JPH06347616A - Light diffusing body - Google Patents

Abstract

PURPOSE:To provide a light diffusing body suppressing the diffusion of light in the reverse direction to the direction of light propagation, mainly diffusing the light only in the direction of light propagation and optically controlled by composing the body of a transparent body having the specified distribution of refractive index. CONSTITUTION:A light diffusing body is composed of a transparent body having the specified distribution of refractive index. Namely, the difference DELTAn between the maximum value and the minimum value of the refractive index is >=0.005 and the difference of the refractive index at two arbitrary points 500Angstrom apart is <=0.01 or <=DELTAn/2. The average of the refractive index within a circle of 5mm in diameter at an arbitrary position is nearly equal to the average of the whole refractive index. The material of the transparent body is suitably a transparent solid body and capable of substantially continuing the refractive index and e.g. it is a glass, transparent polymer or resin composition. Consequently, the discontinuous part of refractive index within the light diffusing body is removed and the reflection of light in the reverse direction is prevented.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light diffuser.
is there. More specifically, the light traveling in the direction opposite to the traveling direction of the light
Suppresses diffusion and diffuses light mainly in the direction of light travel
It relates to a light-controlled light diffuser. [0002] Generally, a transparent material is provided with a light diffusing property.
As a method, white pigment such as titanium oxide or calcium carbonate
Inorganic transparent crystal fine particles such as glass, glass fine particles, transparent high content
Dispersing light diffusing agents such as fine particles in a transparent material in a sea-island shape
It is known how to do this, such as lighting covers and projections.
TV screen, or surface display with uniform brightness
It has been used in various applications such as optical devices. From the viewpoint of energy saving and functionality in recent years,
Suppresses the backward diffusion of the incident light and allows the light to travel.
There is a demand for a light diffuser that diffuses greatly in the direction
There is. For such light controlled light diffusers,
Difference in refractive index between diffusing agent and transparent material, and particle size of light diffusing agent
Is known as a light diffuser that is characterized by being within a specific range
Is. For example, in Japanese Patent Publication No. 60-21662, a transparent
Refractive index is 0.01-0.1 smaller than bright resin and average
A transparent material powder having a particle size of 1 to 10 μm was dispersed.
A light diffusing resin is shown. Also, Japanese Patent Laid-Open No. 02-6557
In the report, the difference in refractive index between the light diffuser and the transparent plastic
Is 0.02 to 0.04, and the particle size of the light diffusing agent is
Light diffusing plastics that are 7-30 μm are shown
It Furthermore, in JP-A-63-205602, a transparent resin and a light diffusion
Ratio of refractive index of the agent, particle size of the light diffusing agent, and addition of the light diffusing agent
Depending on the effective projected area and the invalid projected area determined from the weight
A defined light diffuser is shown. On the other hand, a light diffusing agent having a specific composition is used.
Light diffusers are also disclosed. For example, Japanese Patent Publication 01-539
No. 01 publication describes methyl methacrylate-based polymers as well.
Aromatic vinyl monomers, alkyl groups with 1-8 carbon atoms
Alkyl acrylate, alkyl group having 1 to 4 carbon atoms
Suspension polymerization of alkyl acrylate and crosslinkable monomer
Particle size obtained by 10 to 500 μm, gel content 40 to
Do not disperse 90% by weight of crosslinked particles having a swelling degree of 3 to 25.
A light diffusing acrylic resin is shown. In addition,
No. 01-172801 discloses an organic group having an affinity with a transparent resin.
Solid state with a polysiloxane structure in which is attached to a silicon atom
The number average particle size of the silicone resin is 0.3 to 10 μm.
A light diffusing plate using spherical particles of m as a light diffusing agent is shown.
ing. Besides, two or more kinds of light diffusing agents are used in combination.
Light diffusers are also disclosed. For example, JP-A-63-291001
In the publication, the difference in refractive index from the transparent resin is 0.001.
~ 0.08, average particle size 20 ~ 80μm crosslinked organic polymer
The difference in refractive index between the particles of 2 to 20% by weight and the transparent resin is 0.
02-0.1, cross-linked organic polymer having an average particle size of 2-20 μm
-A light diffuser with 0.1-5% by weight of particles is shown
ing. [0006] However, these
All of the conventional light diffusers of
The light is refracted by using the step of the refractive index generated at the boundary of the agent.
