U.S. patent application number 10/686689 was filed with the patent office on 2004-09-02 for systems and methods involving optical fibers having separate color layers.
Invention is credited to Kenkare, Nirupama, Moore, Robert C., Turnipseed, John M., Xiong, Shunhe.
Application Number | 20040170367 10/686689 |
Document ID | / |
Family ID | 32771512 |
Filed Date | 2004-09-02 |
United States Patent
Application |
20040170367 |
Kind Code |
A1 |
Kenkare, Nirupama ; et
al. |
September 2, 2004 |
Systems and methods involving optical fibers having separate color
layers
Abstract
An optical fiber including a layer of primary coating material
having a first modulus, a layer of color coating material having a
second modulus, a layer of secondary coating having a third
modulus, and wherein the first modulus, the second modulus, and the
third modulus are different values.
Inventors: |
Kenkare, Nirupama; (Tucker,
GA) ; Moore, Robert C.; (Roswell, GA) ;
Turnipseed, John M.; (Lilburn, GA) ; Xiong,
Shunhe; (Alpharetta, GA) |
Correspondence
Address: |
THOMAS, KAYDEN, HORSTEMEYER & RISLEY, LLP
100 GALLERIA PARKWAY, NW
STE 1750
ATLANTA
GA
30339-5948
US
|
Family ID: |
32771512 |
Appl. No.: |
10/686689 |
Filed: |
October 15, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10686689 |
Oct 15, 2003 |
|
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10376898 |
Feb 28, 2003 |
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Current U.S.
Class: |
385/128 ;
427/163.2 |
Current CPC
Class: |
Y10S 118/18 20130101;
C03C 25/18 20130101 |
Class at
Publication: |
385/128 ;
427/163.2 |
International
Class: |
G02B 006/22; B05D
005/06 |
Claims
What is claimed:
1. An applicator assembly for applying a primary coating material,
a secondary coating material and a color coating material to an
optical fiber, the assembly comprising: a pressurized source of the
primary coating material; a primary reservoir in fluid
communication with the pressurized source of the primary coating
material, the primary reservoir being configured for applying a
layer of the primary coating material to the optical fiber; a
primary die adjacent the primary reservoir, the primary die
including a primary land configured to size the layer of the
primary coating material; a pressurized source of the color coating
material; a color reservoir in fluid communication with the
pressurized source of the color coating material, the color
reservoir being configured for applying a layer of the color
coating material to the optical fiber; a color die adjacent the
color reservoir, the color die including a color land configured to
size the layer of the color coating material; a pressurized source
of the secondary coating material; a secondary reservoir in fluid
communication with the pressurized source of the secondary coating
material, the secondary reservoir being configured for applying a
layer of the secondary coating material to the optical fiber; and a
secondary die adjacent the secondary reservoir, the secondary die
including a secondary land configured to size the layer of the
secondary coating material; and wherein the primary reservoir,
color reservoir and the secondary reservoir are in fluid
communication.
2. The applicator assembly of claim 1, further comprising: an entry
die including an entry land, wherein the entry land, the primary
land, the color land, and the secondary land are substantially
axially aligned, and wherein the primary reservoir is disposed
between the entry land and the primary land, the color reservoir is
disposed between the primary land and the color land, and the
secondary reservoir is disposed between the color land and the
secondary land.
3. The applicator assembly of claim 1, further comprising: an entry
die including an entry land, wherein the entry land, the primary
land, the color land, and the secondary land are substantially
axially aligned, and wherein the primary reservoir is disposed
between the entry land and the primary land, the secondary
reservoir is disposed between the primary land and the secondary
land, and the color reservoir is disposed between the secondary
land and the color land.
4. The applicator assembly of claim 1, further comprising: an entry
die including an entry land, wherein the entry land, the primary
land, the color land, and the secondary land are substantially
axially aligned, and wherein the color reservoir is disposed
between the entry land and the color land, the primary reservoir is
disposed between the color land and the primary land, and the
secondary reservoir is disposed between the primary land and the
secondary land.
