U.S. patent application number 14/930805 was filed with the patent office on 2016-06-09 for optical component and timepiece.
The applicant listed for this patent is SEIKO EPSON CORPORATION. Invention is credited to Daiki FURUSATO, Katsumi SUZUKI.
Application Number | 20160161641 14/930805 |
Document ID | / |
Family ID | 55969659 |
Filed Date | 2016-06-09 |
United States Patent
Application |
20160161641 |
Kind Code |
A1 |
FURUSATO; Daiki ; et
al. |
June 9, 2016 |
OPTICAL COMPONENT AND TIMEPIECE
Abstract
An optical component includes a base material and an
antireflection film containing silica particles, wherein the silica
particles have a first local maximum in the range of 1.5 nm or more
and 2.5 nm or less (a first range), a second local maximum in the
range of 3.5 nm or more and 4.5 nm or less (a second range), and a
third local maximum in the range of 7.5 nm or more and 8.5 nm or
less (a third range) in a number-based particle size distribution.
It is preferred that the silica particles have a fourth local
maximum in the range of 5.5 nm or more and 6.5 nm or less in the
number-based particle size distribution.
Inventors: |
FURUSATO; Daiki; (Ina,
JP) ; SUZUKI; Katsumi; (Chino, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEIKO EPSON CORPORATION |
Tokyo |
|
JP |
|
|
Family ID: |
55969659 |
Appl. No.: |
14/930805 |
Filed: |
November 3, 2015 |
Current U.S.
Class: |
368/296 ;
359/580; 977/773 |
Current CPC
Class: |
Y10S 977/773 20130101;
G04B 39/006 20130101; G04B 39/002 20130101; G02B 1/113 20130101;
G02B 1/118 20130101; G02B 2207/107 20130101; B82Y 30/00
20130101 |
International
Class: |
G02B 1/118 20060101
G02B001/118; G04B 39/00 20060101 G04B039/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 3, 2014 |
JP |
2014-244845 |
Claims
1. An optical component comprising: a base material; and an
antireflection film containing silica particles, wherein the silica
particles have a first local maximum in the range of 1.5 nm or more
and 2.5 nm or less, a second local maximum in the range of 3.5 nm
or more and 4.5 nm or less, and a third local maximum in the range
of 7.5 nm or more and 8.5 nm or less in a number-based particle
size distribution.
2. The optical component according to claim 1, wherein the ratio of
the silica particles having a particle diameter of 1.5 nm or more
and 2.5 nm or less to the sum of the volumes of the silica
particles constituting the antireflection film is 5% by volume or
more and 30% by volume or less.
3. The optical component according to claim 1, wherein the ratio of
the silica particles having a particle diameter of 3.5 nm or more
and 4.5 nm or less to the sum of the volumes of the silica
particles constituting the antireflection film is 10% by volume or
more and 40% by volume or less.
4. The optical component according to claim 1, wherein the ratio of
the silica particles having a particle diameter of 7.5 nm or more
and 8.5 nm or less to the sum of the volumes of the silica
particles constituting the antireflection film is 30% by volume or
more and 60% by volume or less.
5. The optical component according to claim 1, wherein the silica
particles have a fourth local maximum in the range of 5.5 nm or
more and 6.5 nm or less in the number-based particle size
distribution.
6. The optical component according to claim 1, wherein the ratio of
the silica particles having a particle diameter of 5.5 nm or more
and 6.5 nm or less to the sum of the volumes of the silica
particles constituting the antireflection film is 20% by volume or
more and 30% by volume or less.
7. The optical component according to claim 1, wherein the
thickness of the antireflection film is 50 nm or more and 120 nm or
less.
8. The optical component according to claim 1, wherein the base
material is composed of a material containing at least one member
selected from the group consisting of a silicate glass, a sapphire
glass, and a plastic.
9. The optical component according to claim 1, wherein the optical
component is a cover glass for a timepiece.
10. A timepiece comprising the optical component according to claim
1.
11. A timepiece comprising the optical component according to claim
2.
12. A timepiece comprising the optical component according to claim
3.
13. A timepiece comprising the optical component according to claim
4.
14. A timepiece comprising the optical component according to claim
5.
15. A timepiece comprising the optical component according to claim
6.
16. A timepiece comprising the optical component according to claim
7.
17. A timepiece comprising the optical component according to claim
8.
18. A timepiece comprising the optical component according to claim
9.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present invention relates to an optical component and a
timepiece.
[0003] 2. Related Art
[0004] In an optical component such as a cover glass for a
timepiece, an antireflection film which prevents light reflection
is provided for the purpose of enhancing visibility on an opposite
surface side or the like.
[0005] In the related art, an optical component had a complicated
structure such that many layers are stacked on one another for
obtaining a sufficient antireflection function (see, for example
JP-A-2010-37115). Further, in the related art, each layer
constituting an antireflection film is formed by a chemical vapor
deposition and therefore, the productivity of the optical component
is poor, and also the production cost is high.
SUMMARY
[0006] An advantage of some aspects of the invention is to provide
an optical component including an antireflection film having an
excellent antireflection function with a simple structure, and also
to provide a timepiece including the optical component.
[0007] An optical component according to an aspect of the invention
includes a base material and an antireflection film containing
silica particles, wherein the silica particles have a first local
maximum in the range of 1.5 nm or more and 2.5 nm or less, a second
local maximum in the range of 3.5 nm or more and 4.5 nm or less,
and a third local maximum in the range of 7.5 nm or more and 8.5 nm
or less in a number-based particle size distribution.
[0008] According to this configuration, an optical component
including an antireflection film having an excellent antireflection
function with a simple structure can be provided.
[0009] In the optical component according to the aspect of the
invention, it is preferred that the ratio of the silica particles
having a particle diameter of 1.5 nm or more and 2.5 nm or less to
the sum of the volumes of the silica particles constituting the
antireflection film is 5% by volume or more and 30% by volume or
less.
[0010] According to this configuration, the antireflection film can
be made relatively dense while making the antireflection function
of the antireflection film particularly excellent, and the strength
of the antireflection film and the durability of the optical
component can be made particularly excellent.
[0011] In the optical component according to the aspect of the
invention, it is preferred that the ratio of the silica particles
having a particle diameter of 3.5 nm or more and 4.5 nm or less to
the sum of the volumes of the silica particles constituting the
antireflection film is 10% by volume or more and 40% by volume or
less.
[0012] According to this configuration, the antireflection film can
be made relatively dense while making the antireflection function
of the antireflection film particularly excellent, and the strength
of the antireflection film and the durability of the optical
component can be made particularly excellent.
[0013] In the optical component according to the aspect of the
invention, it is preferred that the ratio of the silica particles
having a particle diameter of 7.5 nm or more and 8.5 nm or less to
the sum of the volumes of the silica particles constituting the
antireflection film is 30% by volume or more and 60% by volume or
less.
[0014] According to this configuration, the antireflection film can
be made relatively dense while making the antireflection function
of the antireflection film particularly excellent, and the strength
of the antireflection film and the durability of the optical
component can be made particularly excellent.
[0015] In the optical component according to the aspect of the
invention, it is preferred that the silica particles have a fourth
local maximum in the range of 5.5 nm or more and 6.5 nm or less in
the number-based particle size distribution.
[0016] According to this configuration, the antireflection function
of the antireflection film can be made particularly excellent.
[0017] In the optical component according to the aspect of the
invention, it is preferred that the ratio of the silica particles
having a particle diameter of 5.5 nm or more and 6.5 nm or less to
the sum of the volumes of the silica particles constituting the
antireflection film is 20% by volume or more and 30% by volume or
less.
[0018] According to this configuration, the antireflection film can
be made relatively dense while making the antireflection function
of the antireflection film particularly excellent, and the strength
of the antireflection film and the durability of the optical
component can be made particularly excellent.
[0019] In the optical component according to the aspect of the
invention, it is preferred that the thickness of the antireflection
film is 50 nm or more and 120 nm or less.
[0020] According to this configuration, the durability,
antireflection function, and the like of the optical component can
be made particularly excellent.
[0021] In the optical component according to the aspect of the
invention, it is preferred that the base material is composed of a
material containing at least one member selected from the group
consisting of a silicate glass, a sapphire glass, and a
plastic.
[0022] These materials have excellent transparency, and therefore,
the optical property of the optical component can be made
particularly excellent. Further, in the case where an
antireflection film is provided on a base material composed of such
a material, the antireflection function attributed to the
antireflection film is more effectively exhibited.
[0023] In the optical component according to the aspect of the
invention, it is preferred that the optical component is a cover
glass for a timepiece.
[0024] The cover glass is present at a place close to the viewpoint
of an observer (a user or the like) at the time of using a
timepiece, and also time-displaying members such as a dial plate
and hands are generally disposed on a rear surface side of the
cover glass, and therefore, the cover glass (optical component) is
a member which is strongly required to have visibility of a dial
plate and the like through the cover glass (optical component).
