Abstract:
3 An electrical connector is disclosed which provides connection of sensors to monitors. The connector is designed to be low-profile, permit ease of attachment and disconnection, and maintain a strong connection to prevent accidental disconnects.

Description:
This application is a continuation of prior application Ser. No. 09/318,563 filed May 26, 1999, now abandoned, which is a continuation of U.S. patent application Ser. No. 08/838,392 filed Apr. 9, 1997, now U.S. Pat. No. 5,934,925, which is a continuation of U.S. patent application Ser. No. 08/543,297, filed Oct. 16, 1995, now U.S. Pat. No. 5,645,440. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to electrical connectors. More specifically, the present invention relates to the connection of medical sensors to instruments responsive to signal from the sensors. 
     2. Description of the Related Art 
     Energy is often transmitted through or reflected from a medium to determine characteristics of the medium. For example, in the medical field, instead of extracting material from a patient&#39;s body for testing, light, heat or sound may be generated and transmitted. Detection of the transmitted signal allows determination of information about the material through which the signal has passed. For example, during surgery, the body&#39;s available supply of oxygen, or the blood oxygen saturation, is monitored. Measurements such as these are often performed by measuring the ratio of incident to transmitted (or reflected) light through a portion of the body, for example a digit such as a finger, or an earlobe, or a forehead. Durable and disposable sensors are often used for such physiological measurements. These sensors have connectors which allow detachment from the instrument or cable from the instrument. 
     SUMMARY OF THE INVENTION 
     The present invention involves a connector that is configured to attach both disposable and durable sensors to instruments that are responsive to signals from the sensors or to cables from the instruments. To ensure proper operation, the connector is designed to prevent incorrect attachment of the probe to the connector. Additionally, the connector allows for easy connection and release, yet prevents accidental disconnection. Advantageously, the connector does not add significant noise to the system, and can be coated inside with RF shielding material. Additional, the connector and sensor tab are not sharp and do not contain protrusions that might hurt or scratch the patient. 
     More specifically, the present invention involves a probe connector for use in both invasive and non-invasive measurements. Examples of sensors are disclosed in FIGS. 29-56 of U.S. patent application Ser. No. 08/543,789, filed Apr. 16, 1995, now U.S. Pat. No. 5,782,757, entitled Low Noise Optical Probes, filed on the same day as the present application, which application is incorporated by reference herein. 
     The connector of the present invention couples the probe to a monitor or processor to analyze the signals from the probe. Once a sensor is inserted into the connector, the sensor is locked in place and the sensor tab (connection portion of the sensor) is shielded from electromagnetic interference. Depressing release buttons provides easy removal of the sensor from the connector. The connector has male and female portions. The female portion forms a receptacle that shields the electrical connection from fluids in the surrounding environment. 
     One aspect of the present invention involves a connector having a case defining a shroud, the case having a passageway configured to accept a sensor plug. at least one release mechanism has an engagement wedge configured such that when depressed, the engagement wedge unlocks the sensor plug from the case. An electrical connector secured within the case has contacts and is positioned such that the sensor plug, when inserted into the case, engages the contacts of the electrical connector. In one advantageous embodiment, the case further comprises a sensor plug lock, the sensor plug lock being positioned to hold the sensor plug in place when inserted into the case. Advantageously, the case further comprises a stop bar positioned to prevent insertion of the sensor plug beyond a predetermined limit. In one embodiment, the release mechanism contains at least one lift tab designed to urge the sensor plug from the sensor plug lock. In the present embodiment, the lift tab lifts the sensor plug off a locking post when the release mechanism is activated. In one embodiment, the release mechanism has at least one push tab designed to move the sensor plug in a direction out of the case when the push tab is engaged. Preferably, the electrical cable is attached to an electrical signal cable. 
     Another aspect of the present invention involves a connector having a case defining a shroud. The case has a passageway configured to accept a sensor tab. Advantageously, the case has metallic shielding. At least one release mechanism has an engagement wedge unlocks the sensor plug from the case. Preferably, the release mechanism also has spring members having metallic shielding. An electrical connector secured within the case has contacts and is positioned such that the sensor plug, when inserted into the case, engages contacts of the electrical connector. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of one preferred embodiment of the female receptacle of the connector of the present invention. 
     FIG. 2 is an exploded perspective view of the embodiment of FIG. 1 from a different angle. 
     FIG. 3 is a perspective view of one presently preferred embodiment of the connector of the present invention with the male portion disconnected from the connector and the upper portion of the connector not shown. 