5. The applicator assembly of claim 1, further comprising: an entry
die including an entry land; a second primary reservoir for
applying a second layer of the primary coating material to the
optical fiber; a second primary die including a second primary land
configured to size the second layer of the primary coating
material; and wherein the entry land, the primary land, the second
primary land, the secondary land, and the color land are
substantially axially aligned.
6. The applicator assembly of claim 5, wherein the color reservoir
is disposed between the entry land and the color land, the primary
reservoir is disposed between the color land and the primary land,
the second primary reservoir is disposed between the primary land
and the second primary land, and the secondary reservoir is
disposed between the second primary land and the secondary
land.
7. The applicator assembly of claim 5, wherein the primary
reservoir is disposed between the entry land the primary land, the
second primary reservoir is disposed between the primary land and
the second primary land, the color reservoir is disposed between
the second primary land and the color land, and the secondary
reservoir is disposed between the color land and the secondary
land.
8. The applicator assembly of claim 5, wherein the primary
reservoir is disposed between the entry land and the primary land,
the second primary reservoir is disposed between the primary land
and the second primary land, the secondary reservoir is disposed
between the second primary land and the secondary land, and the
color reservoir is disposed between the secondary land and the
color land.
9. The applicator assembly of claim 1, wherein at least one of the
pressurized source of the primary coating material, the pressurized
source of the color coating material, and the pressurized source of
secondary coating material is a pump.
10. A method of forming an optical fiber, comprising the steps of:
drawing an optical fiber; applying a layer of primary coating
material to the optical fiber; applying a layer of color coating
material to the optical fiber; applying a layer of secondary
coating material to the optical fiber; and wherein the layer of
primary coating material, the layer of color coating material, and
the layer of secondary coating material are each applied prior to
the other layers being cured.
11. The method of claim 10, wherein the layer of color coating
material is disposed between and adjacent the optical fiber and the
layer of primary coating material.
12. The method of claim 10, wherein the layer of color coating is
disposed between and adjacent the layer of primary coating material
and the layer of secondary coating material.
13. The method of claim 12, wherein the step of applying a layer of
the primary coating material further comprises applying a first
layer of primary coating material adjacent the optical fiber and
applying a second layer of primary coating material between and
adjacent the first layer of primary coating material and the layer
of secondary coating material.
14. The method of claim 10, wherein the layer of primary coating
material is disposed between and adjacent the optical fiber and the
layer of secondary coating material and the layer of color coating
material is disposed adjacent the layer of secondary coating.
15. An optical fiber formed by the method of claim 10.
16. A method of forming an optical fiber, comprising the steps of:
(a) drawing an optical fiber; (b) applying a layer of primary
coating material to the optical fiber; (c) applying a layer of
color coating material to the layer of primary coating material;
and (d) applying a layer of secondary coating material to the layer
of color coating material.
17. The method of claim 16, wherein (c) further comprises applying
a second layer of primary coating between and adjacent the first
layer of primary coating material and the layer of secondary
coating material.
18. An optical fiber comprising: a layer of primary coating
material having a first modulus; a layer of color coating material
having a second modulus; a layer of secondary coating having a
third modulus; and wherein the first modulus, the second modulus,
and the third modulus are different values.
19. The optical fiber of claim 18, wherein the layer of color
coating material is adjacent the optical fiber and the layer of
primary coating material.
20. The optical fiber of claim 19, wherein the layer of color
coating material has a thickness of between 2 to 10 microns.
21. The optical fiber of claim 19, wherein the layer of color
coating material has a thickness of between 4 to 7 microns and the
layers of primary coating material and secondary coating material
each has a thickness from 15 to 40 microns.
22. The optical fiber of claim 18, wherein the layer of color
coating material is adjacent the layer of primary coating material
and the layer of secondary coating material.
23. The optical fiber of claim 22, wherein the layer of color
coating has a thickness of between 2 to 10 microns.
24. The optical fiber of claim 22, wherein the layer of color
coating material has a thickness of between 4 to 7 microns and the
layers of primary coating material and secondary coating material
each has a thickness from 15 to 40 microns.
25. The optical fiber of claim 18, wherein the layer of color
coating material is adjacent the layer of the secondary coating
material and further comprises an outermost layer of the optical
fiber.
