Pressure sensor assembly and implantable medical device including same

Abstract

Various embodiments of a pressure sensor assembly and an implantable medical device including such assembly are disclosed. The assembly includes a sensor housing, a cavity disposed within the sensor housing, and a diaphragm disposed within the sensor housing and extending through the cavity to define a measurement chamber and an input chamber of the cavity. The diaphragm defines a first electrode plate. The assembly further includes a second electrode plate disposed on or at least partially within the first surface of the sensor housing, and a passageway that extends between a side surface of the sensor housing and the input chamber and is configured to transfer ambient pressure to the diaphragm. The first electrode plate and the second electrode plate form a variable capacitor disposed along a sensor axis that is substantially orthogonal to the first and second electrode plates.

Description

PRESSURE SENSOR ASSEMBLY AND IMPLANTABLE MEDICAL DEVICE INCLUDING SAMECROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 624,572, filed January 24, 2024, the disclosure of which is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] This disclosure generally relates to a pressure sensor assembly and more particularly to an implantable medical device that includes a pressure sensor assembly.BACKGROUND

[0003] A variety of medical devices for delivering a therapy and / or monitoring a physiological condition have been clinically implanted or proposed for clinical implantation in patients. Such implantable medical devices can deliver electrical stimulation or drug therapy to, and / or monitor conditions associated with, the heart, muscle, nerve, brain, stomach, or other organs or tissue, as examples. Implantable medical devices can include or be coupled to one or more physiological sensors, which can be used with the device to monitor signals related to various physiological conditions from which a patient state or the need for a therapy can be assessed.

[0004] Pressure sensors may be employed with implantable medical devices as physiological sensors and can be configured to detect, e.g., changes in blood pressure. Example pressure sensors that may be useful for measuring blood pressure may employ capacitive, piezoelectric, piezoresistive, electromagnetic, optical, resonant-frequency, or thermal methods of pressure transduction.SUMMARY

[0005] The techniques of this disclosure generally relate to a pressure sensor assembly and implantable medical device (IMD) that includes such assembly. The assembly can include a diaphragm disposed within a cavity of a sensor housing such that the diaphragm extendsthrough the cavity and defines a measurement chamber and an input chamber of the cavity. The diaphragm also provides or defines a first electrode plate, and a second electrode plate can be disposed on or at least partially within a surface of the sensor housing along a sensor axis, where the second electrode plate is substantially parallel to the first electrode plate. The first and second electrode plates provide a variable capacitor that is disposed along the sensor axis. One or more passageways can each extend between an inlet disposed in a side surface of the sensor housing and the input chamber, where each passageway is configured to transfer ambient pressure from an atmosphere adjacent to the pressure sensor assembly to the diaphragm. In one or more embodiments, the variable capacitor of the assembly can be configured to provide a first capacitance reading based upon a distance between the first electrode plate and the second electrode plate as such distance changes due to deflection of the diaphragm caused by pressure changes in the input chamber in response to ambient pressure changes. The first capacitance reading can be compared to a second capacitance reading provided by a reference capacitor of the assembly to determine a pressure change of the environment adjacent to the assembly using any suitable technique.

[0006] In one example, aspects of this disclosure relate to a pressure sensor assembly including a sensor housing having a first surface, a second surface substantially parallel to the first surface, and a side surface that extends between the first and second surfaces; a cavity disposed within the sensor housing along a sensor axis that is substantially orthogonal to the first surface; and a diaphragm disposed within the sensor housing along the sensor axis and including a first major surface and a second major surface. The first major surface is substantially orthogonal to the sensor axis. The diaphragm extends through the cavity and defines a measurement chamber and an input chamber of the cavity. Further, at least a portion of the diaphragm disposed in the cavity defines a first electrode plate. The assembly further includes a second electrode plate disposed on or at least partially within the first surface of the sensor housing along the sensor axis, where the second electrode plate is substantially parallel to the first electrode plate; and a passageway that extends between an inlet disposed in the side surface of the sensor housing and the input chamber and that is configured to transfer ambient pressure to the diaphragm. The first electrode plate and the second electrode plate form a variable capacitor disposed along the sensor axis.

[0007] In another example, aspects of this disclosure relate to an implantable medical device including a device housing and a pressure sensor assembly that forms a portion of the device housing. The pressure sensor assembly includes a sensor housing having a first surface, a second surface substantially parallel to the first surface, and a side surface that extends between the first and second surfaces; a cavity disposed within the sensor housing along a sensor axis that is substantially orthogonal to the first surface; and a diaphragm disposed within the sensor housing along the sensor axis and including a first major surface and a second major surface. The first major surface is substantially orthogonal to the sensor axis. The diaphragm extends through the cavity and defines a measurement chamber and an input chamber of the cavity. Further, at least a portion of the diaphragm disposed in the cavity defines a first electrode plate. The assembly further includes a second electrode plate disposed on or at least partially within the first surface of the sensor housing along the sensor axis, where the second electrode plate is substantially parallel to the first electrode plate; and a passageway that extends between an inlet disposed in the side surface of the sensor housing and the input chamber and that is configured to transfer ambient pressure to the diaphragm. The first electrode plate and the second electrode plate form a variable capacitor disposed along the sensor axis.

[0008] In another example, aspects of this disclosure relate to a method including disposing a recess in an inner surface of a sensor substrate along a sensor axis that is substantially orthogonal to the inner surface of the sensor substrate; disposing a second electrode plate on or at least partially within an outer surface of the sensor substrate along the sensor axis; and disposing a diaphragm on or at least partially within the inner surface of the sensor substrate and over the recess to define a measurement chamber between the diaphragm and the recess. At least a portion of the diaphragm disposed over the recess defines a first electrode plate, a first major surface of the diaphragm is substantially orthogonal to the sensor axis, and the second electrode plate is substantially parallel to and spaced apart from the diaphragm. The method further includes disposing a recess in an inner surface of a cover; connecting the inner surface of the cover to the inner surface of the sensor substrate such that the diaphragm is disposed between the sensor substrate and the cover, where the sensor substrate and the cover provide a sensor housing, where the outer surface of the sensor substrate defines a first surface of the sensor housing and an outer surface of the cover defines a second surface of the sensor housing, and furtherwhere the recess of the cover and the diaphragm define an input chamber; and disposing a passageway between the sensor substrate and the cover. The passageway extends between an inlet disposed in a side surface of the sensor housing and the input chamber. The side surface extends between the first and second surfaces of the sensor housing. The first electrode plate and the second electrode plate form a variable capacitor disposed along the sensor axis. Further, the sensor substrate, cover, and variable capacitor form a pressure sensor assembly.

