TITLE: Lens forming system.
European Patent Application EP0318164 A2

ABSTRACT:
An apparatus and method for making spectacle lenses, and lenses which
can be produced thereby with particular front and back coatings. The
apparatus provides a clean, efficient, and relatively automated means
by which the lenses can be cast from a polymer and provided with
suitable front and/or back abrasion resistant coatings, if desired. The
apparatus includes means (12) for storing mold elements (28), means for
advancing identified mold elements (28) to a mold delivery station (14)
means (16) for storing gaskets (30), means for inserting an identified
pair of mold elements (28) into a selected gasket (30), alignment means
(22) and means for filling (24) and curing (26) the liquid polymeric
material to form the finished spectacle lens having specified opthalmic
lens prescription.

INVENTORS:
Kachel, Theodore V.
Rydeen, Clarence F.
Millar, Robert W.
Szuberla, Casimar
Dawson, Ralph C.
Griffith, Robert L.
Weitzel, William H.
Congleton, James T.
Benz, John A.
Duncan, Calvin P.

APPLICATION NUMBER: EP19880310232
PUBLICATION DATE: 05/31/1989
FILING DATE: 10/31/1988

ASSIGNEE: TECHNA VISION INC (US)
INTERNATIONAL CLASSES: B29C31/00; B29C33/00; B29C33/30; B29C39/02; B29C39/24; B29D11/00;
(IPC1-7): B29C31/00; B29D11/00; G02C7/02
EUROPEAN CLASSES: B29C31/00M; B29C33/00E; B29C33/30; B29C39/02; B29C39/24; B29D11/00C21

DOMESTIC PATENT REFERENCES:
EP0028975 Apparatus for making a composite glass, especially an
 ophthalmic lens.
EP0102847 Method for coating ophthalmic devices.
EP0107104 A process for fabricating thermoset resin articles.
EP0183324 Plant for the automatic production of organic lenses.

FOREIGN REFERENCES:
GB2124967A
DE3430690A1
DE2734416A1
GB1347762A
4441795  Molded multifocal lens and mold assembly
GB848669A
4347302  Process for applying a thin coating in liquid form and
subsequently drying it
NL106522C
GB1099566A
GB575923A
4447468  Photographic film coating apparatus and method
NL8400481A
3810403  CONTACT LENS EDGING MACHINE
3977358  Can feeding and coating apparatus
4476162  Method for coating lenses
DE3428645A1
FR2423521A
4490495  Composition and method for tinting plastic
4355135  Tintable abrasion resistant coatings
4211823  Tintable coatings and articles having such coatings
4401718  Process for applying a second silicone resin coating
composition over a first silicone resin coating composition

OTHER REFERENCES:
PATENT ABSTRACTS OF JAPAN, Vol. 7, No. 283 (M-263)(1428), December 16,
1983; & JP-A-58 158 230 (NITSUSEI JIYUSHI KOGYO K.K.) 20-09-1983,
Abstract.
PATENT ABSTRACTS OF JAPAN, Vol. 7, No. 254 (M-255)(1399), November 11,
1983; & JP-A-58 138 613 (MITSUBISHI DENKI K.K.) 17-08-1983, Abstract.

CLAIMS:
1. An apparatus for casting a finished spectacle lens of a specified
ophthalmic lens prescription, including means for storing a plurality
of mold elements to enable said apparatus to fill a variety of
different ophthalmic lens prescriptions, including means for advancing
identified mold elements to a mold delivery station, means for storing
a plurality of gaskets to enable said apparatus to fill different lens
prescriptions, each gasket being adapted to hold in a predetermined
spaced apart relationship a pair of mold elements inserted into a
selected gasket, means for inserting an identified pair of mold
elements into a selected gasket to form an assembly of gasket and mold
elements, alignment means for holding said selected gasket in a
reference position and for orienting the selected mold elements with
respect to each other in said selected gasket, and means for filling
the assembly of said selected gasket and said identified mold elements
with a liquid polymeric material that fills the space between said mold
elements and hardens on curing to form the finished spectacle lens
having said specified ophthalmic lens prescription.
2. The apparatus of claim 1 wherein the gasket or mold has thereon a
machine readable identification number.
3. The apparatus of claim 1 including oven means into which said
assembly with the polymeric material therein is placed for a
predetermined time period, said oven means including heat control means
for varying the temperature within said oven in accordance with a
predetermined program.
4. The apparatus of claim 1 including a station where the identified
mold elements are coated with a release agent prior to said identified
mold elements being inserted into the selected gasket.
5. An apparatus for casting a finished spectacle lens of a specified
ophthalmic prescription, including means for storing a plurality of
mold elements, each mold element bearing a machine readable marking
thereon identifying and distinguishing it from other mold elements,
said mold storing means having individual, movable mold containers for
each mold element, which are advanced to or withdrawn from a mold
delivery station, means for assembling a pair of mold elements
delivered to said mold delivery station in a gasket in a spaced apart
relationship to enable the space between said mold gaskets to be filled
with a liquid polymeric material that on curing hardens to form a lens,
means for reading the marking on a mold element and providing an
electronic control signal identifying the individual mold container
which holds said mold element, and control means responsive to said
control signal for advancing said individual mold container to the mold
delivery station.