Therefore, in the case where the aspect of the invention with which
a high antireflection function is exhibited is applied to a cover
glass, the effect of the aspect of the invention is more remarkably
exhibited.
[0025] Further, the cover glass is a component which has many
opportunities to be visually recognized by an observer (a user or
the like), and has a large influence on the appearance of the
entire timepiece. In the aspect of the invention, a high
antireflection function is exhibited, and therefore, the excellent
appearance (aestheticity) inherent in an ornamental component such
as a dial plate which is visually recognized through the cover
glass can be effectively exhibited. Therefore, by applying the
aspect of the invention to a cover glass for a timepiece, the
aesthetic appearance of the timepiece as a whole can be made
particularly excellent.
[0026] A timepiece according to an aspect of the invention includes
the optical component according to the aspect of the invention.
[0027] According to this configuration, a timepiece capable of
favorably visually recognizing a state on a rear surface side of
the optical component can be provided, and the aesthetic appearance
(aestheticity) of the timepiece as a whole can be made excellent,
and thus, the value as an ornament can be increased. Further, for
example, the visibility of the time and the like can be improved,
and thus, also the function (practicality) as a utility article
becomes excellent.
[0028] According to the aspects of the invention, an optical
component including an antireflection film having a sufficient
antireflection function with a simple structure can be provided,
and also a timepiece including the optical component can be
provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The invention will be described with reference to the
accompanying drawings, wherein like numbers reference like
elements.
[0030] FIG. 1 is a cross-sectional view schematically showing a
first embodiment of an optical component according to the
invention.
[0031] FIG. 2 is a view schematically showing one example of a
particle size distribution of silica particles constituting an
antireflection film of an optical component according to the
invention.
[0032] FIG. 3 is a cross-sectional view schematically showing a
second embodiment of an optical component according to the
invention.
[0033] FIG. 4 is a partial cross-sectional view showing a preferred
embodiment of a timepiece (wristwatch) according to the
invention.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0034] Hereinafter, preferred embodiments of the invention will be
described in detail with reference to the accompanying
drawings.
Optical Component
[0035] First, an optical component according to the invention will
be described.
First Embodiment
[0036] FIG. 1 is a cross-sectional view schematically showing a
first embodiment of an optical component according to the
invention, and FIG. 2 is a view schematically showing one example
of a particle size distribution of silica particles constituting an
antireflection film of an optical component according to the
invention.
[0037] As shown in FIG. 1, an optical component P10 of this
embodiment includes a base material P1 and an antireflection film
P2 containing silica particles P21.
[0038] The silica particles P21 contained in the antireflection
film P2 have a given particle size distribution.
[0039] That is, the silica particles P21 contained in the
antireflection film P2 have a first local maximum MV1 in the range
of 1.5 nm or more and 2.5 nm or less (a first range R1), a second
local maximum MV2 in the range of 3.5 nm or more and 4.5 nm or less
(a second range R2), and a third local maximum MV3 in the range of
7.5 nm or more and 8.5 nm or less (a third range R3) in a
number-based particle size distribution (see FIG. 2).
[0040] Because of having such a particle size distribution, an
excellent antireflection function is obtained. In particular, with
a very simple structure as compared with an antireflection film in
the related art, an excellent antireflection function is
obtained.
[0041] The reason why such an excellent antireflection function is
obtained is considered to be because by including the silica
particles P21 having a particle size distribution as described
above, the refractive index is decreased as compared with silica in
a bulk form, and thus, a favorable optical interference effect is
exhibited.
[0042] Further, by including the silica particles P21 having a
particle size distribution as described above, the optical
component P10 has an excellent antifogging property. As a result, a
decrease in the optical property due to dew condensation or the
like can be reliably prevented.
[0043] The reason why such an excellent antifogging property is
obtained is considered to be because by including the silica
particles P21 having a particle size distribution as described
above, a fine fractal structure is favorably formed.
[0044] Further, in the related art, an antireflection function is
sometimes exhibited by providing a resin film which can be formed
easily, however, such a resin film has a problem that not only the
antireflection function is low but also the abrasion resistance is
low, and for example, when dirt adheres to the surface of the
optical component, a wiping operation cannot be performed, and the
like. On the other hand, the antireflection film P2 as described
above has also excellent abrasion resistance, and therefore, a
wiping operation can also be favorably performed.
[0045] Such an antireflection film P2 can be more easily formed by,
for example, a coating method or the like as described in detail
later.
[0046] Due to this, the optical component P10 having an excellent
antireflection function and the like can be obtained with high
productivity without using a large and expensive apparatus.
Further, the production cost of the optical component P10 can also
be decreased.
[0047] Further, the density (the filling ratio of the silica
particles P21) of the antireflection film P2 can be made high, and
thus, the strength of the antireflection film P2 and the durability
of the optical component P10 can be made excellent.
Base Material
[0048] The base material P1 constitutes a main part of the optical
component P10 and is generally a member which has light
transmittance.
[0049] The refractive index of the base material P1 for a light
with a wavelength of 589 nm is preferably 1.43 or more and 1.85 or
less, more preferably 1.45 or more and 1.78 or less.
[0050] According to this, the optical property of the optical
component P10 can be made particularly excellent.
[0051] The constituent material of the base material P1 is not
particularly limited, and for example, various glasses, various
plastics, and the like can be used. However, it is preferably a
material containing at least one member selected from the group
consisting of a silicate glass (a quartz glass or the like), a
sapphire glass, and a plastic.
[0052] These materials have excellent transparency. Further, in the
case where the antireflection film P2 is provided on the base
material P1 composed of such a material, the antireflection
function attributed to the antireflection film P2 is more
effectively exhibited.
[0053] In particular, in the case where the base material P1
contains at least one of a silicate glass and a sapphire glass,
excellent optical properties such as particularly excellent light
transmittance and a moderate refractive index are obtained, and
also the adhesiveness thereof to the antireflection film P2 is made
particularly excellent, and thus, the durability of the optical
component P10 as a whole can be made particularly excellent.
[0054] Examples of a plastic material constituting the base
material P1 include various thermoplastic resins and various
thermosetting resins, and specific examples thereof include
polyolefins such as polyethylene, polypropylene, ethylene-propylene
copolymers, and ethylene-vinyl acetate copolymers (EVA), cyclic
polyolefins (COP), modified polyolefins, polyvinyl chloride,
polyvinylidene chloride, polystyrene, polyamides (for example,
nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 11, nylon
12, nylon 6-12, and nylon 6-66), polyimides, polyamideimides,
polycarbonate (PC), poly-(4-methylpentene-1), ionomers, acrylic
resins, polymethyl methacrylate, acrylonitrile-butadiene-styrene
copolymers (ABS resins), acrylonitrile-styrene copolymers (AS
resins), butadiene-styrene copolymers, polyoxymethylene, polyvinyl
alcohol (PVA), ethylene-vinyl alcohol copolymers (EVOH), polyesters
such as polyethylene terephthalate (PET), polybutylene
terephthalate (PET), and polycyclohexane terephthalate (PCT),
polyether, polyether ketone (PEK), polyether ether ketone (PEEK),
polyether imide, polyacetal (POW, polyphenylene oxide, modified
polyphenylene oxide, polysulfone, polyether sulfone, polyphenylene
sulfide, polyarylate, aromatic polyesters (liquid crystal
polymers), polytetrafluoroethylene, polyvinylidene fluoride, other
fluororesins, various thermoplastic elastomers such as
styrene-based, polyolefin-based, polyvinyl chloride-based,
polyurethane-based, polyester-based, polyamide-based,
polybutadiene-based, trans-polyisoprene-based, fluororubber-based,
and chlorinated polyethylene-based elastomers, epoxy resins,
phenolic resins, urea resins, melamine resins, unsaturated
polyesters, silicone-based resins, urethane-based resins,
poly-para-xylylene resins such as poly-para-xylylene,
poly-monochloro-para-xylylene, poly-dichloro-para-xylylene,
poly-monofluoro-para-xylylene, and poly-monoethyl-para-xylylene,
and also include copolymers, blends, and polymer alloys composed
mainly of these materials. Among these, one type or two or more
types in combination (for example, as a blend resin, a polymer
alloy, a stacked body, or the like) can be used.
Antireflection Film
[0055] The antireflection film P2 is composed of a material
containing a plurality of silica particles P21 having a given
particle size distribution.
[0056] That is, the silica particles P21 have a first local maximum
Mill in the range of 1.5 nm or more and 2.5 nm or less (a first
range R1), a second local maximum MV2 in the range of 3.5 nm or
more and 4.5 nm or less (a second range R2), and a third local
maximum MV3 in the range of 7.5 nm or more and 8.5 nm or less (a
third range R3) in a number-based particle size distribution.
[0057] The ratio of the silica particles P21 having a particle
diameter of 1.5 nm or more and 2.5 nm or less (the ratio of the
silica particles P21 falling within the first range R1) to the sum
of the volumes of the silica particles P21 constituting the
antireflection film P2 is preferably 5% by volume or more and 30%
by volume or less, more preferably 10% by volume or more and 25% by
volume or less.
