Patent Publication Number: US-2023134544-A1

Title: Sensor Assembly of a Sensing Device

Description:
FIELD OF THE INVENTION 
     The present invention relates to a sensing device and, more particularly, to a sensor assembly of the sensing device. 
     BACKGROUND 
     Catheters for invasive human body procedures, as well as other applications, use pressure sensors to improve existing procedures or conduct new procedures. The sensors are frequently small and fragile, and are difficult to install in the catheter without damaging the sensor. During insertion of the sensor into the catheter, the sensor can contact the walls of the catheter, resulting in damage to the sensor and unreliable sensor performance. Mounting the sensor in the proper location in the catheter is also difficult. In some applications, conditioning electronics connected to the sensor must first be removed before the sensor is carefully placed in the catheter, then the wires must be re-attached. The complicated re-attachment of the wires impairs the reliability of the electrical connection and the signal from the sensor. The sensor is also difficult to adhesively attach to the catheter in the proper orientation due to curing and positioning limitations in small spaces. 
     SUMMARY 
     A sensor assembly includes a carrier having a base wall and a pair of side walls extending from the base wall, and a sensor mounted on the base wall between the side walls. Each of the side walls has a side step between a first side section and a second side section extending from the first side section along a longitudinal direction of the carrier. A sensor die of the sensor is spaced in a width direction perpendicular to the longitudinal direction by a first lateral gap distance from the first side section and by a second lateral gap distance from the second side section. The second lateral gap distance is greater than the first lateral gap distance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described by way of example with reference to the accompanying Figures, of which: 
         FIG.  1    is a perspective view of a sensor assembly according to an embodiment; 
         FIG.  2    is a sectional perspective view of a carrier of the sensor assembly; 
         FIG.  3    is a bottom perspective view of the carrier; 
         FIG.  4    is a top view of a carrier according to another embodiment; 
         FIG.  5    is a sectional side view of the carrier of  FIG.  4   ; 
         FIG.  6    is a top view of the sensor assembly; 
         FIG.  7    is a sectional side view of the sensor assembly; 
         FIG.  8    is a perspective view of a sensor assembly according to another embodiment with a pair of shells separate from one another; 
         FIG.  9    is a perspective view of the sensor assembly of  FIG.  8    with the pair of shells connected to one another; 
         FIG.  10    is a perspective view of a sensing device according to an embodiment; 
         FIG.  11    is a sectional side view of the sensing device of  FIG.  10   ; and 
         FIG.  12    is a sectional side view of a sensing device according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT(S) 
     Exemplary embodiments of the present disclosure will be described hereinafter in detail with reference to the attached drawings, wherein like reference numerals refer to like elements. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will convey the concept of the disclosure to those skilled in the art. In addition, in the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it is apparent that one or more embodiments may also be implemented without these specific details. 
     Throughout the specification, directional descriptors are used such as “longitudinal”, “width”, and “vertical”. These descriptors are merely for clarity of the description and for differentiation of the various directions. These directional descriptors do not imply or require any particular orientation of the disclosed elements. 
     Throughout the drawings, only one of a plurality of identical elements may be labeled in a figure for clarity of the drawings, but the detailed description of the element herein applies equally to each of the identically appearing elements in the figure. 
     A sensor assembly  10  according to an embodiment is shown in  FIGS.  1 ,  6 , and  7   . The sensor assembly  10  includes a carrier  100  and a sensor  200  mounted on the carrier  100 . 
     The carrier  100 , as shown in  FIGS.  1 - 3   , extends from a proximal end  102  to a distal end  104  along a longitudinal direction L of the carrier  100 . The carrier  100  has a base wall  110  extending between the proximal end  102  and the distal end  104  and a pair of side walls  140  extending from the base wall  110  in a vertical direction V perpendicular to the longitudinal direction L. The base wall  110  and the side walls  140  define a sensor receiving space  160  shown in  FIG.  1   . 
