U.S. patent application number 09/926827 was filed with the patent office on 2002-09-26 for transparent optical article.
Invention is credited to Oka, Koichiro, Okamoto, Masahiko.
Application Number | 20020136897 09/926827 |
Document ID | / |
Family ID | 18642252 |
Filed Date | 2002-09-26 |
United States Patent
Application |
20020136897 |
Kind Code |
A1 |
Okamoto, Masahiko ; et
al. |
September 26, 2002 |
TRANSPARENT OPTICAL ARTICLE
Abstract
The invention has an object to obtain a polarizing and dimming
transparent optical product having both a polarizing function and a
dimming function, for example, polarizing and dimming sunglasses,
goggles and lenses. The transparent optical product according to
the invention has a lamination structure including one polarizer
sheet layer, and at least one layer other than the polarizer sheet
having the dimming function. Moreover, a plurality of sheets
including one polarizer sheet and at least one sheet other than the
polarizer sheet are mutually bonded with an adhesive or a binder to
constitute a composite sheet, and at least one of the non-polarizer
sheets and adhesive or binder layers in the composite sheet has the
dimming function.
Inventors: |
Okamoto, Masahiko; (Osaka,
JP) ; Oka, Koichiro; (Osaka, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Family ID: |
18642252 |
Appl. No.: |
09/926827 |
Filed: |
December 27, 2001 |
PCT Filed: |
April 23, 2001 |
PCT NO: |
PCT/JP01/03477 |
Current U.S.
Class: |
428/411.1 ;
428/412 |
Current CPC
Class: |
G02C 7/12 20130101; B32B
7/12 20130101; Y10T 428/31507 20150401; G02B 5/3041 20130101; B32B
7/023 20190101; Y10T 428/31504 20150401 |
Class at
Publication: |
428/411.1 ;
428/412 |
International
Class: |
B32B 009/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 2, 2000 |
JP |
2000-133845 |
Claims
1. A transparent optical product of a lamination structure
including one polarizer sheet layer, wherein at least one layer
other than the polarizer sheet has a dimming function.
2. A transparent optical product of a plurality of sheets
comprising one polarizer sheet layer and at least one other sheet
layer which are mutually bonded with an adhesive or a binder to
constitute a composite sheet, wherein at least one of the other
sheet layer and adhesive or binder layer in the composite sheet has
a dimming function.
3. A transparent optical product of three or more sheets, one inner
layer being a polarizer sheet and the other layers being
non-polarizer sheets, which are mutually bonded with an adhesive or
a binder to constitute a composite sheet, wherein at least one of
the other layers and adhesive or binder layers in the composite
sheet has a dimming function.
4. The transparent optical product according to claim 2 or 3,
wherein both outermost sheet layers of the composite sheet are
formed of resins of the same structure.
5. A transparent optical product having a composite sheet and a
resin layer laminated to each other, the composite sheet comprising
one polarizer sheet layer and at least one other sheet layer which
are mutually bonded with an adhesive or a binder, one of outermost
layers of the composite sheet being integrated with the resin layer
by a thermal molding method, at least one of the other sheet layer,
adhesive or binder layer, and the resin layer having a dimming
function.
6. A transparent optical product having a composite sheet and a
resin layer laminated to each other, the composite sheet comprising
three or more layers including one inner layer of a polarizer sheet
and the other layers of non-polarizer sheets which are mutually
bonded with an adhesive or a binder, one of outermost layers of the
composite sheet being integrated with the resin layer by a thermal
molding method, at least one of the other sheet layers, adhesive or
binder layers, and resin layer having a dimming function.
7. The transparent optical product according to claim 5 or 6,
wherein both of the outermost layers of the composite sheet are
formed of resins of the same structure.
8. The transparent optical product according to any of claims 5 to
7, wherein one of the outermost layers of the composite sheet is
integrated with the resin layer by an injection compression molding
method for the resin layer.
9. The transparent optical product according to any of claims 2 to
4, wherein at least one of the outermost layers of the composite
sheet is formed of a polycarbonate based resin.
10. The transparent optical product according to claim 9, wherein
the polycarbonate based resin has a mean polymerization degree of
120 or less.
11. The transparent optical product according to any of claims 5 to
8, wherein one of the outermost layers of the composite sheet and
the resin layer are formed of a polycarbonate based resin.
12. The transparent optical product according to claim 11, wherein
the polycarbonate based resin has a mean polymerization degree of
120 or less.
13. The transparent optical product according to any of claims 2 to
4, wherein at least one of the outermost layers of the composite
sheet is formed of a resin having a modulus of photoelasticity of
30.times.10.sup.-13 cm.sup.2/dyne or less and a glass transition
temperature of 85.degree. C. or more.
14. The transparent optical product according to any of claims 5 to
8, wherein one of the outermost layers of the composite sheet and
the resin layer are formed of a resin having a modulus of
photoelasticity of 30.times.10.sup.-13 cm.sup.2/dyne or less and a
glass transition temperature of 85.degree. C. or more.
15. The transparent optical product according to any of claims 5 to
8, 11, 12 or 13, wherein a thickness x of the composite sheet and a
thickness y of the resin layer have a relationship of
100.gtoreq.y/x.gtoreq.0.3 in every portion within a range of a 35
mm radius from the center of the transparent optical product.
16. The transparent optical product according to any of claims 1 to
15, wherein a portion inside of the surface or a surface portion of
at least one of the outermost layers is processed to provide a
dimming function.
Description
TECHNICAL FIELD
[0001] The present invention relates to a transparent optical
product to be used for sunglasses, goggles or lenses.
