U.S. patent application number 15/481335 was filed with the patent office on 2017-09-28 for methods and apparatus for cleaning blocked ophthalmic lenses.
The applicant listed for this patent is Shamir Optical Industry Ltd.. Invention is credited to Zohar KADMON, Ofer MARKMAN, Guy MECHREZ, Gil PERLBERG.
Application Number | 20170276568 15/481335 |
Document ID | / |
Family ID | 55652645 |
Filed Date | 2017-09-28 |
United States Patent
Application |
20170276568 |
Kind Code |
A1 |
MECHREZ; Guy ; et
al. |
September 28, 2017 |
METHODS AND APPARATUS FOR CLEANING BLOCKED OPHTHALMIC LENSES
Abstract
A blocked lens assembly suitable for on-block processing and
cleaning includes a blocked lens and a sealing member disposed on
at least a portion of an edge and/or surface defined by the blocked
lens. The blocked lens further includes a lens blank having a front
surface and a back surface, a lens blocking piece to hold the lens
blank while processing the back surface of the lens blank, and an
adhesive layer, disposed between the front surface of the lens
blank and the lens blocking piece, to affix the lens blank to the
lens blocking piece. The sealing member protects the blocked lens
so as to facilitate cleaning of the blocked lens while the lens
blocking piece is affixed to the front surface of the lens
blank
Inventors: |
MECHREZ; Guy; (Nesher,
IL) ; KADMON; Zohar; (Upper Galilee, IL) ;
MARKMAN; Ofer; (Upper Galilee, IL) ; PERLBERG;
Gil; (Zikhron Ya'akov, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Shamir Optical Industry Ltd. |
Upper Galilee |
|
IL |
|
|
Family ID: |
55652645 |
Appl. No.: |
15/481335 |
Filed: |
April 6, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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PCT/IB2015/002137 |
Oct 7, 2015 |
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15481335 |
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62060954 |
Oct 7, 2014 |
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62060959 |
Oct 7, 2014 |
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62060966 |
Oct 7, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 2021/9583 20130101;
B24B 13/0052 20130101; G01M 11/0278 20130101; B24B 13/005 20130101;
B08B 3/12 20130101; B24B 9/14 20130101; B29D 11/00009 20130101;
B29D 11/00923 20130101; G01N 21/8803 20130101; B29D 11/00942
20130101; G01M 11/0214 20130101; B29D 11/00865 20130101 |
International
Class: |
G01M 11/02 20060101
G01M011/02; B08B 3/12 20060101 B08B003/12; B29D 11/00 20060101
B29D011/00 |
Claims
1. A blocked lens assembly comprising: a blocked lens comprising: a
lens blank having a front surface and a back surface; a lens
blocking piece; and an adhesive layer, disposed between the front
surface of the lens blank and the lens blocking piece, to affix the
lens blank to the lens blocking piece; and a sealing member,
disposed along at least a portion of an edge of the blocked lens,
to facilitate cleaning of the blocked lens.
2. The blocked lens assembly of claim 1, wherein the lens blank has
a diameter approximately equal to a diameter of the lens blocking
piece.
3. The blocked lens assembly of claim 1, wherein at least a portion
of the edge of the blocked lens forms at least a portion of an edge
of the lens blank, an edge of the adhesive layer, and/or an edge of
the lens blocking piece.
4. The blocked lens assembly of claim 1, wherein the sealing member
comprises a dampening material.
5. (canceled)
6. The blocked lens assembly of claim 1, wherein the sealing member
comprises an elastic member substantially covering an edge of the
adhesive layer.
7. The blocked lens assembly of claim 1, wherein the adhesive layer
comprises an adhesive material and the sealing member comprises the
adhesive material.
8. (canceled)
9. The blocked lens assembly of claim 1, wherein a portion of the
sealing member extends beyond the back surface of the blocked lens
to support the blocked lens and to prevent contact between the back
surface of the blocked lens and the surface.
10. The blocked lens assembly of claim 9, wherein the portion of
the sealing member comprises at least one bumper.
11. (canceled)
12. The blocked lens assembly of claim 1, further comprising:
another adhesive layer to couple the sealing member to the at least
a portion of the edge of the blocked lens.
13. The blocked lens assembly of claim 1, wherein the sealing
member comprises a snap-on clamp.
14. (canceled)
15. The blocked lens assembly of claim 1, wherein the sealing
member comprises a locking mechanism to secure the sealing member
to the at least a portion of the edge of the blocked lens.
16. An apparatus for cleaning a blocked lens comprising a lens
blocking piece affixed to a front surface of a lens blank via an
adhesive layer, the blocked lens defining an edge substantially
covered by a sealing member, the apparatus comprising: at least one
container to hold a cleaning liquid; a holding member to hold at
least a portion of the blocked lens in contact with the cleaning
liquid during cleaning of the blocked lens; and an ultrasonic
transducer, acoustically coupled to the at least one container, to
transmit an ultrasonic wave into the cleaning liquid so as to clean
the blocked lens while the lens blank is affixed to the lens
blocking piece.
17. The apparatus of claim 16, wherein the holding member comprises
a basket having a mesh surface to receive an end portion of the
sealing member such that the back surface of the blocked lens is in
contact with the cleaning liquid.
18. The apparatus of claim 16, wherein the holding member
comprises: a first end to receive the sealing member; a second end
to couple the holding member to the container; and an arm, disposed
between the first end and the second end, to hold the back surface
of the blocked lens toward the cleaning fluid
19. The apparatus of claim 18, wherein the arm is a flexible arm to
enable motion of the blocked lens during cleaning.
20. (canceled)
21. The apparatus of claim 16, wherein the holding member comprises
a receptacle to secure the blocked lens at least partially
underneath the cleaning liquid during cleaning.
22-25. (canceled)
26. A method of cleaning a blocked lens comprising a lens blocking
piece affixed to a front surface of a lens blank via an adhesive
layer, the blocked lens defining an edge substantially covered by a
sealing member, the method comprising: A) disposing at least a
portion of the blocked lens in contact with a cleaning solution
while the lens blank is affixed to the lens blocking piece; and B)
transmitting an ultrasonic wave at a frequency of about 20 kHz to
about 250 kHz through the cleaning solution to clean the back
surface while the lens blank is affixed to the lens blocking
piece.
27. (canceled)
28. The method of claim 26, wherein the sealing member comprises a
water resistant film to protect the at least a portion of the
blocked lens from damage.
29. The method of claim 26, wherein A) comprises: disposing at
least a portion of the back surface of the blocked lens in contact
with the cleaning solution so as to clean the at least a portion of
the back surface.
30-41. (canceled)
42. The method of claim 26, wherein B) further comprises
transmitting the ultrasonic wave at a power level of about 10 Watts
to about 2000 Watts.
43-47. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a bypass continuation of International
Application No. PCT/IB2015/002137, filed Oct. 7, 2015, and entitled
"METHODS AND APPARATUS FOR CLEANING BLOCKED OPHTHALMIC LENSES,"
which in turn claims the priority benefit, under 35 U.S.C.
.sctn.119(e), of each of the following U.S. provisional
applications: Ser. No. 62/060,954, filed Oct. 7, 2014, and entitled
"METHODS AND APPARATUS FOR CLEANING BLOCKED OPHTHALMIC LENSES";
Ser. No. 62/060,959, filed Oct. 7, 2014, and entitled "METHODS AND
APPARATUS FOR REWORKING BLOCKED OPHTHALMIC LENSES"; and Ser. No.
62/060,966, filed Oct. 7, 2014, and entitled "METHODS AND APPARATUS
FOR VISUAL INSPECTION OF BLOCKED OPHTHALMIC LENSES." Each of the
prior applications identified above is hereby incorporated herein
by reference in its entirety.
BACKGROUND
[0002] The advent of two technologies has enabled a streamlined
method of producing complete prescription eyeglass lenses called
on-block manufacturing (OBM). The first technology is a plastic and
ultraviolet (UV) cured adhesive that allows lens blanks to be
coupled with a lens blocking piece, also known as a block, a
blocker, a lens chuck, or a surface block, that can hold lens
blanks for machining. The second technology is the Full Back Side
(FBS) digital surfacing technology, also referred to as free form
technology or free form generation, which allows the entire
prescription to be cut into the back (usually concave) surface of a
lens. By convention, the back or rear surface of the lens is the
surface closest to the wearer's eyes, and the front surface of the
lens is the surface opposite the back surface. For a typical
convex-concave lens, the front surface is convex and the back
surface is concave. Other lenses may be biconcave or biconvex, with
front and back surfaces that are both concave or both convex,
respectively.
[0003] FIG. 1 illustrates a conventional OBM process. In this OBM
process 100, based on a prescription, an appropriate lens blank
with a fully processed front (usually convex) surface is first
selected such that the OBM process only treats the back surface to
save manufacturing time and streamline the manufacturing process.
Then the lens blank is coupled to a lens block, in a step called
blocking, by gluing the front surface of the lens blank to the lens
block using a UV-cured adhesive. The lens block holds the lens
blank while the concave surface of the lens blank is machined to
fill the prescription. To further reduce manufacturing time, lens
blanks can be pre-blocked, i.e., the lens blank can be affixed to
the lens block before arriving at the OBM facility.
