U.S. patent application number 13/690829 was filed with the patent office on 2013-05-30 for optical coating method, apparatus and product.
The applicant listed for this patent is Christopher Morton Lee, Xiao-feng Lu, Michael Xu Ouyang, Junhong Zhang. Invention is credited to Christopher Morton Lee, Xiao-feng Lu, Michael Xu Ouyang, Junhong Zhang.
Application Number | 20130135741 13/690829 |
Document ID | / |
Family ID | 47324477 |
Filed Date | 2013-05-30 |
United States Patent
Application |
20130135741 |
Kind Code |
A1 |
Lee; Christopher Morton ; et
al. |
May 30, 2013 |
OPTICAL COATING METHOD, APPARATUS AND PRODUCT
Abstract
This disclosure is directed to an improved process for making
glass articles having optical coating and easy-to clean coating
thereon, an apparatus for the process and a product made using the
process. In particular, the disclosure is directed to a process in
which the application of the optical coating and the easy-to-clean
coating can be sequentially applied using a single apparatus. Using
the combination of the coating apparatus and the substrate carrier
described herein results in a glass article having both optical and
easy-to-clean coating that have improved scratch resistance
durability and optical performance, and in addition the resulting
articles are "shadow free."
Inventors: |
Lee; Christopher Morton;
(Corning, NY) ; Lu; Xiao-feng; (Jiangmen City,
CN) ; Ouyang; Michael Xu; (Painted Post, NY) ;
Zhang; Junhong; (Fuzhou, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lee; Christopher Morton
Lu; Xiao-feng
Ouyang; Michael Xu
Zhang; Junhong |
Corning
Jiangmen City
Painted Post
Fuzhou |
NY
NY |
US
CN
US
CN |
|
|
Family ID: |
47324477 |
Appl. No.: |
13/690829 |
Filed: |
November 30, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61565024 |
Nov 30, 2011 |
|
|
|
61709423 |
Oct 4, 2012 |
|
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Current U.S.
Class: |
359/580 ;
118/500; 427/162; 427/596 |
Current CPC
Class: |
G02B 1/11 20130101; C03C
2217/78 20130101; C03C 2218/151 20130101; B05D 5/061 20130101; C03C
2218/32 20130101; C23C 14/24 20130101; C23C 14/12 20130101; B05C
13/00 20130101; C03C 17/42 20130101; C03C 2217/73 20130101; C03C
2217/76 20130101; C03C 17/002 20130101; C23C 14/505 20130101; G02B
1/115 20130101; C23C 14/044 20130101; C03C 2217/734 20130101; C23C
14/56 20130101 |
Class at
Publication: |
359/580 ;
427/162; 427/596; 118/500 |
International
Class: |
G02B 1/11 20060101
G02B001/11; B05D 5/06 20060101 B05D005/06 |
Claims
1. A method for making a glass article having an optical coating
and an easy-to-clean (ETC) coating on top of the optical coating,
the method comprising: providing a coating apparatus having a
vacuum chamber for deposition of an optical coating and an ETC
coating; providing a magnetic rotatable dome within said vacuum
chamber for magnetically positioning a magnetic substrate carrier
for receiving a glass substrate thereon that is to be coated;
providing within said vacuum chamber source materials for the
optical coating and source materials for the ETC coating; loading
the glass substrate on the magnetic substrate carrier and
magnetically attaching the magnetic substrate carrier having the
glass substrate thereon to the magnetic rotatable dome; evacuating
the vacuum chamber; rotating the magnetic rotatable dome and
depositing an optical coating on the glass substrate; rotating the
magnetic rotatable dome and depositing the ETC coating on top of
the optical coating following deposition of the optical coating,
wherein the optical coating is not exposed to ambient atmosphere
prior to the deposition of the ETC coating; and removing the glass
substrate having the optical coating and the ETC coating from the
vacuum chamber to obtain a glass substrate having a shadow-free
optical coating deposited on the glass substrate and the ETC
coating deposited on the optical coating.
2. The method according to claim 1, further comprising curing the
ETC coating.
3. The method according to claim 2, wherein the ETC coating is
cured in air at room temperature.
4. The method according to claim 2, wherein the ETC coating is
cured by heating the ETC coating.
5. The method according to claim 1, wherein the vacuum chamber is
evacuated to a pressure of less than or equal to 10.sup.-4
Torr.
6. The method according to claim 1 further comprising densifying
the optical coating as the optical coating is deposited.
7. The method according to claim 1, wherein the vacuum chamber
contains at least one e-beam source for vaporizing the source
materials for the optical coating.
8. The method according to claim 7, wherein the at least one e-beam
source comprises greater than or equal to 2 and less than or equal
to 6 e-beam sources and an e-beam from each source is directed to a
separate container holding a material being coated.
9. The method according to claim 1, wherein the magnetic substrate
carrier is selected from the group consisting of a fixed magnetic
substrate carrier and an adjustable magnetic substrate carrier.
10. The method according to claim 1, wherein depositing the optical
coating comprises depositing a multilayer optical coating
comprising at least one period of a high refractive index material
and a low refractive index material, wherein: the high refractive
index material is selected from the group consisting of ZrO.sub.2,
HfO.sub.2, Ta.sub.2O.sub.5, Nb.sub.2O.sub.5, TiO.sub.2,
Y.sub.2O.sub.3, Si.sub.3N.sub.4, SrTiO.sub.3, WO.sub.3; and the low
refractive index material is selected from the group consisting of
SiO.sub.2, MgF.sub.2, YF.sub.3, YbF.sub.3 and Al.sub.2O.sub.3.
11. The method according to claim 1, wherein the glass substrate is
formed from ion-exchanged silica glass, non-ion-exchanged silica
glass, aluminosilicate glass, borosilicate glass,
aluminoborosilicate glass, or soda lime glass.
12. The method according to claim 1, wherein the source material
for the ETC coating is a alkyl perfluorocarbon silane of formula
(R.sub.F).sub.xSiX.sub.4-x, where R.sub.F is a linear
C.sub.6-C.sub.30 alkyl perfluorocarbon, X.dbd.Cl or --OCH.sub.3--
and x=2 or 3.
13. The method according to claim 1, wherein a variation in a
thickness of the optical coating across a coated surface of the
glass substrate is less than or equal to 3%.
14. The method according to claim 1, wherein a variation in a
thickness of the optical coating across a coated surface of the
glass substrate is less than or equal to 2%.
15. The method according to claim 1, wherein a variation in a
thickness of the optical coating across a coated surface of the
glass substrate is less than or equal to 1%.
16. A magnetic substrate carrier for holding a substrate during a
coating process, the magnetic substrate carrier comprising: a
non-magnetic substrate carrier base; a plurality of magnets
attached to the non-magnetic substrate carrier base; a plurality of
pins for supporting a surface of a glass substrate positioned on
the magnetic substrate carrier; a spring system comprising a
retractable pin held in place by a spring that retracts the
retractable pin, the retractable pin being extendable in a
direction opposite the spring, a plurality of fixed pins, and a
plurality of side stoppers extending from the non-magnetic
substrate carrier base for a distance such that, when the glass
substrate is positioned on the plurality of pins, tops of the
plurality of side stoppers are below a top surface of the glass
substrate.
17. A magnetic substrate carrier for holding substrates during a
coating process, the magnetic substrate carrier comprising: a
non-magnetic carrier base; a plurality of magnets attached to the
non-magnetic carrier base; a plurality of pins for supporting a
surface of a glass substrate; a housing with a retractable pin
disposed in the housing, wherein the retractable pin is held in
place by a spring, the retractable pin being outwardly biased from
the housing; optional stoppers; and a plurality of movable pins for
holding an edge of a glass substrate.
18. A glass article comprising an optical coating and an
easy-to-clean coating on top of the optical coating, the glass
article being shadow free across an optically coated surface of the
glass article, wherein: the optical coating comprises a plurality
of periods consisting of a layer of high refractive index material
H having an index of refraction n greater than or equal to 1.7 and
less than or equal to 3.0, and a layer of low refractive index
material L having an index of refraction n greater than or equal to
1.3 and less than or equal to 1.6, the layer of high refractive
index material H being a first layer of each period and the layer
of low refractive index material L being a second layer of each
period; and an SiO.sub.2 capping layer having a thickness in a
range greater than or equal to 20 nm and less than or equal to 200
nm applied on top of the plurality of periods.
19. The glass article according to claim 18, wherein a number of
coating periods is in a range from greater than or equal to 2 and
less than or equal to 1000.
20. The glass article according to claim 18, wherein the optical
coating has a thickness in a range from greater than or equal to
100 nm to less than or equal to 2000 nm.
21. The glass article according to claim 18, wherein a number of
coating periods is in a range from greater than or equal to 2 and
less than or equal to 20, and a thickness of each layer of high
refractive index material H and low refractive index material L is
in a range from greater than or equal to 5 nm and less than or
equal to 200 nm.
22. The glass article according to claim 18, wherein the layer of
high refractive index material H is selected from the group
consisting of ZrO.sub.2, HfO.sub.2, Ta.sub.2O.sub.5,
Nb.sub.2O.sub.5, TiO.sub.2, Y.sub.2O.sub.3, Si.sub.3N.sub.4,
SrTiO.sub.3 and WO.sub.3.
23. The glass article according to claim 18, wherein the layer of
low refractive index material L is selected from the group
consisting of SiO.sub.2, MgF.sub.2, YF.sub.3, YbF.sub.3, and
Al.sub.2O.sub.3.
24. The glass article according to claim 18, wherein the glass
article has a water contact angle of at least 75.degree. after
6,000 abrasion cycles.
25. The glass article according to claim 18, wherein after 8,000
abrasion cycles, scratches on a surface of the glass article are
less than 2 mm in length.
26. The glass article according to claim 18, wherein a %
Reflectance of the glass article after at least 8,000
abrasion/wiping cycles is substantially the same as the %
Reflectance of an unabraded/unwiped glass article.
27. The glass article according to claim 18, wherein a %
Transmission of the glass article after at least 8,000
abrasion/wiping cycles is substantially the same as the %
Transmission of an unabraded/unwiped glass article.
28. The glass article according to claim 18, wherein a variation in
a thickness of the optical coating across a coated surface of the
glass article is less than or equal to 3%.
29. The glass article according to claim 18, wherein a variation in
a thickness of the optical coating across a coated surface of the
article is less than or equal to 2%.
30. The glass article according to claim 18, wherein a variation in
a thickness of the optical coating across a coated surface of the
glass article is less than or equal to 1%.
31. A coating apparatus for coating a substrate with an optical
coating and an ETC coating, the coating apparatus comprising: a
vacuum chamber; a magnetic rotatable dome positioned in the vacuum
chamber; at least one e-beam source positioned in the vacuum
chamber; at least one thermal evaporation source positioned in the
vacuum chamber; and a shadow mask adjustably positioned on a
support within the vacuum chamber.
32. The coating apparatus of claim 31, further comprising a plasma
source positioned in the vacuum chamber.
33. The coating apparatus of claim 31, wherein the magnetic
rotatable dome comprises: an opening at a top center of the
magnetic rotatable dome; a transparent glass plate covering the
opening of the magnetic rotatable dome; and a quartz monitor
positioned in an opening in the transparent glass plate for
monitoring a deposition rate of coating material deposited in the
vacuum chamber.