[0009] In another example, aspects of this disclosure relate to a pressure sensor assembly extending along a sensor axis, the pressure sensor assembly including a sensor housing. The sensor housing includes a first surface substantially orthogonal to the sensor axis, a second surface substantially parallel to the first surface, and a side surface that extends between the first and second surfaces. The sensor housing further includes a sensor substrate and a cover connected to the sensor substrate. An outer surface of the sensor substrate defines the first surface of the sensor housing and an outer surface of the cover defines the second surface of the sensor housing. Further, an inner surface of the sensor substrate faces an inner surface of the cover. The assembly further includes a cavity disposed within the sensor housing along the sensor axis; a diaphragm disposed within the sensor housing along the sensor axis and including a first major surface and a second major surface, where the first major surface is substantially orthogonal to the sensor axis, where the diaphragm extends through the cavity and defines a measurement chamber and an input chamber of the cavity, and where at least a portion of the diaphragm disposed in the cavity defines a first electrode plate; and a second electrode plate disposed on or at least partially within a region of the sensor substrate of the sensor housing along the sensor axis, where the second electrode plate is substantially parallel to the first electrode plate. The assembly further includes a passageway that extends between an inlet disposed in the side surface of the sensor housing and the input chamber and is configured to transfer ambient pressure to the diaphragm. The first electrode plate and the second electrode plate form a variable capacitor disposed along the sensor axis.

[0010] All headings provided herein are for the convenience of the reader and should not be used to limit the meaning of any text that follows the heading, unless so specified.

[0011] The terms “comprises” and variations thereof do not have a limiting meaning where these terms appear in the description and claims. Such terms will be understoodto imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements. The term “consisting of’ means “including,” and is limited to whatever follows the phrase “consisting of.” Thus, the phrase “consisting of’ indicates that the listed elements are required or mandatory and that no other elements may be present. The term “consisting essentially of’ means including any elements listed after the phrase and is limited to other elements that do not interfere with or contribute to the activity or action specified in the disclosure for the listed elements. Thus, the phrase “consisting essentially of’ indicates that the listed elements are required or mandatory, but that other elements are optional and may or may not be present depending upon whether or not they materially affect the activity or action of the listed elements.

[0012] The words “preferred” and “preferably” refer to embodiments of the disclosure that may afford certain benefits, under certain circumstances; however, other embodiments may also be preferred, under the same or other circumstances.Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the disclosure.

[0013] In this application, terms such as “a,” “an,” and “the” are not intended to refer to only a singular entity but include the general class of which a specific example may be used for illustration. The terms “a,” “an,” and “the” are used interchangeably with the term “at least one.” The phrases “at least one of’ and “comprises at least one of’ followed by a list refers to any one of the items in the list and any combination of two or more items in the list.

[0014] As used herein, the term “or” is generally employed in its usual sense including “and / or” unless the content clearly dictates otherwise.

[0015] The term “and / or” means one or all of the listed elements or a combination of any two or more of the listed elements.

[0016] As used herein in connection with a measured quantity, the term “about” refers to that variation in the measured quantity as would be expected by the skilled artisan making the measurement and exercising a level of care commensurate with the objective of the measurement and the precision of the measuring equipment used.Herein, “up to” a number (e.g., up to 50) includes the number (e.g., 50).

[0017] Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range as well as the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0018] The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 is a schematic view of one embodiment of an implantable medical device disposed within a body of a patient.

[0020] FIG. 2 is a schematic perspective view of the implantable medical device of FIG.1.

[0021] FIG. 3 is a schematic block diagram view of the implantable medical device of FIG. 1.

[0022] FIG. 4 is s schematic cross-section view of a pressure sensor assembly of the implantable medical device of FIG. 1.

[0023] FIG. 5 is a schematic side view of the pressure sensor assembly of FIG. 4.

[0024] FIG. 6 is a schematic top plan view of a first surface of the pressure sensor assembly of FIG. 4.

[0025] FIG. 7 is a schematic bottom plan view of a sensor substrate of the pressure sensor assembly of FIG. 4.

[0026] FIG. 8 is a schematic perspective view of a cover of the pressure sensor assembly of FIG. 4.

[0027] FIG. 9 is a schematic top plan view of the cover of the pressure sensor assembly of FIG. 4.

[0028] FIG. 10 is a schematic bottom plan view of the cover of the pressure sensor assembly of FIG. 4.

[0029] FIG. 11 is a schematic side view of another pressure sensor assembly that can be utilized with the implantable medical device of FIG. 1.

[0030] FIG. 12 is a schematic top plan view of a cover of the pressure sensor assembly of FIG. 11.

[0031] FIG. 13 is a schematic side view of another pressure sensor assembly that can be utilized with the implantable medical device of FIG. 1.

[0032] FIG. 14 is a flowchart of one method of forming the pressure sensor assembly and implantable medical device of FIG. 1.

[0033] FIG. 15 is a schematic cross-section view of another embodiment of a pressure sensor assembly that can be utilized with the implantable medical device of FIG. 1.

[0034] FIG. 16 is a schematic cross-section view of a portion of the pressure sensor assembly of FIG. 15.

[0035] FIG. 17 is a schematic perspective view of a diaphragm and first electrode plate of a variable capacitor of the pressure sensor assembly of FIG. 15.

[0036] FIG. 18 is a schematic plan view of the diaphragm and first electrode plate of FIG. 17.

[0037] FIG. 19 is a schematic plan view of an out surface of a sensor substrate of a sensor housing of the pressure sensor assembly of FIG. 15.

[0038] FIG. 20 is a schematic plan view of an inner surface of the sensor substrate of FIG. 19.