BACKGROUND ART
[0002] Assuming-an oscillation component of light in a plane
including directions of an incident light and a normal as a p
polarization and an oscillation component of light in a plane
perpendicular thereto as an s polarization, light reflected by a
glossy surface such as a glass or water surface has a minimum point
where the s polarization is monotonously increased with respect to
an angle of reflection and the p component is almost zero in the
vicinity of 60 degrees. By using a polarizing filter for cutting
the s polarization and transmitting only the p polarization,
accordingly, it is possible to considerably reduce a dazzling
feeling caused by the reflected light. There have been known
sunglasses, ski goggles and corrective lenses which have a
polarizer in order to relieve a dazzlement caused by the reflected
light of the surface of the water, a snowy surface, a road, a
windowpane or a metallic surface and to give easiness to see by
using the principle.
[0003] Moreover, there have been known transparent optical products
having a dimming and shielding function formed by kneading a
dimming dye (a photochromic dye) into a lens base material or
coating the surfaces of lenses with a coating agent containing the
dyes, which provide sunglasses, ski goggles or corrective lenses
with a dimming function and a shielding function by carrying out
coloring under external light including a large number of
ultraviolet rays and uncoloring under artificial rays having a
small number of ultraviolet rays.
[0004] However, there has not conventionally been a practical
transparent optical product having a high functionality which has
both a polarizing function and a dimming function, prevents a
dazzlement from being caused by reflected light and properly
changes a light shielding property corresponding to the intensity
of external light. A technique for inexpensively providing such a
transparent optical product having a high functionality has been
desired.
[0005] In consideration of the problems described above, the
invention can inexpensively provide a transparent optical product
having a high functionality which comprises both a polarizing
function and a dimming function, prevents a dazzlement from being
caused by reflected light and properly changes a light shielding
property corresponding to the intensity of external light.
DISCLOSURE OF THE INVENTION
[0006] Technical aspect according to the invention to solve the
technological problems described above is a transparent optical
product having a lamination structure including one polarizer
sheet, wherein at least one of layers other than the polarizer
sheet has a dimming function.
[0007] Another technical aspect according to the invention is that
a plurality of sheets comprising one layer polarizer sheet and at
least one layer other than the polarizer sheets are mutually bonded
with an adhesive or a binder to constitute a composite sheet and at
least one of the non-polarizer sheets, adhesive layer or binder
layer in the composite sheet has a dimming function.
[0008] Yet another technical aspect according to the invention is
that three or more layers, one inner layer being a polarizer sheet
and the rest not being polarizer sheets, are mutually bonded with
an adhesive or a binder to constitute a composite sheet and at
least one of the non-polarizer sheets, adhesive layer or binder
layer in the composite sheet has a dimming function.
[0009] Further technical means according to the invention is that
both outermost sheets of the composite sheet are formed of resins
of the same structure.
[0010] Further technical aspect according to the invention is a
transparent optical product having a composite sheet and a resin
layer laminated, wherein a plurality of sheets including one
polarizer sheet layer and at least one non-polarizer sheet layer
are mutually bonded with an adhesive or a binder to constitute the
composite sheet, one of outermost layers of the composite sheet and
the resin layer are integrated by a thermal molding method, and at
least one of the non-polarizer sheets, adhesive or binder layer and
the resin layer has a dimming function.
[0011] Further technical aspect according to the invention is a
transparent optical product having a composite sheet and a resin
layer laminated, wherein three or more layers, one inner layer
being a polarizer sheet and the rest not being polarizer sheets,
are mutually bonded with an adhesive or a binder to constitute the
composite sheet, one of outermost layers of the composite sheet and
the resin layer are integrated by a thermal molding method, and at
least one of the non-polarizer sheet layers, adhesive or binder
layers and the resin layer has a dimming function.
[0012] Further technical aspect according to the invention is that
both of the outermost sheets of the composite sheet are formed of
resins of the same structure.
[0013] Further technical aspect according to the invention is that
one of the outermost sheets of the composite sheet and the resin
layer are integrated by an injection compression molding method for
the resin layer.
[0014] Further technical aspect according to the invention is that
at least one of the outermost sheets of the composite sheet is
formed of a polycarbonate based resin.
[0015] Further technical aspect according to the invention is that
the polycarbonate based resin has a mean polymerization degree of
100 or less.
[0016] Further technical aspect according to the invention is that
one of the outermost sheets of the composite sheet and the resin
layer are formed of a polycarbonate based resin.
[0017] Further technical aspect according to the invention is that
the polycarbonate based resin has a mean polymerization degree of
120 or less.
[0018] Further technical aspect according to the invention is that
at least one of the outermost layers of the composite sheet is
formed of a resin having a modulus of photoelasticity of
30.times.10.sup.--13 cm.sup.2/dyne or less and a glass transition
temperature of 85.degree. C. or more.
[0019] Further technical aspect according to the invention is that
one of the outermost sheets of the composite sheet and the resin
layer are formed of a resin having a modulus of photoelasticity of
30.times.10.sup.--13 cm.sup.2/dyne or less and a glass transition
temperature of 85.degree. C. or more.
[0020] Further technical aspect according to the invention is that
a thickness x of the composite sheet and a thickness y of the resin
layer have a relationship of 100.gtoreq.y/x.gtoreq.0.3 in every
portion within a range of a 35 mm radius from the center of the
transparent optical product.
[0021] Further technical aspect according to the invention is that
an inside surface or surface portion of at least one of the
outermost layers of the transparent optical product is processed to
provide a dimming function.
BEST MODE OF CARRYING OUT THE INVENTION
[0022] The layer structure of a transparent optical product
according to the invention will be described. The transparent
optical product according to the invention is constituted in a
multilayer structure including one polarizer sheet layer, and at
least one sheet layer other than the polarizer sheet has a dimming
function.