26. The optical fiber of claim 22, wherein the layer of color
coating material has a thickness of between 2 to 10 microns.
27. The optical fiber of claim 22, wherein the layer of color
coating material has a thickness of between 4 to 7 microns and the
layers of primary coating material and secondary coating material
each has a thickness from 15 to 40 microns.
28. A system for forming an optical fiber, comprising: means for
drawing an optical fiber; means for applying a layer of primary
coating material to the optical fiber; means for applying a layer
of color coating material to the layer of the primary coating
material, but before the application of a layer of secondary
coating material; and means for applying the layer of secondary
coating material to the layer of the color coating material.
29. The system of claim 28, wherein the means for applying a layer
of primary coating material further comprises means for applying a
first layer adjacent the optical fiber and means for applying a
second layer adjacent the first layer.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of copending U.S.
utility application entitled, "MULTIPLE FEED APPLICATOR ASSEMBLY
FOR COATING OPTICAL FIBERS," having Ser. No. 10/376,898, filed Feb.
28, 2003, which is entirely incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention generally relates to coating optical
fibers. More particularly, the present invention relates to optical
fibers having separate color layers.
DESCRIPTION OF THE RELATED ART
[0003] Optical fiber production generally involves drawing a fiber,
which usually is composed of silica glass, and then applying
protective coating materials to the fiber. The primary layer of
coating material typically comprises a relatively soft, polymeric
material that protects the fiber from displacement, and subsequent
losses associated therewith. The primary layer helps to absorb
forces applied to the coated fiber and prevent their transmission
to the fiber core, as well as seal the surface of the fiber from
moisture to maintain high physical strength. Typically, a secondary
layer of coating material comprising a higher modulus polymeric
material is applied to the primary layer. The secondary layer
protects the soft primary layer, providing robustness and abrasion
resistance to the coated optical fiber.
[0004] In addition to protecting a fiber from displacement and
maintaining high strength of the fiber, the coatings also function
to prevent airborne particles from impinging upon and adhering to
the surface of the drawn fiber, which can weaken the fiber and
affect its transmission properties.
[0005] Optical fibers can be coated using a wet coating process
which typically involves drawing a fiber through a reservoir of
liquid polymer material and then curing the liquid polymer to
harden it by exposure to curing radiation, such as, ultra-violet
light. In a dual coating process, the coating materials are applied
in tandem or simultaneously (within the same applicator or die
assembly). The tandem arrangement applies a primary coating layer
which is then cured, and then a secondary coating material is
applied and cured. This process has been termed "wet-on-dry" in
trade literature. In a simultaneous dual coating arrangement, both
coating materials are applied to the fiber substrate after which
they are cured simultaneously with the exposure of suitable
radiation. In both cases, the primary coating material is typically
a low modulus polymeric material and the secondary coating material
is a relatively high modulus polymeric material
[0006] Optical fibers are often provided with coloration that
allows the individual fibers to be quickly and properly identified.
Existing methods include providing a color layer for the optical
fiber in a post-draw step. For example, for both the tandem and
simultaneous application arrangements, the color layer is provided
only after the outermost protective layer had been cured. This
method also constitutes a "wet-on-dry" coating process. Such a
colorization processes can require increased height on the draw
tower if this operation is performed during the draw process, or
else as an additional step after drawing the fiber has been
completed, both of which can increase manufacturing costs.
[0007] Present methods of colorization also include adding
colorants to the primary coating material, the secondary coating
material, or both. Addition of colorants to the primary and
secondary coating materials can affect the properties of the
materials, and therefore the performance of the optical fibers on
which they are used. As well, because the materials are colored
prior to application, it is not uncommon to have inventories of
unnecessarily colored materials remaining after drawing operations
are complete. These inventories often go to waste and contribute to
increased manufacturing costs.
SUMMARY
[0008] Briefly described, systems and methods involving optical
fibers having separate color layers provide an optical fiber
including a layer of primary coating material having a first
modulus, a layer of color coating material having a second modulus,
a layer of secondary material having a third modulus, and wherein
the first, the second, and the third moduli are different
values.