[0004] After the lens blank has been blocked (also referred to as
lens on block), its back surface is machined in two phases: a
coarse machining phase at step 110 to generate the overall shape
and diameter (e.g., using a generator), and a fine machining phase
at step 130 to polish the surface and achieve the desired surface
qualities. An engraving step 120 can be performed between the
coarse machining and the fining machining to engrave semi-visible
and/or visible marks on the lens to, for example, guide subsequent
manufacturing steps. After the back surface machining, the back
surface is usually cleaned at step 140 and dried at step 150 before
being coated with, for example, a hard coating at step 160 and/or
an anti-reflection coating at step 170. Then the coated lens is
removed, in a step 180 called deblocking, from the lens block for
edging, which involves cutting the lens into an appropriate shape
to fit the lens frame. An off-block inspection step 190 can be
performed after the lens is removed from the block. If the quality
of the de-blocked lens is satisfactory (e.g., no visible defect),
the de-blocked lens can be sent for edging at step 192, at which
step the de-blocked lens is machined to the desired shape to fit
eyeglass frames.
[0005] The OBM process can normally produce a pair of eyeglass
lenses in less than a business day or two. Depending on the
business model, some OBM labs offer a guaranteed delivery time of
less than 8 hours, less than 3 hours, or less than 90 minutes. The
guaranteed delivery time can be measured from receiving a
prescription to a point at which the framed eyeglasses are ready
for shipment. In some OBM labs, for example in urban areas, the
guaranteed delivery time can include the shipment as well.
[0006] Unfortunately, defects near (on or beneath) the back surface
of the lens blank may render the finished lens unsuitable. These
defects include but are not limited to scratches, dirt, cracks,
smudges, or pieces of lint on the lens surface. Defects may be
introduced during the machining process, the ultrasonic (US)
cleaning process, or just from exposure to the surrounding
environment during the OBM process. A hairline scratch on the lens
surface introduced during the fine machining phase, for example,
can cause a defective anti-reflection coating, reducing the
manufacturing yields. To increase manufacturing yield, a lens may
be cleaned before deblocking and subsequent coatings. Deblocking
and reblocking consumes extra time and can disrupt the OBM
process.
SUMMARY
[0007] Exemplary embodiments of the present invention include
methods and systems of cleaning a blocked lens while the lens blank
stays affixed on the lens blocking piece so as to avoid disrupting
the otherwise streamlined manufacturing process and improve the
manufacturing yield.
[0008] In one example, a blocked lens assembly suitable for
on-block processing and cleaning includes a blocked lens comprising
a lens blank having a front surface and a back surface, a lens
blocking piece to hold the lens blank while processing the back
surface of the lens blank, and an adhesive layer, disposed between
the front surface of the lens blank and the lens blocking piece, to
affix the lens blank to the lens blocking piece. The blocked lens
assembly also includes a sealing member, disposed on at least a
portion of an edge and/or surface defined by the blocked lens, to
protect the blocked lens so as to facilitate cleaning of the
blocked lens while the lens blocking piece is affixed to the front
surface of the lens blank.
[0009] The lens blank can have a diameter approximately equal to a
diameter of the lens blocking piece. In addition, the edge of the
blocked lens can form at least a portion of an edge of the lens
blank, an edge of the adhesive layer, and/or an edge of the lens
blocking piece.
[0010] The sealing member may comprise a dampening material, which
could include a high temperature polymer or a porous material. The
sealing member may also include an elastic member, such as a rubber
band, that substantially covers an edge of the adhesive layer. A
portion of the sealing member may extend beyond the back surface of
the blocked lens to support the blocked lens and to prevent contact
between the back surface of the blocked lens and the surface. This
portion of the sealing member can comprise at least one bumper
and/or define at least one notch. The sealing member may also
comprise a snap-on clamp, a quick-release clamp, and/or a locking
mechanism to secure the sealing member to at least a portion of the
edge of the blocked lens.
[0011] The adhesive layer and the sealing member comprise each
comprise the same adhesive material. They can also comprise
different adhesive materials (e.g., first and second adhesive
materials). And the blocked lens can further include another
adhesive layer to couple the sealing member to some or all of the
edge of the blocked lens.
[0012] In another example, an apparatus for cleaning a blocked lens
is disclosed. The blocked lens includes a lens blocking piece
affixed to a front surface of a lens blank via an adhesive layer.
The blocked lens also defines an edge and/or surface substantially
covered by a sealing member. The apparatus includes a container to
hold a cleaning liquid, a holding member, mechanically coupled to
the container, to hold at least a portion of the blocked lens in
contact with the cleaning liquid during cleaning of the blocked
lens, and an ultrasonic transducer, operably coupled to the
container, to transmit an ultrasonic wave into the cleaning liquid
so as to clean the blocked lens while the lens blank is affixed to
the lens blocking piece.
[0013] The holding member may comprise a basket or other receptacle
having a mesh surface to receive an end portion of the sealing
member such that the back surface of the blocked lens is in contact
with the cleaning liquid. The holding member may comprise a first
end to receive the sealing member, a second end to couple the
holding member to the container, and an arm, disposed between the
first end and the second end, to hold the back surface of the
blocked lens toward the cleaning fluid. In some cases, the arm may
be a flexible arm that enables motion of the blocked lens during
cleaning. The holding member may comprise a receptacle to secure
the blocked lens at least partially underneath the cleaning liquid
during cleaning. The holding member may also be configured to hold
a surface of the lens blocking piece in contact with the cleaning
fluid for cleaning the surface of the lens blocking piece.
[0014] The container may include a first container to hold a first
cleaning liquid and a second container to hold a second cleaning
liquid. The first cleaning liquid can be in contact with the back
surface of the blocked lens and the second cleaning liquid can be
in contact with a surface of the lens blocking piece. If desired,
the first cleaning liquid may be different than the second cleaning
liquid. Similarly, the ultrasonic transducer may comprises a first
ultrasonic transducer element operably coupled to the first
container and a second ultrasonic transducer element operably
coupled to the second container.
[0015] The apparatus may include a nozzle, operably coupled to a
pressurized fluid source, to provide a flow of liquid from the
pressurized fluid source toward the back surface of the blocked
lens.
[0016] In yet another example, a method of cleaning a blocked lens
is disclosed. The blocked lens includes a lens blocking piece
affixed to a front surface of a lens blank via an adhesive layer.
The blocked lens defines an edge and/or surface substantially
covered by a sealing member. The method includes disposing at least
a portion of the blocked lens in contact with a cleaning solution
while the lens blank is affixed to the lens blocking piece. The
method also includes transmitting an ultrasonic wave at a frequency
of about 20 kHz to about 250 kHz through the cleaning solution to
clean the back surface while the lens blank is affixed to the lens
blocking piece.
[0017] Before the blocked lens is placed in contact with the
cleaning solution, the sealing member may be disposed on the edge,
at least a portion of which forms at least a portion of an edge of
the lens blank, an edge of the adhesive layer, and/or an edge of
the lens blocking piece. This sealing member may comprise a water
resistant film to protect the at least a portion of the blocked
lens from damage.
[0018] At least a portion of the back surface of the blocked lens
may be disposed in contact with the cleaning solution for cleaning
the portion of the back surface. Likewise, at least a portion of
the lens blocking piece may be disposed in contact with the
cleaning solution so as to clean the portion of the lens blocking
piece. This may involve disposing at least a portion of the back
surface of the blocked lens in contact with a first cleaning
solution and disposing at least a portion of the lens blocking
piece in contact with a second cleaning solution to enable
simultaneous cleaning of the back surface of the lens blank and the
lens blocking piece.
[0019] The blocked lens can also be coupled, mounted, secured, or
otherwise affixed to a container. Then the liquid level of the
cleaning solution in the container can raised so as to dispose the
cleaning solution in contact with the blocked lens. The cleaning
solution can also be disposed above the back surface of the lens
blank and, if desired, the ultrasonic wave may provide a liquid
flow toward the back surface of the lens blank.
[0020] The cleaning solution may be prepared beforehand by mixing
water with a detergent at a volume percentage of about 0.1% to
about 10%, about 0.5% to about 6%, or about 1% to about 4%. The
cleaning solution can be heated (or cooled) to a temperature of
about 20.degree. C. to about 60.degree. C. (e.g., about 30.degree.
C. to about 50.degree. C.) for cleaning.
[0021] The frequency of the ultrasonic wave may be set within a
range from about 50 kHz to about 100 kHz (e.g., about 60 KHz to
about 90 KHz). The frequency of the ultrasonic wave can be tuned so
as to reduce the occurrence of hot spots, dead zones, and/or
standing waves on the concave surface of the lens blank. The
ultrasonic wave may be transmitted for about 50 seconds to about
500 seconds (e.g., about 100 seconds to about 250 seconds). And the
power level of the ultrasonic wave may be about 10 Watts to about
2000 Watts.
[0022] In some examples, the ultrasonic wave may comprise a
sequence of ultrasonic wave pulses that are generated and
transmitted through the cleaning solution to the back surface of
the lens blank. If desired, the back surface of the lens blank can
at least partially withdrawn from the cleaning solution while the
ultrasonic wave is propagating through the cleaning solution and at
least partially re-submerged in the cleaning solution while the
ultrasonic wave is propagating through the cleaning solution.
