U.S. patent application number 15/620715 was filed with the patent office on 2017-12-14 for protected item including a protective coating.
This patent application is currently assigned to VIAVI SOLUTIONS INC.. The applicant listed for this patent is VIAVI SOLUTIONS INC.. Invention is credited to Markus BILGER, Karen HENDRIX, Georg OCKENFUSS, James SWITZER.
Application Number | 20170357033 15/620715 |
Document ID | / |
Family ID | 60573816 |
Filed Date | 2017-12-14 |
United States Patent
Application |
20170357033 |
Kind Code |
A1 |
OCKENFUSS; Georg ; et
al. |
December 14, 2017 |
PROTECTED ITEM INCLUDING A PROTECTIVE COATING
Abstract
There is disclosed a protected item including an item that needs
protection and a protective coating having a hardness of at least
about 8 on the Mohs scale. The protected item includes a light
transmission in part or all of the visible wavelength of at least
about 60% and a light reflection in the visible wavelength of about
4% or less.
Inventors: |
OCKENFUSS; Georg; (Santa
Rosa, CA) ; BILGER; Markus; (Santa Rosa, CA) ;
HENDRIX; Karen; (Santa Rosa, CA) ; SWITZER;
James; (Santa Rosa, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VIAVI SOLUTIONS INC. |
Milpitas |
CA |
US |
|
|
Assignee: |
VIAVI SOLUTIONS INC.
Milpitas
CA
|
Family ID: |
60573816 |
Appl. No.: |
15/620715 |
Filed: |
June 12, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62349406 |
Jun 13, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 14/3457 20130101;
G01N 2021/3568 20130101; G02B 5/1809 20130101; G02B 1/115 20130101;
G02B 1/14 20150115; G02B 5/285 20130101; G02B 5/208 20130101; C23C
14/0635 20130101; G02B 5/20 20130101; G02B 5/3066 20130101; C23C
14/3464 20130101; G01N 21/17 20130101 |
International
Class: |
G02B 1/14 20060101
G02B001/14; C23C 14/06 20060101 C23C014/06; C23C 14/34 20060101
C23C014/34; G02B 5/20 20060101 G02B005/20; G02B 1/115 20060101
G02B001/115 |
Claims
1. A protected item comprising: an item that needs protection; and
a protective coating having a hardness of at least about 8 on the
Mohs scale, wherein the protected item includes a light
transmission in part or all of a visible wavelength of at least
about 60% and a light reflection in the visible wavelength of about
4% or less.
2. The protected item of claim 1, wherein the item that needs
protection includes a substrate and an optical filter.
3. The protected item of claim 2, wherein the substrate comprises
glass, silicon, polymer, or wafers.
4. The protected item of claim 3, wherein the wafers comprise
sapphire windows, a photodiode, a photodiode array, complementary
metal-oxide semiconductor sensors, and charge-coupled device
sensors.
5. The protected item of claim 2, wherein the optical filter
exhibits at least one of an anti-reflection property, an infrared
blocking property, and a bandpass filter property.
6. The protected item of claim 2, wherein the optical filter
includes at least one layer of at least one of Si, SiO.sub.2,
Si.sub.3N.sub.4, Al.sub.2O.sub.3, ZrO.sub.2, Y.sub.2O.sub.3,
Ta.sub.2O.sub.5, Nb.sub.2O.sub.5, NbTa.sub.2O.sub.5, NbTiO.sub.x,
SiC, and TiO.sub.2, wherein x is an integer from 1-6.
7. The protected item of claim 2, wherein the optical filter
exhibits an anti-reflection property and includes alternating
layers of SiO.sub.2 and NbTa.sub.2O.sub.5.
8. The protected item of claim 2, wherein the optical filter
exhibits an anti-reflection property and includes alternating
layers of Si.sub.3N.sub.4 and SiO.sub.2.
9. The protected item of claim 2, wherein the optical filter
exhibits an anti-reflection property and includes alternating
layers of NbTiO.sub.x and SiO.sub.2, wherein x is an integer from
1-6.
10. The protected item of claim 2, wherein the optical filter
exhibits an infrared blocking property and includes alternating
layers of NbTa.sub.2O.sub.5 and SiO.sub.2.
11. The protected item of claim 2, wherein the optical filter
exhibits a bandpass filter property and includes alternating layers
of Ta.sub.2O.sub.5 and SiO.sub.2.
