Fiber curvature measurement fixture

A fixture for use in a fiber curl measurement assembly has a fiber guide plate upon which are disposed a pair of fiber locating and centering rods which form a V-groove for containing the fiber, which is free to rotate within the groove. A reference plate having a transverse reference edge in space from the downstream end of the V-groove a distance sufficient for fiber curvature to be measured during rotation. A rotating stage under control of a motor has a rotatable plate upon which rests, and is held, a fiber clip for containing the fiber to be measured. The rotating stage is oriented at a vertical angle to the plane of the rods and V-groove, and the fiber is threaded through a bearing block into the V-groove. The bend thus created in the fiber is such that a downward force is created on the fiber to hold it within the V-groove. Thus, where the rotating stage is rotated by the motor, the fiber within the groove is rotated so that curl measurements may be made. The diameter of each of the rods is such that the fiber is cammed into the V-groove during the threading operation.

FIELD OF THE INVENTION 
This invention relates to the measurement of optical fiber curvature or 
curl, and, more particularly, to a fixture for holding the optical fiber 
under test during measurement of the curl. 
BACKGROUND OF THE INVENTION 
Fiber curl is the inherent tendency of a length of uncoated fiber to 
exhibit some degree of curvature. Heretofore, such curvature has not 
presented a problem inasmuch as connections to or splicing of, most 
optical fibers has been on an individual fiber basis, generally using 
active alignment devices. However, because of the enormous increase in the 
use of optical fibers for communications signal transmissions, it has been 
necessary to find ways of treating, e.g., splicing, fibers en masse. Thus, 
there have evolved passive alignment technologies which optimize fiber 
alignment for groups of fibers, such as ribbon cables. The random 
orientation of the curvature of individual fibers within such a ribbon can 
cause misalignment of fibers in the mass splicing operation. The problem 
of such misalignment is exacerbated in the field, where the technician 
lacks the necessary equipment to correct for it. As a consequence, fiber 
manufactures have sought ways to quantify and control the amount of 
curvature in their fibers in order that end users of the fiber can be 
assured that fiber curl will not adversely impact the splicing efficiency 
or yields of their mass splices. In addition, monitoring of fiber curl 
during the manufacturing process helps to supply a feedback to the 
operators of the up-stream processes in the fiber fabrication, thus making 
it possible to minimize yield losses resulting from too great fiber curl 
by adjusting these processes to reduce curl. 
As a prerequisite for quantiignd and controlling fiber curl, a method for 
measuring such curl is necessary. In the prior art there have been 
numerous arrangements for determining or, more particularly, measuring 
fiber curl, as exemplified by one such method as shown and described in an 
article entitled "Straightening Out the Fiber Curl Problem", by J. Farro 
and K. Erng, Photonics Spectra, September 1993, at pages 102 through 108. 
The apparatus shown therein comprises a V-groove holder such as a vacuum 
chuck, or a ferrule, for holding the fiber under test on a constant axis 
that allows rotation of the fiber through three hundred and sixty degrees 
(360.degree.). The fiber may be rotated either manually or by a stepping 
motor arrangement which rotates a fiber holder relative to the ferrule or 
vacuum chuck. Fiber deflection from the axis as it is rotated is measured 
by, for example, a viewing microscope or some type of optical measuring 
instrument, such as a laser micrometer. Additionally, an image analysis 
system, a video camera and monitor, or a video analyzer and computer may 
be used. To make the measurements, the fiber is placed in the ferrule or 
vacuum chuck with a ten to twenty millimeter (10-20 mm) overhang. As the 
fiber is rotated, as by the stepping motor, preferably in fifteen degree 
(15.degree.) increments, the magnitude of the fiber excursions is 
measured. The data obtained are fitted to a sine function to determine 
peak-to-peak amplitude, which indicates, by proper calculation, the radius 
of curvature of the fiber. With the overhang known, and the maximum 
deflection measured, the fiber's radius of curvature can be obtained from 
a simple circular model. Such an arrangement has been used to determine 
the radius of curvature or of large numbers of fibers with good or 
satisfactory accuracy. However, while the method discussed, or variations 
thereof, is in wide use because of its relative simplicity, the apparatus 
presents certain problems which, in a production environment, can be 
costly. For example, the vacuum chuck constantly draws dirt particles into 
its fiber holding groove. This problem is mentioned in the foregoing Farro 
and Ernig article. The apparatus must be shut down periodically while the 
chuck is cleaned. As a result of dirt accumulating in the grooves, the 
vacuums' force decreases and the fiber is not held at a constant axis, 
thereby inducing measurement errors. Additionally, each time a new fiber 
is to be introduced into the apparatus, the vacuum force must be cut off 
while the fiber is placed in the chuck groove. 