[0009] As well, other embodiments provide an apparatus and a method
for applying a color coating material, a primary coating material
and a secondary coating material to an optical fiber. A
representative embodiment of the applicator assembly includes: a
pressurized source of the primary coating material; a primary
reservoir in fluid communication with the pressurized source of the
primary coating material, the primary reservoir being configured
for applying a layer of the primary coating material to the optical
fiber; a primary die adjacent the primary reservoir, the primary
die including a primary land configured to size the layer of the
primary coating material; a pressurized source of the color coating
material; a color reservoir in fluid communication with the
pressurized source of the color coating material, the color
reservoir being configured for applying a layer of the color
coating material to the optical fiber; a color die adjacent the
color reservoir, the color die including a color land configured to
size the layer of the color coating material; a pressurized source
of the secondary coating material; a secondary reservoir in fluid
communication with the pressurized source of the secondary coating
material, the secondary reservoir being configured for applying a
layer of the secondary coating material to the optical fiber; a
secondary die adjacent the secondary reservoir, the secondary die
including a secondary land configured to size the layer of the
secondary coating material; and wherein the primary reservoir,
color reservoir and the secondary reservoir are in fluid
communication.
[0010] Another embodiment can also be viewed as a method for
forming an optical fiber. In this regard, a representative method
can be broadly summarized by the following steps: drawing an
optical fiber; applying a layer of primary coating material to the
optical fiber; applying a layer of color coating material to the
optical fiber; applying a layer of secondary coating material to
the optical fiber; wherein the layer of the primary coating
material, the layer of the color coating material, and the layer of
the secondary coating material are each applied prior to the other
layers being cured.
[0011] Other systems, methods, features and/or advantages will be
or may become apparent to one with skill in the art upon
examination of the following drawings and detailed description. It
is intended that all such additional systems, methods, features
and/or advantages be included within this description and be
protected by the accompanying claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The components in the drawings are not necessarily to scale.
Moreover, in the drawing, like reference numerals designate
corresponding parts throughout the several views.
[0013] FIG. 1 is a schematic diagram of a system for applying
coatings to optical fibers, including a preferred embodiment of the
applicator assembly.
[0014] FIGS. 2A-2C are perspective views of optical fibers having a
separate color layer, with portions of the various layers being
cut-away.
[0015] FIG. 3 is a cross-sectional view of a preferred embodiment
of the applicator assembly.
[0016] FIG. 4 is a cross-sectional view of a first coating die as
shown in FIG. 3.
[0017] FIG. 5 is a cross-sectional view of a second coating die as
shown in FIG. 3.
[0018] FIG. 6 is a cross-sectional view of a third coating die as
shown in FIG. 3.
[0019] FIG. 7 is a partial cross-sectional view of a portion of the
applicator assembly as shown in FIG. 3.
[0020] FIG. 8 is a cross-sectional view taken along line 8-8 of the
applicator assembly as shown in FIG. 3.
[0021] FIG. 9 is a cross-sectional view of the first die as shown
in FIG. 8.
[0022] FIG. 10 is a cross-sectional view of the second die as shown
in FIG. 8.
[0023] FIG. 11 is a cross-sectional view of the third die as shown
in FIG. 8.
[0024] FIG. 12 is a flow diagram showing a preferred embodiment of
a method of coating optical fibers.
DETAILED DESCRIPTION
[0025] Optical fibers, typically composed of silica glass, require
protective coatings that prevent damage to the fiber from moisture,
abrasion, stress, etc. These protective coatings typically include
a primary coating layer of a relatively soft, polymeric material
and a secondary coating layer of a polymeric material having a
higher modulus than the primary coating material. The protective
coatings are preferably applied soon after drawing the fiber.
[0026] Referring now in more detail to the drawings, FIG. 1 shows
an embodiment of a system 10, which is used to draw an optical
fiber 11 from a cylindrical preform 13 and then coat the optical
fiber 11 utilizing an embodiment of a multiple feed applicator
assembly 100. Typically, manufacture of optical fiber 11 begins by
drawing the glass preform 13 that is held in a furnace 12 at a
temperature of 2000.degree. C. or higher. Instruments 16, such as
cladding diameter and fiber tension gauges provide feedback to the
furnace temperature and draw capstan speed controllers (not shown).
