U.S. patent application number 15/427000 was filed with the patent office on 2017-05-25 for lens precursor with features for the fabrication of an ophthalmic lens.
The applicant listed for this patent is Johnson & Johnson Vision Care, Inc.. Invention is credited to P. Mark Powell, Michael Widman, Christopher Wildsmith.
Application Number | 20170146822 15/427000 |
Document ID | / |
Family ID | 48875742 |
Filed Date | 2017-05-25 |
United States Patent
Application |
20170146822 |
Kind Code |
A1 |
Wildsmith; Christopher ; et
al. |
May 25, 2017 |
LENS PRECURSOR WITH FEATURES FOR THE FABRICATION OF AN OPHTHALMIC
LENS
Abstract
This invention provides for the fabrication of ophthalmic lenses
via the utilization of DMD shows and/or DMD files. More
specifically, the use of the DMD shows and/or DMD files to generate
lens precursor designs comprising described features to form part
of a substructure for the fluid reactive media portion of the lens
precursor and wherein the lens precursor can generate particular
ophthalmic lens designs in a free-form manner using methods
described herein.
Inventors: |
Wildsmith; Christopher;
(Jacksonville, FL) ; Widman; Michael;
(Jacksonville, FL) ; Powell; P. Mark;
(Jacksonville, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Johnson & Johnson Vision Care, Inc. |
Jacksonville |
FL |
US |
|
|
Family ID: |
48875742 |
Appl. No.: |
15/427000 |
Filed: |
February 7, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14110265 |
Oct 7, 2013 |
|
|
|
15427000 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02C 7/02 20130101; G02C
2202/04 20130101; G02C 7/024 20130101; A61F 2/1613 20130101; G02C
7/048 20130101; B29D 11/00134 20130101; B29C 64/129 20170801; B29D
11/00057 20130101; G02C 2202/08 20130101; B33Y 50/00 20141201; A61F
2240/005 20130101; B33Y 80/00 20141201; B29D 11/00153 20130101 |
International
Class: |
G02C 7/04 20060101
G02C007/04; A61F 2/16 20060101 A61F002/16; G02C 7/02 20060101
G02C007/02 |
Claims
1. A lens precursor form comprising: a concave, optical quality
first surface; an opposing second surface having a substantially
convex overall shape; wherein the first and second surfaces are
joined at a lens edge that defines the outer perimeter of the lens
precursor form; and a lens edge feature that is present on the
second surface and along or substantially adjacent to at least part
of the lens edge, said lens edge feature forming a projection
extending outwardly beyond said substantially convex overall shape
of said second surface; wherein the lens edge feature configured so
as to be capable of containing within the permitter of the lens
precursor form a fluent lens reactive media present on the second
surface of the lens precursor form.
2. The lens precursor form of claim 1 in which the lens edge
feature decreases in thickness from a maximum with increasing
distance from the lens edge, thereby forming an inwardly-facing
lens edge feature.
3. The lens precursor form of claim 2 in which the maximum
thickness of the lens edge feature is spaced from the lens
edge.
4. The lens precursor form of claim 3 in which the decrease in
thickness is continuous.
5. The lens precursor form of claim 4 wherein the inwardly-facing
lens edge feature is concave in a plane containing the axis of the
lens.
6. The lens precursor of claim 5 in which the lens edge feature is
continuous around the lens precursor form.
7. The lens precursor of claim 5 in which the lens edge feature is
present in discrete, non-continuous zones.
8. The lens precursor of claim 1 in which the height of the lens
edge feature is between 0.001 mm and 1 mm.
9. The lens precursor of claim 8 in which the lens edge feature is
higher in some discrete parts of the lens edge to control fluent
lens reactive media and provide a lens with a thicker edge in those
portions.
10. The lens precursor of claim 9 in which the radial extent of the
lens edge feature is from 0.001 mm to 2 mm.
11. A lens precursor form comprising: a concave, optical quality
first surface; an opposing second surface having a substantially
convex overall shape; wherein the first and second surfaces are
joined at a lens edge that defines the outer perimeter of the lens
precursor form; a centrally located optic zone; an outer edge
region surrounding said centrally located optic zone and extending
from said optical zone to said lens edge, and a moat feature that
is present within the outer edge region of the lens precursor form;
wherein the moat feature is defined by a substantially
discontinuous reduction in height of the second surface of the lens
precursor form as compared to substantially adjacent regions of the
second surface to thereby form a depression in the substantially
convex overall shape of the second surface.
12. The lens precursor form of claim 11 in which the moat feature
is defined by a region of the lens precursor form of a thickness
between zero and 0.2 mm.
13. A lens precursor form comprising: a concave, optical quality
first surface; an opposing second surface having a substantially
convex overall shape; wherein the first and second surfaces are
joined at a lens edge that defines an outer perimeter of the lens
precursor form; a centrally located optic zone; a plurality of lens
features present on the second surface and outside of the optic
zone, wherein said plurality of lens edge features each form a
projection extending outwardly and beyond said substantially convex
overall shape of said second surface, and each have a height
pre-determined height selected to control the flow of a fluent
reactive mixture across said second surface of said lens precursor
form and/or the shape to which the fluent reactive mixture settles
after a given period of time.
14. The lens precursor form of claim 13 wherein the plurality of
lens edge features are configured to control the desired height,
depth, angular width, length, shape, and/or angle, of minimal
energy surfaces of the fluent reactive mixture to produce desired
lens precursor geometries.
15. The lens precursor form of claim 14 wherein at least one of
said lens edge features comprises a section made up of two parts, a
lower shelf, and a higher shelf that abuts a relatively higher
thickness region of a stabilization zone feature.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/110,265 filed on Oct. 7, 2013, which claims
priority of PCT/US13/48572 filed Jun. 28, 2013, which claims
priority of U.S. Patent Application Ser. No. 61/665,973, filed on
Jun. 29, 2012.
FIELD OF USE
[0002] This invention describes a lens precursor device with one or
more lens precursor features that may be useful in the fabrication
of an ophthalmic lens. More specifically, the lens precursor is a
composite object comprising a lens precursor form and fluent lens
reactive media in contact with a lens precursor form, and said lens
precursor may be useful in the fabrication of ophthalmic lenses in
a free-form manner.
BACKGROUND OF THE INVENTION
[0003] Currently, ophthalmic lenses are often made by cast molding,
in which a reactive monomer material is deposited in a cavity
defined between optical surfaces of opposing mold parts. To prepare
a lens using such mold parts, an uncured hydrogel lens formulation
is placed between a plastic disposable front curve mold part and a
plastic disposable back curve mold part.
[0004] The front curve mold part and the back curve mold part are
typically formed via injection molding techniques wherein melted
plastic is forced into highly machined steel tooling with at least
one surface of optical quality.
[0005] The front curve and back curve mold parts are brought
together to shape the Lens according to desired lens parameters.
The lens formulation is subsequently cured, for example by exposure
to heat and light, thereby forming a lens. Following cure, the mold
parts are separated and the lens is removed from the mold parts for
hydration and packaging. However, the nature of cast molding
processes and equipment make it difficult to form custom lenses
specific to a particular patient's eye or a particular
application.
[0006] Consequently, in prior descriptions by the same inventive
entity, methods and apparatus for forming customized lenses via the
use of free-form techniques have been described. An important
aspect of these novel techniques is that a lens is produced in a
free-form manner, that is where one of two lens surfaces is formed
in a free-formed manner without the need of using cast molding,
lathing, or other tooling.
[0007] A free-formed surface and base may include fluent lens s
reactive media included in the free-formed surface at some point
during the formation. This combination results in a device
sometimes referred to as a lens precursor. Fixing radiation and
hydration treatments may typically be utilized to convert a lens
precursor into an ophthalmic lens.
[0008] Some of the free-formed lenses created in this manner may
need different methods and/or structural features for the control
of all or some of the fluent lens reactive media included in the
lens precursor. By controlling some of all of the fluent lens
reactive media, physical and/or optical parameters of a lens design
may be produced. The new methods and features are the subject
matter of the present invention.
SUMMARY OF THE INVENTION
[0009] The present invention is directed to a lens precursor and
methods of forming said lens precursor, for the fabrication of an
ophthalmic lens. More specifically, the lens precursor which may
comprise one or more lens precursor features used as part of a
substructure for at least portions of a fluent lens reactive media
portion of the lens precursor.
[0010] Some aspects of the present invention include different
methods and apparatus for iteration, for example, for the creation
of a DMD show and DMD file, for fabricating a lens precursor that
may comprise one or more lens precursor features. Generally,
applicable patient data and product data may be collected and
utilized to produce standard or custom product designs. A desired
product design or lens precursor design may comprise one or both of
lens precursor features and fluent lens reactive media
surfaces.
[0011] Lens designs, for a desired product may be generated from
lens precursor designs, thickness maps and associated files.
Separate thickness maps and associated files may be used as
stand-alone files, or combined with other thickness maps. For
example, DMD shows may be generated from lens precursor thickness
maps and associated files, lens design thickness maps and
associated files, DMD sub-sequence(s) or other methods, and
utilized in fabrication of a lens precursor.
[0012] Fabricated lens precursors may be compared to thickness maps
and associated files to determine conformance to desired product
designs. In cases where a fabricated product may not or does not
conform to desired requirements, DMD Iterative shows may be created
and modified in order to fabricate a lens precursor that may be
closer to a desired product design.
[0013] The following is a non-exhaustive list of exemplary
embodiments of the invention that are or may be claimed.
EMBODIMENT 1
[0014] An ophthalmic lens precursor comprising:
[0015] a lens precursor form comprising a crosslinkable media
comprising a photoabsorptive component;
[0016] a first surface and a second surface, wherein the first
surface comprises a portion of a first crosslink density degree at
least partially polymerized at or above a gel point;
[0017] a fluid second surface comprising a second crosslink density
degree of cure less than the gel point; and
[0018] wherein the first surface includes at least partially
polymerized topological features that may act as a lens precursor
form substructure and at least a portion of said second surface may
be incorporated into an ophthalmic lens.
EMBODIMENT 2
[0019] The ophthalmic lens precursor of Embodiment 1, wherein the
topological features include one or more of a lens edge feature, a
bump feature, a drain channel feature, a volumator feature, a lake
feature, and a stabilization zone feature.
EMBODIMENT 3
[0020] The ophthalmic lens precursor of Embodiment 2, further
comprising more than one of each one or more said topological
feature(s) included.
EMBODIMENT 4
[0021] The ophthalmic lens precursor of Embodiment 2, wherein each
included feature comprises one or more of a specified height,
length, shape and width.
EMBODIMENT 5
[0022] The ophthalmic lens precursor of Embodiment 4, wherein the
angular width of one or more of said included features may be
continuous throughout 360 degrees of the lens precursor.
EMBODIMENT 6
[0023] The ophthalmic lens precursor of Embodiment 4, wherein the
angular width of one or more of said included features is
non-continuous and generally present in discrete portions of said
first surface.
EMBODIMENT 7
[0024] The ophthalmic lens precursor of Embodiment 1, wherein said
first surface further comprises a moat feature in one or more
discrete portions.
EMBODIMENT 8
[0025] The ophthalmic lens precursor of Embodiment 1, additionally
comprising marks in one or both of said first surface and fluid
second surface.
EMBODIMENT 9
[0026] The ophthalmic lens precursor of Embodiment 1, wherein at
least a portion may be rotationally symmetrical.
EMBODIMENT 10
[0027] The ophthalmic lens precursor of Embodiment 1, wherein the
shape of the lens precursor may generally be circular.
EMBODIMENT 11
[0028] The ophthalmic lens precursor of Embodiment 1, wherein the
shape of the lens precursor may generally be oval shaped.