34. The coating apparatus of claim 33, further comprising an
optical fiber positioned above the transparent glass plate, wherein
the optical fiber collects light reflected from the transparent
glass plate as the transparent glass plate is coated to determine a
change in reflectance of the transparent glass plate and thereby a
thickness of coatings applied to the transparent glass plate.
35. The coating apparatus of claim 31, wherein the magnetic
rotatable dome is attached to a vacuum shielded rotation shaft to
facilitate rotation of the magnetic rotatable dome.
36. The coating apparatus of claim 31, further comprising at least
one magnetic substrate carrier magnetically attached to the
magnetic rotatable dome.
Description
PRIORITY
[0001] This application claims the priority of U.S. Provisional
Application No. 61/565,024 titled "Process for Making of Glass
Articles With Optical and Easy-To-Clean Coatings" filed Nov. 30,
2011, the content of which is relied upon and incorporated herein
by reference in its entirety and U.S. Provisional Application No.
61/709,423 titled "Optical Coating Method, Apparatus and Product"
filed Oct. 4, 2012, the content of which is relied upon and
incorporated herein by reference in its entirety.
FIELD
[0002] This disclosure is directed to a process for making glass
articles having an optical coating and an easy-to-clean (ETC)
coating thereon, an apparatus for performing the process and an
article made using the process. In particular, the disclosure is
directed to a process in which the application of the optical
coating and the ETC coating can be sequentially carried out using
the same apparatus.
BACKGROUND
[0003] Glass, and in particular chemically strengthened glass, has
become the material of choice for the view screen of many, if not
most, consumer electronic products. For example, chemically
strengthened glass is particularly favored for "touch" screen
products whether they be small items such as cell phones, music
players, eBook readers and electronic notepads, or larger items
such as computers, automatic teller machines, airport self-check-in
machines and other similar electronic items. Many of these items
require the application of antireflective ("AR") coatings on the
glass in order to reduce the reflection of visible light from the
glass and thereby improve contrast and readability, for example,
when the device is used in direct sunlight. However, some of the
drawbacks of an AR coating are its sensitivity to surface
contamination and its poor anti-scratch durability, that is, the AR
coating becomes easily scratched during use, for example, by a
wiping cloth or the dirt and grime on a user's finger. Fingerprints
and stains are very noticeable on an AR coated surface and are not
always easily removed. As a result, it is highly desirable that the
glass surface of any touch device be easy to clean which is
achieved by applying an easy-to-clean (ETC) coating to the glass
surface.
[0004] The current processes for making glass articles having both
antireflection and ETC coatings requires that the coating be
applied using different equipment, and consequently separate
manufacturing runs. The basic procedure is to apply the
antireflection ("AR") coating to a glass article using, for
example, a chemical vapor ("CVD") or physical vapor deposition
("PVD") method. In conventional processes, an optically coated
article, for example, one with an AR coating, will be transferred
from the optical coating apparatus to another apparatus to apply
the ETC coating on top of the AR coating. While these processes can
produce articles that have both an AR and an ETC coating, they
require separate runs and have higher yield losses due to the extra
handling that is required. This may result in poor reliability of
the final product due to contamination arising from the extra
handling between the AR coating and ETC coating procedures. For
example, using the conventional 2-step coating process of ETC over
an optical coating results in an article that is easily scratched
in touch screen applications. In addition, while the AR coated
surface can be cleaned before applying the ETC coating, this
involves additional steps in the manufacturing process. All the
additional steps increase the product costs. Consequently,
alternative methods and apparatuses are needed by which both
coatings can be applied using the same basic procedure and
equipment, thus reducing manufacturing costs. Advantages of the
process disclosed herein and resulting products are set forth in
the following paragraphs and claims.
SUMMARY
[0005] In one embodiment, the disclosure provides a method for
making a glass article having an optical coating and an
easy-to-clean coating on top of the optical coating includes
providing a coating apparatus having a vacuum chamber for the
deposition of an optical coating and an ETC coating, providing a
magnetic rotatable dome within said chamber for magnetically
positioning a magnetic substrate carrier for receiving a glass
substrate thereon that is to be coated, and providing within said
vacuum chamber source materials for the optical coating and source
materials for the ETC coating. The method also includes loading the
glass substrate on the magnetic substrate carrier and magnetically
attaching the magnetic substrate carrier having the glass substrate
thereon to the dome, evacuating the vacuum chamber, rotating the
dome and depositing an optical coating on the glass substrate, and
rotating the dome and depositing the ETC coating on top of the
optical coating following deposition of the optical coating, where
the optical coating is not exposed to ambient atmosphere prior to
the deposition of the ETC coating. The method further includes
removing the substrate having the optical coating and the ETC
coating from the chamber to obtain a glass substrate having a
shadow-free optical coating deposited on the substrate and an ETC
coating deposited on the optical coating.
[0006] In another embodiment, the disclosure provides a magnetic
substrate carrier for holding a substrate during a coating process,
where the magnetic substrate carrier includes a non-magnetic
substrate carrier base having a plurality of magnets attached to
the non-magnetic carrier base, a plurality of pins for supporting a
surface of a glass substrate positioned on the substrate carrier,
and a spring system that includes a retractable pin held in place
by a spring that retracts the retractable pin, where the
retractable pin is extendable in a direction opposite the spring.
The spring system also includes a plurality of fixed pins and a
plurality of stoppers extending from the non-magnetic substrate
carrier base for a distance such that, when the glass substrate is
positioned on the plurality of pins, the tops of the stoppers are
below a top surface of the glass substrate.
[0007] In yet another embodiment, the disclosure provides a
magnetic carrier for holding substrates during a coating process,
where the substrate carrier includes a non-magnetic carrier base, a
plurality of magnets attached to the non-magnetic carrier base, and
a plurality of pins for supporting a surface of a glass substrate.
The substrate carrier also includes a housing for a retractable pin
and a retractable pin disposed in the housing, where the
retractable pin is held in place by a spring and the retractable
pin is outwardly biased from the housing, optional stoppers, and a
plurality of movable pins for holding an edge of the glass
article.
[0008] In yet another embodiment, the disclosure provides a glass
article having an optical coating and an easy-to-clean coating on
top of the optical coating, where the glass article is shadow free
across an optically coated surface of the glass article. The
optical coating includes a plurality of periods consisting of a
layer of high refractive index material H having an index of
refraction n greater than or equal to 1.7 and less than or equal to
3.0, and a layer of low refractive index material L having an index
of refraction n greater than or equal to 1.3 and less than or equal
to 1.6. The layer of high refractive index material is the first
layer of each period and the layer of low refractive index material
L is the second layer of each period. An SiO.sub.2 capping layer
having a thickness in the range greater than or equal to 20 nm and
less than or equal to 200 nm is applied on top of the plurality of
periods.
[0009] In another embodiment, the disclosure provides a coating
apparatus for coating a substrate with an optical coating and an
ETC coating. The coating apparatus may include: a vacuum chamber; a
magnetic rotatable dome positioned in the vacuum chamber; at least
one e-beam source positioned in the vacuum chamber; at least one
thermal evaporation source positioned in the vacuum chamber; and a
shadow mask adjustably positioned on a support within the vacuum
chamber.
[0010] Additional features and advantages of the methods described
herein will be set forth in the detailed description which follows,
and in part will be readily apparent to those skilled in the art
from that description or recognized by practicing the embodiments
described herein, including the detailed description which follows,
the claims, as well as the appended drawings.
[0011] It is to be understood that both the foregoing general
description and the following detailed description describe various
embodiments and are intended to provide an overview or framework
for understanding the nature and character of the claimed subject
matter. The accompanying drawings are included to provide a further
understanding of the various embodiments, and are incorporated into
and constitute a part of this specification. The drawings
illustrate the various embodiments described herein, and together
with the description serve to explain the principles and operations
of the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1A is a schematic drawing of a coating apparatus 100
according to one or more embodiments described herein;
[0013] FIG. 1B schematically depicts an enlarged view of glass
plate 116 and illustrates the opening 116a for receiving a quartz
monitor;
[0014] FIG. 1C schematically depicts an enlarged view of the glass
plate with the quartz monitor received within the opening and an
optical fiber, both of which are used to measure and control the
deposition of the optical coating materials onto glass substrates
attached to a substrate carrier;
[0015] FIG. 2 is a drawing representing a top-down view through a
section of the dome of the coating apparatus of FIG. 1A
illustrating a plurality of substrate carriers magnetically
attached to the dome;
[0016] FIG. 3A schematically depicts an oblique bottom-up side view
of a segment of the dome of the coating apparatus of FIG. 1A with a
plurality of substrate carriers magnetically attached to the
dome;
[0017] FIG. 3B schematically depicts a frame that supports the dome
segments 110a; frame 160 having an outer lip/rim 161 as is also
illustrated in FIG. 3A, an inner rim (not numbered) at opening 164
to which the rotation shaft 117 can be attached (not illustrated)
and a plurality of spokes 162 that are sufficiently wide to
accommodate the side edges of the dome segments as is illustrated
at 168;
[0018] FIG. 4A schematically depicts a non-magnetic substrate
carrier 130 having a plurality of elements 134 for magnetically
attaching the carrier to dome 110 and for holding a glass
substrate/article 140 during the coating process;
[0019] FIG. 4B is a side view of FIG. 4A illustrating a glass
substrate 140 resting on pins 136 that extend into the substrate
carrier base 130 for a distance from the substrate carrier surface
130a, a plurality of magnets 134 that extend from the surface 130a
of the substrate carrier 130 and through the substrate for a
distance beyond the base 130b, a side stopper 150 extending from
the base of carrier 130 to a distance from glass article 140's top
face 140a;
[0020] FIG. 5 schematically depicts one of the pins 138a and 138b
against which a glass substrate 140 is held by the force exerted
against it by a spring loaded adjustable pin 138a, and a shaped
edge 141 that is in contact with the pin, in this case a chamfered
edge;
[0021] FIG. 6 illustrates substrate carriers 130 attached to dome
110 such that the retractable pin 138A, is positioned perpendicular
to the rotation direction, that is, closer to opening at the top T
of the dome 110 than the pins 138b also illustrated in FIG. 6;
[0022] FIG. 7 a-c is a schematic representation of the fluorinated
silane grafting reaction with glass or an oxide AR coating;
[0023] FIG. 8 illustrates the AR optical coating layers that would
underlie the ETC coating to provide a barrier to isolate glass
surface chemistry and contamination, and further to provide a lower
activation energy site for fluorinated silanes to chemically bond
to the AR optical coating with maximum coating density as well as
crosslinking over the coated surface in order to maximize abrasion
reliability (durability);
[0024] FIG. 9 is an illustration of AR-ETC coated GRIN lenses 208
for use with optical fibers 206 and some of their uses;
[0025] FIG. 10 is a comparison of abrasion testing data for a glass
article having a PVD 8-10 nm ETC on 6 layer ARC (Nb2O5/SiO2)
coating and a glass article having only a spray coated ETC
coating;
[0026] FIG. 11 is a comparison of the abrasion reliability of a
glass article having a 6 layer PVD IAD-EB AR coating and an 8-10 nm
thermal deposited ETC coating on top of the AR coating relative to
a glass article having PVD AR coating deposited in a first
conventional coater and an ETC deposited in a second conventional
coater;
[0027] FIG. 12 is a graph of % Reflectance versus wavelength for
glass articles coated with an AR coating and an ETC coating after
6K, 7K, 8K and 9K wipes;
[0028] FIG. 13 is a graph of % Transmission versus wavelength for
glass articles with an AR coating and an ETC coating after 6K, 7K,
8K and 9K wipes;
[0029] FIG. 14 is a graph of Reflectance % versus wavelength and
illustrating the effect of the numbers of AR coating layers/periods
reflectance versus glass without an AR coating;
[0030] FIG. 15 illustrates an adjustable magnetic carrier 130a that
is substantially similar to the carrier 130 illustrated in FIG. 4A
and enables the use of a single carrier for different size
substrates;
[0031] FIG. 16A illustrates a prior art dome carrier 300 having a
plurality of openings 302 for placements of the lenses that are to
be coated;
[0032] FIG. 16B illustrates a lens 304 that has slipped off one
carrier 300 shoulder 306 inside opening 302, the lens 304 being in
a position to be broken as the carrier 300 cools;
[0033] FIG. 17A is an illustration of an embodiment of the coating
apparatus having a shadow mask covering a selected area of the dome
to improve the uniformity of the optical coating;
[0034] FIG. 17B is a graph of the Water Contact Angle versus
Abrasion Cycles illustrating the improvement that is obtained using
the mask as illustrated in FIG. 17A;
[0035] FIG. 18 is a simulation of the reflectance (y-axis) as a
function of wavelength (x-axis) for a glass substrate coated with a
6 layer AR coating (Nb.sub.2O.sub.5/SiO.sub.2) and an ETC coating
with the AR coating having a thickness variation of 2%; and
[0036] FIG. 19 graphically depicts the reflectance (y-axis) as a
function of wavelength for a plurality of actual samples coated
with a 6 layer AR coating (Nb.sub.2O.sub.5/SiO.sub.2) and an ETC
coating.