Diffuses forward, but this step in the refractive index is
Since it reflects the part, it also diffuses the light in the opposite direction. That
Therefore, the conventional light diffuser suppresses the backward light diffusion, and
In principle, there is a limit to how much light can be diffused in the traveling direction.
It Therefore, the object of the present invention is to reverse such light in the opposite direction.
By preventing reflection and bending the path of light, conventional light
Providing a light diffuser with light controllability that exceeds the limit of the diffuser
It is to be. [0007] That is, the present invention is a refraction
The difference Δn between the maximum value and the minimum value of the rate is 0.005 or more, 500
Å The difference in refractive index between two arbitrary points is 0.01 or less, or
Δn / 2 or less and within a circle of 5 mm in diameter at any position
The average of the indices of refraction of
A light diffuser made of a transparent material having a refractive index distribution of
It is provided. Odor in the transparent body forming the light diffuser of the present invention
The difference between the maximum and minimum refractive index is 0.005 or more
Is desirable. If it is too small, the light travels
The diffusion in the direction is small and the light diffusivity is insufficient. [0009] In addition, any of the transparent body within 500 Å
The difference in refractive index between two points is 0.01 or less, or the difference in refractive index
Is 1/2 or less. If it is too big,
The change in the refractive index is remarkable, and the step of the refractive index is substantially generated.
Reflection in the opposite direction occurs. Further, refraction within a circle of 5 mm in diameter at an arbitrary position
The average of the indices is approximately equal to the average of the overall indices of refraction.
It has a refractive index distribution. This is
The parts with different folding ratios are
It shows that they are uniformly dispersed. Difference in refractive index
If the uneven part is unevenly distributed, it resembles a prism or lens.
In addition, it exhibits optical transparency and non-uniform light diffusion. The light diffuser in the present invention, that is, the transparent body
The material is not particularly limited, but it is transparent and has a substantially constant refractive index.
It is not particularly limited as long as it is a solid that can be continued, for example,
Examples thereof include glass, transparent polymers and resin compositions. Since
Below, the polymer or resin composition as the material of the light diffuser of the present invention.
An example will be described. In other words, the transparency with a refractive index distribution
The clear body is composed of two or more transparent polymers with different refractive indexes.
It consists of dispersions, with continuous refractive index at their boundaries.
And the composition of such polymers and resins.
It is a light diffuser consisting of things. As a more specific example, the homopolymer is
Radical Polymerizable Monomers Constituting Polymers with Different Refractive Index
Which is a transparent polymer composed of two or more components of
Single component of two components with a difference in refractive index of 0.005 or more in the body
I is one of the monomers in the body and j is the other
And the reactivity ratio of i to j is r _ij > 1,
Reactivity ratio r of j to i _ji Two-component monomer with <1
Refractive index obtained by radical polymerization of a monomer mixture containing
There are light diffusers that are transparent polymers with a distribution. Radical polymerizable monomers that can be used here
The polymer obtained is selected from among those that are transparent.
It Specifically, styrene, o-methylstyrene, m-
Methylstyrene, p-methylstyrene, p-methoxys
Ethylene, p-ethylstyrene, o-chlorostyrene, etc.
Styrene and styrene derivatives; methyl methacrylate, methyl
Ethyl tacrylate, propyl methacrylate, methacryl
Acid n-butyl, isobutyl methacrylate, methacrylic acid
n-octyl, n-dodecyl methacrylate, methacryl
Acid-2-ethylhexyl, stearyl methacrylate,
Cyclohexyl tacrylate, phenyl methacrylate,
Methacrylic acid esters such as benzyl tacrylate;
Methyl phosphate, ethyl acrylate, n-butyl acrylate
, Isobutyl acrylate, propyl acrylate, ac
Octyl acrylate, Dodecyl acrylate, Steric acrylate
Allyl, 2-chloroethyl acrylate, Fe-acrylate
Acrylic esters such as nil and benzyl acrylate;
Acrylonitrile, methacrylonitrile, vinyl acetate,
From vinylic monomers such as acrylamide and maleimides
To be elected. Refractive index of homopolymer of only these monomers
Are described in various publications. For example, POLYMER HAND
BOOK third edition (Polymer Handbook 3rd edition)
Refractive Indices of Polyme on pages VI / 451-VI / 462
rs (Refractive Indices of Polymer
)) Section. Two components are selected from these monomers.