6. A apparatus for casting a finished spectacle lens having a specified
ophthalmic prescription including means for storing a plurality of mold
elements and advancing individual mold elements to a mold delivery
station, gasket storage means for holding a plurality of different size
gaskets, each gasket bearing a machine readable marking thereon
providing an identification symbol thereon, input means for identifying
a pair of mold elements and gasket of a selected size to fill said
specified ophthalmic prescription, said input means including control
means for advancing the identified pair of molds to the mold delivery
station, means for assembling said identified pair of mold elements
delivered to said mold delivery station and said identified gasket into
an assemblage with the mold elements oriented relative to each other
and spaced apart to make a lens which fills said prescription, means
for filling the space between said mold elements with a liquid
polymeric material that hardens on curing, and means for reading the
marking on the gasket to confirm that the correct gasket has been
selected.
7. The apparatus of claim 6 including printout means that provide a tag
to be placed on the lens made by said apparatus identifying said lens
with the same marking as appears on the selected gasket or mold used to
make said lens.
8. The apparatus of claim 6 where a tag having a machine readable
marking is placed on the finished lens for identification.
9. An apparatus for casting a finished spectacle lens having a
specified ophthalmic prescription, including means for storing a
plurality of mold elements and advancing individual mold elements to a
mold delivery station, gasket storage means for holding a plurality of
different size gaskets input means for identifying a pair of mold
elements and gasket of a selected size to fill said specified
ophthalmic prescription, said input means including control means for
advancing the identified pair of molds to the mold delivery station,
means for assembling said identified pair of mold elements delivered to
said mold delivery station and said identified gasket in an assembly
with the mold elements oriented relative to each other and spaced apart
to make a lens which fills said prescription, means for storing in a
relatively cool chamber a plurality of different types of polymeric
materials used in casting lenses, and means for filling the space
between said molds with a selcted one of said different types of
polymeric materials.
10. In an apparatus for making spectacle lenses wherein resin is
introduced into a space between a pair of mold elements through a
passageway in a gasket holding said elements in a spaced apart
relationship, including: means for storing resin in a container, said
container having an outlet through which resin will flow when pressure
is applied to said resin, a dispensing head including a nozzle element
adapted to fit into the passageway in the gasket, said nozzle element
being in communication with the outlet in the container, and means for
inserting said nozzle into the passageway and applying pressure to the
resin to force resin through the outlet and nozzle into said space
between said mold elements.
11. In an apparatus for making spectacle lenses wherein resin is
introduced into a space between a pair of mold elements held in a
spaced apart relationship in a gasket, said gasket having two separate
ports each including a passageway leading to the space between said
mold elements, including: means for storing the resin in a plurality of
individual containers, each container holding a different color of
resin and container having an outlet through which the resin will flow
when a pressure is applied to said resin, a dispensing head including a
plurality of nozzle elements, each nozzle element being adapted to fit
into one of the fill ports and each nozzle element being in
communication with an outlet of one of the containers, means for
inserting one of the nozzle elements into one of the fill ports to
correspond with the prescribed color of the lens being made, means for
applying pressure to the selected resin to force this resin through the
outlet of its container through the nozzle inserted into the selected
fill port, and means for applying a vacuum to the other fill port so
that gas in the space between the mold elements is removed from said
space as resin flows into this space.
12. The apparatus of claim 16 wherein the resin is maintained in
storage means which are at a substantially lower temperature than
ambient.
13. A cannister for holding a resin material used in apparatus for
manufacturing spectacle lenses, comprising: a tubular body member
having a port adjacent one end of the body member and a plunger element
movable within the body member under applied pressure to push resin
from the body member out said port, said plunger element carrying a
member which activates a sensor near said end to indicate that the
resin is essentially depleted.
14. The cannister of claim 13 carrying tag means bearing a machine
readable code which indicates that the resin in the cannister is
compatible with the apparatus for manufacturing spectacle lenses.
15. A gasket suitable for receiving and retaining two molds to form a
spectable lens form, said gasket comprising a hollow resilient body
having: a) opposed open ends; b) an inside surface extending between
the open ends; c) Two spaced apart slots extending about an inside
surface thereof. d) a resin inlet conduit and an outlet conduit, which
communicate between respective positions on the inside surface between
the annular slots, and positions on the outside of said body.
16. A gasket suitable for receiving and retaining two generally
circular molds to form a spectacle lens form, said gasket comprising a
hollow resilient body having: a) opposed open ends; b) an inside
surface extending between the open ends, of substantially circular
radial cross-section throughout the axial length thereof; c) two spaced
apart annular slots extending about the inside surface thereof; d) a
resin inlet conduit and an outlet conduit, which communicate between
respective positions on the inside surface between the annular slots,
and positions on the outside of said body.
17. A gasket as defined in claim 16, wherein said body has an annular
lip disposed between the slots, and which lip extends inward beyond the
inside surface.
18. A gasket as defined in claim 17, wherein the conduits communicate
with respective opposed positions on the inside surface.
