U.S. patent application number 10/152632 was filed with the patent office on 2003-02-27 for optical device and adhesive composition used therefor.
Invention is credited to Hori, Masahiro, Nakamura, Koichiro, Yamamoto, Hiroaki.
Application Number | 20030040596 10/152632 |
Document ID | / |
Family ID | 18737342 |
Filed Date | 2003-02-27 |
United States Patent
Application |
20030040596 |
Kind Code |
A1 |
Nakamura, Koichiro ; et
al. |
February 27, 2003 |
Optical device and adhesive composition used therefor
Abstract
An optical device having at least two optically transparent
optical parts which are bonded together with an optically
transparent adhesive layer. The adhesive layer is formed from a
matrix containing silicon, titanium, zirconium, aluminum or
germanium, and oxygen atoms. At least part of the atoms is bonded
to other atom(s) through a polyvalent hydrocarbon group and
directly bonded a monovalent hydrocarbon group. The refractive
index value of the adhesive layer approximates to the refractive
index values of the at least two optically transparent optical
parts. An adhesive composition for bonding optical parts and a
method of bonding optical parts are also proposed.
Inventors: |
Nakamura, Koichiro;
(Osaka-shi, JP) ; Hori, Masahiro; (Osaka-shi,
JP) ; Yamamoto, Hiroaki; (Osaka-shi, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
18737342 |
Appl. No.: |
10/152632 |
Filed: |
May 23, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10152632 |
May 23, 2002 |
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09670693 |
Sep 28, 2000 |
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6415093 |
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Current U.S.
Class: |
528/10 |
Current CPC
Class: |
G02B 6/4212 20130101;
C09J 183/04 20130101; C03C 27/10 20130101; G02B 6/3801 20130101;
C09J 185/00 20130101; G02B 6/32 20130101; C09J 183/14 20130101;
G02B 6/4239 20130101 |
Class at
Publication: |
528/10 |
International
Class: |
C08G 077/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 17, 2000 |
JP |
2000-247201 |
Claims
What is claimed is:
1. An optical device comprising at least two optically transparent
optical parts which are bonded together with an optically
transparent adhesive layer, wherein the adhesive layer is formed
from a matrix containing at least one type of specific atoms
selected from the group consisting of silicon, titanium, zirconium,
aluminum and germanium, and oxygen atoms, at least part of the
specific atoms is bonded to other specific atom(s) through a
polyvalent hydrocarbon group having 2 to 8 carbon atoms and
directly bonded to at least one monovalent hydrocarbon group
selected from the group consisting of an alkyl group, phenyl group,
monovalent fluorine-containing hydrocarbon group and monovalent
sulfur-containing hydrocarbon group, and the contents of the above
specific atom, the polyvalent hydrocarbon group and the monovalent
hydrocarbon group are adjusted such that the refractive index value
of the adhesive layer approximates to the refractive index values
of the at least two optically transparent optical parts.
2. The optical device of claim 1, wherein when the refractive index
values of the two adjacent optical parts are represented by n.sub.1
and n.sub.2 (n.sub.1.gtoreq.n.sub.2), the adhesive layer between
the adjacent optical parts has a refractive index n.sub.3
represented by the following expression (1): {square root}{square
root over ((n.sub.1.multidot.n.sub.2- ))}-(({square root}{square
root over ((n.sub.1.multidot.n.sub.2))}-n.sub.2-
)/3)-0.05.ltoreq.n.sub.3.ltoreq.{square root}{square root over
((n.sub.1.multidot.n.sub.2))}+((n.sub.1-{square root}{square root
over ((n.sub.1n.sub.2))})/3)+0.05 (1)
3. The optical device of claim 1, wherein when the refractive index
values of the two adjacent optical parts are represented by n.sub.1
and n.sub.2 (n.sub.1.gtoreq.n.sub.2), the adhesive layer between
the adjacent optical parts has a refractive index n.sub.3
represented by the following expression (2): {square root}{square
root over ((n.sub.1.multidot.n.sub.2- ))}-(({square root}{square
root over ((n.sub.1.multidot.n.sub.2))}-n.sub.2-
)/4)-0.03.ltoreq.n.sub.3.ltoreq.{square root}{square root over
((n.sub.1.multidot.n.sub.2))}+((n.sub.1-{square root}{square root
over ((n.sub.1n.sub.2))})/4)+0.03 (2)
4. The optical device of any one of claims 1 to 3, wherein the
adhesive layer contains the polyvalent hydrocarbon group and the
monovalent hydrocarbon group in amounts of 0.01 to 30 wt % and 30
to 80 wt %, respectively.
5. The optical device of any one of claims 1 to 4, wherein the
optical parts are optical fibers, lenses, filters, optical
waveguides, diffraction gratings or optical active elements.
6. The optical device of any one of claims 1 to 5, wherein one of
the at least two optical parts is an optical fiber and the other
optical part is a lens, filter or optical waveguide.
7. The optical device of any one of claims 1 to 5, wherein the at
least two optical parts are both optical fibers.
8. The optical device of any one of claims 1 to 7, wherein the at
least two optical parts are made from glass, plastic or
organic-inorganic composite material.
9. The optical device of any one of claims 1 to 7, wherein the at
least two optical parts are made from glass.
10. An adhesive composition for bonding optical parts comprising
the following components (A), (B) and (C): (A) organopolysiloxane
having at least two alkenyl groups having 4 or less carbon atoms
bonded to silicon atoms in the molecule; (B)
organohydrogenpolysiloxane having at least two hydrogen atoms
bonded to silicon atoms in the molecule; and (C) a platinum-based
catalyst.
11. The adhesive composition of claim 10, wherein the component (A)
has a viscosity of 100 to 250,000 cS at 25.degree. C.
12. The adhesive composition of claim 10 or 11, wherein the number
of hydrogen atoms contained in the component (B) is 0.4 to 6.0
times the total number of alkenyl groups contained in the component
(A), and the component (C) is contained in an amount of 10 to 1,000
ppm based on the total weight of the component (A) and the
component (B).
13. A method of bonding optical parts comprising the steps of
placing an adhesive composition comprising the following components
(A), (B) and (C) between at least two optical parts to be bonded
together and curing the adhesive composition: (A)
organopolysiloxane having at least two alkenyl groups having 4 or
less carbon atoms bonded to silicon atoms in the molecule; (B)
organohydrogenpolysiloxane having at least two hydrogen atoms
bonded to silicon atoms in the molecule; and (C) a platinum-based
catalyst.
14. The method of bonding optical parts of claim 13, wherein the
component (A) has a viscosity of 100 to 250,000 cS at 25.degree.