First of all, among the monomers of two or more components selected,
The difference in refractive index of the polymers obtained by polymerizing each of them is 0.
It is different by 005 or more. Moreover, the two components
There is a difference in the polymerization reactivity of each component when the monomers are copolymerized.
It is something. When the difference in refractive index is smaller than 0.005,
A light diffuser showing sufficient light diffusivity cannot be obtained. Then, a polymer which gives a polymer having a high refractive index is obtained.
A monomer and a monomer that gives the polymer having a low refractive index
Reaction of i to j, where one is i and the other is j
Sex ratio r _ij > 1 and r _ji Select the one that is <1
combine. The reactivity ratio r _ij Is (reaction between i
Rate constant) / (reaction rate constant of i with respect to j),
r _ji And (reaction rate constant between j) / (j to i
Reaction rate constant). If it is reactive as described above,
At the beginning of the polymerization, the monomer i is preferentially polymerized,
The composition changed continuously because the monomer j was polymerized.
A polymer is obtained. On the other hand, r _ij <1, and r _ji <1
Is a random copolymer having a uniform refractive index,
Does not show light diffusion. Also, r _ij > 1, and r _ji > 1
At this time, the homopolymers of each are dispersed non-uniformly.
The composition becomes discontinuous at the interface of, and light is reflected in the opposite direction.
It is not desirable because it will be shot. In addition, these monomers
The reactivity ratio is based on the POLYMER HANDBOOK third edition (polymer
-Handbook Third Edition) II / 153 pages of Free Radical
copolymerization Reactivity Ratio
・ Copolymerization / reactivity ratio)
II / Page 267 Q and e Volues for Free Radical co
polymerizationsof Vinyl Monomers and Telogens
T & e values for free radical
Copolymarizations of Vinyl Monomers
And telogens) can be calculated. In addition to the above two components, another type of monomer is used.
However, the resulting polymer is
Choose one that does not impair the specified refractive index distribution in the invention.
Yes. In polymerizing the above radically polymerizable monomer
Or the well-known polymerization method of adding an oil-soluble polymerization initiator
Applicable. As an oil-soluble polymerization initiator, organic peroxide or
Or an azo compound can be used.
Ropyl peroxydicarbonate, t-butyl peroxy
Ci-2-ethylhexanoate, t-butylperoxy
Pivalate, lauroyl peroxide, benzoyl peroxide
-Oxide, t-butyl peroxybenzoate,
Examples include zobisisobutyronitrile.
One or a mixture of these can be used. Oil soluble
The amount of the polymerizable polymerization initiator used may be a commonly used amount.
It may be 5 parts by weight or less with respect to 100 parts by weight of the body. Here, the polymerization method is as follows:
If there is suspension polymerization. In bulk polymerization, light spreading of the desired shape
It is convenient to do it in a mold that can mold the powder. Suspended weight
The polymer obtained by the above procedure was removed by a well-known post-treatment operation.
Protrusion, this is also the desired shape by well-known injection molding and extrusion molding
The light diffuser may be molded. Another light composed of the transparent polymer of the present invention
As a diffuser, transparent polymer particles with a uniform refractive index
The child has at least 0.005 or more different refractive index
A radically polymerizable monomer that gives a polymer
Particles obtained by impregnating them together and polymerizing them are
Transparent polymerization with a refractive index almost equal to that of the outermost part of the child
A transparent resin group having a refractive index distribution that is uniformly dispersed in the body
There is a light diffuser consisting of a product. Transparent polymer particles having a uniform refractive index
Is prepared by subjecting the radical-polymerizable monomer to the well-known suspension polymerization.
It was obtained. As this radical polymerizable monomer
It is selected from the above-mentioned vinyl monomers. These vinyl single
The monomer may be used alone or in combination of two or more kinds.
it can. However, when using two or more types together,
It is desirable that they are compatible with each other. If necessary, the monomer may be used in one molecule.
A polyfunctional monomer having two or more radically polymerizable functional groups
In combination with the transparent polymer particles as a crosslinked structure
Good. The polyfunctional monomer may be a known one,
(Poly) ethylene glycol di (meth) acrylate,
(Poly) propylene glycol di (meth) acrylate
1,4-butanediol di (meth) acrylate,
1,6-hexanediol di (meth) acrylate,
Allyl (meth) acrylate, Allyl cinnamate, Divinyl ester
Bifunctional monomer such as benzene; trimethylolpropane tri
(Meth) acrylate, triallyl trimellitate,
Trifunctional monomers such as diallyl rainate; pentaerythritol
Tetra-functional monomers such as tetra- (meth) acrylate
Can be mentioned. In particular, they have different refractive indices as described below.
