U.S. patent application number 12/083728 was filed with the patent office on 2009-09-17 for removal method and removal apparatus for entrained air in coating fluid.
This patent application is currently assigned to Tokuyama Corporation. Invention is credited to Naoto Takahashi.
Application Number | 20090229465 12/083728 |
Document ID | / |
Family ID | 37962602 |
Filed Date | 2009-09-17 |
United States Patent
Application |
20090229465 |
Kind Code |
A1 |
Takahashi; Naoto |
September 17, 2009 |
Removal Method and Removal Apparatus for Entrained Air in Coating
Fluid
Abstract
The present invention has as an object to render a photochromic
coating layer free from air bubbles and obtain a uniform layer
without film thickness unevenness in the coating layer. In the
prevent invention, entrained air in a coating fluid stored in a
vessel of a coating unit comprising the vessel, a check valve for
preventing back-flow of the coating fluid connected to the vessel,
and optionally an ejection nozzle connected to the check valve; air
existing inside of the check valve; and optionally air existing
inside of the ejection nozzle are removed by plugging an outlet of
the coating fluid existing downstream of the check valve and then
rotating the coating unit on an axis of the vessel and orbiting the
coating unit on a revolution axis simultaneously.
Inventors: |
Takahashi; Naoto;
(Yamaguchi, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
Tokuyama Corporation
Shunan-shi, Yamaguchi
JP
|
Family ID: |
37962602 |
Appl. No.: |
12/083728 |
Filed: |
October 16, 2006 |
PCT Filed: |
October 16, 2006 |
PCT NO: |
PCT/JP2006/320979 |
371 Date: |
September 12, 2008 |
Current U.S.
Class: |
427/164 ; 95/261;
96/216 |
Current CPC
Class: |
B01D 19/0057 20130101;
B01D 19/0052 20130101; G02B 5/23 20130101; B01D 19/0063 20130101;
B05D 1/26 20130101 |
Class at
Publication: |
95/258 ; 95/262;
96/202; 96/203 |
International
Class: |
B01D 19/00 20060101
B01D019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 2005 |
JP |
2005-306169 |
Claims
1. A method for removing air from a coating fluid containing
entrained air comprising the steps of: (A) preparing a coating unit
comprising a cylindrical vessel storing the coating fluid and a
check valve for preventing back-flow of the coating fluid
connecting with the vessel; (B) plugging an outlet of the coating
fluid existing downstream of the check valve; and (C) rotating the
coating unit on an axis of the vessel and orbiting the coating unit
on a revolution axis simultaneously whereby introducing the coating
fluid into the check valve, discharging air resided inside of the
check valve toward the vessel, and further removing air
incorporated in the coating fluid from the coating fluid.
2. The method according to claim 1, wherein the coating unit
prepared in the step (A) further contains an ejection nozzle for
ejecting the coating fluid connecting with the check valve, the
plugging in the step (B) is carried out by plugging an outlet of
the ejection nozzle, and the coating fluid is introduced into the
check valve and the ejection nozzle, and the air inside the check
valve and the air inside the ejection nozzle are discharged toward
the vessel in the step (C).
3. The method according to claim 1, wherein a rotational speed of
revolution of the coating unit is set such that the speed in a late
stage of a rotating operation is rendered higher than the speed in
an early stage of the rotating operation.
4. The method according to claim 1, wherein the coating fluid is a
photochromic coating fluid to be coated on a surface of
spectacles.
5. A removal apparatus for entrained air in a coating fluid, the
apparatus comprises a casing which can rotate on a rotation axis
and also can orbit on revolution axis, and a coating unit
comprising a cylindrical vessel accommodating a coating fluid
inside, a check valve for preventing back-flow of the coating fluid
connecting the vessel and a lid for plugging an outlet of the
coating fluid existing downstream of the check valve; wherein the
rotation axis being located, with respect to the revolution axis,
outwardly and downwardly in a circumferential direction of an
orbital on the revolution axis, the coating unit being supported by
the casing detachably such that the lid of the coating unit is
located below, and the coating unit being rotated on the rotation
axis and being orbit on the revolution axis simultaneously with the
casing, to discharge air resided inside of the check valve toward
the vessel, and further to remove air incorporated in the coating
fluid.
6. The removal apparatus for entrained air in a coating fluid
according to claim 5, wherein the coating unit further contains an
ejection nozzle for ejecting the coating fluid connecting with the
check valve, and the lid is mounted on a tip portion of the
ejection nozzle.
7. The removal apparatus for entrained air in a coating fluid
according to claim 5, wherein the coating fluid is a photochromic
coating fluid to be coated on a surface of spectacles.
8. The removal apparatus for entrained air in a coating fluid
according to claim 5, wherein a flange facing outward is formed on
a periphery of the vessel, and the flange is detachably mounted on
the casing.
Description
TECHNICAL FIELD
[0001] This invention relates to a method for removing air
entrained in a coating fluid stored in a container called a coating
unit, and a removal apparatus for use in its removal.
