JP4609047B2 - Light guide and method for manufacturing the same, surface light emitting device, display device, and lighting device - Google Patents

Description

The present invention relates to a light guide and a method for manufacturing the same , a surface light-emitting device, a display device , and an illumination device. More specifically, the present invention relates to a light guide made of a foam foamed by application of radiation energy and thermal energy, a method for manufacturing the same, and a surface light emitting device, a display device, and an illumination device using the light guide.

The light guide is an optical member that emits incident light in a direction different from the incident direction. The light guide is made of a translucent molded article, and a light output pattern that causes a change in refractive index is provided on the surface or inside thereof.
As a method for obtaining the light emission pattern, (1) a method of printing white dots on the surface, (2) a method of forming grooves and dots on the surface, and (3) a method of dispersing light scatterers inside are used. It has been.

The light scattering light guide using the method (3) is a light guide of a type in which incident light is scattered by an inherent light scatterer and guided to the light exit surface. Since there is no pattern processing on the surface of the light guide, a light diffusing sheet is not required and a member is saved compared to a printed light guide using the method (1) and a molded light guide using the method (2). There is merit that can be made. In addition, there is an advantage that the light guide can be reduced in weight by using a light scatterer having a small specific gravity.
Examples of the light scatterer include light scattering particles such as styrene fine particles described in Patent Document 1, silicon beads described in Patent Document 2, methacrylic fine particles described in Patent Document 3, and hollow beads described in Patent Document 4. For example, bubbles made of carbon dioxide described in Patent Document 5 are used.

When the light scattering light guide is used in a surface light emitting device, it is necessary to increase the light scattering property as the distance from the light source increases in order to emit uniform light from the light emitting surface. However, it is actually difficult to change the particle size and density distribution of the light scatterer. For this reason, the light scatterer is simply uniformly dispersed and formed into a wedge shape (with a taper angle) so that the entire light guide becomes thicker away from the light source.
On the other hand, a light guide has also been proposed in which hollow particles are dispersed so as to increase the hole diameter and density as the distance from the light source increases, thereby reducing luminance unevenness (Patent Document 6).

In order to prevent light leakage from the light-scattering light guide and increase the emission efficiency, it is necessary to cover the incident surface and other surfaces than the emission surface with a reflector. Furthermore, it is often necessary to provide another optical member such as a prism on the light exit surface of the light guide.
Therefore, in the conventional light scattering light guide, a light diffusion sheet is not necessary, but a plurality of optical members are used in combination. For example, a reflection sheet, a light guide plate, a prism, etc. It was stored repeatedly.
Japanese Patent Laid-Open No. 06-324215 JP-A-10-183532 JP-A-11-19928 JP 9-17221 A JP 11-291374 A Japanese Patent Laid-Open No. 06-324215

The light guide is mainly built in an edge light type surface emitting device. This edge light type surface light emitting device is used in general lighting equipment and display devices.
For example, in a liquid crystal display device, since the liquid crystal itself of the display element does not emit light, a display function is exhibited in combination with a surface light emitting device called an edge light type backlight or a front light. With the diversification of applications such as liquid crystal display devices, the quality items required for the light guide are becoming stricter.
In particular, space-saving and portability of display devices are emphasized, and LEDs used as light sources are downsized, so that light guides are strongly reduced in thickness and weight. Since the light guide occupies more than half of the thickness of the surface light emitting device, it contributes greatly to thinning. In addition, in order to improve display quality and save power, it is also required to improve light utilization efficiency.

However, in the case of a light guide in which light scatterers are simply uniformly dispersed, the entire light guide needs to be formed into a wedge shape as described above. Specifically, it will be molded by injection molding, but the thinner the mold, the worse the filling rate and transfer accuracy to the mold (because of the resin flow limit), so molding to a thickness of 1 mm or less It was difficult.
On the other hand, as in Patent Document 6, the light guide in which the hollow particles are dispersed so that the hole diameter and the density increase as the distance from the light source increases, it is also possible to form a flat plate, which makes it easy to reduce the thickness. It is considered to be. However, a specific dispersion method for creating such a hole diameter and density distribution has not been described, and there has been no method for actually manufacturing such a light guide.
Therefore, there is a limit to thinning the light scattering light guide.

  In addition, when the light scattering light guide is configured by stacking a reflection sheet, a light guide plate, a prism, etc. in a box-shaped housing, a gap is generated between the optical members only by storing the light scattering light guide. The leak could not be completely suppressed. For this reason, there has been a limit to improving the light utilization efficiency. Moreover, since it comprises using many members, there was also a problem in productivity.

  In light of the above circumstances, the present invention uses a light guide that achieves both improvement in light utilization efficiency and productivity improvement through thinning, integration and member saving, and a manufacturing method thereof, and such a light guide. It is an object to provide a surface light-emitting device, a display device, and a lighting device.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have formed a light guide body in which fine bubbles are inherently formed of a foam foamed by radiation energy and thermal energy, thereby reducing the thickness and reducing the number of members. And found that a light guide that can be integrated is obtained. That is, the present invention employs the following configuration.

[1] A step of applying radiation energy in a predetermined non-uniform distribution using a photomask to a foamable sheet (A) made of a foamable composition that foams upon application of radiation energy and thermal energy; A step of imparting radiation energy in a uniform distribution to the foamable sheet (B) comprising a foamable composition that foams upon application of thermal energy;
The foamable sheet (A) and the foamable sheet (B) after the application of radiation energy are heated and pressed, and the foamed sheet (A) is subjected to foaming while integrating the two. Is foamed so as to have a low foaming region of 0.5% or less and a high foaming region of 1% or more, and a light guide part is formed in part or all of the foamed sheet (B). A method for producing a light guide, wherein the light reflecting portion is foamed so that the occupied area ratio becomes 15% or more.
[2] A step of applying radiation energy in a predetermined non-uniform distribution using a photomask to a foamable sheet (A) made of a foamable composition that foams upon application of radiation energy and thermal energy, and application of radiation energy Subsequent heating and pressing the foamable sheet (A) and the prism sheet, and foaming the foamable sheet (A) while integrating the two, the foamable sheet (A) has a bubble occupation area ratio. Is produced so as to have a low foaming region of 0.5% or less and a high foaming region of 1% or more, and a light guide part is formed in a part or all of the light guide. Method.
[3] Applying radiation energy in a predetermined non-uniform distribution using a photomask to a foamable sheet (A) made of a foamable composition that foams upon application of radiation energy and thermal energy; A step of applying radiation energy in a uniform distribution to a foamable sheet (B) comprising a foamable composition that foams by application of thermal energy, a prism sheet, a foamable sheet (A) after application of radiation energy, and radiation energy; The foamable sheet (B) after application is heated and pressed in this order, and the foamable sheet (A) and the foamable sheet (B) are foamed while integrating the three, (A) is foamed so as to have a low foaming area with a bubble occupation area ratio of 0.5% or less and a high foaming area with 1% or more. Parts to form a light guide portion, the foamable sheet (B) a method for manufacturing a light guide, characterized in that a light reflecting portion by foaming as gas bubbles occupying area ratio of 15% or more.
[4] Application of radiation energy to the foamable sheet (A) was performed by covering a portion excluding at least part of the periphery of the foamable sheet (A) with a photomask, and not covering with the photomask. The method for manufacturing a light guide according to any one of [1] to [3], wherein a side surface on the peripheral side is foamed so that a bubble occupation area ratio is 15% or more, and a light reflecting portion is formed on the side surface. .
[5] Applying radiation energy in a predetermined non-uniform distribution using a photomask to a foamable sheet (A) made of a foamable composition that foams upon application of radiation energy and thermal energy, and application of radiation energy The subsequent foamable sheet (A) and the transparent sheet are heated and pressed, and the foamable sheet (A) is foamed while integrating the two. Is produced so as to have a low foaming area of 0.5% or less and a high foaming area of 1% or more.
[6] The foamable composition foamed by the application of radiation energy and thermal energy reacts with an acid generator or a base generator that generates an acid by the action of ray energy and reacts with the acid or base. The method for producing a light guide according to any one of [1] to [5], comprising a decomposable and foamable compound having a decomposable and foamable functional group that decomposes and desorbs at least one kind of low-boiling volatile substances.
[7] A light guide manufactured by the method for manufacturing a light guide according to any one of [1] to [6].
[8] the surface emitting device comprising a light guide according, and a light source [7].
[9] A display device comprising the surface light-emitting device according to [8].
[10] An illumination device comprising the surface light-emitting device according to [8].
Related.

  According to the present invention, a light guide body that achieves both improvement in light utilization efficiency and productivity improvement through thinning, integration and member saving, and a method for manufacturing the same, and a surface light emitting device using such a light guide body, A display device and a lighting device can be provided.

<Foaming composition>
(Type of foamable composition)
The foam constituting the light guide of the present invention is obtained by foaming a foamable composition by applying radiation energy and thermal energy.
Specific examples of such foamable compositions include (A) a photofoamable compound that generates a gas upon irradiation with light, and (B) a combination of a photopolymerizable compound and a thermally foamable compound (Patent 3422384). (C), (C) An acid generator that generates acid by the action of radiation energy or a base generator that generates a base, and reacts with the acid or base to decompose and desorb one or more low-boiling volatile substances. A foamable composition (see Japanese Patent Application Laid-Open No. 2004-2812).
In particular, the foamable composition (C) (hereinafter referred to as “composition (C)”) is preferable because the bubble diameter can be 10 μm or less and the bubble distribution pattern can be precisely controlled over a wide range.

The composition (C) is a composition that develops foamability by the action of radiation energy and thermal energy. The foamable composition contains at least the following two components.
One of them is an acid generator that generates an acid by the action of radiation energy or a base generator that generates a base. The other is a decomposable and foamable compound that reacts with the generated acid or base to decompose and desorb one or more low-boiling volatile compounds.

(Acid generator and base generator)
The acid generator or base generator used in the composition (C) is generally called a chemically amplified photoresist and a photoacid generator or photobase generator that is used for photocationic polymerization. Can be used.

As a suitable photoacid generator for the composition (C),
(1) Diazonium salt compounds (2) Ammonium salt compounds (3) Iodonium salt compounds (4) Sulfonium salt compounds (5) Oxonium salt compounds (6) Phosphonium salt compounds Mention may be made of PF ₆ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ and CF ₃ SO ₃ ^— salts of aliphatic onium compounds. Although the specific example is enumerated below, it is not limited to what was illustrated.

Bis (phenylsulfonyl) diazomethane,
Bis (cyclohexylsulfonyl) diazomethane,
Bis (tert-butylsulfonyl) diazomethane,
Bis (p-methylphenylsulfonyl) diazomethane,
Bis (4-chlorophenylsulfonyl) diazomethane,
Bis (p-tolylsulfonyl) diazomethane,
Bis (4-tert-butylphenylsulfonyl) diazomethane,
Bis (2,4-xylylsulfonyl) diazomethane,
Bis (cyclohexylsulfonyl) diazomethane,
Benzoylphenylsulfonyldiazomethane,

Trifluoromethanesulfonate,
Trimethylsulfonium trifluoromethanesulfonate,
Triphenylsulfonium trifluoromethanesulfonate,
Triphenylsulfonium hexafluoroantimonate,
2,4,6-trimethylphenyldiphenylsulfonium trifluoromethanesulfonate, p-tolyldiphenylsulfonium trifluoromethanesulfonate,
4-phenylthiophenyldiphenylsulfonium hexafluorophosphate,
4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate,
1- (2-naphthoylmethyl) thiolanium hexafluoroantimonate,
1- (2-naphthoylmethyl) thiolanium trifluoromethanesulfonate,
4-hydroxy-1-naphthyldimethylsulfonium hexafluoroantimonate,
4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate,
(2-oxo-1-cyclohexyl) (cyclohexyl) methylsulfonium trifluoromethanesulfonate,
(2-oxo-1-cyclohexyl) (2-norbornyl) methylsulfonium trifluoromethanesulfonate,
Diphenyl-4-methylphenylsulfonium perfluoromethanesulfonate,
Diphenyl-4-tert-butylphenylsulfonium perfluorooctanesulfonate,
Diphenyl-4-methoxyphenylsulfonium perfluorobutanesulfonate,

Diphenyl-4-methylphenylsulfonium tosylate,
Diphenyl-4-methoxyphenylsulfonium tosylate,
Diphenyl-4-isopropylphenylsulfonium tosylate

Diphenyliodonium,
Diphenyliodonium tosylate,
Diphenyliodonium chloride,
Diphenyliodonium hexafluoroarsenate,
Diphenyliodonium hexafluorophosphate,
Diphenyliodonium nitrate,
Diphenyliodonium perchlorate,
Diphenyliodonium trifluoromethanesulfonate,