     FIG. 4 is a perspective view of one presently preferred embodiment of the connector of the present invention with the male portion connected and the upper portion of the connector removed. 
     FIG. 5 is a perspective view of one presently preferred embodiment of the connector of the present invention with the male portion connected. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention involved a connector for attaching a sensor or probe to a monitor or processor so that signals from the sensor are transmitted to the processor or monitor. The connector provides easy connection and removal of the sensor to the connector while maintaining a solid connection. The connector has a low-profile design to minimize the amount of physical interference or harm by the connector in the medical environment. For instance, advantageously, the connector does not have sharp edges or protrusions that could scratch or otherwise harm the patient. 
     FIG. 5 depicts a perspective view of a connector  5  made in accordance with the present invention. As illustrated in FIG. 5, the connector  5  has a female shroud portion  7 , a male insertion portion  8 , and a cable portion  9 . Electrical connections within the connector  5  are protected from fluids and/or other disturbances by the female shroud portion  7 . Although the male insertion portion  8  is shown in FIG. 5 as a blank, in use, this male insertion portion can form a portion of the sensor (e.g., a sensor tab, sensor plug, sensor connector) or be attached to the end of a cable from a sensor. Advantageously, the cable portion  9  connects on one end to contacts within the female shroud portion  7  and on the other end to a monitor or processor. 
     FIG. 1 depicts an exploded view of the connector  5  of one preferred embodiment. The female shroud portion  7  has a bottom case  10  having a leading edge  18  and a back edge  20 . Attached to the bottom case  10  at the center of the back edge  20  is a cable mount  12 . The cable mount  12  is used to secure the cable  9  in place, as will be described further below. Although depicted in the middle of the back edge  20 , the cable mount  12  can be positioned to one side or the other in alternative embodiments. The female shroud portion  7  also has a top case  50 , discussed in further detail below. Advantageously, the female shroud portion  7  is coated inside or outside with a metallic shielding material to provide an electromagnetic shield from interference in the environment. This shields the connection from electromagnetic noise. 
     An inside face  22  of the bottom case  10  has a sensor lock  14  and a stop bar  16 . In one preferred embodiment, the bottom case also has a retaining spring  17  (only depicted in FIG.  1 ). The retaining spring  17  bears upon the top of the sensor plug  8  when the sensor plug is inserted into the connector. In addition, the retaining spring  17  provides a tactile snap when the sensor plug  8  is inserted and engages the sensor lock  14 . The operation of the sensor lock  14  and the stop bar  16  in connection with the sensor plug  8  is discussed further below. The inside face  22  of the bottom case  22  also has elevation posts  24  and positioning posts  26 . In the embodiment depicted in FIG. 1, the inside face  22  also has a support table  25  to support the sensor plug  8  when inserted. 
     Also depicted in FIG. 1 are release mechanisms  30 . The release mechanisms  30  consist of release buttons  32 , spring members  31 , lift tabs  34  and push tabs  36 . In one preferred embodiment, the spring members  31  are constructed from an etched copper and contribute to the shielding provided by the female shroud portion. In particular, the holes in the female shroud portion  7  for the release buttons  32  are shielded by the spring members  31  being metallic. Alternatively, the spring members could be made from plastic or the like and coated with a metallic shielding material. The release mechanisms  30  are designed to lift the male insertion portion  8  off the sensor lick  14  and push male insertion portion  8  away from the stop bar  16  to release the male insertion portion  8  from the connector  5 . Complete operation of the release mechanisms  30  is described below. 
     For electrical connection, an contact block  40  is provided in the connector  5 . The contact block  40  consists of multiple friction contacts  42  mounted upon a mounting frame  46 . Each contact has a connector tab  44  extending from the edge of the contact block  40  opposite from the contact extension  42 . The connector tabs  44  provide for attachment to wires from the cable  9 , which wires in turn transmit data to the processor or monitor via the cable  9 . 
     The contact block  40  is fixed in place between the top case  50  of the connector  5  and the bottom case  10 . The contact block  40  is supported on the elevation posts  24  which hold the contact block  40  just above the inside face  22  of the bottom case  10 . 
     On each side edge  52  of the top case  50  is an elongated U-shaped release button slot  43 . The release button slots  54  are designed to allow the release buttons  32  to protrude from the side edges  52  of the top case  50 . Depressing the release buttons  32  into the top case  50  releases the male insertion portion  8  from the female shroud portion  7 . When the user releases pressure from the release buttons  32 , the force from the connector bars  31  acts as a spring to cause the release buttons  32  to again protrude from the release button slots  54  along the side edges  52  of the top case  50 . 