BACKGROUND ART
[0002] Among materials which change in color when exposed to light
is a photochromic material. The photochromic substance has the
property that its structure reversibly changes according to the
presence or absence of ultraviolet radiation to change in
absorption spectrum. This property results from the nature that
when an isomer is irradiated with light of a particular wavelength,
the single chemical substance, under the action of light,
reversibly produces an isomer having a different absorption
spectrum. The resulting different isomer is restored to the color
of the original isomer by heat or light of a different
wavelength.
[0003] Photochromic spectacles utilize the above nature of the
photochromic material for lenses. In an outdoor environment exposed
to light including ultraviolet radiation, such as sunlight, the
lenses are rapidly colored to function as sunglasses. In an indoor
environment without exposure to light, the lenses fade to function
as ordinary transparent spectacles.
[0004] Known methods for producing a lens having photochromic
property include a method of impregnating the surface of a
non-photochromic lens with a photochromic coating fluid; a method
which comprises dissolving a photochromic coating fluid in a
monomer, and polymerizing the solution to obtain a photochromic
lens directly; and a method comprising providing a layer having
photochromic property on the surface of a lens with the use of a
coating agent containing a photochromic compound (namely, a coating
method). An apparatus for forming a layer having photochromic
property on a lens by the coating method is disclosed.
[0005] In the above-described coating method, when the photochromic
coating fluid is supplied onto the lens, the photochromic fluid is
ejected from the nozzle of a vessel containing the photochromic
fluid to the surface of the lens to form a coating layer on the
surface of the lens.
[0006] However, the photochromic fluid has viscosity, so that if
air is entrained in the fluid, air bubbles are formed in the
resulting coating layer. The nozzle of the vessel is provided with
a check valve for preventing fluid dripping. In this case, air may
be incorporated in the nozzle at the start of operation, thus
requiring that air in the nozzle be discharged outside before start
of the operation. For this purpose, air purge of the nozzle is
performed using the coating fluid. This poses the problem of a
great expenditure, because the photochromic fluid is expensive.
[0007] The present invention has been accomplished in the light of
such circumstances. It is an object of the invention to provide a
removal method for entrained air in a coating nozzle, and a coating
apparatus, the removal method and the coating apparatus unable to
form an uniform photochromic coating film without voids and
thickness unevenness.
[0008] In connection with the present invention, technologies such
as the technology described in Japanese Unexamined Patent
Publication No. 2000-334369 concerning with an apparatus which can
coat a plurality of lenses continuously, the technology described
in Japanese Unexamined Patent Publication No. 2005-013873
concerning with an apparatus equipped with an auxiliary mechanism
for spreading a coating fluid on a lens with the use of a flexible
film, and the technology described in Japanese Unexamined Patent
Publication No. 2005-218994 concerning with an apparatus which
adjusts the rotational state of a lens according to the shape of
the lens or the viscosity of a coating fluid are available.
DISCLOSURE OF THE INVENTION
[0009] The method for removing air from a coating fluid containing
entrained air according to the present invention (hereinafter
referred to as the removal method for entrained air according to
the present invention) comprising the steps of:
[0010] (A) preparing a coating unit comprising a cylindrical vessel
storing the coating fluid and a check valve for preventing
back-flow of the coating fluid connecting with the vessel;
[0011] (B) plugging an outlet of the coating fluid existing
downstream of the check valve; and
[0012] (C) rotating the coating unit on an axis of the vessel and
orbiting the coating unit on a revolution axis simultaneously
whereby introducing the coating fluid into the check valve,
discharging air resided inside of the check valve toward the
vessel, and further removing air incorporated in the coating fluid
from the coating fluid.
[0013] In the present invention described above, the coating unit
prepared in the step (A) further can contain an ejection nozzle for
ejecting the coating fluid connecting with the check valve. In such
a case, the plugging in the step (B) is carried out by plugging an
outlet of the ejection nozzle, and the coating fluid is introduced
into the check valve and the ejection nozzle, and the air inside
the check valve and the air inside the ejection nozzle are
discharged toward the vessel in the step (C). Meanwhile, the air
inside the ejection nozzle is not discharged when the deaeration
was carried out using the coating unit without the ejection nozzle
and the ejection nozzle was loaded after the deaeration.
[0014] In the present invention, the rotational speed of revolution
of the coating unit is preferably set such that the speed in the
late stage of a rotating operation is rendered higher than the
speed in the early stage of the rotating operation.
[0015] In the present invention, the coating fluid can be a
photochromic coating fluid to be coated on the surface of
spectacles.
[0016] The removal apparatus for entrained air in a coating fluid
according to the present invention (hereinafter referred to as the
removal apparatus for entrained air or deaeration apparatus of the
present invention) comprises a casing which can rotate on a
rotation axis and also can orbit on revolution axis, and a coating
unit comprising a cylindrical vessel accommodating a coating fluid
inside, a check valve for preventing back-flow of the coating fluid
connecting the vessel and a lid for plugging an outlet of the
coating fluid existing downstream of the check valve; wherein
[0017] the rotation axis being located, with respect to the
revolution axis, outwardly and downwardly in a circumferential
direction of an orbital on the revolution axis,
[0018] the coating unit being supported by the casing detachably
such that the lid of the coating unit is located below, and
[0019] the coating unit being rotated on the rotation axis and
being orbit on the revolution axis simultaneously with the casing,
to discharge air resided inside of the check valve toward the
vessel, and further to remove air incorporated in the coating
fluid.