DETAILED DESCRIPTION
[0037] Reference will now be made in detail to embodiments of glass
articles coated with optical coatings and easy-to-clean coatings
and methods and apparatuses for forming the same, examples of which
are illustrated in the accompanying drawings. Whenever possible,
the same reference numerals will be used throughout the drawings to
refer to the same or like parts. One embodiment of a coating
apparatus is schematically depicted in FIG. 1A. The coating
apparatus generally includes a vacuum chamber with a magnetic dome
positioned therein. The coating apparatus also includes an e-beam
source, a thermal evaporation source and a plasma source. Glass
substrates to be coated can by magnetically attached to an
underside of the dome and coated with an optical coating and an ETC
coating using the e-beam source and the thermal evaporation source,
respectively. In embodiments, the plasma source may be used to
densify the deposited optical coating materials. Various
embodiments of apparatuses and methods for sequentially applying
optical coatings and ETC coatings to glass substrates will be
described in more detail herein with specific reference to the
appended drawings.
[0038] Herein the terms "process" and "method" may be used
interchangeably. Also herein the terms "shadowless" and "shadow
free" mean that the optical coating is uniformly deposited over the
entire surface of the glass substrate such that, when the glass
article with the coating deposited using the methods and
apparatuses described herein is viewed, the shadow that is observed
on glass articles having optical coating prepared using
conventional optical coating methods and apparatuses is not
observed. The shadow observed on conventionally coated glass
articles arises when areas of the substrate being coated shield the
surface of the substrate from the deposition of the optical coating
materials. These shadows are frequently observed adjacent to
elements that are used to hold the substrate being coated in place
during the coating process or are on the substrate carrier for
transport of the carrier and the elements being coated into and out
of the coater.
[0039] The terms "glass article" and "glass substrate" are used
herein interchangeably and generally refer to any glass item coated
using the methods and apparatuses described herein.
[0040] The present disclosure is directed to a process in which
both an optical coating, for example an AR coating, comprising
alternating layers of high refractive index and low refractive
index materials, and an ETC coating, for example a
perfluoroalkylsilane coating, can be applied to a glass substrate
in sequential steps (i.e., first applying the optical coating and
then applying the ETC coating over the optical coating) using
substantially the same procedure without exposing the article to
air or ambient atmosphere at any time during the application of the
optical coating and the ETC coating. A reliable ETC coating
provides lubrication to surface(s) of glass, transparent conductive
coatings (TCC), and optical coatings. In addition, the abrasion
resistance of glass and optical coatings will be more than 10 times
better than the conventional coating process or 100-1000 times
better than an AR coating without an ETC coating by using an
in-situ, one-step process in which the coatings are sequentially
applied, as graphically depicted in FIGS. 10, 11, and 17B. Using
such techniques, the ETC coating can be considered as part of the
optical coating during design and, as such, the ETC coating will
not change the desired optical performance. The glass articles
described herein are shadow free across the optically coated
surface of the glass.
[0041] A particular example of an in-situ process is a box coater
schematically depicted in FIG. 1A. The box coater is equipped with
an electron beam (e-beam) source for optical coatings, a thermal
evaporation source for the ETC coating material, and an ion beam or
a plasma source for surface cleaning before coating and optical
coating impaction during coating to increase the density of the
coating and the smoothness of the coating surface.
[0042] The optical coating is composed of high and median or low
refractive index materials. Exemplary high index materials having
an index of refraction n greater than or equal to 1.7 and less than
or equal to 3.0 include: ZrO.sub.2, HfO.sub.2, Ta.sub.2O.sub.5,
Nb.sub.2O.sub.5, TiO.sub.2, Y.sub.2O.sub.3, Si.sub.3N.sub.4,
SrTiO.sub.3, WO.sub.3; an exemplary median index material having an
index of refraction n greater than or equal to 1.5 and less than
1.7 is Al.sub.2O.sub.3; and an exemplary low index materials having
an index of refraction n greater than or equal to 1.3 and less than
or equal to 1.6) include: SiO.sub.2, MgF.sub.2, YF.sub.3,
YbF.sub.3. The optical coating stack that is deposited on a
substrate comprises at least one material/layer to provide a
specified optical function. In most cases, a high and a low index
material can be used to design a complex optical filter (including
AR coatings), for example, HfO.sub.2 as the high index material and
SiO.sub.2 as the low index material. TCC (two-component coating)
materials suitable for use in the coatings include ITO (indium tin
oxide), AZO (Al doped zinc oxide), IZO (Zn stabilized indium
oxides), In.sub.2O.sub.3, and similar binary and ternary oxide
compounds.
[0043] In embodiments, the optical coatings are applied to glass
substrates using PVD coating (sputtered or IAD-EB coated optical
coating with thermal evaporation of the ETC coating). PVD is a
"cold" process in which the substrate temperature is under
100.degree. C. As a result there is no degradation of the strength
of a chemically strengthened or tempered glass substrate to which
the coatings are applied.
[0044] In the embodiments described herein, the glass used to make
the shadow free, optical and ETC coated glass articles described
herein may be an ion-exchanged or non-ion-exchanged glass.
Exemplary glasses include silica glass, aluminosilicate glass,
borosilicate glass, aluminoborosilicate glass and soda lime glass.
The glass articles have a thickness in the range of 0.2 mm to 1.5
mm, and a length and width suitable for the intended purpose. Thus
the length and width of the glass article can range from that of a
cell phone to tablet computer, or larger.
[0045] The optical coatings referred to herein include
antireflection coatings (AR coatings), band-pass filter coatings,
edge neutral mirror coatings and beam splitters, multi-layer
high-reflectance coatings and edge filters as described in H. Angus
Macleod, "Thin Film Optical Filters", 3.sup.rd edition, Institute
of Physics Publishing. Bristol and Philadelphia, 2001. Applications
using such optical coatings include displays, camera lenses,
telecommunications components, instruments, medical devices,
photochromic and electrochromic devices, photovoltaic devices, and
other elements and devices.
[0046] Alternating layers of high and low refractive index
materials can be used to form optical coatings, such as
antireflective or anti-glare for ultraviolet ("UV"), visible
("VIS") and infrared ("IR") applications. The optical coatings can
be deposited using a variety of methods. Herein the PVD method
(i.e., ion-assisted, e-beam deposition) for depositing the optical
coatings is used as an exemplary method. The optical coatings
comprise at least one layer of a high index material H and at least
one layer of low index material L. Multilayer coatings consist of a
plurality of alternating high and low index layers, for example,
HL,HL,HL . . . , etc., or LH,LH,LH . . . , etc. One pair of HL
layers (or LH layers) is referred to as a "period" or a "coating
period." A medium index material M can be used in place of a low
index material in all or some of the low index layers. The term
"index," as used herein, refers to the index of refraction of the
material. In a multilayer coating the number of periods can range
widely depending on the function of the intended product. For
example, for AR coatings, the number of periods can be in the range
of greater than or equal to 2 and less than or equal to 20. An
optional final capping layer of SiO.sub.2 can also be deposited on
top of the AR coating as a final layer. Various techniques may be
used to deposit the ETC material on top of the optical coating
without exposing the optical coating to the ambient atmosphere
including, without limitation, thermal evaporation, chemical vapor
deposition (CVD) or atomic layer deposition (ALD).
[0047] The optical coatings deposited on the glass substrates
described herein may be multilayer optical coatings comprising at
least one period of a high refractive index material and a low
refractive index material. The high refractive index material may
be selected from ZrO.sub.2, HfO.sub.2, Ta.sub.2O.sub.5,
Nb.sub.2O.sub.5, TiO.sub.2, Y.sub.2O.sub.3, Si.sub.3N.sub.4,
SrTiO3, and WO.sub.3; however, it should be understood that other
suitable high refractive index materials may be used. The low
refractive index material may be selected from the group consisting
of SiO.sub.2, MgF.sub.2, YF.sub.3, and YbF.sub.3; however, it
should be understood that other suitable low refractive index
materials may be used. In some embodiments, the low refractive
index material may be replaced with a medium refractive index
material such as Al.sub.2O.sub.3 or another suitable medium
refractive index material.
[0048] In one embodiment, the present disclosure is directed to a
process in which, in a first step, a multilayer optical coating is
deposited on a glass substrate followed by a second step in which
the ETC coating is thermally evaporated and deposited in the same
chamber as the optical coating. In another embodiment a multilayer
optical coating is deposited on a glass substrate in one chamber
followed by the thermal evaporation and deposition of the ETC
coating on top of the multilayer coating in a second chamber, with
the provision that the transfer of the multilayer coated substrate
from the first chamber to the second chamber is carried out inline
in a manner such the substrate is not exposed to air between the
application of the multilayer coating and the ETC coating. The
coating techniques utilized may include, without limitation PVD,
CVD/PECVD, and ALD coating techniques. Depending on the size of the
chamber or chambers and the size of the substrates being coated,
one or a plurality of substrates can simultaneously be coated
within a single chamber.
[0049] The multilayer optical coatings are typically oxide coatings
in which the high index coating is a lanthanide series oxide such
as La, Nb, Y, Gd or other lanthanide metals, and the low index
coating is SiO.sub.2. The ETC materials may be, for example,
fluorinated silanes, typically alkyl perfluorocarbon silanes having
the formula (R.sub.F).sub.xSiX.sub.4-x, where R.sub.f is a linear
C.sub.6-C.sub.30 alkyl perfluorocarbon, X.dbd.Cl or --OCH.sub.3--
and x=2 or 3. The fluorocarbons have a carbon chain length in the
range of greater than or equal to 3 nm and less than or equal to 50
nm. The fluorocarbons can be obtained commercially from vendors
including, without limitation, Dow-Corning (for example
fluorocarbons 2604 and 2634), 3M Company (for example ECC-1000 and
4000). Daikin Corporation, Canon, Don (South Korea), Ceko (South
Korea), Cotec-GmbH (for example DURALON UltraTec) and Evonik.