EMBODIMENT 12
[0029] The ophthalmic lens precursor of Embodiment 2, wherein one
or more of said features included may be described mathematically
by one or more of height, width, length, shape, and location of the
feature.
EMBODIMENT 13
[0030] The ophthalmic lens precursor of Embodiment 2, wherein one
or more of said features included may be obtained empirically from
one or more designs of lens precursor (s) or portions thereof.
EMBODIMENT 14
[0031] The ophthalmic lens precursor of Embodiment 1, wherein said
lens precursor may be further processed into an ophthalmic
lens.
EMBODIMENT 15
[0032] The ophthalmic lens precursor of Embodiment 14, wherein the
processing comprises stabilization of at least a portion of the
second fluid surface.
EMBODIMENT 16
[0033] The ophthalmic lens precursor of Embodiment 14, wherein the
processing further comprises fixing at least a portion of the
second fluid surface using actinic radiation to a crosslink density
degree at least partially polymerized at or above a gel point.
EMBODIMENT 17
[0034] The ophthalmic lens precursor of Embodiment 3, wherein more
than one bump features are used for the formation of at least a
portion of a bifocal lens.
EMBODIMENT 18
[0035] The ophthalmic lens precursor of Embodiment 3, wherein more
than one bump features are used for the formation of at least a
portion of a trifocal lens.
EMBODIMENT 19
[0036] The ophthalmic lens precursor of Embodiment 3, wherein more
than one bump features are used for the formation of at least a
portion of a lenslet array.
EMBODIMENT 20
[0037] The ophthalmic lens precursor of Embodiment 1, wherein the
lens precursor is formed in a free-form manner.
EMBODIMENT 21
[0038] The ophthalmic lens precursor of Embodiment 20, wherein the
free form manner includes voxel by voxel free forming methods.
EMBODIMENT 22
[0039] An ophthalmic lens precursor comprising:
[0040] a lens precursor form comprising a crosslinkable media
comprising a photoabsorptive component;
[0041] a first surface and a second surface, wherein the first
surface comprises a portion of a first crosslink density degree at
least partially polymerized at or above a gel point;
[0042] a fluid second surface comprising a second crosslink density
degree of cure less than the gel point; and
[0043] wherein the first surface includes at least partially
polymerized topological features that may be used to determine the
optical magnification of apparatus used to incorporate the lens
precursor into an ophthalmic lens.
EMBODIMENT 23
[0044] The ophthalmic lens precursor of Embodiment 22, wherein the
topological features include one or more of; a lens edge feature, a
bump feature, a drain channel feature, a volumator feature, a lake
feature, and a stabilization zone feature.
EMBODIMENT 24
[0045] The ophthalmic lens precursor of Embodiment 22, further
comprising one or more marks.
EMBODIMENT 25
[0046] The ophthalmic lens precursor of Embodiment 22, wherein the
one or more marks can be embedded into one or more of the
topological features.
EMBODIMENT 26
[0047] The ophthalmic lens precursor of Embodiment 22, wherein the
one or more Marks can be on the one or more of the topological
features.
EMBODIMENT 27
[0048] An ophthalmic lens precursor comprising:
[0049] a lens precursor form comprising a crosslinkable media
comprising a photoabsorptive component;
[0050] a first surface and a second surface, wherein the first
surface comprises a portion of a first crosslink density degree at
least partially polymerized at or above a gel point;
[0051] a fluid second surface comprising a second crosslink density
degree of cure less than the gel point; and
[0052] wherein the first surface includes at least partially
polymerized topological features that can be used to align the lens
precursor with one or more part of an apparatus used to incorporate
the lens precursor into an ophthalmic Lens.
EMBODIMENT 28
[0053] The ophthalmic lens precursor of Embodiment 27, wherein the
topological features include one or more of a lens edge feature, a
bump feature, a drain channel feature, a volumator feature, a lake
feature, and a stabilization zone feature.
EMBODIMENT 29
[0054] The ophthalmic lens precursor of Embodiment 27, further
comprising one or more marks.
EMBODIMENT 30
[0055] The ophthalmic lens precursor of Embodiment 27, wherein the
one or more marks can be embedded into one or more of the
topological features.
EMBODIMENT 31
[0056] The ophthalmic lens precursor of Embodiment 27, wherein the
one or more marks may be on the one or more of the topological
features.
EMBODIMENT 32
[0057] An ophthalmic lens precursor comprising:
[0058] a lens precursor form comprising a crosslinkable media
comprising a photoabsorptive component;
[0059] a first surface and a second surface, wherein the first
surface comprises a portion of a first crosslink density degree at
least partially polymerized at or above a gel point;
[0060] a fluid second surface comprising a second crosslink density
degree of cure less than the gel point; and
[0061] wherein the first surface includes at least partially
polymerized topological features that may be used as lens
identifiers upon incorporating the lens precursor into an
ophthalmic lens.
EMBODIMENT 33
[0062] The ophthalmic lens precursor of Embodiment 32, wherein the
lens identifiers are used as anti-counterfeiting marks.
BRIEF DESCRIPTION OF THE DRAWINGS
[0063] The foregoing and other features and advantages of the
invention will be apparent from the following, more particular
description of preferred embodiments of the invention, as
illustrated in the accompanying drawings.
[0064] FIG. 1A illustrates an exemplary side view cross-sectional
representation of a lens precursor form in flat space.
[0065] FIG. 1B illustrates an exemplary side view cross-sectional
representation of a lens precursor that comprises single lens
precursor features of multiple types in flat space.
[0066] FIG. 1C illustrates an exemplary side view cross-sectional
representation of a lens precursor that comprises single and
multiple types of lens precursor features in flat space.
[0067] FIG. 1D illustrates an exemplary side view cross-sectional
representation of a lens precursor that comprises single and
multiple types of lens precursor features, in addition to a moat
feature in flat space.
[0068] FIG. 1E illustrates a top view of an exemplary non-round
lens precursor that comprises single and multiple types of lens
precursor features, in addition to drain channel features.
[0069] FIG. 2 illustrates an example of a representation of an
image depicting formed marks on a lens.
[0070] FIG. 3 illustrates exemplary method steps that may be used
to implement some embodiments of the present invention.
[0071] FIG. 3A illustrates additional method steps that may also be
used to implement some embodiments of the present invention.
[0072] FIG. 3B illustrates yet additional method steps that may
also be used to implement some embodiments of the present
invention.
[0073] FIG. 4 illustrates an exemplary screen shot generated by
software program(s) depicting of a cross-sectional representation
of a target file in curved space.
[0074] FIG. 5 illustrates sample data generated by software
program(s) representing a portion of a thickness map.
[0075] FIG. 6 illustrates an exemplary screen shot generated by
software program(s) used to create and output desired optical and
mechanical features, which may be utilized to generate target
file.
[0076] FIG. 6a is a schematic drawing of the exemplary screen shot
of FIG. 6.
[0077] FIG. 7 illustrates a schematic diagram of an exemplary
processor that may be used for some parts of the present
invention.
[0078] FIG. 8A illustrates an exemplary top view and
cross-sectional representations of a Lens precursor in Curved
Space.
[0079] FIG. 8B illustrates an exemplary top view and side view
cross-sectional representations of a lens precursor in flat space,
depicting exaggerated thickness profiles.
[0080] FIG. 9A illustrates an exemplary representation of a
continuous surface single part design in top and side cross
sectional views, in both flat and curved space.
[0081] FIG. 9B illustrates an exemplary representation of a
non-continuous surface single part design in top and side cross
sectional views, in both flat and curved space.
[0082] FIG. 9C illustrates an exemplary representation of a
continuous surface multi-part design in top and side cross
sectional views in curved space.
[0083] FIG. 9D illustrates an exemplary representation of a
non-continuous surface multi-part design in top and side cross
sectional views in curved space.
[0084] FIG. 10 illustrates sample data generated by software
program(s) representing a portion of a DMD file.
[0085] FIG. 11 illustrates an exemplary lens formed using a DMD
file that may be implemented in some embodiments of the present
invention, rotated by 180.degree. around the y-axis and rotated
counter-clockwise by 45.degree. in an (x-y) plane.
[0086] FIG. 12 illustrates an exemplary lens formed using a DMD
file comprising circumferential drain channels.
[0087] FIG. 13A illustrates an exemplary lens formed using a DMD
file comprising circumferential drain channel instructions with a
changed edge curvature instruction section.
[0088] FIG. 13B illustrates a photograph of an exemplary
non-rotationally symmetric lens including a flattened segment of a
lens edge curvature and drain channels.
[0089] FIG. 14 illustrates an exemplary representation of two
cross-sections (45.degree. and 135.degree.) of a target lens
design, DMD show and measured lens precursor in flat space.
DETAILED DESCRIPTION OF THE INVENTION
[0090] The present invention provides for a lens precursor used to
fabricate ophthalmic lenses, said lens precursor device which may
comprise an array of topological features used to create a
substructure that may control properties/characteristics of a final
ophthalmic lens. In the following sections, detailed descriptions
of exemplary embodiments of the invention are given. The
description of both preferred and alternate embodiments though
detailed are exemplary embodiments only, and it is understood to
those skilled in the art that variations, modifications, and
alterations may be apparent. It is therefore to be understood that
said exemplary embodiments do not limit the broadness of the
aspects of the underlying invention. Method steps described herein
are listed in a logical sequence in this discussion; however, this
sequence in no way limits the order in which they may be
implemented unless specifically stated.
GLOSSARY
[0091] In the description directed to the presented invention,
various terms may be used for which the following definitions will
apply:
[0092] "Acceptance Criteria" as used herein, refers to specified
parameter ranges and threshold values in the system that can be
correlated to measured parameters and values of a fabricated
ophthalmic lens, lens precursor form or lens precursor, to
determine if the product is acceptable for its intended
purpose.
[0093] "Bump(s) features" as used herein, refer to lens precursor
protrusions of cured reactive media, which have been cured at or
above a gel point, thereby creating topological features. Bumps may
be formed, for example, by reducing the actinic radiation exposure
in one or more voxel location(s) by decreasing the exposure signal
given in a DMD instruction(s) at these locations. In an analogous
manner, bumps may also be formed by increasing the actinic
radiation exposure in one or more voxel location(s) by increasing
the exposure signal given in a DMD instruction(s) at these
locations. Bumps may be located in all of or portions of the
optical zone to assist in the formation of one or more lenslet
arrays upon curing in discrete portions therein. Alternately or
additionally, bumps may be formed in predetermined areas of the
optical zone for the formation of a bifocal lens.
[0094] "Catalog Item" as used herein, refers to a file, feature,
component, design, data, or descriptor that may be temporarily or
permanently stored, such as in libraries or databases, and can be
recalled for use.
[0095] "Curved Space" as used herein, refers to a coordinate
mapping space (e.g., Cartesian, polar, spherical, etc.) where the
curvature of a design has not been removed.
[0096] As an exemplary illustration of such, an ophthalmic lens may
be formed upon a back curve mold piece. This lens when inspected
may have a three dimensional shape fundamentally related to the
three dimensional shape of the mold piece. When cross sections are
depicted for this example lens in curved space the bottom of these
cross sections will be curved in a manner similar to the curve of
the mold piece. For better resolution of the lens front surface
shape, in some treatments of cross sectional depictions, the
thickness of the material above the back curve surface may be
magnified. In these cases, the cross section may still be described
as being presented in curved space.
[0097] "Custom Product" as used herein, refers to a product
including one or more parameters that may be available in other
than customary or standard products and/or settings. Custom product
parameters can allow for more precisely targeted sphere power,
cylinder power, and cylinder axis (e.g.,
-3.125D/-0.47D.times.18.degree.) than standard products. The
customized settings may also relate to base curves, diameters,
stabilization profiles, and thickness profiles based upon a
particular product offering and the intended use of the
product.