[0023] It should be appreciated that all combinations of the
foregoing concepts and additional concepts discussed in greater
detail below (provided such concepts are not mutually inconsistent)
are contemplated as being part of the inventive subject matter
disclosed herein. In particular, all combinations of claimed
subject matter appearing at the end of this disclosure are
contemplated as being part of the inventive subject matter
disclosed herein. It should also be appreciated that terminology
explicitly employed herein that also may appear in any disclosure
incorporated by reference should be accorded a meaning most
consistent with the particular concepts disclosed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The skilled artisan will understand that the drawings
primarily are for illustrative purposes and are not intended to
limit the scope of the inventive subject matter described herein.
The drawings are not necessarily to scale; in some instances,
various aspects of the inventive subject matter disclosed herein
may be shown exaggerated or enlarged in the drawings to facilitate
an understanding of different features. In the drawings, like
reference characters generally refer to like features (e.g.,
functionally similar and/or structurally similar elements).
[0025] FIG. 1 illustrates a conventional on-block manufacturing
(OBM) process.
[0026] FIG. 2 shows an exploded view of a blocked lens.
[0027] FIG. 3A shows a schematic view of a system for ultrasonic
cleaning of blocked lenses.
[0028] FIG. 3B shows a schematic view of a system including an
elastic holder for ultrasonic cleaning of blocked lenses.
[0029] FIG. 4A shows a schematic view of a seal disposed on a
blocked lens for protecting the blocked lens during cleaning.
[0030] FIG. 4B shows a schematic view of a snap that can be used
during blocked lens cleaning.
[0031] FIG. 4C shows a schematic view of a quick release seal that
can be used during blocked lens cleaning.
[0032] FIG. 4D shows a seal with bumpers that can be used during
blocked lens cleaning.
[0033] FIG. 5 shows a schematic view of a system including a basket
for cleaning blocked lenses by partially submerging the blocked
lens in a cleaning solution.
[0034] FIG. 6 shows a schematic view of a system including a
flexible seal for cleaning blocked lenses.
[0035] FIG. 7 shows a schematic view of a system including a fluid
source for cleaning blocked lenses.
[0036] FIG. 8 shows a system for cleaning blocked lenses with
cleaning solutions above the blocked lens.
[0037] FIG. 9 shows a schematic view of a system for ultrasonic
cleaning of blocked lenses with the back surface of the blocked
lens opposite the ultrasonic fluid surface.
[0038] FIG. 10 shows a schematic view of a system for ultrasonic
cleaning of blocked lenses with cleaning solution on both top and
bottom sides of the blocked lenses.
[0039] FIG. 11 shows a schematic view of a system for ultrasonic
cleaning of multiple blocked lenses.
[0040] FIG. 12 shows a schematic view of a system for cleaning
blocked lenses using high pressure steams.
[0041] FIG. 13 illustrates various types of defects that might
appear on the back surface of a blocked lens.
[0042] FIG. 14 illustrates a method of on-block cleaning of blocked
lenses.
DETAILED DESCRIPTION
[0043] Before detailed description of exemplary embodiments,
clarification of terms and parameters used in this application may
be helpful in understanding aspects of the disclosed technology.
Unless otherwise stated, in this specification: [0044] 1) The
concave surface of the lens blank can also be referred to as the
back surface, the rear surface, the posterior surface, or the
bottom of the lens; [0045] 2) The convex surface of the lens blank
can also be referred to as the front surface; [0046] 3) "Near a
surface" means on, below, and/or within the surface; for example,
lenses coated with multiple layers, "near" means on, below, and/or
within the coating layers; [0047] 4) A coating system: a coating
layer or a multi-layered structure comprising coating layers of
various thicknesses and material properties (see, e.g., FIG. 2);
[0048] 5) Coating system on front side: coating application
performed prior to blocking, that is prior to connecting the lens
to block; [0049] 6) Blocked lens (also referred to as a lens block
assembly, a Lens on Block (LOB), or a batch) refer to the assembly
of a lens blank coupled to a lens block (also referred to as block
piece, a blocking piece, or simply a block), including any adhesive
layers between the lens blank and the lens block, coating systems
on the front and/or rear surfaces of the lens blank, and any
adhesive layers and coating systems on the lens block; [0050] 7)
Damage to a coating layer can include, but is not limited to:
cracking, abrasion, delaminating, and changes in the coating
layer's mechanical, structural, thermal, or optical properties;
[0051] 8) Damage to a coating system can include, but is not
limited to: delaminating between coating layers, solvents (e.g.,
aqueous solutions and organic solutions) between coating layers,
swelling of solvents into the matrixes of the coating layers,
cosmetic defects (e.g., curing defects), changes to the physical
interactions among coating layers, changes in mechanical,
structural, thermal, or optical properties of the system, and
undesired adhesion between the upper most layer of the coating
system on the convex side of the lens blank and the lens block or
other surface; [0052] 9) Damage to a coating layer and/or a coating
system can include damage to the surfaces in which the coating
layer and/or the coating system interacts, such as the lens convex
surface, the lens concave surface, and/or the block surface. [0053]
10) The edge of the blocked lens (also referred to as the rim, lens
edge, or edge surface) refers to the outside limit of the blocked
lens, or the place or part of the blocked lens farthest away from
the center of the blocked lens. As used herein, the edge comprises
the surface and/or locus of points that define the circumference
(or boundary) of the lens blank in a blocked lens, the
circumference of the block piece in the blocked lens, and/or the
circumference of the adhesive layer and the coating system between
the lens blank and the block piece. In a side view (or cross
section view), the blocked lens edge can be seen as the thickness
of the lens, of the coating layer(s), of the adhesive layer and or
the block lens mounting surface. [0054] 11) Surface contaminants on
lens edge can include, but are not limited to: residue from the
machining and/or polishing processes, aluminum oxide, airborne
particles, and residual particles from the milling processes, swarf
(i.e., fine chips or filings of stone, metal, or other material
produced by a machining operation), bio-fouling, oil-based
contamination, organic contamination from handling and or from
material machining processes, mineral deposits based scale,
particles and precipitations; [0055] 12) Damage to the UV-curable
adhesive layer can include, but is not limited to changes in
viscosity, glass transition temperature, transparency to visible
light, color, tensile strength, Young's modulus, elongation at
failure, yield stress, and other optical, thermal, and mechanical
properties; [0056] 13) Properties of the adhesive layer after UV
curing include tensile strength, Young's modulus, torque strength,
peel strength, cross linking density, and heat capacity, wherein
the adhesive layer is normally between upper most layer of the
coating system on convex side and the block piece; [0057] 14) A
prescription of a lens can include parameters that specify the
desired properties of the lens and the processes of manufacturing
the lens; a prescription can be the output of a prescriptor, which
can convert a medical prescription provided by an eye care
professional (ECP) into a detailed instruction of lens
manufacturing, including optical power, surface shape, surface
roughness, dimensions, material, coating type, color, machines to
be used and their operating parameters, among others; [0058] 15) A
rework step can refer to one or more repeats of any of the steps in
the procedure of lens manufacturing, including machining,
polishing, cleaning, tinting, and coating, among others. A rework
step can be performed to correct a defect, to improve lens quality,
or to prepare the lens for subsequent processing (e.g., cleaning
rework); and [0059] 16) A rework loop can include one or more
manufacturing steps and their repeats to produce a desired property
of the lens. For example, a cleaning rework loop can include
cleaning-inspection-cleaning cycles until the surface cleanliness
satisfies certain standard.
[0060] Hereinafter, methods and systems for cleaning blocked lenses
are described with reference to the accompanying drawings.
[0061] A Blocked Lens
[0062] FIG. 2 shows an exploded view of a blocked lens suitable for
OBM processing (e.g., the process illustrated in FIG. 1). The
blocked lens 200 includes a lens blank 210, coating layers 220
deposited on the lens blank 210, an adhesive layer 230, and a lens
blocking piece 240 coupled with the lens blank 210 via the adhesive
layer 230. The lens blank 210 has a back surface 212, a front
surface 214, and a lens edge 216 between the back surface 212 and
the front surface 214. The lens edge 216 typically has a finite
thickness, e.g., about 5-13 mm, about 7-10 mm, etc., with
manufacturing tolerances of about 0.05 mm.
[0063] The front surface 214 of the lens blank is coated with the
coating layers 220, which can further include, for example, a hard
coating 222, an anti-reflection coating 224, a hydrophobic top
coating 226, and a grip coating 228, among others. Additional
coatings may include an anti-fog coating, a mirror coating, or a
polarization coating (not shown in FIG. 2). Since the coating
layers 220 and the front surface 214 in most cases are firmly
bonded together (e.g., via deposition processes), the front surface
214, when appearing in this specification, normally includes the
coating layers 220 unless otherwise specified. Accordingly, the
lens blank 210, when appearing in this specification, normally also
includes the coating layers 220 unless otherwise specified.