[0039] FIG. 21 is a schematic cross-section view of another embodiment of an implantable medical device that includes the pressure sensor assembly of FIG. 15.DETAILED DESCRIPTION

[0040] The techniques of this disclosure generally relate to a pressure sensor assembly and implantable medical device (IMD) that includes such assembly. The assembly can include a diaphragm disposed within a cavity of a sensor housing such that the diaphragm extends through the cavity and defines a measurement chamber and an input chamber of the cavity. The diaphragm also provides or defines a first electrode plate, and a second electrode plate can be disposed on or at least partially within a surface of the sensor housing along a sensor axis, where the second electrode plate is substantially parallel to the first electrode plate. The first and second electrode plates provide a variable capacitor that is disposed along the sensor axis. One or more passageways can each extend between an inlet disposed in a side surface of the sensor housing and the input chamber, where eachpassageway is configured to transfer ambient pressure from an atmosphere adjacent to the pressure sensor assembly to the diaphragm. In one or more embodiments, the variable capacitor of the assembly can be configured to provide a first capacitance reading based upon a distance between the first electrode plate and the second electrode plate as such distance changes due to deflection of the diaphragm caused by pressure changes in the input chamber in response to ambient pressure changes. The first capacitance reading can be compared to a second capacitance reading provided by a reference capacitor of the assembly to determine a pressure change of the environment adjacent to the assembly using any suitable technique.

[0041] Low power pressure sensors such as capacitive pressure sensors can be utilized with IMDs. Pressure sensors having smaller form factors may be needed for some IMDs. Such sensors are typically disposed on or at least partially within a housing of the IMD such that a diaphragm of the sensor is at or adjacent to an outer surface of the housing to receive ambient pressure from an environment or atmosphere adjacent the device. The sensor, therefore, may occupy limited surface space of the housing and prevent other elements such as electrodes or fixation elements from being disposed on or at least partially within the housing.

[0042] One or more embodiments of pressure sensor assemblies and IMDs including such assemblies described herein can exhibit various advantages over currently-available assemblies and IMDs. For example, a variable capacitor of the pressure sensor assembly can be disposed within a housing of the IMD and not on a surface of the IMD housing, thereby leaving additional space for placement, e.g., of one or more electrodes or and / or fixation elements at a first end of the housing and one or more delivery system elements at a second end of the housing. The diaphragm of the pressure sensor assembly can be protected from damage during handling, implantation, and operation as it is disposed within the device housing. As a result, the diaphragm may be less affected by tissue overgrowth when disposed within the device housing as opposed to devices where the diaphragm is disposed at or adjacent to an outer surface of the housing. In addition, disposing the diaphragm such that it is within the device housing and perpendicular to a device axis can allow for a larger area of a deflecting surface of the diaphragm without compromising a curved outer surface of the device housing if the diaphragm were to bedisposed at or adjacent to the outer surface. Efficiencies in packaging can also be realized by disposing the diaphragm within the device housing of the IMD.

[0043] FIG. l is a schematic view of one embodiment of an implantable medical device 12 (IMD) disposed within a body of a patient 2. The IMD 12 can include any suitable medical device, e.g., a pacing device, pressure sensing device, cardiac monitor, other physiologic sensor, etc. The IMD 12 can include a pressure sensor assembly as is further described herein. IMD 12 can be, for example, an implantable leadless pacing device that is configured for implantation entirely within one of the chambers of a heart 4 and that provides electrical signals to the heart beneath a sternum 3 via electrodes carried on the device housing of the pacing device.

[0044] IMD 12 is generally described as being attached within a chamber of the heart 4 as an intracardiac pacing device. In one or more embodiments, IMD 12 can be attached to an external surface of the heart 4 such that the device is disposed outside of the heart but can pace a desired chamber. In one or more embodiments, IMD 12 is attached to an external surface of the heart 4, and one or more components of the device can be in contact with an epicardium of the heart. The IMD 12 is schematically shown in FIG. 1 attached to a wall of a ventricle of the heart 4 via one or more fixation elements (e.g., tines, helix, etc.) that penetrate the tissue. These fixation elements can secure the IMD 12 to the cardiac tissue and retain an electrode (e.g., a cathode or an anode) in contact with the cardiac tissue.IMD 12 can be implanted at or proximate to the apex of the heart. In one or more embodiments, a pacing device may be implanted at other ventricular locations, e.g., on the free-wall or septum, an atrial location, or any location on or within the heart 4.

[0045] FIG. 2 is a schematic side view of the IMD 12 of FIG. 1. In one or more embodiments, the IMD 12 is configured to be implanted within a chamber of the heart 4 of the patient 2, e.g., to monitor electrical activity of the heart and / or provide electrical therapy to the heart. In the example shown in FIG. 2, the IMD 12 includes a device housing 14, fixation elements 16, and electrodes 18 and 20.

[0046] The device housing 14 of the IMD 12 can include any suitable dimensions and take any suitable shape. The device housing 14 extends between a first end 6 and a second end 8 along a longitudinal axis 10. In one or more embodiments, the device housing 14 can have a cylindrical (e.g., pill-shaped) form factor. In one or more embodiments, the device housing 14 includes an elongated tubular housing. Further, the device housing 14 caninclude any suitable material, e.g., at least one of an inorganic material (e.g., metallic, ceramic) or an organic material (e.g., polymeric).

[0047] The IMD 12 can include a fixation mechanism configured to fix pacing device 12 to tissue within the body of the patient 2. For example, in the embodiment illustrated in FIG. 2, the IMD 12 includes one or more fixation elements (e.g., tines) 16 extending from the device housing 14 that are configured to engage with tissue to substantially fix a position of the device housing within the patient 2. In one or more embodiments, the fixation elements 16 are configured to anchor housing 14 to the cardiac tissue such that the IMD 12 moves along with the cardiac tissue during cardiac contractions. Fixation elements 16 can include any suitable material, e.g., a shape memory material (e.g., Nitinol). Although the IMD 12 includes one or more fixation elements 16 that are configured to anchor the device to tissue, in one or more embodiments, the device can be fixed to tissue using other types of fixation mechanisms, such as, but not limited to, barbs, coils, and the like.