[0058] According to this, the antireflection film P2 can be made
relatively dense while making the antireflection function of the
antireflection film P2 particularly excellent, and the strength of
the antireflection film P2 and the durability of the optical
component P10 can be made particularly excellent.
[0059] The ratio of the silica particles P21 having a particle
diameter of 3.5 nm or more and 4.5 nm or less (the ratio of the
silica particles P21 falling within the second range R2) to the sum
of the volumes of the silica particles P21 constituting the
antireflection film P2 is preferably 10% by volume or more and 40%
by volume or less, more preferably 15% by volume or more and 35% by
volume or less.
[0060] According to this, the antireflection film P2 can be made
relatively dense while making the antireflection function of the
antireflection film P2 particularly excellent, and the strength of
the antireflection film P2 and the durability of the optical
component P10 can be made particularly excellent.
[0061] The ratio of the silica particles P21 having a particle
diameter of 7.5 nm or more and 8.5 nm or less (the ratio of the
silica particles P21 falling within the third range R3) to the sum
of the volumes of the silica particles P21 constituting the
antireflection film P2 is preferably 30% by volume or more and 60%
by volume or less, more preferably 35% by volume or more and 55% by
volume or less.
[0062] According to this, the antireflection film P2 can be made
relatively dense while making the antireflection function of the
antireflection film P2 particularly excellent, and the strength of
the antireflection film P2 and the durability of the optical
component P10 can be made particularly excellent.
[0063] In the number-based particle size distribution, the range of
the particle diameter in which the first local maximum MV1 is
present may be 1.5 nm or more and 2.5 nm or less, but is preferably
1.6 nm or more and 2.4 nm or less, and more preferably 1.8 nm or
more and 2.2 nm or less.
[0064] According to this, the antireflection function of the
antireflection film P2 can be made particularly excellent.
[0065] In the number-based particle size distribution, the range of
the particle diameter in which the second local maximum MV2 is
present may be 3.5 nm or more and 4.5 nm or less, but is preferably
3.6 nm or more and 4.4 nm or less, and more preferably 3.8 nm or
more and 4.2 nm or less.
[0066] According to this, the antireflection function of the
antireflection film P2 can be made particularly excellent.
[0067] In the number-based particle size distribution, the range of
the particle diameter in which the third local maximum MV3 is
present may be 7.5 nm or more and 8.5 nm or less, but is preferably
7.6 nm or more and 8.4 nm or less, and more preferably 7.8 nm or
more and 8.2 nm or less.
[0068] According to this, the antireflection function of the
antireflection film P2 can be made particularly excellent.
[0069] The silica particles P21 may have the above-mentioned first
local maximum MV1, second local maximum MV2, and third local
maximum MV3 in the number-based particle size distribution, but
preferably have a fourth local maximum MV4 in the range of 5.5 nm
or more and 6.5 nm or less (a fourth range R4).
[0070] According to this, the antireflection function of the
antireflection film P2 can be made particularly excellent.
[0071] The ratio of the silica particles P21 having a particle
diameter of 5.5 nm or more and 6.5 nm or less (the ratio of the
silica particles P21 falling within the fourth range R4) to the sum
of the volumes of the silica particles P21 constituting the
antireflection film P2 is preferably 20% by volume or more and 30%
by volume or less, more preferably 22% by volume or more and 28% by
volume or less.
[0072] According to this, the antireflection film P2 can be made
relatively dense while making the antireflection function of the
antireflection film P2 particularly excellent, and the strength of
the antireflection film P2 and the durability of the optical
component P10 can be made particularly excellent.
[0073] In the number-based particle size distribution, the range of
the particle diameter in which the fourth local maximum MV4 is
present may be 5.5 nm or more and 6.5 nm or less, but is preferably
5.6 nm or more and 6.4 nm or less, and more preferably 5.8 nm or
more and 6.2 nm or less.
[0074] According to this, the antireflection function of the
antireflection film P2 can be made particularly excellent.
[0075] The number-based average particle diameter of the silica
particles P21 constituting the antireflection film P2 is not
particularly limited, but is preferably 0.5 nm or more and 4.0 nm
or less, more preferably 1.0 nm or more and 2.0 nm or less.
[0076] According to this, the antireflection film P2 can be made
relatively dense while making the antireflection function of the
antireflection film P2 particularly excellent, and the strength of
the antireflection film P2 and the durability of the optical
component P10 can be made particularly excellent.
[0077] In the embodiment of the invention, the measurement of the
particle size distribution can be performed by using various
methods, for example, a dynamic light scattering method, a laser
diffraction method, an image analysis method, a gravity
sedimentation method, and the like, but is preferably performed by
using a laser diffraction method.
[0078] According to this, the particle size distribution can be
obtained more easily. Further, in either case of a dry process or a
wet process, the measurement can be favorably performed, and a
relatively large amount of a sample can be treated at a time.
[0079] Examples of an apparatus which can be used for measuring the
particle size distribution include a single nanoparticle size
analyzer (IG-1000) manufactured by Shimadzu Corporation.
[0080] The content of the silica particles P21 in the
antireflection film P2 (the content thereof to the total solid
components) is preferably 80% by volume or more, more preferably
90% by volume or more and 99.5% by volume or less, further more
preferably 92% by volume or more and 99% by volume or less.
[0081] According to this, the antireflection function of the
antireflection film P2 can be made particularly excellent.
[0082] The antireflection film P2 may be any as long as it contains
the silica particles P21 having a particle size distribution as
described above, however, in the configuration shown in the
drawing, it contains conductive particles P22.
[0083] When the antireflection film P2 contains the conductive
particles P22 in this manner, an antistatic function is exhibited
in the optical component P10 as a whole. As a result, for example,
the adhesion of dust or the like due to static electricity can be
prevented, and thus, the optical component P10 can stably exhibit
the inherent optical property. Further, in the case where the
optical component P10 including such an antireflection film P2 is
used as a member for a timepiece such as a cover glass for a
timepiece, the deformation of a hand such as an hour hand due to
static electricity can be more reliably prevented. As a result, a
breakdown or the like of a timepiece including the member for a
timepiece can be more effectively prevented. Such an antistatic
function is obtained by using the silica particles P21 and the
conductive particles P22 in combination, and is not obtained, for
example, in the case where an antireflection film composed of a
multilayer film having a plurality of dense layers (layers formed
by a gas-phase deposition method) as in the related art and
conductive particles are used in combination.
[0084] The conductive particles P22 may be any as long as it is
composed of a material with electrical conductivity, however, the
volume resistivity of the constituent material of the conductive
particles P22 is preferably 100 .OMEGA.cm or less.
[0085] According to this, the antistatic property of the optical
component P10 can be made particularly excellent.
[0086] Further, the conductive particles P22 are preferably
composed of a transparent material.
[0087] According to this, the visibility through the optical
component P10 can be more reliably prevented from being adversely
affected.
[0088] Further, the conductive particles P22 are preferably
composed of a metal oxide. The metal oxide generally has excellent
chemical stability, and therefore can stably exhibit an antistatic
function over a long period of time, and thus, the durability of
the optical component P10 can be made particularly excellent.
[0089] Examples of the constituent material of the conductive
particles P22 satisfying the above-mentioned conditions include
In.sub.2O.sub.3, ZnO, CdO, Ga.sub.2O.sub.3, and SnO.sub.2,
materials obtained by doping any of the above-mentioned compounds
with tin (Sn), antimony (Sb), aluminum (Al), gallium (Ga), or the
like (for example, ITO (Sn-doped In.sub.2O.sub.3), AZO (Al-doped
ZnO), GZO (Ga-doped ZnO), and the like), and materials containing
two or more compounds selected therefrom (for example, IZO
(In.sub.2O.sub.3--ZnO), IGZO
(In.sub.2O.sub.3--Ga.sub.2O.sub.3--ZnO), and the like). Above all,
as the constituent material of the conductive particles P22,
SnO.sub.2 is preferred. SnO.sub.2 not only has high transparency,
but also has a relatively low refractive index, and therefore, has
a few effects on the antireflection property. Further, SnO.sub.2 is
relatively inexpensive, and SnO.sub.2 particles having a particle
diameter as described later can be easily and stably obtained.
[0090] The number-based average particle diameter of the conductive
particles P22 is not particularly limited, but is preferably 0.3 nm
or more and 10 nm or less, more preferably 0.7 nm or more and 6.0
nm or less, furthermore preferably 1.0 nm or more and 3.0 nm or
less.
[0091] According to this, the antistatic function can be made
particularly excellent while making the antireflection function of
the antireflection film P2 excellent. Further, the antireflection
film P2 can be made relatively dense, and the strength of the
antireflection film P2 and the durability of the optical component
P10 can be made particularly excellent.