[0064] In an embodiment, the diameters of the lens 210, the block
240, and the adhesive layer 230 are substantially the same. In some
cases, the blocked lens 200 is machined during the coarse machining
phase at step 110 so that the diameters of the lens 210, the block
240 and the adhesive layer 230 are the same or about the same.
[0065] The front surface 214 (including the coating layers 220) is
affixed to the lens blocking piece 240 with the adhesive layer 230,
which can, for example, include an opaque resin dispersed with
carbon powders. More specifically, the adhesive layer 230 is
disposed in contact with the front surface 214 (or, more precisely,
with the top most coating layer, e.g., the grip coating 228 on the
front surface 214) and a receiving surface 244 defined by the lens
blocking piece 240 so as to couple the lens blank 210 with the lens
blocking piece 240. In one example, the adhesive layer 230 is cured
with ultraviolet (UV) light transmitted through the lens blank 210.
In another example, the adhesive layer 230 can be cured with UV
light transmitted through the lens blocking piece 240 from the
bottom. In this case, the lens blocking piece 240 defines an
exposed surface 242, through which the UV light can transmit and
reach the adhesive layer 230.
[0066] As shown in FIG. 2, the lens blank 210 defines the lens edge
216, the adhesive layer 230 defines an adhesive layer edge 232, and
the blocking piece 240 defines a block edge 246. During lens
manufacturing, these edges are typically exposed to the surrounding
environments (e.g., manufacturing machines, cleaning solutions,
drying air and/or heat, or dust, among others) and are therefore
susceptible to damage induced by the surrounding environments.
[0067] In current industry practices, most of the lens blanks 210
have a convex front surface 214 and a concave back (rear) surface
212. However, in some cases, the lens blank 210 may have a
bi-convex or bi-concave configuration, in which both surfaces 212
and 214 are convex, or concave, respectively. Or, the lens blank
210 may have a concave front surface 214 and a convex back surface
212. Conventionally, back surface 212 of a lens blank means the
surface closer to human eyes under normal wearing of eyeglasses,
and front surface 214 refers to the surface opposite the back
surface. Methods and apparatus described in this application can be
applied to all configurations of lens surfaces, although some
modifications (e.g., altering the surface of the lens blocking
piece to receive lens blank) may be helpful.
[0068] Cleaning a Lens Blank During Lens Manufacturing
[0069] Cleaning of lens blank, the lens blocking piece, or both can
be very helpful in lens manufacturing after polishing. For example,
the lens polishing process typically involves a chemical mechanical
process in which slurry is used to abrade and smooth the surface of
the lens. The slurry tends to leave minute residue and particles
that adhere to the concave surface. Therefore, it is beneficial to
clean the residues in promptly before the residues adhere to the
surface. It is also helpful to clean the residue gently since an
aggressive cleaning process (e.g., scrubbing the lens surface) can
degrade the polished surface of the lens which normally does not
have any protective coating immediately after polishing.
[0070] It is also very helpful to clean the lens immediately prior
to coating because even small debris, dust, contaminants, or oils
may affect the coating process and/or the quality of the resulting
coatings. There is also an advantage to conduct more than one
cleaning step in proximity to the coating process. In some cases
cleaning steps can be conducted in the coating machine itself.
[0071] A manual cleaning process (e.g., water-soap based using
cloths, sponges, brushes scrub the surfaces of the lenses) can be
employed to clean the lens blank during on-block lens
manufacturing. However, manual processes may introduce additional
defects, such as scratches, on the final lens product. Residues
that are not removed may compromise the coating layer that is
applied after the cleaning processes. Reworking the lens after
coating may remedy such defects, but reworking may be time
consuming and expensive. Manual cleaning also often involves
multiple steps and can be both time consuming and ineffective.
[0072] An alternative to manual cleaning can be ultrasonic cleaning
(also referred to as US cleaning) of lens during manufacturing and
post manufacturing. However, lenses manufactured on a block (OBM)
are typically taken off the block for ultrasonic cleaning to avoid
damage. After cleaning, the cleaned lens blanks are usually
re-blocked so as to allow subsequent processing steps, such as
coating, tinting, and edging, among others.
[0073] Submerging the LOB in an ultrasonic bath (also referred to
as a container, or a tank), or in a basket designed to support the
LOB in the ultrasonic fluid (also referred to as a cleaning liquid,
or a cleaning solution) can expose the lenses to high frequency
vibrations which can lead to collision of the lenses with
surrounding objects, including other LOBs and the containing
basket, causing damage in the form of chips, cracks, etc. This
problem can be exacerbated by the weight of the lens blocking
piece, which can increase the friction force (or impact, momentum)
at the point of contact between the lenses and other hard
surfaces.
[0074] Normally, lens cleaning is performed after the back surface
of the lens blank is machined. At this point in the production
process, the lens can be more susceptible to damage since the edges
of the lens blanks are thinned and therefore are more easily
cracked. The damage may also be more significant since it may be
within the edging perimeter (i.e., within the portion to be fitted
into eyeglass frames).
[0075] Ultrasonic cleaning may also cause damage on both micro
scale and macro scale to the various layers between the front
surface of the lens blank and the lens blocking piece. On the micro
scale (from about sub-micron to about 100 microns), cavitation
bubbles and the subsequent collapse (implosion) of these bubbles
may damage several surfaces, including the adhesive surface (e.g.,
230), hard coating surface (e.g., 222) and anti-reflection coating
surface (e.g., 224). For example, minute changes in adhesive
properties within the adhesive layer and or small vacancies in the
adhesive layer may cause stress concentration areas during the US
cleaning process. The stress concentration areas may cause
delimitation in nearby layers. Larger magnitude vibration of the
LOB system may affect the lens, coatings, and/or adhesive at a
scale from about 1 millimeter to about 80 millimeters. For example,
delamination may occur across the entire lens diameter, which can
be about 80 millimeters.
[0076] The coating on the convex side of the lens, including the
adhesion layer, may be especially susceptible to delamination. The
damage can be initiated when the edge of the LOB and the perimeter
of the coating and adhesion layer are exposed to the cavitation
bubbles induced by ultrasonic high frequency pressure on waves to
agitate the liquid. The damage includes delamination and or peeling
of the coating system, within the coating system layers and of the
adhesion layer.
[0077] The damage may manifest in concentric distortions on the
convex side of the lens in the central portion of the lens. The
damage can sometimes be visible to naked eyes, e.g. through the
concave surface, by viewing the LOB edges or from the block aspect.
The defects may be irreparable, i.e. rework does not cure the
defects in these cases.
[0078] FIG. 13 illustrates various forms of recurring defects that
may develop during conventional ultrasonic cleaning of blocked
lenses (e.g., at the cleaning step 140). Some of the defects can be
unique to ultrasonic cleaning on the block. Stated differently,
when lenses are cleaned off the block, these defects can be rare.
Defects shown in FIG. 13 include: delamination of the coating
system 220 on the convex surface, damage of the coating system 220
in proximity to the lens edge 1310 as seen from the concave
surface, damage of the coating system 220 on the convex surface,
damage in the center regions of the lens 1340 as seen from the
concave surface, delamination 1330 of the adhesive layer 230 from
the convex side coating layers 220 or the block mounting surface, a
hairline crack or chipping on the concave surface 1350, and/or a
hairline crack, or chipping on the lens edge surface 1360.
[0079] On-Block Lens Cleaning During OBM
[0080] In an exemplary On Block Manufacturing (OBM) process, the
rear surface of the lens blank 200 can be cleaned without removing
the lens blank from the lens block. Faster manufacturing of
eyeglass lenses can be achieved by eliminating the de-blocking and
reblocking steps. In one example, the cleaning can be performed by
an ultrasonic cleaner. In another example, a steam flow can be
applied to the lens back surface to clean residues. In yet another
example, both ultrasonic and steam cleaning can be deployed in a
sequence. In yet another example, water and soap can be used to
supplement the ultrasonic and/or steam cleaning.
[0081] FIGS. 3A-3B illustrate ultrasonic cleaning systems that uses
ultrasound (usually from 20-400 kHz) and an appropriate liquid
cleaning solvent to clean the back surface of the lens block while
it is on a block. In FIG. 3A, the system 300 includes two blocked
lenses 200 partially submerged in a cleaning solution 320 disposed
in a container 310 (also referred to as a tank or a bath) having a
rim 312. The back surfaces of the blocked lens 200 are in contact
with the cleaning solution 320. An ultrasound generating transducer
330 built into the chamber, or lowered into the fluid, then
produces ultrasonic waves in the fluid, creating compression waves
360 in the liquid to `tear` the liquid apart and leaving behind
many millions of microscopic `voids` or `partial vacuum bubbles`
(cavitation). These bubbles may release enormous energy when
collapsing: local temperatures and pressures on the order of 5,000
K and 20,000 lbs. per square inch can be achieved. The system 300
can further include an ultrasonic generator 340 operably coupled to
the ultrasonic transducer 330 via a cable 342. Without being bound
by any theory or mode of operation, the ultrasonic waves induce
cavitation that agitates the cleaning solvent. The agitation can
then produce high forces on contaminants adhering to substrates
like metals, plastics, glass, rubber, and ceramics. The ultrasonic
waves are also effective in cleaning contaminants in cracks and
recesses.
