U.S. patent application number 12/197162 was filed with the patent office on 2008-12-11 for optical and electrical hybrid connector.
Invention is credited to David A. Benaron, Michael R. Fierro, Marvin K. Hutt, Ilian H. Parachikov.
Application Number | 20080304793 12/197162 |
Document ID | / |
Family ID | 35784331 |
Filed Date | 2008-12-11 |
United States Patent
Application |
20080304793 |
Kind Code |
A1 |
Benaron; David A. ; et
al. |
December 11, 2008 |
Optical and Electrical Hybrid Connector
Abstract
An improved hybrid connector for rapidly, reliably, and
reversibly making mixed optical and electrical connections has a
male plug with one or more centrally located optical fibers
centrally located inside an elongated shaft of a male plug, and one
or more electrical contact elements are located on the peripheral
surface of the shaft, and a socket with electrical contacts, and a
floating optical connector. Insertion of the elongated shaft into
the socket connects the electrical contacts of the shaft and socket
and couples the fibers of the shaft with optical fibers in the
floating optical connector.
Inventors: |
Benaron; David A.; (Portola
Valley, CA) ; Parachikov; Ilian H.; (Belmont, CA)
; Fierro; Michael R.; (Los Gatos, CA) ; Hutt;
Marvin K.; (Oakland, NJ) |
Correspondence
Address: |
MORGAN, LEWIS & BOCKIUS, LLP.
2 PALO ALTO SQUARE, 3000 EL CAMINO REAL
PALO ALTO
CA
94306
US
|
Family ID: |
35784331 |
Appl. No.: |
12/197162 |
Filed: |
August 22, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11154023 |
Jun 15, 2005 |
7427165 |
|
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12197162 |
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60580414 |
Jun 16, 2004 |
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Current U.S.
Class: |
385/75 |
Current CPC
Class: |
H01R 2107/00 20130101;
G02B 6/3817 20130101; H01R 13/625 20130101; H01R 13/24 20130101;
H01R 24/58 20130101; G02B 6/3897 20130101 |
Class at
Publication: |
385/75 |
International
Class: |
G02B 6/38 20060101
G02B006/38 |
Claims
1-9. (canceled)
10. A medical illuminator catheter comprising: (a) a biocompatible
catheter sheath, said catheter sheath having a monitor end, a
central body, and a patient end; (b) an optical and electrical
hybrid male plug located at the monitor end of said catheter; (c) a
light source at the patient end of said catheter; (d) at least one
optical collection fiber for collecting light scattered from a
region illuminated by the light source and for transmitting said
collected light from said patient end of the catheter, along a
length of said catheter and into said male plug at the monitor end
of the catheter; and (e) power supply wires for transmitting
electrical power to said light source, said wires traversing a
length of said catheter and electrically connected to both said
light source and to contacts on said connection plug.
11-21. (canceled)
22. A medical illuminator catheter comprising: (a) a biocompatible
catheter sheath, said catheter sheath having a monitor end, a
central body, and a patient end; (b) a plug located at the monitor
end of said catheter for connecting the catheter to a monitor, a
cable functionally connected to a monitoring system, or wireless
connection to a wireless network; (c) a light source at the patient
end of said catheter; (d) at least one optical collection fiber or
optical element for collecting light scattered from a region
illuminated by the light source and for transmitting said collected
light or a signal derived from said collected light, from said
patient end of the catheter, along at least a portion of a length
of said catheter and into at least one of said male plug at the
monitor end of the catheter, light detector, or spectrometer; and,
(e) power supply wires for transmitting electrical power to said
light source, said wires traversing a length of said catheter and
electrically connected to both said light source and to contacts on
said connection plug.
23. The catheter of claim 24, further comprising a memory
information chip configured for retaining information useful in the
operation of the device.
24. The catheter of claim 24 wherein the catheter further comprises
a socket and wherein further said socket has an alignment pin, said
shaft has an L-shaped channel for receiving said alignment pin and
preventing rotation of said shaft during axial insertion into said
socket, said shaft having a flat region with said peripheral
electrical contact elements further arranged so as not to make
electrical contact with said socket contacts during said axial
insertion and further arranged so as to make electrical contact
with said socket electrical contacts after the shaft is fully
inserted and rotated when the pin is at the end of the elongated
channel.
25. The catheter of claim 24 wherein the catheter is configured to
function as an oximeter probe.
26. The catheter of claim 10, further comprising a memory
information chip configured for retaining information useful in the
operation of the device.
27. The catheter of claim 10, wherein the catheter further
comprises a socket and wherein further said socket has an alignment
pin, said shaft has an L-shaped channel for receiving said
alignment pin and preventing rotation of said shaft during axial
insertion into said socket, said shaft having a flat region with
said peripheral electrical contact elements further arranged so as
not to make electrical contact with said socket contacts during
said axial insertion and further arranged so as to make electrical
contact with said socket electrical contacts after the shaft is
fully inserted and rotated when the pin is at the end of the
elongated channel.