     The base wall  110 , as shown in  FIGS.  2  and  3   , has a sensing opening  118  extending through the base wall  110  in the vertical direction V. In another embodiment, the sensing opening  118  could be a recess in the base wall  110  facing the sensor receiving space  160  that does not extend fully through the base wall  110  in the vertical direction V. The base wall  110  has a rear base section  120  at the proximal end  102  and a front base section  130  at the distal end  104  separated from the rear base section  120  along the longitudinal direction L by the sensing opening  118 . 
     As shown in  FIG.  2   , the rear base section  120  has a base step  122  between a first base step section  124  at the proximal end  102  and a second base step section  126  extending from the first base step section  124 . The first base step section  124  has a first base thickness  125  along the vertical direction V and the second base step section  126  has a second base thickness  127  along the vertical direction V. The first base thickness  125  is greater than the second base thickness  127 . 
     The front base section  130 , as shown in  FIGS.  2  and  3   , has a pulling device  132 . In the embodiment shown in  FIGS.  2  and  3   , the pulling device  132  is an eyelet  134  extending through the base wall  110  in the vertical direction V. In the shown embodiment, the eyelet  134  is a symmetrical, circular passageway extending through the base wall  110 . In other embodiments, the eyelet  134  may be a passageway of any other shape extending through the base wall  110 , including any symmetrical or asymmetrical shape. 
     In another embodiment shown in  FIGS.  4  and  5   , the pulling device  132  in the front base section  130  is a hook  136  extending from an inner base surface  112  of the base wall  110  in the vertical direction V; as shown in  FIGS.  2 ,  4 , and  5   , the base wall  110  has the inner base surface  112  and an outer base surface  114  opposite the inner base surface  112  in the vertical direction V. The hook  136  shown in  FIGS.  4  and  5    is merely exemplary and, in other embodiments, the hook  136  may be any element that extends from the inner base surface  112  of the base wall  110  in the vertical direction V, may be positioned asymmetrically or symmetrically on the carrier  100 , and may be a single hook  136  or a plurality of hooks  136  positioned in any arrangement. In other embodiments, the pulling device  132  in the front base section  130  may be any other type of recess or protrusion that is capable of being engaged and pulled by an external element, as described in greater detail below. 
     Each of the side walls  140 , as shown in  FIG.  2   , has a base end  142  connected to a side of the base wall  110  and a free end  144  opposite the base end  142  in the vertical direction V. Each of the side walls  140  extends along the longitudinal direction L from a first end  147  to an opposite second end  148 . In the shown embodiment, the second end  148  has a sloped shape  149  that is inclined with respect to the vertical direction V and the longitudinal direction L. 
     As shown in  FIG.  1   , each of the side walls  140  has a side step  150 . The side step  150 , as shown in  FIG.  2   , is between a first side section  152  and a second side section  156  of the side wall  140 . The second side section  156  extends from the first side section  152  along the longitudinal direction L. The first side section  152  has a first side thickness  154  in a width direction W perpendicular to the vertical direction V and the longitudinal direction L. The second side section  156  has a second side thickness  158  in the width direction W. The first side thickness  154  is greater than the second side thickness  158 . 
     At the free end  144 , each of the side walls  140  has a profiled side edge  146 , as shown in  FIG.  1   , on a side facing away from the sensor receiving space  160 . In the shown embodiment, the profiled side edge  146  is a straight chamfer intersecting the free end  144 . In other embodiments, the profiled side edge  146  could have a curved cross-sectional shape. 
     The base wall  110  has a profiled base edge  116 , as shown in  FIG.  3   , on opposite sides of the outer base surface  114  of the base wall  110  in the width direction W. Each of the profiled base edges  116 , in the shown embodiment, is a straight chamfer intersecting the base end  142  of one of the side walls  140 . In other embodiments, the profiled base edges  116  could have a curved cross-sectional shape. The shape of the profiled base edges  116  corresponds to the shape of the profiled side edges  146  in an embodiment. In another embodiment, the shape of the profiled base edges  116  may be different from the shape of the profiled side edges  146 , provided that the profiled base edges  116  and the profiled side edges  146  serve the function described below. In another embodiment, the profiled base edges  116  and the profiled side edges  146  could be omitted. 