[0098] "Digital Core Break" as used herein, refers to a range of
products where select subsets of lens precursor features or control
parameters are kept identical. For example, in a lens "digital core
break" family offered with different power and sphere ranges, the
lens edge, stabilization zone features and volumator features may
be identical for all low power correction ranges.
[0099] "DMD control software" as used herein, refers to software
that organizes and utilizes DMD files and DMD shows as desired. For
example, the software may be used to enable fabrication or post
processing of lens precursors comprising lens precursor
features.
[0100] "DMD File" as used herein, refers to a collection of
instructional data points that may be used to activate mirrors on a
DMD, and thereby at least partially enable a lens or lens precursor
or lens precursor form or lens precursor feature(s) to be
fabricated. A DMD file can have various formats, with (x,y,th), and
(r, .theta., th) being the most common where, for example "x" and
"y" are Cartesian coordinate locations of DMD mirrors, "r" and
".theta." are polar coordinate locations of DMD mirrors, and "th"
represents thickness instructions controlling DMD mirror states.
DMD files may comprise data on a regularly or irregularly spaced
grid.
[0101] "DMD Iterative Show" as used herein, refers to a collection
of time based instructional data points that may be used to control
activation of mirrors on a DMD, and enable a lens, lens precursor,
lens precursor form, or lens precursor feature(s) to be fabricated.
A DMD iteration show may be used to fabricate a lens, lens
precursor, or lens precursor feature(s) that may be closer to a
design target than a lens, lens precursor, or lens precursor
feature(s) fabricated by a preceding DMD show and/or a DMD
sub-sequence. DMD iteration shows may comprise data on a regularly
or irregularly spaced grid.
[0102] "DMD Show" as used herein, refers to a time based sequenced
series of projection patterns emanating from a DMD device onto a
forming optic to fabricate a lens or lens precursor or lens
precursor form or lens precursor feature(s). A DMD show may be
sub-divided into a number of DMD sub-sequences. A DMD show may have
various formats, with (x,y,t), and (r, .theta., t) being the most
common where, for example "x" and "y" are Cartesian coordinate
locations of DMD mirrors, "r" and ".theta." are polar coordinate
locations of DMD mirrors, and "t" represents time instructions
controlling DMD mirror states. DMD shows may comprise data on a
regularly or irregularly spaced grid.
[0103] "DMD Sub-sequence" as used herein, refers to one or more
portions of a DMD show in which one or more of the projection
characteristics of the DMD show may be modified. Modifications to a
sequence may include one or more of a spatial pattern, a radiant
intensity level, a spectral region to project, a mirror
bit-splitting arrangement, direction of a projection pattern, and a
time order of a projection pattern.
[0104] "DMD" as used herein, a digital micro-mirror device is a
bistable spatial light modulator comprising of an array of movable
micro-mirrors functionally mounted over a CMOS SRAM. Each mirror is
independently controlled by loading data into the memory cell below
the mirror to steer reflected light, spatially mapping a pixel of
video data to a pixel on a display. The data electrostatically
controls the mirror's tilt angle in a binary fashion, where the
mirror states are either +X degrees (on) or -X degrees (off). For
current devices, X can be either 10 degrees or 12 degrees
(nominal). Light reflected by the on mirrors then is passed through
a projection lens and onto a screen. Light is reflected off to
create a dark field, and defines the black-level floor for the
image. Images are created by gray-scale modulation between on and
off levels at a rate fast enough to be integrated by the observer.
The DMD (digital micro-mirror device) is sometimes DLP projection
systems.
[0105] "Drain Channel" as used herein, refers to a lens precursor
topological feature that may be generated by either one or both
reduced and increased exposure of voxel locations to actinic
radiation by control instruction(s) in an analogous fashion to that
discussed in the definition for bump features. The topological
feature may be of a shape that can enable fluent lens reactive
media to do one or more of the following: flow across, away from,
and settle on, all or at least a portion of a polymerized lens
precursor, lens precursor form, or another other lens precursor
feature(s). The topographical feature may include, for example
continuous or discrete segmented elongate depressions in portions
of the gelled portion of the lens precursor. Drain channels may be
placed side by side and configured to enable the flow of fluent
lens reactive media across the lens precursor form.
[0106] "Fabrication Process Conditions" as used herein, refers to
settings, conditions, methods, equipment, and processes used in
fabrication of one or more of a lens precursor, a lens precursor
form, and a lens.
[0107] "Flat Space" as used herein, refers to coordinate mapping
space, (e.g., Cartesian, polar, spherical), where curvature of a
design being considered has been removed/flattened. As an
illustration of such a depiction, an example ophthalmic lens may be
formed upon a back curve mold piece. This example lens when
inspected may have a three dimensional shape fundamentally related
to the three dimensional shape of the mold piece. When cross
sections are depicted for this example lens in flat space the
bottom of these cross sections may be "removed/flattened" which
results in the curved back curve shape being represented by a flat
line. For better resolution of the lens front surface shape, in
some treatments of cross sectional depictions, the thickness of the
material above the now "removed/flattened" back curve surface may
be magnified. In these cases, the cross section may still be
described as being presented in flat space.
[0108] "Fluent Lens Reactive Media" as used herein and sometimes
referred to as "Fluent Lens reactive mixture" or "Lens forming
Mixture" means a reactive mixture, prepolymer mixture or monomer
mixture that is flowable in either its native form, reacted form,
or partially reacted form and may be formed upon further processing
into a part of an ophthalmic lens. Further, the monomer mixture or
prepolymer material may be cured and crosslinked or crosslinked.
Lens forming mixtures may include one or more additives such as: UV
blockers, tints, photoinitiators or catalysts, and other additives
one might desire in ophthalmic lenses such as, contact or
intraocular lenses.
[0109] "Free-Form" and "Free-Formed" as used herein refer to a
surface that is formed by crosslinking of a reactive mixture via
exposure to actinic radiation on a voxel by voxel basis, with or
without a fluent media layer, and is not shaped according to a cast
mold, lathe, or laser ablation. Detailed description of free-form
methods and apparatus are disclosed in U.S. patent application Ser.
No. 12/194,981 filed Aug. 20, 2008, in U.S. patent application Ser.
No. 12/195,132 filed Aug. 20, 2008, and in EP-A-2,178,695,
EP-A-2,228,202, EP-A-2,228,201, EP-A-2,178,694 and
EP-A-2,391,500.
[0110] "High Order Optical Aberration(s)" as used herein, refers to
distortion(s) in an image formed by an optical system due to
optical deviations. More specifically, in an eye, it can include
one or more symptoms known in the field of vision correction as
spherical aberration(s), trefoil, coma, and pentafoil.
[0111] "Iterative Fabrication Process" as used herein, refers to a
process of exercising an iterative loop by using one or both of DMD
Iterative show(s) and modifications to fabrication process
conditions in order to fabricate a lens, lens precursor form, or
lens precursor that may be closer to a desired thickness map/target
design than its predecessor.
[0112] "Iterative Loop" as used herein, refers to one, or a series
of process steps, components and/or conditions that may enable a
lens or lens precursor, lens precursor form, or lens precursor
feature(s) fabrication such that each time through a loop, a lens,
lens precursor, lens precursor form, or lens precursor feature(s)
may be more conforming to a desired target than its
predecessor.
[0113] "Lake Feature" as used herein, refers to a lens precursor
topological feature that is included in some lens precursor
designs. A lake feature can be generated by either one or both
reduced and increased exposure of voxel locations to actinic
radiation by control with DMD instruction(s) in an analogous
fashion to that discussed in the definition for bump features. A
lake feature sometimes referred to as a "Lake Topological feature"
may include a depression in a portion of the crosslinked gelled
portion of the lens precursor to contain a greater volume of fluent
lens reactive media in relation to adjacent areas.
[0114] "Lens Design" as used herein, refers to form, function or
both of a desired lens, which if fabricated, may provide functional
characteristics comprising optical power correction, acceptable
lens fit (e.g., corneal coverage and movement), and acceptable lens
rotation stability. lens designs may be represented for example, in
either a hydrated or un-hydrated state, in flat or curved space, in
2-dimensional or 3-dimensional space, and by a method including but
not limited to, geometric drawings, power profile, shape, features,
and thicknesses. Lens designs may include data associated with a
regularly or irregularly spaced grid.
[0115] "Lens Edge" as used herein, refers to a topological feature
capable of providing a defined edge around at least a portion of
the perimeter of a lens precursor, lens precursor form, or a lens
that may include fluent lens reactive media. A lens edge
topological feature may be either continuous around a lens
precursor or a lens, or may be present in discrete, non-continuous
zones. Such a lens edge may comprises a fence structure that is
configured contain a fluent lens reactive media present within the
perimeter of the lens precursor form.
[0116] "Lens precursor feature," also referred to as a "feature" or
a "topological feature," as used herein, refers to a non-fluent
part of a substructure of a lens precursor form, which may act as
an infrastructure for a lens precursor. Lens precursor features may
be defined empirically or described mathematically by control
parameters including height, angular width, length, shape and
location. features may be generated via DMD show instructions using
controlled vectors of actinic radiation and may be incorporated
into an ophthalmic lens upon further processing. Examples of lens
precursor features may comprise one or more of: a lens edge, a
stabilization zone feature, a volumator feature, an optic zone, a
moat feature, a drain channel feature, a lake feature, and bump
feature.
[0117] "Lens precursor Form" as used herein, refers to a non-fluent
object with at least one optical quality surface, which may be
consistent with being incorporated upon further processing into an
ophthalmic lens.
[0118] "Lens precursor" as used herein, means a composite object
comprising of a lens precursor form and fluent lens reactive media
in contact with a lens precursor form that may be rotationally
symmetrical or non-rotationally symmetrical. For example, fluent
lens reactive media may be formed in the course of producing a lens
precursor form within a volume of reactive mixture. Separating a
lens precursor form and fluent lens reactive media from a volume of
reactive mixture used to produce a lens precursor form may generate
a lens precursor. Additionally, a lens precursor may be converted
to a different entity by either the removal of an amount of fluent
lens reactive media or the conversion of an amount of fluent lens
reactive media into non-fluent incorporated material.
[0119] "Lens" as used herein, refers to any ophthalmic device that
resides in or on the eye. These devices may provide optical
correction or may be cosmetic. For example, the term lens may refer
to a contact lens, intraocular lens, overlay lens, ocular insert,
optical insert or other similar device through which vision is
corrected or modified, or through which eye physiology is
cosmetically enhanced (e.g., iris color) without impeding vision.
Lenses of the invention may be soft contact lenses made from
silicone elastomers or hydrogels, which include but are not limited
to silicone hydrogels, and fluorohydrogels.
[0120] "Low Order Optical Aberration(s)" as used herein, refers to
a distortion(s) in an image formed by an optical system due to
optical deviations. More specifically, in an eye, it may include
correcting one or more symptoms known in the field of vision
correction by adjusting one or more of sphere power, cylinder
power, and cylinder axis.
[0121] "Minimal Energy Surface" as used herein and sometimes
referred to as "MES", refers to a surface created by fluent lens
reactive media formed over lens precursor features, which may be in
a minimum energy state. Minimal energy surfaces may be smooth and
continuous surfaces or smooth discrete segments of lens precursor
features.