[0082] To mitigate, reduce, or eliminate damage induced by
vibration, the blocked lens 200 can be supported by an elastic
holder that dampens the high frequency vibration, as shown in FIG.
3B. The system 300 includes a blocked lens 200 supported by an
elastic holder 332 that dampens the high frequency vibration. For
example, the elastic holder may comprise a mechanical spring.
Alternatively, the elastic holder can include a component with
hardness in the range of about 30 A Shore to about 60 A Shore. The
elastic holder may also reduce low-frequency vibration such as
shaking. In one example, two types of holders may be used in
combination. For instance, during an ultrasonic cleaning mode in
which more than one ultrasound frequency is used, different holders
may be used to address each applied frequency.
[0083] In one example, only the back surface of the lens blank in a
LOB system is submerged in the solution, while the rest of the
system is either protruding from the solution (e.g., see FIGS.
3A-3B) or protected by a cover. For example, the LOB can be
disposed above the ultrasonic cleaning chamber such that primarily
the back surface of the lens blank is in contact with the cleaning
solution, and substantially the rest of the LOB is held above the
cleaning solution, as shown in FIG. 3B.
[0084] In another example, the circumference of the interface
between the lens blank and the lens blocking piece can be wrapped
with a layer of dampening material, such as sponge like materials,
plastic sheets, or other materials known in the art, while leaving
the surface to be cleaned exposed to the ultrasonic chamber medium.
The dampening material can also comprise rubber, rubber-tar
mixture, or other high temperature polymers (e.g., polymers capable
of withstanding temperatures of 40 to 120 deg. Celsius, 60 to 90
deg. Celsius, etc.). In operation, the dampening materials can
absorb incident ultrasound waves, thereby protecting the components
behind the dampening materials (i.e., the blocked lens, including
the adhesive layers and coating layers).
[0085] The cleaning solution 320 as shown in FIGS. 3A-3B can be
either aqueous or organic solutions. In aqueous cleaners, the
chemical added can be a surfactant (e.g., laundry detergent) which
can break down the surface tension of the water base. The cleaning
solution 320 can include mixture of detergent and water, with a
detergent concentration by volume of 0.1-10%, 0.5-6%, or 1-4%. In
one example, the detergent can be, for example, Deconex OP 171, and
de-ionized (DI) water may be used as the base for the solution.
Depending on the contamination type and size, the detergent type
and concentration may be adjusted to achieve desired cleaning.
Additional additives can also be included in the solution to modify
the fluid color.
[0086] In addition to the cleaning solution in the ultrasonic
cleaner chamber, other parameters that can be tuned to improve the
cleaning or reduce potential damage to the LOB include, but are not
limited to: the frequency of the ultrasound, operation mode,
cleaning time, ultrasound power, and cleaning temperature.
[0087] In operation, frequency of the ultrasound can determine the
spacing between the cavitation points. More specifically, higher
frequencies (or shorter wavelengths) produce smaller spacing, which
allows for cleaning of more intricate features. In one example, the
ultrasound frequency used for cleaning a LOB can be from about 20
KHz to about 250 KHz, from about 50 KHz to about 100 KHz, or from
about 60 KHz to about 90 KHz, depending, at least in part, on the
lens surface quality, contaminant size and type.
[0088] Different operation modes of the ultrasonic cleaner may be
implemented to further improve cleaning by targeting specific
contamination type and size. For example, in a normal mode, a fixed
ultrasonic frequency is applied throughout the entire cleaning
process to achieve general cleaning. In a sweep frequency mode,
continuous slight variation of ultrasonic frequency can be employed
to eliminate hot spots, dead zones, and standing waves. To remove
entrained air or other gases from liquids, intermittent operation
of ultrasonic power can be performed, e.g., as in a degas mode. As
to stubborn contaminants or degas solution, a pulse mode that
produces intense bursts of ultrasonic power can be selected. In
operation, multiple modes may be used in combination to further
improve cleaning.
[0089] Ultrasonic cleaning time, in one exemplary embodiment, can
be from about 15 seconds to about 1000 seconds, from about 50
seconds to about 500 seconds, or from about 100 seconds to about
250 seconds. In a streamlined process of lens manufacturing,
shortening the cleaning time without compromising the cleaning
results can be desirable. Moreover, excessive exposure to
ultrasonic cavitation and implosion may cause part damage. Reduced
cleaning time may be achieved by tuning other parameters such as
solution composition, solution temperature, cleaning mode,
ultrasound frequency, or any other parameters known in the art.
[0090] The power of the ultrasound normally determines the
amplitude of the sound waves generated and further determines the
agitation. More specifically, higher power can produce more
aggressive agitation, which can accordingly remove contaminants at
a faster speed. A practical range of ultrasound powers used in LOB
cleaning can be from 10 Watts to about 2000 Watts, within which the
power can be about 30 Watts to about 80 Watts, or from 80 Watts to
about 800 Watts, depending, for example, on the operation mode.
[0091] Cleaning temperature in LOB cleaning can be the temperature
of the liquid solution, or the temperature of the LOB itself. In
operation, it may be more convenient to change the solution
temperature. The fluid temperature in LOB cleaning can be from
about 20 degrees Celsius (.degree. C.) to about 90.degree. C., from
about 20.degree. C. to about 60.degree. C., or from about
30.degree. C. to about 50.degree. C. (e.g., 35.degree. C.,
40.degree. C., 45.degree. C., etc.). Generally, higher temperature
leads to faster molecular or atomic movement and therefore faster
cleaning. However, high fluid temperature may also corrode,
degrade, or damage the rest of the system, such as adhesive layer,
lens coating system, or the lens block. As a result, there usually
exists a range at which the ultrasonic cleaning can remove
contaminants without damaging the LOB.
[0092] Since the ultrasonic cleaning parameters (e.g., solution
composition, frequency of the ultrasound, operation mode, cleaning
time, ultrasound power, and solution temperature) can interact with
each other, a reduction in the magnitude of one parameter can, to a
point, be overcome by changing another parameter. For example,
increasing temperature or changing solution composition may reduce
the time required for ultrasonic cleaning. Furthermore, LOB
cleaning or the overall lens manufacturing processes may have
constraints on one or more variable. In one case, for example,
cleaning may be accomplished with a chemical that has a pH of about
7.+-.1 for compatibility with the material of the lens blank or
lens block. In another, the total cleaning time might be about 2
minutes or less to meet the desired production speed or yield. In
yet another, the temperature may be less than about 100.degree. C.,
90.degree. C., 80.degree. C., 70.degree. C., or 60.degree. C.,
depending at least on the LOB materials and cleaning solution, to
prevent damage to the LOB system
[0093] Potential damage to the blocked lens during ultrasonic
cleaning may be mitigated or minimized by developing an optimized
US cleaning process recipe (e.g., a collection of parameters used
in ultrasonic cleaning). The recipe may accomplish two goals
simultaneously: effective and efficient cleaning of the lens blank
while mitigating damage to the coatings and/or adhesion layer of
the convex side of the lens.
[0094] However, it may not be always easy or straightforward to
develop this recipe. Furthermore, properties of the LOB material,
the lens material, the adhesion layer, and the coating system in
each individual blocked lens may be slightly different from another
individual blocked lens. In some cases, the difference can be due
to different lens prescriptions and/or lens material. In some other
cases, the difference occurs due to different shelf life of the
blocked lens or any of its components. For example, the adhesion
layer properties may vary with age of the adhesion material.
[0095] Any difference in the properties may render the optimized
ultrasonic cleaning parameters for one blocked lens or one group of
blocked lenses out of the optimal parameter window. Minute changes
due to, for example, aging of the adhesion layer, or coating system
properties, may be insignificant for some manufacturing processes.
However, they can be significant for the ultrasonic cleaning
processes.
[0096] On-Block Ultrasonic Lens Cleaning Using a Sealing Member
[0097] Potential damage to the blocked lens during on-block
ultrasonic cleaning may be mitigated or minimized by creating a
physical barrier on the edge of the blocked lens and/or the
perimeter of the coating and adhesion layers so as to prevent
contact with the cleaning solution in ultrasonic cleaning
processes. The damage may be also be mitigated or minimized, by
partially submerging the LOB into the ultrasonic solution, such
that the coating and adhesive layers on the convex side the lens do
not come in contact with the cleaning solution.
[0098] FIG. 4A shows a schematic view of a blocked lens assembly
400 that can mitigate potential damage to blocked lenses during
on-block ultrasonic cleaning. The assembly 400 includes a blocked
lens that includes a lens blank with a front surface (not shown in
FIG. 4A) and a back surface 212, a lens blocking piece 240 to hold
the lens blank while processing the back surface of the lens blank,
and an adhesive layer, disposed between the front surface of the
lens blank and the lens blocking piece 240, to affix the lens blank
to the lens blocking piece. The assembly 400 also includes a
sealing member 420, disposed on at least a portion of an edge 440
defined by the blocked lens, to protect the blocked lens so as to
facilitate cleaning of the blocked lens while the lens blocking
piece is affixed to the front surface of the lens blank. The inner
surface 412 of the sealing member 420 is in contact with the edge
440.