[0020] The coating fluid used in the present invention can be a
photochromic coating fluid to be coated on the surface of
spectacles.
[0021] In the present invention, a flange facing outward can be
formed on the periphery of the vessel, and the flange can be
detachably mounted on the casing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a plan view of a photochromic coating apparatus
described in an embodiment of the present invention.
[0023] FIG. 2 is a front view of the photochromic coating apparatus
of FIG. 1.
[0024] FIG. 3 is a longitudinal (in the up-and-down direction; the
same applies hereinafter) sectional view of a lens support device
in the photochromic coating apparatus of FIG. 1.
[0025] FIG. 4 is a front view of a coating unit support device in
the photochromic coating apparatus of FIG. 1.
[0026] FIG. 5 is a side view of the coating unit support device of
FIG. 4.
[0027] FIG. 6 is a longitudinal sectional view of a coating unit
supported by the photochromic coating apparatus of FIG. 4.
[0028] FIG. 7A is a longitudinal sectional view, before deaeration,
of a fluid drip preventing valve (the check valve) mounted in the
vicinity of an outlet of the coating unit of FIG. 6. FIG. 7B is a
longitudinal sectional view, after deaeration, of the fluid drip
preventing valve.
[0029] FIG. 8 is a schematic view of a removal apparatus according
to the embodiment of the present invention.
[0030] FIG. 9 is a sectional view of a state in which the coating
unit of FIG. 6 is supported by the casing.
[0031] FIG. 10 is a plan view of a lens height measuring sensor in
the photochromic coating apparatus of FIG. 1.
[0032] FIG. 11 is a side view of the lens height measuring sensor
of FIG. 10.
[0033] FIG. 12 is a plan view of a coating film uniformizing device
in the photochromic coating apparatus of FIG. 1.
[0034] FIG. 13 is a plan view of the coating film uniformizing
device of FIG. 12.
[0035] FIG. 14 is a side view of a UV device in the photochromic
coating apparatus of FIG. 1.
[0036] FIG. 15 is an enlarged side view of the UV device of FIG.
14.
[0037] FIG. 16 is a plan view of a movable fluid receiving device
in the photochromic coating apparatus of FIG. 1.
[0038] FIG. 17 is a side view of the movable fluid receiving device
of FIG. 16.
[0039] FIG. 18 is a flowchart of the coating apparatus for a
lens.
[0040] FIG. 19A is a sectional view of a state in which the height
of the lens is measured with laser light from the lens height
measuring sensor shown in FIG. 10. FIG. 19B is a sectional view for
illustrating how to lead to the edge position of the lens.
BEST MODE FOR CARRYING OUT THE INVENTION
[0041] An embodiment of a removal method for entrained air in a
coating fluid according to the present invention will now be
described with reference to the accompanying drawings.
[0042] FIGS. 1 and 2 show a photochromic coating apparatus for
coating a photochromic fluid onto a lens under automatic control.
The lower side of the photochromic coating apparatus in FIG. 1 is
the front side of the apparatus (in the Y-axis direction), and the
right-to-left side of the apparatus is in the lateral direction
(X-axis direction).
[0043] A photochromic coating apparatus 1 has a lens support device
3, a coating unit support device 4, a lens height measuring sensor
6, a coating film uniformizing device 7, a UV device 8, and a
movable fluid receiving device 9 provided on a base stand 2.
[0044] As shown in FIG. 3, the lens support device 3 is provided in
a nearly central portion of the base stand 2, and has a circular
pedestal 31 formed to protrude upward from the base stand 2. A
guide member 32 is provided inwardly of the base stand 2, and a
Z-axis ball screw 33 having an axis pointing in the up-and-down
(vertical) direction is provided on the guide member 32. The Z-axis
ball screw 33 has an upper end portion rotatably mounted on the
guide member 32, and a lower end portion mounted on a servo motor
34. A Z-axis ball nut 36 mounted on a lens support member 35 is
screwed to the Z-axis ball screw 33. As the Z-axis ball screw 33 is
rotated, the lens support member 35 can move upward and downward
along the Z-axis ball screw 33. A servo motor 37 is fixed to a
lower portion of the lens support member 35, and a rotating shaft
38 extending upward is mounted on the servo motor 37. The rotating
shaft 38 passes through a hole 31a formed in the circular pedestal,
and a lens support stand 39 is mounted on a front end portion of
the rotating shaft 38. When the servo motor 37 is rotated, the lens
support stand 39 rotates about the rotating shaft 38.
[0045] FIGS. 4 and 5 show the coating unit support device 4. In the
coating unit support device 4, an air slide table 11 is provided on
the base stand 2, and a slide block 12 is fitted onto the slide
table 11 to be slidable in the lateral direction of the
photochromic coating apparatus 1. The slide block 12 is slidable by
a rodless cylinder, and the rodless cylinder of the air type, chain
type, magnet type, slit type, or wire type can be applied (the same
is true of rodless cylinders to follow).