The use of a ferrule in place of a vacuum chuck introduces different 
problems. The fiber must be inserted slowly and rotated gently during 
insertion to avoid breakage, which is a tedious, tiring and slow process 
for the operator. If a fiber break occurs within the ferrule, it is quite 
difficult to remove it because of the extremely small diameters involved. 
Thus, each of the accepted methods of holding the fiber presents its own 
problems, with the net result of slowdowns and interruptions in the 
production process. 
SUMMARY OF THE INVENTION 
The present invention is a fiber holding and rotating fixture for use in 
fiber curl measurements that is easy to use and that is not subject to 
most of the problems of the prior art devices. More particularly, the 
fixture comprises a base member having an axis and upon which is mounted a 
reference plate having a straight knife edge normal to the axis. Axially 
spaced from the knife edge is a guide plate having a shoulder on the top 
surface thereof that extends parallel to the axis. First and second 
longitudinal magnetic guide pins rest on the top surface and abut each 
other, with one of the guide pins magnetically held against the shoulder 
and the two pins magnetically held together. The line of abutment or 
contact of the pins with each other defines an axial groove for containing 
the optical fiber. The guide plate has retaining members for holding the 
pins in place longitudinally while the pins are held in contact with each 
other by the magnetic force. A hinged lid is adapted to bear against the 
tops of the guide pins without interfering with a fiber in the axial 
groove. 
An angled bearing block has a rotating stage and a grooved pulley extending 
therefrom which are axially aligned with the guide pin groove at an angle 
thereto. The rotating stage is a flat member having a longitudinally 
extending guide shoulder for aligning a fiber holding clip and having a 
motor mount extending from one side of the bearing block on which a motor 
is mounted. A fiber guide is mounted to the rotating stage and passes 
through the angled bearing block on an axis normal thereto and alignment 
with the guide pin groove, so that fiber passed through the guide is 
aligned with, and, as will be discussed more fully hereinafter, rests in 
the groove formed by the two guide pins. The knife edge of the reference 
plate is spaced from the point where the fiber exits the groove a distance 
of, for example, twenty millimeters (20 mm) and the knife edge serves as a 
reference mark for the point of measurement on the fiber. In operation, 
the rotating stage rotates the fiber clip and the fiber contained therein 
so that deviations of the free end of the fiber from the axis can be 
measured in steps through three hundred and sixty degrees, and the 
necessary computations performed to determine fiber curl. 
The fixture of the present invention is, as will become apparent, easy to 
use, substantially eliminates the problems of breakage and accumulated 
dirt, and requires no unusual skill or dexterity on the part of the 
operator. Production shut down times are, as a consequence, minimized, 
with attendant economic benefit.

DETAILED DESCRIPTION 
As discussed hereinbefore, an uncoated, unconstrained length of optical 
fiber can have sufficient curvature to cause serious alignment problems in 
automated mass fusion splicing equipment. The mass splicing techniques, 
which require the alignment of as many as twenty-four (24) fiber ends 
(twelve splices) can tolerate only limited offset between fiber ends. 
Typically, a mass fusion splicer has a fiber unconstrained distance of 
about three millimeters (3 mm) and can tolerate a fiber end which is 
offset about three and one-half microns (3.5 .mu.m) from where a perfectly 
straight fiber would be. If an accurate determination of the radius of 
curvature of the fiber is made, this condition can be met. The technique 
for such determination involves measuring the fiber's offset at a point 
approximately twenty millimeters (20 mm) from the point where the fiber 
becomes unconstrained, i.e. a distance x, rotating the fiber through three 
hundred and sixty degrees (360.degree.) and viewing the fiber end movement 
transverse to the axis of rotation and viewing the fiber end transverse to 
the axis of rotation to obtain the maximum offset y. The radius of 
curvature R is then given by 
##EQU1## 
In FIG. 1 there is shown diagrammatically, an apparatus 11 for making these 
measurements. Apparatus 11 comprises a fixture 12 for holding the fiber 
sample 13 with an unconstrained length x of 20 mm. Fixture 12 may 
comprise, in prior art systems, a ceramic ferrule as shown, or a vacuum 
chuck, or other type of holding device that is rotatable or that permits 
rotation of the fiber. A white light source 14 supplies illumination for a 
CCD camera 16 or other reviewing device. 