[0050] FIG. 1A schematically depicts a coating apparatus 100 and
various operating elements of the apparatus according to one or
more embodiments disclosed herein. Coordinate axes are provided for
reference. In a frontal view x is from side-to-side (i.e., left to
right), y is from front-to-back (i.e., in and out of the page) and
z is from bottom-to-top. The coating apparatus 100 generally
comprises a vacuum chamber 102 having therein a magnetic rotatable
dome 110 with lip 161 (depicted in FIG. 3A) that is part of a frame
160 (further illustrated in FIG. 3B) that supports dome 110. The
dome includes a plurality of substrate carriers 130 magnetically
attached to an underside of the dome as illustrated in FIG. 2. A
plasma source 118 is located in the vacuum chamber 102 below the
dome 110 and is generally oriented to emit ions or plasma upwards,
towards the underside of the dome 110. The plasma source is used to
densify the optical coating materials as they are deposited and/or
after deposition thereby increasing the hardness of the finished
optical coating. Specifically, the ions or plasma emitted from the
plasma source impact the coating during deposition and/or after a
coating layer has been applied resulting in a densification of the
deposited material. Densifying the deposited optical coating
improves the abrasion resistance of the optical coating. For
example, in some embodiments, the deposited optical coating will
have at least double the abrasion reliability or abrasion
resistance of an optical coating deposited without the use of a
plasma source.
[0051] The coating apparatus further comprises an e-beam source 120
located below the dome 110 and an e-beam reflector 122 for
directing the e-beam from the e-beam source toward the optical
coating material being applied to the glass substrate to thereby
vaporize the optical material. A shadow mask 125 for enabling
uniform coating across the dome is located below the dome 110. The
shape and position of the shadow mask 125 are adjustable such that
the shadow mask is "tunable" to achieve a desired coating
uniformity. The shadow mask 125 is positioned on a support 125a
such that the position of the shadow mask 125 can be adjusted
vertically along the support 125a, as indicated by the dashed
double headed arrow. The position of the shadow mask 125 on the
support 125a can be adjusted as needed to prevent the shadow mask
from shielding the glass substrates located on the underside of the
dome 110 from the ions or plasma emitted from the plasma source 118
as the optical coating is applied. While FIG. 1A depicts a single
e-beam source 120, it should be understood that a plurality of
e-beam sources can be used to minimize the time to change from one
coating material to another, for example, changing from
Nb.sub.2O.sub.5 to SiO.sub.2 and back again, as required to deposit
the required number of individual layers of material for the
optical coating. For example, in some embodiments, the coating
apparatus may comprise greater than or equal to 2 e-beam sources
and less than or equal to 6 e-beam sources. When a plurality of
e-beam sources are used, each e-beam source may be directed to a
separate container (i.e., the boats 126, described further herein)
holding the material to be coated.
[0052] The coating apparatus 100 further comprises an optical
coating carrier 124 having a plurality of boats 126 which contain
the optical coating material. The boats 126 are separate source
containers used to contain the different materials used to deposit
the optical coating layer. The optical coating carrier 124 is
positioned in the vacuum chamber 102 such that an e-beam emitted
from the e-beam source 120 can be reflected by the e-beam reflector
122 onto the optical coating material contained in the boats 126,
thereby vaporizing the optical coating material. The boats 126
contain different optical coating materials so that only one type
of coating material (e.g., either a high refractive index, low
refractive index, or medium refractive index material), is applied
at one time. After the proper thickness of one coating material is
reached the lid (not depicted) of the corresponding boat is closed
and a lid to another boat containing a different coating material
to be applied is opened. In this manner the high refractive index
material, low refractive index material, or medium refractive index
material can be applied in an alternating manner to form an optical
coating material having the desired optical properties.
[0053] The coating apparatus 100 also comprises at least one
thermal evaporation source 128 for evaporating the ETC coating
material to facilitate depositing the coating material onto glass
substrates retained on the underside of the dome 110. The at least
one thermal evaporation source 128 is positioned in the vacuum
chamber 102 below the dome 110.
[0054] Still referring to FIG. 1A, the dome 110 is made of a light
weight material that is magnetic or contains a magnetic material,
for example and without limitation, aluminum containing iron or
another suitable magnetic material. The dome 110 can be rotated
either clockwise or counter-clockwise. At the top center of the
dome is an opening 164 (depicted in FIG. 3B) and a transparent
glass plate 116 is placed on the underside of the dome to cover the
opening. The transparent glass plate 116 may include an opening
116a as depicted in the enlarged view of the transparent glass
plate 116 depicted in FIG. 1B. A quartz monitor 114 is received in
and passes through the transparent glass plate 116. An optical
fiber 112 is positioned above the transparent glass plate 116, as
illustrated. The quartz monitor 114 controls the deposition rate of
the optical materials by feedback to the e-beam power supply so
that the deposition rate of the coating material is kept
substantially constant. The optical fiber 112 is positioned above
the transparent glass plate 116 to protect it from the deposition
materials within the vacuum chamber 102. The optical fiber measures
reflectance to determine when the deposition of each layer of the
coating material should be stopped because it has reached the
targeted design thickness.
[0055] FIG. 1C is an enlargement of the circled area of the
transparent glass plate 116 of FIG. 1A showing the relative
orientations of the optical fiber 112, the quartz monitor 114 and
the transparent glass plate 116. The quartz monitor 114 is
positioned in the middle of the transparent glass plate 116 and
passes through the opening 116a. The optical fiber 112 is
positioned to the side of the quartz monitor 114. Light transmitted
from the optical fiber 112 passes through the transparent glass
plate 116 and is reflected back as the surface of the transparent
glass plate is coated. The arrows adjacent to % R schematically
depict the reflectance of light from the surface 116b of the
transparent glass plate as the transparent glass plate is being
coated. The reflectance increases with the thickness of the
coatings applied to surface 116b of the transparent glass plate.
The light reflected from the surface 116b of the transparent glass
plate is directed back to an optical sensor (not shown) coupled to
a controller (not shown) of the e-beam source. The output of the
optical sensor (which is indicative of the thickness of the applied
optical coating and/or the ETC coating) is utilized by the
controller to determine the deposited thickness of the coatings. As
such, the reflected light can be used to control the deposited
thickness of an individual layer, a coating period, and the entire
optical coating as well as the deposited thickness of the ETC
coating.
[0056] The top of the dome 110 is attached to a vacuum shielded
rotation shaft 117 indicated by the dashed parallel lines. The
vacuum shielded rotation shaft 117 has a vacuum seal bearing 119
attached to the vacuum shielded rotation shaft for rotating the
vacuum shielded rotation shaft 117 and dome 110. Accordingly, it
should be understood that the vacuum shielded rotation shaft 117 is
vacuum sealed to the top of the dome 110. The vacuum shielded
rotation shaft 117 is driven by an external motor (not illustrated)
located external to the vacuum chamber 102. In an embodiment, the
dome 110 may be rotated at a rotation frequency in the range from
about 20 rpm to about 120 rpm. In another embodiment the rotation
frequency is in the range from about 40 rpm to about 83 rpm.
[0057] FIG. 2 schematically depicts a segment 110a of dome 110. As
shown in FIG. 2, a plurality of substrate carriers 130 are
magnetically attached to the dome 110. The substrate carriers 130
are utilized to secure glass substrates for coating in the coating
apparatus 100.
[0058] FIG. 3A is a drawing illustrating an oblique bottom-up side
view of a segment 110a of the dome 110 showing the lip 161 with a
plurality of substrate carriers 130 magnetically attached to the
dome 110. FIG. 3B is an illustration of the frame 160 that is used
to support a plurality of segments 110a. The frame 160 has an outer
lip 161 (as depicted in FIG. 3A), an inner rim (not numbered)
adjacent to opening 164 to which the vacuum shielded rotation shaft
117 can be attached (not illustrated) and a plurality of spokes 162
extending radially outward from the inner rim. The spokes 162 are
sufficiently wide to accommodate the side edges of the dome
segments as is illustrated at 168.
[0059] FIG. 17A is a simplified illustration of an alternative
embodiment of a coating apparatus for depositing an optical coating
and an ETC coating on a substrate. In this embodiment, the coating
apparatus includes a shadow mask 127 covering a selected area of
the dome to improve the uniformity of the optical coating deposited
on the substrate. The support for adjustably supporting the shadow
mask 127 is not depicted in FIG. 17A. In the coating apparatus of
FIG. 17A the plasma source is an ion source 118a. Since the ion
source 118a and the e-beam source 120 used to evaporate the optical
coating materials are located on different sides of the vacuum
chamber, the ion source is not shielded by the shadow mask, thereby
improving the efficacy of the ion source 118a in hardening the
deposited optical coating materials. The ion source is used to
densify the optical coating material to near bulk density thereby
increasing the hardness of the optical coating and improving the
abrasion reliability/abrasion resistance of the optical
coating.
[0060] Referring now to FIGS. 4A and 4B, a substrate carrier 130
made for carrying a single size substrate is schematically
depicted. As illustrated in FIG. 4A, the substrate carrier 130 has
a non-magnetic substrate carrier base 131, a plurality of magnets
134 for magnetically attaching the carrier to the dome 110 and for
off-setting the substrate carrier a distance from the dome. The
substrate carrier 130 also includes a plurality of pins 136 for
supporting a surface of a glass substrate 140 (illustrated in FIG.
4B) and a spring system 132. The spring system 132 generally
includes a retractable pin 138a that is held in place by a spring
133 (schematically depicted as an arrow) that biases the
retractable pin 138a in the direction indicated by the arrow, and a
plurality of fixed pins 138b. Pins 138a and 138b are used to hold a
glass substrate 140 (indicated by dashed line) in place on the
substrate carrier 130 while the glass substrate is being coated.
FIG. 4B is a side view of FIG. 4A illustrating a glass substrate
140 supported on pins 136 that extend into the nonmagnetic
substrate carrier base 131 for a distance from the substrate
carrier base surface 131a, a plurality of magnets 134 that extend
from the surface 131a of the substrate carrier 130 and through the
substrate for a distance beyond the base 131b, a side stopper 150
extending from of the nonmagnetic substrate carrier base 131 to a
distance from a top surface 140a of the glass substrate 140. The
side stopper 150 orients the glass substrate on the nonmagnetic
substrate carrier base 131 without affecting the application of the
coatings thereby preventing "shadows" on the surface of the glass
substrate. Specifically, the top surface 140a of the glass
substrate is the surface that will be coated with the optical
coating and the easy-to-clean coating. For a glass substrate having
a thickness of 5 mm, the top of side stopper 150 will be in the
range of 2-3 mm below the top surface 140a of the glass substrate
140. The opening (not numbered) in the middle of the substrate
carrier reduces the weight of the carrier.
[0061] Referring now to FIG. 15, an adjustable substrate carrier
130a similar to the fixed substrate carrier 130 illustrated in FIG.