Bis (methylphenyl) iodonium trifluoromethanesulfonate,
Bis (methylphenyl) iodonium tetrafluoroborate,
Bis (methylphenyl) iodonium hexafluorophosphate,
Bis (methylphenyl) iodonium hexafluoroantimonate,
Bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate,
Bis (4-tert-butylphenyl) iodonium hexafluorophosphate,
Bis (4-tert-butylphenyl) iodonium hexafluoroantimonate,
Bis (4-tert-butylphenyl) iodonium perfluorobutanesulfonate,

2-methyl-4,6-bis (trichloromethyl) -1,3,5-triazine,
2,4,6-tri (trichloromethyl) -1,3,5-triazine,
2-phenyl-4,6-ditrichloromethyl-1,3,5-triazine,
2- (p-methoxyphenyl) -4,6-ditrichloromethyl-1,3,5-triazine,
2-naphthyl-4,6-ditrichloromethyl-1,3,5-triazine,
2-biphenyl-4,6-ditrichloromethyl-1,3,5-triazine,
2- (4′-hydroxy-4-biphenyl) -4,6-ditrichloromethyl-1,3,5-triazine,
2- (4′-methyl-4-biphenyl) -4,6-ditrichloromethyl-1,3,5-triazine,
2- (p-methoxyphenylvinyl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-chlorophenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-methoxy-1-naphthyl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (benzo [d] [1,3] dioxolan-5-yl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (3,4,5-trimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (3,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (2,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (2-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-butoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,
2- (4-pentyloxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine,

2,6-di-tert-butyl-4-methylpyrylium trifluoromethanesulfonate,
Trimethyloxynium tetrafluoroborate,
Triethyloxynium tetrafluoroborate,
N-hydroxyphthalimide trifluoromethanesulfonate,
N-hydroxynaphthalimide trifluoromethanesulfonate,
(Α-benzoylbenzyl) p-toluenesulfonate,
(Β-benzoyl-β-hydroxyphenethyl) p-toluenesulfonate,
1,2,3-benzenetriyltrismethanesulfonate,
(2,6-dinitrobenzyl) p-toluenesulfonate,
(2-nitrobenzyl) p-toluenesulfonate,
(4-nitrobenzyl) p-toluenesulfonate,
Etc. Of these, iodonium salt compounds and sulfonium salt compounds are preferred.

  In addition to the onium compounds, sulfonates that generate sulfonic acid upon irradiation with active energy rays, such as 2-phenylsulfonylacetophenone, halides that generate hydrogen halide upon irradiation with active energy rays, such as phenyltribromo. Methylsulfone and 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethane, and ferrocenium compounds that generate phosphoric acid upon irradiation with active energy rays, such as bis (cyclopentadienyl) ferrocenium hexa Fluorophosphate, bis (benzyl) ferrocenium hexafluorophosphate, and the like can be used.

Furthermore, the following imide compound derivatives having acid generating ability can also be used.
N- (phenylsulfonyloxy) succinimide,
N- (trifluoromethylsulfonyloxy) succinimide,
N- (10-camphorsulfonyloxy) succinimide,
N- (trifluoromethylsulfonyloxy) phthalimide,
N- (trifluoromethylsulfonyloxy) -5-norbornene-2,3-dicarboximide,
N- (trifluoromethylsulfonyloxy) naphthalimide,
N- (10-camphorsulfonyloxy) naphthalimide.

As a suitable photobase generator for the composition (C),
(1) Oxime ester compounds (2) Ammonium compounds (3) Benzoin compounds (4) Dimethoxybenzylurethane compounds (5) Orthonitrobenzylurethane compounds Generates an amine. In addition, a base generator that generates ammonia or hydroxy ions by the action of light may be used. These include, for example, N- (2-nitropentyloxycarbonyl) piperidine, 1,3-bis [N- (2-nitrobenzyloxycarbonyl) -4-piperidyl] propane, N, N'-bis (2-nitrobenzyl). It can be selected from oxycarbonyl) dihexylamine, O-benzylcarbonyl-N- (1-phenylethylidene) hydroxylamine, and the like. Further, a compound that generates a base by heating may be used in combination with the photobase generator.

  In addition, a photosensitizer may be used in combination as appropriate in order to shift or expand the wavelength region of light energy activated by the photoacid generator or photobase generator. For example, examples of photosensitizers for onium salt compounds include acridine yellow, benzoflavin, and acridine orange.

  In order to minimize the amount of addition of the acid generator or base generator and the light energy while generating the necessary acid, an acid proliferator or base proliferator (K. Ichimura et al., Chemistry Letters, 551- 552 (1995), JP-A-8-248561, JP-A-2000-3302700) can be used together with an acid generator or a base generator. The acid proliferator is thermodynamically stable at around room temperature, but decomposes with acid and generates a strong acid by itself to greatly accelerate the acid-catalyzed reaction. By utilizing this reaction, it is possible to improve the generation efficiency of acid or base, and to control the foam generation rate and the foam structure.

(Decomposable foamable compound)
The decomposition foamable compound (hereinafter abbreviated as a decomposable compound) used in the composition (C) reacts with an acid or a base to decompose and desorb one or more low boiling point volatile substances (low boiling point volatile compounds). It is a compound.
The low boiling point means having a boiling point at which gasification is possible at the time of foaming, that is, a boiling point lower than the temperature at the time of foaming. The boiling point of the low-boiling volatile substance is usually 100 ° C. or lower, preferably room temperature or lower.
Examples of the low boiling point volatile substance include isobutene (boiling point: −7 ° C.), carbon dioxide (boiling point: −79 ° C.), nitrogen (boiling point: −196 ° C.), and the like.

The decomposable compound must be previously introduced with a degradable functional group capable of generating a low boiling point volatile substance.
Among the decomposable functional groups, those that react with acid include tert-butyloxy group represented by the structural formula of -O-tBu, tert-butyloxycarbonyl group represented by the structural formula of -CO-O-tBu,- Examples thereof include a tert-butyl carbonate group represented by the structural formula of O-CO-O-tBu, a keto acid, and a keto acid ester group. At this time, -tBu represents a -C (CH _{3) 3.}
By reacting with an acid, tert-butyloxy and tert-butyloxycarbonyl groups are isobutene gas, tert-butyl carbonate groups are isobutene gas and carbon dioxide, keto acid sites are carbon dioxide, keto acid esters such as tert-keto acid tert acid The butyloxy group generates carbon dioxide and isobutene gas.
Examples of those that react with the base include urethane groups and carbonate groups. By reacting with the base, the urethane group and the carbonate group generate carbon dioxide gas.

The form of the decomposable compound may be any of a monomer, an oligomer, and a polymer compound (polymer). Degradable compounds can be classified into the following compound groups.
(1) Non-curable low molecular weight degradable compound group (2) Curable low molecular weight degradable compound group (3) High molecular weight degradable compound group

The non-curable low molecular weight decomposable compound group (1) is a low molecular weight degradable compound group that does not cause a polymerization reaction even when radiation energy is applied. The curable low molecular weight decomposable compound group (2) is a compound group that cures by causing a polymerization reaction by application of radiation energy, and includes a polymerizable group such as a vinyl group. The polymer-based decomposable compound group (3) is a polymer compound (polymer) that is already a polymer.
The decomposable compound group may be used alone or in combination of two or more different types. When the curable low molecular weight decomposable compound group (2) or the high molecular weight degradable compound group (3) is used, it is easy to form uniform microbubbles and has a superior strength. It is possible and preferable.
Specific examples of the decomposable compound are listed below, but are not limited to those exemplified.

(1) -a, non-curable low molecular weight decomposable compound group (acid decomposable)
1-tert-butoxy-2-ethoxyethane,
2- (tert-butoxycarbonyloxy) naphthalene,
N- (tert-butoxycarbonyloxy) phthalimide,
2,1-bis [p- (tert-butoxycarbonyloxy) phenyl] propane and the like (1) -b, non-curing low molecular weight degradable compounds (base degradability)
N- (9-fluorenylmethoxycarbonyl) piperidine, etc.

(2) -a, curable low molecular weight degradable compound group (acid decomposable)
tert-butyl acrylate,
tert-butyl methacrylate,
tert-butoxycarbonylmethyl acrylate,
2- (tert-butoxycarbonyl) ethyl acrylate,
p- (tert-butoxycarbonyl) phenyl acrylate,
p- (tert-butoxycarbonylethyl) phenyl acrylate,
1- (tert-butoxycarbonylmethyl) cyclohexyl acrylate,
4-tert-butoxycarbonyl-8-vinylcarbonyloxy-tricyclo [5.2.1.02,6] decane,
2- (tert-butoxycarbonyloxy) ethyl acrylate,
p- (tert-butoxycarbonyloxy) phenyl acrylate,
p- (tert-butoxycarbonyloxy) benzyl acrylate,
2- (tert-butoxycarbonylamino) ethyl acrylate,
6- (tert-butoxycarbonylamino) hexyl acrylate,
p- (tert-butoxycarbonylamino) phenyl acrylate,
p- (tert-butoxycarbonylamino) benzyl acrylate,
p- (tert-butoxycarbonylaminomethyl) benzyl acrylate,
(2-tert-butoxyethyl) acrylate,
(3-tert-butoxypropyl) acrylate,
(1-tert-butyldioxy-1-methyl) ethyl acrylate,
3,3-bis (tert-butyloxycarbonyl) propyl acrylate,
4,4-bis (tert-butyloxycarbonyl) butyl acrylate,
p- (tert-butoxy) styrene,
m- (tert-butoxy) styrene,
p- (tert-butoxycarbonyloxy) styrene,
m- (tert-butoxycarbonyloxy) styrene,
Acryloyl acetate, methacryloyl acetate tert-butyl acryloyl acetate,
N- (tert-butoxycarbonyloxy) maleimide such as tert-butylmethacloyl acetate

(2) -b, a curable low molecular weight degradable compound group (base degradability)
4-[(1,1-dimethyl-2-cyano) ethoxycarbonyloxy] styrene,
4-[(1,1-dimethyl-2-phenylsulfonyl) ethoxycarbonyloxy] styrene,
4-[(1,1-dimethyl-2-methoxycarbonyl) ethoxycarbonyloxy] styrene,
4- (2-cyanoethoxycarbonyloxy) styrene,
(1,1-dimethyl-2-phenylsulfonyl) ethyl methacrylate,
(1,1-dimethyl-2-cyano) ethyl methacrylate, etc.

(3) -a, polymer-based degradable compound group (acid-decomposable)
Poly (tert-butyl acrylate),
Poly (tert-butyl methacrylate),
Poly (tert-butoxycarbonylmethyl acrylate),
Poly [2- (tert-butoxycarbonyl) ethyl acrylate],
Poly [p- (tert-butoxycarbonyl) phenyl acrylate],
Poly [p- (tert-butoxycarbonylethyl) phenyl acrylate],
Poly [1- (tert-butoxycarbonylmethyl) cyclohexyl acrylate],
Poly {4-tert-butoxycarbonyl-8-vinylcarbonyloxy-tricyclo [5.2.1.02,6] decane},
Poly [2- (tert-butoxycarbonyloxy) ethyl acrylate],
Poly [p- (tert-butoxycarbonyloxy) phenyl acrylate],
Poly [p- (tert-butoxycarbonyloxy) benzyl acrylate],
Poly [2- (tert-butoxycarbonylamino) ethyl acrylate],
Poly [6- (tert-butoxycarbonylamino) hexyl acrylate],
Poly [p- (tert-butoxycarbonylamino) phenyl acrylate],
Poly [p- (tert-butoxycarbonylamino) benzyl acrylate],
Poly [p- (tert-butoxycarbonylaminomethyl) benzyl acrylate],
Poly (2-tert-butoxyethyl acrylate),
Poly (3-tert-butoxypropyl acrylate),
Poly [(1-tert-butyldioxy-1-methyl) ethyl acrylate],
Poly [3,3-bis (tert-butyloxycarbonyl) propyl acrylate],
Poly [4,4-bis (tert-butyloxycarbonyl) butyl acrylate],
Poly [p- (tert-butoxy) styrene],
Poly [m- (tert-butoxy) styrene],
Poly [p- (tert-butoxycarbonyloxy) styrene],
Poly [m- (tert-butoxycarbonyloxy) styrene],
Polyacryloyl acetic acid, polymethacryloyl acetic acid,
Poly [tert-butyl acroyl acetate],
Poly [tert-butyl methacryloyl acetate]
N- (tert-butoxycarbonyloxy) maleimide / styrene copolymer, etc.

