

Specification

Plastic optical element material, plastic optical element using the same, and optical pickup device

Technical field

TECHNICAL FIELD [0001] The present invention relates to a plastic optical element material suitably used for a plastic optical element and the like, a plastic optical element using the same, and an optical pickup device to which the plastic optical element is applied.

Background art

Conventionally, optical pickups are used for recording devices such as players, recorders, and drives that read and record information on MO, CD, DVD, and other optical information recording media (hereinafter also referred to as media). A device is provided. The optical pickup device includes an optical element unit that irradiates a medium with light having a predetermined wavelength emitted from a light source, and receives the reflected light with a light receiving element. The optical element unit receives the light from the reflection layer of the medium. Have an optical element such as a lens to collect light with the element!

[0003] The optical element of the optical pickup device is preferably made of plastic as a material in that it can be manufactured at low cost by means such as injection molding. As plastics to which optical elements can be applied, a copolymer of cyclic olefin and α-olefin is known (for example, see Patent Document 1).

[0004] By the way, in the case of an information device capable of reading and writing information on a plurality of types of media such as a CD / DVD player, for example, the optical pickup device has the shape of both media and the wavelength of light to be applied. It is necessary to make the configuration corresponding to the difference. In this case, it is preferable from the viewpoint of cost and pickup characteristics that the optical element unit is common to all the media.

[0005] In recent years, as a medium capable of recording information at a higher density than CD and DVD, information can be recorded at a shorter wavelength than that used for CD (λ = 780nm) and DVD (= 635 and 650nm). Development of media such as Blu-ray Discs for playback and information devices that read and write information on these media is newly underway. [0006] However, in so-called next-generation DVDs such as Blu-ray Discs, light having a wavelength of around 400 nm is used for recording and reproducing information, so that the optical element is made of the thermoplastic resin described in Patent Document 1 above. Then, the optical element is affected by such short-wavelength light irradiation and the accompanying heat, and itself becomes cloudy or the optical surface is deformed, resulting in poor durability against light and heat.

[0007] On the other hand, silicone resins are known as resins that are said to have high transparency and optically excellent properties and are also excellent in durability to light, and have, for example, oxygen permeability. Rubber-like polydimethylsiloxane is applied to special applications such as contact lenses and variable focus lenses, and these are difficult to apply to general optical elements such as lenses and prisms that require mechanical strength. It was. On the other hand, in recent years, an optical element using a silicone-based optical resin having a ladder-type silsesquioxane skeleton has been proposed (for example, see Patent Document 2). For example, the optical element using light at around 400 nm is used. The heat resistance is still inadequate to be applied to, and the optical durability of light is high! /, And plastic optical element materials satisfying the heat resistance are still available! .

Patent Document 1: JP 2002-105131 A

Patent Document 2: Japanese Patent Laid-Open No. 2004-354547

Disclosure of the invention

Problems to be solved by the invention

[0008] An object of the present invention is to provide a plastic optical element material capable of improving light stability, excellent transparency, and maintaining its characteristics over a long period of time, and a plastic optical element using the same (hereinafter referred to as a plastic optical element) It is also simply referred to as an optical element), and to provide an optical pickup device having good pickup characteristics using the same.

Means for solving the problem

[0009] The above object of the present invention can be achieved by the following configurations.

[0010] 1. At least one kind of caged silsesquioxane having a reactive group, at least one kind of inorganic fine particles having a reactive group, and at least a polyfunctional compound having two or more reactive groups A plastic optical element material, which is a resin composition comprising a polymer obtained by copolymerizing a mixture of one kind. [0011] 2. consists structural units said cage silsesquioxane O hexane is represented by T ⁿ structure (the following general formula (1)) and D ^m structure (following one general formula (2)), the following general these 2. The plastic optical element material as described in 1 above, which is a compound composed of a structural unit represented by the formula (3), wherein the compound has at least one reactive group.

[0012] General formula (1) R'Si COH) O

3-n n / 2

General formula (2) (R ² ) Si (OH) O

2 2-m m / 2

(In the formula, n represents an integer of 1 to 3, m represents an integer of 1 or 2. R ¹ and R ² represent a hydrogen atom and a substituent, and at least one of the substituents represents a reactive group. )

General formula (3) T ³ T ¹ D °

P q r

(In the formula, T represents the number of siloxane bonds for Si is 3, D represents the number of siloxane bonds for Si is 2. 1 is an integer of 1, 2 and o is 1, 2 is an integer, p is an integer from 4 to 20, q, r is an integer from 0 to 20, and p + q + 6.)

3. Said 1 or 2 characterized in that said caged silsesquioxane has a reactive group selected from a bur group, a (meth) attalyloyl group, an epoxy group, an oxetanyl group and a mercapto group. Plastic optical element material.

[0013] 4. The inorganic fine particles having a reactive group are inorganic oxides, and have a reactive group selected from a bur group, a (meth) acryloyl group, an epoxy group, an oxetanyl group, and a mercapto group. 4. The plastic optical element material according to any one of 1 to 3, which is characterized by the above.

[0014] 5. A plastic optical, characterized in that the plastic optical element material according to any one of the above !! to 4 is used, and a predetermined fine structure is provided on at least one optical surface. element.

[0015] 6. The light transmittance at a wavelength of 400 nm of a molded article having a thickness of 3 mm formed using the plastic optical element material according to any one of the above 1 to 4 is 85% or more. Plastic optical element.

[0016] 7. The plastic optical element as described in 5 or 6 above, which is used in a light collecting device having a light collecting function.