The shaft of a stepping motor 17 is connected through a pulley 18 and belt 
19 to a second pulley 21 upon which is mounted, and revolvable therewith, 
a fiber holder 22. The fiber holding fixture 12 has a longitudinal bore 
having a diameter of approximately 127 microns into which is inserted the 
fiber 13. In practice the fiber sample may be approximately six inches 
long, with approximately four inches of the coating removed. 
In operation, the sample is rotated one full revolution in nine degree 
(9.degree.) increments so that the transverse image of the fiber may be 
viewed and the axial offset observed and recorded. A simple calculation of 
one-half the highest and lowest offset gives the value y in Equation (1), 
and the radius R can be readily determined. Alternatively, y can be 
obtained by fitting a sine wave to the offset fiber centers. A computer or 
other processing unit 23 may be used to analyze the video image. 
As was pointed out hereinbefore, prior art fiber holding devices or 
fixtures 12 have been somewhat less than completely satisfactory. In FIGS. 
2 and 3 there is shown the holding fixture 25 of the invention for use in 
a measuring system as shown in FIG. 1 while, as will be apparent 
hereinafter, is a substantial improvement over the prior art. Fixture 25 
comprises a scope plate 26 and scope knee 24 upon which may be mounted a 
viewing microscope, not shown. A Y-saddle member 27 straddles plate 26, 
and is affixed thereto by, for example, bolts (not shown) through bolt 
holes 28 which are elongated to allow alignment adjustments. Y-saddle 
member 27 has mounted thereon an X-stage plate member 29, affixed thereto 
by bolts (not shown) through bolt holes 31, also elongated for 
adjustments. As seen in FIGS. 2 and 3, one end of plate member 29 has an 
angled surface 32 upon which is mounted a bearing block 33, upon one end 
of which is a motor plate 34 which, in turn, supports a motor arm 36 and 
step motor 37. The shaft of motor 37 extends, for example, through a 
bushing, not shown, through motor plate 34 and terminates in a pulley 38. 
A second pulley 39 is spaced from pulley 38 and has a hollow shaft 40, 
which extends, in bushing 41, through bearing block 33 and is aligned with 
the centerline or axis of the fixture 25. Pulley 39 is driven by pulley 38 
and hence motor 37 by means of endless belt 42. Mounted on the face of 
pulley 39 and rotatable therewith is a guide member 43 which has affixed 
thereto a rotatable plate 44. Member 43 and plate 44 together form a 
rotating stage for holding a standard fiber clip 45, which is held in 
place on plate 44 by means of one or more magnets 46 contained in plate 
44. Means 47 on plate 44 aligns the fiber clip 45 so that a fiber 48 held 
thereby is aligned with the axis of the fixture 25. As will be more 
apparent hereinafter, the fiber 48 is passed through a fiber guiding 
member such as an extended nose portion 49 of guide member 43 which is 
held against longitudinal movement by means of a lock collar 50. As thus 
far described, in operation, the rotating stage with the fiber clip 45 in 
place thereon and a fiber in the clip rotates the clip and fiber, so that 
the fiber 48 emerging from nose 49 rotates. 
Mounted in a groove 51 in X-stage plate 29 is a guide stage 52 which 
comprises a first guide plate 53 having mounted thereon a reference plate 
54 which has a reference knife edge 56 extending transverse to the axis of 
the fixture 25. Plate 53 has a longitudinally extending slot 57 for 
receiving a tongue member 58 on the bottom of a second guide plate 59 for 
axially aligning it. As will be more clearly seen hereinafter, the top 
surface of plate 59 receives and aligns two metallic guide pins 61 which 
are held in place by means of one or more magnets 55, and which are held 
in place longitudinally by rod keeper 62. Pins 61 are forced together by 
the magnetic attraction to form a longitudinal fiber receiving groove 
aligned with the axis of the fixture 25. A hinged closure plate 63 bears 
against the upper surfaces of the pins 61 when it is closed and functions 
to maintain the fiber 48 within the groove. Plate 59 has a downstream end 
spaced from knife edge 56, and an upstream end adjacent the front face of 
bearing block 33. A set-up gage 65 is used to align and space the 
component parts of the apparatus 25. 