[0023] A specific embodiment according to the invention comprises
one polarizer sheet layer and at least one non-polarizer sheet
layer which are mutually bonded with an adhesive or a binder to
constitute a composite sheet (hereinafter referred to as a
"composite sheet A" for convenience), and at least one of the
non-polarizer sheet layers and adhesive or binder layers has the
dimming function.
[0024] Specifically, the composite sheet A is constituted by
mutually bonding one polarizer sheet layer and one non-polarizer
sheet layer with an adhesive or a binder, and at least one of the
non-polarizer sheet layer and adhesive or binder layer has the
dimming function.
[0025] More specifically, the composite sheet A comprises three
sheets, central layer being a polarizer sheet, mutually bonded with
an adhesive or a binder, and at least one of the non-polarizer
sheet layers and adhesive or binder layers has the dimming
function. Such a case is one of the most recommended embodiments
according to the invention in that the effects of the invention can
be sufficiently embodied inexpensively. In particular, where both
of two other sheet layers provided as outermost layers are formed
of a resin having the same structure, no curl is generated because
symmetry in the sectional direction of the composite sheet A can be
taken easily, so that the composite sheet A having an excellent
plane property can be obtained easily. Moreover, if sheets having
different mechanical or optical performances are combined, the
performance of the transparent optical product can be enhanced.
[0026] More specifically, the composite sheet A comprises four or
more layers as a whole, one inner layer is a polarizer sheet, the
rest three or more layers of non-polarizer sheets which interpose
at least the polarizer sheet and are mutually bonded with an
adhesive or a binder, and at least one of the non-polarizer sheet
layers and adhesive or binder layers has the dimming function. In
this case, all non-polarizer sheets may be resin sheets of the same
structure. Alternatively, the performance of the transparent
optical product can be enhanced by using sheets having different
mechanical or optical performances as some of the sheets.
[0027] These transparent optical products usually have planar
structures at an adhering or binding stage and are formed into
curved structures having spherical surfaces, curved surfaces or the
like for processing them into finished products.
[0028] Another embodiment according to the invention is a
transparent optical product comprising a composite sheet
(hereinafter referred to as a "composite sheet B" for convenience)
including one polarizer sheet layer and at least one non-polarizer
sheet layer which are mutually bonded with an adhesive or a binder,
and a resin layer, wherein one outermost layer of the composite
sheet B and the resin layer are integrated by a thermal molding
method, and at least one of the non-polarizer sheet layer, adhesive
or binder layer, and the resin layer has a dimming function.
[0029] More specifically, the transparent optical product may
comprise the composite sheet B including three sheets, a central
layer being a polarizer sheet mutually bonded with an adhesive or a
binder, and a resin layer, wherein one of outermost layers of the
composite sheet B and the resin layer are integrated by the thermal
molding method, and at least one of the non-polarizer sheet layers,
adhesive or binder layers, and the resin layer has the dimming
function. Such a case is one of the most recommended embodiments
according to the invention in that the effects according to the
invention can be sufficiently embodied inexpensively. In
particular, where both of two non-polarizer sheets provided as the
outermost layers of the composite sheet B are formed of a resin
having the same structure, no curl is generated because symmetry in
the sectional direction of the composite sheet B can be taken
easily, so that the composite sheet B having an excellent plane
property can be obtained easily, which is advantageous to a
workability in an after-processing. Moreover, it is also possible
to combine sheets having different mechanical or optical
performances.
[0030] More specifically, the transparent optical product may
comprise the composite sheet B including four or more layers as a
whole, one inner layer being a polarizer sheet and the rest three
or more layers being non-polarizer sheets and interposing at least
the polarizer sheet which are mutually bonded with an adhesive or a
binder, and a resin layer, wherein one of the outermost layers of
the composite sheet B and the resin layer are integrated by the
thermal molding method, and at least one of the other sheet layers,
adhesive or binder layers, and the resin layer has the dimming
function. In this case, all the non-polarizer sheets of the
composite sheet may be formed of a resin of the same structure, or
sheets having different mechanical or optical performances may be
used as some of the sheets.
[0031] These transparent optical products usually have planar
structures at an adhering or binding stage for preparing the
composite sheet B, and are formed into curved structures having
spherical surfaces, curved surfaces or the like at an integration
stage with the resin layer or at an earlier stage, and further,
shaped into lenses together with the resin layer.
[0032] Description will be given to each layer in the layer
structure described above in relation to the transparent optical
product according to the invention and a method of preparing the
same.
[0033] It is preferable that the polarizer sheet to be used in the
invention is a uniaxially oriented resin sheet in consideration of
a bending property and a molding property. Usually, the polarizer
sheet is a uniaxially oriented sheet of polyvinyl alcohol,
polyvinyl formal, polyvinyl acetal, polyvinyl butylal, or the like
or denatured substances thereof, which usually has a uniform film
thickness of 1 mm or less.
[0034] While the polarizer sheet itself has a constant polarizing
performance, since a polarization degree of 80% or more is
practically desirable, iodine or a dichromatic dye is doped. The
polarizer sheet to be used for the invention can be prepared for
use by either of an iodine doping method and a dye doping
method.
[0035] In the iodine doping method using iodine, specific coloring
is less given to the polarizer sheet and a polarization degree is
higher as compared with the dye doping method using a dye. On the
contrary, there is a drawback that a thermal resistance is low.