[0017] 8. An optical pick-up device that performs at least information reproduction and / or recording on an optical information recording medium, the light source emitting light, and the light emitted from the light source Information An optical element unit that performs at least one of irradiation of the recording medium and condensing of light reflected by the optical information recording medium, and the optical element unit according to any one of 5 to 7 above. An optical pickup device comprising a plastic optical element.

[0018] 9. The optical pickup device as described in 8 above, wherein the light source emits light having a wavelength of 390 to 420 nm.

The invention's effect

[0019] According to the present invention, a plastic optical element material capable of improving light stability, excellent transparency, and maintaining its characteristics over a long period of time, a plastic optical element using the same, and the same We were able to provide an optical pickup device with good pickup characteristics using

Brief Description of Drawings

FIG. 1 is a side view schematically showing an optical pickup device 1 according to the present invention.

FIG. 2 is a sectional side view of the objective lens 10 according to the present invention.

FIG. 3 is a sectional side view of an objective lens 10a according to the present invention.

FIG. 4 is a sectional side view of an objective lens 10b according to the present invention.

FIG. 5 is a sectional side view of an objective lens 10c according to the present invention.

FIG. 6 is a sectional side view of an objective lens 10d according to the present invention.

FIG. 7 is a sectional side view of a hologram optical element 10e and an objective lens 10f according to the present invention. Explanation of symbols

[0021] 1 Optical pickup device

2 Light source

3 Collimator lens

4 optical axis

5 Optical information recording media

6 Information recording surface

7 Polarizing beam splitter

8 Detector

10, 10a, 10b, 10c, 10d, lOf objective lenses (plastic optical elements, objective optics) element)

11, l la, l ld, 12d, 22b optical surface

20, 20a, 20b, 20c, 20d Optical path difference providing structure

21 First annular lens surface (annular lens surface)

22 Second annular lens surface (annular lens surface)

23 Third annular lens surface (annular lens surface)

23b Ring-shaped convex part

BEST MODE FOR CARRYING OUT THE INVENTION

[0022] The present invention will be described in more detail.

[0023] The plastic optical element material applied to the optical element in the invention according to any one of claims [4] to [4] includes a cage-like silsesquioxane having a reactive group, an inorganic fine particle having a reactive group, and It is a resin composition comprising a polymer obtained by copolymerizing a mixture composed of a polyfunctional compound.

[0024] Although the cage-like silsesquioxane (polymer) is highly transparent and its structure is rigid, its linear expansion coefficient is large and heat resistant compared to other thermoplastic optical resins such as polycarbonate. It was inferior. On the other hand, an optical element manufactured using a polymer obtained by copolymerizing a mixture of a caged silsesquioxane having a reactive group, inorganic fine particles having a reactive group, and a polyfunctional compound. Has high light transmittance, and has a high stabilizing effect against light irradiation. For example, even when continuously irradiated with light having a short wavelength of around 400 nm, white turbidity and fluctuations in refractive index can be suppressed. In addition, for example, it has been found that the deformation of the optical surface in a high temperature environment around 85 ° C. can be suppressed for a long time. In other words, it was found that the optical stability and thermal stability of the optical element can be improved, and an element capable of maintaining the characteristics for a long time can be manufactured.

[0025] According to the invention described in claim 5, at least one optical surface is provided with a predetermined fine structure, and this optical element is any one of claims 1-4, Since it is molded using the described plastic optical element material, it has high shape stability against environmental fluctuations such as light and heat, and appropriately suppresses deformation of the microstructure. That's the power S. [0026] According to the invention described in claim 6, a molded body having a thickness of 3 mm molded using the plastic optical element material of the present invention has high shape stability and has a high energy wavelength of 4 OOnm. Even if light in the vicinity is transmitted, it is possible to suppress the occurrence of white turbidity, refractive index fluctuation or deformation in the molded body. As a result, the light transmittance near the wavelength of 400 nm can be increased to 85% or more. Therefore, for example, it can be suitably used as an optical element for an optical information recording medium having a high information density such as a Blu-ray Disc.

[0027] According to the invention described in claim 7, even if an optical element is used in a condensing device having a condensing function, the optical element has high shape stability. There is no such thing as degrading characteristics. That is, even when high energy is given to the optical element by light collection, the high shape stability of the optical element makes it possible to suppress deformation of the optical element over a long period of time. This is the power to prevent the deterioration of the optical characteristics.

[0028] According to the invention described in claim 8, a mixture of a caged silsesquioxane having a reactive group, inorganic fine particles having a reactive group, and a polyfunctional compound is copolymerized. Since it is an optical element manufactured using the plastic optical element material of the present invention which is a resin composition containing the obtained polymer, the stabilization effect against light irradiation is high. For example, irradiation with light having a short wavelength around 400 nm Even with continuous exposure, the cloudiness and refractive index fluctuation are suppressed.

[0029] Further, for example, the deformation of the optical surface in a high temperature environment of around 85 ° C can be suppressed for a long time. That is, the light stability of the optical element can be improved, and the characteristics can be maintained for a long time. Therefore, for example, information can be read from and written to optical information recording media having a high information density, such as Blu-ray Discs, with good pick-up characteristics over a long period of time, making it a reliable optical pickup device. High quality! / You can get things S.

[0030] According to the invention of claim 9, the wavelength of the light emitted from the light source is 390 to 420 nm. That is, for example, even when light in a range of 390 to 420 nm corresponding to an optical information recording medium having a high information density such as a Blu-ray Disc is transmitted, the resin applied to the optical element in the present invention. The composition comprises a caged silsesquioxa compound having a reactive group. And a resin composition containing a polymer obtained by co-polymerizing a mixture of inorganic fine particles having a reactive group and a polyfunctional compound. Deterioration of the optical element can be prevented. As a result, the lifetime of the optical element can be extended, and a highly reliable optical pickup device can be obtained.