C.
15. The method of bonding optical parts of claim 13 or 14, wherein
the number of hydrogen atoms contained in the component (B) is 0.4
to 6.0 times the total number of alkenyl groups contained in the
component (A), and the component (C) is contained in an amount of
10 to 1,000 ppm based on the total weight of the component (A) and
the component (B).
Description
DETAILED DESCRIPTION OF THE INVENTION
[0001] The present invention relates to an optical device
comprising optical parts bonded together with an optically
transparent adhesive material, an adhesive composition for forming
the same and a bonding method.
[0002] Technologies for increasing communication capacity have been
acquiring greater importance due to the spread of the Internet.
Bonding technologies used for the assembly of optical parts and
optical elements used in optical fiber communication systems
require high reliability, accurate adjustment of refractive index
(for connecting optical paths), precise position accuracy (for
connecting lenses) and high heat resistance (solder heat
resistance). For the assembly of optical parts, soldering, laser
welding and an organic adhesive such as an acrylic resin or epoxy
resin have been used, or adhesives composed of organic-inorganic
composite materials prepared by a sol-gel method have been
proposed. (i) Proceedings of the 48th ECTC, pp. 1178-1185, 1998
proposes a fluorinated or sulfur-containing epoxy adhesive and
epoxy-acrylic adhesive and (ii) Journal of Non-crystalline Solids,
vol. 80, pp. 557-563, 1986 or (iii) Intl. Congr, On
Glass.multidot.S, pp. 29-436, 1986 discloses organic and inorganic
adhesives prepared by a sol-gel method. (iv) Japanese Patent No.
1829914 discloses an optical element which is produced using a
sol-gel adhesive composed of an alkoxide and a metal salt and (v)
Japanese Patent No. 2786996 discloses a prism which is constructed
using an adhesive composed of a silicate and alkoxide. Further,
(vi) U.S. Pat. No. 5,991,493 discloses an optical element which is
fabricated using an organic-inorganic composite adhesive, for
example, an adhesive obtained by hydrolyzing a sol consisting of
polydimethylsiloxane, methyltriethoxysilane and
phenyltrifluorosilane.
[0003] However, technologies and adhesives for bonding these
optical parts involve the following problems.
[0004] As for soldering and laser welding methods, fixed position
accuracy is unsatisfactory, or a laser light source or advanced
technology is required. Epoxy adhesives and acrylic adhesives (i)
are inferior in heat resistance of 250.degree. C. or more (solder
heat resistance). Adhesives comprising an alkoxide and a metal salt
(ii to vi) have such problems that the bonding strength of an
adhesive layer is insufficient because a cohesive failure readily
occurs in the adhesive layer and that bubbles remain by bonding
together optical parts such as lenses, the adhesive layer becomes
cloudy, or sufficient adhesion cannot be obtained because an
alcohol formed by a hydrolytic reaction or water formed by a
dehydration reaction is evaporated during thermal curing.
[0005] It is an object of the present invention to provide an
adhesive composition which improves the above problems, has high
adhesion strength and excellent heat resistance, and can be used to
bond optical parts together without producing such a defect as
cloudiness caused by bubbles by reducing the generation of bubbles
at the time of curing.
[0006] It is another object of the present invention to provide a
method of bonding optical parts using the adhesive composition of
the present invention.
[0007] It is still another object of the present invention to
provide an optical device comprising optical parts bonded together
with the adhesive composition of the present invention.
[0008] Other objects and advantages of the present invention will
become apparent from the following description.
[0009] According to the present invention, firstly, the above
objects and advantages of the present invention are attained by an
optical device comprising at least two optically transparent
optical parts which are bonded together with an optically
transparent adhesive layer, wherein the adhesive layer is formed
from a matrix containing at least one type of specific atoms
selected from the group consisting of silicon, titanium, zirconium,
aluminum and germanium, and oxygen atoms, at least part of the
specific atoms is bonded to other specific atom(s) through a
polyvalent hydrocarbon group having 2 to 8 carbon atoms and
directly bonded to at least one monovalent hydrocarbon group
selected from the group consisting of an alkyl group, phenyl group,
monovalent fluorine-containing hydrocarbon group and monovalent
sulfur-containing hydrocarbon group, and the contents of the above
specific atom, the polyvalent hydrocarbon group and the monovalent
hydrocarbon group are adjusted such that the refractive index value
of the adhesive layer approximates to the refractive index values
of the at least two optically transparent optical parts.
[0010] According to the present invention, secondly, the above
objects and advantages of the present invention are attained by an
adhesive composition for bonding optical parts together, which
comprises the following components (A), (B) and (C):
[0011] (A) organopolysiloxane having at least two alkenyl groups
having 4 or less carbon atoms bonded to silicon atoms in the
molecule;
[0012] (B) organohydrogenpolysiloxane having at least two hydrogen
atoms bonded to silicone atoms in the molecule; and
[0013] (C) a platinum-based catalyst.
[0014] According to the present invention, thirdly, the above
objects and advantages of the present invention are attained by a
method of bonding optical parts together, which comprises placing
an adhesive composition containing the above components (A), (B)
and (C) between at least two optical parts to be bonded together
and curing the adhesive composition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a sectional view of a first embodiment of the
present invention;
[0016] FIG. 2 is a sectional view of another embodiment of the
present invention;
[0017] FIG. 3 is a sectional view of still another embodiment of
the present invention;
[0018] FIG. 4 is a sectional view of a further embodiment of the
present invention;
[0019] FIG. 5 is a sectional view of a still further embodiment of
the present invention; and
[0020] FIG. 6 is a sectional view of a still further embodiment of
the present invention.
[0021] The present invention will be described in detail
hereinafter. A description is first given of the optical
device.
[0022] A polyvalent hydrocarbon group having 2 to 8 carbon atoms is
contained in the adhesive layer of the optical device of the
present invention. When the number of carbon atoms of the
polyvalent hydrocarbon group is too large, the heat resistance of
the adhesive layer lowers and the hydrophobic nature of the
adhesive layer increases, thereby deteriorating the adhesion of the
adhesive layer to the surface of glass or other optical part.