[0099] The edge 440 includes an edge 216 of the lens blocking piece
240, the edge 232 of the adhesive layer, and the edge 246 of the
lens blank. In this case, the sealing member 420 can substantially
protect the adhesive layer from contacting with the cleaning
solution during ultrasonic cleaning processes.
[0100] The sealing member 420 has a first end portion 430 that
protrudes beyond the back surface 212 of the lens blank. In this
case, when the LOB is placed on an object with the back surface 212
facing the object, the first end portion 430 can support the LOB
and prevent contact between the back surface 212 and the object so
as to protect the optical surface of the back surface 212. The
sealing member 420 also has a second end portion 410 that can also
protrude beyond the perimeter of the edge 216 of the block 240.
[0101] In some examples, the sealing member 420 can include at
least one notch 435 (e.g., v-shaped recesses) in the first end
portion 430 such that only a portion of the first end portion 430
is touching the surface on which LOB system 400 is placed (e.g.,
ground). The notch 435 may also allow liquid to flow into and out
of the space defined by the first end portion 430 and the back
surface 212 of the lens blank. In some examples, the height (or
depth) of the notch 435 is up to the line defining the contact
between the back surface 212 and the sealing member 420, such that
the edge of the LOB and/or the perimeter of the coating and
adhesion layer does not contact the liquid while also allowing the
cleaning solution to reach the back surface 212 of the lens when
positioned face down in the cleaning solution.
[0102] In some examples, the sealing member can comprise a rubber
or rubber like material as known in the art. In some examples, the
sealing member 420 can be, for example, a rubber band and can be
mounted onto the blocked lens by stretching the sealing member 420.
In some examples, the sealing member 420 can comprises a heat
shrink material and can be applied to the blocked lens via heating.
In some examples, the sealing member is further reinforced with an
adhesive such that its bonding with the blocked lens is
stronger.
[0103] In some examples, the sealing member 420 is porous,
partially porous, or porous in some sections such that the sealing
member 420 can absorb energy released during the imploding of
cavitation bubbles in ultrasonic cleaning. In some examples, the
sealing member 420 comprises multiple layers and or materials. The
choice of materials can be dependent, for example, on the block and
lens material. In some examples, the sealing member 420 comprises a
material that is the same material used in the adhesive layer
between the lens and the block. In some examples, the sealing
member 420 can be applied in the same process to apply the adhesive
material. In some examples, the blocking of the lens blank onto the
lens blocking piece can be conducted within a ring that can
constrain the overflow of the adhesive material and shape the
adhesive material around the blocked lens so as to form the sealing
member 420.
[0104] FIG. 4B shows a schematic view of a snap-on clamp 460 with a
tooth locking mechanism 460 to secure the clamp 460 to a blocked
lens. The inner surface 412 of the snap-on clamp 460 can seal the
blocked lens from potential damage during ultrasonic cleaning.
[0105] FIG. 4C shows a schematic view of a quick release clamp 480
with a locking mechanism 484. The quick release clamp 480 can also
include a plurality of notches 485.
[0106] FIG. 4D shows a schematic view of a sealing member 490
including a plurality of bumpers 494 (also referred to as
cushioning mechanism) on the rim of the sealing member 490. The
bumpers 494 can provide additional protection for the back surface
212 when the blocked lens is placed, for example, on a surface with
the back surface 212 facing the surface. The clamps shown in FIGS.
4B-4D are about 1-5 mm larger than the thickness of the lens. But
the clamps can also be smaller than the thickness of the lens. For
example, the clamps' heights could be about 0.5-20 mm, 0.5-5 mm,
4-10 mm, 8-15 mm, 10-20 mm, etc.
[0107] Examples of On-Block Ultrasonic Lens Cleaning Systems
[0108] FIG. 5 shows a schematic view of a system to implement
on-block ultrasonic cleaning of blocked lenses. The blocked lens
400 includes a lens blocking piece affixed to a front surface of a
lens blank via an adhesive layer. The blocked lens also defines an
edge substantially covered by a sealing member 420. The system
includes a container 310 to hold a cleaning liquid 320, a holding
member 500, mechanically coupled to the container 310, to hold at
least a portion of the blocked lens 400 in contact with the
cleaning liquid 320 during cleaning of the blocked lens. The system
also includes an ultrasonic transducer 330, operably coupled to the
container 310, to transmit an ultrasonic wave into the cleaning
liquid 320 so as to clean the blocked lens 400 while the lens blank
is affixed to the lens blocking piece.
[0109] In one example, the sealing member 420 can be removed
before, for example, coating. In this case, the sealing member 420
can be bonded to the blocked lens 400 via a light adhesive.
Possible residues on the edge can be cleaned before coating. In
another example, the blocked lens 400 can undergo coating with the
sealing member 420, which can cover residue on the edge.
[0110] In some examples, the blocked lens 400 can be mounted onto a
flexible sealing member 420 which can be further mounted onto the
container 310. The flexible sealing member 420 can secure the
blocked lens 400 to the container 310 while at the same time
providing the blocked lens 400 with some degrees of motion during
the ultrasonic cleaning process.
[0111] In some examples, the holding member 500 can include a
receptacle, such as basket having a mesh bottom surface 510, for
holding the blocked lens 400 in the cleaning solution. In some
embodiments, the basket 500 is made of steel and/or other metal.
The basket and specifically the mesh can also be made of a polymer
material. The basket may be designed such that it can be placed on
the container 310, such that the bottom of the mesh is lower than
the container rim while other portions of the basket's frame or
structure are in contact with the container rim and support the
basket. In some examples, air or gas bubbles may be trapped in the
volume defined by back surface of the lens and the seal, as in an
upside down cup when it is lowered into a liquid. The trapped gas
bubbles may reduce the effectiveness of the US cleaning
process.
[0112] The basket 500 with the blocked lens 400 can be placed in
the fluid at an angle such that fluid may displace trapped gas
bubbles before starting the US cleaning process. In some
embodiments, the blocked lens 400 is vibrated and or slightly
tilted during the cleaning process such that gas bubbles are
displaced by fluid. In some examples, the basket 500 with the
blocked lens 400 is agitated such that the cleaning fluid 320 can
contact the back surface 212 of the lens blank prior to applying
the ultrasonic power. In some examples, the blocked lens 400 can be
placed in the basket 500 at an angle such that such that the fluid
can contact the concave aspects of the lens.
[0113] FIG. 6 shows a schematic view of a system for ultrasonic
cleaning of blocked lens using flexible holding members. The system
includes a blocked lens 400 protected by a sealing member 420,
which is further fastened to the rim of a container 310 via an end
portion 610 of a holding member 600. The holding member 600 can be
made of flexible materials such as rubber, plastic, or any other
flexible materials known in the art, that are formed or positioned
to hold the blocked lens 400 at least partially with the cleaning
solution. The holding member 600 can allow flexible movement of the
blocked lens 400 before, during, or after ultrasonic cleaning
processes. In this configuration the blocked lens is not in direct
contact with any hard surfaces. The flexible holding member 600
enables the use of containers with variable dimensions (e.g.,
width/diameter), depending on the elasticity of the seal. Gravity
or a pressure force exerted from above the blocked lens can achieve
the submersion of the concave side of the lens into the fluid.
[0114] In some examples, the blocked lens 400 can be pressed into
the sealing member 420 after the holder member 600 is mounted to
the container 310. In some examples, the blocked lens 400 can be
pressed into the sealing member 420 before the holder member 600 is
mounted to the container 310.
[0115] In some examples, the blocked lens 400 can be pressed onto a
flexible sealing member 420 wherein the flexible sealing member 420
is primarily in contact with the lens outer diameter. In some
examples, the blocked lens can be pressed onto a flexible sealing
member 420 wherein the flexible sealing member 420 has a diameter
that is smaller than that of the lens and the sealing member 420 is
pressed onto the perimeter of the concave surface. In some
examples, the sealing member 420 and the holding member 600 can be
integrated as a single unit. In some examples, the sealing member
420 and the holding member 600 can be separable.
[0116] FIG. 7 shows a schematic view of a system for on-block
ultrasonic cleaning of blocked lens with a pressured fluid source.
The system includes a blocked lens 400 fastened to the rim of a
container via a rigid holding member 700. More specifically, the
holding member 700 includes a first end 710 connected to the rim of
the container and a second end 715 connecting to the sealing member
420 enclosing the edge of the blocked lens 400. The system also
includes a pressurized fluid source 720 with a nozzle 722 to
provide fluid to the container or fluid flow to clean the back
surface 212 of the blocked lens.
[0117] In some examples, the blocked lens is mounted above the
pressurized fluid source nozzle 722 such that the flow of
pressurized fluid expels gas trapped near the concave surface of
the lens. In some examples, the container may have a window or
gauge (not shown) to monitor the fluid level. In some examples, a
pressure relief valve 725 in the holding member 700 can be used to
relieve pressure in the container when necessary. The pressure
relief methods can be accomplished with various mechanisms, located
in various positions in the system, for example, in the wall of the
tank 310.