[0036] On the other hand, the dye doping method provides a higher
thermal resistance. Where the polarizer sheet and other sheets are
bonded with an adhesive or a binder to prepare a composite sheet,
and further heated to prepare a polarizing optical product, or
where the composite sheet is provided in a thermoplastic resin or a
thermosetting resin or on a surface layer thereof to prepare a
polarizing optical product, higher workability can be obtained
since a processing temperature range can be further increased
during pressing or insert molding as compared with the polarizer
sheet prepared by the iodine doping method. On the other hand, the
dye doping method has a problem in that a hue peculiar to a dye
generally appears on the polarizer sheet. In particular, a light
transmittance rate in a greater wavelength than 650 nm is higher
than that in the other visible light wavelength region, that is, a
view through the polarizer sheet tends to look reddish.
[0037] For this reason, in the case in which the polarizer sheet
prepared by the dye doping method is to be used, it is preferred
that the hue peculiarly caused by coloring with a doping agent for
a polarizer is corrected and should be changed to be substantially
grayish. For this purpose, a pigment or a dye for correcting the
hue peculiar to the polarizer sheet may be blended in at least one
of the polarizer sheet layer, the other sheet layers, adhesive or
binder layers, and the resin layer which constitute the transparent
optical product according to the invention. The "substantially
grayish" implies a hue with which an object is viewed without color
change through the optical product.
[0038] Next, the non-polarizer sheet to be used in the invention
will be described. The non-polarizer sheet mainly serves to add a
practical function, for example, to protect the polarizer sheet, to
provide a strength or retention of shape of a transparent optical
product, or to provide an optical function such as a dimming
function. It is preferable that the non-polarizer sheet should be a
resin sheet having a high transparency, a great workability for
pressurizing and heating, and an excellent bonding property to the
polarizer sheet. While a thickness is not particularly restricted,
it is usually 10 mm or less. In consideration of the workability
and the productivity of the sheet itself, generally, the thickness
is approximately several .mu.m to 5 mm.
[0039] As the resin to be used for the non-polarizer sheet
according to the invention, examples of a thermoplastic resin
include a polycarbonate based resin, a polystyrene based resin, an
acryl based resin containing a monopolymer and a copolymer of such
as methylmethacrylate or a cyclohexylmethacrylate, a vinyl chloride
based resin, a polystyrene-methylmethacrylate based resin, an
acrylonitrile--styrene based resin, poly-4-methylpentene-1, a
principal chain hydrocarbon based resin having an adamantine ring
or a cyclopentane ring as a principal chain, a polyester based
resin having a fluorene group as a side chain, a polyamide based
resin such as clear nylon, a polyurethane based resin, an acyl
cellulose based cellulose resin such as acetyl cellulose or propyl
cellulose.
[0040] In particular, the thermoplastic resin to be used suitably
in the invention is the polycarbonate based resin because of a high
transparency, a high tenacity, a high thermal resistance and a high
refractive index. A typical polycarbonate based resin is
polybisphenol A carbonate. In addition, examples of the
polycarbonate based resin include homopolycarbonate such as
1,1'-dihydroxydiphenyl-phenylmethylmethane,
1,1'-dihydroxydiphenyl-diphenylmethane,
1,1'-dihydroxy-3,3'-dimethyldiphe- nyl-2,2-propane, their mutual
copolymer polycarbonate and copolymer polycarbonate with bisphenol
A.
[0041] In general, the polycarbonate based resin has a drawback
that a double refraction is increased easily. In other words, an
optical anisotropy is easily caused by a molding strain or a local
orientation in a molded body. For this reason, in the case in which
the polycarbonate based resin is to be used for the invention, it
is important that the formation of the optical anisotropy should be
prevented as much as possible. As a countermeasure, it is
preferable to use a resin which has a high fluidity, an
unsusceptibleness to excessive shearing force during molding, that
is, a residual strain or a local orientation are unlikely to occur,
and a relatively low polymerization degree. In the invention,
particularly, the use of a polycarbonate based resin having a
polymerization degree of 120 or less, more preferably, 100 or less
is recommended.
[0042] In order to prevent the optical anisotropy, moreover, a
resin having a modulus of photoelasticity of 30.times.10.sup.-3
cm.sup.2/dyne or less, preferably, 20.times.10.sup.-13
cm.sup.2/dyne or less and a glass transition temperature of
85.degree. C. or more, preferably, 90.degree. C. or more is
recommended in addition to the polycarbonate based resin in the
invention. If the modulus of photoelasticity is more than
30.times.10.sup.-11 cm.sup.2/dyne, the optical anisotropy is
remarkably caused by the residual strain or local orientation of
the sheet thus obtained. Moreover, if the glass transition
temperature is less than 85.degree. C., there is a problem in that
the practical property of the transparent optical product such as
sunglasses, goggles or corrective lenses is deteriorated, and
furthermore, deformation is easily caused in a higher order
processing requiring heating such as a hard coat or an
anti-reflection treatment.
[0043] As the thermoplastic resin to satisfy the modulus of
photoelasticity and the glass transition temperature, a
polymethylmethacrylate resin, a clear nylon resin, "Arton" produced
by JSR Co., Ltd. having an adamantine ring or a cyclopentane ring
as a principal chain, a resin having hydrocarbon as a principal
chain, for example, "Zeonex" produced by Nippon Zeon Co., Ltd. and
"Apel" produced by MITSUI CHEMICALS, INC., a polyester based resin
having a fluorene group as a side chain, for example, "Optoletz"
produced by Hitachi Chemical Co., Ltd., an acetyl cellulose resin
and a propyl cellulose resin are particularly recommended. These
resins are prepared in a sheet form by an extrusion molding method
or a cast molding method.