Therefore, the number of carbon atoms of the polyvalent hydrocarbon
group must be 8 or less, preferably 4 or less. The polyvalent
hydrocarbon group is selected from divalent to pentavalent
hydrocarbon groups. Examples of the divalent hydrocarbon group
having 4 or less carbon atoms include ethylene, trimethylene,
tetramethylene, methylethylene, ethylethylene, dimethylethylene,
vinylene, propenylene, butenylene, methylvinylene, ethylvinylene,
dimethylvinylene and methylpropenylene. Examples of the tervalent
hydrocarbon group having 4 or less carbon atoms include
1,2,3-propanetoluyl group and 1,2,4-butanetoluyl group. Examples of
the tetravalent hydrocarbon group having 4 or less carbon atoms
include 1,3-propanediyl-2-ylidene group, 1,3-butanediyl-2-ylidene
group and 1,4-butanediyl-2-ylidene group. Examples of the
pentavalent hydrocarbon group having 4 or less carbon atoms include
1,3-butanediyl-2,4-ylidene group and 1,4-butanediyl-2,3-ylidene
group. The hydrogen atoms of the polyvalent hydrocarbon group
having 4 or less carbon atoms may be substituted with heavy
hydrogen or elemental halogen such as fluorine, chlorine or
bromine. An adhesive layer having high transmission of light having
a communication wavelength of 1.55 .mu.m or 1.3 .mu.m can be
provided by substituting with heavy hydrogen or halogen. Out of
these, ethylene, trimethylene and tetramethylene are preferred and
ethylene is the most preferred from the viewpoints of synthesis
ease and heat resistance.
[0023] The monovalent hydrocarbon group contained in the adhesive
layer of the optical device of the present invention is selected
from an alkyl group, aryl group, monovalent fluorine-containing
hydrocarbon group and monovalent sulfur-containing hydrocarbon
group. Examples of the alkyl group include methyl, ethyl, propyl,
butyl, pentyl, hexyl, heptyl, octadecyl and the like. Examples of
the aryl group include phenyl, methylphenyl, ethylphenyl,
dimethylphenyl, trimethylphenyl, biphenyl, naphthyl and the like.
Examples of the monovalent fluorine-containing hydrocarbon group
include trifluoromethyl, pentafluoroethyl, heptafluoropropyl,
trifluoropropyl and the like. Examples of the monovalent
sulfur-containing hydrocarbon group include hydrocarbon groups
having a thiol group, sulfide group, disulfide group, polysulfide
group or sulfone group.
[0024] The hydrogen atom of these monovalent hydrocarbon groups may
be substituted with heavy hydrogen or elemental halogen such as
fluorine, chlorine or bromine. An adhesive layer having high
transmission of light having a communication wavelength of 1.55
.mu.m or 1.3 .mu.m can be provided by substituting with heavy
hydrogen or halogen. Out of these, methyl, phenyl and
trifluoromethyl are preferred from the viewpoints of synthesis
ease, heat resistance and the control of refractive index.
[0025] The adhesive layer of the optical device of the present
invention is formed from a matrix containing at least one type of
specific atoms selected form the group consisting of silicon,
titanium, zirconium, aluminum and germanium, and oxygen atoms. At
least one of the specific atoms is bonded to other specific atom(s)
through a polyvalent hydrocarbon group having at least 2 carbon
atoms. At least one of the specific atoms is directly bonded to at
least one monovalent hydrocarbon group selected from the group
consisting of an alkyl group, phenyl group, monovalent
fluorine-containing hydrocarbon group and monovalent
sulfur-containing hydrocarbon group. The each content of the
specific atoms, the polyvalent hydrocarbon group and the monovalent
hydrocarbon group are adjusted such that the refractive index value
of the adhesive layer should approximate to the refractive index
values of the at least two optically transparent optical parts.
[0026] The adhesion strength of the adhesive layer can be increased
and the refractive index thereof can be adjusted by using at least
one type of specific atoms (may be referred to as "network forming
atoms" hereinafter) selected from the group consisting of silicon,
titanium, zirconium, aluminum and germanium as the atoms forming
the basic skeleton of a compound forming the adhesive layer of the
optical device of the present invention. For example, silicon atoms
are used to provide an adhesive layer having excellent heat
resistance, weatherability, humidity resistance and chemical
resistance. A matrix is formed by using titanium, zirconium,
aluminum or germanium alone or mixing with other element such as
silicon to provide an adhesive layer having excellent heat
resistance, weatherability, humidity resistance and chemical
resistance and a large refractive index. At least one of the
network forming atoms of the present invention is bonded to other
network forming atom(s) through a polyvalent hydrocarbon group
having at least two carbon atoms.
[0027] When the above network forming atom is a silicon atom and
the polyvalent hydrocarbon group is a divalent hydrocarbon group
such as an ethylene group (--CH.sub.2CH.sub.2--), at least part of
silicon atoms is bonded to other silicon atom through the ethylene
group as shown in the following formula (3). 1
[0028] When the network forming atom is a silicon atom and the
polyvalent hydrocarbon group is a tervalent hydrocarbon group such
as a 1,2,3-propanetoluyl group, the silicon atom is bonded to other
silicon atoms through the 1,2,3-propanetoluyl group as shown in the
following formula (4). 2
[0029] Thus, the elasticity of the adhesive layer is increased and
the fragility of the adhesive layer is reduced by the above
structure that the network forming atom of the present invention is
bonded to other network forming atom(s) through a polyvalent
hydrocarbon group compared with a conventional structure that a
network forming atom is bonded to other network forming atom
through an oxygen atom, whereby a cohesive failure hardly occurs
and adhesion strength increases.
[0030] In the adhesive layer of the present invention, at least
part of the network forming atoms is directly bonded to at least
one monovalent hydrocarbon group selected from the group consisting
of an alkyl group, phenyl group, monovalent fluorine-containing
hydrocarbon group and monovalent sulfur-containing hydrocarbon
group. When the monovalent hydrocarbon group is existent in the
matrix comprising the network forming atoms and oxygen atoms, it
provides oxidation resistance, heat resistance and solvent
resistance to the matrix. Since the network forming atom in the
present invention has such a structure that it is bonded to other
network forming atom through the monovalent hydrocarbon group, an
adhesive material having excellent adhesion strength and
environmental resistance (heat resistance, weatherability, humidity
resistance and chemical resistance) can be provided.
[0031] When the amount of the polyvalent hydrocarbon group
contained in the adhesive layer is too large, the molecular weight
of a siloxane is reduced relatively and the viscosity of a liquid
composition lowers, thereby deteriorating coating work efficiency
and when the amount is too small, the effect of increasing the
adhesion strength of the adhesive layer is reduced, the molecular
weight of a siloxane increases relatively, and the viscosity of a
liquid composition becomes too high, thereby deteriorating coating
work efficiency. When the amount of the monovalent hydrocarbon
group contained in the adhesive layer is too large, adhesion to
glass lowers and when the amount is too small, the oxidation
resistance of the adhesive layer lowers. Therefore, the adhesive
layer contains the polyvalent hydrocarbon group and the monovalent
hydrocarbon group in amounts of preferably 0.01 to 30 wt % and 30
to 80 wt %, more preferably 0.02 to 20 wt % and 40 to 70 wt %,
respectively.