Impregnate transparent polymer particles with a monomer that gives a polymer
In order to prevent the polymer particles from dissolving,
Is desirable. At least 0.005 or more different refractive index
The radically polymerizable monomer that gives the polymer has
Selected from dical polymerizable monomers. This radical polymerizability
The monomer may be one component or two or more components. Choice
Refractive index of polymers obtained from radically polymerizable monomers
Does not give a different refractive index of 0.005 or more
And the change in the refractive index distribution of the obtained transparent resin composition is small.
In addition, when used as a light diffuser, the light diffusivity is insufficient. Further, in selecting the radically polymerizable monomer,
And the polymer is in phase with the transparent polymer particles to some extent.
It is desirable to have solubility. Therefore, the radical weight
Compose the transparent polymer particles as a component of the compatible monomer
It is convenient to include a part of the monomer component. The oil-soluble polymerization initiator is one that is usually used.
Often, the above-mentioned organic peroxides and azo compounds are used.
The amount of the polymerization initiator used is usually 100 parts by weight of the monomer.
0.1 to 5 parts by weight may be sufficient. The transparent polymer particles containing a polymerization initiator
To impregnate the monomer, dip it directly in the monomer
Or a method of dispersing both in an aqueous medium containing a suspension stabilizer
There are laws, etc. The immersion time is the same as that for the transparent polymer particles and the single polymer.
Generally about 5 to 100 minutes, depending on the affinity of the polymer.
Yes. If it is too long, the monomer is the transparent polymer particles.
Since it diffuses evenly inside the child, the change in the refractive index is small.
Therefore, the desired transparent polymer cannot be obtained. The monomer impregnated in the transparent polymer particles
Can be polymerized anyway. The polymerization method is
Water containing suspension stabilizers to prevent light polymer particles from coalescing
It suffices to disperse it in a volatile medium and polymerize it. The obtained polymer particles are directed from the center to the outer layer.
Once, the refractive index changed almost continuously. The refractive index obtained as described above is continuous.
A polymer particle that changes to
Dispersion in a transparent resin having almost the same refractive index
It can be a transparent polymer having a folding ratio distribution.
Can be molded to obtain a light diffuser having a desired shape. Here, the outermost refractive index of the particles is, for example,
Can be measured as. One is the
This is a method of observing particles under a polarizing microscope. Beckerai
Outside the particle at the position of the bright line along the particle outline called
The size of the refractive index of the shell and the immersion liquid is determined. Another person
Law is Applied Optics Vol.25, No19 1 October 1986
Pride Optics Vol. 25, No. 19, October 1, 1986)
Intraparticle refraction by the described shearing interferometry
It is a method of measuring the change in the refractive index and knowing the refractive index of the outermost part of the particle.
It The outermost refractive index of the polymer particles is almost equal to
A transparent resin having a refractive index means that the refractive index of the polymer is
The difference between the outermost refractive index of the particles is 0.01 or less, or
½ or less of the difference Δn between the maximum and minimum refractive index in the particle
Is what is. The difference in the refractive index of the polymer particles is 0.0
If 1 or more than 1/2 of Δn,
The difference in the refractive index that occurs at the particle interface cannot be ignored,
Reflection of light occurs, and the backward light diffusion becomes stronger, which is preferable.
No Polymer particles with continuously changing refractive index
As a method for dispersing the
Good. For example, both are Henschel mixer, tumbler
After mechanically mixing with a Bunbury mixer or a single shaft,
This is a method of melt-kneading with a twin-screw extruder. Or machine
After mechanically kneading, injection molding or hot press molding may be used.
Yes. In addition, the monomer that constitutes the transparent resin and its partial polymerization
The polymer particles are mixed with a syrup containing a body, cast polymerization, suspension
There is also a method of suspension polymerization. The amount of the polymer particles dispersed depends on the particles and the use.
Therefore, it varies, but generally 100 weight of transparent resin
It is 0.0001 to 100 parts by weight with respect to parts. Further, a light comprising the transparent resin composition of the present invention
As an example of the diffuser, a homopolymer has a refractive index of 0.00
Radical-polymerizable monomer 2 which constitutes 5 or more different polymers
Using more than one component, a homopolymer with a high refractive index should be used.
