Abstract:
A vibration transducer specially configured for attachment to a subject&#39;s nose for producing an electrical output signal relating to a subject&#39;s snoring pattern. The transducer is shaped so as to have a rectangular portion for bridging the dorsum at least one polygonal pad area adapted to be adhesively secured to the ala nasi. The transducer is a laminated arrangement incorporating a polyvinylidene fluoride film exhibiting piezoelectric properties.

Description:
BACKGROUND OF THE INVENTION 
   I. Field of the Invention 
   This invention relates generally to electronic transducers for use in monitoring snoring episodes during sleep studies, and more particularly to a transducer especially designed to be worn on the nose for producing an electrical output proportional to vibration of selected portions of the nose as snoring takes place. 
   II. Discussion of the Prior Art 
   In U.S. Pat. No. 5,311,875 to Stasz, which is hereby incorporated by reference, there is described a system for electronically monitoring breathing patterns. The system included a transducer, the active element of which comprises a film of polyvinylidene fluoride (PVDF). As those skilled in the art appreciate, this material exhibits both pyroelectric and piezoelectric properties. 
   In accordance with the Stasz &#39;875 patent, the transducer was adapted to be mounted on the upper lip of a subject where it would be exposed not only to vibration resulting from snoring but also thermal differences due to respiratory air flow during nasal breathing. The piezoelectric properties of the PVDF film produces a signal proportional to vibration and the pyroelectric properties produces a signal proportional to temperature fluctuations. In a subsequent Stasz et al. U.S. Pat. No. 6,254,545, there is described a combination thermal and vibration sensor for use in sleep monitor equipment where, again, a thin film of PVDF material is the active element. The PVDF film layer is sandwiched between an outer adhesive tape layer and an inner double-sided layer of adhesive tape. The transducer was particularly shaped for placement on the upper lip such that air entering and leaving the nostrils would impinge upon the transducer and so that a further portion is suspended from the upper lip but overhangs the mouth. The contents of the Stasz &#39;545 patent are also hereby incorporated by reference as if set forth in full herein. 
   U.S. patent application Ser. No. 09/634,148, filed Aug. 8, 2002, which is assigned to the assignee of the present application, describes a vibration transducer based upon PVDF technology where the transducer comprises a generally rectangular patch that is adapted for placement on a subject&#39;s throat for the purpose of picking up vibrations caused by snoring. 
   Experience has shown that while each of the above-described transducer designs successfully operates for its intended purpose, each has its own type of defect that some patients find objectionable. In particular, the Stasz &#39;875 patent and the Stasz et al. &#39;545 patent are designed to be adhesively adhered to a patient&#39;s upper lip. If the person that is the subject of a sleep study has a moustache, it becomes somewhat difficult to adhesively affix the transducer to the upper lip and the moustache prevents more intimate contact with the skin of the lip such that vibrations produced by snoring are greatly attenuated. Moreover, subjects have complained about an objectionable tickling response when the transducer is affixed to the upper lip. The transducer that is the subject of pending U.S. application Ser. No. 09/634,148 must be placed at a so-called “sweet spot” on the neck, which is sometimes difficult to locate. In locating it, the subject is asked to hum and while doing so, the technician at the sleep lab must feel about the subject&#39;s throat to find the location where the vibration resulting from the hum is a maximum. 
   It is accordingly a principal object of the present invention to provide a vibration transducer that obviates the drawbacks mentioned above while still providing a robust electrical output signal during episodes of snoring so that information relating to snoring patterns can be discerned. 
   SUMMARY OF THE INVENTION 
   In accordance with this invention, there is provided a thin, flexible, laminated vibration transducer that is adapted for placement on a subject&#39;s nose for producing an electrical signal related to snoring episodes. The transducer comprises an outer layer of adhesive tape having adhesive on one major surface thereof. An intermediate layer of a flexible, conformable plastic film exhibiting piezoelectric properties and having a pattern of metallization on opposed major surfaces thereof is adhered to the outer layer of adhesive tape. First and second elongated conductors or wires, each having an electrode at one end and an electrical connector at another end are arranged such that the electrode on the first conductor is held in contact with the pattern of metallization on one of the opposed major surfaces of the layer of plastic film by the outer layer of adhesive tape and the electrode on the one end of the second conductor is held in contact with the pattern of metallization on the opposite side of the film layer using an inner layer of adhesive tape that has adhesive on each of its opposed major surfaces. The outer and inner layers of adhesive tape have a generally rectangular portion for spanning the dorsum of the nose and at least one integrally attached pad portion for attachment to an ala nasi. 
   It has been determined that the vibration of the ala nasi during snoring is readily detected by a PVDF transducer. 

   
     DESCRIPTION OF THE DRAWINGS 
     The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of a preferred embodiment, especially when considered in conjunction with the accompanying drawings in which like numerals in the several views refer to corresponding parts. 
       FIG. 1  is a perspective view of a first embodiment of the invention; 
       FIG. 2  is an exploded view of the embodiment of  FIG. 1 ; 
       FIG. 3  is an exploded sectional view of the embodiment of  FIG. 1 ; 
       FIG. 4  shows the embodiment of  FIG. 1  in place on the nose of a subject; 
       FIG. 5  is a perspective view of an alternative embodiment of the invention; 
       FIG. 6  is an exploded view of the embodiment of  FIG. 5 ; and 
       FIG. 7  is a view illustrating the embodiment of  FIG. 5  affixed to the nose of a subject. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the device and associated parts thereof. Said terminology will include the words above specifically mentioned, derivatives thereof and words of similar import. 