[0032] In the present invention, the each content of the network
forming atoms, the polyvalent hydrocarbon group and the monovalent
hydrocarbon group are adjusted such that the refractive index value
of the adhesive layer should approximate to the refractive index
values of the at least two optically transparent optical parts. In
concrete terms, when the refractive indices of two adjacent optical
parts are represented by n.sub.1 and n.sub.2 (with the proviso that
n.sub.1.gtoreq.n.sub.2), the adhesive layer between the adjacent
optical parts preferably has a refractive index n.sub.3 represented
by the following expression (1). The adhesive layer more preferably
has a refractive index n.sub.3 represented by the following
expression (2).
{square root}{square root over
((n.sub.1.multidot.n.sub.2))}-(({square root}{square root over
((n.sub.1.multidot.n.sub.2))}-n.sub.2)/3)-0.05.lto-
req.n.sub.3.ltoreq.{square root}{square root over
((n.sub.1.multidot.n.sub- .2))}+((n.sub.1-{square root}{square root
over ((n.sub.1n.sub.2))})/3)+0.0- 5 (1)
{square root}{square root over
((n.sub.1.multidot.n.sub.2))}-(({square root}{square root over
((n.sub.1.multidot.n.sub.2))}-n.sub.2)/4)-0.03.lto-
req.n.sub.3.ltoreq.{square root}{square root over
((n.sub.1.multidot.n.sub- .2))}+((n.sub.1-{square root}{square root
over ((n.sub.1n.sub.2))})/4)+0.0- 3 (2)
[0033] For example, when optical fibers are bonded to each other
and have a refractive index of 1.45,
1.40.ltoreq.n.sub.3.ltoreq.1.50 according to the above expression
(1) and 1.42.ltoreq.n.sub.3.ltoreq.1.48 according to the above
expression (2). An optical device having a small optical
propagation loss can be obtained by adjusting the refractive index
of the adhesive layer. As for optical parts other than optical
fibers, such as lenses, filters, optical waveguides, diffraction
gratings and optically active elements, an optical device having a
small optical propagation loss can be provided by adjusting the
refractive index.
[0034] The method of forming the adhesive layer of the present
invention will be described hereinafter.
[0035] Methods of forming a bond between the polyvalent hydrocarbon
group and two or more network forming atoms include one in which a
raw material compound having a polyvalent hydrocarbon group bonded
to two or more network forming atoms is used, one in which a metal
compound having a polymerizable reactive group directly bonded to a
metal compound is formed by thermal and/or optical polymerization,
and one in which the bond is formed by a hydrosililation reaction
between an alkenyl compound and a hydrogenated silicon compound.
The method in which a raw material compound having a polyvalent
hydrocarbon group bonded to two or more network forming atoms is
used is exemplified by one in which the raw material compound is
formed by hydrolysis and a dehydration condensation reaction among
bis(trialkoxysilyl)ethane, bis(trialkoxysilyl)propane and
bis(trialkoxysilyl)butane as raw materials. The method of forming
the metal compound by thermal and/or optical polymerization is
exemplified by one in which the metal compound is formed by mixing
an optically radical generating agent with vinyltrialkoxysilane or
vinyl both-terminated polydimethylsiloxane and polymerizing these
through optical exposure. The method of forming the bond by a
hydrosililation reaction between an alkenyl compound and a
hydrogenated silicon compound is exemplified by one in which the
bond is formed by a hydrosililation reaction between vinyl
both-terminated dimethylsiloxane and hydrogenated dimethylsiloxane
in the presence of a platinum catalyst. Out of these forming
methods, the method of forming the bond through a hydrosililation
reaction between an alkenyl compound and a hydrogenated silicon
compound is preferred because the heat resistance of the formed
adhesive layer is particularly excellent, the formation of bubbles
caused by a reaction by-product can be prevented and shrinkage in
the curing step is small.
[0036] Preferably, the adhesive composition for bonding optical
parts together comprises the following components (A) to (C):
[0037] (A) organopolysiloxane having at least two alkenyl groups
having 4 or less carbon atoms bonded to silicon atoms in the
molecule;
[0038] (B) organohydrogenpolysiloxane having at least two hydrogen
atoms bonded to silicon atoms in the molecule; and
[0039] (C) a platinum-based catalyst.
[0040] Examples of the organopolysiloxane compound having at least
two alkenyl groups having 4 or less carbon atoms bonded to silicon
atoms in the molecule (component (A)) include hydrogen terminated
polydimethylsiloxane compounds,
methylhydrogensiloxane-dimethylsiloxane copolymer compounds,
polymethylhydrogensiloxane compounds, polyethylhydrogensiloxane
compounds, polyphenyl(dimethylhydrogensiloxy)si- loxane hydrogen
terminated compounds, methylhydrogensiloxane-phenylmethyls- iloxane
copolymer compounds and methylhydrogensiloxane-octylmethylsiloxane
copolymer compounds having a vinyl group, vinyloxy group (2 carbon
atoms), allyl group, allyloxy group (3 carbon atoms), acryl group,
acryloxy group (2 carbon atoms), methacryl group or methacryloxy
group (3 carbon atoms). Out of these, both terminal vinyl group
dimethylsiloxane polymers represented by the following formula (5),
vinylmethylsiloxane-dimethylsiloxane copolymers represented by the
following formula (6), both terminal vinyl group
diphenylsiloxane-dimethy- lsiloxane copolymers represented by the
following formula (7) and both terminal vinyl group
methyltrimethylpropylsiloxanedimethylsiloxanes represented by the
following formula (8) are preferred. The component (A) preferably
has a viscosity of 100 to 250,000 cS at 25.degree. C. from the
viewpoint of coating work efficiency. 3
[0041] Examples of the organohydrogenpolysiloxane compound having
at least two hydrogen atoms bonded to silicon atoms in the molecule
(component (B)) include hydrogen terminated polydimethylsiloxane
compounds represented by the following formula (9),
methylhydrogensiloxane-dimethyl- siloxane copolymer compounds
represented by the following formula (10),
polyphenyl(dimethylhydrogensiloxane)siloxane hydrogen terminated
compounds represented by the following formula (11),
methyltrifluoropropylsiloxane(dimethylsiloxane)copolymer
represented by the following formula (12),
polymethylhydrogensiloxane compounds, polyethylhydrogensiloxane
compounds and methylhydrogensiloxane-phenylmeth- ylsiloxane
copolymer compounds. 4
[0042] Examples of the platinum-based catalyst (component (C)) used
in the adhesive composition of the present invention include a
platinum-siloxane complex, platinum-olefin complex,
platinum-(.beta.-diketone)complex, platinum-azo complex or the
like. Preferred examples of the catalyst include
platinum-carbonylvinylmethyl complex, platinum-divinyltetramethyl-
disiloxane complex, platinum-cyclovinylmethylsiloxane complex,
platinum-octylaldehyde/octanol complex and the like.