[0031] The plastic optical element material applied to the plastic optical element of the present invention comprises a mixture comprising a cage-like silsesquioxane having a reactive group, inorganic fine particles having a reactive group, and a polyfunctional compound. It is a resin composition containing a polymer obtained by copolymerization. In general, optical materials made of plastic have a larger coefficient of thermal expansion than inorganic materials such as glass and ceramics, so that the change in the shape of the element is a major problem in applications used in high-temperature environments.

[0032] On the other hand, as a result of diligent investigations to solve the above problems, the present inventors have used the above-described plastic optical element material of the present invention, so that, for example, even in a high temperature environment of around 85 ° C, It was found that the deformation of the surface can be suppressed for a long time. In addition, for example, the heat of optical elements that have a high stabilization effect against light irradiation, such as maintaining transparency and suppressing white turbidity and fluctuations in refractive index even when continuously irradiated with light having a short wavelength of around 400 nm. It has been found that it is possible to improve the stability and light stability and to manufacture an element capable of maintaining the characteristics for a long time.

[0033] (Silted Silsesquioxane)

The caged silsesquioxane used in the present invention will be described. Silsesquioxane is also called T-resin, and ordinary silica is represented by the formula of (SiO 2), while synesquioxane (also called polysilsesquioxane) is a compound represented by (RSiO 2). so

3/2

There are usually tetraalkoxysilanes (Si (OR ')) represented by tetraethoxysilane.

Four

(RSi (OR ')) compounds in which one alkoxy group is replaced with an alkyl group or an aryl group

Polysiloxane synthesized by hydrolysis and polycondensation of three products. As the molecular arrangement, amorphous, ladder, and cage (condensation cage) are known.

[0034] The cage silsesquioxane is specifically represented by a chemical formula of T ³ : (RSiO 2).

8 3/2 8

Type ((3) — 1), T ³ : (RSiO) Type represented by chemical formula ((3) — 2), T ³ : (RSi

10 3/2 10 12

O) The type represented by the chemical formula ((3) —3), T ³ : The type represented by the chemical formula (RSiO) Type ((3) -4, (3) -5) and: (RSiO) represented by the chemical formula ((3) -6, (

16 3/2 16

3) —7) etc. are known. Both of these are represented by n = 3 in the general formula (1), that is, they are made only from the T ³ structure.

[Chemical 1]

(3)-

{3} ~ 2

(3) -3

[Chemical 2] (3) 4

(3) ―o (3)

[0037] These are forces called perfect condensation cages. In addition, in general formula (3), a type called incomplete condensation cage where q ≠ 0 or r ≠ 0 is also known. In the invention, compounds of V and deviation types can also be used. Specific examples of types called incomplete condensation cages include the type represented by T ³ T ² ((3) -8), the type represented by T ³ Τ¾ ² ((

6 2 6

3) -9) and T ³ D ² type ((3) -10).

6 2

[0038] For Τ ³ Τ ^2, there are six Τ ³ structures in the general formula (1), and η =

6 2

It consists represented i.e. T ² structure 2 are two and, for Τ ³ Τ¾ ^2, wherein the T ³ structure 6,

6

One Τ ² structure and m = 2 in the general formula (2), that is, one D ² structure Furthermore, T ³ D ² consists of T ³ structural forces and ² D ² structures.

6 2

[0039] [Chemical 3]

[0040] In general formula (3) representing a caged silsesquioxane,! / Indicates a structural unit composed of general formula (1), and general formula (2)

Examples of the substituent represented by R ² include a hydrogen atom, a methylol group, an ethyl group, a cyclopentyl group, a cyclohexyl group, an isopropyl group, a 2-ethylhexyl group, a t-butyl group, and a 2-chloroethyl group. Group, methacryloxypropyl group, allyl group, 3-amaminopropyl group, 3-mercaptopropyl group, 3-glycidoxypropyl group and other aralkyl groups, phenyl group, 1-naphthyl group, 2-naphthyl group, phenanthryl group, etc. An aromatic group such as an aryl group, or a reactive group such as a (meth) atallyloyl group, an epoxy group, an oxetanyl group, or a mercapto group, and at least one of the cage structures contains the reactive group.

[0041] These cage silsesquioxanes may be used in combination of two or more kinds in the resin composition.

[0042] (Inorganic fine particles having a reactive group)

Examples of the inorganic fine particles used in the present invention include inorganic oxide fine particles, Specifically, for example, titanium oxide, zinc oxide, aluminum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, yttrium oxide, lanthanum oxide, cerium oxide, Phosphate formed in combination with oxides such as indium oxide, tin oxide, lead oxide, and double oxides such as lithium niobate, potassium niobate, and lithium tantalate , Stone) It is possible to mention nitrates and the like.

[0043] Since these inorganic fine particles are present in a state dispersed in a resin, when applying a plastic optical element material containing them to an optical element, the average particle diameter is not less than Inm in order to ensure transparency. 50 nm or less is preferable. More preferably, it is Inm or more and 30 nm or less, or more preferably Inm or more and 20 nm or less, and most preferably Inm or more and l Onm or less. If the average particle size is less than S Inm, it is difficult to disperse the inorganic fine particles at the time of manufacture, so that the desired performance may not be obtained. If the average particle size exceeds 50 nm, the resulting plastic optical element material Transparency may decrease due to turbidity and the light transmittance may be less than 70%. The average particle diameter here refers to the diameter when converted to a sphere having the same volume as the particle.

[0044] The shape of the inorganic fine particles is not particularly limited, but spherical fine particles are preferably used. Further, the particle size distribution is not particularly limited, but those having a relatively narrow distribution are preferably used rather than those having a wide distribution.