[0046] A support arm 13 extending toward the front side of the base
stand 2 is mounted on an upper end portion of the slide block 12
erected upward, and a coating unit 21 is supported by the support
arm 13. The support arm 13 is mounted such that the support angle
of the coating unit 21 can be changed about a pivot shaft 14 as an
axis. That is, as shown in FIG. 4, the support arm 13 can support
the coating unit 21 in an upright posture, or in an inclined state
as indicated by imaginary lines. The coating unit 21 can be moved
to directly above the center of a lens 10 by the lateral slide of
the slide block 12 on the air slide table 11.
[0047] As shown in FIG. 6, the coating unit 21 is equipped with a
vessel 22, a check valve (a fluid drip preventing valve) 23, and a
nozzle 24. A coating fluid is contained in the vessel 22, the upper
end of the check valve 23 is detachably connected to a lower
portion of the vessel 22, and the nozzle 24 is detachably connected
to the lower end of the check valve 23.
[0048] As shown in FIGS. 7A, 7B, the check valve 23 has a first
small-diameter portion 23a on its upper end side connected to the
vessel 22, a large-diameter portion 23b at its center, and a second
small-diameter portion 23c at the leading end side thereof. A valve
seat 23d, where a cushioning material 23e such as an O-ring is
disposed, is formed at the boundary between the first
small-diameter portion 23a and the large-diameter portion 23b. A
valve ball 25 of a spherical shape is disposed in the
large-diameter portion 23b, and a spring 26 is disposed in a
compressed state between the valve ball 25 and the second
small-diameter portion 23c.
[0049] A plunger 27 is disposed inside the vessel 22, and when a
compression source (N2) connected to piping 22b imposes a load, the
plunger 27 presses the coating fluid to open the valve composed of
the valve seat 23d and the valve ball 25. In this manner, the valve
ball 25 is urged against the valve seat 23d by the spring 26 to
restrain the flow of the coating fluid from the nozzle 24 toward
the vessel 22. On the other hand, when the valve ball 25 is pressed
in opposition to the force of the spring 26, the flow of the
coating fluid from the vessel 22 toward the nozzle 24 is
allowed.
[0050] An explanation will be offered for a removal apparatus 15
according to the present invention for removing air (air bubbles)
contained in the coating fluid accommodated in the coating unit
21.
[0051] The removal apparatus 15 shown in FIG. 8 is provided
separately from the photochromic coating apparatus 1. Before the
coating unit 21 is set in the coating unit support device 4,
deaeration treatment is performed by the removal apparatus 15. The
removal apparatus 15 is provided with a rotating body 16, and the
rotating body 16 can be rotated on an axis of rotation (a
revolution axis) 17. A casing 28 for supporting the coating unit
21, as shown in FIG. 9, is arranged at a position remote from the
center of the rotating body 16. A hole 28a is formed in a central
portion of the casing 28, and the coating unit 21 can be detachably
mounted in the hole 28a. An annular boss portion 28b is formed on
the upper surface of the casing 28 above the hole 28a, and a rubber
packing 22a is mounted on the boss portion 28b by screws 29. The
rubber packing 22a is mounted to suppress the freewheeling of the
vessel 22 of the coating unit 21 by making contact with the
periphery of the vessel 22 when the coating unit 21 is rotated by
the removal apparatus 15. An O-ring 30 as a cushioning material is
disposed at the bottom of the hole 28a into which the coating unit
21 is inserted.
[0052] The coating unit 21 has an axis (a rotation axis) 18
inclined in the up-and-down direction within the casing 28. A lower
portion of the coating unit 21 is directed toward the outer
periphery of the rotating body 16, while an upper portion of the
coating unit 21 is directed toward the upper side of the axis of
rotation (the revolution axis) 17 of the rotating body 16. The
ejection nozzle 24 is provided at a leading end portion of the
coating unit 21, and a lid 24a is mounted on the outlet of the
ejection nozzle 24.
[0053] The casing 28 is adapted to be rotated by a drive motor 19
on the axis (the rotation axis) 18 together with the coating unit
21. The rotating body 16 is arranged to be rotated or orbited by a
drive motor 20 on the axis of rotation (the revolution axis) 17.
The coating unit 21 can do orbital motion or revolution which means
orbiting on a revolution axis on the revolution axis 17, and can
rotate on the rotation axis 18 which corresponding with an axis of
the vessel 22.
[0054] FIGS. 10 and 11 show the lens height measuring sensor 6.
[0055] The lens height measuring sensor 6 is provided with a slide
plate 40 serving as a base stand. The slide plate 40 is disposed
such that its leading end side faces toward the lens support member
35, its rear end side faces toward a corner portion of the
photochromic coating apparatus 1, and the slide plate 40 is
provided nearly on diagonals of the photochromic coating apparatus
1 of a generally rectangular shape. A slide block 41, which can
move back and forth on the slide plate 40, is provided on top of
the slide plate 40. A sensor-mounting member 42 of a U-shape is
provided on the slide block 41, and two sensors 43 and 44 are
disposed in opposite side end portions of the sensor-mounting
member 42 which confront each other. The sensor units 43, 44 have
sensors 43a, 44a each having a light emitting portion and a light
receiving portion. The light emitting portion emits laser light,
mirrors 43b, 44b reflect the laser light, and the sensors 43a, 44a
can detect the reflected laser light.