The optical fiber 11 passes through several cooling stages, such as
an annealer 14 and a chiller 18, that control the axial temperature
profile of the optical fiber 11 within a desirable range. When the
optical fiber 11 has cooled enough, typically to less than
80.degree. C., two protective liquid coating materials and a color
coating material are applied with the multiple feed applicator
assembly 100. Note, although two protective coating layers are
typical, various numbers of protective coating layers can be
applied with the multiple feed applicator assembly 100. Next, the
coating layers are cured, typically in ultraviolet ovens 20, and
the coated optical fiber 30 is wound onto a takeup spool 24.
[0027] FIG. 2A illustrates an embodiment of a coated optical fiber
30A that includes a color coating layer 34 that is separate from
the primary coating layer 32 and the secondary coating layer 36. As
shown, the primary coating layer 32 is adjacent the optical fiber
11, the color coating layer 34 is adjacent the primary coating
layer 32, and the secondary coating layer 36 forms the outermost
protective layer. Preferably, the primary coating material is a
relatively soft polymeric material that protects the optical fiber
11 from displacement and losses associated therewith, while the
secondary coating material is a higher modulus polymeric material
that offers high strength and abrasion resistance. Typically, the
color coating material has a modulus (units of pressure) between
that of the primary and secondary coating materials. The modulus of
the color coating material can be chosen to optimize transmission
loss performance or subsequent required operations such as
stripping protective layers (such as ribbon matrix or buffer) from
the coated optical fiber 30.
[0028] FIGS. 2B and 2C illustrate alternative embodiments of the
coated optical fiber 30A as shown in FIG. 2A. In FIG. 2B, the color
coating layer 34 is adjacent to the optical fiber 11 and the
primary coating layer 32 is between the color coating layer 34 and
the outermost secondary coating layer 36. In FIG. 2C, the primary
coating layer 32 is adjacent the optical fiber 11, the secondary
coating layer 36 is adjacent the primary coating layer 32, and the
color coating layer 34 is the outermost layer. Preferably, the
material of each layer (primary 32, color 34 and secondary 36) is
selected with regard to the disposition of each layer within the
coated optical fiber 30A-C. Typically, each material will be of a
different modulus.
[0029] In the embodiments of the coated optical fibers 30A-C shown,
the primary and secondary coating layers 32, 36 are 15-40 microns
thick while the color coating layer 34 is 2-10 microns thick, but
preferably 4-7 microns thick.
[0030] FIG. 3 illustrates, in cross-section, an embodiment of the
multiple feed applicator assembly 100 for coating optical fibers as
shown in FIG. 1. For clarity, an optical fiber to be coated has not
been shown passing through the applicator assembly 100. However, as
shown in FIG. 7, an optical fiber 11 to be coated passes along the
centerline of the entry land 132, the first land 152, the second
land 166, and the third land 186. As assembled, the applicator
assembly 100 includes a die cap 120, an entry die 130, a first die
140, a second die 160, a third die 180, and a body portion 102. In
the preferred embodiment shown, the body portion 102 includes a
cavity 103 having tapered walls for receiving and supporting the
first die 140.
[0031] As shown in FIGS. 3 and 8, the body portion 102 includes a
first coating material source 104 (FIG. 8), a first coating port
108 (FIG. 8), a second coating material source 105, a second
coating port 110, a third coating material source 106 (FIG. 8), and
a third coating port 112 (FIG. 8). The first coating ports 108 of
the body portion 102 feed into an annular groove 146 formed in the
first die 140 adjacent to the body portion 102. The annular groove
146 is in fluid communication with first coating ports 108 formed
in the first die 140. Second coating ports 110 formed in the body
portion 102 are in fluid communication with the second coating
material source 105 and corresponding second coating ports 110
formed in the first die 140. The third coating ports 112 formed in
the body portion 102 are in fluid communication with the third
coating material source 106 and corresponding third coating ports
112 formed in the first die 140 and the second die 160, as best
seen in FIG. 8. Note, although multiple first coating material
sources 104, second coating material sources 105, and third coating
material sources 106 are shown, embodiments of the applicator
assembly 100 are envisioned wherein a single first coating material
source 104, a single second coating material source 105, and a
single third coating material source 106 are in fluid communication
with both the first coating ports 108, the second coating ports
110, and the third coating ports 112, respectively. The first,
second, and third coating material sources 104, 105, 106 can be
pressurized by one or more pumps (not shown), and like devices.