[0092] When the number-based average particle diameter of the
silica particles P21 is represented by Ds (nm) and the number-based
average particle diameter of the conductive particles P22 is
represented by Dc (nm), it is preferred to satisfy the following
relationship: 0.1.ltoreq.Dc/Ds.ltoreq.0.6, it is more preferred to
satisfy the following relationship: 0.2.ltoreq.Dc/Ds.ltoreq.0.5,
and it is further more preferred to satisfy the following
relationship: 0.3.ltoreq.Dc/Ds.ltoreq.0.4.
[0093] By satisfying such a relationship, a mixing state of the
silica particles P21 and the conductive particles P22 in the
antireflection film P2 can be made more favorable, and the
antistatic function of the optical component P10 can be made
particularly excellent. Further, the antireflection film P2 can be
made relatively dense, and the strength of the antireflection film
P2 and the durability of the optical component P10 can be made
particularly excellent. In addition, the antireflection function
and the like of the antireflection film P2 can also be made
particularly excellent.
[0094] The content of the conductive particles P22 in the
antireflection film P2 (the content thereof to the total solid
components) is preferably 0.5% by volume or more and 10% by volume
or less, more preferably 1.0% by volume or more and 8.0% by volume
or less.
[0095] According to this, the antistatic function can be made
particularly excellent while making the antireflection function of
the antireflection film P2 excellent. Further, the antireflection
film P2 can be made relatively dense, and the strength of the
antireflection film P2 and the durability of the optical component
P10 can be made particularly excellent.
[0096] When the content of the silica particles P21 in the
antireflection film P2 (the content thereof to the total solid
components) is represented by Xs (vol %) and the content of the
conductive particles P22 in the antireflection film P2 (the content
thereof to the total solid components) is represented by Xc (vol
%), it is preferred to satisfy the following relationship:
0.003.ltoreq.Xc/Xs.ltoreq.0.12, and it is more preferred to satisfy
the following relationship: 0.005.ltoreq.Xc/Xs.ltoreq.0.1.
[0097] According to this, the antistatic function can be made
particularly excellent while making the antireflection function of
the antireflection film P2 excellent. Further, the antireflection
film P2 can be made relatively dense, and the strength of the
antireflection film P2 and the durability of the optical component
P10 can be made particularly excellent.
[0098] The antireflection film P2 may contain a component other
than the above-mentioned components.
[0099] Examples of such a component include an antifungal agent, a
preservative, an antioxidant, an ultraviolet absorber, a binder,
and a slipping agent (leveling agent).
[0100] The porosity of the antireflection film P2 is preferably 15%
by volume or more and 36% by volume or less, more preferably 18% by
volume or more and 32% by volume or less.
[0101] According to this, the antireflection function can be made
particularly excellent while making the durability of the optical
component P10 as a whole sufficiently excellent. In this manner,
the reason why the antireflection film has a particularly excellent
antireflection function is because in the antireflection film P2,
pores (air layers (refractive index: 1.00)) are present along with
a region occupied by the silica particles P21 (refractive index:
1.46) at a given ratio, so that the refractive index is decreased
as compared with silica in a bulk form, and as a result, a
favorable optical interference effect is obtained. Further, in the
case where the antireflection film P2 contains the conductive
particles P22, the antistatic function as described above is more
remarkably exhibited.
[0102] The porosity of the antireflection film P2 refers to the
ratio of pores accounting for the entire volume of the
antireflection film P2, and the pore encompasses not only a space
provided among particles constituting the antireflection film P2,
but also a hole provided inside the particle.
[0103] The surface roughness Ra of the antireflection film P2 is
preferably 0.5 nm or more and 10.0 nm or less, more preferably 0.7
nm or more and 6.0 nm or less.
[0104] According to this, the antifogging property of the optical
component P10 can be made particularly excellent while making the
light transmittance of the optical component P10 as a whole
sufficiently excellent.
[0105] The thickness of the antireflection film P2 is preferably 50
nm or more and 120 nm or less, more preferably 60 nm or more and
100 nm or less.
[0106] According to this, the durability, antireflection function,
and the like of the optical component P10 can be made particularly
excellent while effectively preventing the optical property of the
optical component P10 from being adversely affected.
[0107] Examples of the optical component include various lenses
(including microlenses, lenticular lenses, fresnel lenses, and the
like) such as projector lenses, camera lenses, and eyeglass lenses,
filters (camera low-pass filters, and the like), light transmitting
plates, dust-proof glasses, radiator plates, cover glasses for
timepieces, rear lids for timepieces, and light transmitting dial
plates (for example, dial plates for solar timepieces).
[0108] Among these, the optical component is preferably a cover
glass for a timepiece.
[0109] The cover glass is present at a place close to the viewpoint
of an observer (a user or the like) at the time of using a
timepiece, and also time-displaying members such as a dial plate
and hands are generally disposed on a rear surface side of the
cover glass, and therefore, the cover glass (optical component) is
a member which is strongly required to have visibility of a dial
plate and the like through the cover glass (optical component).
Therefore, in the case where the invention with which a high
antireflection function is exhibited is applied to a cover glass,
the effect of the invention is more remarkably exhibited.
[0110] Further, the cover glass is a component which has many
opportunities to be visually recognized by an observer (a user or
the like), and has a large influence on the appearance of the
entire timepiece. In the embodiment of the invention, a high
antireflection function is exhibited, and therefore, the excellent
appearance (aestheticity) inherent in an ornamental component such
as a dial plate which is visually recognized through the cover
glass can be effectively exhibited. Therefore, by applying the
embodiment of the invention to a cover glass for a timepiece, the
aesthetic appearance of the timepiece as a whole can be made
particularly excellent.
[0111] Further, in a diver's watch or the like, liquid tightness in
a case is maintained, however, a humidity contained in the case
when assembling the watch is dew-condensed during use to cause a
problem of decreasing the visibility in some cases. However,
according to the embodiment of the invention, the antireflection
film has a high antireflection function and also has a high
antifogging property, and therefore, for example, in a diver's
watch, by disposing a cover glass (optical component), to which the
embodiment of the invention is applied, such that a surface
provided with the antireflection film faces the inner surface side,
the problem of dew condensation as described above can be more
reliably prevented.
Second Embodiment
[0112] FIG. 3 is a cross-sectional view schematically showing a
second embodiment of the optical component according to the
invention. In the following description, different points from the
above embodiment will be mainly described, and the description of
the same matter will be omitted.
[0113] As shown in FIG. 3, an optical component P10 of this
embodiment includes abase material P1, an antireflection film P2
containing silica particles P21, and a foundation layer P3.
[0114] In this manner, by including the foundation layer P3, for
example, the adhesiveness between the base material P1 and the
antireflection film P2 (the adhesiveness through the foundation
layer P3) can be made particularly excellent, and thus, the
durability and reliability of the optical component P10 can be made
particularly excellent.
[0115] Examples of a constituent material of the foundation layer
P3 include various resin materials and SiO.sub.2.
[0116] The thickness of the foundation layer P3 is not particularly
limited, but is preferably 5 nm or more and 25 nm or less, more
preferably 10 nm or more and 20 nm or less.
[0117] In the configuration shown in the drawing, only one
foundation layer P3 is formed, however, the optical component P10
may include a plurality of foundation layers between the base
material P1 and the antireflection film P2.
Method for Producing Optical Component
[0118] Next, a method for producing the optical component will be
described.
[0119] The optical component P10 may be produced by any method, but
can be favorably produced by, for example, using a method including
a base material preparation step (1a) of preparing a base material
P1, an antireflection film forming composition application step
(1b) of applying an antireflection film forming composition
containing silica particles P21 and a dispersion medium for
dispersing the silica particles P21 onto the base material P1, and
a dispersion medium removal step (1c) of removing the dispersion
medium from the antireflection film forming composition applied
onto the base material P1.
Base Material Preparation Step
[0120] In this step, a base material P1 is prepared (1a).
[0121] As the base material P1, a material described above can be
used, however, a material subjected to a pretreatment such as a
washing treatment or a lyophilization treatment may be used.
Further, as the pretreatment, a mask may be formed in a region
where the antireflection film P2 is not desired to be formed. In
this case, as a post-treatment step, a mask removal step may be
included.
Antireflection Film Forming Composition Application Step
[0122] In this step, an antireflection film forming composition
containing silica particles P21 and a dispersion medium for
dispersing the silica particles P21 is applied onto the base
material P1 (1b).
[0123] Such an antireflection film forming composition contains a
dispersion medium and has excellent fluidity, and therefore, the
antireflection film P2 in which an undesirable variation in the
thickness is more effectively prevented can be easily and reliably
formed.
[0124] Examples of the method for applying the antireflection film
forming composition onto the base material P1 include various
printing methods such as an inkjet method, various coating methods
such as roll coating, spray coating, spin coating, and brush
coating, and dipping (a dipping method).
