Abstract:
An interconnection between a sensor and a monitor has a cable, an information element and a switch. The cable has conductors providing electrical communication between a sensor connector and a monitor connector. The information element is readable by the monitor and mounted in the sensor connector, the monitor connector or the cable. A switch is mounted in the sensor connector and is responsive to the sensor connecting to and disconnecting from the sensor connector so as to alter the readability of said information element.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application relates to and claims the benefit of prior U.S. Provisional Application No. 60/546,531 entitled Connector Switch, filed Feb. 20, 2004 and incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Pulse oximetry is a widely accepted noninvasive procedure for measuring arterial oxygen saturation, which provides early detection of hypoxia.  FIG. 1  illustrates a pulse oximetry system  100  having a sensor  110  applied to a patient, a monitor  120 , and a patient cable  130  connecting the sensor  110  and the monitor  120 . The sensor  110  has emitters and a detector, which are attached to a tissue site, such as a finger as shown. The patient cable  130  transmits an emitter drive signal from the monitor  120  to the sensor  110  and a resulting detector signal from the sensor  110  to the monitor  120 . The monitor  120  processes the detector signal to provide a numerical readout of oxygen saturation and pulse rate.  
         [0003]     FIGS.  2 A-B illustrate a pulse oximetry sensor  110 . As shown in  FIG. 2A , the sensor  110  has an adhesive wrap  205  that positions emitters  250  (not visible) proximate, for example, a finger nail and a detector  260  (not visible) proximate a finger pad. A sensor plug  200  inserts into a sensor connector  135  ( FIG. 1 ) so that plug contacts  201  are in electrical communications with the monitor  120  ( FIG. 1 ) via the patient cable  130  ( FIG. 1 ).  
         [0004]     As shown in  FIG. 2B , a pulse oximetry sensor  110  has both red and infrared light emitting diode (LED) emitters  210 ,  220  and a photodiode detector  230 . LED pinouts  250  on the plug contacts  201  ( FIG. 2A ) connect the LEDs  210 ,  220  to the monitor  120  ( FIG. 1 ). Detector pinouts  260  on the plug contacts  201  ( FIG. 2A ) connect the photodiode  230  to the monitor  120  ( FIG. 1 ). The sensor  110  may also have an information element  240 , such as a resistor. The information element  240  may have various uses, such as an indicator of sensor type, depending on the manufacturer. A pulse oximetry sensor is described in U.S. Pat. No. 6,256,523 entitled Low Noise Optical Probes; a pulse oximetry monitor is described in U.S. Pat. No. 6,826,419 entitled Signal Processing Apparatus And Method; and an information element is described in U.S. Pat. No. 5,758,644 entitled Manual and Automatic Probe Calibration, all of which are assigned to Masimo Corporation, Irvine, Calif. and incorporated by reference herein.  
       SUMMARY OF THE INVENTION  
       [0005]     A patient cable can be an adapter cable. That is, it can function to physically and electrically adapt a sensor to an otherwise incompatible monitor. For example, some monitors are configured to read a sensor information element. An adapter cable for a sensor that does not have an information element can incorporate that element in the adapter cable itself, such as within one of the adapter cable connectors. In some circumstances, however, removing the sensor from such an adapter cable can result in a monitor status message indicating a malfunctioning sensor rather than a disconnected sensor. This arises because the monitor is able to read the information element but is unable to receive a detector signal. A connector switch, however, advantageously electrically disconnects the information element from the monitor when the sensor is disconnected from the adapter cable. In that manner, the monitor will detect the absence of both a sensor and an information element and display a correct status message accordingly.  
         [0006]     One aspect of a connector switch is an interconnection between a sensor and a monitor having a cable, an information element and a switch. The cable has conductors providing electrical communication between a sensor connector and a monitor connector. The information element is readable by the monitor and mounted in the sensor connector, the monitor connector or the cable. A switch is mounted in the sensor connector and is responsive to the sensor connecting to and disconnecting from the sensor connector so as to alter the readability of said information element.  