19. A gasket suitable for receiving and retaining two molds to form a
spectacle lens form, the gasket comprising a resilient hollow body
having: a) opposed open ends; b) an inside surface extending between
the open ends, of substantially circular radial cross-section
throughout the axial length thereof; c) two spaced apart annular slots
on the inside surface thereof; d) an annular lip disposed adjacent and
between the slots and which extends inward beyond the inside surface;
e) a resin inlet and an outlet which communicate between respective
opposed inside positions on the inside surface between the annular
slots, and respective inlet and outlet ports spaced apart therefrom in
an axial direction of said body and which face in the same axial
direction.
20. A gasket as defined in claim 19 wherein said body had two radially
opposed and axially extending shoulders, and wherein the inlet and
outlet ports are disposed in respective axially facing ends of the
shoulders.
21. A gasket as defined in any of claims 16 to 20, wherein the body and
slots are dimensioned such that said body will tend to press molds with
annular flanges matingly retained in respective annular slots, toward
one another.
22. A gasket ad defined in claim 20 wherein said body is normally
outwardly bowed, and inwardly bowed when the mold annular flanges are
matingly retained in respective annular slots, so as to urge the molds
toward one another.
23. A mold suitable for molding a surface of a spectacle lens,
comprising: a) an annular flange having two diametrically opposed
notches therein; and b) a curved molding surface extending within said
annular flange.
24. A mold suitable for molding a surface of a spectacle lens,
comprising: a) an annular flange; b) a generally convex molding surface
defined by combined spherical and cylindrical elements such that two
opposed first surface portions disposed about the axis of least
curvature are coplaner with said flange, while two opposed second
surface portions disposed about the axis of greatest curvature, extend
past said annular flange; c) wall segments extending between the second
surface portions and said flange.
25. A mold as defined in claim 24 wherein said wall segments extend
perpendicularly to the plane on which said annular ring lies.
26. A form assembly apparatus capable of assembling a spectacle lens
form from two molds and a hollow gasket with opposed first and second
ends, which gasket is dimensioned to receive the molds therein in
respective, spaced apart, seated positions, the apparatus comprising:
a) a first mold retainer and a gasket holder which can releasably
retain a first mold and a gasket thereon, respectively; b) a
reciprocating drive connected to reciprocate one of said first mold
retainers and gasket holder with respect to the other when the two are
axially aligned, such that said first mold retainer can insert a first
mold retained thereon through the first open end of the gasket and into
its seated position to produce a sub-assembly; c) a second mold
retainer which can releasably retain a second mold thereon; d) a
reciprocating drive connected to reciprocate one of said second
retainer and the sub-assembly when axially aligned therewith, with
respect to the other, such that said second mold retainer can insert a
second mold retained thereon into its corresponding seated position in
the gasket of the sub-assembly to produce the assembled form; e) a
carriage connected to align the first mold retainer with said gasket
holder, and align the sub-assembly with said second mold retainer.
27. A for assembly apparatus capable of assembling a spectacle lens
form from two generally circular molds and a hollow gasket with a
generally circular cross-section therethrough and opposed first and
second ends, which gasket is dimensioned to receive the molds therein
in respective, spaced apart, seated positions, the apparatus
comprising: a) a first mold retainer and a gasket holder which can
releasably retain a first mold and a gasket thereon, respectively; b) a
reciprocating drive connected to reciprocate one of said first mold
retainers and gasket holder with respect to the other when the two are
axially aligned, such that said first mold retainer can insert a first
mold retained thereon through the first open end of the gasket and into
its seated position to produce a sub-assembly; c) a second mold
retainer which can releasably retain a second mold thereon; d) a
reciprocating drive connected to reciprocate one of said second
retainer and the sub-assembly when axially aligned therewith, with
respect to the other, such that said second mold retainer can insert a
second mold retained thereon into its corresponding seated position in
the gasket of the sub-assembly to produce the assembled form; e) a
carriage connected to align the first mold retainer with said gasket
holder, and align the sub-assembly with said second mold retainer.
28. An apparatus as defined in claim 27, additionally comprising an
indexer which can establish the initial relative rotational angle of
said molds prior to insertion of said second mold into the
sub-assembly, and rotate one with respect to the other to adjust the
relative rotational angle to a preselected value.
29. An apparatus as defined in claim 28 wherein said indexer comprises:
a) an index indicator on each of said mold retainers which can be
aligned with a corresponding indicator on the outer periphery of a
mold; b) motor means for rotating at least one of said mold retainers
with respect to the other.
30. An apparatus as defined in claim 29 wherein the index indicator on
each mold retainer, is a plurality of tabs thereon which can project
into mating receptacles on the outer periphery of a mold.
31. An apparatus as defined in claim 30 wherein the index indicator on
each mold, comprises two tables angularly spaced apart 180 degrees
about the axis of the mold retainer, which can project into matching
receptacles on the outer periphery of a mold.