[0048] Housing 14, also referred to as an elongated housing, houses electronic components of the IMD 12, e.g., sensing circuitry for sensing electrical activity via electrodes 18 and 20 and therapy generation circuitry for delivering electrical stimulation therapy via the electrodes. Electronic components can include any discrete and / or integrated electronic circuit components that implement analog and / or digital circuits capable of producing the functions attributed to the IMD 12. In one or more embodiments, housing 14 can also house components for sensing other physiological parameters, such as acceleration, pressure, sound, and / or impedance. For example, IMD 12 includes a pressure sensor assembly 36 as is further described herein. Although shown with two electrodes 18 and 20, the device 12 can include any suitable number of electrodes disposed in any suitable portion or portions of the device housing 14.

[0049] Additionally, the device housing 14 can also house a memory that includes instructions that, when executed by processing circuitry housed within housing, cause the IMD 12 to perform various functions attributed to the device herein. In one or more embodiments, the device housing 14 can house communication circuitry that enables the IMD 12 to communicate with other electronic devices, such as a medical device programmer. In one or more embodiments, the device housing 14 can also house an antenna for wireless communication. The device housing 14 can also house a powersource, such as a battery. The device housing 14 can be hermetically or near-hermetically sealed using any suitable technique to help prevent fluid ingress into the housing. For example, in one or more embodiments, one or more portions of the device housing 14 can be hermetically sealed together utilizing one or more laser diffusion bonding techniques described in co-owned U.S. Patent No. 10,124,559 B2, entitled KINETICALLY LIMITED NANO-SCALE DIFFUSION BOND STRUCTURES AND METHODS.

[0050] The IMD 12 include the electrodes 18, 20 that can be connected to the device housing utilizing any suitable technique. In one or more embodiment, at least one of the electrodes 18, 20 can be mechanically connected to housing 14. In one or more embodiments, at least one of the electrodes 18, 20 can be defined by an outer portion of the device housing 14 that is electrically conductive. For example, electrode 20 can be defined by a tissue-exposed conductive portion of housing 14.

[0051] Electrodes 18, 20 are electrically isolated from each other. Electrode 18 can be referred to as a tip electrode, and fixation elements 16 can be configured to anchor the IMD 12 to tissue such that electrode maintains contact with the tissue. In one or more embodiments, fixation elements 16 can also be electrically connected to one or more electronic components such that the elements are configured to direct an electrical signal to tissue of the patient and / or receive an electronic signal from the tissue. In one or more embodiments, a portion of the housing 14 can be covered by, or formed from, an insulative material to isolate electrodes 18 and 20 from each other and / or to provide a desired size and shape for one or both of electrodes.

[0052] Electrode 20 can be a portion of housing 14, e.g., second portion 24, that does not include such insulative material. Electrode 20 can be most or all of housing 14, but most of the device housing (other than electrode 20) can be covered with an insulative coating. In one or more embodiments, electrode 20 may be coated with materials to promote conduction. In one or more embodiments, electrode 20 can be part of a separate ring portion of housing 14 that is conductive. Electrodes 18, 20, which may include conductive portion(s) of a first portion 22 of the housing 14 and / or a second portion 24 of the housing, can be electrically connected to at least some electronics of pacing device 12 (e.g., sensing circuitry, electrical stimulation circuitry, or both). In one or more embodiments, the device housing 14 can include an end cap 26, which can house or enclose a feedthrough header assembly (e.g., feedthrough header assembly 42 of FIG. 3) to electrically connect theelectrode 18 to the electronics within the device housing 14, while electrically isolating the electrode from the device housing 14, e.g., including electrode 20 or other conductive portions of the device housing.

[0053] In the embodiment illustrated in FIG. 2, the device housing 14 includes the first portion 22 and the second portion 24. The first portion 22 can be disposed adjacent to the first end 6 of the device housing 14, and the second portion 24 can be disposed adjacent to the second end 8 of the device housing. The second portion 24 can, in one or more embodiments, define at least part of a power source case that houses a power source (e.g., a battery) of the IMD 12. In one or more embodiments, the second portion 24 can include the conductive portion of the device housing 14 that forms the electrode 20. Further, at least one of the first portion 22 or the second portion 24 can include the pressure sensor assembly 36, which can form one or more portions of the device housing 14. The first portion 22 of the device housing 14 can be connected to the second portion 24 of the device housing using any suitable technique.

[0054] In the embodiment of FIG. 2, the IMD 12 can also include a flange 28 connected to the second portion 24 of the device housing 14 at the second end 8 of the device housing that defines an opening. The flange 28 can enable medical instruments to attach to the IMD 12, e.g., for delivery and / or extraction of the device. For example, a tether that extends through a catheter inserted into the heart 4 (FIG. 1) can be attached to the flange 28 and / or threaded through the opening to implant or extract the IMD 12.

[0055] FIG. 3 is a schematic block diagram of one embodiment of the IMD 12 including a power source 30 (e.g., battery), an electronics module 32, an electrical contact assembly 34, and the pressure sensor assembly 36. Although the IMD of FIG. 3 is described as IMD 12, the structures shown in FIG. 3 can also be used in other implantable or external medical devices, such as cardioverter-defibrillators, physiological monitors, or neurostimulators, or any other electronic devices. The power source 30 can be electrically connected to the electronics module 32 and the pressure sensor assembly 36 using any suitable technique.

[0056] The device housing 14 includes the first and second portions 22, 24 and the pressure sensor assembly 36 disposed within the device housing between the battery 30 and the electrical contact assembly 34. The assembly 36 can be disposed in any suitable portion or portions of the housing 14. For example, the pressure sensor assembly 36 can bedisposed within at least one of the first and second housing portions 22, 24 or at the boundary of the first and second housing portions. As shown in FIG. 3, the pressure sensor assembly 36 is disposed between the electronics module 32 and the power source 30.

[0057] In one or more embodiments, the first and second housing portions 22, 24 are common with a ground terminal of power source 30. In one or more embodiments, one or both of the first and second housing portions 22, 24 is non-conductive. For example, first housing portion 22 can be formed of a non-conductive material, such as sapphire, which may allow easier transmission of electromagnetic signals into and out of the device housing 14 than a metal or other conductive material would allow.