[0045] The inorganic fine particles used in the present invention are prepared by mixing a silane coupling agent having a reactive group such as a bur group, a (meth) atalyloyl group, an epoxy group, an oxetanyl group, or a mercapto group with an inorganic fine particle. It is an inorganic fine particle in which a reactive group is introduced by hydrolyzing and bonding the both, and this is reacted and cured in a mixed composition of a caged silsesquioxane and a polyfunctional compound in a resin. It is possible to secure the transparency of the cured resin by dispersing it evenly.

[0046] Examples of the silane coupling agent to be used include butyltrioxysilane, vinylenotrichlorosilane, butyltrimethoxysilane, butyltriethoxysilane, and γ-mercapto. Silane etc. are mentioned.

[0047] These inorganic fine particles may be used in combination of two or more kinds in the resin composition.

[0048] (Polyfunctional compound)

Examples of the polyfunctional compound used in the present invention include a compound having two or more reactive groups such as a bur group, a (meth) atalyloyl group, an epoxy group, an oxetanyl group, a mercapto group, and the like. It reacts with oxan and inorganic fine particles having a reactive group to form a crosslinked structure in the resin.

[0049] For example, as a polyfunctional (meth) atalylate, there are two or more (meth) atalyloyl groups, a ethylene glycolonoresimethacrylate, an ethyleneglyconoresimethacrylate, a tetraethylene glycol diatalate, a diethyleneglycolidialate, Trimethylol propanto tritalylate, trimethylol propane trimetatalylate, pentaerythritol tetraatalylate, pentaerythritol tetrametatalylate, etc. Bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, resorci Daricidyl ether type epoxy resin such as Nol diglycidyl ester, Diglycidino estenole phthalate and Diglycidino estenole dimer, Triglycid Noreethenoretriphenylmethane, tetraglycidyl ether tetraphenylethane, bisphenol S diglysidinoreatenore, crezonorenovolac glycidinoreatenore, triglycidinoreisocyanurate, tetrabromobisphenol A diglycidyl Ether isotropic S, as polyfunctional oxetane compound, reaction product of polyfunctional phenolic compound and oxetane lanthanide, for example, bisphenol A type, bisphenol F type, bisphenol S type, biphenyl type, force type And bifunctional oxetane compounds such as trisphenol methane type, trisphenol methane type and tris-resole methane type, and polyfunctional oxetane compounds such as phenol nopolac type, cresol nopolac type, and force-xarane type.

[0050] These polyfunctional compounds may be used in combination of two or more kinds in the resin composition.

[0051] (Stabilizer) In the plastic optical element material of the present invention, one or more stabilizers selected from hindered amine stabilizers, phenol stabilizers, phosphorus stabilizers, and thio stabilizers may be additionally added. By appropriately selecting these stabilizers and adding them to the plastic optical element material, for example, it is possible to enhance optical characteristics fluctuations such as white turbidity and refractive index fluctuations when continuously irradiated with light of a short wavelength such as 400 nm. Can be suppressed.

[0052] As a preferred phenol-based stabilizer, conventionally known ones can be used. For example, 2-tert-butylinole 6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylenophenyl phenyl acrylate, 2,4 di 1-tamyl 6- (1- (3,5 di-tert-amyl 2-hydroxyphenyl) ethyl) phenyl acrylate, etc., disclosed in JP-A 63-179953 is disclosed in JP 1-168643 Atarylate compounds: Octadecyl-3- (3,5 di-tert-butyl-4-hydroxyphenol) propionate, 2,2'-methylenebis (

4 methyl 6-t butylphenol), 1, 1, 3 tris (2 methyl 4 hydroxy — 5-t butylphenyl) butane, 1, 3, 5 trimethinole 2, 4, 6 tris (3, 5 di-tert-butyl 4- Hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ', 5'-di-tert-butyl-hydroxyphenylpropionate) methane) [ie pentaerythrmethyl-tetrakis (3- (3,5-di-tert-butyl-4) Alkyl-substituted phenolic compounds such as 3-hydroxyphenylpropionate))], triethylene glycol bis (3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate); 6- (4-hydroxy 3,5 g t-Butylanilino) 2, 4 Bisoctylthio 1, 3, 5 Triazine, 4 Bisoctylthio 1, 3, 5 Triazine, 2 Octylthio 4, 6 Bis (3,

5-di-t-butyl-4-oxyanilino) -1-triazine group-containing phenolic compounds such as 1,3,5-triazine and the like.

[0053] Preferred hindered amine stabilizers include bis (2, 2, 6, 6 tetramethyl-4-piperidyl) sebacate, bis (2, 2, 6, 6 tetramethyl-4-piperidyl) succinate, bis (1 , 2, 2, 6, 6 Pentamethyl-4-piperidyl) sebacate, bis (N oxytoxyl 2, 2, 6, 6 tetramethyl-4-piperidyl) sebacate, bis (N benzyloxy 2, 2, 6, 6 tetramethyl-4-piperidyl) sebacate, Bis (N-cyclohexyloxy 2, 2, 6, 6-tetramethyl-4-piperidyl) sebacate, bis (1, 2, 2, 6, 6 Pentamethyl 4-piperidinole) 2— (3,5 di-t-butyl 4-hydroxybenzenole) 2 Butyl malonate, bis (1-acroyl-2,2,6,6 Tetramethyl-4-piperidinole) 2,2 Bis (3,5 Di-tert-butyl-4-hydroxybenzyl) -2 butyl malonate, bis (1,2,2,6,6 pentamethyl-4-piperidyldecanoate), 2,2,6,6 tetramethyl-4-piperidylmetatalylate, 4 [3-((3,5 di-tert-butyl-4-hydroxyphenenole) propionyloxy]]-1 [2- (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy) ethyl] -2 , 2, 6, 6 tetramethylpiperidine, 2methyl-2- (2,2,6,6 tetramethyl-4-piperidyl) amino-N- (2,2,6,6 tetramethyl-4-piperidyl) propionamide, and the like.