32. An apparatus capable of assembling a spectacle lens form from two
generally circular molds and a hollow gasket with a substantially
circular cross-section therethrough and with opposed first and second
open ends, which gasket is dimensioned to receive the molds therein in
respective, spaced apart, seated positions, the apparatus comprising:
a) a first mold retainer and an oppositely facing gasket holder one of
which is reciprocally mounted with respect to the other such that when
the two are axially aligned, said first mold retianer can insert a
first mold retained thereon, through the first open end of the gasket
and into its seated position to produce a sub-assembly which can be
retained on the first mold retainer; b) a second mold retainer facing
in a direction opposite the first, one of which is reciprocably mounted
with respect to the other, such that when the two are axially aligned,
said second mold retainer can insert a second mold retained thereon
into its seated position in the gasket of the sub-assembly retained on
the aligned first mold retainer, to produce the assembled form; c) a
carriage upon which said first mold retainer is disposed, which can
carry said first mold retainer between respective positions in which it
is axially aligned with the gasket holder and said second mold
retainer; d) at least one reciprocating drive connected to reciprocate
one of the first mold retainer and gasket holder with respect to the
other, and one of the first and second mold retainers with respect to
the other.
33. An apparatus as defined in claim 32 wherein said carriage is
slideably mounted on a guide, and wherein at least one reciprocating
drive reciprocates said gasket holder and said second mold retainer
with respect to said first mold holder.
34. An apparatus as defined in claim 33, additionally comprising: a) a
form filling station having: (i) a table which can hold a form in
position thereon, and a form filler with a resin injection nipple; (ii)
a reciprocating drive connected to at least one of the table and the
filler so as to reciprocate at least one with respect to the other; the
table and form filler being disposed such that the resin injection
nipple can mate with an injection port of a form disposed on the table
when said reciprocating drive moves one of the table and filler toward
the other; d) a form carrier alignable with said second mold retainer
and the table, so as to receive a form from a position aligned with
said second mold retainer and hold it in alignment with the table.
35. An apparatus as defined in claim 34, additionally comprising: a) a
form filling station having: (i) a form table which can hold a form in
position thereon, and a form filler with a resin injection nipple and a
vacuum injection nipple; (ii) a reciprocating drive connected to at
least one of the table and the filler so as to reciprocate at least one
with respect to the other; said table and form filler being disposed
such that the resin vacuum injection nipples can mate with respective
resin and vacuum injection ports of a form disposed on the table, when
the reciprocating drive moves and one of the table and filler toward
the other; d) a form carrier alignable with said second mold retainer
and the table, so as to receive a form from a position aligned with
said second mold retainer and hold it in alignment with the table.
36. An apparatus capable of assembling a spectacle lens form from two
generally circular molds and a hollow gasket with a substantially
circular cross-section therethrough and with opposed first and second
open ends, which gasket is dimensioned to receive the molds therein in
respective, spaced apart, seated positions, the apparatus comprising:
a) an upwardly facing first mold retainer and a downwardly facing
gasket holder one of which is reciprocally mounted with respect to the
other such that when the two are axially aligned, said first mold
retainer can insert a first mold retained thereon, through the first
open end of the gasket and into its seated position to produce a
sub-assembly which can be retained on the first mold retainer; b) a
downwardly facing second mold retainer disposed transversely from said
first mold retainer in a forward direction, one of which is
reciprocably mounted with respect to the other such that when the two
are axially aligned, said second mold retainer can insert a second mold
retained thereon into its seated position in the gasket of the
sub-assembly retained on the aligned first mold retainer, to produce
the assembled form; c) at least one reciprocating drive connected to
can reciprocate the first mold retianer and gasket holder, and first
and second mold retainers, with respect to one another. d) a form
filling station spaced in the forward direction from said second mold
retainer, said form filling station having: (i) an upwardly facing form
table which can hold a form in position thereon, and a form filler with
a downwardly facing, resin injection nipple and a vacuum injection
nipple; (ii) a reciprocating drive connected to the table so as to
reciprocate the form table with respect to the form filler; said table
and form filler being disposed such that the resin and vaccum injection
nipples can mate with respective injection and vacuum ports of a form
disposed on the table, when the reciprocating drive moves the table and
filler toward the form filler; e) a form carrier alignable with said
second mold retainer and the table, so as to receive a form from the
former and hold it in alignment with the latter; f) a slideable
carriage upon which said first mold retainer and said form carrier are
disposed, said form carrier being spaced in the forward direction from
said first mold retainer, such that said carriage can align said first
mold retainer with each of said gasket holder and said second mold
retainer, and can align said form carrier with said second mld retainer
and the table.
37. Apparatus as defined in the claim 36 wherein said form carrier
comprises a rim which is open both from below and in a forward
direction, and wherein the form table when in a retracted position, is
disposed beneath the rim, and is dimensioned such that when the table
and said form carrier are axially aligned, the table can be extended
from the retracted position through said form carrier, to lift a form
disposed thereon to a position in which the injection and vacuum ports
mate with the resin and vacuum injection nipples, respectively.
38. A method of preparing a spectacle lens using a lens form having
resin and vacuum injection ports and respective conduits communicating
therefrom to substantially opposed outlet and inlet openings in the
mold cavity, the method comprising injection resin into the resin
injection port while applying a vacuum at the vacuum injection port.