A monomer with a low refractive index in homopolymerization
Oil-soluble one of the constituent monomers (A)
Suspension polymerization in an aqueous medium using a polymerization initiator
The ratio of the other monomer (B) is substantially between 70-95%.
Add continuously, without adding a new polymerization initiator.
Polymer obtained by a polymerization method for continuing and completing
A particle has a refractive index that is approximately equal to the refractive index of the outermost part of the particle.
Has a refractive index distribution that is evenly dispersed in the transparent polymer
There is a light diffuser made of a transparent resin composition. Radical polymerizable monomer (A) and radical
The monomers applicable to the polymerizable monomer (B) are as described above.
You can choose from the vinyl monomers. However, the monomer
(A) and (B) are obtained by polymerizing separately.
It is a composition in which the difference in refractive index between polymers is 0.005 or more. The monomers (A) and (B) are different from each other.
You may use together a body. However, the monomer when used in combination
Random copolymer obtained from the group of (A) and the monomer
Difference in refractive index of random copolymer obtained from group (B)
Is used together so that it will be 0.005 or more.
It is necessary to choose a monomer. Use two or more types together
In this case, it is desirable that they are compatible with each other. Further, the monomers (A) and (B) are required
Two or more radically polymerizable functional groups are included in one molecule depending on
You may use together the polyfunctional monomer. With the polyfunctional monomer
As described above, a well-known one may be used. Addition of the monomer (B) in this polymerization method
The amount added is 1/3 to 3 times the amount of the monomer (A).
It The amount of the monomer (B) is 1/3 times that of the monomer (A).
When it is full, the change in the refractive index in the resulting polymer particles is small.
In addition, the light diffusivity when used as a light diffuser is not sufficient. Also
If it is 3 times or more, it becomes difficult to finish the polymerization. The monomers (A) and (B) are respectively
Polymers that are polymerized separately and have some compatibility
Is more desirable. As an example thereof, the monomer
To select (A) and (B), one is a homopolymer,
Make the other a copolymer containing the monomer units
Or both polymers, copolymers containing the same monomer units
And the amount of two or more monomers that make up those copolymers
Select the monomers (A) and (B) to give different ratios
To do. Specifically, styrene (monomer) is used as the monomer (A).
Refractive index of homopolymer is 1.59) and styrene as the monomer (B)
And methyl methacrylate (refractive index of homopolymer 1.49)
Combination of mixed monomers; or as the monomer (A)
Mainly styrene, mixed with a small amount of methyl methacrylate
The main body is methyl methacrylate as the monomer (B).
Body, a combination of styrene as a small amount of mixed monomer, etc.
It The oil-soluble initiator used in this polymerization method is also described above.
Well known for the polymerization of radically polymerizable monomers such as
Therefore, one kind or two or more kinds are used. this
The amount of the polymerization initiator used is a monomer or a mixture of monomers.
Use 0.02 to 2 parts by weight per 100 parts by weight. The oil soluble
The sex initiator has been previously dissolved in the monomer (A).
May be added separately to the aqueous medium and mixed.
Yes. The aqueous medium in this polymerization method is
It is used for slow suspension polymerization.
It is an aqueous solution containing a suspension aid. Suspension stabilizers and
As the suspension aid, one suitable for the monomer used may be used.
Well-known ones are selected. Also, these suspension stable
The agent and suspension aid are usually charged before the start of polymerization, but if necessary,
And a part of them may be added appropriately during the polymerization. The temperature condition for the polymerization is about 60 to 120 ° C.
The temperature may be any temperature suitable for the polymerization initiator used. Stirring conditions
Is a normal suspension polymerization suitable for the monomer used,
Known conditions may be used for the production of As a device,
Well-known stirring blades such as turbine blades, Faudler blades, professional blades
Heavy equipped with stirrer with propeller blades, blue margin blades, etc.
It is best to use a combined container and attach a baffle to the container.
It is general. In the present polymerization method, the monomer (A) is first prepared.
Suspension polymerize. And the polymerization rate is 70-95%
When it reaches, the addition of the monomer (B) is started. The
Before adding the monomer (B), the monomer
Suspension polymerization was carried out only with (A), and the polymerization time and polymerization rate
Due to excessive and exothermic behavior, the time when the polymerization rate becomes 70 to 95%
Make sure. The polymerization rate of the monomer (A) does not reach 70%.