28. The catheter of claim 10, wherein the catheter is configured to
function as an oximeter probe.
Description
RELATED APPLICATION
[0001] This application claims priority to Provisional Patent
Application Ser. No. 60/580,414, filed on Jun. 16, 2004, the
disclosure of which is hereby incorporated by reference in its
entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to plug and socket connector
systems for providing inexpensive, reversible, axial-position-error
tolerant (Z-tolerant) mixed optical and electrical connections, and
more particularly to a quick-insertion, non-shorting, rotationally
engaged, shaft and socket connector having one or more Z-tolerant
float-coupled optical fibers located centrally inside an elongated
shaft, and one or more Z-tolerant wide electrical contact array
elements located on a flexible PC board mounted peripherally on the
same shaft, for the purpose of creating reversible
optical/electrical hybrid connections, thus avoiding much of the
expense, awkwardness, and required axial precision inherent in
conventional hybrid connector systems.
BACKGROUND OF THE INVENTION
[0003] The traditional optical or electrical connector is a
monolithic device, optimized for the delivery of a single signal
type--either optical or electrical. There are reasons for this
traditional separation of connectors by signal type. First, most
applications require only one type of transmitted signal, and thus
do not demand the additional design and materials expense involved
in hybrid connections. Second, inherent features required for good
electrical connections (e.g., good physical contact with contact
element wiping, low axial positional mating accuracy, and no need
of contact finishing after assembly) are different, and often
contrary, to those features required for good optical fiber
coupling (avoiding physical contact which damages fiber faces, high
axial positional mating accuracy, and required post-assembly
fiber-end finishing steps).
[0004] These limitations and requirements are best appreciated by
examining the source of such differences between optical and
electrical connections during mating and assembly.
[0005] First, consider the presence or avoidance of physical
contact during mating. Electrical connections generally require
good physical contact in order to achieve reliable, low-resistance
current flow. Metallic contacts also tend to accumulate surface
deposits and corrosion over time, so a "wiper" effect is usually
incorporated into the physical make-and-break actions to facilitate
ongoing contact cleaning. In contrast, good physical contact
between optical fibers is generally to be discouraged because the
layered glass faces of fibers are fragile. Direct physical contact
between optical fibers damages the cladding that keeps light within
the fibers, scratches the optical fiber face where light is
transmitted, or shatters the fiber body entirely, all of which
reduce fiber light transmission or renders the fiber useless.
[0006] Next, consider the axial (Z-axis) positional accuracy
required during mating. Electrical pin and socket connections, once
inserted part way, usually continue to work well as the elements
are pushed farther together. In fact, a bit of additional insertion
in electrical contacts usually leads to improved contact due to the
increased contact surface area and wiping effects. Therefore, there
is little Z-axis positional accuracy typically required to make an
electrical connection work well. This permits electrical contacts
to be manufactured cheaply in large arrays using low-axial-accuracy
metal pins and sockets, such as the standard D-pin connectors used
in the computer industry which have 9 to 100's of pins in a planar
(flat XY-axis plane perpendicular to the axis of insertion)
arrangement. Such planar electrical contacts typically also have
lateral pin wiggle--easily demonstrated in a 9-pin standard D-Pin
connector in which the male pins each show millimeter lateral
movement if physically perturbed.
[0007] In contrast, optical connectors are not so tolerant of
error. Fiber connections have lateral (XY-axis) and axial (Z-axis)
positional mating accuracy requirement as much as 1,000-fold more
precise than for the above-described electrical connections. An
optical fiber's tolerance for positional error is typically very
low for several inherent reasons. First, axial (Z-axis) movement of
optical fibers away from each other results in a loss of optical
coupling; while axial movement toward each other must be carefully
limited into order to prevent collisions between the fiber ends.
Such collisions can seriously damage most optical fiber faces.
Second, a seemingly minor lateral positional misalignment of a pair
of optical fibers typically leads to huge fiber coupling losses.
For illustration, a mere 0.004 inch lateral offset between a 100
micron pair of multimode fibers can lead to a complete loss of
transmitted light.
[0008] Because of this need for micron alignment between coupled
optical fibers, fiber connections typically require high-precision
components in the connector. These precision components--including
laser drilled ferrules and milled stainless-steel
couplers--translate to a high connector cost. For example, a pair
of industry-standard SMA-type optical plugs and central mating
dual-female coupler connector, allowing for the joining of only a
single pair of fibers, retails at many times the price of a pair of
25-pin D-type electrical array male/female connectors.