12. The protected item of claim 1, wherein the protective coating
comprises at least one of silicon carbide, titanium carbide, boron,
boron nitride, rhenium diboride, stishovite, titanium diboride,
diamond, diamond-like carbon, and carbonado.
13. The protected item of claim 1, wherein the protective coating
comprises silicon carbide.
14. The protected item of claim 1, wherein the protective coating
includes a thickness of from about 3 nanometers to about 20
nanometers.
15. The protected item of claim 1, wherein the protective coating
is annealed to the item that needs protection.
16. A method for making a protected item comprising: providing an
item that needs protection; and depositing a protective coating
having a hardness of at least about 8 on the Mohs scale onto the
item that needs protection to form a protected item; wherein the
protected item includes a light transmission in part or all of a
visible wavelength of at least about 60% and a light reflection in
the visible wavelength of about 4% or less.
17. The method of claim 16, further comprising providing a
substrate; and depositing an optical filter onto the substrate to
form an item that needs protection.
18. The method of claim 16, wherein the protective coating is
deposited at a thickness of from about 3 nanometers to about 20
nanometers.
19. The method of claim 16, further comprising annealing the
deposited protective coating to the item that needs protection.
20. The method of claim 16, wherein the step of depositing a
protective coating is performed using a sputtering deposition
technique and includes the addition of hydrogen.
Description
FIELD OF THE INVENTION
[0001] The present disclosure generally relates to a protective
coating. The protective coating can be applied to any surface,
including an optical filter.
BACKGROUND OF THE INVENTION
[0002] Today, most of the displays for portable electronic devices
like smartphones, digital cameras, wearable devices, e.g., watches,
fitness tracker devices, etc., do not include an anti-reflective
coating. However, because of the optical interference created by
the displays of these products, the displays without an
anti-reflection coating can be difficult to see or read, especially
on a sunny day. Anti-reflective coatings are not as durable as a
substrate (e.g., "gorilla" glass or sapphire windows) on which it
is coated. Therefore, the displays with anti-reflective coatings
for the visible spectral range are cosmetically degraded by even
small blemishes.
SUMMARY OF INVENTION
[0003] In an aspect, there is disclosed a protected item comprising
an item that needs protection and a protective coating having a
hardness of at least about 8 on the Mohs scale, wherein the
protected item includes a light transmission in the visible
wavelength of at least about 60% and a light reflection in the
visible wavelength of about 4% or less.
[0004] In a further aspect, there is disclosed a method for making
a protected item comprising providing an item that needs
protection; and depositing a protective coating having a hardness
of at least about 8 on the Mohs scale onto the item that needs
protection to form a protected item, wherein the protected item
includes a light transmission in the visible wavelength of at least
about 60% and a light reflection in the visible wavelength of about
4% or less.
[0005] Additional features and advantages of various aspects of the
invention will be set forth, in part, in the description that
follows, and will, in part, be apparent from the description, or
may be learned by the practice of various aspects. The objectives
and other advantages of various aspects will be realized and
attained by means of the elements and combinations particularly
pointed out in the description herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The present invention in its several aspects can be more
fully understood from the detailed description and the accompanying
drawings, wherein:
[0007] FIG. 1 is a cross sectional view of a protected item
including a protective coating and an item that needs protection
according to an example of the present disclosure;
[0008] FIG. 2A is a cross sectional view of an item that needs
protection according to an example of the present disclosure;
[0009] FIG. 2B is a graph illustrating reflection of light at
various angles of incidence for a substrate of an item that needs
protection;
[0010] FIG. 2C is a graph illustrating reflection of light at
various angles of incidence for an item that needs protection;
[0011] FIG. 3A is a cross sectional view of a protected item
according to another example of the present disclosure;
[0012] FIG. 3B is a graph illustrating the reflection of light at
various angles of incidence for the protected item of FIG. 3A
according to an example of the present disclosure;
[0013] FIG. 3C is a graph illustrating the transmission of light at
various angles of incidence for the protected item of FIG. 3A
according to an example of the present disclosure;
[0014] FIG. 4A is a cross sectional view of a protected item
according to another example of the present disclosure;
[0015] FIG. 4B is a graph illustrating the reflection and the
transmission of light for the protected item of FIG. 4A according
to an example of the present disclosure;
[0016] FIG. 5A is a cross sectional view of a protected item
according to another example of the present disclosure;
[0017] FIG. 5B is a graph illustrating the reflection and the
transmission of light for the protected item of FIG. 5A according
to an example of the present disclosure;
[0018] FIG. 6A is a cross sectional view of a protected item
according to another example of the present disclosure;
[0019] FIG. 6B is a graph illustrating the reflection and the
transmission of light for the protected item of FIG. 6A according
to an example of the present disclosure;
[0020] FIG. 6C is a graph illustrate the reflection and the
transmission of light for an item that needs protection;
[0021] FIG. 7A is a cross sectional view of a protected item
according to another example of the present disclosure;
[0022] FIG. 7B is a graph illustrating the transmission of light
for the protected item of FIG. 7A according to an example of the
present disclosure;
[0023] FIG. 8 illustrates relative hardness of different protective
coatings according to an example of the present disclosure;
[0024] FIG. 9 is a graph illustrating the effects of varying
hydrogen flow on the transmission of light after deposition of a
protective coating; and
[0025] FIG. 10 is a graph illustrating the effects of annealing of
a protective coating on the transmission of light.