     The carrier  100 , as shown in  FIGS.  2  and  3   , has a carrier positioning device  170  in the rear base section  120 . In the shown embodiment, the carrier positioning device  170  is a peg  172  disposed on the outer base surface  114  of the base wall  110  and extending from the outer base surface  114  in the vertical direction V. In other embodiments, the carrier positioning device  170  can be any other type of protrusion extending from the outer base surface  114 . In the shown embodiment, the carrier positioning device  170  is a single peg  172  positioned approximately centrally on the outer base surface  114 ; in other embodiments, the carrier positioning device  170  could be one peg  172  positioned off-center or asymmetrically on the outer base surface  114 , or could be a plurality of pegs  172  positioned symmetrically or asymmetrically on the outer base surface  114 . In further embodiments, for example as described below, the carrier positioning device  170  can be a recess extending through the base wall  110  in the vertical direction V, and likewise could be one recess or a plurality of recesses, and could be positioned symmetrically or asymmetrically. 
     The sensor  200  includes a sensor die  210  and a plurality of wires  220  connected to the sensor die  210 , as shown in  FIG.  1   . In an embodiment, the sensor die  210  is a pressure sensor, for example a piezoresistive pressure sensing die. In other embodiments, the sensor die  210  may be any other type of pressure sensor, or may be any sensor capable of detecting other qualities in addition to or alternatively to a pressure. The wires  220  are a plurality of conductors that transmit a signal of the sensor die  210  to an element external from the sensor assembly  10 . 
     Assembly of the sensor assembly  10  will now be described in greater detail with reference to  FIGS.  1 ,  6 , and  7   . 
     The sensor  200  is mounted in the sensor receiving space  160  on the base wall  110  and between the side walls  140  as shown in  FIGS.  6  and  7   . The sensor die  210  has a secured portion  212  disposed on the second base step section  126 . In the shown embodiment, the secured portion  212  abuts against the base step  122  to locate the sensor die  210  in the sensor receiving space  160  along the longitudinal direction L. 
     As shown in  FIGS.  6  and  7   , a sensor adhesive  230  attaches the sensor die  210  to the carrier  100 . The sensor adhesive  230  is deposited or dispensed over the secured portion  212  of the sensor die  210  and the wires  220 . In the shown embodiment, the sensor adhesive  230  flows around the sensor die  210  and under the wires  220  to the position shown in  FIG.  7   , in which the sensor adhesive  230  is disposed between the inner base surface  112  of the rear base section  120  and the secured portion  212 . In other embodiments, the sensor adhesive  230  may remain only on top of the sensor die  210  and the wires  220 , or may be disposed both between the inner base surface  112  of the rear base section  120  and the secured portion  212  and on top of the sensor die  210  and the wires  220 . 
     The sensor adhesive  230  may be any type of adhesive curable by a light, such as an epoxy curable by an ultraviolet light, may be any type of adhesive curable by the application of heat, or may be any type of adhesive curable by a chemical catalyst. The sensor adhesive  230 , in a cured state, secures the secured portion  212  of the sensor die  210  and the wires  220  to the carrier  100 . The sensor die  210  has a free portion  214  extending from the secured portion  212  and positioned over the sensing opening  118 . 
     As shown in  FIG.  6   , the sensor die  210  is secured in a position spaced apart from the side walls  140  in the width direction W. The sensor die  210  is spaced by a first lateral gap distance G 1  in the width direction W from the first side section  152  and by a second lateral gap distance G 2  in the width direction W from the second side section  156 . The second lateral gap distance G 2  is greater than the first lateral gap distance G 1 . In the embodiment shown in  FIGS.  6   , the sensor adhesive  230  is disposed in an area between the side walls  140  and the sensor die  210  having the first lateral gap distance G 1 . In the embodiment shown in  FIG.  6   , the sensor die  210  is centered between the side walls  140  in the width direction W; the first lateral gap distance G 1  is the same on both sides of the sensor die  210  and the second lateral gap distance G 2  is the same on both sides of the sensor die  210 . In other embodiments, the sensor die  210  may be positioned off-center between the side walls  140  in the width direction W, and the first lateral gap distance G 1  and the second lateral gap distance G 2  may be different on opposite sides of the sensor die  210  in the width direction W. 