39. A method as defiend in claim 38 additionally comprising tilting the
mold prior to resin injection such that the mold cavity is disposed at
an elevated angle to the horizontal, with the outlet opening being
higher than the inlet opening, and maintaining such an elevated angle
during resin injection.
40. A method as defiend in claim 39 wherein the elevated angle is
between substantially 6 degrees to 15 degrees.
41. A method of assembling a spectacle lens form from first and second
molds having respective flanges extending thereabout, and from a gasket
comprising a hollow resilient body having: (i) opposed first and second
open ends (ii) first and second slots extending about an inside surface
of the body, which can snugly seat therein, the flanges of the first
and second molds, respectively; (iii) a resin inlet conduit and an
outlet conduit which communicate between respective positions on the
inside surface between the annular slots, and positions on the outside
of said body; the method comprising pressing the first and second molds
through at least one open end of the gasket until the flange of each is
snugly seated in a corresponding slot.
42. A method of assembling a spectacle lens form from first and second
generally circular molds having respective annular flanges extending
thereabout, and from a gasket comprising a hollow resilient body
having: (i) opposed first and second open ends (ii) an inside surface
extending between the ends, with a substantially circular radial
cross-sections throughout its length; (iii) first and second annular
slots extending about the inside surface of the body, which can snugly
seat therein the flanges of the first and second molds, respectively;
(iv) an annular lip disposd adjacent end between the slots and which
extends inward beyond the inside surface; ; (v) a resin inlet and an
outlet which communicate between respective opposed inside positions on
the inside surface between the annular slots, and respective inlet and
outlet ports spaced apart therefrom in an axial direction of said body
and which face in the same axial direction; the method comprising
pressing the first and second molds through at least one open end of
the gasket until the flange of each is snugly seated in a corresponding
slot.
43. A chuck suitable for spin coating a spectacle lens mold, the chuck
comprising: a) a mold seat defined by a ledge, and an adjacent lip,
both extending about a seat axis; b) a lengthwise resiliant vacuum
conduit extending to an open first end thereof, said conduit being
disposed such that when a vacuum is applied therethrough, the open
first end can sealingly engage against the mold when seated in the mold
seat, to urge the mold against the ledge.
44. A chuck as defined in claim 43 wherein the lip projects from the
ledge in a first axial direction of the mold seat axis, and the vacuum
extends in the first axial direction toward the open end thereof.
45. A chuck suitable for spin coating a spectacle lens mold, the chuck
comprising a hollow body having: a) an open first and an opposed second
end; b) a wall extending between the ends; c) a mold seat defined by a
ledge extending adjacent an inside surface of the wall, and an
outwardly adjacent lip, both the ledge and lip extending about a seat
axis, and the lip projecting in a first axial direction of the seat
axis away from the second end; d) a lengthwise resilient vacuum conduit
extending in the first axial direction to an open first end thereof,
said conduit being disposed such that when a vacuum is applied
therethrough, the open first end can sealingly engage against the mold
when seated in the mold seat, to urge the mold against the ledge.
46. A chuck suitable for spin coating a spectacle lens mold, the chuck
comprising: a) a hollow body having a generally circular open first
end, an opposed second end, and a wall with a substantially
cylindirical inside surface extending between the ends; b) a mold seat
defined by a ledge extending adjacent the inside surface of the wall,
and an outwardly adjacent lip, both the lip ledge and lip extending
about a seat axis with the lip projecting in a first axial direction of
the seat axis away from the second end; c) a lengthwise resilient
vacuum conduit extending in the first axial direction to an open first
end thereof, said conduit being disposed such that when a vacuum is
applied therethrough, the open first end can sealingly engage against
the mold when seated in the mold seat, to urge the mold against the
ledge.
47. A chuck as defined in claim 46 wherein the second end of said body
has a lower vacuum opening aligned with the axis of the substantially
cylindrical wall, and a second end of said vacuum conduit communicates
therewith.
48. A chuck as defined in claim 46 wherein the seat axis is aligned
with the axis of the substantially cylindrical wall.
49. A chuck as defined in any of claims 43 to 48 wherein said vacuum
conduit comprises a bellows.
50. A chuck as defined in claim 46 wherein said body is substantially
cylindrical.
51. A spin coater element suitable for spin coating a spectacle lens
mold which has a flange extending around the outer periphery thereof,
the spin coater comprising: a) a frame; b) a chuck rotatably mounted on
said frame, said chuck comprising: i) a mold seat defined by a ledge,
and an adjacent lip, both extending about a seat axis; ii) a lenthwise
resilient vacuum conduit extending to an open first end thereof, said
conduit being disposed such that when a vacuum is applied therethrough,
the open first end can sealingly engage against the mold when seated in
the mold seat, to urge the mold against the ledge.