4A is depicted. The adjustable substrate carrier 130a has a
non-magnetic substrate carrier base 131 which includes a plurality
of magnets 134 for attaching the adjustable substrate carrier to
the dome of the coating apparatus as described above. The
adjustable substrate carrier 130a also includes a plurality of pins
136 extending from the surface of the substrate carrier for
supporting a surface of a glass substrate positioned on the
adjustable substrate carrier 130a. A housing 138aa is positioned
proximate an edge of the adjustable substrate carrier 130a and
houses a retractable pin 138a (depicted partially extended from the
housing). The housing 138aa includes a spring (not shown)
positioned in the housing 138aa. The spring bias the retractable
pin 138a outward from the housing 138aa. The adjustable substrate
carrier 130a may optionally include side stoppers 150a (not
illustrated in FIG. 15) for orienting a glass substrate on the
adjustable substrate carrier 130a. In the embodiment depicted in
FIG. 15, the adjustable substrate carrier 130a further includes a
plurality of moveable pins 139 for holding an edge of the glass
substrate. The moveable pins 139 are positioned in tracks 137 to
facilitate adjustably positioning the moveable pins 139 relative to
the adjustable substrate carrier 130a. The moveable pins 139, in
combination with the retractable pin 138a enable the use of a
single carrier for different size substrates. The substrate or
substrates may be held by the pins, and any optional side stoppers
150a in the same manner as described above with respect to FIG. 4A
so that a shadow free coating is formed on the substrate.
[0062] As indicated in the foregoing paragraph, the substrate
carriers 130, 130a have a non-magnetic substrate carrier base 131
and a plurality of magnets 134 for holding the carrier to the dome
110 and for off-setting the carrier a distance from the dome. The
use of these magnetic carriers is an improvement over dome carriers
that are used in the coating of optical elements such as lenses.
For example, FIG. 16A illustrates a conventional dome carrier 300
having a plurality of openings 302 for positioning lenses that are
to be coated. When the lenses are coated they are inserted into an
opening in the carrier. However in this conventional design it is
difficult to uniformly coat both the inside and outside of the
dome. It is also difficult to keep the coating material away from
surfaces of the lenses that are not to be coated. In addition, the
part being coated can move with respect to the opening in the dome
as the dome heats up, resulting in breakage as the dome cools after
coating. For example, FIG. 16B illustrates a lens 304 that has
slipped off one support shoulder 306 inside an opening 302 of the
dome carrier. As is easily seen, if the carrier cools faster than
the lens 304, the contraction of the carrier can cause the lens to
break. In the present application, since the substrate carrier is
off-set a distance from the dome by the magnets that hold the
carrier to the dome, heat transfer is minimized and breakage does
not occur as the dome cools. In addition, only one side of the
glass article being coated is subjected to the coating materials
due to the proximity of the carrier/substrate combination to
interior surface of the dome. As a result the difficulties
mentioned above in conventional dome carriers can be avoided.
[0063] Referring now to FIG. 5, a cross section of the pins 138a
and 138b against which a glass substrate is held by the force
exerted against it by the retractable pin 138a is schematically
depicted. The glass substrate has a shaped edge which fits between
the head 138h of pins 138a and 138b and the remainder of the body
of the pin. The edge of the glass substrate may be chamfered as
illustrated at 141, rounded, bull nosed or otherwise contoured.
When the glass substrate 140 is engaged with the pins 138a, 138b,
the top 140a of the glass substrate is 2-3 mm below the top of the
pin 138a or 138b. In this figure, reference numeral 140b indicates
the bottom surface of glass substrate 140.
[0064] Referring now to FIG. 4A and FIG. 6, a glass substrate 140
is loaded onto the substrate carrier 130 and the combination of the
glass substrate 140 and the substrate carrier 130 is magnetically
attached to the underside of dome 110. When the substrate carrier
130 with glass substrate 140 (dashed line) is loaded onto the dome
110 for coating, the retractable pin 138a is positioned
perpendicular to the rotation direction of the dome 110 as
indicated by the arrow; that is, the pin is closer to the opening
at the top T of the dome 110 than the fixed pins 138b. When the
substrate carrier is so positioned the optical coating is uniformly
deposited over the entire surface of the glass substrate 140 to
form a "shadowless" or "shadow free" coated glass substrate 140.
These terms, "shadowless" and "shadow free," refer to the fact that
if: [0065] (1) the retractable pin 138a is not positioned on dome
110 as described and illustrated in FIG. 6, and [0066] (2) the top
surface 140a of glass substrate 140 is less than 1 mm below head
138h of pin 138a, and [0067] (3) the top of side stoppers 150 are
not lower than the top surface 140a; then the deposition of the
optical coating will be non-uniform in the areas where these
elements and other elements holding the substrate are located. As a
result, the optical coating will be thinner near these elements and
thicker as one moves away from them. The result is a non-uniform
optical deposition or "shadow" that can be noticed by a user of the
articles. Such shadows can be avoided using the apparatus and
methods described in this disclosure.
[0068] Referring again to FIG. 1A, once the adjustable substrate
carrier 130a is magnetically attached to the dome 110, the
materials for applying the optical coating to the glass substrate
are loaded into separate boats 126 (i.e., separate source
containers) of the optical coating carrier 124. As noted
hereinabove, the optical coating is composed of alternating layers
of high and low refractive index materials or alternating layers of
high and middle refractive index materials. Exemplary high index
materials having an index of refraction n greater than or equal to
1.7 and less than or equal to 3.0 are: ZrO.sub.2, HfO.sub.2,
Ta.sub.2O.sub.5, Nb.sub.2O.sub.5, TiO.sub.2, Y.sub.2O.sub.3,
Si.sub.3N.sub.4, SrTiO.sub.3, WO.sub.3; an exemplary medium index
material having an index of refraction n greater than or equal to
1.5 and less than 1.7 is Al.sub.2O.sub.3; and an exemplary low
index materials having an index of refraction n greater than or
equal to 1.3 and less than or equal to 1.6) are: SiO.sub.2,
MgF.sub.2, YF.sub.3, YbF.sub.3. In some embodiments, medium
refractive index material may be used to form the low refractive
index layer L. Accordingly, in some embodiments, the low index
material may be selected from SiO.sub.2, MgF.sub.2, YF.sub.3,
YbF.sub.3 and Al.sub.2O.sub.3. In an exemplary embodiment, the
optical coating materials are oxide coatings in which the high
index coating is a lanthanide series oxide such as La, Nb, Y, Gd or
other lanthanide metals, and the low index coating is SiO.sub.2. In
addition, the material for applying the easy-to-clean (ETC) coating
is loaded in to the at least one thermal evaporation source 128. As
noted hereinabove the ETC materials may be, for example,
fluorinated silanes, typically alkyl perfluorocarbon silanes having
the formula (R.sub.F).sub.xSiX.sub.4-x, where R.sub.f is a linear
C.sub.6-C.sub.30 alkyl perfluorocarbon, X.dbd.Cl or --OCH.sub.3--
and x=2 or 3. The fluorocarbons have a carbon chain length in the
range of greater than or equal to 3 nm and less than or equal to 50
nm.
[0069] Once the coating materials are loaded, the vacuum chamber
102 is sealed and evacuated to a pressure less than or equal to
10.sup.-4 Torr. The dome 110 is then rotated in the vacuum chamber
by rotating the vacuum shielded rotation shaft 117. The plasma
source 118 is then activated to direct ions and/or plasma towards
the glass substrates positioned on the underside of the dome 110 to
densify the optical coating materials as they are applied to the
glass substrate. Thereafter the optical coating and ETC coating are
sequentially applied to the glass substrate. The optical coating is
first applied by vaporizing the optical materials positioned in the
boats 126 of the optical coating carrier 124. Specifically, the
e-beam source 120 is energized and emits a stream of electrons
which are directed onto the boats 126 of the optical coating
carrier 124 by the e-beam reflector 122. The vaporized material is
deposited on the surface of the glass substrates as the glass
substrates are rotated with the dome 110. The rotation of the dome
110, in conjunction with the shadow mask 125 and the orientation of
the glass substrates on the substrate carriers 130, allows the
optical coating materials to be uniformly coated onto the glass
substrate carriers, thereby avoiding "shadows" on the coated
surface of the glass substrate. As described hereinabove, the
e-beam source 120 is utilized to sequentially deposit layers of
high refractive index material and low refractive index material or
medium refractive index material to achieve an optical coating
having the desired optical properties. The quartz monitor 114 and
the optical fiber 112 are utilized to monitor the thicknesses of
the deposited materials and thereby control the deposition of the
optical coating, as described herein.
[0070] Once the optical coating has been applied to the glass
substrate to the desired thickness using the desired coating
material(s), optical coating ceases and the ETC coating is applied
over the optical coating by thermal evaporation as the glass
substrate rotates with the dome 110. Specifically, the ETC material
positioned in the at least one thermal evaporation source 128 is
heated, thereby vaporizing the ETC material in the vacuum chamber
102. The vaporized ETC material is deposited on the glass substrate
by condensation. The rotation of the dome 110 in conjunction with
the orientation of the glass substrates on the substrate carriers
130 facilitates uniformly coating the ETC materials onto the glass
substrate. The quartz monitor 114 and the optical fiber 112 are
utilized to monitor the thicknesses of the deposited materials and
thereby control the deposition of the ETC coating, as described
herein.
[0071] FIGS. 7 (a)-(c) are a schematic representation of the
fluorinated silane grafting reactions with glass or an oxide
optical coating (i.e., the reaction between the ETC coating
material and the glass or an oxide optical coating). FIG. 7c
illustrates that, when fluorocarbon trichlorosilane is grafted to
the glass, the silane silicon atom can be either (1) triply bonded
(three Si--O bonds) to the glass substrate or the surface of a
multilayer oxide coating on the substrate or (2) doubly bonded to a
glass substrate and have one Si--O--Si bond to an adjacent
R.sub.FSi moiety. The ETC coating process time is very short and
can be used to provide an ETC coating having a thickness in a range
from greater than or equal to 3 nm and less than or equal to 50 nm
over the freshly applied optical coating without breaking vacuum
(i.e., without exposing the optical coating to ambient atmosphere).
In the coating process described herein the ETC material is
evaporated from a single source. However it should be understood
that the ETC material may also be simultaneously evaporated from a
plurality of sources. For example, it has been found that 2-5
separate ETC material sources may be advantageous. Specifically,
the use of a plurality of sources containing the ETC material
results in a more uniform ETC coating and can enhance coating
durability. The term "sources" as used herein, refers to the
containers or crucibles from which the ETC material is thermally
evaporated.
[0072] In the embodiments described herein, an SiO.sub.2 layer is
generally applied as a capping layer for optical coatings. The
SiO.sub.2 layer is generally deposited as part of the optical
coating prior to the deposition of the ETC coating. This SiO.sub.2
layer provides a dense surface for grafting and crosslinking of
silicon atoms of the ETC coating as these layers were deposited at
high vacuum (10.sup.-4-10.sup.-6 Torr) without the presence of free
OH. Free OH, for example a thin layer of water on the glass or AR
surface, is detrimental during ETC material deposition because the
OH prevents the silicon atoms in the ETC material from bonding with
the oxygen atoms of metal oxide or silicon oxide surfaces, that is,
the optical coating surface. When the vacuum in the deposition
apparatus is broken, that is, the apparatus is opened to the
atmosphere, air from the environment, which contains water vapor,
is admitted and the silicon atoms of the ETC coating react with the
optical coating surface to create at least one chemical bond
between the ETC silicon atom and surface oxygen atom, and release
alcohol or acid once exposed to air. Since the ETC coating material
typically contains 1-2 fluorinated groups and 2-3 reactive groups
such as CH.sub.3O-groups, the ETC coating is capable of bonding to
2-3 oxygen atoms at the optical coating surface, or crosslinking
with another coating molecule as shown in FIG. 7(c), to create a
strongly bonded ETC coating. The PVD deposited SiO.sub.2 surface is
pristine and has a reactive surface. For example, for a PVD
deposited SiO.sub.2 cap layer, the binding reaction has a much
lower activation energy, as is illustrated in FIG. 8, than on a
glass that has a complicated surface chemistry, has an
environmental contaminant on it or, has a water layer on the glass
surface.