[0058] As shown in the embodiment illustrated in FIG. 3, the pressure sensor assembly 36 extends across housing 14 between the power source 30 on one side and electrical contact assembly 34 on the other side. The assembly 36 can include at least one feedthrough (feedthrough 100 of FIG. 4) to allow for electrical connection between the power source 30 and the electronics module 32. Feedthrough header assembly 42 can also include at least one feedthrough to allow for an electrical connection between electrode 18 and electronic layers 40. Electronics module 32 is disposed between the electrode 18 and electrical contact assembly 34. In one or more embodiments, electrical contact assembly 34 can be fixed to pressure sensor assembly 36 or a sidewall (not shown) to provide mechanical support for the electronics module 32. The electrical contact assembly 34 provides an electrical connection between the pressure sensor assembly 36 and the power source 30, and the electronics module 32. For example, the electronics module 32 can include one or more electrical contacts that are configured to electrically connect the module to the electrical contact assembly 34.

[0059] The IMD 12 can also include a battery header 38 disposed between the power source 30 and the electrical contact assembly 34. The pressure sensor assembly 36 can form part or all of the battery header 38. In one or more embodiments, the assembly 36 defines the battery header 38. The battery header 38, the assembly 36, and the electrical contact assembly 34 can be electrically connected to the electronics module 32 using any suitable technique. In one or more embodiments, at least one of the battery header 38, the assembly 36, or the electrical contact assembly 34 can include feedthroughs and / or openings for creating an electrical connection between the power source 30 and electronics module 32.

[0060] The electrical contact assembly 34 can include any suitable assembly for electrically connecting the electronics module 32 with the pressure sensor assembly 36 and the power source 30, e.g., one or more embodiments of electrical contact assemblies described in co-owned U.S. Patent Application Publication No. 2021 / 0121705 Al, entitled ELECTRONICS ASSEMBLY FOR IMPLANTABLE MEDICAL DEVICE. In one or more embodiments, the electrical contact assembly 34 can include a spring contact for holding electronics module 32 in place and for providing electrical connections between the electronics module and the pressure sensor assembly 36.

[0061] The electronics module 32 can include any suitable electronics module or modules, e.g., one or more embodiments of electronics modules described in U.S. Patent No.11,633,611 B2, entitled FEEDTHROUGH ASSEMBLY AND DEVICE INCLUDING SAME; U.S. Patent Publication No. 2023 / 0248982 Al, entitled FEEDTHROUGH ASSEMBLY AND IMPLANTABLE MEDICAL DEVICE INCLUDING SAME; and U.S. Patent Publication No. 2022 / 0241598 Al, entitled FEEDTHROUGH HEADER ASSEMBLY AND DEVICE INCLUDING SAME. For example, as shown in FIG. 3, the electronics module 32 includes one or more electronic layers 40 and the feedthrough header assembly 42 electrically connected to the one or more electronic layers 40. The electronics module 32 can also include one or more coils 44 electrically connected to the electronic layers 40.

[0062] The IMD 12 can include any suitable pressure sensor assembly 36. As illustrated in FIGS. 4-10, the assembly 36 includes a sensor housing 46 having a first surface 48, a second surface 50 substantially parallel to the first surface, and a side surface 52 that extends between the first and second surfaces and connects the first and second surfaces. A cavity 54 is disposed within the sensor housing 46 along a sensor axis 56 that is substantially orthogonal to the first surface 48. In one or more embodiments, the sensor axis 56 is substantially parallel to the longitudinal axis 10 of the IMD 12. As used herein, the phrase “substantially parallel” means that an angle formed between the longitudinal axis 10 and the sensor axis 56 is no greater than 10 degrees. Further, a diaphragm 58 is disposed within the sensor housing 46 along the sensor axis 56 and includes a first major surface 60 and a second major surface 62, where the first major surface is substantially orthogonal to the sensor axis, and where the diaphragm extends through the cavity 54 and defines a measurement chamber 64 and an input chamber 66 of the cavity. At least aportion of the diaphragm 58 is disposed in the cavity 54 and defines a first electrode plate 68. A second electrode plate 70 is disposed on or at least partially within the first surface 48 of the sensor housing 46 along the sensor axis 56, where the second electrode plate is substantially parallel to the first electrode plate 68. The assembly 36 also includes a passageway 72 (FIG. 5) that extends between an inlet 74 disposed in the side surface 52 of the sensor housing 46 and the input chamber 66 and that is configured to transfer ambient pressure to the diaphragm 58. The first electrode plate 68 and the second electrode plate 70 form a variable capacitor 76 disposed along the sensor axis 56.

[0063] The pressure sensor assembly 36 can be electrically connected to one or more electronic components disposed on or within the IMD 12. In one or more embodiments, the pressure sensor assembly 36 can be electrically connected to the electronics module 32 using any suitable technique. In one or more embodiments, the pressure sensor assembly 36 can be electrically connected to one or more electronic components (e.g., a controller) of electronic layers 40 of the electronics module 32 using any suitable technique, e.g., via electrical contact assembly 34. The one or more electronic components electrically connected to the pressure sensor assembly 36 can be utilized to determine a pressure signal provided by the pressure sensor assembly 36 and a reference signal provided by one or more reference capacitors 96 as is further described herein.

[0064] The pressure sensor assembly 36 can take any suitable shape and have any suitable dimensions. In one or more embodiments, the sensor housing 46 can take an elliptical shape in a plane orthogonal to the sensor axis 56. Further, the cavity 54 can take any suitable shape and having any suitable dimensions.

[0065] Although depicted as being utilized with the IMD 12, the pressure sensor assembly 36 can be utilized with any suitable device or system. The pressure sensor assembly 36 can be disposed in any suitable portion or portions of the device housing 14 of the IMD 12. In one or more embodiments, the assembly 36 can be disposed entirely within housing 14 of IMD 12. In one or more embodiments, the assembly 36 can define one or more portions of the device housing 14 of the IMD 12. In such embodiments, the device housing 14 and the pressure sensor assembly 36 enclose the electronics module 32 and the power source 30.