[0009] Third, one must consider the accessibility of the contacts
during assembly and finishing. Electrical pins are typically
shielded or hooded, and the sockets recessed, to prevent wire to
wire shorting. In contrast, optical fiber ferrules must typically
protrude beyond any protective holders in order to allow for fiber
finishing (such as gluing, sanding, and polishing) after a new,
bare optical connector is stuffed and glued with an optical
fiber.
[0010] All told, when taking into consideration the above inherent
limitations, electrical and optical connectors have physical
contact, positional accuracy, and post-assembly requirements that
come directly into conflict, and such conflicting requirements are
not readily simultaneously satisfied.
[0011] The above limitations of conventional connectors are
apparent in the art.
[0012] Hybrid optical and electrical connectors are known. Such
deployments are most typically planar (XY-axis), in which the
mating elements form a face that is flat and perpendicular to the
axial mating axis. For example, WO 01/042839 and U.S. Pat. No.
6,612,857 teach independent detachable electrical or optical
assemblies that are combined into a single hybrid connector. U.S.
Pat. No. 6,599,025 teaches a hybrid with the optical fiber
positioned between the electrical elements of a standard connector.
U.S. Pat. No. 6,588,938 teaches a hybrid housing with planar arrays
of electrical contact maintained by springs. An independent element
hybrid commercial product is known (Miniature F7 Contact for Multi
and Hybrid Fibre Optic Connectors, Lemo, Switzerland). These Lemo
connectors, by failing to simultaneously optimize the different
requirements of optical and electrical connections through
Z-tolerance, remain expensive (greater than US $100 per connector).
All of these hybrid devices remain simple, non-optimized devices
that suffer from the drawback that they use independent, standard,
planar coupling elements without optimization of the differing and
conflicting electrical and optical mating requirements, and do not
suggest or teach a need for increased axial tolerance, all of which
is required for low-cost simultaneous mating of both the electrical
and optical signals.
[0013] Axial (Z-axis) deployment of the electrical contacts along a
shaft is a known, though uncommon, alternative to planar contact
deployment. U.S. Pat. No. 4,080,040 teaches a longitudinal (axial)
arrangement of multiple electrical contact elements along a
patch-cord plug and receiving jack, but does not teach how to
reduce the axial positional accuracy requirements of the connector
through use of floating or lens-coupled elements for fibers in a
hybrid design. Combination of this or other axial plug and socket
arrangements with optical fibers, as is taught in the cited hybrid
connectors above, would be insufficient to achieve Z-tolerance, as
a need for Z-tolerant elements to increase axial tolerance is
neither taught nor suggested in either body of art.
[0014] Optical elements facilitating good fiber coupling along with
reduced axial mating accuracy are known. U.S. Pat. No. 5,259,052
teaches a limited-movement floating ferrule that is used to couple
two fiber optic plugs. U.S. Pat. No. 6,550,979 teaches a
spring-coupled ferrule which urges the ferrule holder in a
direction axially toward the mated fiber. However, these are free
standing optical elements, without consideration of the design
requirements of simultaneous electrical connections, and therefore
combination with known hybrid designs is non-trivial. These
floating device elements neither teaches nor suggests combining a
floating optical element into a hybrid electrical/optical connector
that simultaneously optimizes both electrical and optical mating in
the presence of the floating elements, a non-trivial manufacturing
step.
[0015] Each of the above connector systems and methods suffer from
one or more limitations noted above, in that they do they do not
incorporate Z-tolerance into both optical and electrical connecting
elements (e.g., do not incorporate improved axial tolerance at all,
or are not combined into a single, integrated connector that
simultaneously optimizes the mating requirements of both the
optical and electrical connections), which makes manufacturing and
assembly of a hybrid connector technically difficult or
expensive.
[0016] None of the above systems suggest or teach efficiently
combining optical and electrical contacts into a single hybrid
connector device optimized for both electrical and optical
connections with both (a) a Z-tolerant coupling for the optical
elements, and (b) a Z-tolerant coupling for an axial electrical
array, together resulting in a low-cost of manufacture, ease of
assembly, and single connector ease-of-use. A hybrid electrical and
optical shaft and socket connector incorporating a Z-tolerant axial
electrical array integrated with a Z-tolerant floating or
lens-coupled fiber array has not been taught or suggested, nor to
our knowledge has such a tool been previously successfully
manufactured and commercialized.
SUMMARY AND OBJECTS OF THE INVENTION
[0017] The present invention relies upon the knowledge of design
considerations needed to achieve a hybrid plug and socket connector
with a Z-tolerant central floating optical fiber coupler and a
Z-tolerant axial circumferential electrical contact array, allowing
for rapid, inexpensive, axial-position-tolerant, self-wiping,
reliable connections between connector elements, so as to provide
an improved connection. The benefits include rapid connection,
rapid disconnection, low-cost, disposability, reproducibility, and
reliability. This allows the implementation of medical monitors and
probes more simply and inexpensively than has been achieved using
commercially available connectors.