[0122] "Moat" as used herein, refers to a lens precursor
topological feature that may be formed using fixed values in DMD
show in one or more areas and is lower in height than surrounding
features. Except that the feature may be defined by using fixed
values in the DMD show, the general procedure for forming a moat or
"Moat feature" may be performed in an analogous fashion to that
described in the definition for Bump features. Additionally, a moat
may be extended into or be a part of another feature, such as, a
volumator. The "Moat" may be defined by a substantially
discontinuous reduction in height of the lens precursor form and/or
defined by a region of the lens precursor form of substantially
zero or zero thickness.
[0123] "Multi-Part Design" as used herein, refers to a design where
required information to reconstruct a desired profile is included
in two or more files. Additionally, the two or more files may
include one or more discrete, non-contiguous and non-continuous
surfaces. Multi-part designs may include feature separation in an
(x-y) plane which in a flat space depiction of an exemplary lens
cross section may be a plane that "heads into the paper," and may
also include separation in an (x-z) plane which in a similar flat
space depiction of an exemplary lens cross section may be
represented by the plane of the paper itself.
[0124] "Optic Zone" as used herein, refers to the region of the
lens or lens precursor in which a wearer of the lens sees after the
lens is formed.
[0125] "Optical Aberration" as used herein, refers to a distortion
in an image formed by an optical system that may include either one
or both of low order optical aberrations and high order optical
aberrations.
[0126] "Product" as used herein, refers to a desired lens or lens
precursor. The product may be either a "standard product" or a
"custom product".
[0127] "Single Part Design" as used herein, refers to a design
where required information of a desired profile may be represented
in one file. Single part designs may result in a lens precursor
form, which may have either a continuous surface, or a
non-continuous surface.
[0128] "Stabilization Zone" as used herein, refers to a
topographical feature that assists in keeping non-rotationally
symmetric contact lenses correctly oriented on an eye and may be
found inboard of an edge feature and outboard of one or both of an
optical-power region and an optic zone.
[0129] "Standard Product" as used herein, refers to a product with
limited product parameter availability, such as those currently
offered with specified settings that vary in discrete steps. For
example, standard products could define a family of products where
sphere power parameters may only be available in 0.25D steps (e.g.,
-3.00D, 3.25D, -3.50D, etc.); cylinder power parameters may only be
available in 0.50D steps (e.g., -0.75D, -1.25D, -1.75D, etc.); and
cylinder axis parameters may only be available in 10.degree. steps
(e.g., 10.degree., 20.degree., 30.degree., etc.). Other standard
product parameters and features offered in discrete steps include
but are not limited to base curve radii, diameter, stabilization
profiles and thickness profiles.
[0130] "Substrate" as used herein, refers to a physical entity upon
which other entities may be placed or formed.
[0131] "Substructure" as used herein, refers to topological
features or parameters that are capable of supporting and sometimes
influencing at least a portion of fluent lens reactive media in a
lens precursor. The substructure may include one or both the
substrate and one or more lens precursor features included for the
particular lens design. The control of the fluent lens reactive
media may include, for example, regulating the amount of lens
reactive media in the lens precursor in one or more sections and
influencing the resulting optical properties of the free-formed
ophthalmic lens.
[0132] "Target File" as used herein and sometimes referred to as
"Target Lens Design," refer to data that represents a lens design,
a thickness map, a lens precursor design, a lens precursor feature
design, or combinations of the above. A target file may be
represented in either a hydrated or un-hydrated state, in flat or
curved Space, in 2-dimensional or 3-dimensional space, and by
methods including but not limited to, geometric drawings, power
profile, shape, features, thicknesses etc. Target files may contain
data associated with a regularly or irregularly spaced grid.
[0133] "Thickness Map" as used herein, refers to a 2-dimensional or
3-dimensional thickness profile representation of a desired
product, or lens precursor. Thickness maps may either be in one or
both of flat space coordinate space and curved space coordinate
space, and may contain data associated with a regularly or
irregularly spaced grid.
[0134] "Volumator" as used herein, refers to a feature that
controls the flow of the fluid reactive mixture in relation to an
outer edge of the lens precursor, or another feature or region of
the lens precursor. A volumator may allow one or more of the
following: desired heights, depths, angular widths, lengths,
shapes, and angles, etc., of minimal energy surfaces to produce
desired lens precursor geometries. Parameters defining a volumator
are in many cases selected based at least in part upon parameters
defining adjacent lens features and a desired lens shape.
[0135] "Voxel" as used herein, also referred to as "Actinic
Radiation Voxel" is a volume element, representing a value on a
regular or irregular grid in 3-dimensional space. A voxel may be
viewed as a three dimensional pixel, however, wherein a pixel
represents 2D image data a voxel includes a third dimension. In
addition, wherein voxels are frequently used in the visualization
and analysis of medical and scientific data, in the present
invention, a voxel is used to define the boundaries of an amount of
actinic radiation reaching a particular volume of reactive mixture,
thereby controlling the rate of crosslinking or polymerization of
that specific volume of reactive mixture. By way of example, voxels
are considered in the present invention as existing in a single
layer conformal to a 2-D mold surface wherein the actinic radiation
may be directed normal to the 2-D surface and in a common axial
dimension of each voxel. As an example, specific volume of reactive
mixture may be crosslinked or polymerized according to
768.times.768 voxels.
[0136] The present invention includes methods and apparatus for
forming a lens precursor comprising topological features as part of
a substructure of a lens precursor form/lens precursor. The
substructure may function to control of at least a portion of the
non-polymerized or partially polymerized fluent reactive media
portion of the lens precursor. Said lens precursor which may be
further processed into an ophthalmic lens.
Lens Precursor Features
[0137] Many types of ophthalmic contact lenses can be much more
complex ophthalmic lenses than it would be expected from their
appearance and as currently utilized. In some types of ophthalmic
lenses, underlying features may be essential to allow for peak
performance, comfort, and different functionality. In the
description of the inventive art herein, a number of such features
that are relevant to the art of fabricating ophthalmic lenses in a
free-form manner are described. After a description of some of the
novel aspects and the nature of these features, a description will
then be made that portrays how, in exemplary embodiments of the
invention, the features may be formed, act, and interact with each
other and the use of an exemplary free-form process that can allow
for desired aspects of a desired product or a target lens design.
This then provides a basis for describing some exemplary
methodology consistent with the inventive art herein.
[0138] Proceeding to FIGS. 1A and 1B, it may be apparent that cross
sectional depictions demonstrate the level of complexity that the
collection of features may define. The two figures depict a
fundamental aspect of the free-form art; namely, the lens
precursor. A lens precursor, as its glossary definition provides
the full definition for, is a combination of a polymerized
region(s) above a gel point in combination with non-polymerized or
partially polymerized regions below a gel point fluent lens
reactive media. The non-polymerized or partially polymerized below
a gel point fluent lens reactive media may provide the framework
for generating ophthalmic lens products with high optical
performance.
[0139] Flowing across a gelled substructure, at least a portion of
the fluent lens reactive media may flow to a particular state, for
example, a minimum energy surface state. This may produce a much
smoother surface that can allow for the creation of desirable
optically active regions but also can add to the complexity of
generating the overall lens product. For example, using novel
free-form design and production technology may enable the lens
product using aspects of fluent lens reactive media in conjuncture
with the substructure.
[0140] Referring back to FIG. 1A and FIG. 1B, FIG. 1A depicts a
gelled substructure cross section of an exemplary lens precursor
alone in flat space, sometimes referred to as the lens precursor
form. FIG. 1B depicts the same substructure, also in flat space,
along with a fluent lens reactive media layer upon the gelled
substructure.
[0141] In FIG. 1A, a side view cross-sectional representation of an
exemplary lens precursor form 100A is depicted in flat space where
the natural three-dimensional curvature of ophthalmic lens devices
is removed so that the thickness of the features themselves may be
clearly envisioned. The exemplary cross section includes a
collection of different lens precursor features. The lens precursor
form 100A may comprise one continuous lens edge 110A. This feature
may be described as continuous to define the fact that the lens
edge abuts and may connect to its neighboring features as shown as
item 115A in the cross sectional FIG. 1A. It may also help in
understanding the nature of this lens precursor edge feature, as in
some implementations, it may exist all around the periphery as
depicted in FIG. 1E item 110E.
[0142] Continuing with features demonstrated in FIG. 1A, at 115A a
continuous stabilization zone feature is depicted. This
stabilization zone feature when viewed in a plan view, FIG. 1E is
represented as items 115E on either side of the exemplary lens. As
previously mentioned, these types of lens precursor features may be
important in providing different functions. In particular, the
stabilization zone features may be important, for example, in
providing the function of locating the ophthalmic lens in a correct
location and/or orientation when it is on the eye of a user. In
some stabilization zone features, the feature may assume a shape
that has a larger thickness to perform its function, as shown in
the left side of FIG. 1A, item 115 A. Additionally, it may be
apparent from observing the exemplary representation which includes
fluent lens reactive media 135B in FIG. 1B, that fluent lens
reactive media in the region of feature 115 B may have particular
effect due to the topological aspects of the regionally thicker
nature of the stabilization zone feature, 115B.
[0143] Continuing across the exemplary cross section, FIG. 1A, at
120A an exemplary continuous volumator feature is depicted. As
described in further detail in subsequent sections, the shape of
this feature may include various implications. In the location of
this cross section, this feature 120A on the left side of the cross
section may be made up of two parts, a lower shelf, and a second
higher shelf that abuts the high thickness region of the
stabilization zone feature 115A on the left side of the cross
section. Alternately, on the right side of the cross section where
the stabilization zone feature 115B may not be so thick, the
volumator feature 120B may be a simple shelf at about the same
thickness as the Stabilization Zone. By the nature of some fluent
lens reactive materials, this exemplary difference in the cross
section of the volumator next to features of different heights can
enable desired resulting properties of the end product. For
example, the volumator can require having more "volume" potential
for fluent media to flow into next to relatively thick topological
features.
[0144] At 125A, an optic zone is depicted. The optic zone or a
portion thereof may reside on an ophthalmic lens user's eye in
front of the portions of the eye where light may pass into the eye
body. Moreover, the combination of the optic zone substructure 125B
and fluent media 135B in the optic zone may create combined
thickness profiles that may result in the desired optical
properties of the entire optic zone.
[0145] Yet another feature characteristic can be a lens edge. A
lens edge may be present on an outer edge of a lens precursor and
may be the same or different heights or angular widths all of the
way around a lens precursor. The lens edge may be continuous around
a lens precursor, or may be present in discrete, non-continuous
zones. The lens edge may act like a fence structure to provide a
well-defined edge that may contain fluent lens reactive media and
can keep it from flowing or control the flow over an edge of a lens
precursor during various stages during the fabrication of a
lens.
[0146] In FIG. 1A, the height of a lens edge 110A on a lens
precursor may range from 0.001 mm to 1.000 mm to provide at least
portions of the desired substructure, said substructure that may be
capable of influencing the fluent reactive media near the edge of a
lens precursor. The definition of the regional shape or height
profile may be achieved by a variety of methods including the
increasing of intensity, wavelength, or time of actinic radiation
exposure of monomer mixture in a particular location to result in
higher regions and conversely the opposite relative adjustment to
result in lower regions. These higher regions may function, for
example, to have a higher lens edge in some discrete parts of the
defining edge to control the fluid lens reactive media and
accordingly, provide a lens that comprises a thicker lens edge in
those portions.
[0147] The lengths of the lens edge may also differ in different
designs and may include lengths that may range from 0.001 mm to
2.00 mm. The lens edge may be continuous around the perimeter or be
present in segmented sections as per the target design.
Accordingly, the length of the edge feature can form a minimal
energy surface for the fluent lens reactive mixture.