[0026] Throughout this specification and figures like reference
numbers identify like elements.
DETAILED DESCRIPTION OF THE INVENTION
[0027] For simplicity and illustrative purposes, the present
disclosure is described by referring mainly to examples thereof. In
the following description, numerous specific details are set forth
in order to provide a thorough understanding of the present
disclosure. It will be readily apparent however, that the present
disclosure may be practiced without limitation to these specific
details. In other instances, some methods and structures readily
understood by one of ordinary skill in the art have not been
described in detail so as not to unnecessarily obscure the present
disclosure.
[0028] For purposes of the present disclosure, the words "bandpass
filter properties" or "bandpass properties" can be defined as an
optical filter that can pass wavelengths or frequencies within a
certain range and can reject or attenuate wavelengths or
frequencies outside that certain range. Furthermore, "infrared
blocking properties" can be defined as an optical filter that is
capable of reflecting or blocking at least near-infrared
wavelengths while passing visible light. "Antireflection
properties" can be defined as an optical filter that is capable of
at least reducing reflection and/or stray light.
[0029] Furthermore, numeric values and ranges herein, unless
otherwise stated, are intended to have associated with them a
tolerance and to account for variances of design and manufacturing.
Thus, a number is intended to include values "about" that number.
For example, a value X is also intended to be understood as "about
X". Likewise, a range of Y-Z is also intended to be understood as a
range of from "about Y-about Z". Unless otherwise stated,
significant digits disclosed for a number are not intended to make
the number an exact limiting value. Variance and tolerance is
inherent in mechanical design and the numbers disclosed herein are
intended to be construed to allow for such factors (in non-limiting
e.g., .+-.10 percent of a given value). Example numbers disclosed
within ranges are intended also to disclose sub-ranges within a
broader range which have an example number as an endpoint. A
disclosure of any two example numbers which are within a broader
range is also intended herein to disclose a range between such
example numbers. Likewise, the claims are to be broadly construed
in their recitations of numbers and ranges.
[0030] Aspects of the present disclosure relate to a protected item
10 including an item 20 that needs protection; and a protective
coating 30, as shown in FIG. 1. The protective coating 30 can be
used on any item 20 that needs protection to reduce or
substantially inhibit the likelihood of the item scratching or
breaking. Additionally, the protective coating 30 would not change
the effects, i.e., the optical property or optical properties, of
the item 20 that needs protection, for example, reflection,
transmission, etc. Some examples of items 20 that need protection
include, but are not limited to, smart phones, tablets, touch
screen computers, camera lenses, eyeglasses, touch screens or
panels, and finger print readers.
[0031] As shown in FIG. 2A, the item 20 that needs protection can
be, for example, a substrate 40 with an optical filter 50 disposed
thereon. The substrate 40 can include, but is not limited to, glass
(e.g., gorilla glass, borosilicate glass), silicon, polymer, or
wafers such as sapphire windows, photodiode, photodiode array,
complementary metal-oxide semiconductor (CMOS) sensors, and
charge-coupled device (CCD) sensors.