     FIG. 2 depicts a perspective view of the female shroud portion  7  viewed into the top case  50 . As illustrated in FIG. 2, along a leading edge  58  of the top case  50  is a male insertion portion slot  56 . The male insertion portion  8  is inserted into the male insertion portion slot  56  to position the male insertion portion  8  within the female shroud portion  7 . The male insertion portion slot  56  forms an enclosed slot when the top case  50  and the bottom case  10  are attached together. 
     The top case  50  and bottom case  10  are attached to the leading edge  18  of the bottom case  10  and the leading edge  58  of the top case  50  are aligned, as are a back edge  64  of the top case  50  and the back edge  20  of the bottom case  10 . In the preferred embodiment, the top case  50  is glued or sonically welded to the bottom case  10  along all edges. It will be appreciated, however, that any method of attachment may be used without altering the spirit of the invention. 
     As illustrated in FIG. 2, the inner side of the top case has positioning apertures  65  which function with the positioning posts  26  (FIG. 1) to align the top case  50  and the bottom case  26  when the top case  50  and the bottom case  10  are bonded together. When the top case  50  and bottom case  10  are bonded together, the male insertion portion  8  is insertable between the bottom case  10  and the top case  50  through the sensor slot  56 . The provision of the elevation posts  24  (FIG. 1) allows the male insertion portion to pass beyond the contact block along the inside face  22  of the bottom case  10  until the male insertion portion  8  is fully inserted. 
     A cable guided  62  is also molded into the top case  50  to allow positioning of the cable  9 . The cable guide  62  is a slot along and a convex protrusion from the back edge  64  of to top case  50  as illustrated in FIG.  2 . The cable guide  62  holds the cable  9  in position to allow the cable  9  to connect with the contact block  40  without the cable  9  interfering with the inner workings of the connector  5 . 
     As illustrated in FIG. 2, the top case also has cable holders  85 ,  87  which also provide some stress release for the cable. In the present embodiment, the cable holders  85 ,  87  are L-shaped members offset from each other. Advantageously, the cable wires are weaved between the cable holders  85 ,  87  as represented by the dotted line  89  in FIG.  2 . In a preferred embodiment, the cable is bonded in place with epoxy to firmly fix the cable in place. 
     The top case tapers from the back edge  64  to the leading edge  58  such that the back edge  64  has a greater height than the leading edge  58  of the top case  50 . In addition to allowing cable access, this shape also aids the user in grasping the connector  5  to facilitate release of the male insertion portion from the female shroud portion  7 . 
     As illustrated in FIG. 2, the cable guide  62  is at the back edge  64  of the top case  50 . The cable  9  fits into the cable guide  62 . The cable  9  is secure between the cable mount  12  on the bottom case  10  and the cable guide  62  of the top case when the top case  50  and the bottom case  10  are bonded together. This prevents the cable  9  from shifting with respect to the female shroud  7 . 
     Also shown in FIG. 2 is a contact holder  80  within the upper case  50 . The contact holder  80  contains grooves  82  in which the contact block  40  is inserted. A mounting post  83  is configured to align the contact block  40  properly. The mounting post  83  mates with the positioning hole  85  (FIG. 1) of the contact block  40 . The mounting frame  46  of the contact block  40  is placed into the grooves  82  to hold the contact block  40  in place. As can be appreciated, each contact  44  on the contract block  40  may be connected to one or more wires from the cable  9 . Advantageously, the opposite end of the cable  9  is coupled to an external processor or monitor where the electrical signals are displayed and processed. 
     FIG. 2 also illustrates the release button slots  54  in the top case  50 . The release mechanisms  30  are inserted into the release button slots  54  so that the release buttons  32  protrude from the sides of the top case  50 . The spring members  31  of the release mechanisms  30  position along top case inner side slots  84 . After the release mechanisms  30  are inserted, the bottom case  10  is attached to the top case  50 , thereby securing the release mechanisms  30 , the cable  9 , and the contact block  40  in place. The female shroud portion is advantageously made of plastic, resin or the like. The contacts  42  for the contact block  40  are made from conductive material, such as copper or the like. 
     Insertion and release of the male portion  8  is exemplified in FIGS. 3,  4  and  5 . FIGS. 3 and 4 depict the bottom case  10  and the contact block  40 , but do not depict the top case  50 . This is to allow illustration of insertion of the male portion  8 . FIG. 3 also illustrates the release mechanisms  30  in phantom to assist in illustrating the release of the male insertion portion  8 . 