52. A spin coater element suitable for spin coating a spectacle lens
mold which has an annular outer flange, the spin coater comprising: a)
a frame; b) a chuck rotatably mounted on said frame, said chuck
comprising; i) a hollow body having a generally circular open first
end, an opposed second end, and a wall with a substantially cylindrical
inside surface extending between the ends; (ii) a mold seat defined by
a ledge extending adjacent the inside surface of the wall, and an
outwardly adjacent lip, both the ledge and lip extending about a seat
axis with the lip projecting in a first axial direction of the seat
axis away from the second end; iii) a lenthwise resilient vacuum
conduit extending in the first axial direction to an open first end
thereof, said conduit being disposed such that when a vacuum is applied
therethrough, the open first end can sealingly engage against the mold
when seated in the mold seat, to urge the mold against the ledge.
53. A chuck as defined in claim 52 wherein the second end of said body
has a lower vacuum opening aligned with the axis of the substantially
cylindrical wall, and a second end of said vacuum conduit communicates
therewith.
54. A chuck as defined in any of claims 51 to 53 wherein the vacuum
conduit comprises a bellows.
55. A spin coater comprising: a) a housing having separate front and
rear chambers separated such that light in the rear chamber is
substantially blocked from the front chamber; b) a drawer carrying at
least one spin coater element each of which is suitable for spin
coating a spectacle lens mold, said drawer being slideably mounted
within said housing to move between front and rear positions in which
the spin coater is disposed in the front and rear chambers,
respectively.
56. A spin coater as defined in claim 55, additionally comprising an
actinic light fixture disposed in the rear chamber, so that an actinic
light disposed therein can illuminate each spin coater element when
said drawer is in the rear position.
57. A spin coater as defined in claim 56 additionally comprising: a) a
shutter disposed in the rear housing between said light fixture and the
rear position of said drawer, said shutter being moveable between a
closed position in which the rear position of the drawer is shielded
from the light fixture, and an open position; b) a shutter trigger
connected between said shutter and said drawer, so as to open and close
said shutter, in response to said drawer moving rearwardly into, and
forwardly out of, the rear position, respectively.
58. A spin coater as defined in claim 55, additionally comprising an
actinic light fixture disposed in the rear chamber, so that an actinic
light mounted in said fixture can illuminate each spin coater element
when said drawer is in the rear position.
59. A spin coater as defined in claim 57 wherein said shutter comprises
two sheets hinged together in a sideways direction of said housing and
mounted to be forwardly and rearwardly pivotable about the hinge,
between open and closed positions, corresponding to open and closed
positions of the shutter, respectively, in which open position the
sheets are spaced apart at an interior angle greater than when in their
closed position.
60. A spin coater as defined in claim 58 wherein said shutter trigger
comprises a resilient member connected between said drawer and said
shutter, so as to open and close said shutter when said drawer moves
rearwardly and forwardly, respectively, of a position adjacent the rear
position.
61. A spin coater as defined in claim 60 additionally comprising a
reflector disposed in the rear chamber, and within which reflector said
actinic light fixture is disposed such that said reflector directs
light from said fixture to the spin coater elements when said drawer is
in the rear position.
62. A spin coater as defined in claim 60 wherein said shutter is
mounted in said reflector by means of guides on the sheets which ride
in corresponding slots in the reflector.
63. A method of producing a spectacle lens with abrasion resistant
front and back coated surfaces, the method comprising: a) providing a
partially polymerized coating composition on front and back surfaces of
a spectacle lens form, the composition on one of the surfaces having
lower solids content than the composition on the other; b) filling the
form with a lens resin, and curing the lens resin.
64. A method as defined in claim 63 wherein the composition on the back
surface of the method has a lower solids content that the composition
on the front surface.
65. A method as defined in claim 63 or 64 comprising further
polymerizing the front and back surface coatings, following curing of
the resin.
66. A method of producing a spectacle lens with abrasion resistant
front and back coated surfaces, one of which is tintable while the
other is not, the method comprising: a) coating front and back surface
molds with a polymerizable coating composition, the composition on the
mold corresponding to the tintable one of the lens surfaces having a
lower solids content than the composition on the other one of the
molds; b) partially polymerizing the coating composition; c) assembling
the molds within a gasket to produce a spectacle lens form; d) filling
the form with a lens resin, and curing the resin such that the
partially polymerized coatings will become only partially absorbed in
the cured lens resin; e) separating the coated lens from the form.
67. A method as defined in claim 66 wherein the composition on the back
has a lower solids content than the composition on the front mold.
68. A method as defined in claim 66 or 67 additionally comprising
further polymerizing the front and back surface coatings, following
curing of the resin.
69. A spectacle lens with abrasion resistant front and back coated
surfaces, produced by the method comprising: a) providing a partially
polymerised coating composition on front and back surfaces of a
spectacle lens form, the composition on one of the surfaces having
lower solids content than the composition on the other; b) filling the
form with a lens resin, and curing the resin.
70. A method of producing a spectacle lens with abrasion resistant
front and back coated surfaces, the method comprising: a) coating front
and back surface molds with a polymerizable coating composition, the
composition on the mold corresponding to the tintable one of the lens
surface having a lower solids content than the composition on the other
one of the molds; b) partially polymerizing the coating composition; c)
assembling the molds within a gasket to produce a spectacle lens form;
d) filling the form with a lens resin, and curing the resin such that
the partially polymerized coatings will become only partially absorbed
in the cured lens resin; e) separating the coated lens from the form.