[0032] The substrate 40 can reflect light at various angles of
incidence (AOI). For example, as shown in FIG. 2B, a sapphire
substrate 40 can reflect light from about 7.5% to about 9% at
various angles of incidence (AOI at 0.degree.,
15.degree.,30.degree., and 45.degree.). The inclusion of an optical
filter 50 on the substrate 40, as shown in FIG. 2A, can change the
ability of the substrate 40 to reflect and/or transmit light. For
example, an anti-reflection coating, as the optical filter 50, on
the sapphire substrate 40 from FIG. 2B should reduce the reflection
of light at various angles of incidence. As shown in FIG. 2C, an
optical filter 50, such as an anti-reflection coating ending with a
silicon dioxide layer, can greatly reduce the reflection of light
in the visible wavelength at various angles of incidence (AOI at
0.degree., 15.degree., 30.degree., 45.degree., and 60.degree.). In
particular, an item 20 that needs protection can have a light
reflection in the visible wavelength of about 4% or less. In an
aspect, the inclusion of a protective coating 30 would not, or a de
minimis manner, change the effects wrought by the optical filter
50, i.e., the anti-reflection coating of the optical filter 50
would still reduce the reflection of light.
[0033] The substrate 40 can include a thickness of from about 0.1
mm or less to about 20 mm or more, for example, from 0.1 mm to 10
mm, from 0.2 mm to 7.5 mm, from 0.3 mm to 7 mm, from 0.4 mm to 6.5
mm, from 0.5 mm to 6 mm, from 0.6 mm to 5 mm, from 0.7 mm to 4 mm,
from 0.8 mm to 3 mm, from 0.9 mm to 2 mm, and from 1 mm to 1.5
mm.
[0034] As shown in FIG. 2A, the optical filter 50 can include at
least one layer (50-1) including up to n layers (n is an
integer>1) (50-n), for example, two layers, three layers, four
layers, etc. In an aspect, the optical filter 50 can include an
even number of layers or can include an odd number of layers. The
number of layers present in the optical filter 50 can be determined
by various factors, such as the compound included in each
individual layer, and/or the optical property to be exhibited by
the optical filter 50, and/or the thickness of each layer in the
optical filter 50. The optical filter 50 can exhibit any optical
properties such as absorptive, interference, monochromatic,
dichroic, ultraviolet blocking, infrared blocking, anti-reflection,
bandpass, neutral density, longpass, shortpass, guided-mode
resonance, metal mesh, polarizer, arc welding, low-reflection,
optically-variable, color-shifting, optical interference,
transparent conductive, high-reflection, etc. Compounds that can be
used in the at least one layer of the optical filter 50 include,
but are not limited to, one or more of Si, silicon dioxide
(SiO.sub.2), silicon nitride (Si.sub.3N.sub.4), aluminum oxide
(Al.sub.2O.sub.3), ZrO.sub.2, Y.sub.2O.sub.3, tantalum pentoxide
(Ta.sub.2O.sub.5), niobium pentoxide (Nb.sub.2O.sub.5),
NbTa.sub.2O.sub.5, NbTiO.sub.x, wherein x is an integer ranging
from 1 to 6, SiC, and titanium dioxide (TiO.sub.2). Additionally,
the thickness of each layer of the optical filter 50 can each
independently be from 1 nm or less to 2000 nm or more, such as from
3 nm to 300 nm, from 10 nm to 180 nm, from 20 nm to 160 nm, from 30
nm to 140 nm, from 40 nm to 120 nm, from 50 nm to 100 nm, from 60
nm to 90 nm, and from 70 nm to 80 nm.
[0035] In an aspect, the optical filter 50 can include alternating
layers of two different compounds, for example, alternating layers
of SiO.sub.2 and NbTa.sub.2O.sub.5, wherein the number of
alternating layers is n (n is an integer>1), for example from
about 2 to about 66, for example from about 2 to about 48, and as a
further example from about 2 to about 35. An optical filter 50
exhibiting anti-reflection properties can include, for example, 35
alternating layers of SiO.sub.2 and NbTa.sub.2O.sub.5 (FIG. 3A);
four (4) alternating layers of Si.sub.3N.sub.4 and SiO.sub.2 (FIG.
4A); or six (6) alternating layers of NbTiO.sub.x and SiO.sub.2,
(FIG. 5A). An exemplary optical filter 50 exhibiting an infrared
blocking property can include, for example, sixty-six (66)
alternating layers of NbTa.sub.2O.sub.5 and SiO.sub.2, as shown in
FIG. 6A. An exemplary optical filter 50 exhibiting a bandpass
filter property can include, for example, 48 alternating layers of
Ta.sub.2O.sub.5 and SiO.sub.2, as shown in FIG. 7A. The optical
filter 50 can exhibit at least one of an anti-reflection property,
an infrared blocking property, and a bandpass filter property.