         [0007]     Another aspect of a connector switch is an interconnection method that provides a cable configured to communicate drive signals from a physiological parameter monitor to a sensor and physiological signals from the sensor to the monitor. An information element is associated with the cable, where the information element is capable of conveying information regarding the sensor to the monitor. A switch is actuated in response to the sensor connecting and disconnecting to the cable so as to render the information element readable and unreadable by the monitor, respectively.  
         [0008]     A further aspect of a connector switch is a sensor-monitor interconnection comprising a cable adapted to communicate signals between a physiological sensor and a physiological parameter monitor. An information element is capable of conveying information regarding the sensor to the monitor. A switch is associated with the cable and responsive to the physiological sensor connecting to and disconnecting from the cable so as to enable and disable the reading of the information element by the monitor. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a perspective view of a pulse oximetry system;  
         [0010]     FIGS.  2 A-B are a top view and a schematic diagram of a pulse oximetry sensor;  
         [0011]      FIG. 3  is a perspective view of a patient cable;  
         [0012]      FIG. 4  is a schematic diagram of a patient cable having a connector switch;  
         [0013]     FIGS.  5 A-B are side views of unattached and attached sensor and patient cable connectors;  
         [0014]     FIGS.  6 A-B are exploded bottom and top perspective views of a sensor connector;  
         [0015]     FIGS.  7 A-C are bottom and side views of a spring assembly and a bottom view of a partial top shell assembly;  
         [0016]     FIGS.  8 A-B are bottom views of a printed circuit board (PCB) and a top shell assembly;  
         [0017]     FIGS.  9 A-C are exploded side, assembled side and assembled front views of a sensor connector;  
         [0018]      FIG. 10  is a top view of a PCB;  
         [0019]     FIGS.  11 A-D are exploded perspective, top, front and side views of a PCB assembly;  
         [0020]     FIGS.  12 A-C are top, side, and detailed top views of a wired PCB assembly;  
         [0021]     FIGS.  13 A-C are bottom, side and top views of a taped PCB assembly;  
         [0022]     FIGS.  14 A-C are top, front, and side views of a shielded PCB assembly;  
         [0023]     FIGS.  15 A-D are unfolded top, top, front, and side views of a connector spring; and  
         [0024]      FIG. 16  is a side view of a spring and latch assembly. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]      FIGS. 3-4  illustrate an adapter patient cable  300  having a sensor connector  310  and a monitor connector  320  physically and electrically connected by a cable  330 . The sensor connector  310  has a resistor  410  ( FIG. 4 ) and a normally open (N.O.) switch  420  ( FIG. 4 ) in series with the resistor  410 . The resistor  410  functions as a sensor information element, as described above. The switch  420  is responsive to a sensor being attached or removed from the sensor connector  310 , as described below. Utilizing the switch  420  to connect and disconnect the resistor advantageously allows a connected monitor to indicate accurate status information regarding a sensor.  
         [0026]     In particular, when a sensor is attached to the sensor connector  310 , the switch  420  moves to a closed position  522  ( FIG. 5B ) connecting the resistor  410  to the monitor so that the monitor is able to read the resistor  410 . When a sensor is removed from the sensor connector  310 , the switch  420  returns to an open position  521  ( FIG. 5A ) disconnecting the resistor  410  from the monitor so that the monitor is unable to read the resistor  410 . As such, the monitor is able to unambiguously detect when a sensor is attached or removed from the sensor connector  310  and, accordingly, the monitor indicates a removed sensor rather than a malfunctioning sensor.  
         [0027]     FIGS.  5 A-B illustrate the mechanical details of inserting and removing a sensor plug  200  into the sensor connector  310 . In particular, when the plug  200  is inserted, plug contacts  201  electrically connect with the sensor connector contacts  1030 , and the tab  203  presses the switch  420  to a closed position  522 . When the plug  200  is removed, the tab  203  releases the switch  420 , which returns to its normally open position  521 .  