FIG. 3, which is an exploded perspective view of the fixture 25, makes 
clear the relationships of the various components, and, in most cases, 
their configurations. For simplicity, the numerous bolts or other holding 
or mounting devices have not been shown. 
FIGS. 4 and 5 depict the action of the pins or rods 61 on the fiber 48 for 
centering the fiber 48 and maintaining it in proper alignment during 
rotation thereof. In FIG. 4, the dashed line 60 represents the line of 
contact of the two rods 61, thereby forming, in effect, a V-groove 64 as 
seen in FIG. 5. The end of nose portion 49, from which fiber 48 is 
emergent, directs the fiber at an angle .O slashed. into V-groove 64 where 
the inherent stiffness of the fiber 48 is such, as to cause it to bear 
against the V-groove 64 along its length, as shown in FIG. 4. Thus, fiber 
48 may be fed through nose portion 49 of guide member 43 into V-groove 64, 
where it tends to remain even while being rotated. If, as expected, the 
fiber 48 has a bend thereon, it may not immediately center itself within 
V-groove 64, instead riding along the top of one of the rods 61, as shown 
at A in FIG. 5. As long as the fiber is on the V-groove side of the rod 
centerline, the fiber will be cammed down into V-groove 64 as it is pushed 
along the rod 61. This action is similar to, and based upon the same 
principles as, the arrangement shown in U.S. Pat. No. 5,787,216 of Bice et 
al. It has been found that excellent results are obtained when the rods 61 
are each approximately 0.0625 to 0.0626 inches in diameter, which is 
approximately twelve to fourteen times the diameter of the fiber which may 
be, for example, 125 microns (125 .mu.m). In general, a rod diameter range 
of eleven to twenty-five times the diameter of the fiber will produce good 
results. However, the narrower range gives optimum performance. 
In operation, a fiber 48 to be tested is inserted into fiber clip 45, which 
may take any of a number of commercially available forms. The clip 45 is 
placed upon rotatable plate 44 and the fiber threaded or passed through 
guide member 43 and nose portion 49, which passes through bearing block 
33. As can be seen, bearing block 33 is mounted on x-stage plate 29 at an 
angle .O slashed. thereto. Fiber 48 is fed forward until it emerges from 
nose portion 49 and settles into the V-groove 64 formed by the rods 61 in 
the manner shown in FIGS. 4 and 5. Fiber 48 is fed forward until the end 
thereof extends above and just beyond the knife edge 56 on reference plate 
54, but not in contact therewith. Measurements are then made as the 
rotating stage formed by guide member 43 and plate 44 is rotated by step 
motor 37, pulleys 38 and 39, and belt 42, thus rotating fiber 48. The 
distance x from the ends of rods 61 to knife edge 56 is the distance 
spanned by the free fiber 48, and is generally in the range of ten to 
twenty millimeters (10-20 mm), and is the side-to-side movement of this 
portion of fiber 48 that, when measured, yields to necessary data for 
determining the radius of curvature, which may be done in a processing 
unit or computer 23, as shown in FIG. 1. During rotation, fiber 48 is 
constrained from slipping out of V-groove 64 by means of hinged closure 
plate 63. 
The fixture of the invention thus aligns and restrains the fiber during 
rotation without the numerous disadvantages of prior art arrangements such 
as ferrules or vacuum chucks, or other such holding devices of the prior 
art. The fixture of the invention allows quick and simple insertion of the 
fiber in proper position, and materially reduces the risk of fiber 
breakage. Even if a break does occur, the fiber pieces are accessible and 
easily removed. 
FIGS. 6 through 15 are depictions of several of the individual components 
of the fixture 25 for a clearer understanding of certain aspects of the 
invention. 
FIGS. 6a through 6d depict the Y-saddle member 27 and are perspective, 
plan, side elevation, and rear elevation views, respectively thereof. 