[0054] Further, the preferred phosphorus stabilizer is not particularly limited as long as it is usually used in the general resin industry. For example, triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite. Huyte, Tris (Noyulfeninore) phosphite, Tris (Dinoyurfeninole) phosphite, Tris (2,4 di-t-butylphenol) phosphite, 1 0— (3,5 Di-tert-butyl-4-hydroxybenzyl) 9 , 10 Dihydro-9-oxa 10 Phosphaphenanthrene 10 Monophosphite compounds such as oxide; 4, A 'Butylidenebis (3-methyl 6-t butylphenyl-di-tridecyl phosphite), 4, 4' — Isopropi Redenbis (phenyldialkyl (C 1 -C 6) phosphite)

12 15

And diphosphite compounds such as Among these, tris (noyulphenyl) phosphite, tris (dinoylphenyl) phosphite, tris (2,4 di-tert-butylphenyl) phosphite and the like, which are preferable for monophosphite compounds, are particularly preferable.

[0055] In addition, preferable thio stabilizers include, for example, dilauryl 3,3 thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3-thiodipropionate, lauryl stearyl 3,3-thio Examples include dipropionate, pentaerythritol-tetrakis (/ 3 laurylthio monopropionate), 3,9 bis (2 dodecylthioethyl) 2,4,8,10-tetraoxaspiro [5,5] undecane.

[0056] The amount of these stabilizers is appropriately selected within a range not to impair the purpose of the present invention, but is usually 0.0; 100 to 2 parts by mass, preferably 0 to 100 parts by mass of the resin composition. 01 ～；! Mass part. [0057] (Surfactant)

A surfactant is a compound having a hydrophilic group and a hydrophobic group in the same molecule. The surfactant prevents white turbidity of the plastic optical element material by adjusting the rate of moisture adhesion to the resin surface and the evaporation rate of moisture from the surface.

[0058] Specific examples of the hydrophilic group of the surfactant include a hydroxyalkyl group having 1 or more carbon atoms, a hydroxyl group, a carbonyl group, an ester group, an amino group, an amide group, an ammonium salt, a phenol, and a sulfonate. , Phosphates, polyalkylene glycol groups and the like. Here, the amino group may be any of primary, secondary, and tertiary. Specific examples of the hydrophobic group of the surfactant include an alkyl group having 6 or more carbon atoms, a silyl group having an alkyl group having 6 or more carbon atoms, and a fluoroalkyl group having 6 or more carbon atoms. Here, the alkyl group having 6 or more carbon atoms may have an aromatic ring as a substituent. Specific examples of the alkyl group include hexyl, heptyl, octyl, noninole, decyl, undecenyl, dodecyl, tridecinole, tetradecyl, myristyl, stearyl, lauryl, normityl, cyclohexyl and the like. Examples of the aromatic ring include a phenyl group. This surfactant may have two or more groups as long as it has at least one hydrophilic group and one hydrophobic group as described above in the same molecule.

[0059] Specific examples of such surfactants include myristyl diethanolamine, 2-hydroxyethyl-2-hydroxydodecylamine, 2-hydroxyethyl-2-hydroxytridecylamine, 2 —Hydroxyethyl-2-hydroxytetradecylamine, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, di-2-hydroxyethyl-2-hydroxydodecylamine, alkyl (carbon Examples thereof include benzyl dimethyl ammonium chloride, ethylene bisalkyl (carbon number 8 to 18) amide, stearyl diethanolamide, lauryl diethanolamide, myristyl jetanol amide, palmityl diethanolamide, and the like. Of these, amine compounds or amide compounds having a hydroxyalkyl group are preferably used. In the present invention, two or more of these compounds may be used in combination.

[0060] The surfactant is added in an amount of 0.01 to 10 parts by mass with respect to 100 parts by mass of the plastic optical element material. When the amount of surfactant added is less than 0.01 parts by mass, temperature and humidity fluctuations It is impossible to effectively suppress the cloudiness of the molded product. On the other hand, when the addition amount exceeds 10 parts by mass, the light transmittance of the molded product becomes low, making it difficult to apply to an optical pickup device. The addition amount of the surfactant is preferably S to be 0.05 to 5 parts by mass with respect to 100 parts by mass of the resin composition S, more preferably 0.3 to 3 parts by mass.

[0061] (Plastic optical element material curing molding method)

The resin composition used in the present invention can be cured by any of ultraviolet and electron beam irradiation, heat treatment, or the like, and the cage silsesquioxane, the inorganic fine particles, and the multifunctional compound are mixed. It is obtained by mixing in an uncured state, and further preparing and curing a resin composition to which additives such as stabilizers and surfactants are added as necessary. The addition amount of the cage silsesquioxane is preferably 10 to 90 parts by mass, more preferably 20 to 70 parts by mass with respect to 100 parts by mass of the resin composition. The addition amount of the inorganic fine particles is preferably 10 to 50 parts by mass, more preferably 5 to 70 parts by mass with respect to 100 parts by mass of the resin composition. The addition amount of the polyfunctional compound is preferably 5 to 80 parts by mass, more preferably 10 to 60 parts by mass with respect to 100 parts by mass of the resin composition.