When the addition of the monomer (B) is started at
Most of (B) consists of the monomer (A) and its polymer
Since the particles permeate inside the particles almost uniformly, the bending inside the particles
It becomes polymer particles with a substantially uniform folding rate and becomes a light diffuser.
The light diffusivity at the time of doing is insufficient. The polymerization rate is 9
When the amount exceeds 5%, the addition of the monomer (B) is started.
And the diffusion of the monomer (B) into the polymer particles is reduced.
Therefore, there was a portion in the particle where the refractive index changed rapidly.
The polymerization initiator is deactivated and the polymerization does not proceed sufficiently.
Become. For the polymerization of the monomer (B), a new radical was added.
No polymerization initiator is added. That is, in the monomer (B)
Does not include a radical polymerization initiator, and radical polymerization
No additional initiator is added. For the polymerization of the monomer (B),
When a radical polymerization initiator is newly added, the monomer (B)
A polymer that forms only polymer particles and has a refractive index distribution
This is because particles are hard to form. The monomer (B) is added substantially continuously.
It Here, the substantially continuous addition means that the monomer and the polymer are added.
The polymerization should be such that about 5-30% monomer is present in the mixture.
It may be supplied according to the progress, so-called continuous supply
Alternatively, it may be supplied intermittently. After the addition of the polymerizable monomer (B) is completed, it remains
Polymerization is continued until all the remaining monomers are exhausted. After completion of polymerization
The polymer by a well-known solid-liquid separation method, and
Then, it is further washed, dehydrated and dried. The refractive index obtained as described above is continuous.
A polymer particle that changes to
Dispersion in a transparent resin having almost the same refractive index
A transparent resin composition having a folding ratio distribution can be obtained.
It can be molded to obtain the desired shape of the light diffuser
It This method has already been described above. According to the present invention, the refractive index of the light diffuser
By virtually eliminating discontinuities, the direction of light travel
Greatly diffuses light, and greatly diffuses light backwards
Can be reduced. The light diffuser of the present invention is used as an illumination cover.
For applications such as projectors and projection TV screens
With this, light can be diffused efficiently. EXAMPLES The present invention will be specifically described with reference to examples.
However, the present invention is not limited thereto.
The refractive index distribution in the examples is applied optics.
By the method described in Vol. 25, No. 19, Carl-Zeiss
Using a differential interference microscope, Interphako
It was measured. The polymer particle size is Leeds & Northrup
Light diffractive scattering particle size measuring device (Microtra
FRA) and expressed as a volume average. Also for press molding
Is an ASF type hydraulic press machine manufactured by Shindo Metal Industry Co., Ltd.
Using. The total light transmittance and haze value of the obtained light diffusion plate are
Poic type integrating sphere type haze maker manufactured by this precision optics company
It was measured with a target. Example 1 40 parts by weight of methyl methacrylate, vinyl phenyl ac
Benzoyl peroxide 0.2 in 10 parts by weight of relate
5 parts by weight, 0.075 parts by weight of n-butyl mercaptan
In addition, between two 200 x 200 mm stainless steel plates
Add a gasket with a thickness of 3 mm along the periphery of the
Pour 143 cc into a clean mold and water at 70 ° C.
Polymerize in a bath for 16 hours, then heat at 80 ° C for 8 hours
Processed. After cooling, open the frame and obtain a light diffusion plate with a thickness of 3 mm.
It was In the obtained light diffusion plate, the maximum value of the refractive index is 1.
57, minimum is 1.49, refraction between two points 500 Å apart
The maximum value of the rate difference was 0.004. Other evaluation results
It shows in Table 1. In addition, the yield of the polymer of methylmethacrylate
Folding rate is 1.49, vinyl phenyl acrylate
The polymer has a refractive index of 1.567. And meth
Rumethacrylate vinyl acrylate
Reactivity ratio is 22.7, vinyl phenyl acrylate
The reactivity ratio of methyl methacrylate to methyl methacrylate is 0.00
It is 5. Example 2 In Example 1, vinylphenyl acrylate was blended with vinyl chloride.