71. A spectacle lens having abrasion resistant front and back coatings,
one of which is tintable while the other is not, the tintable surface
coating being less abrasion resistant than the other surface coating
and being partially absorbed on the back surface of the lens.
72. A spectacle lens as defined in claim 71 wherein the tintable
coating is on the back surface of the lens.

DESCRIPTION:
Each resulting lens 130a then, as shown in FIG. 11B has a lens body
132a of the cured lens resin, and a front coating 134a and back coating
136a. Where desired, the two lenses 130a can be placed upon respective
spin coaters 63a in a manner shown in FIG. 9B, with only a vacuum
through bellows 74a holding each in place. Thus, as shown in FIG. 9B,
lens 130a will be urged in the direction of arrows 132a. Since the lens
produced by the molds will have a diameter less than the outer diameter
of the molds themselves, it will not seat on the mold seat defined by
ledge and lip 70a, 72a, respectively.
However, the purpose of seating the coated lenses on spin coater 63a at
this stage does not require spinning of the coater, which instead
simply act as holders for lenses 130a while drawer 60a is slid to its
rear position, to further expose lenses 130a to actinic light from
light 28a and thereby further polymerize and harden coatings 134a,
136a.
A method which can use such spin coater (but which need not necessarily
do so) to produce a spectacle lens with front and back coatings with
desireable properties, and the resulting spectacle lens, will now be
described. Method of Making Coated Spectacle Lenses
As described in the "Summary of the Invention" above, the concept here
is to provide a first surface of a spectacle lens, preferably the front
surface, with a highly abrasion resistent non-tintable coating, while
providing a second surface, preferably the rear surface, also with a
coating which is abrasion resistent but not to the same degree as the
first surface coating, and which is tintable. Preferably the front
surface has an abrasion resistance of at least 80 psi as measured by
the method described below, and more preferably at least 200 psi, while
the back surface preferably has an abrasion resistance of at least
about 10 psi. It should be noted that typically coatings with an
abrasion resistance of less than about 75 psi, as determined by the
method described below, are typically tintable, whereas those with a
higher abrasion resistance typically are not.
In the following example, the front and back surfaces of the resultant
coated lens have the following characteristics:
Front surface: - abrasion resistance of 275 psi (pounds per square
inch), measured by the test method and associated apparatus described
below, and non-tintable.
Back surface: - abrasion resistance of approximately 10 psi, measured
as above (standard Allyl Diglycol carbonate lenses show approximately 5
psi abrasion resistance).
Tintability: - 70-80% transmission within 5 minutes at 200 F, and
63-67% transmission within 20 minutes at 200 F, using BPI GRAY
(available from Brain Power Incorporated, Miami, Florida, U.S.A. -
which is an aquaeous solution of a mixture of azo anthraquinone dyes of
approximately 5% (by weight) + 0.2% of a non-ionic surfactant. Example
1
Front coating is prepared by adding the following materials in order:
(sealed and stored at -5 F until used).
Columns=2> 63.10gram methy ethyl ketone (reagent grade). 1.40 gram 2,2
- dimethoxyl -1,2 -diphenylethanone (MWT 256.3). 30.80gram
dipentaerythritol pentaacrylate (MWT 525). 4.20gram ethoxylated
trimethylolpropane (MWT 428) 0.50 gram FC-430 (a trademark of 3M
Company, St. Paul, Minnesota, U.S.A.) surfactant (non-ionic fluorinated
alkyl esters) 100.00grams total
Back coating is prepared by adding the following materials in order:
(sealed and stored at -5 F until used.)
Columns=2> 93.81gram methy ethyl ketone (reagent grade) 0.40 gram 2,2 -
dimethoxy -1,2 - diphenylethanone (MWT 256.3) 2.00gram
dipentaerythritol pentaacrylate (MWT 525) 0.50gram polyethylene glycol
dimethacrylate (MWT 300) 2.50gram hydroxypropyl methacrylate (MWT 144)
0.79gram FC-430 surfactant 100.00grams total PROCEDURE 1.1 Clean front
molds are spin coated with the above front coating mix (mix allowed to
warm to room temperature before application), at 750 RPM. 1.2 Solvent
is evaporated with a 250 watt infrared bulb at a distance of 12 inches
for 1 minute, while being spun at 750 RPM.
1.3 The coated front mold is rotated at approximately 38 RPM while
exposing to ultraviolet U.V. light ("U.V.") using a medium pressure
mercury vapor light for 4 seconds at 19.6 milliwatts per square
centimeter measured at 360 nanometer wave length. 1.4 The back mold is
coated with the back coating (allowed to warm to room temperature) and
solvent evaporated as per 3.1.2 above, and exposed to U.V. as per 1.3
for 10 seconds. 1.5 The mold halves are assembled into a clear
polyvinyl chloride gasket having a shore "A" hardness of 75. 1.6 The
mold assembly is then filled through fill ports in the gasket with the
coating resin, a mixture of allyl diglycol carbonate, 3% isoperoxy
percarbonate (IPP) with shrink reduction additives. 1.7 The filled
assembly is cured in a horizontal flow forced air oven for 15 hours.