[0125] The dispersion medium constituting the antireflection film
forming composition may be any as long as it has a function to
disperse the silica particles P21, however, examples thereof
include water; alcohol-based solvents such as methanol, ethanol,
isopropanol, ethylene glycol, propylene glycol, and glycerin;
ketone-based solvents such as methyl ethyl ketone and acetone;
glycol ether-based solvents such as ethylene glycol monoethyl ether
and ethylene glycol monobutyl ether; glycol ether acetate-based
solvents such as propylene glycol 1-monomethyl ether 2-acetate and
propylene glycol 1-monoethyl ether 2-acetate; polyethylene glycol
and polypropylene glycol, and one type or a combination of two or
more types selected from these solvents can be used.
[0126] Among these, as the dispersion medium, water, an
alcohol-based solvent, or a glycol-based solvent (in addition to a
glycol such as ethylene glycol or propylene glycol, a compound such
as an ether, an ester, or the like of a glycol such as a glycol
ether-based solvent or a glycol ether acetate-based solvent) is
preferred.
[0127] According to this, the dispersion stability of the silica
particles P21 and the like in the antireflection film forming
composition can be made particularly excellent, and the occurrence
of an undesirable variation in the composition in the
antireflection film P2 to be formed and an undesirable variation in
the thickness thereof can be more effectively prevented.
[0128] In particular, in the case where the antireflection film
forming composition is applied by a method such as roll coating or
spin coating, it is preferred to use water or an alcohol-based
solvent as the dispersion medium.
[0129] According to this, the coatability of the antireflection
film forming composition on the base material P1 can be made
particularly excellent.
[0130] In the case where the antireflection film forming
composition is applied by a method such as spray coating, it is
preferred to use a glycol-based solvent as the dispersion
medium.
[0131] According to this, the coatability of the antireflection
film forming composition onto the base material P1 can be made
particularly excellent. Further, clogging can be prevented, and
thus, the productivity and the like of the optical component P10
can be made particularly high.
[0132] The antireflection film forming composition may contain a
component (another component) other than the silica particles P21
and the dispersion medium. Examples of such a component (another
component) include conductive particles, an antifungal agent, a
preservative, an antioxidant, an ultraviolet absorber, a binder,
and a slipping agent (leveling agent).
[0133] The content of the silica particles P21 in the
antireflection film forming composition is not particularly
limited, but is preferably 0.5% by mass or more and 10% by mass or
less.
[0134] According to this, the fluidity of the antireflection film
forming composition can be made favorable, and the occurrence of an
undesirable variation in the thickness or the like in the
antireflection film P2 to be formed can be more effectively
prevented, and also the efficiency of forming the antireflection
film P2 can be made particularly excellent, and thus, the
productivity of the optical component P10 can be made particularly
high.
[0135] The content of the dispersion medium in the antireflection
film forming composition is not particularly limited, but is
preferably 90% by mass or more and 99.5% by mass or less.
[0136] According to this, the fluidity of the antireflection film
forming composition can be made favorable, and the occurrence of an
undesirable variation in the thickness or the like in the
antireflection film P2 to be formed can be more effectively
prevented, and also the efficiency of forming the antireflection
film P2 can be made particularly excellent, and thus, the
productivity of the optical component P10 can be made particularly
high.
[0137] The viscosity of the antireflection film forming composition
in this step as measured according to JIS Z 8809 using a
vibration-type viscometer is preferably 20 mPas or less, more
preferably 3 mPas or more and 15 mPas or less.
[0138] According to this, the application of the antireflection
film forming composition onto the base material P1 can be favorably
performed, and the occurrence of an undesirable variation in the
thickness or the like in the antireflection film P2 to be formed
can be more effectively prevented, and also the efficiency of
forming the antireflection film P2 can be made particularly
excellent, and thus, the productivity of the optical component P10
can be made particularly high.
Dispersion Medium Removal Step
[0139] In this step, the dispersion medium is removed from the
antireflection film forming composition applied onto the base
material P1 (1c).
[0140] According to this, the antireflection film P2 strongly
bonded to the base material P1 is formed. In particular, the
antireflection film forming composition contains particles (silica
particles P21) as a constituent component of the antireflection
film P2.
[0141] Due to this, when the dispersion medium is removed in this
step, the occurrence of a phenomenon that the dispersion medium is
undesirably enclosed in the antireflection film P2 to be formed so
that the dispersion medium undesirably remains in the optical
component P10 to be finally obtained can be reliably prevented. As
a result, the optical property and reliability of the optical
component P10 can be reliably made excellent. Further, since the
antireflection film forming composition contains particles (silica
particles P21) as a constituent component of the antireflection
film P2, the dispersion medium contained in the antireflection film
forming composition in the form of a film can be maintained in a
state where it communicates with the outside constantly in this
step, and therefore, the dispersion medium can be efficiently
removed from the antireflection film forming composition in the
form of a film. As a result, the productivity of the optical
component P10 can be made high.
[0142] This step can be performed by, for example, a heating
treatment, a vacuum treatment, an air blowing treatment, or the
like, and two or more treatments selected therefrom may be
performed in combination.
[0143] In the case where this step is performed by a heating
treatment, the heating temperature is preferably 50.degree. C. or
higher and 200.degree. C. or lower, more preferably 60.degree. C.
or higher and 180.degree. C. or lower. Further, the heating
temperature in this step is preferably lower than the boiling point
of the dispersion medium of the antireflection film forming
composition.
[0144] According to this, the antireflection film P2 can be
efficiently formed while preventing undesirable deterioration,
denaturation, or the like of the material, or undesirable
deformation or the like of the antireflection film P2 or the
like.
[0145] In the case where this step is performed by a vacuum
treatment, the pressure during the vacuum treatment (the pressure
of the environment in which the base material P1 having the
antireflection film forming composition applied thereon is placed)
is preferably 1.times.10.sup.2 Pa or less, more preferably
1.times.10.sup.1 Pa or less.
[0146] According to this, the productivity of the optical component
P10 can be made particularly high. Further, the occurrence of an
adverse effect caused by the dispersion medium remaining in the
finally obtained optical component P10 can be more reliably
prevented.
[0147] In this step, for example, two or more treatments under
different conditions may be performed.
[0148] For example, a first heating treatment which is performed at
a relatively low temperature and a second heating treatment which
is performed at a higher temperature than in the first heating
treatment may be performed. According to this, while more
effectively preventing the occurrence of a defect (for example, the
occurrence of a relatively large pore, undesirable deformation of
the antireflection film P2, or the like) or the like in the
antireflection film P2 to be formed, the efficiency of forming the
antireflection film P2 can be made particularly excellent.
[0149] The antireflection film forming composition application step
and the dispersion medium removal step may be performed repeatedly.
According to this, even an antireflection film having a relatively
large thickness can be favorable formed. In addition, the
antireflection film P2 can be favorably formed at a plurality of
places on the base material P1. For example, even in the case where
the antireflection film P2 is formed at a plurality of places where
it is difficult to apply the antireflection film forming
composition by performing a single antireflection film forming
composition application step, or in the case where the
antireflection films P2 having a different condition, for example,
having a different thickness are formed, etc., this production
method can be favorably applied.
[0150] Further, as shown in FIG. 3, in the case where the optical
component P10 having the foundation layer P3 between the base
material P1 and the antireflection film P2 is produced, for
example, by providing a foundation layer forming material
application step of applying a foundation layer forming material
onto the base material P1 prior to the antireflection film forming
composition application step, the optical component P10 can be
favorably produced.
[0151] In the case where the foundation layer P3 containing a resin
material is formed, as the foundation layer forming material, a
material obtained by dissolving the resin material in a solvent, a
liquid composition containing a precursor (for example, a monomer,
a dimer, a trimer, an oligomer, a prepolymer, or the like) of the
resin material can be used.
[0152] In the case where such a material is used, examples of the
method for applying the foundation layer forming material include
various printing methods such as an inkjet method, various coating
methods such as roll coating, spray coating, spin coating, and
brush coating, and dipping (a dipping method).
[0153] Further, in the case where the foundation layer P3 composed
of, for example, SiO.sub.2 is formed, a foundation layer formation
step of forming the foundation layer P3 on the surface of the base
material P1 by a gas-phase deposition method (for example, a vapor
deposition method) may be provided prior to the antireflection film
forming composition application step. According to this, the
adhesiveness between the base material P1 and the foundation layer
P3 can be made particularly excellent, and also the transparency of
the foundation layer P3 can be made particularly high, and thus,
the optical property of the optical component P10 as a whole can be
further enhanced.
[0154] According to the production method as described above, an
optical component including an antireflection film having an
excellent antireflection function with a simple structure can be
efficiently produced.
Timepiece
[0155] Next, a timepiece according to the invention will be
described.
[0156] The timepiece according to the invention includes the
optical component according to the invention as described
above.
[0157] According to this, a timepiece capable of favorably visually
recognizing a state on a rear surface side of the optical component
can be provided, and the aesthetic appearance (aestheticity) of the
timepiece as a whole can be made excellent, and thus, the value as
an ornament can be increased. In addition, for example, the
visibility of the time and the like can be improved, and therefore,
also the function (practicality) as a utility article becomes
excellent.