[0044] Since a composite sheet is usually processed or deformed
into a curved structure having a spherical surface, a curved
surface, or the like, it is preferable that the composite sheet has
a pressurizing or heating deformation property to some extent. It
is particularly preferable that the non-polarizer sheet is formed
of a thermoplastic resin. However, a thermosetting resin may be
used for the sheet, if the resin has a low degree of crosslinking
and a plastic deforming property so as to be processed into a
curved structure having a spherical surface or a curved
surface.
[0045] Examples of the thermosetting resin which can be used in the
invention include a polyfunctional allyl based resin such as
diethyleneglycolallyl carbonate (CR39) or diallylphthalate, a
polyfunctional acryl based resin, a polyfunctional polyurethane
based resin and a polyfunctional polythiourethane based resin, and
it is preferable that all of them have a crosslinking state
relieved by a copolymerization component.
[0046] Next, description will be given to a method of preparing the
composite sheet A or the composite sheet B according to the
invention. In any of the composite sheets, an adhesive or a binder
is used for bonding a polarizer sheet to other sheets. Both of the
adhesive and the binder are required to have durability for a long
period of time against water, heat, light and deformation, and are
not particularly restricted if they basically meet the
conditions.
[0047] Examples of the adhesive include an isocyanate based
adhesive, a polyurethane based adhesive, a polythiourethane based
adhesive, an epoxy based adhesive, a vinyl acetate based adhesive,
an acryl based adhesive and a wax based adhesive. Examples of the
binder include a vinyl acetate based binder and an acryl based
binder.
[0048] The adhesives and binders are uniformly applied onto a
polarizer sheet or other sheets by an ordinary applying method such
as a gravure coating method or an offset coating method. The
thickness of the adhesive or binder is usually 1 to 100 .mu.m.
[0049] In some cases, the surfaces of the polarizer sheet or other
sheets are subjected to a chemical solution treatment using acid or
alkali, an ultraviolet treatment, or a plasma or corona discharge
treatment in bonding or binding process in order to enhance bonding
to a base material.
[0050] Moreover, the composite sheet A or the composite sheet B can
be prepared by mutually superposing sheets to which an adhesive or
a binder is applied previously or immediately before sticking
directly from a roll or in a cutting state.
[0051] Next, the resin layer to be used in the invention will be
described. The resin layer mainly serves to give a practical
function such as protecting the composite sheet B or providing
strength, thermal resistance, figure retention or a lens power of
the transparent optical product.
[0052] A resin to be used for an outermost layer of the composite
sheet B and a resin to be used for a resin layer may be any resins
so far as they can be mutually integrated by a heat molding method,
and it is generally preferable that they are formed of resins of
the same structure. They may generally have a slight variation in a
copolymerization component, a polymerization degree, a viscosity
and an additive each other.
[0053] The heat molding method indicates a thermal molding method
such as a compression molding method, a transfer molding method or
an injection molding method, and an insert injection molding method
disclosed in Japanese Patent Application No. Hei 10-49707 is
basically preferable in respect of a productivity and precision in
the shape of a product. More specifically, the composite sheet B is
set in a metal mold so that the outermost layer thereof, which can
be mutually integrated with the resin of the resin layer, is faced
to the molding chamber side in the mold, and then the resin is
injected to mold the resin layer.
[0054] In particular, an injection compression molding method of an
insert type is preferable for the use in which the precision in a
shape is particularly required, for example, sunglasses, goggles or
corrective lenses. Since a resin is injected into a metal mold at a
low pressure and the metal mold is then closed at a high pressure
to apply compression force to the resin in the injection
compression molding method, an optical anisotropy due to the
molding strain of a molded body or a local orientation during
molding is unlikely to be caused. By controlling metal mold
compression force to be uniformly applied to the resin, moreover,
the resin can be cooled at a constant specific volume.
Consequently, a molded product having high dimensional precision
can be obtained. In particular, this method can be preferably
applied to a polycarbonate based resin having a high double
refraction.
[0055] The resin layer is heated and molded to have a uniform
thickness on the composite sheet B, that is, to form a plano lens
or a semifinished lens, or to form a lens having minus or plus
power.
[0056] If the thickness of the composite sheet B of the invention
is represented by x and the thickness of the resin layer is
represented by y, x is usually approximately 0.1 mm to 2 mm in all
regions of the transparent optical product according to the
invention so that the composite sheet can have a uniform thickness.
On the other hand, y may have a uniform thickness or the thickness
continuously varied from a central part toward the periphery as in
a case of a minus power lens or a plus power lens. Referring to a
range within a 35 mm radius from the center of the transparent
optical product, y can usually be set to approximately 0.5 mm to 20
mm in any place according to the invention.
[0057] It is preferable that x and y have a relationship of
100.gtoreq.y/x.gtoreq.0.3, particularly, 80.gtoreq.y/x.gtoreq.0.5
in every part of the transparent optical product according to the
invention. If y/x is more than 100, y is increased too much so that
the weight of the transparent optical product increases or the
precise molding property of the resin layer is deteriorated in some
cases. Alternatively, when x is reduced too much, the composite
sheet B is improperly prepared in some cases. Moreover, if y/x is
less than 0.3, x is increased too much so that preparation of the
composite sheet B is difficult or a workability thereof is
deteriorated.
[0058] Next, description will be given to a dimming function which
at least one layer other than the polarizer sheet according to the
invention provides. The dimming function is given by using a
dimming dye.