(3) -b, polymeric degradable compound group (base degradability)
Poly {p-[(1,1-dimethyl-2-cyano) ethoxycarbonyloxy] styrene},
Poly {p-[(1,1-dimethyl-2-phenylsulfonyl) ethoxycarbonyloxy] styrene},
Poly {p-[(1,1-dimethyl-2-methoxycarbonyl) ethoxycarbonyloxy] styrene},
Poly [p- (2-cyanoethoxycarbonyloxy) styrene],
Poly [(1,1-dimethyl-2-phenylsulfonyl) ethyl methacrylate],
Poly [(1,1-dimethyl-2-cyano) ethyl methacrylate],

  Organic polymer compounds such as polyethers, polyamides, polyesters, polyimides, polyvinyl alcohols and dendrimers into which degradable functional groups have been introduced can also be used as acid-decomposable or base-decomposable polymer compounds. Furthermore, an acid-decomposable or base-decomposable polymer compound in which a degradable functional group is introduced into an inorganic compound such as silica can also be used. Especially, it is preferable that a decomposable functional group is introduce | transduced into the compound group which has a functional group chosen from the group which consists of a carboxylic acid group or a hydroxyl group, and an amine group.

In order to increase the water resistance of the foam, it is also possible to use a compound in which a decomposable foaming functional group is introduced into a compound containing at least one kind of hydrophobic functional group. The hydrophobic functional group is preferably selected from the group consisting mainly of an aliphatic group, an alicyclic group, an aromatic group, a halogen group, and a nitrile group.
However, the decomposable functional group is easily introduced into a hydrophilic functional group selected from the group consisting of a carboxylic acid group, a hydroxyl group, and an amine group. A composite compound composed of a degradable unit having a functional functional group introduced therein and a hydrophobic unit containing a hydrophobic functional group is preferred. In particular, a vinyl copolymer compound is preferable.
Hydrophobic units include aliphatic (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate, aromatic vinyl compounds such as styrene, methylstyrene and vinylnaphthalene, (meth) acrylonitrile compounds, acetic acid A vinyl compound group, a vinyl chloride compound group, etc. are mentioned.

Specific examples of the decomposable compound comprising a composite compound of a decomposable unit and a hydrophobic unit are shown below.
tert-butyl acrylate / methyl acrylate copolymer tert-butyl acrylate / methyl methacrylate copolymer tert-butyl methacrylate / methyl acrylate copolymer tert-butyl methacrylate / methyl methacrylate copolymer tert-butyl acrylate / ethyl acrylate copolymer Tert-butyl acrylate / ethyl methacrylate copolymer tert-butyl methacrylate / ethyl acrylate copolymer tert-butyl methacrylate / ethyl methacrylate copolymer tert-butyl acrylate / styrene copolymer tert-butyl acrylate / vinyl chloride copolymer tert-butyl acrylate / acrylonitrile copolymer p- (tert-butoxycarbonyloxy) styrene / Styrene copolymer

Moreover, the decomposable unit and the hydrophobic unit in the decomposable compound can be used singly or in combination of two or more. The form of copolymerization can take any form such as random copolymerization, block copolymerization, and graft copolymerization. The copolymerization ratio of the hydrophobic unit is preferably 5 to 95% by mass with respect to the total amount of the decomposable compound, and considering the decomposable foamability of the decomposable compound and the environmental preservation of the foamed structure, 20 to 80%. The mass% is more preferable.
The decomposable compounds may be used alone or in combination of two or more different types. The decomposable compound becomes a compound containing at least one kind of hydrophobic functional group after the decomposable and foamable functional group is decomposed and desorbed to generate a bubble forming gas.

  In order to increase the water resistance of the foam, the foamable composition is decomposed into a hygroscopic compound having an equilibrium water absorption of less than 10% measured by the JIS K7209D method in an environmental atmosphere at a temperature of 30 ° C. and a relative humidity of 60%. A compound into which a group is introduced can also be used. Examples of the low hygroscopic compound having a structure in which a decomposable and foamable functional group can be easily introduced include p-hydroxystyrene and m-hydroxystyrene. Accordingly, examples of the decomposable compound include p- (tert-butoxy) styrene, m- (tert-butoxy) styrene, p- (tert-butoxycarbonyloxy) styrene, and m- (tert-butoxycarbonyloxy) styrene. These may be a curable monomer or a polymer in which one or more kinds are mixed.

  Further, a decomposable and foamable functional group may be introduced into a composite compound composed of a combination of a highly hygroscopic compound having a water absorption rate of 10% or more and a low hygroscopic compound having a water absorption rate of less than 10%. However, the composite compound preferably has a water absorption of less than 10% by an appropriate combination. For example, a copolymer (composite compound) of acrylic acid, which is a highly hygroscopic compound, and p-hydroxystyrene, which is a low hygroscopic compound, has a copolymerization ratio of acrylic acid / p-hydroxystyrene = 90/10 to 0 / 100 is preferable.

Specific examples of the decomposable compound comprising a combination of a high hygroscopic compound and a low hygroscopic compound are shown below.
tert-butyl acrylate / p- (tert-butoxy) styrene copolymer tert-butyl acrylate / m- (tert-butoxy) styrene copolymer tert-butyl acrylate / p- (tert-butoxycarbonyloxy) styrene copolymer tert-butyl acrylate / m- (tert-butoxycarbonyloxy) styrene copolymer tert-butyl methacrylate / p- (tert-butoxycarbonyloxy) styrene copolymer

Furthermore, a decomposable and foamable functional group may be introduced into a low hygroscopic polymer material selected from the group consisting of polyester, polyimide, polyvinyl acetate, polyvinyl chloride, polyacrylonitrile, phenol resin, and dendrimer. .
The decomposable compounds may be used alone or in combination of two or more different types. The decomposable compound becomes a low hygroscopic compound after the decomposable and foaming functional group is decomposed and eliminated to generate a bubble forming gas.

(Other resins)
In the composition (C), in addition to the acid generator or base generator and the decomposable foamable compound, it may be necessary to mix a general resin serving as a skeleton of the molded article. That is, when a non-curable low molecular weight decomposable compound group is used, it cannot be molded alone, so it is necessary to use it by mixing with the following commonly used resins. A general resin may be either compatible or incompatible when mixed with a decomposable compound.
General resins include polyester resins such as polyethylene terephthalate and polybutylene terephthalate, unsaturated polyester resins, polycarbonate resins, polyolefin resins such as polyethylene and polypropylene, polyolefin composite resins, polystyrene resins, polybutadiene resins, (meth) acrylic resins, Acryloyl resin, ABS resin, fluororesin, polyimide resin, polyacetal resin, polysulfone resin, vinyl chloride resin, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, starch, polyvinyl alcohol, polyamide resin, phenol resin, melamine resin, urea resin, urethane resin, It can be appropriately selected from commonly used resins such as epoxy resins and silicone resins. Moreover, a gas barrier resin can also be used for the purpose of allowing a low-boiling volatile substance that decomposes and gasifies from a decomposable compound to be contained in the molded body. The gas barrier resin may be mixed, coated or laminated, and in order to allow the low boiling point volatile substance to be contained in the molded body, it is preferable to coat or laminate the molded body surface.
Among the decomposable foaming compounds, the curable low molecular weight decomposable compound group and the high molecular degradable compound group may be used alone or in combination with the generally used resins.

Whether or not the above general resin is used, other unsaturated organic compounds that are cured by radiation energy can be used in combination. Examples of combination compounds include
(1) Aliphatic, alicyclic, aromatic 1-6 valent alcohols and polyalkylene glycol (meth) acrylates (2) Aliphatic, alicyclic, aromatic 1-6 valent alcohols with alkylene (Meth) acrylates of compounds obtained by adding oxides (3) poly (meth) acryloylalkylphosphate esters (4) reaction products of polybasic acids, polyols and (meth) acrylic acid (5) Reaction product of isocyanate, polyol, (meth) acrylic acid (6) Reaction product of epoxy compound and (meth) acrylic acid (7) Reaction product of epoxy compound, polyol, (meth) acrylic acid (8) Melamine and A reaction product of (meth) acrylic acid can be mentioned.

Among the compounds that can be used in combination, curable monomers and resins can be expected to improve physical properties such as foam strength and heat resistance, and control foamability. Moreover, if a curable monomer is used for the decomposable compound and the combination compound, solvent-free molding can be performed, and a production method with less environmental load can be provided. For example, such materials are used in JP-A-8-17257 and JP-A-9-102230.
Specific examples of the combination compound include methyl acrylate, ethyl acrylate, lauryl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, caprolactone-modified tetrahydrofurfuryl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, dicyclohexyl acrylate, isobornyl acrylate, isobornyl methacrylate, benzyl acrylate Benzylmeta Acrylate, ethoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, methoxypropylene glycol acrylate, phenoxy polyethylene glycol acrylate, phenoxy polypropylene glycol acrylate, ethylene oxide modified phenoxy acrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, 2-ethylhexyl carbitol acrylate, ω-carboxypolycaprolactone monoacrylate, phthalic acid monohydroxyethyl acrylate, acrylic acid dimer, 2-hydroxy-3-phenoxypropyl acrylate, acrylic acid-9,10-epoxidized oleyl, ethylene maleate Glycol monoacrylate, disic Pentenyloxyethylene acrylate, acrylate of caprolactone adduct of 4,4-dimethyl-1,3-dioxolane, acrylate of caprolactone adduct of 3-methyl-5,5-dimethyl-1,3-dioxolane, polybutadiene acrylate, ethylene oxide modified Phenoxylated phosphate acrylate, ethanediol diacrylate, ethanediol dimethacrylate, 1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol di Methacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol diacrylate, 1,9-nonanediol dimethacrylate, di Ethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, neopentyl glycol diacrylate, 2-butyl-2-ethylpropanediol diacrylate, ethylene oxide modified bisphenol A diacrylate, Polyethylene oxide modified bisphenol A diacrylate, polyethylene oxide modified hydrogenated bisphenol A diacrylate, propylene oxide modified bisphenol A diacrylate, polypropylene oxide modified bisphenol A diacrylate, ethylene oxide modified isocyanuric acid diacrylate, pentaerythritol diacrylate monostearate 1,6-hexanediol diglycidyl ether acrylic acid adduct, polyoxyethylene epichlorohydrin modified bisphenol A diacrylate, trimethylolpropane triacrylate, ethylene oxide modified trimethylolpropane triacrylate, polyethylene oxide modified trimethylolpropane triacrylate, Propylene oxide modified trimethylolpropane triacrylate, polypropylene oxide modified trimethylolpropane triacrylate, pentaerythritol triacrylate, ethylene oxide modified isocyanuric acid triacrylate, ethylene oxide modified glycerol triacrylate, polyethylene oxide modified glycerol triacrylate, propylene oxide modified glycerol triacrylate Polypropylene oxide modified glycerol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, caprolactone modified dipentaerythritol hexaacrylate, polycaprolactone modified Although dipentaerythritol hexaacrylate etc. can be mentioned, it is not restricted to these.

  Furthermore, as part or all of the combined active energy ray-curable unsaturated organic compound, an active energy ray-curable resin having a molecular weight of about 400 to 5000 having a (meth) acryloyl group at the molecular chain end can be combined. . As such a curable resin, for example, polyurethane poly (meth) acrylate polymers such as polyurethane-modified polyether poly (meth) acrylate and polyurethane-modified polyester poly (meth) acrylate are preferably used.

(Additive)
The foamable composition used in the present invention can contain additives other than the acid generator or the base generator and the decomposable compound, if necessary. Additives include inorganic or organic compound fillers, dispersants such as various surfactants, reactive compounds and antioxidants such as polyvalent isocyanate compounds, epoxy compounds and organometallic compounds, silicone oils and processing aids. Contains one or more agents, UV absorbers, optical brighteners, anti-slip agents, antistatic agents, anti-blocking agents, anti-fogging agents, light stabilizers, lubricants, softeners, colored dyes, other stabilizers, etc. May be.
By using additives, improvements in moldability, foamability, optical properties (particularly in the case of white pigments), electrical and magnetic properties (particularly in the case of conductive particles such as carbon) and the like can be expected.