     The positioning of the sensor die  210  with the first lateral gap distance G 1  and the second lateral gap distance G 2  from the side walls  140 , and the omission of a front wall in the carrier  100 , prevents the sensor die  210  from contacting the carrier  100 . The second lateral gap distance G 2  that is greater than the first lateral gap distance G 1  is aligned with the free portion  214  of the sensor die  210  that is a sensing area of the sensor die  210 . Limiting damage to the sensor die  210  and/or limiting output errors from the sensor die  210  by maintaining spacing from the carrier  100  in this manner helps to ensure accurate readings from the sensor die  210 . 
     As shown in  FIGS.  6  and  7   , the wires  220  extend from the sensor die  210  over the first base step section  124  and out the proximal end  102  of the carrier  100 . As in the shown embodiment, the wires  220  may also be secured to the inner base surface  112  of the base wall  110  by the sensor adhesive  230 . In the shown embodiment, the sensor adhesive  230  is positioned in a portion of the first base step section  124 . In another embodiment, the sensor adhesive  230  can be deposited within an entirety of the first base step section  124  and extends to the proximal end  102  of the carrier  100  or beyond the proximal end  102  of the carrier  100  in the longitudinal direction L. 
     In the embodiments shown in  FIGS.  1 - 7   , the carrier  100  is monolithically formed in a single piece. In another embodiment, the carrier  100  may be formed of a plurality of separate pieces, of the same material or of different materials, and assembled together to form the carrier  100  described above. 
     In an embodiment, the carrier  100  is formed from an at least partially translucent material, i.e. a translucent or a transparent material, such as polycarbonate. In an embodiment in which the carrier  100  is formed from an at least partially translucent material, the sensor adhesive  230  can be cured in the position shown in  FIG.  7    by applying a light capable of curing the sensor adhesive  230 , such as a light in the visible spectrum or an ultraviolet light, onto the carrier  100  such that the light passes through the at least partially translucent material of the carrier  100  and reaches the sensor adhesive  230 . 
     In another embodiment, the carrier  100  may be formed from an opaque material. In this embodiment, the sensor adhesive  230  can be cured in the position shown in  FIG.  7    by applying a heat to the sensor assembly  10  that cures the sensor adhesive  230 , or can be cured in the position shown in  FIG.  7    by a chemical catalyst, for example as a two-part epoxy. 
     In another embodiment, shown in  FIGS.  8  and  9   , the carrier  100  is formed of a pair of shells  190 ,  191  that are mateable together. The carrier  100  is shown formed from two shells  190 ,  191  in the embodiment of  FIGS.  8  and  9   . In other embodiments, the carrier  100  may be formed of more than two shells  190 ,  191 . Each of the shells  190 ,  191  is monolithically formed in a single piece and may be formed of any material of the carrier  100  described above. 
     As shown in  FIGS.  8  and  9   , each of the shells  190 ,  191  has a portion of the base wall  110 , including a portion of the sensing opening  118 , and one of the side walls  140 . In the embodiment shown in  FIGS.  8  and  9   , each of the shells  190 ,  191  also has a portion of a top wall  182  and a portion of an end wall  184  of the carrier  100 . The carrier  100  may be formed of the pair of shells  190 ,  191  in other embodiments, such as the embodiments of  FIGS.  1 - 7   , in which the carrier  100  does not have the top wall  182  or the end wall  184 . In other embodiments, the shells  190 ,  191  could be different segments of the carrier  100  separated along different directions, for example one of the shells  190  could have an entirety of the base wall  110  and the sensing opening  118  while the other of the shells  192  is a lid having at least the side walls  140 . 
     In the embodiment shown in  FIGS.  8  and  9   , one of the shells  190 ,  191  has the carrier positioning device  170 . In other embodiments, a portion of the carrier positioning device  170  could be positioned on each of the shells  190 ,  191 . The carrier positioning device  170  is a peg  172  in the shown embodiment and, in other embodiments, could be any other type of protrusion or a recess extending through the base wall  110  as described above. 