[0059] The type of the dimming dye to be used in the invention is
not particularly restricted but may include a spiropyrane based
dye, a naphthopyrane based dye, a furan based dye, a spiro oxazine
based dye, a fulgide based dye and a chromene based dye which are
generally used. It is preferable that the dimming dye has a high
coloring concentration against ultraviolet rays, a high coloring
speed, a hue which is as colorless as possible after the removal of
the ultraviolet rays, a high achromatic speed, and an excellent
durability for short and long periods of time under processing
conditions, practical conditions and storage conditions such as
heat, light or humidity. As a hue obtained after coloring, brown
and gray are generally desirable. Therefore, plural kinds of
dimming dyes are usually used at the same time and the ratio and
amount of each dye to be used are determined to obtain a favorite
hue.
[0060] In order to form a transparent optical product in which at
least one layer of other than the polarizer sheet has the dimming
function, in the invention, a dimming dye is blended into at least
one of the non-polarizer sheets constituting a transparent optical
product, adhesive or binder layers for bonding the sheets to the
polarizer sheet to prepare a composite sheet, and a resin layer by
means of an adding method such as a kneading method or an
after-processing method such as a dyeing method or a coating
method. In the case in which plural kinds of dimming dyes are used
at the same time it is generally easier and more economical to
blend all the dimming dyes into one layer rather than blending each
dye to each layer separately by a preadding method.
[0061] In respect of the easiness of control of the blending
amount, generally, the kneading method is often employed. However,
since the dimming dye is blended to the non-polarizer sheets or the
resin sheet as a pellet or during molding, the dimming dye receives
the fusing thermal history of a resin and is therefore degraded
thermally in some cases. Moreover, in the case that the thickness y
of the resin layer is not uniform, the depth of the hue differs
depending on the thickness of the layer, blending of the dimming
dye into the resin layer should be carried out carefully.
[0062] Also in the kneading method, in the case in which the
dimming dye is particularly kneaded into an adhesive or a binder,
the blending can be carried out at a low temperature of 100.degree.
C. or less and the dimming dye can be prevented from being
thermally degraded. Therefore, the kneading method is
excellent.
[0063] Moreover, a method of chemically or physically dyeing, in
which the dimming dye is impregnated or diffused from at least one
of surfaces of the transparent optical product to the inside
thereof, can also provide the dimming function at a relatively low
temperature and can be preferably used for convenience.
[0064] Furthermore, a coating method of applying a hard coat or a
primer coat containing a dimming dye in a thickness of
approximately 1 to 100 .mu.m onto at least one of the surfaces of
the transparent optical product to provide a film having the
dimming function is also convenient and can be preferably used.
[0065] It is possible to give the dimming dye a polymerization
group such as a (metha)acryloiloxy group or a (metha)allyl group.
If a copolymerization component having a bonding function or a
binding function is used, it can be utilized as an adhesive or a
binder having a dimming performance in the invention. Moreover, if
a copolymerization component having a function of increasing an
adhesion to a base material and a film hardness is used, it is
possible to provide at least one of the surfaces of the transparent
optical product with a film having the dimming performance by the
coating method.
[0066] Referring to the structures and arrangements of the
composite sheet and the resin layer which constitute the
transparent optical product according to the invention, a portion
in which a dimming dye is to be blended and a blending method,
preferred embodiments according to the invention will be
illustrated as follows. (/) indicates a portion in which bonding is
carried out through an adhesive layer or a binder layer, =indicates
a portion in which the non-polarizer sheets and the resin layer are
to be integrated by the heat molding method, a mark * indicates a
portion in which the dimming dye is to be blended by the kneading
method, a mark ** indicates a portion in which the dimming dye is
to be given and blended to the inside of the surface by the dyeing,
impregnating or diffusing method, and a mark *** indicates a
portion in which the dimming dye is to be given and blended to the
surface through a film in the coating method.
[0067] (1) other sheet (/) polarizer sheet (1*) other sheet
[0068] (2) other sheet (/) polarizer sheet (/) other sheet *
[0069] (3) other sheet (/) polarizer sheet (/) other sheet **
[0070] (4) other sheet (/) polarizer sheet (/) other sheet ***
[0071] (5) other sheet (/) polarizer sheet (/*) other sheet=resin
layer
[0072] (6) other sheet (1)polarizer sheet (/)other sheet=resin
layer
[0073] (7) other sheet *(/)polarizer sheet (/)other sheet=resin
layer
[0074] (8) other sheet *(/)polarizer sheet (/) other sheet=resin
layer
[0075] (9) other sheet ***(/) polarizer sheet (/) other sheet=resin
layer
[0076] (10) other sheet (/)polarizer sheet (/)other sheet*=resin
layer
[0077] (11) other sheet (/)polarizer sheet (/)other sheet=resin
layer *
[0078] (12) other sheet (/) polarizer sheet (/) other sheet=resin
layer
[0079] (13) other sheet (/) polarizer sheet (/) other sheet=resin
layer ***
[0080] The invention includes the case in which the "other sheet"
is one layer sheet and the case in which the "other sheet" is a
composite-sheet including a plurality of resin sheets having the
same structure which are mutually bonded with an adhesive or a
binder or is a composite sheet including a plurality of resin
sheets having different structure.
[0081] It is preferable that the transparent optical product
according to the invention has a surface on at least one of sides
which is subjected to a hard coat processing. Examples of the hard
coat include a thermosetting type hard coat such as a silane based
hard coat or an epoxy based hard coat and an active ray curing type
hard coat such as an acryl based hard coat or an epoxy based hard
coat which are generally used. Usually, the hard coat is given in a
film thickness of approximately 0.5 to 15 .mu.m.
[0082] Moreover, it is preferable that the polarizing optical
product according to the invention has a surface on at least one of
sides which is subjected to an antireflection processing. In the
antireflection processing, usually, approximately two to eight
inorganic films having different refractive indices from each other
are laminated by vacuum evaporation or approximately one to three
organic films are laminated by a wet method in an optical thickness
adjacently over the hard coat.