Specific examples of inorganic compound fillers include titanium oxide, magnesium oxide, aluminum oxide, silicon oxide, calcium carbonate, barium sulfate, magnesium carbonate, calcium silicate, aluminum hydroxide, clay, talc, silica and other pigments, stearic acid Metal soap such as zinc, as well as dispersants such as various surfactants, calcium sulfate, magnesium sulfate, kaolin, silicate clay, diatomaceous earth, zinc oxide, silicon oxide, magnesium hydroxide, calcium oxide, magnesium oxide, alumina, mica, Asbestos powder, glass powder, shirasu balloon, zeolite, etc. are achieved. Examples of the organic compound filler include cellulose powders such as wood powder and pulp powder.
Examples of the organic compound filler include cellulose powder such as wood powder and pulp powder, and polymer beads. As the polymer beads, for example, those produced from acrylic resin, styrene resin or cellulose derivative, polyvinyl resin, polyvinyl chloride, polyester, polyurethane and polycarbonate, monomers for crosslinking, and the like can be used.
These fillers may be a mixture of two or more.

  Specific examples of the ultraviolet absorber are selected from salicylic acid-based, benzophenone-based, or benzotriazole-based ultraviolet absorbers. Examples of salicylic acid-based ultraviolet absorbers include phenyl salicylate, pt-butylphenyl salicylate, p-octylphenyl salicylate, and the like. Examples of the benzophenone ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone. Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-5′-t-butylphenyl) benzotriazole and the like.

Specific examples of the antioxidant include monophenol-based, bisphenol-based, polymer-type phenol-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.
A typical example of the light stabilizer is a hindered amine compound.

The softening agent can be used for the purpose of improving moldability or processability of the molded body. Specifically, ester compounds, amide compounds, hydrocarbon polymers having side chains, mineral oils, liquid paraffins, Examples thereof include waxes.
The ester compound used as the softening agent is not particularly limited as long as it is a mono- or polyester having a structure composed of an alcohol and a carboxylic acid, and even a compound having a hydroxyl group and a carbonyl group terminal in the molecule is blocked in the form of an ester group. It may be a compound. Specifically, stearyl stearate, sorbitan tristearate, epoxy soybean oil, refined castor oil, hydrogenated castor oil, dehydrated castor oil, epoxy soybean oil, extremely hardened oil, trioctyl trimellitic acid, ethylene glycol dioctanoate, pentaerythritol tetra Examples include octanoate.
The amide compound is not particularly limited as long as it is a mono- or polyamide compound having a structure composed of an amine and a carboxylic acid, and may be a compound in which the amino group and carbonyl group ends are left in the molecule, or a compound blocked in the form of an amide group. Good. Specifically, stearic acid amide, behenic acid amide, hexamethylene bis stearic acid amide, trimethylene bisoctylic acid amide, hexamethylene bishydroxy stearic acid amide, triocta trimellitic acid amide, distearyl urea, butylene bis stearic acid Amides, xylylene bis stearic acid amides, distearyl adipic acid amides, distearyl phthalic acid amides, distearyl octadecadioic acid amides, epsilon caprolactam, and derivatives thereof.

  The hydrocarbon polymer having a side chain is preferably a poly α-olefin and classified into a normal oligomer having a side chain having 4 or more carbon atoms. Specifically, ethylene-propylene copolymer and its maleic acid derivative, isobutylene polymer, butadiene, isoprene oligomer and hydrogenated product thereof, 1-hexene polymer, polystyrene polymer and the like are derived from these. Derivatives thereof, hydroxypolybutadiene and hydrogenated products thereof, and terminal hydroxypolybutadiene hydrogenated products.

(Light scattering fine particles)
Light-scattering fine particles may be supplementarily added to the foamable composition such as the composition (C) in order to improve luminance and suppress luminance unevenness. Examples of the light scattering fine particles include acrylic, styrene-acrylic, and polyethylene organic crosslinked polymer beads, silicon beads, and hollow particles. Further, the light scattering fine particles may be phase-separated on a nanoscale, and in that case, the effect of miniaturizing the bubbles formed from the foamable composition and increasing the number density can be obtained.

  The foamable composition such as the composition (C) can be prepared using a general kneader. For example, two rolls, three rolls, cowless resolver, homomixer, sand grinder, planetary mixer, ball mill, kneader, high speed mixer, homogenizer, and the like. An ultrasonic disperser or the like can also be used.

<Method for producing foam>
The foam constituting the light guide of the present invention is a foam obtained by applying radiation energy and thermal energy to the foamable composition. The manufacturing method which manufactures a foam from a foamable composition is equipped with the shaping | molding process which uses a foamable composition as a molded object, and the foaming process which provides a radiation energy and thermal energy to the said molded object, and makes it foam.

(Molding process)
The molding step of the foamable composition is a step of molding the foamable composition into a molded body having a desired shape. As a shape of a molded object, a sheet-like thing (a film form is included) is preferable. The sheet-like material may be an independent sheet that does not use a support or a sheet layer that is in close contact with the support.
The molding step in the present invention is a step for determining the shape. The molded body at the stage of the molding process may be a fluid instead of a solid. For example, a liquid material poured into a specific mold is also included in the molded body in the present invention.

As a method for forming the sheet-like material, a method described in Japanese Patent Application Laid-Open No. 2004-2812 or Japanese Patent Application No. 2003-199521 can be used. In general, melt extrusion molding, injection molding, coating molding, and press molding are preferable. In particular, coating molding is preferable because the light guide itself can be thinned and can be easily laminated on a translucent resin support.
Moreover, a batch type or a continuous type may be used. When the foamable composition is a solution, a solvent drying treatment may be added. It is also possible to laminate a plurality of molded bodies.

  In the case of coating molding, after applying the foamable composition to the support using a coating head, if the foamable composition is a solution diluted with a solvent or the like, the solvent content is removed with a dryer, A sheet layer made of a foamable composition is obtained on the support. At this time, the sheet | seat layer which consists of a foamable composition can also be obtained by peeling a sheet | seat layer from a support body. Coating methods include bar coating, air doctor coating, blade coating, squeeze coating, air knife coating, roll coating, gravure coating, transfer coating, comma coating, smoothing coating, and micro gravure. Examples include coating method, reverse roll coating method, multi-roll coating method, dip coating method, rod coating method, kiss coating method, gate roll coating method, falling curtain coating method, slide coating method, fountain coating method, and slit die coating method. .

Specific examples of the support include paper, synthetic paper, plastic resin sheet, metal sheet, metal vapor deposition sheet, and the like, and these may be used alone or may be laminated with each other. The plastic resin sheet is, for example, a general-purpose plastic sheet such as a polystyrene resin sheet, a polyolefin resin sheet such as polyethylene or polypropylene, and a polyester resin sheet such as polyethylene terephthalate, an engineering resin such as a polyimide resin sheet, an ABS resin sheet, or a polycarbonate resin sheet. A plastic sheet etc. are mentioned, Moreover, aluminum, copper, etc. are mentioned as a metal which comprises a metal sheet. Examples of the metal deposition sheet include an aluminum deposition sheet, a gold deposition sheet, and a silver deposition sheet.
Further, if a functional sheet such as a light reflecting sheet, a light diffusing sheet, or a prism sheet is used as a support, it is possible to easily integrate the light guide unit made of a foam and these functional sheets. .

  In the case of extrusion molding, a general extrusion molding method using a screw-like extrusion shaft, a ram extrusion molding method using a piston-like extrusion shaft, and the like can be mentioned. For example, a foamable composition extruded from an extruder can be extruded from a die to obtain a sheet-like material via a roll or the like.

Depending on the composition, the foamable composition may be decomposed by heating at, for example, 150 ° C. or higher. Therefore, care must be taken not to lose the net foaming performance prior to the foaming step.
For example, in extrusion molding, when foaming performance is impaired when heated to the melt viscosity of the resin, a solution casting method in which a foamable composition solution is prepared using a solvent in the same manner as in coating molding, and molding is performed at room temperature. You can also take the following method.

(Foaming process)
The foaming step is a step of imparting radiation energy and thermal energy to the molded body to cause foaming. The foaming process includes a radiation irradiation process for irradiating the molded body with radiation and a heating process for heating the molded body. When only fine bubbles are formed, the heating process is preferably performed after the radiation irradiation process. A stable foam can be formed by sequentially performing the radiation irradiation step and the heating step. This is because the foaming mechanism of the composition (c) is a mechanism in which an acid or base is generated by radiation, and the decomposable and foamable compound is decomposed and foamed by the acid or base and heating. The composition (c) generates a large number of bubble nuclei at a relatively low temperature, and when the temperature is further increased to grow the bubbles, fine bubbles can be made uniform. However, if the temperature is raised from the beginning and radiation is applied to it, large bubbles will be formed.
Each step may be performed continuously or discontinuously.

(Radiation irradiation process)
The radiation used in the radiation irradiation step is preferably ionizing radiation such as electron beam, ultraviolet ray, visible light, and γ-ray. In these, it is especially preferable to use an electron beam or an ultraviolet-ray.

  When irradiating with an electron beam, in order to obtain a sufficient transmission power, an electron beam accelerator having an acceleration voltage of 30 to 1000 kV, more preferably 30 to 300 kV is used, and the absorbed dose of one pass is controlled to 0.5 to 20 Mrad. It is preferable (1 rad = 0.01 Gy). When the acceleration voltage or the electron beam irradiation amount is lower than the above range, the transmission power of the electron beam becomes insufficient, and the inside of the molded body cannot be sufficiently transmitted. On the other hand, if it is larger than this range, not only the energy efficiency is deteriorated, but also the strength of the obtained molded article becomes insufficient, the resin and additives contained therein are decomposed, and the quality of the obtained foam is low. It can be unsatisfactory.

  As the electron beam accelerator, for example, an electro curtain system, a scanning type, a double scanning type, or the like can be used. When the electron beam is irradiated, if the oxygen concentration in the irradiation atmosphere is high, generation of acid or base and / or curing of the curable decomposable compound may be hindered. For this reason, it is preferable to replace the air in the irradiation atmosphere with an inert gas such as nitrogen, helium or carbon dioxide. The oxygen concentration in the irradiation atmosphere is preferably 1000 ppm or less, and more preferably 500 ppm or less in order to obtain more stable electron beam energy.

  When irradiating with ultraviolet rays, an ultraviolet lamp generally used in the semiconductor / photoresist field, the ultraviolet curing field, or the like can be used. Typical UV lamps include, for example, halogen lamps, halogen heater lamps, xenon short arc lamps, xenon flash lamps, ultra high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, medium pressure mercury lamps, deep UV lamps, metal halide lamps. There are noble gas fluorescent lamps, krypton arc lamps, excimer lamps, etc., and in recent years, there are also Y-ray lamps that emit an extremely short wavelength (peak at 214 nm). Some of these lamps are ozone-less types that generate less ozone. These ultraviolet rays may be scattered light or parallel light with high straightness.

In order to accurately control the position of the bubble distribution, it is preferable to use parallel light as the radiation. For the ultraviolet irradiation, various lasers such as ArF excimer laser, KrF excimer laser, YAG laser via a harmonic unit including a nonlinear optical crystal, and ultraviolet light emitting diodes can be used.
The emission wavelength of the ultraviolet lamp, laser, or ultraviolet light emitting diode is not limited as long as it does not interfere with the foamability of the foamable composition. Preferably, the photoacid generator or the photobase generator is more efficient in acid or base efficiency. The emission wavelength that is often generated is good. That is, an emission wavelength that overlaps with the photosensitive wavelength region of the photoacid generator or photobase generator to be used is preferable. Furthermore, a light emission wavelength that overlaps the maximum absorption wavelength or the maximum absorption wavelength in the photosensitive wavelength region of these generators is more preferable because the generation efficiency increases. The energy irradiation intensity of ultraviolet rays is appropriately determined depending on the foamable composition.

When an ultraviolet lamp having a high irradiation intensity typified by various mercury lamps and metal halide lamps is used, productivity can be improved, and the irradiation intensity (lamp output) is preferably 30 W / cm or more. The cumulative irradiation light quantity (J / cm ² ) of ultraviolet rays is obtained by adding the irradiation time to the energy irradiation intensity, and is appropriately determined depending on the foamable composition and the desired bubble distribution. It may be set according to the extinction coefficient of the acid generator or base generator. For stable and continuous production, a range of 1.0 mJ / cm ^{2 to 20} J / cm ² is preferable.
When using an ultraviolet lamp, the irradiation time can be shortened because the irradiation intensity is high. When using an excimer lamp or excimer laser, the irradiation intensity is weak, but it is close to a single light, so if the emission wavelength is optimized for the photosensitive wavelength of the generator, higher generation efficiency and foamability Is possible. When the amount of irradiation light is increased, heat generation may interfere with foaming properties depending on the ultraviolet lamp. At that time, a cooling treatment such as a cold mirror can be performed.