[0062] In preparing the resin composition before curing, an appropriate method can be employed. For example, when the properties of the resin composition to be prepared are liquid, each component is blended in a predetermined amount. It is possible to obtain a liquid curable resin composition by dissolving and mixing later, or uniformly mixing with a mixer, a blender, etc., and then heat-kneading with a second roll or the like, and a resin composition to be prepared In the case of solid, after mixing each component in a predetermined amount, it is dissolved and mixed, or after uniformly mixing with a mixer, a blender, etc. and then heat-kneaded with a kneader tool, etc., after cooling and solidifying Crushing to obtain a solid resin composition.

[0063] As a method for curing the resin composition, when the resin composition is ultraviolet and electron beam curable, a resin obtained by adding a photopolymerization initiator to a light-transmitting mold having a predetermined shape as necessary What is necessary is just to harden by filling with a composition or apply | coating on a board | substrate, and irradiating an ultraviolet-ray and an electron beam.

[0064] Examples of the photopolymerization initiator used here include acetophenone and acetophenone. Zirketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenenoreacetophenone, xanthone, funole lenon, benzanoldehydr, funole ren, anthraquinone, triphenylamine, carbazole, 3-Methylacetophenone, 4-Chronobenzophenone, 4, A'-Dimethoxybenzophenone, 4, A'-Diaminobenzophenone, Michler's ketone, Benzoinpropinoreethenore, Benzoinetinoreethenole, Penzinoresimethinoreketal Photo-radical initiators such as 1- (4-isopropylphenyl) 2-hydroxy-1-2-methylpropane 1-one, 2-hydroxy-2-methyl-1-phenylpropane 1-one, and the like.

[0065] On the other hand, when the resin composition is thermosetting, a resin composition to which a thermal polymerization initiator such as a thermal radical generator is added as necessary is prepared, and then compression molding, transfer molding, injection molding is performed. The thermosetting molding can be performed by the above. Examples of the thermal polymerization initiator used here include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4 dimethylvalero nitrinole), 2,2'-azobis (4-methoxy-). 2, 4 dimethylvaleronitrile) and other azo compounds, benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1, 1 'bis (t-butylperoxy) cyclohexane, etc. And the like.

[0066] (Optical pickup device)

Next, the plastic optical element and the optical pickup device of the present invention will be described with reference to FIG. 1 and FIG.

[0067] The optical pickup device 1 of the present invention includes a current DVD (hereinafter referred to as current DVD) that applies light having a wavelength of 650 nm, a so-called next-generation DVD (hereinafter referred to as next-generation DVD) that applies light having a wavelength of 405 nm. This is a device for reproducing and recording information on two types of optical information recording media 5.

The optical pickup device 1 passes laser light (light) emitted from a light source 2 through a single lens optical element such as a collimator lens 3 and an objective lens (plastic optical element) 10 having a fine structure described later, A light collecting spot is formed by collecting on the information recording surface 6 of the optical information recording medium 5 on the optical axis 4, and the reflected light from the information recording surface 6 is taken in by the deflecting beam splitter 7, and the beam is again applied to the light receiving surface of the detector 8. A spot is formed. [0069] The light source 2 includes a laser diode, and is configured to be able to select and emit light of two types of wavelengths of 650 nm and 405 nm by a known switching method.

[0070] The collimator lens 3, the objective lens (plastic optical element) 10, and the deflection beam splitter 7 constitute an optical element unit.

[0071] The objective lens 10 according to the present invention is an optical element having a fine structure, and is produced by molding a resin composition by injection molding. As shown in FIG. 2, the objective lens 10 is a single-sided optical element having a double-sided aspheric surface, and is predetermined for predetermined light passing through the optical surface 11 on one (light source side) optical surface 11 thereof. It has an optical path difference providing structure 20 (fine structure) that provides an optical path difference.

[0072] The optical path difference providing structure 20 includes three annular lens surfaces with the optical surface 11 centered on the optical axis 4 (hereinafter, the first annular lens surface 21, the second annular lens surface 22, The three annular lens surfaces 2;! 23 of the adjacent annular lens surfaces 2;! 23 have different refractive powers.

[0073] The first annular lens surface 21 and the third annular lens surface 23 are on the same optical surface 11, and the second annular lens surface 22 is a surface translated from the optical surface 11! / RU

[0074] The first annular lens surface 21 transmits light having both wavelengths of 650 nm and 405 nm, and the second annular lens surface 22 transmits light having a wavelength of 650 nm corresponding to the current DVD and the third annular lens surface. The surface 23 passes light with a wavelength of 405 nm corresponding to the next-generation DVD. The light that has passed through each annular lens surface 2;! 23 is condensed at the same position on the information recording surface 6.

In FIG. 2, the first annular lens surface 21 and the third annular lens surface 23 have a force S provided on the same optical surface 11, and the first and third annular lens surfaces 21. The second annular lens surface 22 does not have to be provided on the same optical surface as 23, and the second annular lens surface 22 is a surface translated from the optical surface 11; Further, the number of the three annular lens surfaces 2123 may be five or at least three.

[0076] Due to the action of the optical path difference providing structure 20 formed in this way, the objective lens 10 has the information recording surface 6 of the light emitted from the light source 2 with respect to a plurality of types of optical information recording media 5 such as the current DVD next-generation DVD. And the light reflected from the information recording surface 6 toward the detector 8 is highly concentrated. Can be performed with high reliability. In addition, since the resin composition forming the objective lens 10 has a high light transmittance of 85% or more, the above-described light collection can be performed with high efficiency. Therefore, since the power consumption of the light source 2 can be reduced, the power consumption of the entire optical pickup device 1 can be reduced.

Note that the objective lens 10 according to the present invention is not limited to the one having the optical path difference providing structure 20 described above. For example, the objective lens 10a having the optical path difference providing structures 20a to 20d shown in FIGS. Good as 10e.