[0158] The timepiece according to the invention may be any as long
as it includes the optical component according to the invention as
at least one optical component, and as the other components, known
components can be used, however, hereinafter, one example of the
configuration of the timepiece when the optical component according
to the invention is applied to the cover glass will be
representatively described.
[0159] FIG. 4 is a partial cross-sectional view showing a preferred
embodiment of the timepiece (wristwatch) according to the
invention.
[0160] As shown in FIG. 4, a wristwatch (portable timepiece) P100
of this embodiment includes a barrel (case) P82, a rear lid P83, a
bezel (frame) P84, and a cover glass (a cover glass for a
timepiece) P85. In the case P82, a dial plate for a timepiece (a
dial plate) P7, a solar cell P94, and a movement P81 are housed,
and further, hands (indicator hands) not shown in the drawing and
the like are also housed.
[0161] The cover glass P85 is composed of the optical component
according to the invention as described above.
[0162] According to this, the visibility of the dial plate P7, the
hands (indicator hands), and the like can be enhanced. Further, the
dial plate P7 and the like are members which have a large influence
on the appearance of the entire timepiece, however, undesirable
light reflection when the dial plate P7 and the like are visually
recognized is prevented, and therefore, the aesthetic appearance
(aestheticity) of the timepiece as a whole can be made particularly
excellent.
[0163] The movement P81 drives the indicator hands by utilizing the
electromotive force of the solar cell P94.
[0164] Although not shown in FIG. 4, in the movement P81, for
example, an electric double-layer capacitor which stores the
electromotive force of the solar cell P94, a lithium ion secondary
buttery, a crystal oscillator as a time reference source, a
semiconductor integrated circuit which generates a driving pulse
for driving the timepiece based on the oscillation frequency of the
crystal oscillator, a step motor for driving the indicator hands
every second by receiving this driving pulse, a gear train
mechanism for transmitting the movement of the step motor to the
indicator hands, and the like are included.
[0165] Further, the movement P81 includes an antenna for receiving
a radio wave (not shown), and has a function to perform time
adjustment and the like using the received radio wave.
[0166] The solar cell P94 has a function to convert light energy
into electrical energy. The electrical energy converted by the
solar cell P94 is utilized for driving the movement P81 or the
like.
[0167] The solar cell P94 has, for example, a PIN structure in
which a p-type impurity and an n-type impurity are selectively
introduced into a non-single crystal silicon thin film, and
further, an i-type non-single crystal silicon thin film having a
low impurity concentration is provided between a p-type non-single
crystal silicon thin film and an n-type non-single crystal silicon
thin film.
[0168] In the barrel P82, a winding stem pipe P86 is fitted and
fixed, and in this winding stem pipe P86, a shaft P871 of a stern
P87 is rotatably inserted.
[0169] The barrel P82 and the bezel P84 are fixed to each other
with a plastic packing P88, and the bezel P84 and the cover glass
P85 are fixed to each other with a plastic packing P89.
[0170] In the barrel P82, the rear lid P83 is fitted (or threadedly
engaged), and in a joint portion (seal portion) P93 of these
members, a ring-shaped rubber packing (rear lid packing) P92 is
inserted in a compressed state. According to this configuration,
the seal portion P93 is sealed in a liquid-tight manner, whereby a
water-proof function is obtained.
[0171] A groove P872 is formed in a middle part on an outer
periphery of the shaft P871 of the stem P87, and in this groove
P872, a ring-shaped rubber packing (stem packing) P91 is fitted.
The rubber packing P91 is in close contact with the inner
peripheral surface of the winding stem pipe P86 and compressed
between the inner peripheral surface and the inner surface of the
groove P872. According to this configuration, liquid-tight sealing
is provided between the stem P87 and the winding stem pipe P86, so
that a water-proof function is obtained. Incidentally, when the
stem P87 is rotated, the rubber packing P91 rotates along with the
shaft P871 and slides in the circumferential direction while being
in close contact with the inner peripheral surface of the winding
stem pipe P86.
[0172] In the above description, as one example of the timepiece, a
timepiece including a cover glass as the optical component
according to the invention has been described, however, the
timepiece according to the invention may be a timepiece including,
for example, a component to which the optical component according
to the invention is applied as the component other than the cover
glass. For example, the rear lid or the like may be one composed of
the optical component according to the invention. According to
this, the effect as described above can be obtained, and also the
aesthetic appearance (aestheticity) of the timepiece as a whole can
be improved.
[0173] Further, in the above description, as one example of the
timepiece, a wristwatch (portable timepiece) as a solar radio
timepiece has been described, however, the invention can also be
applied to other types of timepieces such as portable timepieces
other than wristwatches, table clocks, and wall clocks in the same
manner. Further, the invention can also be applied to any
timepieces such as solar timepieces other than solar radio
timepieces and radio timepieces other than solar radio
timepieces.
[0174] Hereinabove, preferred embodiments of the invention have
been described, however, the invention is not limited to those
described above.
[0175] For example, in the optical component and the timepiece
according to the invention, the configuration of each part can be
replaced with an arbitrary configuration exhibiting a similar
function, and also an arbitrary configuration can be added.
[0176] For example, the optical component may include a protective
film or the like in addition to the base material and the
antireflection film.
[0177] Further, the optical component according to the invention
may include a plurality of antireflection films. For example, in
the above-mentioned embodiment, a case where the antireflection
film is provided on one surface side of the base material has been
described, however, the antireflection film may be provided on both
surface sides of the base material. Further, the optical component
may have a configuration in which a plurality of antireflection
films are stacked on one another through an intermediate layer.
[0178] Further, in the above-mentioned embodiment, a case where the
optical component according to the invention is used as a
constituent component of a timepiece has been mainly described,
however, the optical component according to the invention is not
limited to an optical component to be used as a constituent
component of a timepiece, and may be an optical component to be
applied to, for example, various electrical devices including
optical devices such as cameras (including video cameras, cameras
mounted on cellular phones (including smart phones, PHS, etc.), and
the like) and projectors, optical measurement devices such as
microscopes, and the like, and also to eyeglasses, loupes, and the
like. Further, the optical component according to the invention is
not limited to an optical component to be used in combination with
another member, and may be an optical component to be used by
itself alone.
[0179] Further, in the production of the optical component
according to the invention, other than the above-mentioned steps,
according to need, a pretreatment step, an intermediate treatment
step, and a post-treatment step may be performed. For example,
prior to the antireflection film forming composition application
step, a step of performing UV irradiation, plasma irradiation, or
the like on the surface of the base material may be included.
According to this, for example, the wettability of the
antireflection film forming composition on the base material can be
made more favorable, and the antireflection film having a desired
condition (for example, a desired film thickness) can be more
favorably formed. Further, the adhesiveness between the base
material and the antireflection film is made particularly
excellent, and thus, the durability and reliability of the optical
component can be made particularly excellent.
[0180] Further, the optical component according to the invention is
not limited to those produced using the above-mentioned method. For
example, in the above-mentioned embodiment, a case where the
antireflection film is formed by using an antireflection film
forming composition containing a dispersion medium in addition to
silica particles has been described, however, for example, as the
antireflection film forming composition, a composition containing
no dispersion medium may be used.
EXAMPLES
[0181] Next, specific examples of the invention will be
described.
1. Production of Optical Component (Cover Glass)
Example 1
[0182] By the method as described below, a cover glass as an
optical component was produced.
[0183] First, a plate material (glass plate) composed of a sapphire
glass was prepared as a base material (the base material
preparation step), and a necessary part was cut and polished. The
base material obtained by cutting and polishing had a substantially
disk shape and had a size of 30 mm in diameter and 1 mm in
thickness.
[0184] Subsequently, a UV irradiation treatment in which an
ultraviolet ray with a wavelength of 248 nm was irradiated on the
surface of the base material on the side where an antireflection
film was going to be formed.
[0185] Subsequently, an antireflection film forming composition was
applied onto the entire surface of one side of the base material by
a spray coating method (antireflection film forming composition
application step).
[0186] As the antireflection film forming composition, a
composition obtained by mixing silica particles, tin oxide
(SnO.sub.2) particles (number-based average particle diameter: 2.0
nm) as conductive particles (conductive transparent metal oxide
particles), and methanol as a dispersion medium at a given ratio
was used.
[0187] As the silica particles, silica particles which have a first
local maximum in the range of 1.5 nm or more and 2.5 nm or less (a
first range), a second local maximum in the range of 3.5 nm or more
and 4.5 nm or less (a second range), and a third local maximum in
the range of 7.5 nm or more and 8.5 nm or less (a third range), and
a fourth local maximum in the range of 5.5 nm or more and 6.5 nm or
less (a fourth range) in a number-based particle size distribution,
and also have a number-based average particle diameter of 2.6 nm
were used.