[0018] A salient feature of the present invention is that, while
both electrical and optical connectors have different
positional-accuracy mating requirements, the use of a Z-tolerant,
axially deployed, wide contact, peripheral electrical contact array
and a Z-tolerant floating central fiber core allows the differing
mating requirements to be reliably and simultaneously satisfied.
The floating optical core fiber is self-aligning, self-centering,
axially-position-tolerant, and highly stable and reproducible. The
floating component takes up Z-axis positional inaccuracies while
maintaining absolute control over the distance between the coupled
fiber faces. More than one fiber can be used. At the same time, the
linear electrical array allows broad, self-wiping, non-shorting,
physical contact areas which are themselves Z-tolerant, without the
high-mating-requirements typically demanded by optical matings.
This substantially lowers the cost of the electrical connectors,
while maintaining expandability of 1 to N non-shorting
quick-connect contacts. Further, such wide contacts can be molded
or provided by a flexible PC board very inexpensively, making the
entire connector, and in particular the plug portion,
manufacturable at very low cost.
[0019] Accordingly, an object of the present invention is to
provide a Z-tolerant hybrid connector using a wide electrical
contact array peripherally and circumferentially deployed around a
central fiber core, which is itself Z-tolerant due to lens or float
coupling. In its simplest from, the fiber core has only one fiber
coupled using an axial floating coupler, and at least two wide
peripheral electrical contacts, but this may be expanded to add
additional optical fibers and electrical contacts as needed.
Similarly, some of the electrical contacts may be replaced or
supplemented by non-contact ID chips that do not require a direct
connection.
[0020] Another object to provide a non-shorting electrical contact
array with good physical contact that is engaged and wiped by
rotation of the plug after insertion into the socket, enabling use
with sensitive electronics or high-power applications.
[0021] Another object is to provide for a high-precision
stabilization of the optical connections, which are stabilized by a
locking action with rotation of the plug shaft.
[0022] Another object is to provide for a reversible
quick-connection, with connection occurring in less than 1 full
turn of a plug shaft, and preferably latching in one-fourth
clockwise turn. This in turn allows for natural quick attachment
and for quick disconnection, with disconnection occurring again in
less than 1 full turn of the shaft, and preferably in one-fourth
counterclockwise turn.
[0023] Another object is to provide for probes and systems with
integrated connector systems, allowing for improved medical
spectroscopic devices.
[0024] A final object is to provide for a connector with embedded
identification and data, such as probe type, for example via EEPROM
accessible across the connectors electrical connections, or even by
non-contact ID functions, such as the RF chips used in proximity ID
tags.
[0025] The improved hybrid connector as described has multiple
advantages.
[0026] One advantage is that devices with both electrical and
optical connections can be quickly attached using a single
connector.
[0027] Another advantage is that a centered fiber with coupling
ferrule or coupling channel is self-aligning, and allows
incorporation of Z-tolerant optical coupling techniques, such as
transfer or collimating lenses and elements, floating couplers, and
the like.
[0028] Another advantage is that this attachment can occur
reversibly, rapidly, and reliably.
[0029] Another advantage is that the costly parts (the precision,
floating alignment tube into which a shaft ferrule fits or a
reverse collimating lens) can be placed into the socket connector,
while the male plug shaft has only printed-circuit or card edge
contacts, and low-tolerance optical ferrules, which are inexpensive
compared to individual electrical contacts and precision optical
connectors.
[0030] A further advantage is that the electrical connection can be
expanded as to any number of contacts, simply by increasing the
length of the inserted shaft, reducing the spacing of the contacts,
or adding additional parallel electrical array contact rows.
[0031] There is provided a Z-tolerant hybrid connector for
providing a reliable, rapid, unified, and reversible connection for
mixed electrical and optical connections, specifically in the
examples shown for the purpose of enabling spectroscopic analysis
in human patients in real time. In one example, the Z-tolerant
connector uses an axial plug with a semi-circumferential-element
linear electrical contact array deployed axially along its long
axis, with central fiber and optical connection elements. A
floating axial positionally tolerant floating coupler allows the
fiber coupling to maintain a high internal axial accuracy with an
inexpensive low axial-accuracy plug shaft. The plug mates
reversibly to a socket containing a keyed channel into which the
plug's shaft is fully inserted and then rotated. A turn of the plug
shaft mates the electrical pads on the plug shaft with the spring
contacts in the hollow channel of the socket, as well as
stabilizing and securing the plug. Removal is achieved by rotation
in the opposite direction, breaking the electrical contacts and
allowing the plug to be removed from the hollow channel. Medical
probes and systems incorporating the improved connector are also
described.