     In FIG. 3 the male insertion portion  8  is shown detached. The male insertion portion  8  has electrical contacts  102 , a plug portion  106 , and a locking hole  108 . A leading edge  110  of the male portion  106  is inserted into the sensor slot  56  of the connector  5 . When fully inserted, the electrical contacts  102  of the male insertion portion connect with the contacts  42  of the contact block  40 . This allows the signals being detected by the sensor (which connects to the electrical contacts  102  of the male insertion portion) to be transmitted via the contacts  42  to the cable  9  and to the monitor (not shown) via the cable  9 . As illustrated in FIGS. 3 and 4, the contact between the electrical contacts  102  and the contacts  42  is a friction contact. 
     The male insertion portion  8  is advantageously made from a two-piece assembly such as a molded plastic tab and etched flex circuit. The contacts  102  are made through etching of a copper coating or other metallic coating on one side of the polymer. As the male portion  8  is inserted, the leading edge  110  of the male portion  8  contacts the stop bar  16 , and the sensor lock  14  protrudes through the locking hole  108  as depicted in FIG.  4 . The sensor lock  14  prevents the male portion  8  from being removed from the connector  5  unless released. If force is applied to pull the male portion  8  from the connector  5 , the sensor lock  14  prevents the movement through the locking hole  108 . The sensor lock  14  and the stop bar  16  act to fix the male insertion portion firmly in place. This reduces noise which may be generated from sliding of the male insertion portion with respect to the contacts  42  on the contact block  40 . 
     In an embodiment with the retaining spring  14 , the retaining spring further acts to hold the male insertion portion  8  from being removed by bearing down on the male insertion portion in the are of the sensor lock  14 . 
     FIG. 4 shows the male portion  8  fully inserted into the female portion  7 . To release the male portion  8  from the female portion  7 , the user pushes both release buttons  32  into the female shroud portion  7 . When the release buttons  32  are pushed into the connector  5 , the lift tabs  34  raise the sensor plug portion  106  off of the sensor lock  14 . The lift tabs  34  are wedge shaped to raise the sensor plug portion  106 . The thickness of the lift tabs  34  is smallest on the inside edge and gradually increases as the lift tab  34  approaches the release button  32 . When the release buttons are pressed, it forces the thicker portions of the lift tabs  34  to wedge between the inner face  22  of the bottom case  10  and exert pressure on the sensor plug portion  106  to lift the sensor plug portion  106  off the sensor lock  14 . This allows the sensor or plug portion  106  to be removed from the connector  5  with a pulling motion. 
     At the same time the sensor plug portion  106  is raised off of the sensor lock  14 , the push tabs  35  press the sensor  100  out of the female shroud portion  7 . As the release buttons  32  are depressed, the leading edge of each push tab  36  comes in contact with the sensor plug portion  106  leading edge  110 . As further depression of the release buttons  32  occurs, the push tabs  36  move together. Due to the U-shape of the leading edge  110  of the sensor plug portion  106 , the action of the push tabs  36  coming together pushes the male insertion portion away from the stop bar  16 . This pushing motion moves the locking hole  108  away from the sensor lock  14 , thereby preventing the sensor lock  14  from re-engaging when the release buttons  32  are released. This allows a user to merely pull the male portion  100  from the connector  5  after the release buttons  32  have been depressed. 
     FIG. 4 shows the male insertion portion  8  completely locked in place in the connector  5 . The locking hole  108  of the male insertion portion  8  is engaged on the sensor lock  14  of the connector  5 . Also, the leading edge  110  of the sensor plug  106  is in contact with the stop bar  16  on the connector  5 . In this arrangement the electrical contacts  102  couple with the contacts  42  of the contact block  40 . FIGS. 3 and 4 also depict the cable  9  positioned with wires coupled to the connector tabs  44  of the contact block. Connection is advantageously through soldering. 
     FIG. 5 shows the complete connector  5  with the male insertion portion  8  inserted. The electrical connections within the female shroud portion  7  are substantially shielded from outside influence by the bottom case  10  and the top case  50 . The electrical connections are also substantially shielded from liquid in the environment. The entire assembly  120  shown in FIG. 5 presents a low-profile connector  5  that is easily grasped by the user. 
     Numerous variations and modification of the invention fall within the scope of the present invention. The preferred embodiment described above is, in all respects, illustrative, and not restrictive. Therefore, the scope of the invention is indicated by the appended claims, rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.