[0148] At 115A, a continuous stabilization zone topological feature
is depicted. stabilization zone topological features may be present
in a lens precursor accordingly and include height or thickness
ranges of about 0.050 mm to 1.000 mm, and ranges of lengths of
about 0.001 mm to 4.500 mm. These stabilization zones may also
assume a great diversity of design aspects and may be continuous,
segmented, or non-continuous. For example, one stabilization ring
can be present which includes two proportionally large protruding
regions for stabilization functionality.
[0149] At 120A, a volumator topological feature is depicted. As
mentioned, the volumator feature may aid in the controlled flow of
fluid reactive mixture between one or more regions of the lens
precursor. Consequently, when the feature may be defined with a
locally emptier volume of gelled material, the flow of fluent media
may be characterized as being "controlled." Where there is
controlled flow, a greater volume of fluid lens reactive mixture
may be present therein; which may thereby allow for a larger volume
of fluid lens reactive mixture to be subsequently cured in those
areas of the lens precursor.
[0150] The volumator may be continuous around a perimeter or
non-continuous. The height or thickness of the volumator may
include portions with ranges from 0.001 mm to 1.000 mm and ranges
of lengths from 0.001 mm to 4.500 mm.
[0151] Referring again to FIG. 1B, a cross-sectional representation
of a lens precursor 100B that includes single lens precursor
features of multiple types and heights 105B are illustrated. The
lens precursor may include a single, continuous lens edge 110B, a
single, stabilization zone feature 115B, a single, continuous
volumator feature 120B, a single, continuous optic zone 125B, a
minimum energy surface 130B, and fluent lens reactive media 135B.
As depicted, the minimum energy surface 130B may be created by
reactive media polymerized at or above a gel point to form a lens
precursor with features that may act individually, or with each
other, to create a minimum energy surface for fluid lens reactive
media to sit on and be at a lower and sometimes at a minimal
surface energy state 1306. As depicted, minimal energy surfaces can
be smooth and continuous surfaces. However, it is possible to
implement the invention so that the minimal energy surfaces may be
in smooth discrete segments.
[0152] Accordingly, the present invention leverages the concept of
a minimal energy surface which may derive its shape as a result of
the ways in which fluent lens reactive media may sit and flow over
a substructure of a lens precursor form. Consequently, the flow and
amount of fluent lens reactive media that sits on or adhere to a
particular portion of a lens precursor form may be influenced by
the shape and topology of that lens precursor form. For example,
lens precursor features in the lens precursor form may not in their
own right create a smooth and continuous profile; however, a
resulting lens precursor may indeed be smooth and continuous when
viewed as the combination, item 105B, of the lens precursor form
and the fluent lens reactive media. This concept will be explained
further in subsequent sections herein.
[0153] Referring now to FIG. 1C, a cross-sectional representation
of another exemplary lens precursor 100C that includes different
types of lens precursor features 105C is illustrated. A
characteristic difference in this lens precursor design; however,
is that some of the features depicted may occur one time in the
design whereas other features may occur numerous times.
[0154] In the exemplary lens precursor 100C, the lens precursor
includes a single lens edge 110C, multiple stabilization zone
features 115C, multiple volumator features 120C, a single optic
zone 125C, a minimum energy surface 130C, and fluent lens reactive
media 135C. In some cases like the multiple versions of the
stabilization zone features, a single cross sectional depiction may
demonstrate at least two different versions of the lens precursor
feature, as for example, the volumator that appears to the left of
the leftmost stabilization zone feature depicted and the volumator
that appears to the right of that stabilization zone feature.
[0155] Multiple versions of features may be more apparent by
observing a plan representation of the device. In a more general
sense, a great diversity of embodiments of lens precursor designs
may exist that may derive from multiple occurrences of certain lens
precursor features. (The multiplicity of the specified features is
not limited to stabilization zones and volumators as the design may
include more than one of any of the above-mentioned features
depending on the target lens design of a particular product).
[0156] Referring now to FIG. 1D, a cross-sectional representation
of a lens precursor 100D that includes different types of lens
precursor features 105D occurring in single and multiple instances
per design and in addition to a moat feature 140D is illustrated.
In the present exemplary lens precursor 100D, a single lens edge
110D, multiple stabilization zone features 115D, multiple volumator
features 120D, a single moat feature 140D, multiple Optic Zones
125D, a minimum energy surface 130D, and fluent lens reactive media
135D are included. It is apparent to one skilled in the art, that
very complex ophthalmic lenses may be designed when individual lens
precursor features are combined and organized together to enable
target lens designs.
[0157] As depicted in FIG. 1D, a moat feature 140D represents
another type of lens precursor feature or topological feature that
can be included in designs. Similar in some manners to volumators,
moat features may be significantly lower in height than surrounding
features and may typically be formed. A moat may be extended into
or be a part of another feature, such as, a volumator.
Additionally, a moat may consist of a section that is below a gel
point in the lens precursor (and hence be defined in the portion of
the lens precursor that has reached the gel point).
[0158] Referring now to FIG. 1E, a top view representation of the
structure of an exemplary non-round lens precursor 105E that
includes single and multiple different types of lens precursor
features is depicted. Also visible in a top view but not discussed
as yet in the prior cross section related discussion, another type
of lens precursor feature called a drain channel 145E. The drain
channel features 145E may help reduce a volume of one or more
reduced gelled feature(s). Thus, the nature of the shape of the
drain channel may be such as to draw additional volumes of fluent
lens reactive mixture away from a particular region.
[0159] In the present, exemplary lens precursor 100E, a listing of
all the lens precursor features that may be seen from a top view
perspective includes drain channel features 145E, a single lens
edge 110E, multiple stabilization zone features 115E, multiple
volumator features 120E, and a single optic zone 125E.
[0160] The drain channel feature(s) 145E may be generated by
reducing the actinic radiation exposure in one or more voxel
location(s) by decreasing the exposure signal given in a DMD
instruction(s) at these locations. In an analogous manner, the
drain channel feature(s) may also be formed by increasing the
actinic radiation exposure in one or more voxel location(s) by
increasing the exposure signal given in a DMD instruction(s) at
these locations. In either case, the relative change in actinic
radiation exposure would create relative depressions that may occur
in the straight line type shapes similar to those of items 145E.
Furthermore, from a more general perspective, the drain channel
feature(s) may be of a shape that may enable fluent lens reactive
media to do one or more of the following: flow across, away from,
and settle on, all or at least a portion of a polymerized lens
precursor, lens precursor form, or another other lens precursor
feature(s). The drain channel topographical feature may include,
for example continuous or discrete segmented depressions in
portions of the gelled portion of the lens precursor.
Varied Characteristics of Lens Precursor Features
[0161] An additional aspect of the present invention comes from the
changes in form and function of ophthalmic lenses that may derive
from variations of one or more parameters of one or more lens
precursor features, for example, including varying one or more of
height, depth, angular widths, length, shape, and location.
Furthermore, the same variations in ophthalmic lens characteristics
due to variations in the parameters of lens precursor features also
create additional inventive art when they are combined in various
manners described herein.
[0162] Lens precursor features may be parametrically controlled
based on empirically defined relationships between these features
and desired lens characteristics, and these features may be
mathematically or empirically related to other lens precursor
features. For example, the design of a volumator feature may be
empirically linked to stabilization zone features to create smooth
and continuous surfaces relationships between them and therefore
assist in the determination of appropriate design choices that
incorporate these features in combinations and thereby end up with
the designed lens properties or function.
[0163] More importantly, other uses of the lens precursor features
may include, for example, influencing the flow of at some portions
of the fluent lens reactive media. Lens precursor features may
additionally be utilized for alignment and calibration purposes of
lens precursor fabrication.
[0164] Additional features may include marks which may be defined
into the gelled material and may become visible under inspection.
These marks may be then used in the fabrication process. For
example, substrates used in a free-form process may need to be
precisely centered in order to manufacture a desired lens
precursor, ophthalmic lens, or lens precursor features. The marks
defined into gelled material by the imaging system may be viewed
and compared to a targeted location(s) of the marks to then provide
alignment of the imaging system to the physical Substrate.
[0165] Lens precursor features may also be used to determine
optical magnification of free-form equipment. In a non-limiting
exemplary sense, by defining marks into the gelled material, for
example by using the imaging system and a particular target size,
then the marks may be subsequently measured to then provide the
resulting measured mark versus the imaged size to allow for the
determination and control of the magnification of the system. This
may be important with free-form manufacturing processes, as optical
magnification values may be required to ensure that one or more of
height, depth, width, length, shape, and location of features may
be fabricated as desired.
[0166] Optical magnification together with the marks may be useful
in determining and controlling an accurate positioning of the
substrate. For example, where lens precursor features may be used
for one or more of alignment, calibration, and optical
magnification determination, Marks may be measured via imaging
techniques, including wavefront technology.
[0167] The marks can include fiducial marks, also referred to as
orientation marks, which can be defined by lens precursor features
and parameters, and fabricated on lens precursors using free-form
methods. Fiducial marks may be used to determine one or more of;
on-eye lens location, centration, rotation, and movement.
Furthermore, imaging techniques and wavefront technology can
additionally make use to help determine one or more of location,
size, and shape of fiducial marks. An image depicting fiducial mark
detection on a lens on eye is illustrated in FIG. 2.
[0168] The mark features may even be formed into characters, such
as, in a non-limiting sense letters or numbers to convey
information. Other types of mark features conveying information may
derive from bar codes or other optically recognizable character
features. There may be numerous uses for character type features to
be formed into an ophthalmic lens precursor such as for example,
the creation of anti-counterfeiting features and product lens
identifications.
[0169] Additional functionality of lens precursor features may
include creating optic zones that result in topology that is both
of optical grade and at the same time provides corrective aspects
to vision of a user, as this is a major purpose of free-form
processes. By controlling the topology of gelled surfaces, for
example on a pixel-by-pixel basis, and by controlling the
characteristics of the fluent media over these gelled surfaces and
neighboring lens precursor features, a particular desired
corrective surface can be formed. However, it will be apparent to
one skilled in the art that flat surfaces of gelled material with
various shapes including for example round features may, in some
cases and with certain fluent media characteristics, form small
nearly spherical shapes of fluent media that when fixed with
actinic radiation form a feature called a lenslet. If these
features, in isolated form or in an array form occur on the lens
precursor they may have the effect of modifying the optical power
of the regions they cover.
Interactions Between Two or More Lens Precursor Features
[0170] As mentioned in previous sections, the dynamics of flow of
fluent lens reactive media may be a complex function of the fluent
media itself, and numerous other factors, including the shape and
topology of features surrounding a particular region. In another
related aspect of the present invention, the effect of neighboring
features may be exploited by adjusting the control parameters of
these neighboring lens precursor features. As well, since these
adjusted parameters may affect the fluid dynamics of the fluent
lens reactive media, the surface that results after the fixation of
the fluent media may also be affected by these changes in the
design parameters of lens precursor features. As a specific
non-limiting example, the angle that fluent lens reactive media may
create as it bridges from an optic zone to a stabilization zone
feature may be controlled by modifying the control parameters of a
volumator feature and/or the control parameters of an optic
zone.
[0171] If the height of the volumator is decreased in its location
between the neighboring stabilization zone feature and the
neighboring optic zone, the change in form which the fluent lens
reactive media takes spanning between these two features and above
the adjusted volumator may be considered and accounted for in the
design. This is but one exemplary type change where a lens
precursor feature change may affect the fluent media above and
around other neighboring features and there may be other types of
changes which can cause a particular desired effect.