[0032] As shown in FIG. 4, the first die 140 includes a first
cavity 142 and second cavity 144. The first cavity 142 is arranged
and configured to receive an entry die 130 (FIG. 3). The entry die
130 includes an entry land 132 through which the optical fiber
passes. The entry land 132 helps to ensure coating material does
not flow upwardly and out of the first coating reservoir 148. The
second cavity 144 is arranged and configured to receive the second
die 160 and the third die 180. As previously noted, the first die
140 includes an annular groove 146 and first coating ports 108. As
shown, preferably, the first die 140 includes four first coating
ports 108 extending radially from the first coating reservoir 148
to the annular groove 146, such that each first coating port 108 is
perpendicular to adjacent first coating ports 108. This arrangement
of first coating ports 108 allows for coating material to be
supplied to the first coating reservoir 148 in a manner that
minimizes lateral forces exerted on an optical fiber disposed
within the first coating reservoir 148. Preferably, adjacent the
first coating reservoir 148 is a conical section 150 in which
viscoelastic forces begin to form, thereby assisting in centering
the optical fiber. Adjacent the conical section 150 is the first
land 152. The first land 152 is arranged and configured such that
the viscoelastic forces developed within the first land 152 center
the optical fiber. The viscoelastic forces formed in the first land
152 maintain proper centering of the optical fiber throughout the
applicator assembly 100.
[0033] The second cavity 144 of the first die 140 is arranged and
configured to receive the second die 160 (FIG. 5). As previously
noted, the first die 140 includes second coating ports 110 that are
aligned with corresponding second coating ports 110 disposed in the
body portion 102. As will be discussed in greater detail
hereinafter, the second coating ports 110 of the first die 140 are
further aligned with second inlets 164 formed in the second die
160. As well, the first die 140 includes third coating ports 112
aligned with corresponding third coating ports 112 formed in the
body portion 102 (FIG. 7). The third coating ports 112 are further
aligned with third coating inlets 184 (FIG. 11).
[0034] As shown in FIG. 5, the second die 160 includes a second
coating reservoir 162, second inlets 164, and a second land 166. As
noted above, the second inlets 164 are in fluid communication with
the second coating source 105 by way of the second coating ports
110. As such, the second coating reservoir 162 applies a second
coat of material to the first coat of material applied to the
optical fiber in the first coating reservoir 148 and sized by the
first land 152.
[0035] As shown in FIG. 6, the third die 180 includes a third
coating reservoir 182, third coating inlets 184, and a third land
186. The third die 180 is received within the second die 160 such
that the third inlets 184 are in fluid communication with the third
coating ports 112 of the second die 160, as best seen in FIG. 8. As
the optical fiber passes through the third coating reservoir 182,
coating material is applied to the second coat of material on the
optical fiber. The optical fiber next passes through the third land
186, which is sized such that the diameter of the layer of the
third coating can be adjusted by controlling the pressure of the
third coating source 106. Preferably, the third die 180 and the
second die 160 are secured in position by passing threaded
fasteners through the retention flanges 168 on both of the dies 160
and 180 and threadably engaging mounting holes (not shown) disposed
in the first die 140.