[0036] A protective coating 30 can be applied to the item 20 that
needs protection to form the protected item 10, as shown in FIG. 1.
The protective coating 30 can have a hardness of at least about 8
on the Mohs scale, and can be present in a thickness ranging from
about 1 to about 2000 nm. An example of a protective coating 30 can
be silicon carbide (SiC) because it is a very durable material.
Alternatively, or in addition to the silicon carbide, another
material can be included in the protective coating 30, including
but not limited to titanium carbide, boron, boron nitride, rhenium
diboride, stishovite, titanium diboride, diamond, diamond-like
carbon (DLC) and carbonado. The other material should not
negatively impact the attributes of the protective coating 30 and
should also not negatively impact the optical properties associated
with the optical filter 50 of the item 20 that needs
protection.
[0037] Moreover, the protective coating 30 can have a hardness of
at least about 8 on the Mohs scale, for example from about 9 to
about 9.5. FIG. 8 illustrates the relative hardness of different
materials, such as sapphire, SiC, silicon dioxide, silicon, and
fused silica, in which a lower indentation depth is understood to
reflect a higher relative hardness and thus a higher resistance to
scratches. According to FIG. 8, at a load of 77 .mu.N, SiC has an
indentation depth of approximately 3.5 nm, and sapphire has an
indentation depth of approximately 2.5 nm. Silicon dioxide,
silicon, and fused silica all have an indentation depth of over 8
nm. At a load of 91 .mu.N, SiC and sapphire have an indentation
depth of approximately 3.8 nm. Silicon dioxide, silicon, and fused
silica all have an indentation depth of over 8 nm. Furthermore, at
a load of 105 .mu.N, SiC has an indentation depth of approximately
4.1 nm, and sapphire has an indentation depth of approximately 4.7
nm. Silicon dioxide, silicon, and fused silica all have an
indentation depth of over 10 nm. Accordingly, at higher loads, SiC
has a higher resistance to scratches than sapphire, silicon
dioxide, silicon, and fused silica. Sapphire has a hardness of
about 9, fused silica has a hardness of about 5.3 to about 6.5, and
silicon has a hardness of about 7 on the Mohs scale. One of
ordinary skill in the art would know that the Mohs scale is not
linear, but is instead exponential.
[0038] The protective coating 30 can include a thickness of from
about 1 nm to about 2000 nm, for example from about 2 nm to 1000
nm, such as from about 3 nm to about 20 nm or from about 5 nm to
about 2.0 nm. This range of thickness can provide ideal light
transmission, light reflection, and provide ideal hardness/scratch
resistance. In particular, a protective coating 30 can be absorbing
in the visible range wavelength, so a reduced thickness can be
applied to avoid too much light loss.
[0039] In an aspect, the protected item 10 can have a light
transmission of at least about 60% in part or all of the visible
wavelength and a light reflection of about 4% or less in the
visible wavelength. The light transmission in part or all of the
visible wavelength can be at least about 65%, 70%, 75%, 80%, 85%,
90%, 95%, or even about 100%. Additionally, the light reflection in
the visible wavelength can be about 3.5%, 3%, 2.5%, 2%, 1.5% and
below, such as 1.4%, 1.3%, 1.2%, 1.1%, 0.9%, 0.8%, 0.7%, 0.6%,
0.5%, 0.4%, 0.3%, 0.2%, or even about 0.1% or lower.