[0073] Thus, once the ETC coating has been applied over the optical
coating, the glass substrate with the optical coating and the ETC
coating is removed from the chamber and allowed to cure in air. If
allowed to cure simply by sitting at room temperature.
(approximately 18-25.degree. C., Relative Humidity (RH) 40%) the
curing will take 1-3 days. Elevated temperatures may be utilized to
expedite curing. For example, in one embodiment, the ETC coated
article may be heated to a temperature of 80-100.degree. C. for a
time period from about 10 minutes to about 30 minutes at a RH in
the range of greater than 50% and less than 100%. Typically the
relative humidity is in the range of 50-85%.
[0074] Once the ETC coating has been cured, the surface of the
coating is wiped with a soft brush or an isopropyl alcohol wipe to
remove any ETC material that has not bonded to the optical
coating.
[0075] The methods and apparatuses described herein may be used to
produced coated glass articles, such as coated glass substrates,
which have both an optical coating (such as an AR coating or a
similar optically functional coating) and an ETC coating positioned
over the optical coating. Utilizing the methods and apparatuses
described herein, the coated glass articles are generally shadow
free across the optically coated surface of the glass article. In
embodiments, the optical coating applied to the glass article may
have a plurality of periods consisting of a layer of high
refractive index material H having an index of refraction n greater
than or equal to 1.7 and less than or equal to 3.0, and a layer of
low refractive index material L having an index of refraction n
greater than or equal to 1.3 and less than or equal to 1.6. The
layer of high refractive index material may be the first layer of
each period and the layer of low refractive index material L may be
the second layer of each period. Alternatively, the layer of low
refractive index material may be the first layer of each period and
the layer of high refractive index material H may be the second
layer of each period. In some embodiments, the number of coating
periods in the optical coating may be greater than or equal to 2
and less than or equal to 1000. The optical coating may further
include a capping layer of SiO.sub.2. The capping layer may be
applied on over one or a plurality of periods and may have a
thickness in the range greater than or equal to 20 nm and less than
or equal to 200 nm. In the embodiments described herein, the
optical coating may have a thickness in the range from greater than
or equal to 100 nm to less than or equal to 2000 nm. However,
greater thicknesses are possible depending on the intended use of
the coated article. For example, in some embodiments, the optical
coating thickness can be in the range of 100 nm to 2000 nm. In some
other embodiments, the optical coating thickness can be in the
range of 400 nm to 1200 nm or even in the range from 400 nm to 1500
nm.
[0076] The thickness of each of the layers of high refractive index
material and low refractive index material may be in a range from
greater than or equal to 5 nm and less than or equal to 200 nm. The
thickness of each of the layers of high refractive index material
and low refractive index material may be in a range from greater
than or equal to 5 nm and less than or equal to 100 nm. As will be
described further herein, the coated glass articles exhibit an
improved resistance to abrasion to the specific coating methods and
techniques utilized herein. The degradation of the coatings applied
to the glass article may be assessed by the water contact angle
following exposure of the glass coating to abrasion testing. The
abrasion testing was carried out by rubbing grade 0000# steel wool
across the coated surface of the glass substrate under a 10 kg
normal load. The abraded area is 10 mm.times.10 mm. The frequency
of abrasion is 60 Hz and the travel distance of the steel wool is
50 mm. The abrasion testing is performed at a relative humidity
RH<40%. In the embodiments described herein, glass articles have
a water contact angle of at least 75.degree. after 6,000 abrasion
cycles. In some embodiments, the glass articles have a water
contact angle of at least 105.degree. after 6,000 abrasion cycles.
In still other embodiments, the glass articles have a water contact
angle of greater than 90.degree. after 10,600 abrasion cycles.
[0077] The resistance of the glass article to abrasion and
degradation may also be assessed by the length of scratches present
on the glass article following abrasion testing. In embodiments
described herein, the coated glass articles have a surface scratch
length of less than 2 mm following 8000 abrasion cycles.
[0078] Moreover, the resistance of the glass article to abrasion
and degradation may also be assessed by the change in the
reflectance and/or transmittance of the glass article following
abrasion testing, as will be described in more detail herein. In
some embodiments, a % Reflectance of the glass article after at
least 8,000 abrasion/wiping cycles is substantially the same as the
% Reflectance of an unabraded/unwiped glass article. In some
embodiments, the % Transmission of the glass article after at least
8,000 abrasion/wiping cycles is substantially the same as the %
Transmission of an unabraded/unwiped glass article.
[0079] The deposition methods described herein may be used to
produce a shadow free optical coating. This means that mean that
the optical coating is uniformly deposited over the entire coated
surface of the glass substrate. In embodiments of the coated glass
substrates described herein, the variation in a thickness of the
optical coating across the coated surface of the glass substrate is
less than 4%. For example, in some embodiments, the variation in
the thickness of the optical coating across the coated surface of
the glass substrate is less than or equal to 3%. In some other
embodiments the variation in the thickness of the optical coating
across the coated surface of the glass substrate is less than or
equal to 2%. In still other embodiments, the variation in the
thickness of the optical coating across the coated surface of the
glass substrate is less than or equal to 1%.
[0080] Ion-assisted electron-beam deposition provides a unique
advantage for coating small and medium size glass substrates, for
example those having facial dimensions in the range of
approximately 40 mm.times.60 mm to approximately 180 mm.times.320
mm, depending on chamber size. Ion assisted coating process
provides a freshly deposited optical coating on the glass surface
that has low surface activation energy with regard to the
subsequent application of the ETC coating since there is no surface
contamination (water or other environmental) that might impact ETC
coating performance and reliability. The application of the ETC
coating directly after completion of the optical coating improves
crosslinking between two fluorocarbon functional groups, improves
wear resistance, and improves contact angle performance (higher
oleophobic and hydrophobic contact angles) following thousands of
abrasion cycles applied to the coating. In addition, ion-assisted
e-beam coating greatly reduces coating cycle time to enhance coater
utilization and throughput. Further, no post deposition heat
treatment or UV curing of the ETC coating is required due to lower
activation energy of the optical coating surface which makes the
process compatible with post ETC processes in which heating is not
permitted. Using the Ion-assisted e-beam PVD processes described
herein, the ETC material can be coated on selected regions to avoid
contamination to other locations of substrate.
Example 1
[0081] A 4-layer
SiO.sub.2/Nb.sub.2O.sub.5/SiO.sub.2/Nb.sub.2O.sub.5/substrate AR
optical coating was deposited on sixty (60) pieces of Gorilla.TM.
Glass (commercially available from Corning Incorporated) with
dimension (Length, Width, Thickness) of approximately 115 mm
L.times.60 mm W.times.0.7 mm T. The coating was deposited using the
methods described herein. The AR coating had a thickness of
approximately 600 nm. After deposition of the AR coating an ETC
coating was applied on top of the AR coating by thermal evaporation
using perfluoroalkyl trichlorosilanes having a carbon chain length
in the range of 5 nm to 20 nm (Optool.TM. fluoro coating, Daikin
Industries was used as an exemplary species). The deposition of the
AR and ETC coating was carried out in a single chamber coating
apparatus as illustrated in FIG. 1A. After the AR coating was
deposited the AR coating source material was shut off and the ETC
material was thermally evaporated and deposited on the AR coated
glass. The coating process was 73 minutes including parts
loading/unloading. Subsequently, after the ETC coating was cured,
water contact angles were determined after the surface was abraded
using various abrasion cycles as indicated in Table 1. The abrasion
testing was conducted with #0 steel wool and a 1 kg weight load.
The data in Table 1 indicates that the sample has very good wear
and hydrophobic properties. The coating order and layer thickness
for a 6-layer Nb.sub.2O.sub.5/SiO.sub.2 coating on a glass
substrate is given in Table 2.
TABLE-US-00001 TABLE 1 Water contact angle abrasion test results
Sample Before Abrasion 3.5K Abrasion 4.5K Abrasion 5.5K Abrasion 1
113.8 114.2 116.1 109.9 107.2 108.5 92.6 103.4 96.3 69.5 85.5
70.5
TABLE-US-00002 TABLE 2 Layer Number Material Thickness Range, nm 6
SiO.sub.2 80-120 5 Nb.sub.2O.sub.5 75-90 4 SiO.sub.2 5-20 3
Nb.sub.2O.sub.5 40-80 2 SiO.sub.2 24-40 1 Nb.sub.2O.sub.5 10-20
Substrate Glass NA
Example 2
[0082] In this Example the same fluoro-coating used in Example 1
was coated on a GRIN-lens for optical connectors, as is illustrated
in FIG. 9, for use on optical fibers 206 used in laptop computers.
Numeral 200 and arrow point to of a selective region of the GRIN
lenses 208 for placing an ETC coating on top of an 850 nm AR
coating to provide particle and wear resistance. Numeral 202
illustrates connecting an optical fiber to a laptop or tablet
device, and numeral 204 illustrates the use of a coated fiber optic
to connect a laptop to a media dock.
[0083] FIG. 10 is abrasion testing data on a glass article having
an 8-10 nm thermally deposited on a ETC coating on a 6 layer AR
coating consisting of substrate/(Nb2O5/SiO2)3, ETC/6L-AR coating,
versus a glass sample with only the spray coated ETC coating. The
glass was 0.7 mm thick Corning code 2319 glass which is
commercially available, chemically tempered (ion-exchanged) glass.
The abrasion testing was carried out under following conditions:
grade 0000# steel wool, 10 kg load on 10 mm.times.10 mm area, 60
Hz, 50 mm travel distance, RH<40%. A water contact angle greater
than 75 degrees is the criterion for judging coating failure. It
was found that glass having an AR coating without the ETC coating
was scratch damaged after only 10-20 wiping cycles. FIG. 10 shows
that both glass samples start out with a water contact angle of
120.degree., and, after 6000 abrasion cycles the glass sample with
only the ETC coating had a water contact angle of 80.degree.
whereas the glass sample made as described herein, ETC/6 layer-AR
coating, had a water contact angle of at least 105.degree.. After
10,000 abrasion cycles the water contact angle of the ETC/6
layer-AR coating coated article was greater than 90.degree.. The
test clearly indicates that a glass article having an ETC coating
deposited on top of an AR coating has a much greater degree of
scratch resistance than a glass article have only an ETC coating
applied to the glass.
[0084] FIG. 11 is a comparison of the abrasion durability of a (1)
a glass article with a 6 layer PVD IAD-EB AR coating and an 8-10 nm
thermally deposited ETC coating on top of the AR coating (indicated
by numeral 220 and the diamond data marker), versus a commercially
available glass article (indicated by numeral 222 and the square
data marker) having a PVD-AR coating deposited by a first
commercial coater apparatus and an ETC deposited in a second
chamber by a commercial process such as dipping or spraying. Both
coatings were deposited on samples of the same chemically tempered
(ion-exchanged) 0.7 mm thick Corning Code 2319 glass. Glass article
220 was coated according to the methods described herein. The
commercially available glass article was coated by a commercial
coating vendor. The abrasion durability was carried out at a
relative humidity of 40%. At the point indicated by arrow 224, only
short, shallow scratches, less than 2 mm long, appeared after 8,000
cycles. In contrast, at the point indicated by arrow 226 deep, long
scratches, greater than 5 mm long, appeared after only 200 wipes.