In the same manner as in Example 1 except that rubenzoate was used,
A light diffusion plate having a thickness of 3 mm was obtained. The obtained light diffuser odor
The maximum refractive index is 1.58 and the minimum is 1.49, 5
The maximum value of the difference in refractive index between two points separated by 00Å is 0.002.
there were. Other evaluation results are shown in Table 1. In addition, vinyl vinyl
The refractive index of the Nzoate polymer is 1.58. That
The vinyl benzoate of methyl methacrylate
Reactivity ratio is 8.30, Methyl vinyl benzoate
The reactivity ratio for methacrylate is 0.05. Comparative Example 1 In Example 1, vinylphenyl acrylate was added to
In the same manner as in Example 1 except that the thickness of the 3 mm thick
A light diffuser plate was obtained. In the obtained light diffuser, the refractive index
The maximum was almost uniform at 1.512. Other
The evaluation results are shown in Table 1. In addition, refraction of styrene polymer
The rate is 1.59. And methyl methacrylate
The reactivity ratio of styrene to styrene is 0.46.
The reactivity ratio for methyl methacrylate is 0.52.
is there. Example 3 A glass container equipped with a stirrer and having an internal volume of 1 liter had 0.01 weight.
Charge 500 g of polyvinyl alcohol aqueous solution of the amount%,
Dissolve 0.02g benzoyl peroxide in this
Benzyl methacrylate 10g in a microsyringe
Strictly drop 0.5 μl of each to remove the monomer particles.
Stir at 40 rpm to prevent coalescence and breakage
And polymerized at 70 ° C. for 18 hours. After cooling, washing, dehydration,
Polymer dried and having a particle size of 450 μm and a refractive index of 1.57
The particles were obtained. 0.005 g of benzoyl peroxide
In 2.5 g of methyl methacrylate containing
0.004 g of benzyl methacrylate polymer particles are light
Soak for 5 minutes at 35 ° C with shaking, then
200 g of 0.05% by weight polyvinyl alcohol water solution
The liquid is stirred at 400 rpm.
Put in a glass container with a stirrer and polymerize at 60 ° C for 18 hours.
did. After cooling, wash, dehydrate, and dry, and circulate from the center of the particle.
Polymer particles whose refractive index decreases continuously toward the edges
(A) was obtained. The outermost particles of the obtained polymer particles (A) are
Refractive index is 1.56, central refractive index is 1.57, 500
Å The maximum value of the change in refractive index at a distance of 0.00000
It was 4. Glass container with an agitator having an internal volume of 5 liters
Deionized water 2500g, polymethacrylic acid sodium
0.65 g of aluminum and 7.5 g of disodium hydrogen phosphate are charged.
And a styrene containing 20 g of benzoyl peroxide.
Monomer 1300g, methyl methacrylate 700g
And disperse while stirring at 1300 rpm,
Polymerize at 5 ° C for 150 minutes, then dehydrate, wash and dry.
To obtain polymer particles having a refractive index of 1.566. (This is
Trick resin (D). ) 100 weight of the obtained matrix resin (D)
And 15 parts by weight of polymer particles (A) are mixed in a mixer.
After that, press molding was performed at 190 ° C. to obtain a plate having a thickness of 3 mm.
The obtained plate was evaluated. The results are shown in Table 1. Example 4 Production of Matrix Resin (D) in Example 3
Then, instead of 1300g of styrene, weighed 1160g.
Other than 840 g instead of 700 g of lumethacrylate
In the same manner, polymer particles having a refractive index of 1.552 were obtained.
(This is referred to as matrix resin (E).)
The same procedure as in Example 3 is performed after using the epoxy resin (E).
It was The evaluation results are shown in Table 1. Comparative Example 2 Production of Matrix Resin (D) in Example 3
, 900g instead of 1300g styrene, methyl
Other than 1100 g instead of 700 g of methacrylate
In the same manner, polymer particles having a refractive index of 1.542 were obtained.
(This is referred to as matrix resin (F).)
The same procedure as in Example 3 is performed after using the epoxy resin (F).
It was The evaluation results are shown in Table 1. Examples 5, 6 and Comparative Example 3 Ion exchange was carried out in a glass container equipped with a stirrer and having an internal volume of 5 liters.
Water 3500g, sodium polymethacrylate 0.88
g, and charged with disodium hydrogen phosphate 10.50 g
Later, styrene containing 5.0 g of benzoyl peroxide
500 g, ethylene glycol dimethacrylate 5.0
g of monomer was charged and dispersed with stirring at 800 rpm.