[0172] Another non-limiting example may be described with reference
to an astigmatic optic zone where the thickness in the 0 degree
plane is different to the thickness in the 90 degree plane. The
optic edge may, for example, be 100 microns thick in the 0 degree
plane, and 150 microns thick in the 90 degree plane. In the lens
precursor form, as has already been described, such an optic zone
may be surrounded by a volumator feature outside of which there may
be one or more stabilization zones, for example 400 microns in
height. If the stabilization zone and the highest point (150
microns) on the optic zone are angularly aligned, fluent lens
reactive media will form a bridge from the 400 microns high
stabilization zones to the highest point on the optic zone over the
volumator feature. If the same geometry and features are used, but
the optic zone is now rotated by 90 degrees and the volumator and
stabilization zones stay in the same orientation as before, the
fluent lens reactive media will now bridge differently from the
stabilization zones at a height of 400 microns to the optic zone
edge that is now 100 microns high. Thus, the angle that fluent lens
reactive media may create as it bridges from an astigmatic optic
zone to a stabilization zone feature may be controlled by modifying
the control parameters (angular alignment) of the stabilization
zone or the optic zone.
[0173] Yet another example would involve changing the location of
the drain channel features relative to other features, so that the
effect of the volume being drained is different. For example, if
the drain channels of FIG. 12 were extended into the very center of
the optic zone, fluent lens reactive media would be drained from
the very apex of the lens as opposed to the effect of the drain
channels shown, that are not extending into the optic zone and thus
will not drain from the optic zone to the same extent. If for
example there is a lake feature in the optic zone, and no drain
channels extend into the optic zone, then the lake feature cannot
be drained. Thus, changing the depth, width, size and extent and
location of drain channels affects the shape to which the fluent
lens reactive media will settle in a given period of time.
[0174] In different free-form processes, processing of a lens
precursor can include stabilization and fixing of the fluid lens
reactive mixture portion on the lens precursor to form a lens. A
controlled amount of fluent lens reactive media may be left on a
surface of a lens precursor form during separation of a substrate
and a lens precursor form from a reservoir containing excess
reactive mixture. In addition to the lens precursor features, which
may help control the amount of fluent lens reactive media that
sticks to the gelled portion, the combination of the reactive
mixture, speed of removal, and/or control of environmental factors
(e.g., temperature, oxygen level, etc.) can be changed to control
the amount of fluent reactive mixture that is present in the formed
lens precursor. Also, a portion of the reactive mixture may be
wicked, or to the contrary, additional fluent reactive mixture may
be added to the lens precursor using one of many methods known by a
person skilled in the art. Each of these possibilities may create
different base conditions that effect the interaction of different
lens precursor features, their design aspects respectively and the
nature of the fluid dynamics of the fluent reactive media upon the
underlying substructure of lens precursor features.
[0175] In some free-form methodology, once the amount of fluent
reactive mixture is on or proximate to the lens precursor and,
where appropriate, after a stabilization step, a fixing process may
be initiated to obtain the desired lens in an unhydrated state. In
accordance with the foregoing lens precursor features explanations,
some of the surfaces may not become a contiguous lens until fluent
lens reactive media is fixed accordingly. For example, where there
is a moat in a portion of the lens precursor form with a zero
thickness. In the case of a zero thickness moat, the gelled
features may end at the near periphery of the moat feature. Under
some conditions, fluent media can remain in the moat portion when
the lens precursor is removed from contact with the reservoir of
reactive media. Additional fluent media from regions surrounding
the moat region may then also flow into the moat region.
Nevertheless, until this fluent media is fixed there may not be
gelled material in this region, but after fixation the moat region
may be subsequently included as a portion of the gelled lens
product after subsequent processing.
Methods of Forming a Lens Precursor with Lens Precursor
Features
[0176] Referring now to FIG. 3 (item 300), exemplary method steps
that may be used to implement certain exemplary embodiments of the
present invention are illustrated. In the previous discussion,
there have been descriptions of numerous types of lens precursor
features that may be included in a lens design. The exemplary
method steps provide means of designing lenses which may
incorporate all or some of these various features.
[0177] At 301, patient data may be collected. Collection of data
may occur at different times and using one or more of the many
known techniques in the art. For example, physical data can be
collected through a topographical exam which may yield guidance on
product base curve, diameter and thickness options, an
over-refraction exam which may yield low order optical
aberration(s) such as sphere power, cylinder power, and cylinder
axis, and/or a wavefront exam which may yield medium and higher
order optical aberration requirements including one or more of
spherical aberration, trefoil, coma, and pentafoil. Additional data
may include data, such as, patient's information obtained through
questionnaires and/or data obtained from an image received.
[0178] At 302, one or more subsets of patient data may be selected
to identify optical aberrations. Identified optical aberrations may
be used for the selection of a suitable standard product design or
a custom product design. Generally, standard products are offered
in discrete steps and may require some user accommodation to the
difference between the more exact needs and the closest available
standard product. When a custom product design is made a custom
product may include one or more parameters that may be available in
selectable values that may be between standard product incremental
steps or otherwise different from standard product definitions.
[0179] Accordingly, Custom product parameters may allow for more
precise sphere power, cylinder power, and cylinder axis (e.g.,
-3.125D/-0.47D.times.18.degree.) than standard products and may
include base curves, diameters, stabilization profiles, and
thickness profiles based upon a particular product offered and its
intended use. For example, the results of a collection of a
particular patient's data in step 301, analysis of the data in step
302 may result in determining that a desired product may provide
for astigmatic correction and in some cases for a prescription
where the correction is desired for a custom product with
specification of parameter requirements for more precise sphere
power, cylinder power, and axis.
[0180] At 303, mechanical parameters including one or more of
desired base curve, diameter, and center thickness can be selected.
If it is determined that a free-formed lens may be appropriate, at
304 one or more lens precursor features and defining parameters may
be selected based upon one or both of optical selections 302 and
mechanical parameter inputs 303.
[0181] Continuing with the example discussed with reference to step
302, it may be determined that the lens design may require lens
precursor features including stabilization zones to keep the
astigmatic correction oriented appropriately. Furthermore, it may
be desired that the lens have a single lens edge around the entire
periphery of the lens. Due to the nature of the optic zone
astigmatic correction, in an exemplary sense, it may be determined
that multiple volumator features may be required to reach a
desirable optic zone design and/or fabrication.
[0182] To identify the lenses, it may be determined that markings
of various kinds would be placed onto the feature design. Finally,
again in an exemplary sense, it may be determined that drain
channel features would also improve the design and/or manufacturing
aspects of the optic zones.
[0183] At 305, target lens thickness maps and their associated
files (which may contain a numerical representation of the
thickness map in a datafile format) may be generated or identified
from a database. At 305 the resulting definitions of the optic zone
needs of step 302, the mechanical definitions of 303, and the
complement of the lens precursor features of step 304 may be
consolidated into a model. The model would determine the
theoretical thickness by design that would appropriately perform
the desired function of the various regions. From the model,
thickness maps and associated files may be generated. As may be
clear from earlier sections, the generated designs and files may
result from one, or a plurality of desired lens precursor features
and the desired fluent lens reactive media surfaces for a target
design.
[0184] To provide some illustration of the type of results that may
come from step 305, a cross-sectional representation of a target
lens thickness map may be found in FIG. 4. The depiction shows the
lens design in curved space. At 410, a representation of the back
curve profile may be found. At 420, the Front Curve profile may be
found. When an associated file to this thickness map is referenced,
it may be a datafile that contains location variables in various
coordinate systems such as Cartesian coordinates, Polar
Coordinates, Spherical Coordinates or other known mathematical
coordinate formalisms. In the associated file for each of the
coordinate representations may also include thickness values of
some kind.
[0185] Referring now to FIG. 5, an example of an associated
datafile where the coordinates are indicated in Cartesian
coordinates is given. Target files and/or lens designs may be
created by combining select optical and mechanical requirements,
together with other features (e.g., a type of stabilization
mechanism such as a stabilization zone).
[0186] Referring now to FIGS. 6 and 6A, an example of utilizing
multiple software programs to create and output desired optical and
mechanical features to generate a target lens design is
illustrated. At 610, a model of a customized optic design is
presented where the representation may relate to the target
thickness of the design. The design can result from output from the
collection of refractions data as shown in item 615.
[0187] At 620, Stabilization Zones, and in item 630, a Smart
volumator Floor design may be constructed as output from an excel
based spreadsheet design as shown by item 625, for example the
spreadsheet including sets of data points as Cartesian coordinates.
These three model elements may be combined to result in a custom
lens design depicted in item 640. There can be a large number of
methods to formulate lens designs from various elements and methods
of modeling those elements and should not be limited by the
particular example given.
[0188] As an alternative, the calculation that is performed at step
305 may result in a waveform target rather than a thickness target.
Such a target design may be useful in some cases since the
metrology may directly result in a waveform output. Similar utility
of the target lens thickness maps that may be generated in step 305
may occur for target lens waveforms.
[0189] At 306, a model is formulated to generate lens precursor
forms that may appropriately result in a lens precursor that
matches the thickness targets or the waveform targets formed in
step 305. There may be numerous means to generate lens precursor
form design thickness maps. In some instances a kinetic fluent
media model may be applied which may model the manners that fluent
media may flow over solid gelled substrate material.
[0190] Alternately, an entirely empirical algorithm may result in
estimations for the lens precursor form thickness pattern that may
be required to result in a target lens design after the fluent
media reaches a stable state based on prior results of lens making
processing. It is apparent to one skilled in the art that numerous
modeling techniques that may include combinations of dynamic
modeling algorithms, and also, empirical models may be used to
convert a target lens thickness map into the model. As a result,
target lens designs, thickness maps and associated files for a
desired product may be generated from lens precursor designs,
thickness maps and files.
[0191] In a general sense, a target file, or portions thereof, may
be created at least in part by utilizing one or more of traditional
2-dimensional design methods, 3-dimensional design methods,
empirical methods, and by combinations of both traditional and
empirical methods. Examples of traditional methods may include one
or more of ray tracing, mathematical formulae, CAD/CAM/CAE, 2D
modeling software, 3D modeling software, computer programming
languages, Microsoft Excel, static modeling, fluid modeling, and
computational fluid dynamics software.
[0192] At 308, DMD shows including a DMD sub-sequences, which may
refer to the first generated DMD show from a series of shows
created by iteration, may be generated. Referring back to FIG. 6,
an exemplary representation of the modeled cumulative intensity
dosing desired to be performed is represented as item 650; which
may have been calculated based on the custom lens design, 640
discussed in earlier sections.
[0193] Based on models that correlate intensity and time of actinic
light exposure to a reactive monomer mixture to be utilized, values
of intensity and time may be calculated on a voxel by voxel basis.
These values may be used to create a DMD show that may execute
control of a light system with a DMD to expose an appropriate
Substrate to the calculated actinic radiation exposure on a voxel
by voxel basis. Additionally, there may be numerous methods for
converting the needed time and intensity values into a DMD show or
DMD subsequences.
[0194] In a non-limiting sense, the DMD show(s) may use grey scale
modulation to deliver variable exposures to voxels that relate to
the calculated exposure. Alternate methods may include exposing
voxels for maximal intensity exposures for a particular duty cycle
or percentage of time of the entire DMD show. If each voxel has a
calculated percentage of time, then the DMD show may be similar to
a movie where a number of frames is determined for the entire DMD
show (which may be called a "movie") and then the percentage would
relate to the ratio of the number of frames at a particular voxel
location that have high intensity to the total number of
frames.
[0195] When the DMD show is used to control the actinic radiation
exposure system, which may include a DMD as the light modulation
element, a lens precursor may be formed upon a substrate in step
number 309. After this processing has occurred, the lens precursor
may exist as a gelled formed material, the lens precursor form and
also have upon that gelled media a layer of fluent media which has
achieved a minimum energy state. Afterwards, this lens precursor
may then be subjected to actinic radiation to fix the lens
precursor into a completely gelled form resulting in some cases in
an ophthalmic lens. Either such a lens precursor or lens may be the
result of the process step indicated as number 309.