[0066] Further, the sensor housing 46 can include any suitable material, e.g., at least one of an inorganic (e.g., metallic or ceramic) or organic (e.g., polymeric) material. In one or more embodiments, the sensor housing 46 includes titanium.

[0067] The sensor housing 46 can be a unitary housing, e.g., formed as a single piece or part during manufacturing, and the cavity 54 can be disposed within the device housing using any suitable technique. In one or more embodiments, the sensor housing 46 can include two or more pieces or parts that are connected using any suitable technique.

[0068] For example, as shown in FIG. 4, the sensor housing 46 can include a sensor substrate 78 and a cover 80 connected to the sensor substrate using any suitable technique, e.g., welding, laser welding, adhering, mechanically fastening, thermocompression bonding, etc. An outer surface 82 of the sensor substrate 78 defines the first surface 48 of the sensor housing 46, and an outer surface 84 of the cover 80 defines the second surface 50 of the device housing. Further, an inner surface 86 of the sensor substrate 78 faces an inner surface 88 of the cover 80.

[0069] Each of the sensor substrate 78 and the cover 80 can include any suitable material, e.g., the same material described herein regarding the sensor housing 46. In one or more embodiments, at least one of the sensor substrate 78 or the cover 80 can include sapphire. The sensor substrate 78 and the cover 80 can include the same material or different materials. Further, the sensor substrate 78 and the cover 80 can take any suitable shape and have any suitable dimensions.

[0070] The sensor substrate 78 can include a recess 90 disposed in the inner surface 86 of the sensor substrate, and the cover 80 can include a recess 92 disposed in the inner surface 88 of the cover. The cavity 54 of the sensor housing 46 can be defined by the recess 90 of the sensor substrate 78 and the recess 92 of the cover 80.

[0071] Disposed within the sensor housing 46 along the sensor axis 56 is the diaphragm 58, which includes the first major surface 60 and the second major surface 62. The first major surface 60 is substantially orthogonal to the sensor axis 56. As used herein, the phrase “substantially orthogonal” means that an angle defined between the first major surface of the diaphragm 58 and the sensor axis 56 is at least 80 degrees and no greater than 100 degrees. The diaphragm 58 extends through the cavity 54 and defines the measurement chamber 64 and the input chamber 66 of the cavity. At least a portion of the diaphragm 58 disposed in the cavity 54 defines the first electrode plate 68.

[0072] The diaphragm 58 can take any suitable shape. For example, the diaphragm 58 can take an elliptical shape in a plane substantially orthogonal to the sensor axis 56. Further, the diaphragm 58 can have any suitable dimensions. For example, the diaphragm 58 can have a thickness in a direction parallel to the sensor axis 56 that is at least about 1 micron and no greater than about 100 microns. The diaphragm 58 can include any suitable material, e.g., at least one of an inorganic (e.g., metallic or ceramic) or organic (e.g., polymeric) material. In one or more embodiments, the diaphragm 58 can include titanium. Further, in one or more embodiments, the sensor housing 46 and the diaphragm 58 can include titanium.

[0073] In embodiments where the sensor housing 46 is provided by the sensor substrate 78 and the cover 80, the first major surface 60 of the diaphragm 58 can face the recess 90 disposed in the inner surface 86 of the sensor substrate, and the second major surface 62 of the diaphragm can face the recess 92 disposed in the inner surface 88 of the cover. The diaphragm 58 can be disposed on or at least partially within the inner surface 86 of the sensor substrate 78. In one or more embodiments, the diaphragm 58 can be disposed entirely within the inner surface 86 of the sensor substrate 78.

[0074] The diaphragm 58 can be disposed in the sensor housing 46 such that at least a portion of the diaphragm is free to move in response to ambient pressure that is transferred to it by the passageway 72. In one or more embodiments, an edge 94 of the diaphragm 58 can be fixed or connected to at least one of the sensor substrate 78 or cover 80 using any suitable technique, e.g., welding, bonding, adhering, mechanically fastening, etc. In one or more embodiments, the edge 94 of the diaphragm 58 is fixed between the sensor substrate 78 and the cover 80 so that the portion of the diaphragm that defines the first electrode plate 68 can move in response to ambient pressure.

[0075] The first electrode plate 68 can be defined by the diaphragm 58 using any suitable technique. In one or more embodiments, the diaphragm 58 includes a conductive material such that the diaphragm defines the first electrode plate 68. In one or more embodiments, a conductive material can be disposed on the first major surface 60 of the diaphragm 58 to provide the first electrode plate 68.

[0076] The diaphragm 58 can be electrically connected to one or more electronic components disposed on or within the sensor housing 46 to in part form the variable capacitor 76. In one or more embodiments, the diaphragm 58 is electrically connected tothe sensor housing 46 using any suitable technique. In one or more embodiments, the diaphragm 58 is electrically connected to one or more electronic components of electronic layers 40 of electronics module 32.

[0077] The diaphragm 58 extends through the cavity 54 and defines the measurement chamber 64 and the input chamber 66 of the cavity. The measurement chamber 64 can take any suitable shape and have any suitable dimensions. In one or more embodiments, the measurement chamber 64 is hermetically sealed using any suitable technique. Such hermetically-sealed space can prevent contaminants from entering the measurement chamber 64 and interfering with the function of the variable capacitor 76. In one or more embodiments, the measurement chamber 64 can be filled with any suitable dielectric material, e.g., gas, gel, or solid material. The dielectric material can include at least one of e.g., air, nitrogen, helium, argon, or vacuum. In one or more embodiments, the dielectric material includes a compressible material.

[0078] The input chamber 66 can also take any suitable shape and have any suitable dimensions. In one or more embodiments, the input chamber 66 is connected to an atmosphere or environment external to the pressure sensor assembly 36 by the passageway 72, which is configured to transfer ambient pressure from this external atmosphere to the diaphragm 58.

[0079] The pressure sensor assembly 36 can also include the second electrode plate 70 that is disposed on or at least partially within the first surface 48 of the sensor housing 46 along the sensor axis 56. The second electrode plate 70 is substantially parallel to the first electrode plate 68 and spaced apart from the first electrode plate any suitable distance. The first electrode plate 68 and the second electrode plate 70 form the variable capacitor 76 that is disposed along the sensor axis 56.