The temperature was raised to 85 ° C. to start polymerization. After 185 minutes
When the polymerization rate of 90% was reached,
200g, styrene 50g, ethylene glycol dime
Continuous mixture of 2.5 g of tacrylate over 110 minutes
Was added. After polymerizing for another 60 minutes, dehydration, washing and drying
It was dried to obtain polymer particles (B) having a particle size of 144 μm. The outermost particles of the obtained polymer particles (B) are
Refractive index is 1.56, central refractive index is 1.59,500
Å The maximum value of the refractive index change at a distant point is 0.00005
Met. 15 parts by weight of the obtained polymer particles (B),
Matrix used in Examples 3 and 4 and Comparative Example 2, respectively
Resin (D), (E), (F) 100 parts by weight
The same procedure as in Example 3 was performed. The evaluation results are shown in Table 1. Comparative Examples 4 to 6 Ion exchange was carried out in a glass container equipped with a stirrer and having an internal volume of 5 liters.
Water 3500g, sodium polymethacrylate 0.88
g, and charged with disodium hydrogen phosphate 10.50 g
Later, styrene containing 5.0 g of benzoyl peroxide
500 g, ethylene glycol dimethacrylate 5.0
g of monomer was charged and dispersed with stirring at 800 rpm.
And polymerize at 85 ° C for 230 minutes, then dehydrate, wash and dry.
Polymer particles dried and having a particle size of 287 μm and a refractive index of 1.59
(C) was obtained. 15 parts by weight of the obtained polymer particles (C)
And the matri used in Examples 3 and 4 and Comparative Example 2, respectively.
Resin (D), (E), (F) 100 parts by weight
The same procedure as in Example 3 was carried out. The evaluation results are shown in Table 1. [Table 1] Δn: difference between maximum and minimum values of refractive index δn: maximum value of refractive index difference between two points 500 Å apart

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masahiko Moriya             Sumitomo Chemical 5-1, Soukai-cho, Niihama-shi, Ehime             Industry Co., Ltd. (72) Inventor Akika Kanemitsu             Sumitomo Chemical 5-1, Soukai-cho, Niihama-shi, Ehime             Industry Co., Ltd.

Claims (1)

Claims: 1. The difference Δn between the maximum and minimum values of the refractive index is 0.0.
The difference in refractive index between any two points that are 05 or more and 500 Å apart is 0.01 or less, or Δn / 2 or less, and the average of the refractive indices within a circle of 5 mm in diameter at any position is the entire refractive index. A light diffuser comprising a transparent body having a refractive index profile that is approximately equal to the average of. 2. A transparent polymer having a refractive index distribution, which is composed of a dispersion of two or more transparent polymers having different refractive indexes, and the refractive index continuously changes at the boundary between them. Alternatively, the light diffuser according to [claim 1], which comprises a transparent resin composition. 3. A transparent polymer comprising a homopolymer having two or more components of radical-polymerizable monomers constituting polymers having different refractive indexes, wherein the difference in refractive index between homopolymers is 0.1. 0
The reactivity ratio of i to j is r _ij > 1, where i is one of the two component monomers having a ratio of 05 or more and j is the other, and j is Reactivity ratio r to i
The light diffuser according to claim 2, which is a transparent polymer having a refractive index distribution obtained by radical polymerization of a monomer mixture containing a two-component monomer having _ji <1 as a main component. 4. A transparent polymerizable polymer particle having a uniform refractive index is impregnated with a radical polymerizable monomer that gives a polymer having a refractive index different by at least 0.005 together with a polymerization initiator, A transparent resin composition having a refractive index distribution in which particles obtained by polymerization are uniformly dispersed in a transparent polymer having a refractive index substantially equal to the outermost refractive index of the particles. Diffuser. 5. A homopolymer comprising two or more components of radical-polymerizable monomers constituting a polymer having a refractive index different by 0.005 or more, and a homopolymer constituting a polymer having a high refractive index. And one of the monomers constituting the polymer having a low refractive index in the homopolymer (A) is suspension polymerized in an aqueous medium using an oil-soluble polymerization initiator, and the polymerization rate is Is 7
Polymer particles obtained by a polymerization method in which the other monomer (B) is added substantially continuously between 0 to 95%, and the polymerization is continued and completed without newly adding a polymerization initiator, The light diffuser according to claim 2, which comprises a transparent resin composition having a refractive index distribution uniformly dispersed in a transparent polymer having a refractive index substantially equal to the refractive index of the outermost portion of the particles.