(Heating process)
Although there is no restriction | limiting in particular in the heater which can be used at a heating process, What can be heated by contact heating, induction heating, resistance heating, dielectric heating (and microwave heating), infrared heating, etc. can be illustrated.
Specific examples include an electric or gas infrared dryer using radiant heat, a roll heater using electromagnetic induction, an oil heater using an oil medium, an electric heater, and a hot air dryer using these hot airs. It is done.
In contact heating in which a heating body is brought into contact with the molded body and heated, a heating body such as a metal block, a metal plate, or a metal roll can be used.
In contact heating, heating may be performed while applying pressure. In this case, a hot press machine used for press molding can be used.

In the case of dielectric heating and infrared heating, since the internal heating method directly heats the inside of the material, it is preferable to perform uniform heating instantaneously compared to an external heating method such as a hot air dryer. In the case of dielectric heating, high-frequency energy having a frequency of 1 MHz to 300 MHz (wavelength 30 m to 1 m) is used. A frequency of 6 MHz to 40 MHz is often used. Among dielectric heating, especially microwave heating uses microwaves with a frequency of 300 MHz to 300 GHz (wavelength 1 m to 1 mm), but 2450 MHz and 915 MHz (same as a microwave oven) are often used.
In the case of infrared heating, an electromagnetic wave having a wavelength of 0.76 to 1000 μm in the infrared region is used. Although the optimum band of the wavelength selected varies depending on the situation from the heater surface temperature and the infrared absorption spectrum of the material to be heated, it is preferable to use a wavelength band of 1.5 to 25 μm, more preferably 2 to 15 μm. it can.

  Furthermore, a heating method used in a general thermal recording printer can also be used. For example, a thermal head that generates heat when an electric current is passed and laser thermal transfer can be used, and a foam having the same pattern can be obtained by writing heat. When obtaining high definition or high resolution, laser thermal transfer is preferable to thermal heads.

<Non-uniform foaming>
The foam used in the present invention is a non-uniform foam whose bubble occupation area ratio varies depending on the position in order to provide a function as a light guide. Bubble occupying area ratio in the present invention and (%) is an index for evaluating the cell density, the foam from the cross section of the observation image by the image analysis, when the maximum bubble diameter of less than 1μm in the cross-section of 100 [mu] m ² When the maximum bubble diameter is 1 μm or more and 5 μm, it is the ratio of the area occupied by the bubble cross section in the 2500 μm ² cross section, and when the maximum bubble diameter is 5 μm or more, the cross section of 10000 μm ² .
The distribution of the desired bubble occupation area ratio (hereinafter sometimes referred to as “bubble distribution”) is (a) radiation energy applied to the molded body, (b) thermal energy applied to the molded body, and (c) the above. Any one or more of the concentration of the decomposable and foaming functional group in the molded body and (d) the concentration of the acid generator or base generator in the molded body is obtained by a predetermined non-uniform distribution.

(Non-uniform radiation energy)
A method of setting the radiation energy applied to the molded body to a predetermined nonuniform distribution will be described.
The distribution of radiation energy can be controlled by adjusting the irradiation energy intensity by using a photomask for electron beam or ultraviolet irradiation.
There are various types of photomask patterns, such as a gradient pattern in which the transmission of radiation energy changes continuously, a gradation pattern that changes stepwise at a certain interval, and a division pattern that is divided according to the presence or absence of transparency. These are designed and used suitable for the desired bubble distribution pattern.
As the material of the photomask, a chrome mask, a metal mask, a silver salt glass mask, a silver salt film, a screen mask, or the like can be used. A mask in which glass is ion-etched, a mask in which interference fringes of a planar lens having a condensing function are drawn with an electron beam, and the like can be used. When irradiating ultraviolet rays with a wavelength of 300 nm or less, it is preferable to use quartz glass as the base material of the photomask.

When irradiation is performed using a photomask, methods such as contact irradiation and projection irradiation can be employed. In order to transfer the pattern of the photomask with high accuracy, it is preferable that the irradiated light is uniform parallel light.
Examples of the exposure system for irradiating parallel light include an optical system using an integrator and a parabolic mirror, an optical system using a Fresnel lens, and an optical system using a honeycomb board and a diffusion plate (http: / /www.kuranami.co.jp/toku_guide01.htm).
In order to obtain high uniformity, an optical system using an integrator and a parabolic mirror is generally preferable, and a short arc lamp is preferable as a light source used in this optical system. Examples of the short arc lamp include a metal halide lamp, an ultra-high pressure mercury lamp, a mercury xenon lamp, a sodium lamp, and a Y-ray lamp. After a photomask is brought into close contact with a molded body made of a foamable composition, partial foaming having a line and space pattern with a width of several μm is obtained by irradiating parallel ultraviolet light and foaming by heating. The edge at that time can also be clearly transferred.
Further, a method of irradiating radiation that generates interference fringes is also possible.

(Non-uniform thermal energy)
In order to obtain a predetermined non-uniform distribution of heat energy applied to the molded body, heat treatment is performed in the heating process so as to generate a heat energy intensity distribution. Specifically, it is preferable to control by heating temperature. For example, there is a method of heating using a thermal recording printer so that the applied thermal energy has a continuous gradient.

(Non-uniform foaming composition)
The concentration of the decomposable foamable functional group in the molded body and / or the concentration distribution of the acid generator (or base generator) in the molded body is preferably adjusted by using a plurality of foamable compositions having different compositions. .
For example, the foaming composition from which the mixing ratio of a decomposable compound and a photo-acid generator differs can be mentioned by apply | coating and shape | molding on a support body in parallel.

(3D bubble distribution)
The methods of non-uniformity of radiation energy, non-uniformity of thermal energy, and non-uniformity of the foamable composition described above as methods for non-uniform bubble distribution are independent from each other. The bubble distribution can be affected. Therefore, by combining two or more of these methods, it is possible to control the direction of the bubble distribution in the same foam in three dimensions.

(Bubble diameter)
The bubble distribution can be controlled by the above method. In this case, the bubble diameter may be changed along with the bubble density evaluated by the bubble occupation area ratio. When the bubble density increases, the bubble diameter also increases, and when the bubble density decreases, the bubble diameter also tends to decrease.
However, it is also possible to change the cell density intensively by adjusting the composition of the foamable composition. For example, by increasing the glass transition point of the foamable composition, it is possible to mainly change the bubble density while keeping the bubble diameter relatively small. Further, by using a three-dimensional crosslinkable foamable composition, it is possible to mainly change the bubble density while keeping the bubble diameter relatively small.
The bubbles in the foam of the present invention are preferably constituted with a bubble diameter of 20 μm or less, more preferably constituted with a bubble diameter of 10 μm or less. By setting the thickness to 20 μm or less, not only the optical function can be sufficiently exhibited, but also the light guide itself can be thinned.

<Light guide>
The light guide of the present invention includes at least a light guide part, and is appropriately combined with a light reflection part, a prism part, and a light diffusion part as necessary.
In the light guide unit of the present invention, the bubble occupation area ratio has a predetermined distribution pattern. Preferably, it has a low foaming area of 0.5% or less and a high foaming area of 1% or more.
The bubble occupation area ratio in the low foaming region may be 0%. If the area occupied by bubbles in the low foam area is lowered, the amount of change in the area occupied by bubbles in the entire light guide section can be increased, so the distribution of light emitted from the light guide section can be fully controlled and uniformized. Easy to do. As a result, a light diffusion effect can be obtained, and it is not necessary to separately provide a light diffusion portion.
The area occupied by bubbles in the highly foamed region is more preferably 15% (equivalent to an expansion ratio of about 1.1 times) or more, and more preferably 30% (equivalent to an expansion ratio of about 1.2 times) or more. preferable. Increasing the area occupied by bubbles in the high-foaming region can increase the amount of change in the area occupied by bubbles in the entire light guide, so that the distribution of light emitted from the light guide is sufficiently controlled and uniform. Easy to do. However, even in the highly foamed region, it is preferable to have a bubble occupation area ratio of 65% or less (corresponding to a foaming ratio of about 2 times) or less. Thereby, it becomes easy to maintain the intensity | strength of a light guide part.

Between the low foaming area and the high foaming area, the middle foaming area where the bubble occupation area ratio gradually increases from the side adjacent to the low foaming area toward the side adjacent to the high foaming area so as to connect between the two areas. It is preferable to provide. That is, it is preferable that the light guide of the present invention is configured such that the bubble occupation area ratio gradually increases from the low foaming region toward the high foaming region.
There may be a plurality of low foaming regions and high foaming regions. For example, low foaming regions may be arranged on both sides of the high foaming region so that the bubble occupation area ratio gradually increases and then gradually decreases.
It is preferable that the bubble distribution in each region is uniform, but a configuration in which dot-like portions composed of a group of fine bubbles are scattered may be used. When dot-like portions are scattered, a low-foaming region is obtained by reducing the dot density, and a high-foaming region is obtained by increasing the dot density. In addition, it is preferable that the inside of each dot-shaped part is a high bubble occupation area rate to the same extent as a light reflecting part to be described later.

When the light guide of the present invention is used, the low foam area of the light guide is located near the light source, and the high foam area is located away from the light source. In other words, the area closest to the light source has the smallest occupied area ratio and is used in such an arrangement that the bubble occupied area ratio is maximized at the farthest place.
The bubbles in the light guide are preferably configured with a bubble diameter in the range of 0.1 to 20 μm, and more preferably configured with a bubble diameter in the range of 0.1 to 10 μm. By setting the bubble diameter to be equal to or less than the wavelength of visible light, bubbles and dot-like portions are hardly visible. Therefore, the light diffusion sheet can be omitted .
For specific bubble distribution in the light guide, set parameters related to the shape and position of the light source, the area of the light guide, etc., and make full use of optical simulation software and ray tracing methods that take into account Mie scattering and multiple scattering. Can be optimized.

The light reflection part of the present invention has a bubble occupation area ratio of 15% or more, preferably 30% or more. If the bubble occupation area ratio of the light reflecting portion is increased, the reflectance can be increased. However, even the light reflecting portion preferably has a bubble occupation area ratio of 65% or less. Thereby, it becomes easy to maintain the intensity | strength of a light reflection part.
The bubble distribution in the light reflecting portion is preferably uniform in order to prevent uneven light reflection. Moreover, it is preferable that the bubble in a light reflection part is comprised with the bubble diameter of the range of 0.1-10 micrometers, and it is more preferable that it is comprised with the bubble diameter of the range of 0.2-1 micrometer.
When the bubble occupation area ratio is in the range of 30 to 65% and the bubble diameter is in the range of 0.2 to 1 μm, the total light reflectance can be 80% or more with a thickness of 50 μm or less.

The light diffusion part of the present invention has a bubble occupation area ratio of 30% or less, preferably 15% or less. If the bubble occupying area ratio of the light diffusion portion is lowered, the total light transmittance can be increased and the light utilization efficiency can be increased. However, even if it is a light-diffusion part, it is preferable to have a bubble occupation area ratio of 0.5% or more. Thereby, sufficient light-diffusion effect can be exhibited.
The bubble distribution in the light diffusion portion is preferably uniform in order to prevent uneven light reflection. Moreover, it is preferable that the bubble in a light reflection part is comprised with the bubble diameter of the range of 0.1-20 micrometers, and it is more preferable that it is comprised with the bubble diameter of the range of 0.1-10 micrometers.
Specific bubble occupying area ratio, bubble diameter, and thickness of the light diffusing portion are set so that the total light reflectance is 60% or more, preferably 80% or more.
The prism portion of the present invention is configured as a layer in which a V-groove is engraved on one surface so as to exhibit a prism function. The prism portion does not require air bubbles and is formed of a general resin. However, it is also possible to use the foamable composition without foaming.

Hereinafter, embodiments of the light guide according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments.
FIG. 1 is a perspective view showing a first embodiment (light guide) of the present invention. The light guide of this embodiment is composed of only the light guide unit 10. The light guide unit 10 is made of a foam in which a large number of bubbles B are formed in the matrix M, and a bubble distribution pattern in which the bubble occupation area ratio gradually increases from the end surface 11 on the side where incident light enters to the end surface 12 on the opposite side. It has become. That is, the vicinity of the end surface 11 is a low foaming region 13, the vicinity of the end surface 12 is a high foaming region 14, and the space between the low foaming region 13 and the high foaming region 14 is a medium foaming region 15. The bubble diameter may gradually increase from the end surface 11 to the end surface 12 together with the bubble occupation area ratio.
The light guide according to the present embodiment is provided with such a bubble distribution pattern so that substantially uniform light is emitted from the entire emission surface 16.