[0080] The second electrode plate 70 can be disposed on or at least partially within the first surface 48 of the sensor housing 46 using any suitable technique. In one or more embodiments, an opening 98 (FIG. 7) can be disposed through the first surface 48 of the sensor housing 46 to the cavity 54. The second electrode plate 70 can be disposed at least partially within the opening 98 and electrically isolated from the sensor housing by a dielectric material 71 disposed between the device housing and the second electrode plate. The second electrode plate 70 can be electrically connected to one or more electronic components disposed on or within the sensor housing 46 or disposed elsewhere on orwithin the device housing 14 of the IMD 12 (e.g., one or more electronic components of electronic layers 40) using any suitable technique. In one or more embodiments, the second electrode plate 70 is formed in the sensor housing 46 and extends between the first surface 48 of the sensor housing 46 and the cavity 54.

[0081] The pressure sensor assembly 36 also includes one or more passageways 72 each extending between the inlet 74 disposed in and defined by the side surface 52 of the sensor housing 46 and the input chamber 66. At least one passageway 72 is configured to transfer ambient pressure to the diaphragm 58. The assembly 36 can include any suitable number of passageways 72. In one or more embodiments, the assembly 36 can include a plurality of passageways 72 each extending between an inlet 74 disposed in the side surface 52 of the sensor housing 46 and the input chamber 66.

[0082] Further, each passageway 72 can take any suitable shape and have any suitable dimensions. The passageway 72 can be disposed in any suitable portion or portions of the assembly 36. In one or more embodiments, the passageway 72 can be disposed between the sensor substrate 78 and the cover 80.

[0083] Further, the inlet 74 of each passageway 72 can take any suitable shape and have any suitable dimensions. As shown in FIG. 5, each inlet 74 takes a rectangular shape.

[0084] As mentioned herein, the pressure sensor assembly 36 can have any suitable number of passageways 72. For example, FIG. 11 is a schematic side view of another embodiment of a pressure sensor assembly 236 that can be utilized with the IMD 12 of FIG. 1. All design considerations and possibilities described herein regarding pressure sensor assembly 36 of FIGS. 2-10 apply equally to pressure sensor assembly 236 of FIG. 11 unless stated otherwise.

[0085] One difference between pressure sensor assembly 236 and assembly 36 is that assembly 236 includes a single passageway 272 that extends between an inlet 274 disposed in a side surface 252 of a sensor housing 246 and an input chamber 266 disposed inside the sensor housing, where the passageway is configured to transfer ambient pressure to a diaphragm (not shown) disposed within the sensor housing. The inlet 274 extends along a substantial portion of the side surface 252 of the sensor housing 246. As shown in FIG. 12, which is a schematic top plan view of a cover 280 of the sensor housing 246 of the pressure sensor assembly 236 of FIG. 11, the inlet 274 of the passageway 272 has anarc length 202 of any suitable value, e.g., at least 0.01 radians and no greater than pi radians.

[0086] As mentioned herein, the passageway 72 of pressure sensor assembly 36 of FIGS. 2-10 can have any suitable dimensions. For example, FIG. 13 is a schematic side view of another pressure sensor assembly 336 that can be utilized with the implantable medical device 12 of FIG. 1. All design considerations and possibilities described herein regarding the pressure sensor assembly 36 of FIGS. 2-10 and pressure sensor assembly 236 of FIGS. 11-12 apply equally to the pressure sensor assembly 336 of FIG. 13 unless stated otherwise. As shown in FIG. 13, the assembly 336 includes a sensor housing 346 having a sensor substrate 378 and a cover 380 connected to the sensor substrate by two or more standoffs or posts 302 that each extends between an inner surface 386 of the sensor substrate and an inner surface 388 of the cover. The assembly 336 can include any suitable number of standoffs 302 having any suitable dimensions. Further, each standoff 302 can take any suitable shape. The standoffs 302 can be disposed in any suitable location between the sensor substrate 378 and the cover 380. In essence, connection of the sensor substrate 378 and the cover 380 utilizing the standoffs 302 provides multiple passageways 372 from an atmosphere external to the assembly 336 to an input chamber (not shown) disposed within the housing 346 of the assembly.

[0087] Returning to FIGS. 2-10, each of the passageways 72 of assembly 36 can be formed or disposed within the sensor housing 46 using any suitable technique. In one or more embodiments, the sensor substrate 78 and the cover 80 can be connected utilizing at least two standoffs (e.g., standoff 302 of assembly 336 of FIG. 13) that extend between the inner surface 86 of the sensor substrate 78 and the inner surface 88 of the cover 80. As shown in FIG. 8, one or more channels 73 can be disposed in the inner surface 88 of the cover 80 using any suitable technique such that the channels extend from an outer perimeter 51 of the cover 80 to the recess 92 disposed in the inner surface 88 of the cover. As mentioned herein, the recess 92 of the cover 80 and the diaphragm 58 define the input chamber 66. The channel 73 can take any suitable shape and have any suitable dimensions. The channels 73 along with the inner surface 86 of the sensor substrate 78 form passageways 72 when the sensor substrate is connected to the cover.

[0088] In one or more embodiments, a material (not shown) can be disposed at least partially within one or more of the passageways 72 to prevent ingress of body fluids ortissue into the passageway. In one or more embodiments, such material can be a polymeric material, e.g., at least one of a fluid, gel (e.g., hydrogel), or soft elastomer (e.g., silicone). In one or more embodiments, the material disposed within the passageways 72 can be compliant such that it transmits pressure forces from exterior to the assembly 36 to the diaphragm 58. The material can be disposed within one or more passageways 72 using any suitable technique.

[0089] In general, one or more embodiments of pressure sensor assemblies described herein can include one or more electronic components disposed on or at least partially within a housing of such assembly. As shown in FIG. 4, the assembly 36 includes a reference capacitor 96 disposed on or at least partially within the first surface 48 of the sensor housing 46. In one or more embodiments, the reference capacitor 96 can be disposed on the second surface 50 of the sensor housing 46. Further, in one or more embodiments, the reference capacitor 96 can be disposed on or at least partially within one or more of the electronic layers 40 of the IMD. Regardless of its position within the IMD 12, reference capacitor 96 can be electrically connected to one or more electronic components of the electronic layers 40 (e.g., a controller) using any suitable technique. Although depicted as including one reference capacitor 96, the assembly 36 can include any suitable number reference capacitors.