[0043] The contents of the component (A) and the component (B) in
the adhesive composition are desirably such that the number of the
hydrogen atoms contained in the component (B) is 0.4 to 6.0 times,
more preferably 0.6 to 4.0 times the total number of alkenyl groups
contained in the component (A). The above platinum-based catalyst
(component (C)) is preferably contained in an amount of 10 to 1,000
ppm based on the total weight of the component (A) and the
component (B) because appropriate curing speed is maintained and
appropriate pot life is achieved.
[0044] The adhesive composition of the present invention may
contain a tetraalkoxide (trialkoxide in the case of aluminum) of at
least one type of network forming atoms selected from the group
consisting of silicon, titanium, zirconium, aluminum and germanium
and a condensate of one or more of these metal alkoxides in small
quantities in addition to the above components (A) to (C). These
components cause the formation of bubbles and volume shrinkage
through dehydration or dealcoholation during the curing reaction of
the adhesive layer. The total content of these components may be 20
wt % or less based on the total weight of the adhesive
composition.
[0045] A description is subsequently given of the optical parts of
the present invention. Examples of the optical parts of the present
invention include optical fibers, lenses, filters, optical
waveguides, diffraction gratings and optical active elements. The
optical fibers include single-mode optical fibers and multi-mode
optical fibers. The lenses include refractive index distribution
lenses, spherical lenses, aspherical lenses and plano-convex
lenses. The optical filters include narrow-band filters composed of
a dielectric multi-layer film, band-pass filters and polarization
filters. The optical waveguides include single-mode optical
waveguides and multi-mode optical waveguides. These optical
waveguides may have a Bragg diffraction grating whose refractive
index is modulated periodically. The materials forming these
optical parts include glass materials, plastic materials and
organic-inorganic composite materials.
[0046] The materials forming the above optical parts preferably
have a linear expansion coefficient of 1.5.times.10.sup.-5/.degree.
C. or less. When the linear expansion coefficient of the base
material is higher than 1.5.times.10.sup.-5/.degree. C. like a
plastic optical part made from polypropylene having a high thermal
expansion coefficient (9 to 15.times.10.sup.-5/.degree. C.), an
optical part and an adhesive layer peel off at the interface or the
adhesive layer cracks in the heating step after the application of
the adhesive. General inorganic glass has a linear expansion
coefficient of 1.5.times.10.sup.-5/.degree. C. or less. At least
the bonded surface of an optical part is preferably made from an
oxide. When the bonded surface of an optical part is not made from
an oxide, adhesion strength lowers in the step of forming the
adhesive layer or the bonded surface and the adhesive layer peel
off at the interface as the case may be. Preferred examples of the
base material include oxide glasses such as silicate-based glass,
boric acid-based glass and phosphoric acid-based glass, quartz,
ceramics, epoxy resins, glass fiber reinforced polystyrene and the
like. The adhesive layer of the present invention is hardly bonded
to a metal as it is but when the surface of the metal is treated
with an oxidizing agent, the metal can be used as a part to be
bonded.
[0047] To assemble these optical parts, the optically transparent
adhesive composition of the present invention is placed, filled or
spread out between a first optical part and a second optical part
and cured to form a bonded portion having predetermined strength.
As for the curing of the adhesive, an adhesive composition which is
cured in a few minutes can be obtained by increasing the amount of
a curing catalyst and an adhesive composition having a pot life of
a few hours can be obtained by reducing the amount of a curing
catalyst. The curing time can be shortened by carrying out a heat
treatment as required. A reaction retardant or curing accelerator
may be added in an amount of 40 wt % or less, preferably 30 wt % or
less as required. The curing time can be freely controlled by
adding a reaction retardant and curing accelerator.
[0048] Examples are given below to further illustrate the present
invention.
EXAMPLES
Preparation of First Raw Materials (Raw Materials A to I)
[0049] (Raw Material A)
[0050] 0.039 mol (5 g) of dimethyldichlorosilane, 4 mols (72 g) of
water and 1 mol (120.6 g) of dimethylvinylchlorosilane were mixed
together and reacted with one another at 60.degree. C. for 2 hours.
Water and unreacted dimethylvinylchlorosilane were removed from the
reaction mixture under reduced pressure and the reaction mixture
was dehydrated to obtain terminal vinyl polydimethylsiloxane
(viscosity: 1,000 cS, molecular weight: 28,000, content of vinyl
group: 0.18 to 0.26 wt %) (raw material A).
[0051] (Raw Material B)
[0052] 1 mol (253.13 g) of diphenyldichlorosilane, 1 mol (129.3 g)
of dimethyldichlorosilane, 4 mols (72 g) of water and 1 mol (120.6
g) of dimethylvinylchlorosilane were mixed together and reacted
with one another at 60.degree. C. for 2 hours. Water and unreacted
dimethylvinylchlorosilane were removed from the reaction mixture
under reduced pressure and the reaction mixture was dehydrated to
obtain a vinyl terminated diphenylsiloxane-dimethylsiloxane
copolymer (viscosity: 500 cS, molecular weight: 9,500, content of
phenyl group: 18 to 22 wt %, content of vinyl group: 0.37 to 0.42
wt %) (raw material B).
[0053] (Raw Material C)
[0054] 1 mol of methyltrifluoropropyldichlorosilane, 1 mol of
dimethyldichlorosilane, 4 mols of water and 1 mol of
dimethylvinylchlorosilane were mixed together and reacted with one
another at 60.degree. C. for 2 hours. Water and unreacted
dimethylvinylchlorosilane were removed from the reaction mixture
under reduced pressure and the reaction mixture was dehydrated to
obtain a vinyl terminated
methyltrifluoropropylsiloxane-dimethylsiloxane copolymer
(viscosity: 500 cS, molecular weight: 9,500) (raw material C).