FIG. 2 is an example of a method for manufacturing the light guide of FIG. As shown in FIG. 2, a matrix 1 is formed by irradiating a molded body 1 in which a foamable composition is preliminarily formed using a photomask 2 whose energy permeability is a gradation pattern, with radiation having a gradation pattern. The light guide unit 10 having the bubbles B with a gradient distribution in M can be obtained.
FIG. 3 is another example of a method for manufacturing the light guide in FIG. As shown in FIG. 3, when the photomask 2 provided with the triangular opening 3 is slid on the molded body 1 during the radiation irradiation, the irradiation time is shorter when the triangular apex side 3a slides, The bottom side 3b has a long irradiation time. It is obvious that the same effect can be obtained by sliding the molded body 1. By generating the distribution in the irradiation time in this way, the distribution of the radiation energy is created as in the case of using the gradation pattern photomask, and the light guide unit 10 having the bubbles B in an inclined distribution is obtained. Can do.

FIG. 4 is a perspective view showing a second embodiment (light guide) of the present invention. The light guide of this embodiment is also composed of only the light guide unit 10. The light guide unit 10 is made of a foam in which a large number of dot-shaped portions D are formed in the matrix M, and the distribution of the dot-shaped portions D gradually increases from the end surface 11 on the side where incident light enters to the end surface 12 on the opposite side. It has become. Since each dot-shaped portion D is an aggregate of a large number of bubbles B, when the entire light guide 10 is viewed from the viewpoint of bubble distribution, the occupied area ratio of bubbles from the end surface 11 on the side where incident light enters to the end surface 12 on the opposite side. The bubble distribution pattern is such that gradually increases. That is, the vicinity of the end surface 11 is a low foaming region 13, the vicinity of the end surface 12 is a high foaming region 14, and the space between the low foaming region 13 and the high foaming region 14 is a medium foaming region 15.
The light guide according to the present embodiment is provided with such a bubble distribution pattern so that substantially uniform light is emitted from the entire emission surface 16. In addition, in order to suppress the visibility of each dot-shaped part D more, you may laminate | stack a light-diffusion part as needed.

FIG. 5 is a perspective view showing a third embodiment (light guide) of the present invention. Although the light guide of this embodiment is also comprised only by the light guide part 10, the light guide 10 is made into the laminated body of the foam 10a and the transparent resin 10b.
The foam 10a is substantially the same as the light guide unit 10 of the first embodiment. That is, it is made of a foam in which a large number of bubbles B are formed in the matrix M, and has a bubble distribution pattern in which the bubble occupation area ratio gradually increases from the end surface 11a on the side where incident light is incident to the end surface 12a on the opposite side. .
One transparent resin 10b does not have bubbles. Examples of the material of the transparent resin 10b include acrylic resins such as polymethyl methacrylate, methacrylic resins, cyclic olefin resins such as norbornene, polycarbonate resins, celluloses such as cellulose triacetate, styrene resins, and blends of two or more of these materials. The mixed resin is preferable.
In this embodiment, the vicinity of the end surfaces 11a and 11b is the low foaming region 13, the vicinity of the end surfaces 12a and 12b is the high foaming region 14, and the space between the low foaming region 13 and the high foaming region 14 is the medium foaming region 15. . As with the light guide unit 10 of the first embodiment, the bubble diameter may gradually increase from the end surface 11a to the end surface 12a together with the bubble occupation area ratio.
The light guide of the present embodiment is provided with such a bubble distribution pattern, so that substantially uniform light is emitted from the entire emission surface 16 (the upper surface of the transparent resin 10b).

The light guide of FIG. 5 can be manufactured by bonding the foam 10a obtained in the same manner as the light guide of the first embodiment and the transparent resin 10b. Moreover, as shown in FIG. 6, it can manufacture using an in-mold injection molding method.
As shown in FIG. 6, in the in-mold injection molding method, first, a roll-wrapped transparent resin sheet 4 is passed between molds 5a and 5b for injection molding (step (1)). Next, the transparent resin sheet 4 is sandwiched between the molds 5a and 5b, the foamable composition 6 is injected and filled into the molds 5a and 5b, and the transparent resin sheet 4 and the foamable resin composition are integrated. (Step (2)). Then, after the filled foamable composition 6 is solidified, the molds 5a and 5b are removed (step (3)). Then, the transparent resin sheet 4 is sent (step (4)). Hereinafter, by repeating steps (1) to (4), a large number of laminates in which the transparent resin sheet 4 and the foamable resin composition are integrated can be obtained. The light guide shown in FIG. 5 can be obtained by applying radiation energy and thermal energy to the laminate to cause foaming in a predetermined pattern. In addition, before or after a foaming process, it is necessary to cut the laminated body connected in roll shape separately.

FIG. 7 is a perspective view showing a fourth embodiment (light guide) of the present invention. Although the light guide of this embodiment is also comprised only by the light guide part 10, the light guide 10 is made into the laminated body of the foam 10a and the transparent resin 10b.
The foam 10a is substantially the same as the light guide unit 10 of the second embodiment. That is, the foam 10a is made of a foam in which a large number of dot-shaped portions D are formed in the matrix M, and the distribution of the dot-shaped portions D gradually increases from the end surface 11a on the incident light side to the end surface 12a on the opposite side. It is like that. Each dot-like portion D is an aggregate of many bubbles B.
One transparent resin 10b does not have bubbles. As the material of the transparent resin 10b, the same material as the transparent resin 10b of the third embodiment can be used.
When the entire light guide unit 10 is viewed from the viewpoint of bubble distribution, the bubble distribution pattern is such that the bubble occupation area ratio gradually increases from the end surfaces 11a and 11b on the side where incident light is incident to the end surfaces 12a and 12b on the opposite side. .
Also in this embodiment, the vicinity of the end surfaces 11a and 11b is the low foaming region 13, the vicinity of the end surfaces 12a and 12b is the high foaming region 14, and the space between the low foaming region 13 and the high foaming region 14 is the medium foaming region 15. . As with the light guide unit 10 of the first embodiment, the bubble diameter may gradually increase from the end surface 11a to the end surface 12a together with the bubble occupation area ratio.
The light guide of the present embodiment is provided with such a bubble distribution pattern, so that substantially uniform light is emitted from the entire emission surface 16 (the upper surface of the transparent resin 10b).

  The light guide body of FIG. 7 can be manufactured by bonding the foam 10a obtained in the same manner as the light guide body of the second embodiment and the transparent resin 10b. Moreover, it can manufacture using the in-mold injection molding method similarly to 3rd Embodiment.

FIG. 8 is a perspective view showing a fifth embodiment (light guide) of the present invention. The light guide body of this embodiment includes a light guide portion 10 and a light reflection portion 20 provided in contact with the three end faces thereof. As the light guide unit 10, the light guide unit 10 in the first to fourth embodiments can be appropriately employed. By providing the light reflecting section 20 around the end face of the light guide section 10, the light utilization efficiency can be increased.
As a manufacturing method of the light guide of the present embodiment, the plate-shaped molded product of the foamable composition is irradiated with radiation by covering only a region where the light guide unit 10 is to be formed with a photomask (inclined pattern or the like), The method of heating and foaming after that is mentioned. That is, the portion through the photomask becomes the light guide unit 10 having a bubble distribution pattern with the radiation dose controlled, and the surrounding area protruding from the photomask is irradiated with a uniform and sufficient radiation dose to produce a large number of microbubble groups. Is a light reflecting portion 20 that is uniformly embedded at high density.

FIG. 9 is a perspective view showing a sixth embodiment (light guide) of the present invention. The light guide body of the present embodiment includes a light guide unit 10 and a light reflection unit 20 provided in contact with the opposing surface of the emission surface 16. As the light guide unit 10, the light guide unit 10 in the first to fourth embodiments can be appropriately employed. By providing the light reflecting portion 20, the light utilization efficiency can be increased.
As a method of manufacturing the light guide according to this embodiment, two plate-shaped molded products of a foamable composition are prepared, one side is irradiated with radiation through a photomask (an inclined pattern or the like), and the other side is entirely exposed. A method of uniformly irradiating with radiation, then laminating both, and heating and foaming while integrating them may be mentioned. That is, the part through the photomask becomes the light guide unit 10 having the bubble distribution pattern with the radiation dose controlled, and the part irradiated uniformly without using the photomask is irradiated with the radiation dose uniformly and sufficiently. Thus, the light reflecting portion 20 in which the microbubbles are uniformly contained at a high density is obtained.
Alternatively, as another method, the foamed composition plate-shaped product is irradiated with radiation through a photomask (inclined pattern), and further, the back surface layer is irradiated with radiation at a shallow irradiation depth to be heated and foamed. Can be manufactured. That is, the portion through the photomask becomes the light guide portion 10 having a bubble distribution pattern, and the back side thereof is irradiated with irradiation energy locally, so that the light reflection in which fine bubbles are uniformly included in the surface layer at high density. Part 20.

FIG. 10 is a perspective view showing a seventh embodiment (light guide) of the present invention. The light guide according to the present embodiment includes a light guide 10 and a prism part 30 provided in contact with the emission surface 16. As the light guide unit 10, the light guide unit 10 in the first to fourth embodiments can be appropriately employed.
As a method of manufacturing the light guide according to the present embodiment, a translucent resin is formed on a mold in which V-grooves to be prisms are engraved in advance, and then a photomask (inclined pattern) is taken out without removing it from the mold. ), A plate-like molded product of the foamable composition irradiated with light is added, heated and pressurized, and foamed simultaneously with the lamination to produce. When taken out from the mold after foaming, a light guide body in which a light guide portion having a bubble distribution pattern and a prism layer of a V groove are integrated on the surface thereof is obtained.
Further, the in-mold injection molding method described in the third embodiment can be used. In this case, a prism sheet may be used instead of the transparent resin sheet 4 in FIG.

  The light guide of the present invention may be a combination of the fifth to seventh embodiments as appropriate. For example, it is good also as a structure which has the light reflection part 20 in contact with the opposing surface of the three directions end surface of the light guide part 10, and its output surface 16. FIG. Moreover, it is good also as a structure which added the prism part 30 to this.

<Surface emitting device>
The surface light-emitting device of the present invention includes the light guide of the present invention and a light source disposed in proximity to or in contact with the incident surface side of the light guide. As the light source, a linear light source such as a cold cathode tube or a point light source such as a light emitting diode (LED) can be appropriately employed.
The surface light-emitting device of the present invention can be used for various display devices in the same manner as conventional surface light-emitting devices. For example, it can be used as a backlight or a front light of a liquid crystal display device used for a display of a television, a mobile phone, a personal computer, an automobile or the like. Moreover, it can also be used as internal illumination of a display device used for a guide sign board, a signboard, a traffic sign or the like in a station or public facility. It can also be used for general lighting used in offices and homes.

Hereinafter, embodiments of a surface light-emitting device of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments.
FIG. 11 is a perspective view showing an eighth embodiment (surface emitting device) of the present invention. The surface light-emitting device of this embodiment includes a light guide 100 and light sources 200 and 200 provided in proximity to or in contact with the incident surface 11 of the light guide 100. In the present embodiment, a plurality of (preferably 3 to 4) white chip LEDs are used as the light source 200.
The light guide 100 includes a light guide unit 10 and a reflection unit 20. Since the light guide unit 10 is equivalent to the light guide unit 10 of the first embodiment, the same components are denoted by the same reference numerals and detailed description thereof is omitted. The reflection unit 20 includes an end surface light reflection unit 20 a that contacts the three end surfaces of the light guide unit 10, and a back surface light reflection unit 20 b that contacts the opposite surface of the emission surface 16.

The surface light-emitting device in this embodiment can be manufactured, for example, according to the following procedure. First, as shown in FIG. 12, the foamable composition is molded into a plate shape, and further irradiated with radiation so that the inside 51 becomes the light guide portion 10 and the three side faces 52 become the end face light reflection portions 20a. Prepare 50. On the other hand, as shown in FIG. 13, a plate 53 irradiated with radiation is prepared so as to be the back light reflecting portion 20b.
Next, the light guide 100 is produced by superposing and pressing the plate 50 of FIG. 12 and the plate 53 of FIG. 13 while heating them, and foaming them while integrating the two plates.
Then, the surface light-emitting device of this embodiment is obtained by fixing the light sources 200 and 200 at regular intervals so as to face the incident surface 11 of the light guide unit 10.
Note that when the light sources 200 and 200 are fixed, a gap through which light leaks may be covered with a white seal or the like. In addition, instead of the white chip LED, the light source 200, 200 may be a cold cathode tube arranged in parallel, but the white chip LED is easier to downsize.