[0083] Furthermore, it is preferable that the polarizing optical
product according to the invention has a surface on at least one of
sides which is subjected to an antifouling processing. In the
antifouling processing, a fluorine based organic compound is
usually given in a thickness of several tens nm to order of .mu.m
by the vacuum evaporation or the wet method in order to prevent
contamination from being caused by an organic substance, for
example, the contamination of an antireflection film by
fingerprints and to easily wipe up the contamination.
[0084] Moreover, it is preferable that the polarizing optical
product according to the invention has a surface on at least one of
sides which is subjected to an antifogging processing. In the
antifogging processing, a hydrophilic resin such as a polyvinyl
alcohol based resin or a polyvinyl pyrrolidone based resin is
usually given in a thickness of approximately 1 to 50 .mu.m.
[0085] Next, the invention will be specifically described by taking
examples but is not restricted thereto.
EXAMPLE 1
[0086] One of surfaces of a polyvinyl alcohol based polarizer sheet
having a thickness of approximately 20 .mu.m was coated with a
binder ("Saibinol" AT-245 produced by Saiden Chemical Co., Ltd.)
containing 10% by weight of a spiro oxazine based dimming dye
1,3,3,5,6-pentamethylspiro-
[indolino-2,3'[3H]naphto(2,1b)(1,4)oxazine based on a solid content
in a thickness of 30 .mu.m.
[0087] A polycarbonate sheet having a thickness of 400 .mu.m
prepared by using a polycarbonate resin having a mean
polymerization degree of approximately 80 was stuck onto the binder
surface.
[0088] In the same manner as described above, furthermore, the
other surface of the polarizer sheet was coated with a binder which
does not contain the dimming dye and the polycarbonate sheet was
stuck onto the same portion. A composite sheet thus obtained was
subjected to a bonding processing at 40.degree. C. so that a
polarizing and dimming transparent optical product having a
thickness of 0.88 mm and a visible light transmittance of 50% was
obtained.
[0089] The transparent optical product was exposed to the direct
rays of the sun to cause a color of the dimming dye to come out and
a visible light transmittance measured immediately was 20%. When
the color of the transparent optical product was caused to
disappear under room light, the visible light transmittance was
returned to an almost original state.
[0090] Moreover, when the transparent optical product and the
polarizer sheet were set into crossed Nicols, a remarkable
photoelastic phenomenon was not observed with the polarizer sheet
put on either side of the transparent optical product.
EXAMPLE 2
[0091] One of surfaces of a polyvinyl alcohol based polarizer sheet
having a thickness of 20 .mu.m was coated with a binder ("Saibinol"
AT-245 produced by Saiden Chemical Co., Ltd.) containing 10% by
weight of a Spiro oxazine based dimming dye
1,3,3,5,6-pentamethylspiro[indolino-2,3'[- 3H]naphto(2,1b)(1,4)
oxazine based on a solid content in a thickness of 30 .mu.m.
[0092] A TAC sheet composite sheet having a thickness of 400 .mu.m
prepared by bonding two triacetate (TAC) sheets having a thickness
of 190 .mu.m was stuck onto the binder surface.
[0093] In the same manner as described above, furthermore, the
other surface of the polarizer sheet was coated with a binder which
does not contain the dimming dye and the TAC sheet composite sheet
was stuck onto the same portion. A composite sheet thus obtained
was subjected to a bonding processing at 40.degree. C. so that a
polarizing and dimming transparent optical product having a
thickness of 0.88 mm and a visible light transmittance of 52% was
obtained.
[0094] The transparent optical product was exposed to the direct
rays of the sun to cause a color of the dimming dye to come out and
a visible light transmittance measured immediately was 23%. When
the color of the transparent optical product was caused to
disappear under room light, the visible light transmittance was
returned to an almost original state.
[0095] Moreover, when the transparent optical product and the
polarizer sheet were set into crossed Nicols, a remarkable
photoelastic phenomenon was not observed with the polarizer sheet
put on either side of the transparent optical product.
EXAMPLE 3
[0096] One of surfaces of a polycarbonate sheet having a thickness
of 400 .mu.m prepared by blending 1% by weight of the dimming dye
utilized in the example 1 into a polycarbonate resin having a mean
polymerization degree of approximately 80 was coated with a binder
("Saibinol" AT-245 produced by Saiden Chemical Co., Ltd.) in a
thickness of 30 .mu.m. Thus, a dimming dye blended polycarbonate
sheet having the binder was prepared.
[0097] Furthermore, a polycarbonate sheet having a binder was
prepared in the same manner as described above except that the
dimming dye was not blended.
[0098] The dimming dye blended polycarbonate sheet having the
binder was stuck to one of the surfaces of a polyvinyl alcohol
based polarizer sheet having a thickness of 20 .mu.m and the
polycarbonate sheet having the binder was stuck to the other
surface, and a bonding processing was carried out. A composite
sheet thus obtained was a polarizing and dimming transparent
optical product having a thickness of 0.88 mm and a visible light
transmittance of 41%.
[0099] The transparent optical product was exposed to the direct
rays of the sun to cause a color of the dimming dye to come out and
a visible light transmittance measured immediately was 12%. When
the color of the transparent optical product was caused to
disappear under room light, the visible light transmittance was
returned to an almost original state.
[0100] Moreover, when the transparent optical product and the
polarizer sheet were set into crossed Nicols, a remarkable
photoelastic phenomenon was not observed with the polarizer sheet
put on either side of the transparent optical product.