The test results indicate that the abrasion durability of AR
coating-ETC glasses coated as described herein is at least 10 times
greater than the durability of commercially available products.
[0085] FIG. 17B graphically depicts the Water Contact Angle versus
Abrasion Cycles illustrating the improvement that is obtained using
a coating apparatus configured as depicted in FIG. 17A. The water
contact angle results can be compared to those of FIGS. 10 and 11.
The data in FIG. 17B show that, after 10,000 abrasion cycles, all
the substrates illustrated in FIG. 17B have a water contact angle
of greater than 110.degree., and substantially all of the
substrates had a water contact angle of 112.degree. or higher. In
contrast, the data of FIGS. 10 and 11 indicate that the water
contact angles were less than 100.degree. after 10,000 abrasion
cycles. Further, the data in FIG. 17B indicates that for substrates
that have been subjected to 12,000 abrasion cycles, the water
contact angles of the substrates is greater than 106.degree..
[0086] FIG. 12 is a graph of % Reflectance versus wavelength, where
Reflectance means the percentage of light reflected from the
surface of the coated glass article coated with an AR coating and
ETC coating as described herein. A new (unabraded or unwiped)
article was used for each wiping test. The abrasion/wiping was
carried out under following conditions: grade 0000# steel wool, 10
kg load on 10 mm.times.10 mm area, 60 Hz, 50 mm travel distance,
RH<40%. Reflectance was measured after 6K, 7K, 8K and 9K
abrasions. The graph indicates that new articles and articles wiped
up to 8K wipes have substantially the same reflectance. After 8K
wipes the reflectance increases. This reflection increase is
believed due to slight abrasion of the glass surface as a result of
a large number of wipes. In the graph the letter "A" means "After
Wiping" and the letter "B" means "Before Wiping" (zero wipes). The
letter "K" means "kilo" or "thousand".
[0087] FIG. 13 is a graph of % Transmission versus wavelength. The
testing was performed on coated glass articles coated with an AR
coating and ETC coating as described herein. A new (unabraded or
unwiped) article was used for each wiping test. The transmission
test used the same articles as the reflectance test. The graph
indicates that new articles and articles wiped up to 8K wipes have
substantially similar transmissions, the transmission being the
range of 95-96%. After 8K wipes the transmission falls to
approximate 92% over the entire wavelength range. This transmission
decrease is believed due to slight abrasion of the glass surface as
a result of a large number of wipes. In the graph the letter "A"
means "After wiping" and the letter "B" means "Before wiping" (zero
wipes). The letter "K" means "kilo" or "thousand"
[0088] The data in FIGS. 12 and 13 indicate that the optical
coating on the glass articles is highly durable in addition to
having excellent water contact angle retention as is shown by FIGS.
10 and 11.
[0089] FIG. 14 is a graph of Reflectance % versus wavelength
illustrating the effect of the numbers of AR coating layers/periods
on reflectance relative to glass without an AR coating. Curve 240
represents uncoated ion-exchanged glass, Corning Code 2319. Curve
244 is a 2-layer, or 1-period, coating consisting of
SiO.sub.2/Nb.sub.2O.sub.3. Curves 246 and 248 are 4-layer (2
periods) and 6-layer (3 periods) coatings consisting of
SiO.sub.2/Nb.sub.2O.sub.3 layer pairs. Curve 242 is a 1-layer
coating of Nb.sub.2O.sub.3. The data indicates that increasing the
AR coating stack number (layers/periods) will broaden the utility
of the AR coating spectral range and will also decrease the
Reflectance %.
Example 3
[0090] FIG. 18 is a computer simulation of the reflectance (y-axis)
as a function of wavelength (x-axis) for a glass substrates coated
with a 6 layer AR coating (Nb.sub.2O.sub.5/SiO.sub.2) and an ETC
coating. The AR coating was simulated with a thickness variation of
2%. Accordingly, the resultant reflectance profile simulates the
reflectance of a 6 layer AR coating (Nb.sub.2O.sub.5/SiO.sub.2) and
an ETC coating where the ETC coating has a thickness variation of
2%. FIG. 19 graphically depicts the reflectance (y-axis) as a
function of wavelength for a plurality of actual samples coated
with a 6 layer AR coating (Nb.sub.2O.sub.5/SiO.sub.2) and an ETC
coating using the methods and apparatuses described herein. As
depicted in FIG. 19, the reflectance profile of the actual samples
is similar to the reflectance profile of the simulated samples,
thus indicating that the samples coated using the methods described
have an optical coating in which the thickness variation of the
optical coating across the coated substrate (i.e., from edge to
edge of the coated surface) is less than 3%.
[0091] The AR/ETC coating described herein can be utilized in many
commercial articles. For example, the resulting coating can be used
to make televisions, cell phones, electronic tablets, and book
readers and other devices readable in sunlight. The AR/EC coatings
also have utility in antireflection beamsplitters, prisms, mirrors
and laser products; optical fibers and components for
telecommunication; optical coatings for use in biological and
medical applications; and for anti-microbial surfaces.
[0092] In a first aspect, the disclosure provides a method for
making a glass article having an optical coating and an
easy-to-clean (ETC) coating on top of the optical coating. The
method includes: providing a coating apparatus having a vacuum
chamber for deposition of an optical coating and an ETC coating;
providing a magnetic rotatable dome within said vacuum chamber for
magnetically positioning a magnetic substrate carrier for receiving
a glass substrate thereon that is to be coated; providing within
said vacuum chamber source materials for the optical coating and
source materials for the ETC coating; loading the glass substrate
on the magnetic substrate carrier and magnetically attaching the
magnetic substrate carrier having the glass substrate thereon to
the magnetic rotatable dome; evacuating the vacuum chamber;
rotating the magnetic rotatable dome and depositing an optical
coating on the glass substrate; rotating the magnetic rotatable
dome and depositing the ETC coating on top of the optical coating
following deposition of the optical coating, wherein the optical
coating is not exposed to ambient atmosphere prior to the
deposition of the ETC coating; and removing the glass substrate
having the optical coating and the ETC coating from the vacuum
chamber to obtain a glass substrate having a shadow-free optical
coating deposited on the glass substrate and the ETC coating
deposited on the optical coating.
[0093] In a second aspect, the disclosure provides the method of
the first aspect further comprising curing the ETC coating.
[0094] In a third aspect, the disclosure provides the method
according to either of the first or second aspects wherein the ETC
coating is cured in air at room temperature.
[0095] In a fourth aspect, the disclosure provides the method
according to either of the first or second aspects, wherein the ETC
coating is cured by heating the ETC coating.
[0096] In a fifth aspect, the disclosure provides the method
according to any of the first through fourth aspects, wherein the
vacuum chamber is evacuated to a pressure of less than or equal to
10.sup.-4 Torr.
[0097] In a sixth aspect, the disclosure provides the method
according to any of the first through fifth aspects, wherein the
method further comprises densifying the optical coating as the
optical coating is deposited.
[0098] In a seventh aspect, the disclosure provides the method
according to any of the first through sixth aspects, wherein the
vacuum chamber contains at least one e-beam source for vaporizing
the source materials for the optical coating.
[0099] In an eighth aspect, the disclosure provides the method
according to the seventh aspect, wherein the at least one e-beam
source comprises greater than or equal to 2 and less than or equal
to 6 e-beam sources and an e-beam from each source is directed to a
separate container holding a material being coated.
[0100] In a ninth aspect, the disclosure provides the method
according to any of the first through eighth aspects, wherein the
magnetic substrate carrier is selected from the group consisting of
a fixed magnetic substrate carrier and an adjustable magnetic
substrate carrier. In a tenth aspect, the disclosure provides the
method according to any of the first through ninth aspects, wherein
depositing the optical coating comprises depositing a multilayer
optical coating comprising at least one period of a high refractive
index material and a low refractive index material, wherein: the
high refractive index material is selected from the group
consisting of ZrO.sub.2, HfO.sub.2, Ta.sub.2O.sub.5,
Nb.sub.2O.sub.5, TiO.sub.2, Y.sub.2O.sub.3, Si.sub.3N.sub.4,
SrTiO.sub.3, WO.sub.3; and the low refractive index material is
selected from the group consisting of SiO.sub.2, MgF.sub.2,
YF.sub.3, YbF.sub.3 and Al.sub.2O.sub.3.
[0101] In an eleventh aspect, the disclosure provides the method
according to any of the first through tenth aspects, wherein the
glass substrate is formed from ion-exchanged silica glass,
non-ion-exchanged silica glass, aluminosilicate glass, borosilicate
glass, aluminoborosilicate glass, or soda lime glass.
[0102] In a twelfth aspect, the disclosure provides the method
according to any of the first through eleventh aspects, wherein the
source material for the ETC coating is a alkyl perfluorocarbon
silane of formula (R.sub.F).sub.xSiX.sub.4-x, where R.sub.F is a
linear C.sub.6-C.sub.30 alkyl perfluorocarbon, X.dbd.Cl or
--OCH.sub.3-- and x=2 or 3.
[0103] In a thirteenth aspect, the disclosure provides a magnetic
substrate carrier for holding a substrate during a coating process.
The magnetic substrate carrier comprises a non-magnetic substrate
carrier base; a plurality of magnets attached to the non-magnetic
substrate carrier base; a plurality of pins for supporting a
surface of a glass substrate positioned on the magnetic substrate
carrier; a spring system comprising a retractable pin held in place
by a spring that retracts the retractable pin, the retractable pin
being extendable in a direction opposite the spring, a plurality of
fixed pins, and a plurality of side stoppers extending from the
non-magnetic substrate carrier base for a distance such that, when
the glass substrate is positioned on the plurality of pins, tops of
the plurality of side stoppers are below a top surface of the glass
substrate.
[0104] In a fourteenth aspect, the disclosure provides a magnetic
substrate carrier for holding substrates during a coating process.
The magnetic substrate carrier comprises: a non-magnetic carrier
base; a plurality of magnets attached to the non-magnetic carrier
base; a plurality of pins for supporting a surface of a glass
substrate; a housing with a retractable pin disposed in the
housing, wherein the retractable pin is held in place by a spring,
the retractable pin being outwardly biased from the housing;
optional stoppers; and a plurality of movable pins for holding an
edge of a glass substrate.
[0105] In a fifteenth aspect, the disclosure provides a glass
article comprising an optical coating and an easy-to-clean coating
on top of the optical coating, the glass article being shadow free
across an optically coated surface of the glass article, wherein:
the optical coating comprises a plurality of periods consisting of
a layer of high refractive index material H having an index of
refraction n greater than or equal to 1.7 and less than or equal to
3.0, and a layer of low refractive index material L having an index
of refraction n greater than or equal to 1.3 and less than or equal
to 1.6, the layer of high refractive index material H being a first
layer of each period and the layer of low refractive index material
L being a second layer of each period; and an SiO.sub.2 capping
layer having a thickness in a range greater than or equal to 20 nm
and less than or equal to 200 nm applied on top of the plurality of
periods.