FIG. 14 is a perspective view showing a ninth embodiment (surface emitting device) of the present invention. The surface light-emitting device of this embodiment includes a light guide 100 and a light source 200 provided in proximity to or in contact with the incident surface 11 of the light guide 100. In the present embodiment, a cold cathode tube is used as the light source 200.
The light guide 100 includes a light guide unit 10 and a reflection unit 20. Since the light guide unit 10 is equivalent to the light guide unit 10 of the first embodiment, the same components are denoted by the same reference numerals and detailed description thereof is omitted. The reflection unit 20 includes an end surface light reflection unit 20 a that contacts the three end surfaces of the light guide unit 10, a back surface light reflection unit 20 b that contacts the opposite surface of the emission surface 16, and the light source 200 on the incident surface 11 side of the light guide unit 10. It is comprised from the light source reflection part 20c provided so that it might cover. This light source reflecting portion 20c is provided with a U-shaped groove-like through groove 20d opened on the incident surface 11 side, and the light source 200 is inserted therein.

The surface light-emitting device in this embodiment can be manufactured, for example, according to the following procedure. First, as shown in FIG. 15, the foamable composition is molded into a plate shape, and the inner 51 is the light guide unit 10, and the four side surfaces 52 are the end surface light reflection unit 20 a and the light source reflection unit 20 c as appropriate. A plate 50 irradiated with radiation is prepared. On the other hand, as shown in FIG. 16, a plate 53 irradiated with radiation is prepared so as to be the back light reflecting portion 20b.
Next, the plate 50 shown in FIG. 15 and the plate 53 shown in FIG. 16 are overlapped and heated and pressed, the two plates are integrated and foamed, and then the through-groove 20d is drilled to thereby guide the light guide 100. Create
Thereafter, the surface light emitting device of the present embodiment is obtained by inserting the light source 200 into the through groove 20d.
In the present embodiment, since the light source 200 is built in the through groove 20d in the light source reflector 20c, light leakage from the cold cathode tube can be prevented almost completely. As the light source 200, a white chip LED may be used instead of the cold cathode tube.

FIG. 17 is a perspective view showing a tenth embodiment (surface emitting device) of the present invention. The surface light-emitting device of this embodiment includes a light guide 100 and light sources 200 and 200 provided in proximity to or in contact with the incident surface 11a of the light guide 100. In the present embodiment, a pair of white chip LEDs are used as the light source 200. The light guide 100 includes a light guide unit 10 and a reflection unit 20.
The light guide unit 10 includes an output unit 10c and an introduction unit 10d provided in contact with the incident surface 11b of the output unit 10c. Since the structure of the light emission part 10c is equivalent to the light guide part 10 of 1st Embodiment, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted.
The introduction portion 10d has a bubble distribution pattern that gradually decreases after the bubble occupation area ratio gradually increases from the incident surface 11a to the opposite incident surface 11a (not shown) along the incident surface 11b. That is, the vicinity of both incident surfaces 11a is the low foaming region 13, the central part is the high foaming region 14, and the space between the low foaming region 13 and the high foaming region 14 (both sides of the high foaming region 14) is the medium foaming region 15. ing. In addition, the bubble diameter may be increased or decreased with the increase or decrease of the bubble occupation area ratio. The introduction part 10d can emit substantially uniform light toward the incident surface 11b by providing the bubble distribution pattern. As a result, substantially uniform light is emitted from the entire emission surface 16 of the emission part 10c.
The reflecting portion 20 includes an end surface light reflecting portion 20a that contacts the three end surfaces of the emitting portion 10c, an introducing reflecting portion 20d that contacts the end surface opposite to the incident surface 11b of the introducing portion 10d, and a back surface that contacts the opposing surface of the emitting surface 16. The light reflection part 20b is comprised.

The surface light-emitting device in this embodiment can be manufactured, for example, according to the following procedure. First, as shown in FIG. 18, the foamable composition is molded into a plate shape, and the interior 51 is formed as the light guide unit 10, and the four side surfaces 52 are formed as the end surface light reflection unit 20 a and the introduction reflection unit 20 d as appropriate. A plate 50 irradiated with radiation is prepared. On the other hand, as shown in FIG. 19, a plate 53 irradiated with radiation is prepared so as to become the back light reflecting portion 20b.
Next, the plate 50 shown in FIG. 18 and the plate 53 shown in FIG. 19 are overlapped and heated while being pressed, the two plates are integrated and foamed, and then a portion 52a of the side surface 52 in contact with the pair of incident surfaces 11a is formed. By removing the light guide 100, the light guide 100 is created.
Then, the surface light-emitting device of this embodiment is obtained by fixing the light sources 200 and 200 so as to face each incident surface 11a.
Note that when the light sources 200 and 200 are fixed, a gap through which light leaks may be covered with a white seal or the like. Further, a light reflecting portion (either a light reflecting portion made of a foam or a conventionally known reflecting sheet) may be provided on the introduction portion 10d.

The present invention will be described in detail by the following examples, but the present invention is not limited to these examples. Unless otherwise specified, “parts” and “%” in the examples represent “parts by mass” and “mass%”, respectively.

<Example 1>
Preparation of thin light guide plate (1) Sheet formation of foamable composition Copolymer of tert-butyl acrylate (60 wt%), methyl methacrylate (40 wt%) and methyl methacrylic acid (10 wt%) as decomposable compounds Acetic acid in which 3 parts of bis (4-tert-butylphenyl) iodonium perfluorobutanesulfonate (trademark: BBI-109, manufactured by Midori Chemical Co., Ltd.) was mixed as an iodonium salt-based acid generator with 100 parts. An ethyl solution was prepared (solid content: 25%). This solution was coated on a silicon-treated surface of a silicon PET sheet (trademark: Lumirror SP-PET-01-75BU, manufactured by Panac) using an applicator bar (trademark: Doctor blade TD type, manufactured by YOSHIMITSU SEIKI) having a coating thickness of 300 μm. Then, the solvent was removed by evaporation in a constant temperature dryer at a temperature of 110 ° C. to obtain a colorless and transparent coating layer. This coating layer was peeled from the silicon PET sheet to obtain a foamable film having a thickness of 50 μm.

(2) Flat plate forming The foamable film created in the step (1) is cut into dimensions of 50 mm in length and 35 mm in width, and 12 sheets thereof are stacked, as shown in FIGS. 20 (a) and 20 (b), It was sandwiched between flat-pressing dies having smooth surfaces (dimensions: 50 mm long and 35 mm wide) and heated and pressed using a hand press machine (trade name: Mini TEST PRESS-10 manufactured by TOYOSEIKI) (pressing pressure; 6 MPa, pressing temperature; 150 ° C. 3 minutes). Thereafter, as shown in FIG. 20 (c), when the pressure was returned to normal pressure and air-cooled to 40 ° C., the mold was removed to obtain a colorless and transparent foamable flat plate.

(3) UV irradiation As shown in FIG. 20D, the entire surface of the foamable flat plate obtained in the step (2) is covered with a quartz glass photomask (size: 50 mm length, 35 mm width). Then, it was irradiated with ultraviolet rays from above. As the photomask, an inclined pattern whose transmittance continuously changes in the longitudinal direction from 0 to 40% (measurement wavelength: 254 nm) was used. Ultraviolet rays were irradiated using a metal halide lamp (trademark; multi-metal lamp M03-L31 for ultraviolet curing, manufactured by Eyegraphic Co., Ltd.) as a light source so that the irradiation dose was 2200 mJ / cm ² . After the irradiation, the photomask was removed to obtain a colorless and transparent foamable flat plate similar to the step (1).

(4) Heating foaming As shown in FIG. 20 (e), the foamable flat plate irradiated with ultraviolet rays in the step (3) is sandwiched between flat pressing dies as in the step (2), and heated by a hand press. Foaming was performed (press pressure: 4 MPa, press temperature: 130 ° C. for 2 minutes). Thereafter, as shown in FIG. 20 (f), while being pressurized, cooling water was immediately circulated inside the mold and rapidly cooled to 50 ° C. Subsequently, as shown in FIG. 20 (g), when the pressure is returned to normal pressure and air-cooled to 40 ° C., the mold is removed, and as shown in FIG. 20 (h), a light guide part made of foam is obtained. It was.
The obtained light guide part is a flat plate having a uniform thickness from the incident surface side (light source side when used as a surface light emitting device) to the opposite surface side (opposite side of the incident surface). It was 600 μm. The micrometer (trademark: MCD-25M manufactured by Mitutoyo) was used for the thickness measurement. In addition, the light guide portion has a continuously changing transparency (the translucency is increased as the transmittance of the photomask is higher).

(5) Evaluation of foam structure In the cross section of 100 μm ² when the bubble diameter (average value of the bubble diameter) and the bubble occupation area ratio (when the maximum bubble diameter is less than 1 μm) of the light guide unit obtained in the step (4), When the maximum bubble diameter is 1 μm or more and 5 μm, the ratio of the area occupied by the bubble cross section in the cross section of 2500 μm ² and when the maximum bubble diameter is 5 μm or more in the cross section of 10000 μm ² ) Calculated from
The observation image of the cross section is obtained by freezing and cleaving the light guide unit immersed in liquid nitrogen in parallel from the incident surface toward the opposing surface, and subjecting the fractured surface to metal vapor deposition, and then scanning electron microscope (trademark: S-510). , Manufactured by Hitachi, Ltd., magnification 5000 times).
Then, after binarizing the bubbles and the matrix in the observation image, the bubble diameter and the bubble occupation area ratio were calculated using an image analyzer (trademark: Image Analyzer V10, manufactured by TOYOBO).
The obtained light guide portion had an inclined distribution in which the bubble diameter and the bubble occupation area ratio gradually increased from the incident surface toward the opposing surface. The maximum bubble diameter was 0.3 μm. Moreover, the bubble occupation area ratio changed from 0% to 16%.

(6) Surface light-emitting device and light emission evaluation Four white chip LEDs (manufactured by Nichia Chemical Co., Ltd., external dimensions; vertical length: 1.2 mm, horizontal) (1.8 mm, height 0.6 mm) were uniformly arranged. The incident direction at this time was adjusted so as to be along the direction in which the light guide part is translucent. In addition, a prism sheet having triangular prism-shaped irregularities formed on one side (outgoing surface) of the light guide portion and a light reflecting sheet (reflectance of 90% or more) on the opposite surface are arranged. A surface light-emitting device was obtained by incorporating the member into a white housing.
When the uniform light emitting property of the obtained surface light emitting device was visually evaluated, uniform light emission was exhibited without overlapping the light diffusion sheet, and the bubble distribution pattern was not visually recognized. That is, it was easy to obtain a light guide that was thin with a thickness of 0.6 mm, which was difficult with the prior art, and that uniformly emitted light without uneven brightness even without a light diffusion sheet.

<Example 2>
A foamable flat plate (A) was obtained in substantially the same manner as in steps (1) to (3) of Example 1. However, a photomask (dimensions: 48 mm long and 31 mm wide) smaller than the photomask used in step (3) of Example 1 was used. Then, align one side in the longitudinal direction of this photomask with the center of one side in the longitudinal direction of the foamable flat plate, and cover the foamable flat plate so that a gap (2 mm per circumference) is formed on the other three sides. I did it.
This foamable flat plate (A) and three foamable films (B) obtained by irradiating the foamable film obtained in the step (1) of Example 1 with ultraviolet rays (irradiation dose: 2200 mJ / cm ² ) were overlapped. The hot pressing was performed in the same manner as in step (4) of Example 1. As a result, it was possible to obtain an integrated light guide including light reflecting portions foamed at high density on the end surface and the lower surface of the light guide. The thickness of the light guide part of the obtained light guide was the same as that of the light guide part of Example 1.
When the bubble diameter and bubble occupation area ratio of the obtained light guide were obtained in the same manner as in Example 1, the light guide part was the same as in Example 1. On the other hand, the bubble diameter of the light reflecting portion was 0.4 μm and was uniform as a whole. Further, the area occupied by bubbles in the light reflecting portion was 52%, which was uniform as a whole. This light reflecting portion, unlike the translucent light guide portion, had a high light reflectance of 90% or more.
The uniform light emitting property was evaluated in substantially the same manner as in step (6) of Example 1, but the light reflecting sheet disposed on the light emitting facing surface was not used. This integrated light guide not only emits light uniformly as in Example 1, but also does not leak light from the gap with the white casing due to the light reflecting portion on the end face.