[0078] The optical path difference providing structure 20a in Fig. 3 includes a plurality of diffraction ring zones 21a with the optical axis 4 as the center, the cross sections of the plurality of diffraction ring zones 21a are serrated, and each of the diffraction ring zones 21a The optical surface 11a is a discontinuous surface. The plurality of diffraction ring zones 21a are formed to increase in thickness as they move away from the optical axis 4. The objective lens 10a shown in FIG. 3 is a so-called diffractive lens.

The optical path difference providing structure 20b in FIG. 4 has a plurality of annular recesses 21b that cause a phase difference around the optical axis 4 in a concentric manner. The ring-shaped concave portions 21b are formed on each of the optical surfaces l ib centered on the optical axis 4 (on the upper and lower optical surfaces centering on the optical axis 4 in FIG. 4). Adjacent ring-shaped recesses 21b are continuously integrated with each other, and the entire cross-section of each ring-shaped recess 21b is stepped. In addition, the optical surface 22b that forms each annular zone-shaped recess 21b is a surface that is translated with respect to the optical surface l ib. The objective lens 10b shown in FIG. 4 is a so-called phase difference lens.

[0080] In Fig. 4, the adjacent annular recesses 21b are continuous and integrated, and the entire cross section is stepped. However, the annular recess 21b is simply formed on the optical surface l ib. They may be provided individually (in this case, for example, the structure is the same as that of the objective lens 10 shown in FIG. 2). Further, in FIG. 4, the force that the annular zone-shaped concave portion 21b has a concentric shape, as shown in FIG. 5, the objective lens 10c having the annular zone-shaped convex portion 23b on the third annular zone-shaped lens surface 23 of FIG. (In FIG. 5, the same components as those in FIG. 2 are denoted by the same reference numerals).

The optical path difference providing structure 20d in FIG. 6 is composed of a plurality of diffraction ring zones 21d with the optical axis 4 as the center, the cross sections of the plurality of diffraction ring zones 21d are sawtooth-shaped, and each of the diffraction ring zones 21d The optical surface 1 Id is a discontinuous surface. The cross section of each diffraction ring zone 21d is 3 steps 22d along the optical axis direction. The optical surface 12d of each step 22d is a discontinuous surface and is a surface orthogonal to the optical axis 4.

[0082] It should be noted that the lens 10d shown in FIG. 6 includes, for example, a hologram optical element (HOE) 10e having an optical path difference providing structure 20d similar to FIG. 6 and an objective lens 1 Of as shown in FIG. It may be configured. In this case, the hologram optical element 10e uses a flat optical element, and the optical path difference providing structure 20d is provided on the surface of the objective lens 10f of the optical element.

Note that the optical pickup device 1 may perform information reproduction and recording on, for example, three types of optical information recording media 5 of a CD, a current DVD, and a next-generation DVD. The combination of the optical information recording medium 5 for reproducing and recording information with the optical pickup device 1 is a design matter and is appropriately set.

Example

Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

[0085] (Production Example 1)

0. 027 mol of disodium hydrogen phosphate containing 3 L, 3.53 mol of aluminum sulfate aqueous solution and 7.06 mol of disodium hydrogen phosphate aqueous solution 2 L each Added over a minute. During the microparticle formation, the pH was controlled at 3.0 using sulfuric acid, and the temperature was controlled at 30 ° C. After the addition, soluble salts were desalted and removed by ultrafiltration to obtain a 10% by mass aluminum phosphate dispersion. To 100 parts by mass of this dispersion, 300 parts by mass of methanol and a 1 mol% nitric acid aqueous solution were added. While stirring this solution at 50 ° C., a mixed solution of 100 parts by mass of methanol and 6 parts by mass of γ-methacryloxypropyltrimethoxysilane was added over 60 minutes, and then the mixture was further stirred for 2 hours. The obtained transparent dispersion was suspended in ethyl acetate and centrifuged to obtain a white fine powder. According to observation, this powder had an average particle size of about 20 nm. This was designated as inorganic fine particles A.

[0086] (Production Example 2)

300 parts by mass of methanol and 1 mol% nitric acid aqueous solution were added to 5 parts by mass of aluminum oxide C (average particle size of about 13 nm) manufactured by Nippon Aerosil Co., Ltd. While stirring this solution at 50 ° C, 100 parts by mass of methanol and 6 parts by mass of γ-methacryloxypropyltrimethoxysilane The mixture was added over 60 minutes and then stirred for another 2 hours. The obtained transparent dispersion was suspended in ethyl acetate and centrifuged to obtain a white fine powder. According to TEM observation, this powder had an average particle size of about 15 nm. This was designated as inorganic fine particles B.

[0087] (Production Example 3)

A white fine powder was obtained in the same manner as in Production Example 2, except that cyclopentyltrimethoxysilane was used instead of γ-methacryloxypropyltrimethoxysilane. According to observation, this powder had an average particle size of about 18 nm. This was designated as inorganic fine particles C; having reactive groups! /, N! /, Inorganic fine particles.

[0088] Examples;! To 5, comparative examples;! To 5

According to the blending composition shown in Table 1, each raw material was mixed and then kneaded using a kneader to obtain a uniform thermosetting resin composition. Each of the obtained resin compositions was filled in a mold having dimensions of 30 mm × 30 mm × 3 mm, and then heated and pressed at 220 ° C. for 20 minutes to obtain a plate-like plastic optical element.

[0089] [Table 1]

JP2007 / 071629

贓翁 (s)

[0090] In Table 1, details of each component other than the inorganic fine particles are as follows.