[0106] In a sixteenth aspect, the disclosure provides the glass
article of the fifteenth aspect, wherein a number of coating
periods is in a range from greater than or equal to 2 and less than
or equal to 1000.
[0107] In a seventeenth aspect, the disclosure provides the glass
article of any of the fifteenth through sixteenth aspects, wherein
the optical coating has a thickness in a range from greater than or
equal to 100 nm to less than or equal to 2000 nm.
[0108] In an eighteenth aspect, the disclosure provides the glass
article of any of the fifteenth through seventeenth aspects,
wherein a number of coating periods is in a range from greater than
or equal to 2 and less than or equal to 20, and a thickness of each
layer of high refractive index material H and low refractive index
material L is in a range from greater than or equal to 5 nm and
less than or equal to 200 nm.
[0109] In a nineteenth aspect, the disclosure provides the glass
article of any of the fifteenth through seventeenth aspects,
wherein a number of coating periods is in a range from greater than
or equal to 2 and less than or equal to 20, and a thickness of each
layer of high refractive index material H and the low refractive
index material L is in a range from greater than or equal to 5 nm
and less than or equal to 100 nm.
[0110] In a twentieth aspect, the disclosure provides the glass
article of any of the fifteenth through nineteenth aspects, wherein
the layer of high refractive index material H is selected from the
group consisting of ZrO.sub.2, HfO.sub.2, Ta.sub.2O.sub.5,
Nb.sub.2O.sub.5, TiO.sub.2, Y.sub.2O.sub.3, Si.sub.3N.sub.4,
SrTiO.sub.3 and WO.sub.3.
[0111] In a twenty-first aspect, the disclosure provides the glass
article of any of the fifteenth through twentieth aspects, wherein
the low refractive index material is selected from the group
consisting of SiO.sub.2, MgF.sub.2, YF.sub.3, YbF.sub.3, and
Al.sub.2O.sub.3.
[0112] In a twenty-second aspect, the disclosure provides the glass
article of any of the fifteenth through twenty-first aspects,
wherein the glass article has a water contact angle of at least
75.degree. after 6,000 abrasion cycles.
[0113] In a twenty-third aspect, the disclosure provides the glass
article of any of the fifteenth through twenty-second aspects,
wherein the glass article has a water contact angle of at least
105.degree. after 6,000 abrasion cycles.
[0114] In a twenty-fourth aspect, the disclosure provides the glass
article of any of the fifteenth through twenty-third aspects,
wherein the glass article has a water contact angle of greater than
90.degree. after 10,600 abrasion cycles.
[0115] In a twenty-fifth aspect, the disclosure provides the glass
article of any of the fifteenth through twenty-fourth aspects,
wherein after 8,000 abrasion cycles, scratches on a surface of the
glass article are less than 2 mm in length.
[0116] In a twenty-sixth aspect, the disclosure provides the glass
article of any of the fifteenth through twenty-fifth aspects,
wherein a % Reflectance of the glass article after at least 8,000
abrasion/wiping cycles is substantially the same as the %
Reflectance of an unabraded/unwiped glass article.
[0117] In a twenty-seventh aspect, the disclosure provides the
glass article of any of the fifteenth through twenty-sixth aspects,
wherein a % Transmission of the glass article after at least 8,000
abrasion/wiping cycles is substantially the same as the %
Transmission of an unabraded/unwiped glass article.
[0118] In a twenty-eighth aspect, the disclosure provides a coating
apparatus for coating a substrate with an optical coating and an
ETC coating. The coating apparatus comprises: a vacuum chamber; a
magnetic rotatable dome positioned in the vacuum chamber; at least
one e-beam source positioned in the vacuum chamber; at least one
thermal evaporation source positioned in the vacuum chamber; and a
shadow mask adjustably positioned on a support within the vacuum
chamber.
[0119] In a twenty-ninth aspect, the disclosure provides the
coating apparatus of the twenty-eighth aspect, wherein the coating
apparatus further comprises a plasma source positioned in the
vacuum chamber.
[0120] In a thirtieth aspect, the disclosure provides the coating
apparatus of any of the twenty-eighth through twenty-ninth aspects,
wherein the rotatable magnetic dome comprises: an opening at a top
center of the magnetic rotatable dome; a transparent glass plate
covering the opening of the magnetic rotatable dome; and a quartz
monitor positioned in an opening in the transparent glass plate for
monitoring a deposition rate of coating material deposited in the
vacuum chamber.
[0121] In a thirty-first aspect, the disclosure provides the
coating apparatus the thirtieth aspect, wherein the coating
apparatus further comprises an optical fiber positioned above the
transparent glass plate, wherein the optical fiber collects light
reflected from the transparent glass plate as the transparent glass
plate is coated to determine a change in reflectance of the
transparent glass plate and thereby a thickness of coatings applied
to the transparent glass plate.
[0122] In a thirty-second aspect, the disclosure provides the
coating apparatus of any of the twenty-eighth through thirty-first
aspects, wherein the magnetic rotatable dome is attached to a
vacuum shielded rotation shaft to facilitate rotation of the
magnetic rotatable dome.
[0123] In a thirty-third aspect, the disclosure provides the
coating apparatus of any of the twenty-eighth through thirty-second
aspects, wherein the coating apparatus further comprises at least
one magnetic substrate carrier magnetically attached to the
magnetic rotatable dome.
[0124] In a thirty-fourth aspect, the disclosure provides a process
for making glass articles having an optical coating in the glass
articles and an easy-to-clean, ETC, coating on top of the optical
coating, the process comprising: providing a coating apparatus
having at chamber for the deposition of an optical coating and ETC
coating; providing a rotatable dome within said chamber for
magnetically positioning a substrate carrier having an glass
substrate thereon that is to be coated, said dome being concave and
having a an opening at the top for the placement of quartz and
optical fiber measuring elements; providing within said chamber
source materials for the optical coating and source materials for
the ETC coating, wherein when a plurality of source materials are
required for making the optical coating, each of the plurality of
materials is provided in a separate source container; providing a
glass substrate, loading the glass substrate on the substrate
carrier and magnetically attaching the substrate carrier having the
glass substrate thereon to the dome; evacuating the chamber to a
pressure of 10.sup.-4 Torr or less; rotating the dome and
depositing an optical coating on the glass substrate; easing the
deposition of the optical coating following the deposition of the
optical coating, rotating the dome and depositing the ETC coating
on top of the optical coating; easing the deposition of the ETC
coating; cring the ETC coating; and removing the substrate having
an optical coating and an ETC coating from the chamber to obtain a
glass substrate having an optical coating deposited on the
substrate and an ETC coating deposited on the optical coating.
[0125] In a thirty-fifth aspect, the disclosure provides the method
of the thirty-fifth aspect wherein the optical coating is a
multilayer coating consisting of alternating layers of a high
refractive index metal oxide and a low refractive index metal
oxide, and each high/low index pair of layers is deemed to be a
coating period. The number of periods is in the range of 2-1000.
The multilayer coating has a thickness in the range of 100 nm to
2000 nm. The ETC materials is an alkyl perfluorocarbon silane of
formula (R.sub.F).sub.xSiX.sub.4-x, where R.sub.f is a linear
C.sub.6-C.sub.30 alkyl perfluorocarbon, X.dbd.Cl or --OCH.sub.3--
and x=2 or 3. The alkyl perfluorocarbon have a carbon chain length
in the range of 3 nm to 50 nm. Perfluorinated ethers attached to
the above SiX.sub.4-x moiety can also be used as ETC coating
materials.
[0126] In a thirty-sixth aspect, the disclosure provides the method
of the thirty-third through thirty-fifth aspects the optical
coating and the ETC coating are deposited in a chamber, and the
optical coating is densified during deposition using an ion beam or
a plasma. In a further embodiment, when the optical coating is an
oxide coating, oxygen or oxygen ions are present in the chamber to
insure that the stoichiometry of the metal oxide(s) being coated is
maintained.
[0127] In a thirty-seventh aspect the disclosure is also directed
to an apparatus for making a "shadowless" or "shadow free" glass
article having an optical coating and an ETC coating thereon, the
apparatus comprising a vacuum chamber having therein a source of
the optical coating materials and a source of the ETC coating
material, a rotatable dome having a plurality of substrate carriers
for holding substrates, the substrate carried being magnetically
attached to the rotatable dome.
[0128] In a thirty-eighth aspect, the disclosure provides a glass
article having an optical coating on the surface of the a glass
substrate and easy-to-clean coating on top of the optical coating,
said glass article being shadow free across the optically coated
surface of the glass; wherein the optical coating is a plurality of
periods consisting of a layer of a high refractive index material
H, n=1.7-3.0, and a low refractive index material L, n=1.3-1.61,
the H layer being the first layer of each period and the L layer
being the second layer of each period; and when the last L layer of
the optical coating is not SiO.sub.2, a SiO.sub.2 capping layer
having a thickness in the range of 20-200 nm is applied on top of
the plurality of periods. When the last period of the optical
coating is SiO.sub.2 and additional SiO layer having a thickness in
the range of 20-200 nm can optionally be deposited as a capping
layer. In one embodiment the number of optical coating periods is
in the range of 2-1000. In another embodiment the thickness of the
optical coating thickness in the range of 100 nm to 2000 nm. The
number of optical coating periods is in the range 2-20, and the
thickness of each of the high refractive index materials and the
low refractive index materials is in the range of 5-200 nm. In
another embodiment the number of optical coating periods is in the
range 2-20, and the thickness of each of the high refractive index
material and the low refractive index materials is in the range of
5-100 nm. The high index coating material is selected from the
group consisting of ZrO.sub.2, HfO.sub.2, Ta.sub.2O.sub.5,
Nb.sub.2O.sub.5, TiO.sub.2, Y.sub.2O.sub.3, Si.sub.3N.sub.4,
SrTiO.sub.3 and WO.sub.3. The low index coating material is
selected from the group consisting of SiO.sub.2, MgF.sub.2,
YF.sub.3 and YbF.sub.3. In an embodiment Al.sub.2O.sub.3,
n--1.5-1.7. is used in place of the low refractive index material
and a capping layer of SiO.sub.2 is applied as the final layer.
[0129] In a thirty-ninth aspect, the disclosure provides the method
of any of the first through twelfth aspects and the glass artricle
of any of the fifteenth through twenty-seventh aspects, wherein a
variation in a thickness of the optical coating across a coated
surface of the glass substrate or the glass article is less than or
equal to 3%.
[0130] In a fortieth aspect, the disclosure provides the method of
any of the first through twelfth aspects and the glass artricle of
any of the fifteenth through twenty-seventh aspects, wherein a
variation in a thickness of the optical coating across a coated
surface of the glass substrate or the glass article is less than or
equal to 2%.
[0131] In a forty-first aspect, the disclosure provides the method
of any of the first through twelfth aspects and the glass artricle
of any of the fifteenth through twenty-seventh aspects, wherein a
variation in a thickness of the optical coating across a coated
surface of the glass substrate or the glass article is less than or
equal to 1%.
[0132] It will be apparent to those skilled in the art that various
modifications and variations can be made to the embodiments
described herein without departing from the spirit and scope of the
claimed subject matter. Thus it is intended that the specification
cover the modifications and variations of the various embodiments
described herein provided such modification and variations come
within the scope of the appended claims and their equivalents.
* * * * *