<Example 3>
After filling a mold (dimensions: length 50 mm × width 35 mm, depth 0.1 mm) in which triangular prism-shaped irregularities are regularly arranged with epoxy acrylic ultraviolet curable resin (made by Japan Synthetic Rubber), It was cured by irradiation with ultraviolet rays. The foamable flat plate obtained in the step (3) of Example 1 was placed on the cured surface, and foamed by hot pressing. As a result, an integrated light guide having a prism portion on the upper surface of the light guide was obtained. The thickness of the light guide part of the obtained light guide was the same as that of the light guide part of Example 1.
When the bubble diameter and bubble occupation area ratio of the obtained light guide were obtained in the same manner as in Example 1, the light guide part was the same as in Example 1. On the other hand, no foam structure was seen in the prism portion.
The uniform light emitting property was evaluated in substantially the same manner as in step (6) of Example 1, but no prism sheet disposed on the light output facing surface was used. This integrated light guide not only emits light uniformly as in the case of Example 1, but can also be a good surface light emitting device without using a separate prism sheet.

<Example 4>
After filling a mold (dimensions: length 50 mm × width 35 mm, depth 0.1 mm) in which triangular prism-shaped irregularities are regularly arranged with epoxy acrylic ultraviolet curable resin (made by Japan Synthetic Rubber), It was cured by irradiation with ultraviolet rays. On the cured surface, the foamable flat plate (A) and the foamable film (B) of Example 2 were overlapped in this order and simultaneously heated and pressed. As a result, an integrated light guide including a light guide part, a light reflection part, and a prism part was obtained. The thickness of the light guide part of the obtained light guide was the same as that of the light guide part of Example 1.
When the bubble diameter and bubble occupation area ratio of the obtained light guide were determined in the same manner as in Example 1, the light guide part and the light reflection part were the same as in Example 2. On the other hand, no foam structure was seen in the prism portion.
The uniform light emission was evaluated in substantially the same manner as in step (6) of Example 1, but the prism sheet and the light reflecting sheet were not used. Moreover, since there is no independent member, the white housing | casing for accommodating can also be omitted.
This integrated light guide not only emits light uniformly in the same manner as in Example 1, but also provides a good surface light emitting device without using a separate prism sheet, light reflecting sheet, and white housing.

<Example 5>
One foamable film obtained in the step (1) of Example 1 was irradiated with ultraviolet rays through an inclined pattern mask in the same manner as in the step (3) of Example 1. Then, it heat-pressed similarly to the process (4) of Example 1 with the polycarbonate resin plate (PC board; thickness 550 micrometers) which is transparent resin. The thickness of the whole light guide part of the obtained light guide was 600 μm, which is the same as that of the light guide part of Example 1. However, the thickness of the part which consists of a foam among them was 50 micrometers.
The bubble diameter and bubble occupying area ratio of the obtained light guide were determined in the same manner as in Example 1. As a result, the portion made of the foam was the same as in Example 1. On the other hand, no foamed structure was found on the resin plate. The bubble occupation area ratio as a whole of the light guide portion varied from 0% to 1.3%.
Further, when the uniform light emission was evaluated in substantially the same manner as in step (6) of Example 1, the same uniform light emission as in Example 1 was obtained.

<Example 6>
One foamable film obtained in the step (1) of Example 1 was irradiated with ultraviolet rays through a dot pattern mask (irradiation dose 330 mJ / cm ² ). At this time, a pattern in which the dot diameter and density gradually increased was used. Then, it heat-pressed like the process (4) of Example 1 with the polycarbonate resin plate (thickness 550 micrometers) which is transparent resin. The thickness of the whole light guide part of the obtained light guide was 600 μm, which is the same as that of the light guide part of Example 1. However, the thickness of the part which consists of a foam among them was 50 micrometers.
When the bubble diameter and bubble occupying area ratio of the obtained light guide were obtained in the same manner as in Example 1, as for the portion made of the foam, the slope distribution in which the dot-like portions gradually increase from the incident surface toward the opposing surface. It was. The maximum bubble diameter in the dot-like portion was 0.1 μm, and the bubble occupation area ratio was 4.5%, which was almost uniform within the dot. On the other hand, no foamed structure was found on the resin plate. The bubble occupation area ratio as a whole of the light guide portion varied from 0% to 0.38%.
Further, the uniform light emission was evaluated in substantially the same manner as in step (6) of Example 1. As a result, uniform light emission was observed without overlapping the light diffusion sheet, and the pattern of the dot-like portion was not visually recognized. That is, it was easy to obtain a light guide that was thin with a thickness of 0.6 mm, which was difficult with the prior art, and that uniformly emitted light without uneven brightness even without a light diffusion sheet.
In the light guide of this embodiment, incident light is refracted by dot-like objects having different refractive indexes, and is emitted according to Snell's law.

<Comparative Example 1>
Light-guided by melting and dispersing hollow particles (diameter 5-30 μm) with acrylic highly cross-linked polymer in the outer shell and injection-molding them into a wedge shape under conditions of a cylinder temperature of 230 ° C. and a mold temperature of 80 ° C. Got the body.
When the uniform light emitting property was evaluated in substantially the same manner as in step (6) of Example 1, most of the hollow particles contained therein had a bubble diameter of 10 μm or more, and therefore, when light was emitted without using a light diffusion sheet. The dispersion pattern of the hollow particles was visually recognized, resulting in uneven light emission.

<Comparative Example 2>
Pellets in which 0.1% by mass of methacrylic resin (Mitsubishi Rayon Co., Ltd.) and silicone particles (Toshiba Silicone Co., average particle size 12 μm) are uniformly mixed are injected into a wedge shape under conditions of a cylinder temperature of 240 ° C. and a mold temperature of 80 ° C. A light guide was obtained by molding.
Uniform light emission was evaluated in substantially the same manner as in step (6) of Example 1. As a result, uniform light emission was obtained without using a light diffusion sheet, but only a light guide plate having a thickness of 1 mm was obtained even if it was thin. . That is, since it is necessary to use injection molding, molding with a wall thickness of 1 mm or less becomes difficult. Moreover, since the silicone particles are used, the specific gravity is larger than that of the light guide of the example. Therefore, it is difficult to reduce the weight.

<Comparative Example 3>
The mixed pellet used in Comparative Example 2 was press-molded at a heating temperature of 240 ° C. so as to have a thickness of 600 μm. The uniform light emission was evaluated in substantially the same manner as in step (6) of Example 1. As a result, non-uniform light emission was obtained unless a light diffusion sheet was used. That is, a phenomenon has occurred in which the vicinity of the light source is bright and the distance from the light source is dark.
Table 1 summarizes the properties of the light guides of the above examples and comparative examples.

In Example 1 and Example 5 having a microbubble group and having a bubble distribution, a thin light guide that can emit light even without a light diffusion sheet and is equivalent to the minimum diameter of the LED light source is produced. I was able to. Moreover, in Examples 2-4, the light reflection part and the prism part could be integrated easily. Further, in Example 6 in which the distribution of the dot-like objects in the microbubble group is changed, both the translucency and the light scattering property can be achieved, so that the pattern of the dot-like objects is not visually recognized even without the light diffusion sheet. A light guide that can emit light uniformly was obtained.
On the other hand, in Comparative Example 1 in which the hollow particles were dispersed, the bubble diameter was 10 μm or more, and the dispersion pattern was visually recognized, resulting in uneven light emission. Moreover, in Comparative Examples 2-3 in which fine particles are dispersed, uniform light emission and thinning cannot be achieved at the same time.

It is a perspective view which shows 1st Embodiment (light guide) of this invention. It is an example of the manufacturing method of 1st Embodiment (light guide) of this invention. It is another example of the manufacturing method of 1st Embodiment (light guide) of this invention. It is a perspective view which shows 2nd Embodiment (light guide) of this invention. It is a perspective view which shows 3rd Embodiment (light guide) of this invention. It is an example of the manufacturing method of 3rd Embodiment (light guide) of this invention. It is a perspective view which shows 4th Embodiment (light guide) of this invention. It is a perspective view which shows 5th Embodiment (light guide) of this invention. It is a perspective view which shows 6th Embodiment (light guide) of this invention. It is a perspective view which shows 7th Embodiment (light guide) of this invention. It is a perspective view which shows 8th Embodiment (surface light-emitting device) of this invention. It is explanatory drawing of the manufacturing method of 8th Embodiment (surface emitting device) of this invention. It is explanatory drawing of the manufacturing method of 8th Embodiment (surface emitting device) of this invention. It is a perspective view which shows 9th Embodiment (surface light-emitting device) of this invention. It is explanatory drawing of the manufacturing method of 9th Embodiment (surface emitting device) of this invention. It is explanatory drawing of the manufacturing method of 9th Embodiment (surface emitting device) of this invention. It is a perspective view which shows 10th Embodiment (surface light-emitting device) of this invention. It is explanatory drawing of the manufacturing method of 10th Embodiment (surface emitting device) of this invention. It is explanatory drawing of the manufacturing method of 10th Embodiment (surface emitting device) of this invention. It is explanatory drawing which shows the manufacture process of the light guide of the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Light guide part, 13 ... Low foam area, 14 ... High foam area, 15 ... Medium foam area,
M ... Matrix, B ... Bubble

Claims (10)

A step of applying radiation energy in a predetermined non-uniform distribution using a photomask to the foamable sheet (A) comprising a foamable composition that foams by application of radiation energy and thermal energy;
  A step of imparting radiation energy in a uniform distribution to the foamable sheet (B) comprising a foamable composition that foams upon application of radiation energy and thermal energy;
  Heating and pressing the foamable sheet (A) and foamable sheet (B) after application of radiation energy, and a process of foaming while integrating both,
The foamable sheet (A) is foamed so as to have a low foaming area with a bubble occupation area ratio of 0.5% or less, a high foaming area of 1% or more, and a high foaming area of 1% or more. The light guide is characterized in that a light guide part is formed in a part or all of the foamed sheet, and the foamable sheet (B) is foamed to have a bubble occupation area ratio of 15% or more to form a light reflecting part. Manufacturing method. A step of applying radiation energy in a predetermined non-uniform distribution using a photomask to the foamable sheet (A) comprising a foamable composition that foams by application of radiation energy and thermal energy;
  Heating and pressing the foamable sheet (A) and the prism sheet after the application of radiation energy, and the step of foaming the foamable sheet (A) while integrating both,
The foamable sheet (A) is foamed so as to have a low foaming area with a bubble occupation area ratio of 0.5% or less and a high foaming area with 1% or more, and a light guide part in a part or all of the foamed sheet (A). A method of manufacturing a light guide, characterized by comprising: A step of applying radiation energy in a predetermined non-uniform distribution using a photomask to the foamable sheet (A) comprising a foamable composition that foams by application of radiation energy and thermal energy;
  A step of imparting radiation energy in a uniform distribution to the foamable sheet (B) comprising a foamable composition that foams upon application of radiation energy and thermal energy;
  The prism sheet, the foamable sheet (A) after application of radiation energy, and the foamable sheet (B) after application of radiation energy are heated and pressed in this order, and the foamable sheet (A) and A step of foaming the foamable sheet (B),
The foamable sheet (A) is foamed so as to have a low foaming area with a bubble occupation area ratio of 0.5% or less and a high foaming area with 1% or more, and a light guide part in a part or all of the foamed sheet (A). And producing a light reflecting portion by foaming the foamable sheet (B) so that a bubble occupation area ratio is 15% or more. Application of radiation energy to the foamable sheet (A) is performed by covering a portion excluding at least part of the periphery of the foamable sheet (A) with a photomask,
The guide according to any one of claims 1 to 3, wherein a side surface on the peripheral side not covered with the photomask is foamed so that a bubble occupation area ratio is 15% or more to form a light reflecting portion on the side surface. Manufacturing method of light body. A step of applying radiation energy in a predetermined non-uniform distribution using a photomask to the foamable sheet (A) comprising a foamable composition that foams by application of radiation energy and thermal energy;
  Heating and pressing the foamable sheet (A) and the transparent sheet after the application of radiation energy, and the step of foaming the foamable sheet (A) while integrating both,
The foamable sheet (A) is foamed so as to have a low foaming area with a bubble occupation area ratio of 0.5% or less and a high foaming area with 1% or more. . The foamable composition that foams by the application of radiation energy and thermal energy is an acid generator that generates an acid by the action of ray energy or a base generator that generates a base, and one or more types reacting with the acid or base The method for producing a light guide according to any one of claims 1 to 5, comprising a decomposable and foamable compound having a decomposable and foamable functional group for decomposing and desorbing low-boiling volatile substances. A light guide manufactured by the method for manufacturing a light guide according to claim 1. Surface emitting device comprising a light guide according, and a light source in claim 7.   A display device comprising the surface light-emitting device according to claim 8.   An illumination device comprising the surface light-emitting device according to claim 8.

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