[0040] The method of making a protected item 10 can include
depositing the protective coating 30, and in particular, a method
of depositing the protective coating 30 including SiC, onto an item
20 that needs protection. The deposition of the protective coating
30 can play a part in the performance of the protected item 10. The
method of making a protected item 10 can include providing an item
20 that needs protection and depositing a protective coating 30
onto the item 20. The method can further include a method of making
the item 20 that needs protection including providing a substrate
40 and depositing an optical filter 50 onto the substrate 40. The
deposition of the optical filter 50 onto the substrate can include
known deposition techniques, such as magnetron sputtering, direct
current sputtering, pulsed sputtering, alternate current
sputtering, radio frequency sputtering, ion beam sputtering, and
assisted ion beam sputtering; thermal evaporation, electron beam
evaporation, ion assisted evaporation, chemical vapor deposition,
and plasma-enhanced chemical vapor deposition. The protective
coating 30 can be deposited on the optical filter 50 using similar
deposition techniques, such as sputtering deposition techniques,
and can include the addition of hydrogen. In this manner, the
protective coating 30 can be applied in a reduced thickness. The
method can further include annealing the protective coating 30 to
the item 20 that needs to be protected to form the protected item
10. The protective coating 30 can be deposited onto the item 20
that needs protection, in particular, onto the optical filter 50 of
the item 20, using a dual cathode or a single cathode sputtering
process. The optical properties of the protective coating 30 can
depend on the hydrogen content and, therefore, on the hydrogen flow
rate during the deposition step. Additionally, the optical
properties of the protective coating 30 can also be influenced by
other parameters, such as the flow rate of the inert gas, the PAS
(plasma activation source) power level, the cathode power level,
and the deposition rate.
[0041] The process parameters and values can vary depending on the
coating process, chamber size, and many other factors. Generally,
the temperature of the deposition process can be from 10.degree. C.
or less to 150.degree. C. or more, such as from 15.degree. C. to
100.degree. C. or from 20.degree. C. to 90.degree. C. Furthermore,
the pressure can be from 1.times.10.sup.-6 mtorr to
1.times.10.sup.-2 mtorr, such as from 5.times.10.sup.-4 mtorr to
5.times.10.sup.-3 mtorr. Moreover, the hydrogen gas flow can be
from 10 SCCM or less to 200 SCCM or more, such as 20 SCCM, 40 SCCM,
60 SCCM, 80 SCCM, 100 SCCM, 120 SCCM, 140 SCCM, 160 SCCM, 180 SCCM,
and 200 SCCM. Furthermore, the inert gas, such as argon gas, flow
can be from 50 SCCM to 500 SCCM, for example, 150 SCCM or more,
such as 200 SCCM, 204 SCCM, 295 SCCM, and 390 SCCM.
[0042] The method of making the protected item 10 can further
include annealing the protective coating 30. In an aspect, if a
single cathode sputtering process is used, the protective coating
30 can be annealed. In another aspect, if a dual cathode sputtering
process is used, the protective coating 30 does not have to be
annealed. The annealing temperature can be at any temperature
greater than 90.degree. C. For example, the annealing can take
place at a temperature of 100.degree. C., 200.degree. C.,
250.degree. C., 240.degree. C., 300.degree. C., 350.degree. C.,
400.degree. C., or more. The annealing process can take anywhere
from 30 minutes to 24 hours. For example, the annealing process can
take from 40 minutes to 10 hours, from 45 minutes to 5 hours, from
50 minutes to 2 hours, such as an hour. In one example, the
annealing process takes place at a temperature of about 280.degree.
C. for about 1 hour. In another example, the annealing process
takes place at a temperature of about 400.degree. C. for about 1
hour.
EXAMPLES
[0043] To determine the effects of using a protective coating 30 on
an optical filter 50, such as an anti-reflection coating, an
infrared blocker, and a bandpass filter, the following protected
items 10 were made.
[0044] FIG. 3A illustrates a protected item 10 including a sapphire
substrate 40 with an optical filter 50. The optical filter 50
included 35 alternating layers of silicon dioxide and
NbTa.sub.2O.sub.5. A protective coating 30 of silicon carbide was
deposited onto the optical filter 50 at a thickness of 6 nm. The
reflection of light in the visible wavelength was 4% or less (FIG.
3B) and the transmission of light in the visible wavelength was at
least about 60% (FIG. 3C). As can be seen from a comparison of
FIGS. 2C and 3B, the inclusion of a protective coating 30 of SiC
does not substantially alter the effects of the optical filter 50,
an anti-reflection coating.
[0045] FIG. 4A illustrates a protected item 10 including a sapphire
substrate 40 with an optical filter 50. The optical filter 50
included 4 alternating layers of Si.sub.3N.sub.4 and silicon
dioxide. A protective coating 30 of silicon carbide was deposited
onto the optical filter 50 at a thickness of 6 nm. The reflection
of light in the visible wavelength was 4% or less and the
transmission of light in the visible wavelength was at least about
60% (FIG. 4B).