     Each of the shells  190 ,  191 , as shown in  FIG.  8   , has a locating feature  192 . In the shown embodiment, a first shell  190  of the shells  190 ,  191  has a locating protrusion  194  extending from the portion of the base wall  110  and a second shell  191  of the shells  190 ,  191  has a locating recess  196  extending into the portion of the base wall  110 . In the shown embodiment, the locating protrusion  194  is a single rectangular shaped protrusion and the locating recess  196  is a single rectangular shaped recess. In other embodiments, the locating protrusion  194  could be any other type of protrusion, such as a rounded protrusion, and the locating recess  196  could be any other type of recess, such as a concave divot, that corresponds to the locating protrusion  194 . In another embodiment, one of the locating features  192  could have a plurality of locating protrusions  194  and the other of the locating features  192  could have a plurality of locating recesses  196 . 
     To form the sensor assembly  10 , the sensor  200  is first mounted on the base wall  110  of one of the shells  190 , as shown in  FIG.  8   . The sensor  200  is mounted in position on the base wall  110  as described in detail with respect to  FIGS.  6  and  7    above. 
     With the sensor  200  mounted to one of the shells  190 , the carrier  100  is formed by moving the shells  190 ,  191  together along the width direction W to a formed state shown in  FIG.  9   . The locating features  192  cooperate with one another to ensure that the shells  190 ,  191  are in a proper position with respect to one another in the formed state; the locating protrusion  194  extends into the locating recess  196  in the shown embodiment. The portions of the shells  190 ,  191 , such as the respective portions of the base wall  110 , the top wall  182 , and the end wall  184 , abut one another as shown in  FIG.  9    to form the walls  110 ,  182 ,  184  of the carrier  100  in the formed state. The shells  190 ,  191  can be attached to one another in the formed state shown in  FIG.  9    by an adhesive, by plastic welding, or by any other form of attachment. 
     A sensing device  1  according to an embodiment is shown in  FIGS.  10  and  11   . The sensing device  1  includes a body  20  and the sensor assembly  10  according to the embodiments described above disposed in the body  20 . Not all of the elements of the sensor assembly  10  are labeled in detail in  FIGS.  10  and  11    for clarity of the drawings, but the reference numbers and description of the sensor assembly  10  above with respect to  FIGS.  1 - 3 ,  6 , and  7    apply equally to the sensor assembly  10  shown in  FIGS.  10  and  11   . 
     The body  20 , as shown in  FIGS.  10  and  11   , extends along the longitudinal direction L and has a receiving passageway  22  extending through the body  20  along the longitudinal direction L. An inner surface profile  24  of the body  20  forms and defines the receiving passageway  22 . In the shown embodiment, the body  20  is a cylindrical member having a circular cross-section and the inner surface profile  24  has a circular cross-section. In other embodiments, the body  20  may be a tubular member having any cross-sectional shape, such as a square cross-section, a rectangular cross-section, or a curved cross-section other than a circle, and the inner surface profile  24  correspondingly may have any cross-sectional shape. 
     As shown in  FIGS.  10  and  11   , the body  20  has a sensing window  26  extending into the body  20  in the vertical direction V and communicating with the receiving passageway  22 . The sensing window  26  extends along a portion of the body  20  along the longitudinal direction L. 
     As shown in  FIG.  11   , the body  20  has a body positioning device  28  opposite a portion of the sensing window  26  along the vertical direction V. In the shown embodiment, the body positioning device  28  is a recess  29  extending through the body  20 . In the shown embodiment, the body positioning device  28  is a single recess  29  positioned approximately centrally on the body  20  along the longitudinal direction L; in other embodiments, the body positioning device  28  could be one recess  29  positioned off-center on the body  20  or could be a plurality of recesses  29  positioned symmetrically or asymmetrically on the body  20 . In other embodiments, the body positioning device  28  may be a protrusion extending from the body  20  into the receiving passageway  22  along the vertical direction V, and likewise could be one protrusion or a plurality of protrusions, and could be positioned symmetrically or asymmetrically. 