[0188] Thereafter, the base material onto which the antireflection
film forming composition was applied was left to stand in an
environment at 1.times.10.sup.-4 Pa to remove the dispersion medium
constituting the antireflection film forming composition
(dispersion medium removal step), whereby the antireflection film
was formed.
[0189] The average thickness of the formed antireflection film was
80 nm and the porosity was 26% by volume. Further, the surface
roughness Ra of the outer surface (the surface on an opposite side
to the surface facing the base material) of the antireflection film
was 1.3 nm.
Examples 2 to 10
[0190] Optical components (cover glasses) were produced in the same
manner as in the above Example 1 except that the particle size
distribution of the silica particles constituting the
antireflection film forming composition was changed as shown in
Table 1, and the configuration of the antireflection film forming
composition and the configurations of the respective parts of the
optical component were changed as shown in Table 2.
Example 11
[0191] An optical component (cover glass) was produced in the same
manner as in the above Example 1 except that prior to the
antireflection film forming composition application step, a
foundation layer composed of SiO.sub.2 was formed on the surface of
the base material (the surface on the side where the antireflection
film was going to be formed) (the foundation layer formation
step).
[0192] The formation of the foundation layer was performed by
vacuum vapor deposition. The thickness of the formed foundation
layer was 15 nm.
Examples 12 to 14
[0193] Optical components (cover glasses) were produced in the same
manner as in the above Example 11 except that the particle size
distribution of the silica particles constituting the
antireflection film forming composition was changed as shown in
Table 1, and the configuration of the antireflection film forming
composition and the configurations of the respective parts of the
optical component were changed as shown in Table 2.
Comparative Example 1
[0194] An optical component (cover glass) was produced in the same
manner as in the above Example 2 except that the base material (the
plate material composed of a sapphire glass) was directly used as
the optical component without forming an antireflection film on the
base material.
Comparative Examples 2 to 4
[0195] Optical components (cover glasses) were produced in the same
manner as in the above Example 2 except that the particle size
distribution of the silica particles constituting the
antireflection film forming composition was changed as shown in
Table 1.
Comparative Example 5
[0196] An optical component (cover glass) was produced in the same
manner as in the above Example 2 except that an anionic surfactant
was used as the antireflection film forming composition and the
antireflection film was formed as a film composed of a polymeric
organic material.
[0197] The particle size distributions of the silica particles
constituting the antireflection film forming compositions used in
the production of the optical components (cover glasses) of the
respective Examples and Comparative Examples are shown in Table 1,
and the configurations of the antireflection film forming
compositions used in the production of the optical components
(cover glasses) of the respective Examples and Comparative Examples
and the configurations of the respective parts of the optical
components (cover glasses) of the respective Examples and
Comparative Examples are shown in Table 2. Incidentally, in Tables
1 and 2, in the column of "average particle diameter", the value of
the number-based average particle diameter is shown. Further, in
the above respective Examples and Comparative Examples, the
particle size distribution of the particles was determined by laser
diffractometry using a single nanoparticle size analyzer IG-1000
(manufactured by Shimadzu Corporation). Further, the viscosities
(viscosities in the antireflection film forming composition
application step) of the antireflection film forming compositions
used in the above respective Examples and Comparative Examples as
measured according to JIS Z 8809 using a vibration-type viscometer
were all in the range of 3 mPas or more and 15 mPas or less.
TABLE-US-00001 TABLE 1 First range Second range Third range
Particle Ratio of silica Presence or Particle Ratio of silica
Presence or Presence or diameter of first particles falling absence
of diameter of particles falling absence of absence of first local
maximum within first second local second local within second third
local local maximum (nm) range (vol %) maximum maximum (nm) range
(vol %) maximum Example 1 presence 2.0 15 presence 4.0 20 presence
Example 2 presence 2.0 15 presence 4.0 20 presence Example 3
presence 2.0 15 presence 4.0 20 presence Example 4 presence 2.0 15
presence 4.0 20 presence Example 5 presence 2.0 20 presence 4.0 30
presence Example 6 presence 2.0 30 presence 4.0 20 presence Example
7 presence 2.0 20 presence 4.0 40 presence Example 8 presence 2.0
20 presence 4.0 20 presence Example 9 presence 2.0 15 presence 4.0
20 presence Example 10 presence 2.0 15 presence 4.0 20 presence
Example 11 presence 2.0 15 presence 4.0 20 presence Example 12
presence 2.0 15 presence 4.0 20 presence Example 13 presence 2.0 15
presence 4.0 20 presence Example 14 presence 2.0 15 presence 4.0 20
presence Comparative -- -- -- -- -- -- -- Example 1 Comparative
absence -- -- presence 4.0 40 presence Example 2 Comparative
presence 2.0 20 absence -- -- presence Example 3 Comparative
presence 2.0 40 presence 4.0 60 absence Example 4 Comparative -- --
-- -- -- -- -- Example 5 Third range Fourth range Particle Ratio of
silica Presence or Particle Ratio of silica Average diameter of
particles falling absence of diameter of particles falling particle
third local within third fourth local fourth local within fourth
diameter maximum (nm) range (vol %) maximum maximum (nm) range (vol
%) (nm) Example 1 8.0 40 presence 6.0 25 2.6 Example 2 8.0 40
presence 6.0 25 2.6 Example 3 8.0 40 presence 6.0 25 2.6 Example 4
8.0 40 presence 6.0 25 2.6 Example 5 8.0 50 absence -- -- 2.4
Example 6 8.0 50 absence -- -- 2.3 Example 7 8.0 40 absence -- --
2.5 Example 8 8.0 60 absence -- -- 2.5 Example 9 8.0 40 presence
6.0 25 2.6 Example 10 8.0 40 presence 6.0 25 2.6 Example 11 8.0 40
presence 6.0 25 2.6 Example 12 8.0 40 presence 6.0 25 2.6 Example
13 8.0 40 presence 6.0 25 2.6 Example 14 8.0 40 presence 6.0 25 2.6
Comparative -- -- -- -- -- -- Example 1 Comparative 8.0 60 absence
-- -- 4.6 Example 2 Comparative -- 80 absence -- -- 2.4 Example 3
Comparative -- -- absence -- -- 1.9 Example 4 Comparative -- -- --
-- -- -- Example 5
TABLE-US-00002 TABLE 2 Configuration Configuration of
antireflection film forming composition of optical Silica component
particles Conductive particles Dispersion medium Base material
Content Constituent Average particle Content Constituent Content
Constituent (mass %) material diameter (nm) (mass %) material (mass
%) material Example 1 2.0 SnO.sub.2 2.0 0.1 methanol 97.9 Sapphire
glass Example 2 2.0 -- -- -- methanol 98.0 Sapphire glass Example 3
2.0 SnO.sub.2 2.0 0.04 methanol 97.96 Sapphire glass Example 4 2.0
SnO.sub.2 2.0 0.5 methanol 97.5 Sapphire glass Example 5 2.0
SnO.sub.2 2.0 0.1 methanol 97.9 Sapphire glass Example 6 2.0
SnO.sub.2 2.0 0.1 methanol 97.9 Sapphire glass Example 7 2.0
SnO.sub.2 2.0 0.1 methanol 97.9 Sapphire glass Example 8 2.0
SnO.sub.2 2.0 0.1 methanol 97.9 Sapphire glass Example 9 2.0
SnO.sub.2 2.0 0.1 methanol 97.9 Sapphire glass Example 10 2.0
SnO.sub.2 2.0 0.1 methanol 97.9 Sapphire glass Example 11 2.0
SnO.sub.2 2.0 0.1 methanol 97.9 Sapphire glass Example 12 2.0 -- --
-- methanol 98.0 Sapphire glass Example 13 2.0 SnO.sub.2 2.0 0.1
methanol 97.9 Sapphire glass Example 14 2.0 SnO.sub.2 2.0 0.1
methanol 97.9 Sapphire glass Comparative -- -- -- -- -- Sapphire
glass Example 1 Comparative 2.0 -- -- -- methanol 98.0 Sapphire
glass Example 2 Comparative 2.0 -- -- -- methanol 98.0 Sapphire
glass Example 3 Comparative 2.0 -- -- -- methanol 98.0 Sapphire
glass Example 4 Comparative -- -- -- -- -- -- Sapphire glass
Example 5 Configuration of optical component Antireflection film
Foundation layer Surface Constituent Thickness Content Thickness
roughness Porosity material (nm) Constituent material (vol %) (nm)
Ra (nm) (vol %) Example 1 -- -- SiO.sub.2 particles/SnO.sub.2
particles 98.4/1.6 80 1.3 26 Example 2 -- -- SiO.sub.2 particles
100 80 1.3 26 Example 3 -- -- SiO.sub.2 particles/SnO.sub.2
particles 99.7/0.3 80 1.3 26 Example 4 -- -- SiO.sub.2
particles/SnO.sub.2 particles 92.6/7.4 80 1.3 25 Example 5 -- --
SiO.sub.2 particles/SnO.sub.2 particles 98.4/1.6 80 1.2 23 Example
6 -- -- SiO.sub.2 particles/SnO.sub.2 particles 98.4/1.6 80 1.2 18
Example 7 -- -- SiO.sub.2 particles/SnO.sub.2 particles 98.4/1.6 80
1.3 24 Example 8 -- -- SiO.sub.2 particles/SnO.sub.2 particles
98.4/1.6 80 1.3 32 Example 9 -- -- SiO.sub.2 particles/SnO.sub.2
particles 98.4/1.6 50 1.3 26 Example 10 -- -- SiO.sub.2
particles/SnO.sub.2 particles 98.4/1.6 120 1.3 26 Example 11
SiO.sub.2 15 SiO.sub.2 particles/SnO.sub.2 particles 98.4/1.6 80
1.2 26 Example 12 SiO.sub.2 15 SiO.sub.2 particles 100 80 1.2 26
Example 13 SiO.sub.2 5 SiO.sub.2 particles/SnO.sub.2 particles
98.4/1.6 80 1.3 26 Example 14 SiO.sub.2 25 SiO.sub.2
particles/SnO.sub.2 particles 98.4/1.6 80 1.1 26 Comparative -- --
-- -- -- -- -- Example 1 Comparative -- -- SiO.sub.2 particles 100
80 2.3 38 Example 2 Comparative -- -- SiO.sub.2 particles 100 80
1.2 17 Example 3 Comparative -- -- SiO.sub.2 particles 100 80 1.0
15 Example 4 Comparative -- -- Anionic surfactant 100 10 0.5 --
Example 5
2. Evaluation of Reflectance
[0198] With respect to each of the cover glasses produced in the
above respective Examples and Comparative Examples, the light
reflectance from the cover glass was measured from the surface on
the opposite side to the surface on which the antireflection film
was provided of the base material using a reflectometer USPM
manufactured by Olympus Corporation, and evaluation was performed
according to the following criteria. Incidentally, in the case of
Comparative Example 1, the antireflection film was not provided on
both surfaces, and therefore, evaluation was performed for
arbitrarily selected one surface (the same shall apply also to the
following evaluation items).