[0055] (Raw Material D)
[0056] 5 g (0.0676 mol) of ethanol and 0.01 mol of an aqueous
solution of hydrochloric acid containing 10 mols of water were
added to 5 g (0.0240 mol) of tetraethoxysilane and stirred at room
temperature for 2 hours. 11.58 g (0.096 mol) of
dimethylvinylchlorosilane which was 4 molar equivalents of
tetraethoxysilane was added to the resulting solution to carry out
a reaction at 60.degree. C. for 2 hours. Ethanol, water and
unreacted dimethylvinylchlorosilane were removed from the reaction
mixture under reduced pressure and the reaction mixture was
dehydrated to obtain an equivalent to the Vinyl Q Resin (of Guerest
Co., Ltd., viscosity of 5,000 cS) (raw material D).
[0057] (Raw Material E)
[0058] 1.89 g (0.0189 mol) of acetylacetone, 5 g of isopropanol and
0.01 mol of an aqueous solution of hydrochloric acid containing 4
mols of water were added to 5 g (0.0189 mol) of
tetraisopropoxytitanium and stirred at room temperature for 2
hours. 9.12 g (0.0756 mol) of dimethylvinylchlorosilane which was 4
molar equivalents of tetraisopropoxytitanium was added to the
resulting solution to carry out a reaction at 60.degree. C. for 2
hours. Isopropanol, acetylacetone, water and unreacted
dimethylvinylchlorosilane were removed from the reaction mixture
under reduced pressure to obtain a vinyl terminated titanium oxide
condensate (raw material E).
[0059] (Raw Material F)
[0060] 2 molar equivalents of acetylacetone, 5 g of butanol and
0.01 mol of an aqueous solution of hydrochloric acid containing 4
molar equivalents of water were added to 5 g (0.0130 mol) of
tetrabutoxyzirconium and stirred at room temperature for 2 hours.
6.27 g (0.052 mol) of dimethylvinylchlorosilane which was 4 molar
equivalents of tetrabutoxyzirconium was added to the resulting
solution to carry out a reaction at 60.degree. C. for 2 hours.
Isopropanol, acetylacetone, water and unreacted
dimethylvinylchlorosilane were removed from the reaction mixture
under reduced pressure to obtain a vinyl terminated zirconium oxide
condensate (raw material F).
[0061] (Raw Material G)
[0062] 1 molar equivalent of acetylacetone, 5 g of butanol and 0.01
mol of an aqueous solution of hydrochloric acid containing 4 molar
equivalents of water were added to 5 g (0.0183 mol) of
tri-sec-butoxyaluminum and stirred at room temperature for 2 hours.
8.83 g (0.0732 mol) of dimethylvinylchlorosilane which was 4 molar
equivalents of tri-sec-butoxyaluminum was added to the resulting
solution to carry out a reaction at 60.degree. C. for 2 hours.
Isopropanol, acetylacetone, water and unreacted
dimethylvinylchlorosilane were removed from the reaction mixture
under reduced pressure to obtain a vinyl terminated aluminum oxide
condensate (raw material G).
[0063] (Raw Material H)
[0064] 2 molar equivalents of water and 8.10 g (0.0672 mol) of
dimethylvinylchlorosilane were added to 5 g (0.0168 mol) of
diphenyldichlorogermanium to carry out a reaction at 60.degree. C.
for 2 hours. Water and unreacted dimethylvinylchlorosilane were
removed from the reaction mixture under reduced pressure to obtain
a vinyl terminated germanium oxide condensate (raw material H).
[0065] (Raw Material I)
[0066] Raw material I was prepared in the same manner as in the
preparation of raw material A except that 1 mol of
allyldimethylchlorosilane was used in place of 1 mol of
dimethylvinylchlorosilane used for the preparation of raw material
A.
Optical Part
[0067] (Optical Fiber)
[0068] A glass single-mode optical fiber (clad diameter: 120 .mu.m,
core diameter: 10 .mu.m, refractive index of core: 1.46, refractive
index of clad: 1.44) was prepared.
[0069] (Lens)
[0070] A glass microlens (Selfoc Microlens SMC18, diameter: 1.8 mm,
length: 4.43 mm (0.23 pitch, refractive index of center portion:
1.590, distribution coefficient g=0.326, 1 pitch (=2 .pi./g)=19.27
mm) was prepared.
[0071] (Filter)
[0072] A bandpass filter was prepared by laminating a silicon oxide
layer (refractive index: 1.46) and a titanium oxide layer
(refractive index: 2.1) on one side of a glass substrate
(refractive index: 1.46) alternately.
[0073] (Optical Waveguide)
[0074] An optically radical forming agent was added in an amount of
3 wt % based on the total weight to a liquid composition obtained
by mixing together a silica raw material solution obtained by
hydrolyzing acryloxypropyltrimethoxysilane with 0.1N hydrochloric
acid and a zirconia raw material obtained by treating zirconium
tetrabutoxide with an equimolar amount of acrylic acid in a Si/Zr
ratio of 1:1 to obtain a solution for forming an optical waveguide.
This solution was applied to a silicon substrate having a 8
.mu.m-thick silica film (V-shaped groove for fixing an optical
fiber was formed in an end portion thereof) by spin coating and
heated at 80.degree. C. for 10 minutes and a waveguide portion was
exposed to light by a high-pressure mercury lamp (at 10 mW for 15
seconds) through a photomask. Unexposed portions were dissolved in
isopropanol and removed. A liquid composition whose Si/Zr ratio was
adjusted to 1.2:1 was coated on the substrate and dried to obtain
an embedded waveguide.
[0075] (Waveguide Type Diffraction Grating)
[0076] A Bragg grating was formed on the above optical waveguide by
a double-beam interference exposure method to obtain a waveguide
type diffraction grating.
[0077] The refractive index values at related sites of the above
optical parts are shown in Table 1.
1 TABLE 1 optical part refractive index optical fiber (core) 1.45
lens (center portion) 1.590 optical waveguide (core) 1.52 optical
filter 1.46
Preparation of Adhesive Compositions
[0078] As shown in Table 2, methylhydrogensiloxane-dimethylsiloxane
copolymer J (viscosity: 25 to 35 cS, molecular weight: 2,000) or
methylhydrogensiloxane-phenylmethylsiloxane copolymer K (viscosity:
100 cS) (copolymer J or K will be referred to as "second raw
material" hereinafter) was added to the first raw material to
ensure that the number of hydrogen atoms contained in the second
raw material should be 0.4 to 6.0 times the total number of alkenyl
groups contained in the above first raw material and a platinum
catalyst (platinum-divinyltetrame- thyldisiloxane complex) was
mixed in an amount of 100 ppm based on the total to obtain adhesive
compositions (1) to (17).