[0196] At step 310, a fabricated lens precursor or a finished
ophthalmic lens may be measured for its thickness by various
methods. These thickness results may then be compared to the
thickness maps and their associated files which were formulated in
Step 305 to determine conformance to a desired product design. As
previously mentioned, the "Thickness Map" may be a
wavefront-targeted map. In these cases, the measurement of 310 may
obtain the wavefront data itself. Implementing other manners of
measuring the thickness or wavefront information of the lens or
lens precursor are within the scope of the present invention.
[0197] In some cases, the result of the measurement at step 310 may
result in a lens precursor or lens that is close enough to its
target lens design to be acceptable. Under such circumstances, the
method shown in FIG. 3 may be complete. The result of the
measurement at step 310 may, on the other hand be unacceptable. If
the result is too far off from the desired target, in some cases,
it may be desirable to return to step 303 and possibly make
fundamental changes to the lens precursor design. Therefore, at
311, if required, a combination of optical parameters, mechanical
parameters, lens precursor features, lens precursor feature
parameters, fluent lens reactive media surface parameters,
fabrication process conditions, thickness maps, associated files,
DMD shows etc., may be added, removed, or modified and utilized in
attempts to fabricate a lens precursor closer to a desired product
design/design target.
[0198] Alternately, the step described above at 311 may occur when
the measurement step at 310 is found to indicate an acceptable
result. In these cases, the DMD show may represent an acceptable
show for the generation of a lens precursor or lens with the
designed characteristics. Such a show and associated design may be
a desirable starting point for an altered design that is
significantly close in design characteristics to the acceptable
result. Again, in such cases, at 311 and 312, a combination of
optical parameters, mechanical parameters, lens precursor features,
lens precursor feature parameters, fluent lens reactive media
surface parameters, Fabrication Process conditions, thickness maps,
associated files, DMD shows, etc., may be added, removed, or
modified and utilized in processing.
[0199] All of these methods may allow for additional feature
changes, particularly for the Optic Zone, to be added into the
method flow in a parallel manner. Proceeding to FIG. 3A (item 320),
an additional step 327 may be found. In an example of the more
general technique of adding in details in design into the method, a
step may be included where the medium and higher order aberration
corrections may be added into the target lens design at step 305 or
into the lens precursor form design at step 306. It is also
apparent that these separate add in elements may be used in a
stand-alone fashion, where the added element 327 defines the nature
of the region of the target design or the lens precursor design
entirely where it has relevance.
[0200] Alternately, the added in files may be combined with the
existing definitions in target lens design and lens precursor form
design that have resulted in the standard method flow. The added
files located at step 327 may relate to thickness maps associated
with the added content or alternately as has been discussed may
relate to added waveform aspects or maps for the particular
region.
[0201] An alternate process that can share the similarity of the
step 327 may be found by referring to FIG. 3B (item 340). In the
same or a very similar manner that additional feature design
aspects may be added into the method flow as thickness or wavefront
targeted additions, the DMD show details may be modified by DMD
sub-sequences. As shown in step 343, a non-limiting example of a
DMD file may result if medium and higher order aberration
corrections for a lens prescription are added into the existing DMD
show directly. In some cases, a mathematical operation may be used
to combine an added DMD sub-sequence. For example, an arithmetic
addition operation may be performed to alter an existing DMD show
or movie so for that certain defined voxel location, the sum of the
voxel values at the particular locations is calculated and used to
replace the value on a frame-by-frame basis. It may be possible for
many other types of operations to be performed including, for
example, subtractions, multiplications, divisions, Boolean
operations, etc.
[0202] In a similar sense, if the DMD Sub-sequence file in step 343
defines features that add additional feature thickness or waveform
equivalent thickness, then an additive process may result from
including the frames of the adder DMD file to run after the
existing DMD show has been performed. It may be apparent that the
existing frames may be added to the DMD show at any particular
location in the DMD show.
[0203] In the previous discussions relating to the methods of
forming ophthalmic lenses and lens precursors with the various
features that are possible and those that are mentioned, the
terminology and the discussions relate particularly to the
technologies relating to free-form manufacturing of ophthalmic
lenses and lens precursors utilizing actinic radiation and digital
mirror devices to control the details of the fabrication process.
The inventive concepts herein, relate to DMD based free-form art
but are also more generally applicable. For example, the step
number 308 labeled DMD start show may relate to generating a
control program for a stereolithography manufacturing tool.
[0204] A lens precursor may be formed using this type of
manufacturing tool by using the stereolithography tool to form the
lens precursor form. In a second step, for example, fluent reactive
media may be added onto the lens precursor form manufactured by
stereolithography. Once the fluent media is added, the combination
may now define an equivalent of a lens precursor. The nature of the
flow of the fluent media over the form may be similar to the flow
in a voxel by voxel free-formed lens precursor. Therefore,
additional methodology may derive by defining lens precursor
features by different types of methods to form the basic lens
precursor form which will then interact with the fluent media and
are within the scope of the present invention. From a more general
sense, any method including free-form voxel based lithography,
stereolithography, mechanical lathing, part molding to mention a
few examples, may comprise art within the scope of this
disclosure.
Automation of the Design and Fabrication of Lens Precursors with
Features
[0205] Referring to FIG. 7, a schematic diagram of an exemplary
processor that may be used for modeling software used in some parts
of the present invention is depicted. The controller 700 includes a
processor 710, which may include one or more processor components
coupled to a communication device 720. The communication device 720
may also be configured to communicate information via a
communication channel to electronically transmit and receive
digital data related to the functions discussed herein.
[0206] The communication device 720 may also be used to
communicate, for example, with one or more human readable display
devices, such as, for example: an LCD panel, a LED display or other
display device or printer.
[0207] The processor 710 may also be in communication with a
storage device 730. The storage device 730 may comprise any
appropriate information storage device, including combinations of
magnetic storage devices (e.g., magnetic tape, radio frequency
tags, and hard disk drives), optical storage devices, and/or
semiconductor memory devices such as Random Access Memory (RAM)
devices and Read-Only Memory (ROM) devices.
[0208] The storage device 730 may store the modeling program 740
for controlling the processor 710. The processor 710 performs
instructions of the program 740, and thereby operates in accordance
with the present invention. For example, the processor 710 may
receive information descriptive of a target lens design, lens
precursor, DMD files, patient information, lens optical
performance, eye care practitioner's office data, lens precursor
features, measured thickness profiles, and the like. The storage
device 730 may also store and send all or some of the said
information sent to the processor in one or more databases 750 and
760.
[0209] The modeling program 740 is operative with the processor 710
to cause the apparatus 700 to receive digital data descriptive of
one or more optical aberrations associated with a wearer of the
ophthalmic lens (FIG. 3, step 302), receive digital data
descriptive of at least one desired mechanical parameter of the
ophthalmic lens (FIG. 3, step 303), receive input from an operator
descriptive of at least one topological feature of the lens
precursor form substructure (FIG. 3, step 304) and generate a DMD
show for use in a stereolithographic ophthalmic lens precursor form
manufacturing tool (step 308). It may also cause the apparatus to
receive digital data comprising a design thickness map of at least
a portion of the lens precursor form or a lens precursor (FIG. 3,
step 305 or 306), receive digital data comprising measured
thicknesses of at least a portion of a lens precursor form or lens
precursor manufactured by the manufacturing tool and compare the
measured thicknesses with the design thickness map to determine
conformance to the desired design (FIG. 3, step 310) and, if
necessary, generate an alternate instruction set for use in the
ophthalmic lens precursor form manufacturing tool (FIG. 3, step
311).
[0210] In the same fashion, the modeling program 740 may be
operative with the processor 710 to cause the apparatus 700 to
perform step 312 of FIG. 3, steps 302-308, 310-312 and 327 of FIG.
3A and steps 302-308, 310-312 and 343 of FIG. 3B.
Empirical Methods of Determining Target Files
[0211] Empirical determination of a target file or portions
thereof, may involve using a free-form method to fabricate one or
more of a lens, a lens precursor, a lens precursor form, and lens
precursor features from which measured thickness profiles, or
portions thereof, may be substituted and used in subsequent target
files. For example, due to the complex nature of the fluent media
and gelled form interaction, it may sometimes only be possible to
fabricate desired optic zones with reduced height stabilization
zone features, as compared to system designed stabilization zone
features. Therefore, system calculated stabilization zone features
may subsequently be replaced by corresponding measured thickness
resulting profiles for the reduced height stabilization zone
features that were empirically demonstrated to result in improved
fabrication results.
Manners of Representing Designs in Cross Sectional Displays
[0212] Referring now to FIG. 8A, a cross-sectional representation
of a non-round exemplary lens precursor 800A in 2-dimensional
curved space is depicted. The exemplary lens may be classified as a
single part design. By representing a top down view (item 801A)
with a variety of cross sectional representations, some of the
complexity of the actual topological and thickness variations may
be displayed. Cross-section 805A illustrates an example of a
significantly symmetrical (i.e. about symmetrical) thickness
profile since with reference to a focal point of the lens, which
may be in some examples the center of the optic zone, there can be
a similar length of lens material from the focal point to a "right"
side edge as to a "left" side edge in the cross section
representation. Cross-sections 810A and 815A illustrate examples of
non-symmetrical thickness profiles, since there are different
lengths and thicknesses around the focal point for these directions
of cross section.
[0213] A different manner of representing lenses by cross section
may be understood by referring to FIG. 8B, a cross-sectional
representation of a non-round exemplary lens precursor 800B in
2-dimensional flat space. (The top down representation is depicted
as item 801B.) In this exemplary representation, where the
illustrated thickness profiles are exaggerated, the flat space
representation transforms the back curve shape into a flat shape.
In this type of representation, Cross-section 820B illustrates an
example of a significantly symmetrical thickness profile.
Cross-sections 825B and 830B illustrate examples of non-symmetrical
thickness profiles.
Single and Multipart Designs--Background
[0214] Target files may be represented by one or more of continuous
surface features, non-continuous surface features, and discrete
features that when combined, may produce one or more of complete
continuous surfaces, non-continuous surfaces, and discrete zones.
For example, target files represented by one or both of single,
smooth, continuous and single, non-continuous surfaces may be
commonly referred to as single part designs as the shape in FIG. 3A
and FIG. 3B may represent. Additionally, for example, target files
may be represented by multiple discrete features. These types of
design representations may be commonly referred to as multi-part
designs.
Method of Using Multi Part Lens Profiles to Generate a Lens
Precursor with Features
[0215] As just mentioned, a target lens design can have discrete
characteristics that make them candidates to be called multi-part
designs. The discrete characteristics may result in a random manner
as a result of a designing process, however, more typically they
are formed because the design may be formed by the direct
combination of different design "pieces" that relate to just a
region of a full lens design. These pieces may also be considered
as independent "parts" which when combined together may create a
multi-part design.
[0216] Such a multi-part design concept may allow for a
non-complete surface of a desired product or target file to be
utilized in lens precursor fabrication. As a result, in practice a
complete surface may not ever be created, stored as a single or
multiple files, or transmitted to a fabrication facility.
[0217] For example, discrete, non-smooth, non-continuous data
relating only to a desired product optic zone, base curve and
diameter may need to be transmitted from an eye care practitioner's
office to a fabrication facility in order for a desired product to
be fabricated using a contour forming process technology. The
transmitted data, which in its own right may represent or specify
only a piece of a lens design, may be combined with other pieces
for the remainder of a full design at a later time. For example,
after receiving a transmission of the product optic zone design
with a base curve and an overall lens design diameter, one may
combine these components with a lens edge and desired stabilization
zone features.