     The installation of the sensor assembly  10  in the body  20  to form the sensing device  1  will now be described in greater detail with respect to  FIGS.  10  and  11   . 
     The sensor assembly  10 , formed as any of the embodiments described above with respect to  FIGS.  1 - 9   , is positioned at an end of the receiving passageway  22  of the body  20 . A tool is attached to the pulling device  132  at the distal end  104  of the carrier  100 . The tool may be a wire or a protrusion passing through or otherwise engaging the eyelet  134  formed as the pulling device  132  in the embodiment shown in  FIGS.  10  and  11   . In another embodiment in which the pulling device  132  is the hook  136 , as shown in  FIGS.  4  and  5    and described above, the tool may be a wire or a catch engaging the hook  136 . 
     The sensor assembly  10  is pulled into and along the receiving passageway  22  in the longitudinal direction L by the pulling device  132  and using the tool. The profiled side edges  146  of the side walls  140  and the profiled base edges  116  of the base wall  110  are shaped to correspond to the inner surface profile  24  of the body  20 , such that the carrier  100  can fit in the receiving passageway  22  and move along the receiving passageway  22  without significant obstruction. 
     Pulling the sensor assembly  10  into the body  20  by the pulling device  132  limits damage to the sensor die  210  by applying the pulling force on the carrier  100 . Further, as the carrier  100  fits in the receiving passageway  22 , the carrier  100  protects the sensor die  210  from contact with the body  20  as the sensor assembly  10  is moved. The use of the pulling device  132  to move the sensor assembly  10  also allows the wires  220  to remain connected to the sensor die  210  and sensor conditioning electronics, and prevents additional steps from complicating the assembly process. 
     The sensor assembly  10  is pulled along the receiving passageway  22  until the carrier positioning device  170  reaches the body positioning device  28 , as shown in  FIG.  11   . The carrier positioning device  170  cooperates with the body positioning device  28  to position the sensor assembly  10  in an installed position I in the receiving passageway  22 . In the shown embodiment, the carrier positioning device  170  embodied as the peg  172  engages the body positioning device  28  embodied as the recess  29 . In another embodiment, the body positioning device  28  may be the peg extending into the receiving passageway  22  and the carrier positioning device  170  may be the recess receiving the peg. In embodiments in which the carrier positioning device  170  and the body positioning device  28  are each a plurality of elements, the carrier positioning device  170  and the body positioning device  28  have the same number of elements and the elements individually correspond in position to engage one another. 
     In another embodiment, shown in  FIG.  12   , the carrier positioning device  170  is the eyelet  134  extending through the base wall  110 . In this embodiment, when the eyelet  134  is aligned with the recess  29  of the body positioning device  28  along the vertical direction V, a pin  40  is inserted to extend through the recess  29  and the eyelet  134  to secure the sensor assembly  10  in the installed position I. In other embodiments, an eyelet or passageway positioned elsewhere on the base wall  110  may receive the pin  40 . 
     Once the sensor assembly  10  is in the installed position I in the receiving passageway  22 , a device adhesive  30  is applied as shown in  FIGS.  11  and  12    to secure the sensor assembly  10  in the installed position I. The device adhesive  30  is disposed between the carrier  100  and the body  20  around the carrier positioning device  170  and the body positioning device  28 . The device adhesive  30  may be an epoxy or any other type of adhesive, and may be curable by light, including light in the visible spectrum or ultraviolet light, heat, or by chemical catalysts. The engagement of the carrier positioning device  170  with the body positioning device  28  ensures that the carrier  100  and the sensor  200  held by the carrier  100  are properly positioned within the body  20  prior to applying the device adhesive  30 . 
     In an embodiment, the sensing device  1  is part of a catheter used in medical applications. In this embodiment, the sensor die  210  can be used to detect a pressure of a fluid, the fluid contacting the sensor die  210  by passing through the sensing window  26  and into the receiving passageway  22 , and can transmit a signal representing the pressure along the wires  220 . In other embodiments, the sensing device  1  could be another type of medical device, or could be part of any device requiring the sensor  200  to be disposed in the body  20  to measure pressure or other qualities.