2TABLE 2 adhesive second raw adhesive first raw material material
ratio of number of composition quantity quantity quantity hydrogen
atoms to total No. type (g) type (g) type (g) number of alkenyl
groups 1 A 0.5 -- -- J 0.01 1.5 2 B 0.6 -- -- J 0.01 1.5 3 C 0.5 --
-- J 0.01 1.5 4 D 0.4 -- -- J 0.01 1.5 5 E 0.4 -- -- J 0.01 1.5 6 F
0.4 -- -- J 0.01 1.5 7 G 0.5 -- -- J 0.01 1.5 8 H 0.4 -- -- J 0.01
1.5 9 A 0.26 B 0.14 J 0.01 1.5 10 A 0.08 B 0.32 K 0.01 2.0 11 B
0.16 C 0.24 J 0.01 1.5 12 B 0.28 D 0.12 J 0.01 1.5 13 A 0.16 E 0.24
J 0.01 1.5 14 A 0.16 F 0.24 J 0.01 1.5 15 A 0.2 G 0.20 J 0.01 1.5
16 A 0.32 H 0.08 J 0.01 1.5 17 I 0.40 -- -- J 0.01 1.5
[0079] 10 mg of each of the above adhesive compositions (1) to (17)
was dropped onto a first slide glass (25 mm.times.50 mm.times.1.2
mm), a second slide glass was placed upon the first slide glass to
spread the adhesive composition to a size of 25 mm.times.25 mm, and
the adhesive composition was then heated on a hot plate at
200.degree. C. for 15 minutes. The appearance of the adhesive layer
between the first and second glasses was observed to check the
formation of air bubbles and the cloudiness of the layer. 1 g of
the adhesive composition was placed in a 3 ml glass sample bottle
and heated at 200.degree. C. for 30 minutes to measure the volume
of the adhesive composition before and after the heat treatment to
evaluate a volume shrinkage factor (%) represented by 100.times.
(volume before heating-volume after heating)/(volume before
heating). To evaluate the adhesion strength (cohesive failure rate)
of the adhesive layer, the glass plates on both sides of the
adhesive layer were pulled in opposite directions at a rate of 50
cm/min to measure adhesion (shear) strength (N/mm.sup.2). The
results are shown in Table 3. In Examples (adhesive compositions
(1) to (17)), the formation of bubbles was not observed during the
heat treatment, volume shrinkage was very small, and adhesion
strength was sufficient. Rupture did not occur at the interface
between the adhesive layer after an adhesion strength test and
glass but was seen in the interior of the adhesive layer.
Comparative Example 1
[0080] 1.33 ml of polydimethylsiloxane (PDMS), 35.6 ml of
methyltriethoxysilane (MTES) and 2.67 ml of phenyltrifluorosilane
(PTFS) were injected into a 100 ml sample tube (molar ratio of
8:83:9) and stirred at room temperature for 5 minutes by covering
the tube. The mixture was heated at 70.degree. C., and 5.4 g of
water was added and strongly stirred for 30 minutes. The reaction
mixture was separated into two layers at first but became uniform
after that. By removing the cover, the reaction mixture was left in
the atmosphere for 1 day and the solvent was naturally dried to
obtain an adhesive composition (18). The formation of bubbles
during the heat treatment, volume shrinkage and adhesion strength
of this adhesive composition were measured in the same manner as
the above adhesive compositions (1 to 17). The results are shown in
Table 3. Bubbles were formed during the heat treatment and air
bubbles continuous from the center to the end portions of glass
were formed in the adhesive composition (18) shown as Comparative
Example. Along with the generation of gas, volume shrinkage was
observed and adhesion strength was not sufficient. Rupture did not
occur at the interface between the adhesive layer after the
adhesion strength test and glass but the rupture of the interior of
the adhesive layer and the rupture of the adhesive layer itself
caused by the existence of bubbles in the adhesive layer were
observed. The formation of bubbles made the adhesive layer cloudy,
impaired the light transmission of the adhesive layer and increased
the light transmission loss of the bonded optical part. The volume
shrinkage of the adhesive layer changed the distance between
optical parts to be bonded together (shift in focusing point when a
lens and other optical part are bonded together), thereby causing a
light transmission loss or internal distortion in the adhesive
layer or cracking the adhesive layer. As a result, the optical
properties of the optical parts are apt to deteriorate.
3TABLE 3 adhesive layer content of content of polyvalent monovalent
adhesive hydrocarbon hydrocarbon appearance of glass shrinkage
adhesion composition group group refractive adhesive factor
strength No. (wt %) (wt %) index bubbles cloudiness (%)
(N/mm.sup.2) 1 0.2 40 1.42 none none less than 0.1 2.3 2 0.2 45
1.55 none none less than 0.1 2.4 3 0.2 45 1.39 none none less than
0.1 2.2 4 3.0 35 1.43 none none less than 0.1 2.1 5 5.0 40 1.60
none none less than 0.1 2.2 6 3.0 40 1.58 none none less than 0.1
2.3 7 2.0 30 1.57 none none less than 0.1 2.1 8 0.5 50 1.59 none
none less than 0.1 2.0 9 0.2 40 1.46 none none less than 0.1 2.2 10
0.2 45 1.52 none none less than 0.1 2.3 11 0.2 45 1.49 none none
less than 0.1 2.1 12 0.2 45 1.46 none none less than 0.1 2.3 13 0.2
45 1.53 none none less than 0.1 2.1 14 0.2 45 1.53 none none less
than 0.1 2.2 15 0.2 45 1.49 none none less than 0.1 2.2 16 0.2 45
1.46 none none less than 0.1 2.1 17 0.2 45 1.40 none none less than
0.1 2.1 18 -- -- 1.43 yes yes 60 0.3
Examples 1 to 3
[0081] (Bonding Optical Fiber to Optical Fiber)
[0082] As shown in FIG. 1, a polymer coated layer 4 was removed
from 2 cm end portions of first and second single-mode glass
optical fibers 1 and 21 (each length of about 1 m), each having a
polymer coated layer 4, core portion 2 and clad portion 3, and
these end portions were butted against each other on an optical
bench (not shown) through an about 25 .mu.m long air gap to align
the centers of the optical fibers 1 and 21 with each other. The
locations of the fibers were adjusted such that the optical loss
value when laser light having a wavelength of 1,550 nm was input
from the other end portion of the first optical fiber, transmitted
through the first fiber and output from the other end portion of
the second fiber became minimum. In this state, the adhesive 5 in
the figure (adhesive composition numbers 1, 4 and 9) was coated at
the position of the air gap between the two fibers and cured by
leaving it at room temperature for 2 hours or by heating coated
portions with 110.degree. C. hot air from a drier for about 5
minutes. The initial optical loss value before the coating of the
adhesive and the optical loss value after the adhesive composition
was coated and cured were measured and compared with each other (1
to 3 of Table 4).