Member 27 has, on the bottom thereof, a first groove 66 for receiving a 
scope plate 26 so that, when assembled, member 27 straddles plate 26, as 
best seen in FIG. 2. A second groove is formed on the top of member 27 by 
means of projections 68. Elongated bolt holes 69 are provided for allowing 
a measure of adjustment when the parts are assembled. Member 27 is 
preferably made of suitable metal, such as, for example, aluminum. 
FIGS. 7a through 7d depict the x-stage plate 29 and are perspective, plan, 
end elevation, and side elevation views, respectively thereof. 
X-stage plate 29, is dimensional to fit within the second groove 67 of 
Y-saddle member 29, and to be bolted thereto through elongated bolt holes 
31. Plate 29 has an elongated groove 51 formed on the top surface thereof 
for receiving guide stage plate 53, and, at one end thereof, transverse 
groove 71 have a transversely extending angled surface 32, which is at an 
angle .O slashed. to the top surface of plate 29. In practice, it has been 
found that a value of .O slashed. of eighteen to twenty-two degrees 
(18.degree.-22.degree.) produces excellent results. Plate 29 is preferably 
made of metallic material such as, for example, aluminum or steel. 
The guide stage plate 53 is shown in FIGS. 8a through 8d, which are, 
respectively, perspective, plan, side elevation, and end elevation views 
thereof. 
Guide stage plate 53 is dimensional to fit within groove 51 of x-stage 
plate 29. Plate 57, which is preferably of metallic material, such as, for 
example, aluminum, has a longitudinally extending slot 57 on the top 
surface thereof for locating and aligning guide plate 59 by means of 
tongue member 58 on the bottom thereof. 
Guide plate 59 is shown in FIGS. 9a through 9e which are, respectively, 
perspective, top plan, front elevation, bottom plan, and side elevation 
views thereof. In FIGS. 9b and 9d it can be seen that tongue member 58, 
which extends along the length of the bottom surface of plate 59 has a 
centerline which defines, or is coincident with the centerline of the 
fixture 25 when assembled. Tongue member 58 is dimensioned to fit within 
longitudinal slot 57 in guide stage plate 53, thereby centering guide 
plate 59, which is bolted to plate 53 by means of a bolt, not shown, in 
bolt hole 72. Extending along the top surface is an aligning member 
comprising a shoulder 73 which is spaced from, and parallel to, the 
centerline. The distance between shoulder 73 and the centerline is 
approximately equal to the diameter of a rod or pin 61, which, as shown in 
FIG. 2, bears against shoulder 73. With both rods 61 in place as shown in 
FIG. 2, the V-groove 64 formed thereby extends along the centerline. Rods 
61 are held against each other and against shoulder 73 by means of magnet 
55, shown in FIG. 3, which is housed in a bore 74, the center of which is 
offset from the centerline with its center roughly aligned with one edge 
of tongue member 58, and the shoulder 73. The offset position of magnet 55 
causes it to pull a first one of the rods 61 of magnetic material firmly 
against the shoulder 73 and the second rod firmly against the first rod, 
thereby insuring that the V-groove 64 is properly aligned and firmly 
positioned. On one side, or end, of plate 59 is a first projecting stop 76 
which helps hold the rods 61 in position longitudinally, and a second stop 
77 which functions to guide the rods into position during assembly. On the 
opposite edge of plate 59 are bolt holes 78 which enable rod keeper 62, 
shown in FIG. 3, to be mounted in position to function as a longitudinal 
stop for the rods 61. A pair of spaced projecting ears 79 extend from one 
side of plate 59 above the top surface thereof, as shown, and are bored to 
receive a hinge pin 81 mounted to hinged closure plate 63. With the rods 
mounted in this way, they are readily accessible and removable for 
cleaning or replacement without disturbing the remainder of the fixture. 
FIGS. 10a through 10d are a first perspective, a second perspective, a 
front elevation, and a bottom plan view, respectively, of the closure 
plate 63. Plate 63 has a rearwardly extending hinge tang 82 which has a 
bore 83 extending therethrough for receiving hinge pin 81. If desired, 
bushings 84, shown in FIG. 3, may be used in bore 83 to insure smooth 
operation of the hinge arrangement. Projecting from the underside of plate 
63 and extending from one end to the other thereof is a fiber keeper 
member 86 which, when plate 63 is in its closed position, bears against 
the tops of rods 61, thereby keeping the fiber in place within V-groove 
64. A notch 87 may be cut into the lower edge of what is the fiber 
entrance end to minimize possible rubbing of the rotating fiber during 
operation. Additionally, a fiber restraining means such as a resilient pad 
88, preferably of a material such as velvet, may be affixed to keeper 86 
at the fiber exit end for keeping the fiber from climbing out or bouncing 
in the V-groove. Thus, it is made at least partially immune to rough edges 
in the V-groove or dirt on the fiber. In practice, the plate 63 is in its 
closed position and assists in grinding the fiber into the V-groove when 
being inserted. The pad 88 protects the fiber and actually cleans it as it 
is inserted. Other fiber restraining means, such as a rotatable member, 
might be used instead of pad 88. 