[0056] The sensor units 43, 44 comprise the sensors 43a, 44a and
the mirrors 43b, 44b disposed to be staggered and opposed. A line
connecting one sensor 43a and one mirror 43b, and a line connecting
the other sensor 44a and the other mirror 44b are arranged at the
same horizontal height position and in parallel. The lens 10 is
placed between the sensors 43a, 44a and the mirrors 43b, 44b. The
sensor units 43, 44 detect the presence of the lens 10 such that
when the lens 10 is placed between the sensors 43a, 44a and the
mirrors 43b, 44b, light is crooked by the lens 10 and thereby
blocked.
[0057] FIGS. 12 and 13 show the coating film uniformizing device
7.
[0058] The coating film uniformizing device 7 has a linear block 50
provided on the base stand 2. In the linear block 50, a linear rail
51 extends in the lateral direction of the photochromic coating
apparatus 1. An X-axis servo motor 52 is mounted on one end side of
the linear block 50, and an X-axis ball screw 53 journaled by
bearings 54a, 54b is rotatably mounted on the X-axis servo motor
52. An X-axis ball nut 55 is screwed to the X-axis ball screw 53,
and as the servo motor 52 is rotated, the X-axis ball nut 55 can be
moved laterally. A longitudinal linear block 56 erected upward is
mounted on the X-axis ball nut 55.
[0059] A servo motor 57 is mounted on an upper portion of the
longitudinal linear block 56, and a Z-axis ball nut 60 is screwed
to a Z-axis ball screw 59 journaled by bearings 58a and 58b. An
elevating stage 61 is mounted on the Z-axis ball nut 60. When the
servo motor 57 rotates, the elevating stage 61 can move up and
down. An arm 62 extending toward the lens support member 35 is
provided on the elevating stage 61, and a support bracket 63 is
provided at a leading end portion of the arm 62. A flexible film
64, which is made of resin such as PET and aims to uniformize the
thickness of a film of the photochromic coating fluid, is suspended
from the support bracket 63. When the elevating stage 61 is moved
in the lateral direction by driving the X-axis servo motor 52, the
film 64 travels in a radial trajectory on the center of the lens
10.
[0060] FIG. 14 shows the UV device 8.
[0061] The UV device 8 has a main block 70 which can be raised and
lowered in the up-and-down direction by an elevating means (not
shown). A UV elevating unit 71 is provided in the main block 70,
and a servo motor 72 is mounted on the UV elevating unit 71. A
Z-axis ball nut 75 is screwed to a Z-axis ball screw 74 journaled
by bearings 73a and 73b. A UV elevating stage 76 is mounted on the
Z-axis ball nut 75. The UV elevating stage 76 moves up and down in
accordance with the rotation of the servo motor 72. A UV light 77
to be disposed directly above the lens 10 is provided on the UV
elevating stage 76.
[0062] A cylinder 78 surrounding the lens 10 and comprising
stainless steel is provided below the UV light 77. A cooling pipe
79 wound in a coil is disposed on the periphery of the cylinder 78,
and cooling water can circulate inside the cooling pipe 79. As
shown in FIG. 15, gas supply ports 80 are provided in an upper
portion of the cylinder 78 to be capable of introducing N.sub.2, an
inert gas, into the cylinder 78, and N.sub.2 is discharged to the
outside of the cylinder 78 through gas discharge ports 81 provided
in a lower portion of the cylinder 78. A window 78a formed from
borosilicate glass for transmission of UV light is provided in an
upper portion of the cylinder 78, as shown in FIG. 15.
[0063] FIGS. 16 and 17 show the movable fluid receiving device
9.
[0064] The movable fluid receiving device 9 has a pair of guide
rails 83 provided on the back of the base stand 2, and a pair of
movable units 84 provided at both ends of the lens support device 3
move back and forth, with the lens support device 3 being
positioned therebetween. A pair of semicircular fluid receiving
portions 85 are provided at an upper portion of the movable units
84. When the pair of fluid receiving portions 85 move forward, they
are formed in an annular tubular shape to accept the coating fluid,
which falls from the lens 10, between an outer tubular portion 86
and an inner tubular portion 87. The inner tubular portion 87 has
an upper edge portion 85a disposed below the outer periphery of the
lens 10.
[0065] A installing jig 88 for a temperature sensor, and a spatula
fixing jig 89 for preventing the adhesion of the coating fluid onto
the side surface of the lens 10 are provided at the outer tubular
portion 86. The numeral 90 denotes a baffle plate for blocking a
clearance at the junction between the fluid receiving portions
85.
[0066] The procedure for photochromic coating of the lens according
to the present embodiment will be described below.
[0067] FIG. 18 is a flowchart showing a manufacturing process for a
photochromic spectacle lens.
[0068] A lens base material prepared from thiourethane resin is
used as a base material, and cleaning of the lens 10 with an
aqueous solution of an alkali or by ultrasonic cleaning is
performed as pretreatment.