         [0028]     FIGS.  6 A-B illustrate a sensor connector  310  having a cable assembly  610 , a spring assembly  620 , a top shell  630  and a bottom shell  640 . Construction of the sensor connector  310  is illustrated in detail with respect to  FIGS. 7-9 . Construction of the cable assembly  610  is illustrated in detail with respect to  FIGS. 10-14 . Construction of the spring assembly  620  is illustrated in detail with respect to  FIGS. 15-16 .  
         [0000]     Sensor Connector Construction  
         [0029]     FIGS.  9 A-C illustrate a sensor connector  310  having a top shell assembly  700  and a bottom shell  640 . FIGS.  8 A-B illustrate the top shell assembly  700  having a cable assembly  610 , a spring assembly  620  and a top shell  630 . FIGS.  7 A-B illustrate the spring assembly  620  including a spring  1500 , a latch  1620  and buttons  1610  so as to secure and release the tab  203  (FIGS.  5 A-B) of a sensor plug  200  (FIGS.  5 A-B).  FIG. 7C  shows the spring assembly  620  is inserted into the top shell  630  As shown in FIGS.  8 A-B, the cable assembly  610  is inserted into the top shell  630  over the spring assembly  620 . As shown in FIGS.  9 A-C, the top shell assembly  700  is attached to the bottom shell  640 . In one embodiment, the bottom shell  640  is ultrasonically welded to the top shell assembly  700 . As shown in FIGS.  9 B-C, the assembled sensor connector  310  has a front portion  910  and a back portion  920 . The front portion  910  has a socket  912  configured to removably accept a sensor plug  200  (FIGS.  5 A-B). The back portion  920  is fixedly attached to a patient cable  330  ( FIG. 3 ) electrically connecting the sensor to a monitor. Both sides of the sensor connector  310  have buttons  1610  adapted to release the sensor when pressed.  
         [0000]     Cable Assembly Construction  
         [0030]     FIGS.  14 A-B illustrate a cable assembly  610  having a printed circuit board (PCB) assembly  1100  (FIGS.  11 A-D), an attached cable  1210  (FIGS.  12 A-C) and tape  1310  (FIGS.  13 A-B). As shown in  FIGS. 11 , the PCB assembly  1100  has a PCB  1000 , a bushing  1120  and contacts  1130 , a component side  1001  adapted to attach components and a plug side  1002  configured to accept a sensor plug  200  (FIGS.  5 A-B). As shown in  FIGS. 10-11A , the PCB  1000  has a bushing aperture  1012 , end slots  1014 , contact slots  1016 , and pads  1019 . The aperture  1012  is generally disposed off center of the PCB  1000  so as to accommodate the bushing  1120 . The slots  1014 ,  1016  are disposed on one side of the aperture  1012  and adapted to receive the contacts  1130 . The pads  1019  are distributed on the other side of the aperture  1012  and configured for a solder connection of cable wires.  
         [0031]     As shown in FIGS.  11 A-D, the bushing  1120  is generally cylindrical having a wide portion  1124  and a narrow portion  1126 . The wide portion  1124  accommodates a removable latch  1620  (FIGS.  16 A-B) that is configured to secure and release a sensor plug tab  203  ( FIG. 2A ). The narrow portion  1126  is configured to fasten the bushing  1120  to the PCB  1000 . In particular, the bushing  1120  is inserted into the PCB  1000  on the component side  1101  so that the wide portion  1124  is seated flush with the PCB  1000  surface and the narrow portion  1126  fits inside the aperture  1012 .  
         [0032]     Also shown in FIGS.  11 A-D, the contacts  1130  have first ends  1132  and second ends  1134  and extend through the contact slots  1016  ( FIG. 10 ) from the component side  1101  to the plug side  1102 . The first ends  1132  are soldered into mounting holes  1118 . A switch  420  mounted on the plug side  1102  has a mounted end  1142  soldered to the PCB assembly  1100  and a contact end  1144  movable between an open position  521  ( FIG. 5A ) and a closed position  522  ( FIG. 5B ), as described above.  