[0218] Moreover, at a different location, such as the production
facilities, these additional features may be recalled from catalog
items and together with fluent lens reactive media designs may
complete a smooth and continuous fabricated lens precursor. Other
lens fabrication techniques may require entire, complete surfaces
of a desired product to be known. For example, with direct lathing
of lenses, diamond tools have to follow pre-generated complete tool
paths to cut an entire surface of a desired product.
[0219] Referring now to FIG. 9A, a representation is illustrated of
a non-round single part design of an exemplary lens precursor 900A
and cross-sectional representations in both curved and flat space.
In this representation, the entire convex surface may be smooth and
continuous in nature. Convex profiles of cross-sections at 905A,
910A, 915A, 920A, 925A, and 930A are also shown as smooth,
continuous sections.
[0220] The designation of a design as a "Single Part Design" may be
dominated by the fact that the method to generate the lens design
generates the design aspects from a complete initial set of feature
specifications. Therefore, the shape alone of the resulting lens
may seem to have discrete parts but as they were combined together
in the initial specification such a lens may still be classified as
a single part design.
[0221] Referring now to FIG. 9B, representations of a non-round
single part design of an exemplary lens precursor 900B and
cross-sectional representations in both curved and flat space are
illustrated. It may be observed that these depictions show a design
in cross section, where the surface is neither smooth nor
continuous in nature. Nevertheless as was indicated this may be
considered a single part design and at the initial design step a
feature may have been chosen which results in the non-continuous
nature of the design. For example the gap in the cross section may
be caused by a moat feature 990B as illustrated. Also shown are
cross-sections of a surface at 935B, 940B, 945B, 950B, 955B, and
960B which may clearly show the lack of smoothness and continuity
in this SinglepPart design.
[0222] Referring now to FIG. 9C, representations of a multi-part
design concept of a smooth, continuous exemplary lens precursor
900C, is given. Included in the Figure are cross-sectional
representations of discrete features that may make up a lens
precursor design. For example, the three different features
represented by 965C, 970C and 975C. A smooth and continuous convex
cross-section 980C produced from this combination of discrete
features may also be observed. Also shown is a plan view
representation, item 901C, that depicts a smooth and continuous
round multi-part design lens precursor 900C, all in 2-dimensional
curved space. The exemplary different "Parts" that are included in
this multi-part design may be an annular Lens edge 965C, a
stabilization zone feature 970C, and an optic zone 975C are shown.
A combination of discrete features producing a smooth and
continuous convex cross-section 980C, and a plan view of a lens
precursor design 900C are also shown.
[0223] Referring now to FIG. 9D, representations of a multi-part
design concept of a non-smooth, non-continuous exemplary lens
precursor 900D are depicted. Also included in FIG. 9D are
cross-sectional representations of discrete features that may make
up a lens precursor design. As may be observed the multi-part
design may include a non-smooth, non-continuous convex
cross-section 985D produced from a combination of discrete
features. The plan view may also show a top down representation of
this non-smooth, non-continuous round multi-part design Lens
precursor 900D. Likewise, these representations may be made in
2-dimensional curved space illustrations. Further, an annular lens
edge 965D feature, an optic zone 975D feature, and a combination of
discrete features may be a non-continuous, non-smooth cross-section
985D as illustrated. Discontinuities can exist between the lens
edge 965D and optic zone 975D.
The Digital Core-Break Concept
[0224] Referring again to FIGS. 1A, 1B, 1C, 1D, and 1E, numerous
types of lens precursor features may have been combined to form the
different designs. The associated target files may be constructed
by combining a number of such different features together. Each of
these combined features may be picked from one or both of catalog
Items and non-catalog Items. A non-catalog Item in this case may
indicate something that has been newly modeled or created for a
specific lens design.
[0225] When a lens design may be formed by the combination of
various lens precursor features a new lens precursor target design
may be defined. However, it may be apparent that a great number of
different lenses that are similar to the lens precursor target
design may also be formed by assembling the same combination of
precursor elements but whose parametric values may be
different.
[0226] For example, the height of a particular stabilization design
and/or lens design, the depth of a particular volumator feature may
be varied creating similar but different designs. For some families
of related designs, it may be desirable to keep select lens
precursor features and/or select feature control parameters
constant within a range of lens designs. When a subset of the
feature control parameters for a collection of select lens
precursor features are kept constant, while parameters on the other
features may vary, the resulting family of designs may be referred
to as a digital core break. Furthermore, one or more digital core
break(s) may be present within a range of lens designs. It will be
apparent from the teachings of the present disclosure to one
skilled in the art that portions of the DMD files or DMD shows
associated with different lens production in a digital core break,
may be similar or identical to each other.
[0227] To further understand this concept of digital core break,
consider a theoretical Acuvue Toric Precise Limited.TM., a system
generated custom product. There are a large number of lenses in
this product family with a variety of different values for their
low order sphere power, cylinder power and cylinder axis correction
that may be offered.
[0228] The variation however may only cover a sphere power range of
-3.00D to 0.00D and a cylinder power range of -2.00D to 0.00D.
Continuing this example, these products within these various ranges
may have identical lens edge, stabilization zone features and
volumator features regardless of the sphere power, cylinder power
and cylinder axis offered. Acuvue Toric Precise Limited.TM.
therefore, may be characterized as only having one Digital Core
Break.
[0229] A further example, may be that of Acuvue Toric Precise
Plus.TM., a theoretical custom product whereby infinite parameters
of only low order sphere power, cylinder power and cylinder axis
correction may be offered in a large sphere power range of -20.00D
to +20.00D and cylinder power range of -10.00D to 0.00D. Acuvue
Toric Precise Plus.TM. may have three digital core breaks since
within each sphere power range, for example, of -20.00D to -10.00D,
-9.99D to +9.99D and +10.00D to +20.00D, lens edge, stabilization
zone features and volumator features may be identical, but
different in each of the three Digital Core Breaks.
[0230] An advanced target file may be created by starting with a
base target file and modifying it to add characteristics. For
example, a lens design to provide trefoil and coma correction
together with corrections for a sphere power of -5.67D and a
cylinder power of -4.56D at a cylinder axis of 78.degree., may be
created by recalling catalog items for an Acuvue Toric Precise
Plus.TM.-5.67D/-4.56D.times.78.degree. design, and incorporating
desired high order correction components into these select recalled
catalog items.
[0231] In general, there may be numerous manners and techniques
within the scope of this inventive art to generate DMD files or DMD
shows. The traditional methods, as depicted in FIG. 3, may be
used.
[0232] Additionally, DMD files or DMD shows may also be generated
by recalling catalog Items which then may be modified as needed.
Previous DMD files or DMD shows may also be modified by numerous
manners including adding in DMD files for new or modified features.
Similar to target files, DMD files and/or DMD shows may be created
from base, target files, DMD filed and/or DMD shows and
incorporating instructions into them that may yield medium or high
order correction into the fabricated lens. Examples of sample
portions of DMD files are shown in both FIGS. 5 and 10.
[0233] In some further aspects, a lens precursor or lens precursor
form may be fabricated via utilization of one or both of DMD files
and DMD shows. For example, pertinent data to fabricate a desired
lens precursor 105B or lens precursor form 100A may be contained in
a single DMD file or DMD show, such as, instructions to generate
lens edges, stabilization zone features, and optic zones.
Additionally, for example, pertinent data to fabricate a desired
lens precursor or lens precursor form may be contained in multiple
DMD files or DMD shows such as, one DMD file or DMD shows may
include instructions to generate lens edges and stabilization zone
features, while a different DMD file or DMD show may contain
instructions to generate optic zones and drain channel features.
Further, pertinent data to fabricate desired lens precursors
features within a desired lens precursor or lens precursor form can
be distributed, for example, across one or both of DMD files and
DMD shows. An example of a sample DMD show, rotated by 180.degree.
around the y-axis and rotated counter-clockwise by 45.degree. in
the x-y plane is illustrated in FIG. 11.
[0234] An entire DMD file or DMD show, or portions thereof, may be
utilized to overwrite a preceding DMD file or DMD show, or portions
thereof. For example, a DMD file including of circumferential drain
channel features may be superimposed on a preceding DMD file to
allow drain channel features to be fabricated in a lens precursor
without changing the preceding DMD file. An example of a sample DMD
show plus a DMD file including circumferential drain channels is
illustrated in FIG. 12. Another example may be to utilize a DMD
file by superimposing it on a preceding DMD show to change one or
both edge shape and profile of a lens precursor being fabricated,
as illustrated in FIG. 13A and FIG. 13B.
[0235] FIG. 13A illustrates an example of a sample DMD show with a
DMD file containing circumferential drain channel instructions with
a DMD file containing a changed edge curvature instruction section
rotated by 180.degree. around the y-axis and rotated
counter-clockwise by 45.degree. in an x-y plane as compared to the
lens fabricated from the DMD show, a photograph of which is
illustrated in FIG. 13B.
[0236] Complete or incomplete design target files, DMD files, DMD
shows, DMD Iteration shows, catalog items, non-catalog items, etc.,
may be combined with other complete or incomplete design target
files, DMD files, DMD shows, DMD Iteration shows, catalog Items,
non-catalog Items, etc., and maybe incorporated into DMD files and
DMD shows from which a desired lens precursor may be fabricated.
For example, if only a thickness description of an optic zone is
passed to a fabrication facility, it may be converted into a DMD
file and may be combined with another DMD file that may contain a
lens edge and stabilization zone features. Therefore, a lens
precursor may be fabricated without ever having specified a
complete lens design or lens precursor design profile. For example,
if neither individual, nor combined DMD files describe a complete
surface profile, fluent lens reactive media may still connect an
optic zone to stabilization zone features, thereby, completing a
surface profile.
[0237] A lens precursor or lens precursor form may be measured for
conformance to a design target file pre-, post-, or pre- and
post-fixing processes. Resulting measurements may be utilized in an
iterative loop and may enable a desired lens precursor 105 to be
fabricated. An example of a representation of two cross-sections
(at 45.degree. and 135.degree.) of a lens design, DMD shows, and
measured lens precursor in flat space are illustrated in FIG.
14.
[0238] In some cases, a fabricated lens precursor may not precisely
match a target file, or fall within specified acceptance criteria.
For example, a fabricated lens precursor may include regions that
may be one or more of the following: thicker than desired, thinner
than desired, and at a desired target thickness. Several options
may exist to fabricate a subsequent lens precursor that may be
closer to a target file than its predecessor. For example, options
may include utilizing one or more of a same DMD show with identical
fabrication process conditions from a prior attempt, a modified DMD
show with identical fabrication process conditions from a prior
attempt, a same DMD show and modified fabrication process
conditions, and a modified DMD show and modified fabrication
process conditions.
[0239] One or both of a DMD file and a DMD show may be modified in
many different ways, and may be based upon one or both of
experience and differences between measured lens precursors and
desired thickness maps. For example, a DMD file may be modified by
one or more of changing select lens precursor feature design values
and parameters within a file such as for optic zone, adding values
and parameters for fabricating additional lens precursor features
such as a moat feature, removing values and parameters of select
fabricated lens precursor features such as drain channel features,
and spatially redistributing values and parameters of select
fabricated lens precursor features such as a volumator feature.
[0240] Specific examples have been described to illustrate the
creation of lens precursor features, and the methods to create
lenses and lens precursors with a variety of different features,
and the nature and methods of forming DMD shows and DMD files to
form lenses and lens precursors. These examples are for
illustration and are not intended to limit the scope of the
invention in any manner. Accordingly, the description and claims
are intended to embrace all variations and alternatives that may be
apparent to those skilled in the art.
* * * * *