Temperature starts at 105 F and ramps to 145 F. 1.8 After 15 hours the
mold assemblies are cooled to 125 F, then demolded. 1.9 The resultant
lens are wiped clean with acetone and soft tissue, then placed back in
oven for post cure for 30 minutes at 200 F. 1.10 The post cured lenses
are then exposed to the U.V.; 60 seconds for front surface adn 20
seconds for back surface. 1.11 Abrasion tests are performed on the
front surface by the method described below. 1.12 Abrasion resistance
of the back coating was estimated by coating a front surface with back
coating and performing the abrasion test, RESULTS:
10 PSI 1.13 Tinting test Standard water soluble BPI gray dye at 200 F,
5 minutes - 70-80% transmission to visible light; and 20 minutes -
63-67% transmission to visible light 1.14 Adhesion Test A razor blade
was used to cross cut 1/16" squares on a 1/2" x 1/2" total area, then
the cross hatched area was pressed with adhesive tape and was then
peeled off. The lens sample is then placed in a tint bath for 5
minutes. Adhesion loss is observed on front or back lens as tinted
areas. This test is equivalent to ASTM Adhesion Tape Test No. D
3359-83, Method B. The coatings met standard 4B of the foregoing test,
that is with virtually no loss of adhesion. Abrasion Resistance Test
Method
The apparatus for measuring abrasion resistance is shown schematically
in FIG. 13B, and does not constitute a part of the present invention.
This apparatus includes a cam 2a which is driven by a motor (not shown)
so as to reciprocate a sample support 6a about a pivot point 8a in the
direction of arrows 12a. A sample 10a, in the form of a coated lens,
would be placed upon sample support 6a in the manner shown in FIG. 12B.
A steel wool pad 14a is arranged to contact the reciprocating sample
10a on sample support 6a, and be pressed thereagainst by means of a
load (i.e., weight) 20a acting through load transfer rod 18a, and
maintained in positioned by load transfer guide 16a. Load transfer rod
18a has a lower end with approximately 0.5 inch diameter, such that the
area of applied pressure to a sample is approximately 0.196 square
inch.
The foregoing apparatus is set up for measuring abrasion resistance as
follows: 2.1 The sample support is adjusted to move the sample on the
convex plane by proper radius selection at the pivot point for the
sample support. For example, a 6.00 Diopter ("D") surface d in FIG. 13B
will be: EMI73.1 Preferably a 4 to 6 D lens is used for the test, and
this should remain constant to reduce error in making comparisons
between tests. The stroke is set for 1.00 inch by the eccentric cam
position. The stroke speed of about one stroke per second is controlled
by selection of motor speed. One stroke is 2 passes across the surface.
2.3 The steel wool abrading pad is fine grade (#000) 3 x 4 inch, with a
compressed thickness of 0.25 inches.
The steel wool is wrapped around the end of the load transfer rod, the
steel wool strands perpendicular to the direction of sample motion, and
held tight with tape around the rod. 2.4 The lens sample is positioned
on the sample support with two sided tape, the front sample surface is
wiped clean with an acetone and a soft tissue wipe. 2.5 The load
transfer rod, with weights are allowed to rest freely on the lens
sample surface. 2.6 The motor is turned on and 25 strokes are counted
by a cycle counter device attached to a motor cam.
The motor stops automatically at the end of 25 strokes. 2.7 The load is
lifted away, the lens sample removed, wiped clean with acetone/soft
tissue, then visually inspected. 2.8 The visual inspection of the lens
sample is performed with the unaided eye, viewing through the back
surface, held 8-12 inches from the eye, viewing toward a ceiling
mounted fluorescent light. The number of visible continuous 1/4 inch,
or longer scratches, within the center most 1/2 inch of the stroke path
are counted. 2.9 A sample having 6 or more scratches constitutes
failure to exhibit abrasion resistance at a psi value which it
corresponds to the weight of load 20a. Less than 5 scratches is said to
exhibit abrasion resistance at such psi value.
It will be seen then, that the present invention provides both a spin
coater which can conveniently spin coat spectacle lens molds to provide
a means for coating a formed spectacle lens, and further provides a
novel vacuum chuck for automatically centering the mold in a chuck seat
and retaining it in position thereon by means of an axially resilient
vacuum conduit. In addition, as has also been disclosed, the present
invention provides a method for producing a coated spectacle lens with
one surface which is highly abrasion resistent, and another surface
which is not so abrasion resistant but has fairly significant abrasion
resistance, and which other surface remains tintable whereas the more
abrasion resistant surface is not.
Further, both coatings are partially absorbed onto the lens forming
material itself, and therefore adhere firmly thereto, by virtue of the
fact that the coatings were only partially polymerized when positioned
in a form and contacted with the uncured lens forming resin. In
addition, the present invention also provides a lens which can be
produced by the foregoing method.
It will be appreciated that various modifications and alterations can
be made to the substance of the above described inventions, without
departing from the spirit or scope thereof. Accordingly, the present
invnetion is not limited to the above described embodiments, but should
be determined with reference to the following claims.