Bearing block 33, which is depicted in FIGS. 11a through 11d which are, 
respectively, perspective, side elevation, front elevation, and bottom 
plan views thereof, is adapted to be mounted along its bottom edge on 
angled surface 32 of x-stage plate 29, as shown in FIG. 2, by means of 
bolt holes 89 and suitable bolts, not shown. Block 33 has a central bore 
91 extending therethrough the centerline of which will be at an angle .O 
slashed. relative to the surface guide plate 59 when block 33 is affixed 
to plate 29. Block 33 also has bolt holes 92 for mounting motor arm 36 
thereto. 
In FIGS. 12a through 12e, which are, respectively, perspective, top plan, 
side elevation, end elevation, and bottom plan views of the rotatable 
plate 44 upon which fiber clip 45 is to be carried. Plate 44 has, on the 
top surface thereof, a longitudinally extending alignment member 47, and, 
extending from the bottom, a built-out portion 93 for housing one or more 
magnets 46 in bore 94. As can be seen, magnet 46 is held in position under 
alignment member 47. As a consequence, when a fiber clip 45, of magnetic 
material, is placed against alignment member 47, it is held there by 
magnetic attraction. The spacing of member 47 from the centerline of plate 
44 is such that the fiber 48 held by clip 45 will be centered along the 
operative axis of the fixture. The centerline of plate 44 aligned with the 
axis of plate 53 and is at the angle .O slashed. relative thereto. Plate 
44 also has, at one end thereof, bolt holes 96 for mounting guide member 
43 thereto. 
The guide member 43 is shown in FIGS. 13a through 13d which are, 
respectively, perspective, plan, rear elevation, and cross-sectional views 
thereof. Member 43 comprises a block of suitable material adapted to be 
mounted on rotatable plate 44 at one end thereof by means of bolts, not 
shown, in countersunk bolt holes 97, and the assembly is mounted to pulley 
39 by means of bolt hole 98 and a suitable bolt, not shown. Member 43 has 
extending therefrom a nose portion 49 which, as best seen in FIG. 13d, has 
a bore 99 extending therethrough. FIG. 13d is a cross-sectional view along 
the line I--I in FIG. 13c. Bore 99 has a first tapered section 101 and a 
second tapered section 102 for ease of threading the fiber 48 into the 
straight section 103 of the bore 99. As discussed hereinbefore, nose 
portion 49 extends through block 33 in hollow shaft 40, as shown in FIG. 
3, and is preferably locked against longitudinal movement by lock collar 
50. The centerline of bore 99 is aligned with V-groove 64 so that fiber 48 
may be placed and held therein, as shown in FIG. 4. With such an 
arrangement, the nose portion 49 functions as a fiber holding and guiding 
device, and the fiber and portion 49 rotate together. Although nose 
portion 49 bears some resemblance to prior art ferrule arrangements, in 
those devices the fiber rotates within the ferrule, with a consequent 
possibility of fiber wear or abrasions, or other damage. Guide member 43 
is held in place on pulley 39 by only the one bolt in bolt hole 98. As a 
consequence, when it, or nose portion 49, becomes dirty or plugged, it may 
be quickly and easily replaced. 
In concluding the detailed description, it should be noted that it will be 
obvious to those skilled in the art that many variations and modifications 
may be made to the preferred embodiment without substantial departure from 
the principles of the present invention. All such variations and 
modifications are intended to be included herein as being within the scope 
of the present invention, as set forth in the claims. Furthermore, in the 
claims, the corresponding structures, materials, acts, and equivalents of 
all means or step plus function elements are intended to include any 
structure, material, or acts for performing the functions with other 
claimed elements as specifically claimed.