[0118] In some examples, the system can further include a gas
diaphragm (e.g., a balloon, or any other flexible cavity with
expandable volume) which can be expanded or deflated so as to
adjust the liquid level in the container. The diaphragm can be
mounted within the container. In some examples, the diaphragm can
be submerged in the container. In some examples, an external pump
can be used to control the gas pressure within the diaphragm and
therefore the diaphragm size. An expansion of the diaphragm can
raise the fluid level toward the concave surface of the lens. In
some examples, there is a pressurized fluid source connected to the
tank. Once the lens is mounted and sealed, the tank is filled with
fluid.
[0119] FIG. 8 shows a schematic view of a system for on-block
ultrasonic cleaning of blocked lens with cleaning fluids above the
back surface of the blocked lenses. The sealed blocked lens (i.e.,
blocked lens with a sealing member) is mounted in a receiving
fixture (receptacle) 815, which is constructed using a material
designed to grip the seal. The fixture 815 can be at the bottom of
the container. In operation, after the concave surface of the lens
has been sealed and mounted, the container can be rotated above a
rotation axis that can be a horizontal line in the paper plane. The
rotation can be carried out using a pivot 820 such that the concave
surface of the lens functions as part of the bottom of the
container. In an embodiment, the blocked lens can be mounted when
the container is empty and then the container can be rotated to
fill the cleaning fluid. Once the system is rotated the fluid level
no longer has to be raised to the lens since the lens is at the
lowest point in the system. This system configuration may use less
fluid than other "blocking piece facing up" system configurations.
In addition, the gravity force of the cleaning liquid may increase
the efficiency of cleaning.
[0120] FIG. 9 shows a schematic view of a system for cleaning the
lens blocking piece. Coating processes in lens manufacturing
normally are performed in a clean environment. The coating machine
is typically sealed and transfers the parts to be cleaned between
internal stations deploying sub processes related to the coating
processes such as: rinsing, drying, surface preparation, and
coating, among others. In some cases, prior to placing the blocked
lens in the coating machine, a cleaning step can be performed to
clean the lens blocking piece. The system shown in FIG. 9 includes
a blocked lens fastened to the rim of the container with a flexible
seal (including both a sealing member 420 and a holding member 600)
that protects the interface between the lens blank and the lens
blocking piece. The lens blocking piece is submerged in the
cleaning solution for ultrasonic cleaning. All techniques described
above can be applied in this example to clean the lens blocking
piece. For example, the blocked lens 400 can be held in any of the
methods described above such that the lens blocking piece can be in
contact with the cleaning fluid.
[0121] FIG. 10 shows a schematic view of a system for ultrasonic
cleaning of both the lens blank and the lens blocking piece. In
FIG. 10, the blocked lens can be disposed in any of the methods
described above such that the lens blocking piece is in contact
with the cleaning fluid in one container and the lens blank is
disposed in contact with the cleaning fluid in a different
container. The two containers can be aligned and/or connected
without exposing the lens edge and/or the perimeter of the coating
and/or adhesion layer to the cavitation bubbles in ultrasonic
cleaning.
[0122] In some examples, the lens blank and the lens blocking piece
can be cleaned simultaneously. In some examples, the lens blank and
the lens blocking piece can be cleaned in a sequence without
physically moving the blocked lens.
[0123] In some examples, the two containers can hold the same
cleaning liquid. In some examples, the two containers can hold
different cleaning liquids. For example, one cleaning liquid can be
particularly for cleaning the lens surface which can be glass while
the other cleaning liquid can be particularly for cleaning the lens
blocking piece which can be plastic or polymer.
[0124] The system shown win FIG. 10 can saves time during lens
manufacturing by eliminating the need of, for example, moving the
blocked lens from one container to another or flipping the blocked
lens so as to clean the lens blocking piece. The system shown in
FIG. 10 may also save space by, for example, vertically stacking
the two containers.
[0125] In some examples, the ultrasonic cleaning liquid can be
heated so as to adjust the cleaning efficiency. For example, a
heating element, such as a heating resistor, can be installed near
the wall of the container.
[0126] FIG. 11 shows a schematic view of a system for on-block
ultrasonic cleaning of a plurality of blocked lenses. In FIG. 11,
multiple blocked lenses with protective sealing members can be
submerged in the cleaning fluid and supported by a basket or
perforated tray substantially like the one shown in FIG. 5. The
edges of the lenses are protected from impact and ultrasonic
interference by the sealing members. Any of the above methods
(e.g., as shown in FIGS. 5-10) can be applied on two or more
blocked lenses here.
[0127] In some embodiments, the ultrasonic cleaning system is
enclosed within the coating equipment. In some embodiments the US
cleaning system is an integral part of the coating equipment,
controlled by the machine control system. In some embodiments, the
ultrasonic cleaning system can function externally and/or
internally, with respect to the coating equipment, such that a
first cleaning can be applied externally to the coating equipment
and a second cleaning, within the coating machine enclosure and
clean environment.
[0128] Several methods can be employed to reduce or even eliminate
possible damage to the LOB system during ultrasonic cleaning. In
one example, repeated submerging of the LOB into the chamber can be
employed. Instead of keeping the LOB system soaked in the cleaning
solution, the LOB may be pulled out of the solution from time to
time to reduce the total interaction time with the solution,
therefore reducing the potential for damage caused by the
solution.
[0129] In some examples, the ultrasonic cleaning process can be
integrated with additional cleaning processes such as rinse and
dry, or pressurized steam cleaning. In some examples, the
additional cleaning steps can be conducted in the same container as
used in ultrasonic cleaning, e.g., by evacuating the ultrasonic
cleaning fluid after ultrasonic cleaning and introducing rinsing
fluid into the container. In some examples, the blocked lens with
or without the sealing member are moved to different stations where
rinse, dry and similar processes can be performed.
[0130] FIG. 12 shows a schematic view of a system in which the
concave surface of the lens on block is cleaned with high pressure
steam. The system includes a blocked lens 300 mounted to a
container via a holding member 700. The back surface 212 of the
blocked lens is toward a plurality of steam nozzles 1240 that can
provide high pressure steams 1250 to clean the back surface
212.
[0131] A steam cleaner normally uses steam expansion to accelerate
fluid droplets, at the boiling point, to a high velocity for
cleaning. The closer the steam cleaner nozzle 1240 is to the
surface to be cleaned, the higher the temperature and velocity of
the fluid/steam mixture, and the more rapid the cleaning action.
The temperature of the fluid/steam mixture may drop quickly as the
distance between the nozzle and the surface to be cleaned
increases. In an embodiment, the distance between the nozzle and
the surface to be cleaned is determined based on the lens material
and/or residue properties.
[0132] The cleaning can be performed either before coating, after
coating, or both depending on specific needs. For example, to
ensure high quality coating, cleaning can be performed before
coating. Or, to inspect the anti-reflection coating or hard coating
for quality assurance, cleaning can be performed after coating.
Furthermore, cleaning, followed by an inspection, can also be
carried out before edging, since it can be more difficult to rework
the concave surface if defects are identified after edging.
[0133] In FIG. 12 the lens is cleaned with pressurized steam 1250.
In one example, the steam cleaning process can be applied before
the ultrasonic cleaning. In another example, the steam cleaning
process can be applied after the ultrasonic cleaning.
[0134] In some examples, the blocked lens can be mounted within a
holder, such that the concave surface 212 of the lens blank is
facing toward the incident steam 1250 flow used for cleaning. The
holder 700 includes components that are in contact with the
circumference of the blocked lens such that fluid or gas flow can
be obstructed from the rest of the system behind the concave
surface. In some examples, a high pressure steam nozzle 1240 can be
positioned primarily below the concave surface 212 of the lens on
block 200, such that the pressurized steam is directed in the
direction of the concave surface. In some examples, the blocked
lens can be rotated around its geometric axis such that the steam
can be applied more uniformly over the concave surface for
cleaning. Alternatively, the nozzle 1240 can also rotate to achieve
uniform cleaning. Moreover, the LOB 200 system can undergo a
precession movement to clean surface areas further away from the
center.
[0135] To further improve cleaning, the distance between the nozzle
1240 and the concave surface 212 can be adjusted to tune the speed,
temperature, and chemical concentration of the cleaning steam. The
steam flow 1250 can be substantially perpendicular to the concave
surface for cleaning. Or, the steam flow 1250 can be directed upon
the concave surface 212 at an incident angle from about 90 degrees
(normal incidence) to about 5 degrees (grazing incidence).
[0136] FIG. 14 shows a flowchart that illustrates one example
method of on-block ultrasonic cleaning of blocked lenses in a OBM
process. The method 1400 can start from polishing at step 130,
after which the blocked lens is mounted in a sealing member at step
1410. The sealing member can be, for example, a snap on seal 460,
or a quick release seal 480 as described before. Then the sealed
blocked lens can be mounted to a container that can hold cleaning
solutions at step 1420. At step 1430, the blocked lens is brought
into contact with the cleaning solution. For example, the liquid
level of the cleaning solution in the container can be raised so as
to reach the blocked lens. The selected solution can be, for
example, DECONEX detergent, 12PA-x, elam lab clean A25, elam lab
clean S20, or any other suitable solution.