[0069] Then, before coating with the photochromic material, the
surface of the lens 10 is coated with a urethane primer to improve
the adhesion of the photochromic material. This operation is
performed by linearly moving the nozzle, which ejects the coating
fluid (the urethane primer), in the radial direction of the lens
from the center of the upper surface of the lens to the edge of the
upper surface of the lens while rotating the lens 10. Since the
coating fluid (the urethane primer) has low viscosity, the coating
fluid can be spread equally on the entire surface of the lens 10 by
the centrifugal force of the rotated lens 10. Concretely, the
rotational speed of the lens 10 during coating with the coating
fluid (the urethane primer) is about 70 rpm. After coating with the
coating fluid (the urethane primer), the lens 10 is rotated for 5
seconds or so at 1,000 rpm to adjust the film thickness. The
thickness of the coating layer is, for example, 7 .mu.m. These
rotational speeds are varied according to the gradient of the lens
10 and the temperature around the lens 10, thereby adjusting the
film thickness to an appropriate film thickness.
[0070] After the coating layer (the primer layer) is applied, the
coating layer (the primer layer) is dried (solidified) for 15
minutes at room temperature. The coating layer comprising the
urethane primer has the property of becoming solid when exposed to
moisture. The operation performed up to this stage constitutes a
primer coating step.
[0071] Then, the lens is subjected to a photochromic coating step.
In this coating operation, as shown in FIG. 3, the lens 10 is set
at the center of the lens support member 35 of the photochromic
coating apparatus 1. Positioning of the lens 10 is performed by a
centering device (not shown). After the lens 10 is positioned in
the planar direction, the height position of the lens 10 and the
edge (peripheral edge on the upper surface side of the lens)
position of the lens 10 are determined by the lens height measuring
sensor 6, as shown in FIGS. 10 and 11.
[0072] Determination of the height position is performed, with the
lens 10 being held between the sensors 43a, 44a and the mirrors
43b, 44b of the sensor units 43, 44. When the lens support member
35 is raised from a lower position, laser light 43c from one sensor
43a located at the center position of the lens 10 is refracted by
the lens 10. Thus, the laser light 43c does not reach the sensor
43a, so that the presence of the lens 10 is detected. In this
state, laser light 44c from the sensor 44a of the other sensor unit
44 is reflected by the mirror 43b and reaches the sensor 44a, thus
showing the absence of the lens 10. When the lens 10 is further
raised, the laser light 44c hits the lens 10, and the laser light
44c emitted from the sensor 44a is blocked because of refraction of
the laser light 44c. Thus, the presence of the lens 10 is
recognized. In this manner, the center position (vertex) of the
lens 10 and the height of an arbitrary position of the lens 10
other than the center are detected.
[0073] The position of the edge, which is the marginal portion of
the lens 10, can be found by knowing the height position of the
center of the lens 10, and detecting the gradient in the radial
direction of the lens 10 (the height of the lens surface) by the
other sensor unit 44. That is, a knowledge of the distance between
two points enables the edge position to be calculated from the
approximation expression h'=H.sub.0D.sup.2/4L.sup.2 (h': the height
of the lens, h.sub.0: the measured value of the height of the lens,
D: the diameter of the lens, L: the distance between the sensors,
normally 27 mm) with reference to FIG. 19B. The shape of the lens
is circular or nearly circular before cutting of the lens, so that
the diameter D of the lens can be found without problem. In this
manner, the height of the lens 43 is adjusted to an appropriate
height directly below the discharge orifice of the nozzle 24 of the
coating unit 21.
[0074] After the lens 10 is positioned and its gradient is
detected, a coating operation for the photochromic fluid is
performed. As pretreatment for the coating operation, deaeration
treatment of the coating unit 21 is carried out as shown in FIG. 8.
That is, the drive motors 19 and 20 are driven, whereby the coating
unit 21 is rotated about the axis of rotation 17 of the deaeration
device 15 while being rotated about its own inclined axis 18. In
preferred embodiments, the radius of rotation of the coating unit
21 about the axis of rotation 17 is 100 to 200 mm, and the
rotational speed of this rotation is 600 to 2,000 rpm, whereas the
rotational speed of the rotation of the coating unit 21 about its
own axis 18 is 0 to 300 rpm.
[0075] Because of the rotation by such deaeration treatment, the
coating fluid within the vessel 22 presses the valve ball 25 in
opposition to the pressing force of the spring 26. As a result, the
coating fluid enters the check valve 23, while air within the check
valve 23 flows into the vessel 22.
[0076] It should be noted in the present invention that the
deaeration treatment is performed, with the vessel 22 being mounted
with the check valve 23. By so doing, the check valve 23, which has
not been charged with the coating fluid, can be charged with the
coating fluid free of air bubbles. In the check valve 23 already
containing the coating fluid, the spring 26 is disposed in the
check valve 23, and thus air is apt to enter between the twists of
its coil. Since this air can be removed, great advantages are
obtained. That is, the amount of the expensive photochromic fluid
for air purge can be decreased, and deaeration can be reliably
completed in a short time. In the coating operation, the lid 23a is
detached from the check valve 23, and the ejection nozzle 24 is
connected. Since the ejection nozzle 24 has not been deaerated, it
is air-purged. However, its amount air-purged may be small, because
its capacity is small. Furthermore, with the ejection nozzle 24
being connected to the check valve 23, the ejection nozzle 24 may
be lidded, and deaerated. Air purge can be done in a small amount,
or can be omitted.