Examples 4 to 6
[0083] (Bonding Lens to Lens)
[0084] As shown in FIG. 2, one end portions of first and second
single-mode glass optical fibers (length of about 1 mm, polymer
coated layer 4 was removed from one ends thereof) 1 and 12, each
having a polymer coated layer. 4, core portion 2 and clad portion
3, were bonded to one end portions of the above two glass
microlenses 6 and 26 (Selfoc Microlens SMC18) by an adhesive 25,
respectively. The other end portions of the microlenses 6 and 26
were opposed to each other, the centers thereof were aligned with
each other on an optical bench (not shown), and the locations of
the lenses were adjusted such that the optical loss value when
laser light having a wavelength of 1,550 nm was input from the
other end of the optical fiber 1, transmitted through the first
microlens 6 and the second microlens 26 through an about 250 .mu.m
air gap and output from the other end of the optical fiber 21
became minimum. In this state, the adhesive 5 in the figure
(adhesive composition numbers 6, 5 and 8) was coated between the
two lenses 6 and 26 and cured at room temperature for 2 hours or by
heating with 110.degree. C. hot air from a drier for about 5
minutes. The initial optical loss value (before the coating of the
adhesive) and the optical loss value after the coating and curing
of the adhesive were measured and compared with each other (4 to 6
of Table 4).
Examples 7 to 9
[0085] (Bonding Lens to Optical Fiber, Fabrication of Collimator
Module)
[0086] As shown in FIG. 3, one end portion of the optical fiber 1
was inserted into a glass ferrule 7 so that the optical fiber 1 was
fixed in a recessed portion of the end portion of the ferrule 7
using an adhesive 25. The center of the ferrule with this fiber and
the center of the glass microlens 6 were aligned with each other on
an optical bench so that the optical loss value when laser light
having a wavelength of 1,550 nm was input from the other end
portion of the optical fiber 1 fixed to the ferrule, transmitted
through the microlens 6 through an about 250 .mu.m air gap and
output to the outside through the microlens 6 became minimum, the
adhesive 5 in the figure (adhesive composition numbers 10, 13 and
14) was coated between the lens 6 and the ferrule 7 and cured at
room temperature for 2 hours or by heating with 110.degree. C. hot
air from a drier to manufacture a collimator module. The initial
optical loss value (before the coating of the adhesive) and the
optical loss value after the coating and curing of the adhesive
were measured and compared with each other (7 to 9 of Table 4).
Examples 10 to 12
[0087] (Bonding Lens to Filter)
[0088] A lens and a filter were bonded together in the same manner
as in Examples (4 to 6) for bonding lens to lens as shown in FIG. 4
except that a lens with a filter prepared by bonding the above
filter 8 and the above lens 6 together was used in place of the
first lens and that the adhesive 5 (adhesive composition numbers 7,
2 and 12) was used in place of the adhesive 5 (adhesive numbers 6,
5 and 8) (10 to 12 of Table 4).
Examples 13 and 14
[0089] (Bonding Fiber to Optical Waveguide)
[0090] As shown in FIG. 5, a polymer coated layer 4 was removed
from a 2 cm end portion of the above single-mode glass optical
fiber 1 (length of about 1 m) having a polymer coated layer 4, core
portion 2 and clad portion 3, and fixed on a V-shaped groove of a
waveguide by an adhesive 11, and the end portion was butted against
the end portion of the optical waveguide core 9 of the above
optical waveguide element 14 having a core 9 and a clad 10 through
an about 25 .mu.m long air gap to align centers thereof with each
other. The location of the optical fiber 1 was adjusted such that
the optical loss value when laser light having a wavelength of
1,550 nm was input from the other end portion of the optical fiber,
transmitted through the fiber and output from the other end portion
of the core of the optical waveguide became minimum, and the
adhesive 5 in the figure (adhesive composition numbers 11 and 15)
was coated at the position of the air gap between the end surface
of the optical fiber 1 and the end surface of the core 9 of the
optical waveguide and cured by leaving at room temperature for 2
hours or by heating coated portions with 110.degree. C. hot air
from a drier for abut 5 minutes. The initial optical loss value
before the coating of the adhesive and the optical loss value after
the coating and curing of the adhesive composition were measured
and compared with each other (13 and 14 of Table 4).
Example 15
[0091] (Bonding Fiber to Optical Waveguide Diffraction Grating)
[0092] An optical fiber and an optical waveguide diffraction
grating were bonded together in the same manner as in Examples 13
and 14 except that the above waveguide diffraction grating was used
in place of the optical waveguide element used in Examples 13 and
14 and the adhesive 5 (adhesive composition number 16) was used in
place of the adhesive 5 (adhesive composition numbers 11 and 15)
used in Examples 13 and 14 and the optical loss values were
measured in the same manner as in Examples 4 to 6. The results are
shown in 15 of Table 4.
Example 16
[0093] Lenses were bonded together in the same manner as in
Examples 4 to 6 except that the adhesive 5 (adhesive composition
number 4) was charged into a space between the lenses 6 and 26 and
the ferrule 12 as shown in FIG. 6 instead that the adhesive
composition 5 was coated between the lenses 6 and 26. The optical
loss values were completely the same as those of Example 4.
4TABLE 4 adhesive output during output after composition existence
of air curing of Ex. first optical part second optical part No. gap
(dB .multidot. m) adhesive (dB .multidot. m) 1 optical fiber
optical fiber 1 11.50 11.16 2 optical fiber optical fiber 4 11.50
11.20 3 optical fiber optical fiber 9 11.50 11.12 4 lens lens 6
11.00 10.10 5 lens lens 5 11.00 10.00 6 lens lens 8 11.00 10.20 7
lens optical fiber 10 11.70 11.30 8 lens optical fiber 13 11.70
11.20 9 lens optical fiber 14 11.70 11.40 10 lens optical filter 7
20.40 19.20 11 lens optical filter 2 20.40 19.60 12 lens optical
filter 12 20.40 19.40 13 optical fiber optical waveguide 11 15.1
14.80 14 optical fiber optical waveguide 15 15.10 14.70 15 optical
fiber optical waveguide 16 15.10 14.80 diffraction grating Ex.:
Example
[0094] As described above, according to the present invention, an
optical device comprising optical parts bonded together with an
adhesive layer having excellent adhesion strength, a small light
transmission loss and excellent environmental resistance (heat
resistance, weatherability, humidity resistance and chemical
resistance) is obtained by preventing the generation of gas and
shrinkage in the adhesive curing step.
* * * * *