[0199] A: The light reflectance is less than 0.3%.
[0200] B: The light reflectance is 0.3% or more and less than
0.5%.
[0201] C: The light reflectance is 0.5% or more and less than
1.0%.
[0202] D: The light reflectance is 1.0% or more and less than
4.0%.
[0203] E: The light reflectance is 4.0% or more.
3. Evaluation of Antifogging Property
[0204] The antifogging property evaluation index when saturated
water vapor was sprayed onto the surface on the side where the
antireflection film was provided of each of the cover glasses
produced in the above respective Examples and Comparative Examples
was obtained by using an antifogging property evaluation device
(AFA-1 manufactured by Kyowa Interface Science Co., Ltd.), and
evaluation was performed according to the following criteria. It
can be said that as the antifogging property evaluation index is
lower, the antifogging property is superior.
[0205] A: The antifogging property evaluation index is less than
3.
[0206] B: The antifogging property evaluation index is 3 or more
and less than 6.
[0207] C: The antifogging property evaluation index is 6 or more
and less than 10.
[0208] D: The antifogging property evaluation index is 10 or more
and less than 20.
[0209] E: The antifogging property evaluation index is 20 or
more.
4. Evaluation of Antistatic Property
[0210] A probe was brought into contact with the surface on the
side where the antireflection film was provided of each of the
cover glasses produced in the above respective Examples and
Comparative Examples, and the surface electrical resistance was
measured by using a surface resistance meter (Hiresta-UP MCP-HT45
manufactured by Mitsubishi Chemical Corporation), and evaluation
was performed according to the following criteria. It can be said
that as the surface electrical resistance is lower, the antistatic
property is superior. The measurement was performed in an
environment in which the temperature was 25.degree. C. and the
humidity was 55% RH.
[0211] A: The surface electrical resistance is less than 1E+8
.OMEGA./.quadrature..
[0212] B: The surface electrical resistance is
1E+8.OMEGA./.quadrature. or more and less than 1E+9
.OMEGA./.quadrature..
[0213] C: The surface electrical resistance is
1E+9.OMEGA./.quadrature. or more and less than 1E+11
.OMEGA./.quadrature..
[0214] D: The surface electrical resistance is
1E+11.OMEGA./.quadrature. or more and less than 1E+15
.OMEGA./.quadrature..
[0215] E: The surface electrical resistance is
1E+15.OMEGA./.quadrature. or more.
5. Evaluation of Adhesiveness
[0216] Five horizontal cut lines at 2 mm intervals and five
vertical cut lines at 2 mm intervals were provided on the surface
to be evaluated with a cutter, and an adhesive tape (CT-18
manufactured by Nichiban Co., Ltd.) was adhered thereto, and
thereafter, the adhesive tape was peeled off at a stroke. Then, it
was confirmed whether or not peeling occurred on the surface to be
evaluated by visual observation, and evaluation was performed
according to the following criteria.
[0217] A: No film peeling is observed.
[0218] B: The percentage of the area where film peeling occurred is
less than 5%.
[0219] C: The percentage of the area where film peeling occurred is
5% or more and less than 20%.
[0220] D: The percentage of the area where film peeling occurred is
20% or more and less than 50%.
[0221] E: The percentage of the area where film peeling occurred is
50% or more.
6. Evaluation of Abrasion Resistance
[0222] An abrasion resistance test using silbon paper as a counter
paper was performed according to JIS K 5701 for the surface on the
side where the antireflection film was provided of each of the
cover glasses produced in the above respective Examples and
Comparative Examples. Then, the cover glass after the abrasion
resistance test was visually observed, and evaluation was performed
according to the following criteria.
[0223] A: No scratches by rubbing occur.
[0224] B: Almost no scratches by rubbing occur.
[0225] C: Scratches by rubbing slightly occur.
[0226] D: Scratches by rubbing clearly occur.
[0227] E: Scratches by rubbing remarkably occur.
7. Production of Timepiece
[0228] By using each of the cover glasses produced in the above
respective Examples and Comparative Examples, wristwatches as shown
in FIG. 4 were produced. At this time, the surface on the side
where the antireflection film was provided of the cover glass was
disposed facing the inner surface side (a side facing the dial
plate and the like).
8. Evaluation of Visibility of Dial Plate of Timepiece
[0229] With respect to each of the timepieces produced in the above
respective Examples and Comparative Examples, the dial plate and
the like were observed through the cover glass, and the visibility
at that time was evaluated according to the following criteria.
[0230] A: The visibility of the dial plate and the like is very
high.
[0231] B: The visibility of the dial plate and the like is
high.
[0232] C: The visibility of the dial plate and the like is within
the acceptable range.
[0233] D: The visibility of the dial plate and the like is somewhat
low.
[0234] E: The visibility of the dial plate and the like is very
low.
[0235] These results are shown in Table 3.
TABLE-US-00003 TABLE 3 Antifogging Antistatic Abrasion Visibility
of Reflectance property property Adhesiveness resistance dial plate
Example 1 A A A B A A Example 2 A A D B A A Example 3 A A C B A A
Example 4 B A A B A B Example 5 A B A B A A Example 6 B C A B A B
Example 7 A B A B B A Example 8 A C A C B A Example 9 B B A B A B
Example 10 B A A B A B Example 11 A A A A A A Example 12 A A D A A
A Example 13 A A A B A A Example 14 B A A A A B Comparative E E E
-- A E Example 1 Comparative C C D C B C Example 2 Comparative C B
D B A C Example 3 Comparative C C D B A C Example 4 Comparative E A
E D D E Example 5
[0236] As apparent from Table 3, according to the invention, the
optical component had a high antireflection function and also had
excellent antifogging property and abrasion resistance. In
particular, an excellent effect as described above was obtained
with a simple structure. Further, the timepieces including the
optical component had high visibility of the dial plate and the
like, and the aesthetic appearance (aestheticity) of the timepiece
as a whole was excellent. In addition, according to the invention,
the optical component could be produced with high productivity. On
the other hand, in the case of Comparative Examples, satisfactory
results were not obtained.
[0237] When timepieces were produced in the same manner as in the
above respective Examples and Comparative Examples except that in
addition to the cover glass, also the rear lid was configured in
the same manner as described above, the same results as described
above were obtained, and in the timepieces to which the optical
component according to the invention was applied (timepieces
according to the invention), the aesthetic appearance
(aestheticity) could be made particularly excellent.
[0238] When cover glasses (optical components) and timepieces were
produced in the same manner as described above except that the
application of the antireflection film forming composition was
performed by a roll coating method or a spin coating method and the
evaluation was performed in the same manner as described above, the
same results as described above were obtained.
[0239] The entire disclosure of Japanese Patent Application No.
2014-244845, filed Dec. 3, 2014 is expressly incorporated by
reference herein.
* * * * *