[0077] There is a case where stirring and deaeration are performed
for the coating fluid whose constituents have not been thoroughly
uniformized. In this case, depending on the properties of the
coating fluid, the coating fluid, which has not been fully stirred
or uniformized, flows from the vessel 22 into the check valve 23 or
the ejection nozzle 24, and is stirred and deaerated at respective
sites. As a result, the composition of the coating fluid may be
different at various sites in the interior of the vessel 22, the
check valve 23, and the ejection nozzle 24. As a method of
preventing this difference, the rotational speed of the drive motor
20 is decreased to reduce the revolution or the orbital motion of
the vessel 22 on the revolution axis 17. With this state kept
during the drive motor 19 is rotated to uniform the coating fluid,
it can be possible to suppress the inflow of the nonuniform coating
fluid into the check valve 23. After the coating fluid in the
vessel 22 is sufficiently stirred, the rotational speed of the
drive motor 20 is increased to flow the coating fluid into the
check valve 23, whereby deaeration treatment can be performed.
Alternatively, the coating fluid may be thoroughly stirred in a
different container by other ordinary stirring means such as a
planetary stirring deaeration device or an agitating blade,
whereafter the coating fluid may be transferred into the vessel 22,
and deaerated by the removal apparatus 15 of the present invention,
although this procedure requires many steps.
[0078] By so rotating the rotating body 16 and the coating unit 21,
the coating unit 21 makes revolution on the revolution axis 17 and
rotation on the rotation axis 18 at the same time, thereby
performing stirring and deaeration of the coating fluid within the
coating unit 21. Further, the photochromic coating fluid having
high viscosity can be uniformized.
[0079] The coating unit 21, which has finished deaeration
treatment, is supported by the coating unit support device 4 shown
in FIGS. 4 and 5, and the nozzle 24 of the coating unit 21 is
disposed directly above the lens 10. The lens 10 is supported on
the lens support member 35 while being rotated (about 100 rpm). In
the coating unit 21, the vessel 22 is tilted to fix the nozzle 24
at the central position of the lens 10. The plunger 27 of the
coating unit 21 presses the coating fluid to open the check valve
23, thereby ejecting the coating fluid onto the surface of the lens
10 through the nozzle 24. In this ejection operation, as indicated
by imaginary lines in FIG. 4, the coating unit 21 is inclined to
set the tip of the nozzle 24 at the central position of the lens 10
(a position on the axis of rotation of the lens 10 and about 1 mm
above the surface of the lens 10). In this state, the coating fluid
is ejected onto the surface of the lens 10.
[0080] Simultaneously, the film 64 of the coating film uniformizing
device 7 is moved and pressed against the lens surface. In this
state, the film 64 is moved in a linear trajectory from the center
of the lens 10 to the edge of the lens 10. This is because the
photochromic coating fluid has great viscosity and does not spread
under centrifugal force due to the rotation of the lens 10. Thus,
the coating fluid is spread to the entire surface of the lens 10 by
the rotational force of the lens 10 and the linear movement of the
film 64. The reason why the nozzle 24 is inclined is that
interference between the film 64 and the nozzle 24 is prevented by
the inclination. The nozzle 24 may have the tip bent in an L-shape
to avoid interference with the film 64. As described earlier, the
coating unit is rotated beforehand on the revolution axis 17 and is
rotated on the rotation axis 18 to carry out deaeration. Thus, no
air bubbles are contained in the coating fluid, and the whole of
the coating fluid is rendered uniform, so that a uniform coating
film free from air bubbles and film thickness irregularities can be
obtained.
[0081] At this stage, the amount of the photochromic coating fluid
on the lens 10 is larger than the film thickness of the desired
photochromic film, thus making it necessary to remove the surplus
coating fluid on the lens 10 until the desired amount of the fluid
is attained. Thus, an operation for rotating the lens 10 to spin
off the coating fluid on the lens 10 is performed. The rotational
speed of the lens 10 is determined by conditions conformed to the
temperature inside the apparatus and the gradient of the lens 10.
For example, the lens 10 is spun at 600 rpm.
[0082] Then, the lens 10 is surrounded by the cylinder 78 of the UV
device 78, and the interior of the cylinder 10 is purged with
nitrogen. The reason for providing a nitrogen atmosphere is that in
the presence of oxygen, the coating film minimally cures. The UV
lamp 77 is brought to an appropriate height position, and the
coating film is cured by the UV lamp 77. The window 78a installed
between the UV lamp 77 and the lens 10 allows UV light to be
transmitted into the cylinder 78, and also plays the role of a
filter for screening out light of a wavelength in the vicinity of
300 nm or shorter.
[0083] The reason for cutting off the wavelength in the vicinity of
300 nm or shorter is that depending on the type of the photochromic
coating fluid, the coating film is wrinkled, and a uniform film is
not obtained. The reason why borosilicate glass is used as the
material is that this material is heat-resistant and does not break
under heat of the UV lamp.