[0091] Soil-like silsesquioxane A: Methacryl— P〇SS ™ (Sigma Aldrich f

Soil-like silsesquioxane B: Methacryl 1 Isobutyl 1 POS S ¹

(Made by company)

Saddle Silsesquioxane C: Octacyclohexvl— POSS ™ (with reactive groups V, rod-shaped silsesquioxane, manufactured by Sigma-Aldrich)

Multifunctional compound A: Pentaerythritol tetratalylate

Multifunctional compound B: Trimethylolpropane trimetatalylate

Polymerization initiator: Azobisisoptyronitrile

Stabilizer A: Tetrakis (1, 2, 2, 6, 6-pentamethylpiperidyl) butanetetracarboxylate

Stabilizer Β: 2, 2'-Methylenebis (4,6-di-tert-butylphenyl) -2-ethyl hexyl phosphite

Surfactant: Pentaerythritol distearate.

[0092] Next, the optical properties of the plastic optical elements obtained in Examples;! To 5 and Comparative Examples 1 to 5 were evaluated based on the following method. The results are shown in Table 2. .

[Evaluation of Plastic Optical Element]

(Colorability and transparency evaluation)

About the said plastic optical element, the light transmittance by wavelength 400nm was measured, the color tone through the transmitted light was visually observed, and coloring property and transparency were evaluated. As a result, each optical element made of plastic had a light transmittance of 86% or more and a high transmittance.

[0094] (Evaluation of light durability)

Using the optical pickup device shown in Fig. 1 in a constant temperature and humidity chamber at 90 ° C and 55% RH, light with a wavelength of 405 nm is emitted from the laser diode of the light source 2 onto each plastic optical element with a diameter of lmm. After continuous irradiation for 1500 hours as a circular spot light, the laser irradiation spot was visually observed and, according to the following criteria, (1) transparency due to cloudiness (coloration), (2) shape stability. And evaluated.

[0095] (1) Coloring degree

◯: Slight turbidity is observed at the laser irradiated spot after continuous irradiation

Δ: After continuous irradiation, turbidity is observed at the laser irradiation point

X: After continuous irradiation, white turbidity is observed at the laser irradiation point

If it is more than Δ, it is in a practically acceptable range.

[0096] (2) Shape stability ○: After continuous irradiation, slight deformation is observed at the laser irradiation point

Δ: After continuous irradiation, slight deformation is observed at the laser irradiation point

X: Deformation is observed in the laser irradiated area after continuous irradiation

If it is more than Δ, it is in a practically acceptable range.

[Table 2]

[0098] As shown in Table 2, the molded product molded using the resin composition according to the present invention does not cause coloring or white turbidity even when continuously irradiated with short-wavelength light for a long time, and further deforms. High shape stability could be maintained.

[0099] Example 6

An optical element (objective lens) having the same composition as that of the plastic optical element described in Examples 1 to 5 and having the configuration described in FIGS. 2 to 7 was produced by injection molding. Each optical pickup device was fabricated with the structure described. Next, using each optical pickup device, recording and reproduction on DVD were performed using light of a wavelength of 405 nm by a laser diode.

[0100] Comparative Example 6

An optical element was produced in the same manner as in Example 6 with the same composition as the plastic optical element described in Comparative Examples 1 to 5, and recorded on and reproduced from a DVD in the same manner.

[0101] (Evaluation)

The optical pickup device using the optical element of Example 6 showed good pickup characteristics with no deformation or the like even after continuous irradiation for a long time. On the other hand, the optical element of Comparative Example 6 When using, the smaller the optical surface structure is, the more deformed (complex) it is, the more deformation occurs, and the pickup characteristics decline.

Claims

The scope of the claims

[1] At least one kind of caged silsesquioxane having a reactive group, at least one kind of inorganic fine particles having a reactive group, and at least one kind of a polyfunctional compound having two or more reactive groups A plastic optical element material, which is a resin composition comprising a polymer obtained by copolymerizing a mixture comprising:

[2] The cage silsesquioxane has a T ⁿ structure (the following general formula (1)) and a D ^m structure (the following general formula

(2) a compound composed of the structural unit represented by) and composed of the structural unit represented by the following general formula (3), and having at least one reactive group in the compound 2. The plastic optical element material according to claim 1, wherein

General formula (1) R'Si COH) O

3-n n / 2

General formula (2) (R ² ) Si (OH) O

2 2-m m / 2

General formula (3) T ³ T ¹ D °

P q r

[3] The cage-like silsesquioxane has a reactive group selected from a bur group, a (meth) atalyloyl group, an epoxy group, an oxetanyl group, and a mercapto group. 3. The plastic optical element material according to item 2.

[4] The inorganic fine particles having a reactive group are inorganic oxides, and have a reactive group selected from a bur group, a (meth) attayl group, an epoxy group, an oxetanyl group, and a mercapto group. The plastic optical element material according to any one of claims 1 to 3, wherein the plastic optical element material according to claim 1 is characterized.

[5] A plastic optical element material according to any one of claims 1 to 4, wherein a predetermined fine structure is provided on at least one optical surface. Stick optical element.

[6] The plastic optical element material according to any one of claims 1 to 4 is used. A plastic optical element characterized in that a 3 mm-thick molded article has a light transmittance of 85% or more at a wavelength of 400 nm.

[7] The plastic optical element according to [5] or [6], which is used in a light collecting device having a light collecting function.

[8] An optical pickup device that performs at least one of reproducing and recording of information on an optical information recording medium, the light source emitting light, and the light emitted from the light source to the optical information recording medium An optical element unit that performs at least one of irradiation of light and condensing of light reflected by the optical information recording medium, and the optical element unit is any one of claims 5 to 7, 1 An optical pick-up device comprising the plastic optical element described in the above item.

9. The optical pickup device according to claim 8, wherein the light source emits light having a wavelength of 390 to 420 nm.