Patent application title: Optical and Electrical Hybrid Connector
David A. Benaron (Portola Valley, CA, US)
Ilian H. Parachikov (Belmont, CA, US)
Michael R. Fierro (Los Gatos, CA, US)
Michael R. Fierro (Los Gatos, CA, US)
Marvin K. Hutt (Oakland, NJ, US)
IPC8 Class: AG02B638FI
Class name: With disengagable mechanical connector structure surrounding optical fiber-to-fiber connection with additional nonoptical structure
Publication date: 2008-12-11
Patent application number: 20080304793
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.
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.
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 wirestraversing a length of said catheter and electrically connected to both said light source and tocontacts 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.
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
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
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).
These limitations and requirements are best appreciated by examining the source of such differences between optical and electrical connections during mating and assembly.
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.
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.
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.
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.
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.
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.
The above limitations of conventional connectors are apparent in the art.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.
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.
Another object is to provide for probes and systems with integrated connector systems, allowing for improved medical spectroscopic devices.
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.
The improved hybrid connector as described has multiple advantages.
One advantage is that devices with both electrical and optical connections can be quickly attached using a single connector.
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.
Another advantage is that this attachment can occur reversibly, rapidly, and reliably.
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.
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.
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.
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
The invention will be more clearly understood from the following description in connection with the accompanying drawings of which:
FIG. 1A is an exploded perspective view of a plug and socket in accordance with the present invention;
FIG. 1B is an enlarged view of the spring loaded contacts in the socket of FIG. 1A;
FIG. 2 is a perspective view of the plug;
FIG. 3A is a perspective view partly in section showing the plug as it is inserted and seated into the socket;
FIG. 3B is an enlarged view of a portion of the inserted plug and socket of FIG. 3A;
FIG. 4 is a front view of the plug;
FIG. 5 is a side view of the plug showing the guiding and locking channel;
FIG. 6 is a plan view of the socket;
FIG. 7 is a rear view of the socket;
FIG. 8 is a plan view of the socket showing the contact pins;
FIGS. 9A and 9B are sectional perspective views illustrating insertion and rotation of the plug;
FIG. 10 is a sectional view showing the plug inserted into the socket;
FIG. 11 shows a medical probe incorporating the Z-tolerant hybrid connector of FIGS. 1-10;
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;
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;
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.
For the purposes of this invention, the following definitions are provided:
Hybrid Connector. A connector that contain both optical and electrical transmission lines to be coupled. Also called a Mixed Connector.
Plug: The elongated, shaft-like member of the connector. Also called a Male Plug or Shaft.
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.
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).
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).
Axial: Along the long axis of an elongated member or connector insertion path. Also called the Z-Axis (c.f., planar).
Planar: Located perpendicular to the long axis of an elongated member or connector insertion path.
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.
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).
Planar or X-Y Array: A set of at least two contact elements deployed in a plane perpendicular to the insertable plug face.
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.
Rotationally Engaged: A connector that is rotated in order to lock the probe and/or engage one or more sets of contacts.
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.
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.
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
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.
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.
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.
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.
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.
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® 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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Operation of the device is demonstrated in the following examples, constructed using a shaft and socket connection constructed in accordance with the present invention.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Patent applications by David A. Benaron, Portola Valley, CA US
Patent applications by Ilian H. Parachikov, Belmont, CA US
Patent applications by Marvin K. Hutt, Oakland, NJ US
Patent applications by Michael R. Fierro, Los Gatos, CA US
Patent applications in class With additional nonoptical structure
Patent applications in all subclasses With additional nonoptical structure