[0084] After completion of photochromic coating, the photochromic
coating layer is inspected for the state of adhesion. The coating
layer poorly adhered is rejected, and a good product is subjected
to annealing treatment. This treatment is heat treatment performed
for 1 hour at 110.degree. C.
[0085] In this manner, the photochromic coating layer is formed on
the lens 10. This coating layer is the one obtained after air is
removed by the removal apparatus 15, and the coating fluid is
deaerated and stirred not only in the vessel 22, but also in the
check valve 23 (or, also including the ejection nozzle 24). Thus,
the coating unit 21 as a whole ensures coating with a uniform
coating fluid free from concentration unevenness. Consequently, a
high quality photochromic lens can be produced.
[0086] The embodiment of the present invention has been described
above, but needless to say, various modifications or changes of the
present invention are possible based on the technical ideas of the
present invention.
[0087] For example, in connection with the sensor units 43, 44, the
line connecting the sensor 43a and the mirror 43b is located at the
same horizontal height position as the line connecting the other
sensor 44a and the other mirror 44b, but one of the sensors may be
located at a different height position to provide a height
difference between the two sensors. In this case, the edge position
of the lens 10 is determined in consideration of the height
difference between the sensors.
[0088] According to the embodiment of the present invention,
photochromic coating is taken as an example. However, the present
invention can be applied to other coating technologies.
[0089] The spectacle lens having a convex surface and a concave
surface has been coated, but the present invention can be applied
to coating of glass having flat surfaces.
[0090] The removal method for entrained air according to the
present invention comprising the steps of:
[0091] (A) preparing a coating unit comprising a cylindrical vessel
storing the coating fluid and a check valve for preventing
back-flow of the coating fluid connecting with the vessel;
[0092] (B) plugging an outlet of the coating fluid existing
downstream of the check valve; and
[0093] (C) rotating the coating unit on an axis of the vessel and
orbiting the coating unit on a revolution axis simultaneously
whereby introducing the coating fluid into the check valve,
discharging air inside the check valve toward the vessel, and
further removing air incorporated in the coating fluid from the
coating fluid. By thus removing air incorporated in the check
valve, air bubbles are not contained in the coating layer, and a
uniform layer free from film thickness unevenness can be obtained.
Nor is it necessary to perform air purge with the coating fluid, as
done conventionally, so that a saving in the coating fluid can be
made. The use of the check valve makes it possible to prevent fluid
drip of the coating fluid, and form a stable coating film.
[0094] In the above removal method for entrained air, the coating
unit prepared in the step (A) can further contain an ejection
nozzle for ejecting the coating fluid connecting with the check
valve and the plugging in the step (B) can be carried out by
plugging an outlet of the ejection nozzle. Thus, entrained air in
the ejection nozzle can also be removed, and a more stable coating
film can be formed.
[0095] In the above removal method for entrained air wherein a
rotational speed of revolution of the coating unit is set such that
the speed in a late stage of a rotating operation is rendered
higher than the speed in an early stage of the rotating operation,
if stirring of the respective components of the coating fluid is
not sufficient, or if the properties of the coating fluid render
stirring difficult, the coating fluid can be stirred sufficiently,
and the coating fluid can be uniformized.
[0096] Further, the coating fluid used in the above invention is a
photochromic coating fluid to be coated on the surface of
spectacles. Thus, a photochromic coating film of good quality can
be formed on the surface of spectacles.
[0097] The removal apparatus for entrained air according to the
present invention comprises a casing which can rotate on a rotation
axis and also can orbit on revolution axis, and a coating unit
comprising a cylindrical vessel accommodating a coating fluid
inside, a check valve for preventing back-flow of the coating fluid
connecting the vessel and a lid for plugging an outlet of the
coating fluid existing downstream of the check valve; wherein the
rotation axis being located, with respect to the revolution axis,
outwardly and downwardly in a circumferential direction of an
orbital on the revolution axis, the coating unit being supported by
the casing detachably such that the lid of the coating unit is
located below, and the coating unit being rotated on the rotation
axis and being orbit on the revolution axis simultaneously with the
casing, to deaerate air contained in the coating fluid. Thus, air
bubbles are not contained in the coating layer, and a uniform layer
free from film thickness unevenness can be obtained by using the
apparatus. Nor is it necessary to perform air purge with the
coating fluid, as done conventionally, so that a saving in the
coating fluid can be made.
[0098] When the lid on the check valve is detached, the ejection
nozzle is connected to the check valve, and then a lid is mounted
on a tip portion of the ejection nozzle, it is possible to remove
entrained air in the ejection nozzle and to form a more stable
coating film.
[0099] In the removal apparatus for entrained air according to the
present invention, the coating fluid is a photochromic coating
fluid to be coated on the surface of spectacles. Thus, a
photochromic coating film of good quality can be formed on the
surface of spectacles.
[0100] In the removal apparatus for entrained air, the flange
facing outward is formed on the vessel, and the flange is
detachably mounted on the casing. Thus, the vessel can be fixed
easily and reliably, and the vessel can be rotated stably.
* * * * *