[0032] These and other advantages of the invention will become
apparent when viewed in light of the accompanying drawings,
examples, and detailed description. The breadth of uses and
advantages of the present invention are best understood by the
detailed explanation of the workings of a hybrid connector, now
constructed and tested in laboratory and clinical medical
monitors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The invention will be more clearly understood from the
following description in connection with the accompanying drawings
of which:
[0034] FIG. 1A is an exploded perspective view of a plug and socket
in accordance with the present invention;
[0035] FIG. 1B is an enlarged view of the spring loaded contacts in
the socket of FIG. 1A;
[0036] FIG. 2 is a perspective view of the plug;
[0037] FIG. 3A is a perspective view partly in section showing the
plug as it is inserted and seated into the socket;
[0038] FIG. 3B is an enlarged view of a portion of the inserted
plug and socket of FIG. 3A;
[0039] FIG. 4 is a front view of the plug;
[0040] FIG. 5 is a side view of the plug showing the guiding and
locking channel;
[0041] FIG. 6 is a plan view of the socket;
[0042] FIG. 7 is a rear view of the socket;
[0043] FIG. 8 is a plan view of the socket showing the contact
pins;
[0044] FIGS. 9A and 9B are sectional perspective views illustrating
insertion and rotation of the plug;
[0045] FIG. 10 is a sectional view showing the plug inserted into
the socket;
[0046] FIG. 11 shows a medical probe incorporating the Z-tolerant
hybrid connector of FIGS. 1-10;
[0047] FIG. 12 shows a medical monitor incorporating the Z-tolerant
hybrid connector of FIGS. 1-10 to which the probe of FIG. 11 is
attached to form a complete medical system;
[0048] FIG. 13A is a graph showing a plateau of Z-tolerant
connections the ability using a floating optical connection
designed in accordance with the present invention;
[0049] FIG. 13B is a graph showing a plateau of Z-tolerant
connections the ability using a coupling lens element designed in
accordance with the invention.
DEFINITIONS
[0050] For the purposes of this invention, the following
definitions are provided:
[0051] Hybrid Connector. A connector that contain both optical and
electrical transmission lines to be coupled. Also called a Mixed
Connector.
[0052] Plug: The elongated, shaft-like member of the connector.
Also called a Male Plug or Shaft.
[0053] Socket: The hollow, receiving-chamber member of the
connector, to which the Plug member is coupled by insertion of the
plug into the receptacle. Also called a Female Socket, Receptacle,
or Chamber.
[0054] Peripheral: Located on or near the outer surface of the plug
shaft, or the along the inner chamber surface of the socket
receptacle. Examples of peripheral contacts include an array of
electrical pad elements located on the surface of a rod-shaped
plug, or a card edge located near the surface of a rod-shaped plug
(c.f. central).
[0055] Central: Located at the inner or central region, not
peripherally. For the shaft of a plug, the core is toward the
center of the shaft; for a socket, the core is located toward the
axial central portion of the space in the socket chamber (c.f.
peripheral).
[0056] Axial: Along the long axis of an elongated member or
connector insertion path. Also called the Z-Axis (c.f.,
planar).
[0057] Planar: Located perpendicular to the long axis of an
elongated member or connector insertion path.
[0058] Z-Tolerant or Axially Position-Tolerant: An element for
which proper operation or coupling is not highly dependent upon an
exact position of the inserted plug relative to receptacle socket
in the axial (Z-axis) direction.
[0059] Axial Array: A set of at least two contact elements deployed
axially, for example a linear row of electrical contact pads are
each deployed circumferentially at different fixed distances along
the length of the shaft of a plug (c.f., planar array, below).
[0060] Planar or X-Y Array: A set of at least two contact elements
deployed in a plane perpendicular to the insertable plug face.
[0061] Circumferential: Following the circumferential curve of a
rod, shaft, or chamber, while keeping, more or less, the same
linear distance from the end of the rod, shaft, or chamber. A
circumferential element may be a circular ring (fully
circumferential), or an open ring or short arc
(semi-circumferential). A semi-circumferential ring, pad, or arc
shaped element only partially encircles the rod, shaft, or
chamber.
[0062] Rotationally Engaged: A connector that is rotated in order
to lock the probe and/or engage one or more sets of contacts.
[0063] Optical Coupling: The arrangement of two optical elements
such that light exiting the first element interacts, at least in
part, with the second optical element. This may be free-space
(unaided) transmission through air or space, or may require use of
intervening, fixed or floating, optical elements such as lenses,
filters, fused fiber expanders, collimators, concentrators,
collectors, optical fibers, prisms, mirrors, or mirrored
surfaces.
[0064] Electrical Coupling: The arrangement of two electrical
elements such that the two elements can electrically interact and,
in most cases, useable current can flow between them.