[0036] With reference to FIG. 7, the coating process of an optical
fiber 11 (as shown in FIG. 2A) using an embodiment of an applicator
assembly 100 is discussed. The optical fiber 11 passes through the
entrance die 130 and into the first coating reservoir 148 where the
primary coating material is contained under pressure. The diameter
of the entry land 132 is preferably chosen such that it is
sufficient to avoid optical fiber 11 impingement thereon and
sufficiently narrow such that the pressurized primary coating
material in the first coating reservoir 148 is effectively
contained, rather than rising up through the entry land 132. As
well, the diameter of the entry land 132 is selected such that air
is prevented from entering the first coating reservoir 148 and
therefore the primary coating layer 32. The pressure at which the
primary coating material is applied serves two purposes including
sealing the primary coating material against the optical fiber 11
at the entry land 132, thereby preventing bubble entrainment, and
pushing the primary coating material through the first land 152 to
help maintain the diameter of the primary coating layer 32.
[0037] After passing through the first primary land 152, the
optical fiber 11 enters the second coating reservoir 162 where a
layer of color coating material is applied to the primary coating
layer 32. As shown, the second coating reservoir 162 is formed
between the first die 140 and the second die 160, adjacent the
first land 152. The second coating reservoir 162 is fed by the same
second coating source 105. Next, the optical fiber 11 enters the
third coating reservoir 184 where a layer of secondary coating
material is applied to the color coating layer 34. The third
coating reservoir 184 is fed by the third coating source 106.
[0038] The applicator assembly 100 (FIG. 3) can also be used to
produce the embodiments of coated optical fiber 30B and 30C, as
shown in FIGS. 2B and 2C, respectively. The process used to create
coated optical fiber 30B (FIB. 2B) is similar to the process
discussed above with the exceptions that the color coating material
is applied to the optical fiber 11 in the first coating reservoir
148, the primary coating material is applied to the color coating
layer 34 in the second coating reservoir 162, and the secondary
coating material is applied to the primary coating layer 32 in the
third coating reservoir 182. The color layer 34 of coated optical
fiber 30B actually functions as a primary layer in that it is
applied directly to the optical fiber 11. In this instance, the
modulus of the color coating material is preferably less than or
equal to the modulus of the primary coating layer 32. For coated
optical fiber 30C (FIB. 2C), the primary coating material is
applied to the optical fiber 11 in the first coating reservoir 148,
the secondary coating material is applied to the primary coating
layer 32 in the second coating reservoir 162, and the color coating
material is applied to the secondary coating layer 36 in the third
coating reservoir 182.
[0039] FIG. 8 is a cross-sectional view of the applicator assembly
100 taken along line 88 of FIG. 3, showing the entire cross
section. FIGS. 9-11 are detailed cross sections of the first die
140, the primary die 160, and third die 180, respectively, as shown
in FIG. 8 and are presented for clarification of the structure of
the applicator assembly 100. Note, although FIGS. 3-11 show the
primary coating applied in a single layer, there is no intention to
limit the applicator assembly to this configuration only. For
example, embodiments are envisioned wherein the primary coating
layer 32 is applied in at least two adjacent layers, such as in the
first coating reservoir 148 and the second coating reservoir 162.
This process may offer various manufacturing advantages that are
discussed in pending U.S. application Ser. No. 10/376,898, entitled
"MULTIPLE FEED APPLICATOR ASSEMBLY FOR COATING OPTICAL FIBERS,"
which is incorporated herein by reference. As well, application of
the primary coating material in at least two adjacent layers
requires the addition of at least one additional coating reservoir
(not shown) to the applicator assembly so that the color coating
materials and secondary coating materials can be applied.
[0040] The applicator assembly for applying a primary coating, a
secondary coating and a color coating to an optical fiber can also
be viewed as providing a method of applying a primary coating, a
secondary coating and a color coating to an optical fiber. In this
regard, as shown in FIG. 12, a representative method can be broadly
summarized by the following steps: applying a layer of the primary
coating to the optical fiber (as shown in block 202), applying a
layer of the color coating to the optical fiber (as shown in block
204), and applying a layer of the secondary coating to the optical
fiber, wherein the layers of primary coating, secondary coating,
and color coating are each applied prior to the other layers being
cured (as shown in block 206).
[0041] It should be emphasized that the above-described embodiments
are merely possible examples of implementations. Many variations
and modifications may be made to the above-described embodiments.
All such modifications and variations are intended to be included
herein within the scope of this disclosure and to be protected by
the following claims.
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