         [0033]     FIGS.  12 A-C illustrate a wired PCB assembly  1200  having a PCB assembly  1100 , an attached cable  1210 , a resistor  410  and cords  1230 . Wires  1212  extend from the end of the cable  1210  and are soldered to corresponding pads  1019 . Cords  1230  are wrapped around and glued to the bushing  1120 . The resistor  410 , described above, is attached on the component side  1101 .  
         [0034]     FIGS.  13 A-B illustrate a taped PCB assembly  1300  having a wired PCB assembly  1200  and a tape  1310  which covers the soldered ends  1132  ( FIG. 11A ) of the contacts  1130  along the mounting pads  1118 . The tape  1310  has a first portion  1312  attached over the plug side  1102  and a second portion  1314  attached over the component side  1101 . In one embodiment, the tape is kapton.  
         [0035]     FIGS.  14 A-C illustrate a cable assembly  610  having a taped PCB assembly  1300  and an EMI shield  1410 . The EMI shield  1410  has an aperture  1412  that accommodates the bushing  1120  and snaps into a bushing groove  1122 .  
         [0000]     Spring Assembly Construction  
         [0036]     FIGS.  15 A-D illustrate a connector spring  1500  which actuates a latch  1620  ( FIG. 10 ) to secure and release a sensor plug  200  ( FIG. 2A ). The connector spring  1500  has a spring bar  1510  and foldable sides  1520 . The spring bar  1510  extends between the sides  1520  and has a centered aperture  1512  that accommodates a latch  1620  ( FIG. 16 ). The sides  1520  have mounting holes  1522  configured to attach buttons  1610  ( FIG. 16 ). The sides  1520  are bent so as to extend generally perpendicular to the spring bar  1510 .  
         [0037]      FIG. 16  illustrates a spring assembly  1600  having a connector spring  1500 , buttons  1610  and a latch  1620 . The buttons  1610  have inserts  1612  that snap into the corresponding mounting holes  1522  so as to fasten the buttons  1610  to the connector spring  1500 . The latch  1620  has a inclined face  1622  and an opposite flat face  1624  and is secured into the connector spring  1500  so that the flat face  1624  fits into the aperture  1512  and is secured with the connector spring  1500 . The latch  1620  is adapted to fit through the bushing  1120  ( FIG. 11A ). When the buttons  1610  are pressed, the sides  1520  are compressed, flexing the spring bar  1510  so as to actuate the latch  1620 .  
         [0038]     A connector switch was described above with respect to a patient cable interconnecting a disposable finger sensor and a pulse oximetry monitor. A connector switch, however, is applicable to an interconnection between any physiological sensor for attachment to various tissue sites and any corresponding monitor for measuring various physiological parameters, such as other hemoglobin species and blood glucose to name a few. Also, a connector switch was described above in terms of a switch employing a mechanical mechanism that is physically actuated to perform an electrical connection and disconnection function. Other connector switch embodiments include a switch or switches employing, for example, electrical, electromechanical, opto-electrical or electromagnetic mechanisms, to name a few, that are physically, electrically, magnetically or optically actuated to perform an electrical connection and disconnection function. Examples include, but are not limited to, transistor, optical and proximity switches and relays among others.  
         [0039]     Further, a connector switch was described in terms of a single pole, single throw switch connecting and disconnecting a resistor between cable conductors. Other connector switch embodiments include multiple switches or multiple pole, multiple throw switches capable of selecting and deselecting or otherwise enabling and disenabling or switching between multiple information elements, including passive components, active components and various memory devices. In addition, although a connector switch was described above in terms a normally open switch, a connector switch includes a normally closed switch or switches, or a combination of normally open and normally closed switches.  
         [0040]     A connector switch has been disclosed in detail in connection with various embodiments. These embodiments are disclosed by way of examples only and are not to limit the scope of the claims that follow. One of ordinary skill in art will appreciate many variations and modifications.