[0065] Floating Coupler: A Z-tolerant optical coupling element. In
one example, the Z-tolerant optical coupling element is a
spring-loaded floating coupler that physically moves axially to
allow for a high-precision coupling of two or more optical fibers,
while allowing for tolerance of significant variance in the axial
position of one fiber to the other, thus enabling a quality optical
coupling that is tolerant of axial positional error without the
risk of poor optical coupling due to excessive fiber face to fiber
face distance, or of damaging the coupled fiber faces due to
insufficient fiber face to fiber face distance. In another example,
the Z-tolerant optical element is a set of collimating lenses that
have a relative insensitivity to the distance between the lens
elements, allowing for Z-tolerance in the distance between the
coupled fibers to be of low importance to the quality of the
optical connection.
DESCRIPTION OF A PREFERRED EMBODIMENT
[0066] Referring to FIG. 1A, the connector includes a male plug 11
having an axial shaft 13 and is shown disengaged from female socket
assembly 14. The shaft 13 contains an axial central optical fiber
which terminates in a ferrule 16. The shaft may accommodate
multiple optical fibers. The ferrule 16 is just one example of an
optical coupling element, and other equivalent elements would work
provided they result in optical coupling across the connector. In
FIG. 1A, a circuit board 17 is shown detached from the socket. The
circuit board includes a plurality of spring loaded contact
elements 18 shown in enlarged view in FIG. 1B which project into
the socket through the slot 21 shown in dotted line. It is apparent
that the contact elements may form a part of the socket.
[0067] FIG. 2 is a perspective view of the male plug 11 rotated to
show a plurality of electrical contacts 22 which extend from the
flat surface 23 onto rounded portion of the shaft for electrical
contact with the contact elements 18. The number of contacts depend
upon the electrical requirements of the electro-optical device with
which the plug is associated. The electrical contacts 22 may be
plated copper pads on a flexible circuit board that is adhered to
the shaft. The contacts are mounted along flat portion 23 of the
shaft and extend onto the rounded portion of the shaft. The
contacts have axially extending leads 25. Such use of flexible
printed circuit contacts facilitates the rapid mass production
after injection molding of the plug or shaft and further allows
direct connection to integrated circuits which may be embedded in
the connector such as an EEPROM memory 24.
[0068] Referring to FIGS. 1A, 1B, 3A, 3B and 5, the shaft has an
L-shaped alignment channel 26 diametrically opposite the flat
surface 23 of the plug. The socket includes a pin 28, FIG. 1A and
FIG. 3A, which engages the alignment channel as the shaft is
inserted into the socket as illustrated in FIG. 3A. The axial
movement of the shaft is stopped when the pin engages the
circumferential or arm portion 29 of the groove. The shaft is then
rotated so that the pin travels into the perpendicular extending
portion of the groove 29 until it is fully engaged. As the shaft is
inserted, the contact elements 22 on the flat portion of the shaft
do not engage the spring loaded contacts 18. After the shaft is
inserted and rotated, the portion of the contacts extending onto
the rounded portion are brought into sliding engagement with the
contact elements to provide a sliding contact. Thus the electrical
connection portion of the connector has been described.
[0069] Turning now to FIGS. 6-10 the optical coupling portion of
the connector is described. The socket 14 includes a bore 31 which
is enlarged 32 at its distal end to terminate in shoulder 33. The
enlarged bore receives a floating spring loaded optical coupling
element 34 which has a portion of reduced diameter 35 to receive a
spring 36. An end plate 37 is secured to the end of the socket by,
for example screws 35, and engages the other end of the spring 36
to urge the coupling element in the axial direction so that it
abuts the shoulder 33. Optical cable such as cable 38 with optical
fibers, such as fiber 39 extends into the coupling element a
predetermined distance. The end of the cable may be polished to
present the optical fiber at its face 40. When the plug is inserted
into the socket the coupling element receives the ferrule at the
end of the plug and centers and guides the ferrule until the
shoulder 41 at the end of the plug engages the end of the coupling
element. At this point the end face of the ferrule 16 and the face
of the optical cable are accurately spaced and positioned with
respect to one another for good optical coupling without physical
contact. The plug can then be rotated for providing the sliding
electrical contact described above.
[0070] Thus the coupling element is adapted to receive the ferrule
when the plug is inserted into the socket and the distance between
the end of the ferrule fibers and the end of the coupler fibers are
closely spaced to one another to provide the optical coupling. As a
result there is one-to-one alignment of the optical fibers as the
electrical contact is made and the plug is inserted into the
socket.
[0071] Connector plug 13 can optionally be embedded within a
medical device, as shown with plug 13 embedded in medical catheter
probe 203 (FIG. 11). Probe 203 has patient-end 206, catheter body
207, and monitor-end 208. In probe 203, flexible body 207 consists
of a section of US FDA class VI heat shrinkable tubing 214
surrounding medical grade Tygon.TM. tubing 217, both of which are
further swaged to light illuminator 218 at swage points 219 near
probe patient end 206. Wires 222 and 223, from electrical contacts
22 of plug 13 (as shown in FIGS. 3A, 3B) travel through concentric
tube 214 and 217 and terminate by connecting to the leads 25 of
plug 13 at monitor end 208. Optical connection fiber 224 from
illuminator 218 travels from the patient tip of probe 203, running
parallel with wires 223 and 224 inside concentric tubes 214 and
217, to terminate in ferrule 16 of monitor-end plug 13. Plug 13 is
a reversible hybrid connector plug containing the electrical and
optical connections described above.