EXAMPLE 4
[0101] One of surfaces of a sheet having a thickness of 1 mm
prepared by using a resin "Arton G" produced by JSR Co., Ltd. in
which a modulus of photoelasticity measured by an ellipsometer
method is 4.1.times.10.sup.-13 cm.sup.2/dyne and a glass transition
temperature is 170.degree. C. was coated, in a thickness of 30
.mu.m, with a binder ("Saibinol" AT-D40 produced by Saiden Chemical
Co., Ltd.) containing 10% by weight of the spiro oxazine based
dimming dye used in the example 1 based on a solid content. Thus, a
dimming dye blended sheet having the binder was prepared.
[0102] In the same manner as described above, an "Arton G" resin
sheet having a thickness of 1 mm which does not include the dimming
dye but has a binder was prepared.
[0103] The "Arton G" resin sheet containing the dimming dye and
having the binder was stuck to one of surfaces of a polyvinyl
alcohol based polarizer sheet having a thickness of 20 .mu.m and
the "Arton G" resin sheet containing no dimming dye and having the
binder was stuck to the other surface, and they were subjected to a
bonding processing. A composite sheet thus obtained was a
polarizing and dimming transparent optical product having a
thickness of 2.08 mm and a visible light transmittance of 53%.
[0104] The transparent optical product was exposed to the direct
rays of the sun to cause a color of the dimming dye to come out and
a visible light transmittance measured immediately was 23%. When
the color of the transparent optical product was caused to
disappear under room light, the visible light transmittance was
returned to an almost original state (54%).
[0105] Moreover, when the transparent optical product and the
polarizer sheet were set into crossed Nicols, a remarkable
photoelastic phenomenon was not observed with the polarizer sheet
put on either side of the transparent optical product.
EXAMPLE 5
[0106] In order to carry out insert molding, the composite sheet
prepared in the example 1 was molded into a convex spherical shape
equally to the curvature of a concave metal mold. In that case, a
polycarbonate sheet containing a dimming dye and having a binder
was set to the front surface of a convex body (the convex side of a
spherical molded body).
[0107] The convex side of the molded body thus obtained was set to
the concave metal mold and was sucked onto the molding surface of
the concave metal mold through a sucking hole provided on the
concave metal mold, thereby forming a molding cavity together with
a convex metal mold.
[0108] By using a polycarbonate resin having a polymerization
degree of approximately 80 as a resin layer, a lens-shaped
polarizing and dimming transparent optical product was subjected to
the insert molding by an injection compression molding method. The
transparent optical product thus obtained is a plano lens in which
a composite sheet having a polarizing and dimming function in a
thickness (x) of 0.88 mm is provided on the front surface of the
lens and a resin layer integrated therewith and having a radius of
35 mm and a thickness (y) of 2 mm is provided in a rear part.
[0109] The transparent optical product was exposed to the direct
rays of the sun to cause a color of the dimming dye to come out and
a visible light transmittance immediately measured in the central
part of the lens was 19%. When the color of the transparent optical
product was caused to disappear under room light, the visible light
transmittance was returned to an almost original state (48%).
[0110] Moreover, when the lens and the polarizer sheet were set
into crossed Nicols, a remarkable photoelastic phenomenon was not
observed with the polarizer sheet put on either side of the
lens.
EXAMPLE 6
[0111] The composite sheet prepared in the example 4 was molded
into a convex spherical shape in which an "Arton G" resin sheet
containing a dimming dye and having a binder is provided on a front
surface (the convex side of a spherical molded body) equally to the
curvature of a concave metal mold. The convex side of the molded
body thus obtained was set to the concave metal mold and was sucked
onto the molding surface of the concave metal mold through a
sucking hole provided on the concave metal mold, thereby forming a
molding cavity together with a convex metal mold.
[0112] By using the "Arton G" resin as a resin layer, a lens-shaped
polarizing and dimming transparent optical product was subjected to
insert molding by an injection compression molding method.
[0113] The transparent optical product thus obtained is a
semifinished lens in which a composite sheet including a polarizer
sheet and having a thickness (x) of 2.08 mm is provided on the
front surface of the lens and a resin layer integrated therewith
and having a radius of 35 mm and a thickness of approximately 13 mm
is provided in a rear part.
[0114] The rear side of the lens was polished to fabricate a lens
having a minus power in which a center has a thickness of 3 mm (the
resin layer has a thickness y of 0.92 mm) and the peripheral part
of the lens has a thickness of 5 mm (the resin layer has a
thickness y of 2.92 mm).
[0115] The transparent optical product was exposed to the direct
rays of the sun to cause a color of the dimming dye to come out and
a visible light transmittance immediately measured in the central
part of the lens was 22%. When the color of the transparent optical
product was caused to disappear under room light, the visible light
transmittance was returned to an almost original state (53%).
[0116] Moreover, when the lens and the polarizer sheet were set
into crossed Nicols, a remarkable photoelastic phenomenon was not
observed with the polarizer sheet put on either side of the
lens.
COMPARATIVE EXAMPLE 1
[0117] A polarizing and dimming transparent optical product was
prepared in the same manner as in the example 1 except that a
polycarbonate resin had a mean polymerization degree of
approximately 120.
[0118] When the transparent optical product and the polarizer sheet
were set into crossed Nicols, a remarkable photoelastic phenomenon
was observed with the polarizer sheet put on either side of the
transparent optical product.
[0119] According to the invention, it is possible to provide an
inexpensive polarizing and dimming transparent optical product
having a polarizing function and a dimming function, for example,
polarizing and dimming sunglasses, goggles and lenses.
[0120] [Industrial Applicability]
[0121] The invention is useful for a transparent optical product,
particularly, a chair form transparent optical product such as
sunglasses, goggles or lenses.
* * * * *