[0046] FIG. 5A illustrates a protected item 10 including a sapphire
substrate 40 with an optical filter 50. The optical filter 50
included 6 alternating layers of NbTiO.sub.x and silicon dioxide. A
protective coating 30 of silicon carbide was deposited onto the
optical filter 50 at a thickness of 6 nm. The reflection of light
in the visible wavelength was 4% or less and the transmission of
light in the visible wavelength was at least about 60% (FIG.
5B).
[0047] FIG. 6A illustrates a protected item 10 including a
borofloat substrate 40 with an optical filter 50. The optical
filter 50 included 66 alternating layers of NbTa.sub.2O.sub.5 and
silicon dioxide. A protective coating 30 of silicon carbide was
deposited onto the optical filter 50 at a thickness of 6 nm. The
reflection of light in the visible wavelength was 4% or less and
the transmission of light in the visible wavelength as at least
about 60% (FIG. 6B). In the infrared wavelength (700 nm to 1100
nm), there was a de minimis amount of light that was transmitted.
FIG. 6C illustrates the reflection of light and the transmission of
light for an item that needs protection 20, i.e., it does not
include a protective coating 30. As can be seen from a comparison
of FIGS. 6B and 6C, the inclusion of the protective coating 30
(FIG. 6B) does not, or in a de minimis manner, change the effects
wrought by the optical filter 50, e.g., an infrared blocker. The
infrared blocker property is exhibited by the protected item 10
while also yielding the scratch-resistance, for example, properties
of the protective coating 30.
[0048] FIG. 7A illustrates a protected item 10 including a
borofloat substrate 40 with an optical filter 50. The optical
filter 50 included 48 alternating layers of Ta.sub.2O.sub.5 and
silicon dioxide. A protective coating 30 of silicon carbide was
deposited onto the optical filter 50 at a thickness of 10 nm. The
transmission of light in certain areas of the visible wavelength
was at least about 60% (FIG. 7B).
[0049] To determine the effects of adding hydrogen during the
deposition of the protective coating 30 to the item 20 that needs
protection, the hydrogen flow was varied to provide a 2 .mu.m SiC
protective coating on a fused silica. The transmission of light was
measured for each varied flow rate over the visible and infrared
wavelengths. The data is shown in FIG. 9. As can be seen, an
increased flow rate of the hydrogen during deposition resulted in a
greater percentage of light that was transmitted thereby improving
the optical property of the protective coating 30.
[0050] To determine the effects of annealing of the protective
coating 30 after its deposition to the item 20 that needs
protection, the temperature was varied. During deposition the
hydrogen flow was 120 SCCM to provide a 2 .mu.m SiC protective
coating on a fused silica. FIG. 10 illustrates a control without
annealing (U07342 AD), an annealing temperature at 280.degree. C.
for 1 hour (U07342 2808), an annealing temperature at 400.degree.
C. for 1 hour (U07342 4008). The transmission of light was measured
for each over the visible and infrared wavelengths. The data is
shown in FIG. 10. As can be seen, annealing the protective coating
30 resulted in a greater percentage of light that was transmitted
thereby improving the optical property of the protective coating
30.
[0051] From the foregoing description, those skilled in the art can
appreciate that the present teachings can be implemented in a
variety of forms. Therefore, while these teachings have been
described in connection with particular aspects and examples
thereof, the true scope of the present teachings should not be so
limited. Various changes and modifications may be made without
departing from the scope of the teachings herein.
[0052] This scope disclosure is to be broadly construed. It is
intended that this disclosure disclose equivalents, means, systems
and methods to achieve the devices, activities and mechanical
actions disclosed herein. For each device, article, method, mean,
mechanical element or mechanism disclosed, it is intended that this
disclosure also encompass in its disclosure and teaches
equivalents, means, systems and methods for practicing the many
aspects, mechanisms and devices disclosed herein. Additionally,
this disclosure regards a coating and its many aspects, features
and elements. Such a device can be dynamic in its use an operation,
this disclosure is intended to encompass the equivalents, means,
systems and methods of the use of the device and/or article of
manufacture and its many aspects consistent with the description
and spirit of the operations and functions disclosed herein. The
claims of this application are likewise to be broadly
construed.
[0053] The description of the inventions herein in their many
aspects is merely an example and, thus, variations that do not
depart from the gist of the invention are intended to be within the
scope of the invention. Such variations are not to be regarded as a
departure from the spirit and scope of the invention.
* * * * *