[0072] Probe 203 may be "smart" with optional memory chip 24
integrated into probe body 13. This chip may retains information
useful in the operation of the device, such as calibration
parameters, a reference database, a library of characteristic
discriminant features from previously identified tissues, and so
on, and this information may be accessible via plug 13.
Additionally, information on chip 24 may include probe
identification, probe serial number, use history, calibration
details, or other information accessible through plug 13.
[0073] The hybrid connector 11 may be incorporated into a medical
system, such as medical system 267, FIG. 12 with probe attached to
system 267 via plug 13 and socket 14. Examples of such a
spectroscopic monitoring system and monitoring probe are disclosed
in WO 03/086173.
[0074] Operation and use of the connector is now described. In this
example, connector plug 13 is incorporated into medical catheter
probe 203, and connected to spectroscopic monitoring device 267 via
socket 14, as shown in FIG. 12.
[0075] Referring again to FIGS. 3A, 3B, Plug 13 is first inserted
into socket 14. To accomplish this, the plug 13 is held in axial
alignment with the socket 14. Probe shaft 13 is then inserted into
socket 14 after aligning pin 28 of socket 14 mates with slot 26 of
plug 13. This movement is illustrated by axial insertion/removal
arrows 42. Connector plug 13, and ferrule 16 are pushed with zero
to low insertion force until they are fully inserted.
[0076] A key step now occurs. Ferrule 16 of plug 13 is
automatically aligned as, and it mates with coupler 33 a few
millimeters before ferrule 16 is fully inserted. The faces of the
optical fiber to be coupled would likely be either damaged due to
contact collision, or the faces would be too far separated to be
efficiently coupled. However, in this embodiment, coupler 33 is a
floating connector, held as forward as allowed in the design toward
the insertion (entry) end of socket 14 by spring 36. As ferrule 16
reaches full insertion in coupler 33, the fiber faces are allowed
to continue to remain within microns of each other, without
collision, and while ferrule 16 is fully inserted into, coupler 33.
The coupler moves to absorb the further and final forward movement
of ferrule 16. This movement allows pin 28 of socket 14 to be fully
inserted along slot 29 of plug 13, bringing ferrule 16 into
effective optical contact. The electrical contacts 22 are now in
axial but not rotational alignment with socket electrical contact
array 22. Thus, contact array 22 and socket array 18 remain out of
electrical contact at this time.
[0077] Finally, plug 13 is rotated 1/4 turn clockwise in socket 14,
a movement not permitted during the initial axial insertion into
socket 14 because the channel 26 permits only axial in-out
movement. However, once plug 13 is fully inserted into socket 14,
rotation is permitted because pin 28 can now turn into
partially-circumferential short arm 29 of channel 26, as shown in
FIG. 3. Once pin 28 has rotated to the distal end of short-arm 29,
plug 13 is fully rotated and cannot rotate further in the same
direction. The rotation of plug 13 after axial insertion performs
at least three functions. First, pin 28 is now in the distal
portion of short arm 29 of channel 26, securing and locking plug 13
in place and preventing axial displacement or removal of plug 13
from socket 14. Second, ferrule 16 is held with pressure in
continued optical alignment in connector 33, maintaining proper
optical fiber alignment and spacing despite probe movement in, then
slightly out, in the Z-axis axial direction. Third, contact array
22 is held in sustained electrical contact with socket array
18.
[0078] Some probes may also require an illumination fiber, or other
additional fiber channels, without critical alignment requirements.
Such can use other optical ferrules added to the probe. In some
cases, these additional fibers may not be as alignment
critical.
[0079] In some cases, memory chip 24 can be added to the connector,
or memory-read circuitry can be added to the socket as well, or
vice-versa.
[0080] Last, additional non-contact connections can broaden
utility. For example, a "passive" radio-frequency identifier chip
can perform the handshaking function with an internal memory chip,
allowing a circuit in the female side to query and read a chip on
the male side. Similar effects can be accomplished with an active
transmitter on the male side, using known wireless linking
technologies known in the art. In fact, the power for the
illuminator could even be transmitted, as non-contact power
transmission technologies are now also known.
EXAMPLES
[0081] Operation of the device is demonstrated in the following
examples, constructed using a shaft and socket connection
constructed in accordance with the present invention.