[0137] At step 1440, ultrasonic waves are applied toward the
blocked lens, with parameters optimally selected (e.g., at a
frequency of 80 kHz and 50% of maximal power). The blocked lens is
then removed from the seal for rinsing at step 1460 (e.g., using
tap water to remove residues of the cleaning solution in ultrasonic
cleaning). The blocked lens can also undergo several optional
cleaning cycles before removing the seal at step 1470. At step 140,
the blocked lens removed from the seal can be dried, for example,
using heat air or cold air flow.
CONCLUSION
[0138] While various inventive embodiments have been described and
illustrated herein, those of ordinary skill in the art will readily
envision a variety of other means and/or structures for performing
the function and/or obtaining the results and/or one or more of the
advantages described herein, and each of such variations and/or
modifications is deemed to be within the scope of the inventive
embodiments described herein. More generally, those skilled in the
art will readily appreciate that all parameters, dimensions,
materials, and configurations described herein are meant to be
exemplary and that the actual parameters, dimensions, materials,
and/or configurations will depend upon the specific application or
applications for which the inventive teachings is/are used. Those
skilled in the art will recognize, or be able to ascertain using no
more than routine experimentation, many equivalents to the specific
inventive embodiments described herein. It is, therefore, to be
understood that the foregoing embodiments are presented by way of
example only and that, within the scope of the appended claims and
equivalents thereto, inventive embodiments may be practiced
otherwise than as specifically described and claimed. Inventive
embodiments of the present disclosure are directed to each
individual feature, system, article, material, kit, and/or method
described herein. In addition, any combination of two or more such
features, systems, articles, materials, kits, and/or methods, if
such features, systems, articles, materials, kits, and/or methods
are not mutually inconsistent, is included within the inventive
scope of the present disclosure.
[0139] The above-described embodiments can be implemented in any of
numerous ways. For example, embodiments of designing and making the
coupling structures and diffractive optical elements disclosed
herein may be implemented using hardware, software or a combination
thereof. When implemented in software, the software code can be
executed on any suitable processor or collection of processors,
whether provided in a single computer or distributed among multiple
computers.
[0140] Further, it should be appreciated that a computer may be
embodied in any of a number of forms, such as a rack-mounted
computer, a desktop computer, a laptop computer, or a tablet
computer. Additionally, a computer may be embedded in a device not
generally regarded as a computer but with suitable processing
capabilities, including a Personal Digital Assistant (PDA), a smart
phone or any other suitable portable or fixed electronic
device.
[0141] Also, a computer may have one or more input and output
devices. These devices can be used, among other things, to present
a user interface. Examples of output devices that can be used to
provide a user interface include printers or display screens for
visual presentation of output and speakers or other sound
generating devices for audible presentation of output. Examples of
input devices that can be used for a user interface include
keyboards, and pointing devices, such as mice, touch pads, and
digitizing tablets. As another example, a computer may receive
input information through speech recognition or in other audible
format.
[0142] Such computers may be interconnected by one or more networks
in any suitable form, including a local area network or a wide area
network, such as an enterprise network, and intelligent network
(IN) or the Internet. Such networks may be based on any suitable
technology and may operate according to any suitable protocol and
may include wireless networks, wired networks or fiber optic
networks.
[0143] The various methods or processes (e.g., of designing and
making the coupling structures and diffractive optical elements
disclosed above) outlined herein may be coded as software that is
executable on one or more processors that employ any one of a
variety of operating systems or platforms. Additionally, such
software may be written using any of a number of suitable
programming languages and/or programming or scripting tools, and
also may be compiled as executable machine language code or
intermediate code that is executed on a framework or virtual
machine.
[0144] In this respect, various inventive concepts may be embodied
as a computer readable storage medium (or multiple computer
readable storage media) (e.g., a computer memory, one or more
floppy discs, compact discs, optical discs, magnetic tapes, flash
memories, circuit configurations in Field Programmable Gate Arrays
or other semiconductor devices, or other non-transitory medium or
tangible computer storage medium) encoded with one or more programs
that, when executed on one or more computers or other processors,
perform methods that implement the various embodiments of the
invention discussed above. The computer readable medium or media
can be transportable, such that the program or programs stored
thereon can be loaded onto one or more different computers or other
processors to implement various aspects of the present invention as
discussed above.
[0145] The terms "program" or "software" are used herein in a
generic sense to refer to any type of computer code or set of
computer-executable instructions that can be employed to program a
computer or other processor to implement various aspects of
embodiments as discussed above. Additionally, it should be
appreciated that according to one aspect, one or more computer
programs that when executed perform methods of the present
invention need not reside on a single computer or processor, but
may be distributed in a modular fashion amongst a number of
different computers or processors to implement various aspects of
the present invention.
[0146] Computer-executable instructions may be in many forms, such
as program modules, executed by one or more computers or other
devices. Generally, program modules include routines, programs,
objects, components, data structures, etc. that perform particular
tasks or implement particular abstract data types. Typically the
functionality of the program modules may be combined or distributed
as desired in various embodiments.
[0147] Also, data structures may be stored in computer-readable
media in any suitable form. For simplicity of illustration, data
structures may be shown to have fields that are related through
location in the data structure. Such relationships may likewise be
achieved by assigning storage for the fields with locations in a
computer-readable medium that convey relationship between the
fields. However, any suitable mechanism may be used to establish a
relationship between information in fields of a data structure,
including through the use of pointers, tags or other mechanisms
that establish relationship between data elements.
[0148] Also, various inventive concepts may be embodied as one or
more methods, of which an example has been provided. The acts
performed as part of the method may be ordered in any suitable way.
Accordingly, embodiments may be constructed in which acts are
performed in an order different than illustrated, which may include
performing some acts simultaneously, even though shown as
sequential acts in illustrative embodiments.
[0149] All definitions, as defined and used herein, should be
understood to control over dictionary definitions, definitions in
documents incorporated by reference, and/or ordinary meanings of
the defined terms.
[0150] The indefinite articles "a" and "an," as used herein in the
specification and in the claims, unless clearly indicated to the
contrary, should be understood to mean "at least one."
[0151] The phrase "and/or," as used herein in the specification and
in the claims, should be understood to mean "either or both" of the
elements so conjoined, i.e., elements that are conjunctively
present in some cases and disjunctively present in other cases.
Multiple elements listed with "and/or" should be construed in the
same fashion, i.e., "one or more" of the elements so conjoined.
Other elements may optionally be present other than the elements
specifically identified by the "and/or" clause, whether related or
unrelated to those elements specifically identified. Thus, as a
non-limiting example, a reference to "A and/or B", when used in
conjunction with open-ended language such as "comprising" can
refer, in one embodiment, to A only (optionally including elements
other than B); in another embodiment, to B only (optionally
including elements other than A); in yet another embodiment, to
both A and B (optionally including other elements); etc.
[0152] As used herein in the specification and in the claims, "or"
should be understood to have the same meaning as "and/or" as
defined above. For example, when separating items in a list, "or"
or "and/or" shall be interpreted as being inclusive, i.e., the
inclusion of at least one, but also including more than one, of a
number or list of elements, and, optionally, additional unlisted
items. Only terms clearly indicated to the contrary, such as "only
one of" or "exactly one of," or, when used in the claims,
"consisting of," will refer to the inclusion of exactly one element
of a number or list of elements. In general, the term "or" as used
herein shall only be interpreted as indicating exclusive
alternatives (i.e. "one or the other but not both") when preceded
by terms of exclusivity, such as "either," "one of," "only one of,"
or "exactly one of" "Consisting essentially of," when used in the
claims, shall have its ordinary meaning as used in the field of
patent law.
[0153] As used herein in the specification and in the claims, the
phrase "at least one," in reference to a list of one or more
elements, should be understood to mean at least one element
selected from any one or more of the elements in the list of
elements, but not necessarily including at least one of each and
every element specifically listed within the list of elements and
not excluding any combinations of elements in the list of elements.
This definition also allows that elements may optionally be present
other than the elements specifically identified within the list of
elements to which the phrase "at least one" refers, whether related
or unrelated to those elements specifically identified. Thus, as a
non-limiting example, "at least one of A and B" (or, equivalently,
"at least one of A or B," or, equivalently "at least one of A
and/or B") can refer, in one embodiment, to at least one,
optionally including more than one, A, with no B present (and
optionally including elements other than B); in another embodiment,
to at least one, optionally including more than one, B, with no A
present (and optionally including elements other than A); in yet
another embodiment, to at least one, optionally including more than
one, A, and at least one, optionally including more than one, B
(and optionally including other elements); etc.
[0154] In the claims, as well as in the specification above, all
transitional phrases such as "comprising," "including," "carrying,"
"having," "containing," "involving," "holding," "composed of," and
the like are to be understood to be open-ended, i.e., to mean
including but not limited to. Only the transitional phrases
"consisting of" and "consisting essentially of" shall be closed or
semi-closed transitional phrases, respectively, as set forth in the
United States Patent Office Manual of Patent Examining Procedures,
Section 2111.03.
* * * * *