   Referring first to  FIG. 1 , there is indicated generally by numeral  10  a nasal vibration sensor in accordance with the present invention. It comprises a generally rectangular portion  12  with integrally attached polygonal pad portions  14  and  16  on opposed ends of the central rectangular portion. The pad portions may be polygonal in shape, as illustrated, or they may be somewhat rounder or oval in shape. Exiting opposed ends of the transducer are electrical conductors or wires  18  and  20  which lead to connectors  21  and  22  that are adapted to mate with input terminals of an amplifying and signal processing circuit (not shown). 
   Referring next to  FIG. 2 , the exploded view shows that the transducer is of a laminated construction, having an outer layer  24  of adhesive tape, an intermediate layer of polyvinylidene fluoride (PVDF) film  26  and an inner layer  28  of double-sided adhesive tape with an adhesive layer on opposed major surfaces thereof. 
   The PVDF film  26  has a layer of metallization  28  on opposed major surfaces thereof. The metallization is represented in  FIG. 2  by the cross-hatching on the PVDF film layer  26 . It is coextensive with the outer layer  24  in terms of area. 
   With continued reference to  FIG. 2 , it will be seen that on the end of the conductor or wire  18  is an electrode member  30  and on the end of the wire  20  opposite from the connector  22  is a similar electrode member  32 . In its laminated condition, the electrode  30  is held in contact with the layer of metallization  28  on the upper surface of the film layer  26  while electrode  32  engages the pattern of metallization on the undersurface of the layer  26 . 
   Referring now to  FIG. 3 , which is an exploded cross-sectional view taken through the transducer  10 , it will be seen that there is an adhesive layer  25  on the undersurface of the tape substrate  24 . Likewise, the tape substrate  29  has an adhesive layer  34  on its upper surface and at an adhesive layer  36  on its lower or undersurface. To protect the adhesive layer  36  from contamination prior to use, a release liner  38 , which is relatively unaggressively adhered to the adhesive layer  36  is provided. The adhesive layer  36  on the underside of tape substrate  29  is selected so as to be comfortably removable from a subject&#39;s skin, yet adherent enough so as to maintain the transducer in place for a period of several hours. 
   Once laminated, the adhesive layer  25  bonds to the adhesive layer  34  sandwiching the electrode  30 , the PVDF film layer  26  and the electrode  32  therebetween. Without limitation, the rectangular portion  12  may be in a range of 3 cm to 5 cm long and 7 mm wide. The pads  14  and  16  may have an area of about 2.25 t0 3 sq. cm. 
   Referring now to  FIG. 4 , in use, the release liner  38  is peeled free from the adhesive layer  36  and the rectangular portion  12  of the laminated transducer is placed across the dorsum of the subject&#39;s nose and with the pad areas  14  and  16  being adhesively adhered to the ala nasi. The wires  18  and  20  pass over the subject&#39;s cheeks and behind the ears where a connection is made between the connectors  21  and  22  and an electronics module (not shown) for receiving and processing signals derived from the transducer  10 . It is found that when a person snores, the ala nasi vibrate and those vibrations are picked up by the PVDF film transducer and converted to an electrical signal proportional to the detected vibration signal. 
   Alternative Embodiment 
   Referring to  FIGS. 5-7 , the alternative embodiment differs from the previously described embodiment in only two respects. First, only one pad  16 ′ is integrally attached to one end of the rectangular portion  12 ′ of the transducer and the PVDF film layer  26 ′ is coextensive with the pad area of the outer layer of adhesive tape  24 ′. 
   When the transducer  10 ′ is laminated, the adhesive on the undersurface of the outer adhesive tape layer  24 ′ holds the electrode  30 ′ to the upper surface of the PVDF film layer  26 ′. Likewise, the adhesive layer on the upper surface of the tape  29 ′ adheres the electrode  32 ′ to the pattern of metallization on the undersurface of the PVDF film layer  26 ′. Furthermore, the adhesive on the undersurface of the outer tape layer  24 ′ bonds to the adhesive on the upper surface of the inner adhesive tape layer  29 ′ except where the film layer  26 ′ is interposed. A release liner is also adhered to the under surface of the inner layer  29 ′ to protect the adhesive on that surface prior to its being used to adhere the transducer device to the nose of a subject. 
     FIG. 7  shows the alternative embodiment of  FIGS. 5 and 6  affixed to a subject. Here, the release layer has been removed and the adhesive on the under surface of the layer  29 ′ attaches the transducer of the subject&#39;s nose such that the rectangular portion  12 ′ of the transducer overlays the dorsum and the pad area  16 ′ is bonded to the ala nasi on only one side of the side. 
   The choice of using a transducer as in  FIG. 4  or as in  FIG. 7  can depend on the type of data recorder that may be available in a sleep lab. If higher amplitude input signals are required, the transducer of  FIG. 4  would be the choice. The transducer of  FIG. 4  also offers an advantage of added security in the event one pad area should come loose. The sensor of  FIG. 7  offers a lower cost alternative. 
   This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.