Example 1
[0082] A working version of the optical and electrical hybrid
connector was constructed. Light throughput was recorded in using
an EXFO optical power meter (Exfo, Quebec, Canada) through 100
micron glass/glass optical fiber (FV100/101/125 silica clad fiber,
Polymicro Technologies, Phoenix Ariz.) as the shaft plug is
inserted in the receptacle socket. Axial displacement relative to
the final, fully inserted position was recorded at intervals of 1
mm over the final 1 cm of insertion. Referring now to FIG. 13A, the
recorded optical power values were plotted as line 312, which is a
function of relative optical throughput vs. distance from the fully
inserted connector position. There is noted plateau region 317
spanning the final 2 mm of insertion, in which the intensity of
transmitted light does not fall by more than 12%, demonstrating (by
definition) an axial-position tolerance.
[0083] The above experiment was then repeated using the same shaft
and socket system, but in this case with optical coupler 33 and
spring element 36 secured such that the floating action was
completely ablated. Referring again to FIG. 13A, the recorded
optical power values were plotted as line 319. There is no stable
plateau region in transmitted intensity line 319 with shaft axial
position--even a 1 mm displacement results in 50% signal
loss--showing that without the floating element, Z-tolerance is
lost.
[0084] The relevance of the above experiment is that the
manufacturing of a metal or plastic shaft with millimeter tolerance
(i.e., .+-.1 mm), the axial tolerance is well handled by the
Z-tolerant floating connector design. In contrast, the non-floating
system does not exhibit Z-tolerance, and therefore requires micron
manufacturing tolerances (e.g., 0.02 mm, or .+-.20 microns). The
high precision required in the non-Z-tolerant connector
necessitates significantly more precise and costly stainless steel
molds and/or laser drilled components. In our experience with
reducing the above design to manufacturability, a Z-tolerant shaft
plug can be produced for about one-fifth the cost of the
non-tolerant shaft in similar volumes.
Example 2
[0085] An optical and electrical hybrid connector was constructed
where optical coupler was an SMA optical coupler/connector with
integrated reversed beam expander optics (Model F230SMA-A
collimator, Thorlabs, Newton, N.J.), and further, spring 36 was
omitted such that the physical floating action of coupler 33 was
completely eliminated. The design, however, remains Z-tolerant, as
the collimating lens provides lens-coupled
axial-position-tolerance.
[0086] As before, light throughput was recorded using an optical
power meter through 100 micron glass/glass optical fiber as the
probe was inserted into the connector. Axial displacement from the
final, fully inserted position was recorded at intervals of 1 mm
over the final 1 cm of insertion. Referring now to FIG. 13B, the
recorded optical power values were plotted as line 322, which is a
function of relative optical throughput vs. distance from the fully
inserted connector position. There is noted plateau region 327
spanning the final 5 mm of insertion, in which the intensity of
transmitted light does not fall by more than 20%, demonstrating (by
definition) an axial-position tolerance. In this case, the
Z-tolerance comes not from a floating element as in Example 1, but
rather from the lens-coupled collimator that increases the
Z-tolerance of the optical coupling.
[0087] The above experiment was then repeated using the same shaft
and socket system, but in this case with the non-floating optical
coupler from Example 1, above, in place of lens-coupled optical
coupler of the above paragraph. This is identical to the setup of
the non-Z-tolerant experimental set up of Example 1. Referring
again to FIG. 13 there is no plateau region in transmitted
intensity line 329 with changes in shaft axial position, showing
that without the lens-coupled element, Z-tolerance once again no
longer exists.
[0088] Other methods of hybrid connection Z-tolerance may be
envisioned, including the combination of lens- and float-coupled
optical elements, or alternative methods readily apparent to one
skilled in the art. The examples of lens- and float-coupled
elements are provided merely as examples, and are not intended to
be limiting with respect to the present invention.
[0089] In summary, an improved hybrid connector can result from an
axial position-tolerant hybrid connector with a central fiber set,
peripheral axial electrical connector array, and a Z-tolerant
optical and electrical connection. In certain applications, such as
medical applications, this allows for single-connector,
quick-connect, quick-disconnect, self-aligning, low-insertion-force
probes with an on-board memory chip identifying the probe. Such
improved connectors permit hybrid connections to be easily added
into a medical probe, catheter, or monitor system.
[0090] We have discovered an improved Z-tolerant hybrid optical and
electrical connector for making reversible, for single-connector,
quick-connect, quick-disconnect, self-aligning, hybrid connections.
Such a connector has been constructed and tested, and incorporated
into a medical catheter, all constructed in accordance with the
present invention to a functional hybrid connector. An EEPROM
within the shaft allows for tracking, identification, and
calibration of the probe. Medical probes and systems incorporating
the improved illuminator, and medical methods of use, are
described. This device has been built and tested in several
configurations, and has immediate application to several important
problems, both medical and industrial, and thus constitutes an
important advance in the art.
* * * * *