[0090] The variable capacitor 76 of assembly 36 can be configured to detect changes in pressure of an environment adjacent to the side surface 52 of the sensor housing 46 of the assembly 36 through deflection of the diaphragm 58 caused by these changes. For example, the variable capacitor 76 can be electrically connected to a controller 97 disposed in any suitable location on or within the IMD 12 or external to the IMD, e.g., on or at least partially within one or more of the electronic layers 40 of the electronics module 32. Such controller 97 can include any suitable electronic circuitry or components, e.g., one or more processors, memory, input devices, output devices, sensors, power sources, etc. Further, the controller can include any suitable memory or storage.

[0091] The controller 97 can be adapted to detect a first capacitance of the variable capacitor 76 of the pressure sensor assembly 36, detect a second capacitance of the reference capacitor 96 of the assembly (or other reference capacitors disposed within the IMD 12), and compare the first capacitance and the second capacitance. Such comparison can utilize any suitable technique to determine whether a pressure of the externalenvironment has changed and if so to what extent. The comparison can provide a pressure change value that can be transmitted by a transceiver to an external transceiver using any suitable technique. In one or more embodiments, the controller 97 can be adapted to determine at least one of an average pressure, dynamic time-varying pressure, or other suitable pressure value. In one or more embodiments, the pressure change value can be utilized by the IMD 12 to monitor pressure within the heart 4 and / or to make changes to one or more therapies provided to the patient 2.

[0092] In one or more embodiments, the variable capacitor 76 can be configured to provide the first capacitance based upon a distance between the first electrode plate 68 and the second electrode plate 70 as such distance changes due to deflection of the diaphragm 58 caused by pressure changes in the input chamber 66. The first capacitance can be compared to the second capacitance provided by the reference capacitor 96 to determine a pressure change of the environment adjacent to the side surface 52 of the assembly 36 using any suitable technique, e.g., one or more techniques described in U.S. Patent Publication No. 2019 / 0350467 Al to Greenhut and entitled MEASUREMENT OF CARDIAC CYCLE LENGTH AND PRESSURE METRICS FROM PULMONARY ARTERIAL PRESSURE; U.S. Patent No. 7,955,319 B2 to Miesel and entitled PRESSURE SENSING IN IMPLANTABLE MEDICAL DEVICE; and U.S. Patent No. 7,591,185 Bl to Mothilal et al. and entitled PRESSURE SENSOR CONFIGURATIONS FOR IMPLANTABLE MEDICAL ELECTRICAL LEADS.

[0093] The various embodiments of pressure sensor assemblies described herein can also include one or more feedthroughs disposed in any suitable portion or portions of the assembly to provide an electrical pathway through the assembly. For example, as shown in FIG. 4, the pressure sensor assembly 36 includes a feedthrough 100 that includes a via 102 that extends between the first surface 48 and the second surface 50 of the sensor housing 46. A conductive material 104 such as a feedthrough pin can be disposed in the via 102 and extend through the via. A dielectric material 106 can be disposed between the conductive material 104 and the via 102 to electrically isolate the conductive material from the sensor housing 46. The feedthrough 100 can take any suitable shape and have any suitable dimensions. Further, the pressure sensor assembly 36 can include any suitable number of feedthroughs 100.

[0094] FIGS. 15-20 are various view of another embodiment of a pressure sensor assembly 536. All design considerations and possibilities described herein regarding pressure sensor assembly 36 of FIGS. 2-10, pressure sensor assembly 236 of FIGS. 11- 12, and pressure sensor assembly 336 of FIG. 13 apply equally to pressure sensor assembly 536 of FIGS 15-20 unless stated otherwise. The pressure sensor assembly 536 can be utilized with any suitable IMD, e.g., IMD 12 of FIGS. 1-3 or IMD 612 of FIG. 21.

[0095] As illustrated in FIGS. 15-20, the pressure sensor assembly 536 includes a sensor housing 546 having a first surface 548, a second surface 550 substantially parallel to the first surface, and a side surface 552 that extends between the first and second surfaces and connects the first and second surfaces. The sensor housing 546 can further include a sensor substrate 578 and a cover 580 connected to the sensor substrate using any suitable technique, e.g., welding, laser welding, adhering, mechanically fastening, thermocompression bonding, etc. An outer surface 582 of the sensor substrate 578 defines the first surface 548 of the sensor housing 546, and an outer surface 584 of the cover 580 defines the second surface 550 of the device housing. Further, an inner surface 586 of the sensor substrate 578 faces an inner surface 588 of the cover 580.

[0096] The assembly 536 further includes a cavity 554 disposed within the sensor housing 546 along a sensor axis 556 that is substantially orthogonal to the first surface 548. In one or more embodiments, the sensor axis 556 is substantially parallel to longitudinal axis 610 of IMD 612 of FIG. 21 as is further described herein. Further, the assembly 536 also includes a diaphragm 558 disposed within the sensor housing 546 along the sensor axis 556 and includes a first major surface 560 and a second major surface 562, where the first major surface is substantially orthogonal to the sensor axis, and where the diaphragm extends through the cavity 554 and defines a measurement chamber 564 and an input chamber 566 of the cavity. At least a portion of the diaphragm 558 disposed in the cavity 554 defines a first electrode plate 568. A second electrode plate 570 is disposed on or at least partially within a region 585 of the sensor substrate 578 along the sensor axis 556, where the second electrode plate is substantially parallel to the first electrode plate 568. The assembly 536 also includes a passageway 572 (FIG. 15) that extends between an inlet 574 disposed in the side surface 552 of the sensor housing 546 and the input chamber 566 and that is configured to transfer ambient pressure to the diaphragm 558. The firstelectrode plate 568 and the second electrode plate 570 form a variable capacitor 576 disposed along the sensor axis 556.

[0097] Each of the sensor substrate 578 and the cover 580 can include any suitable material, e.g., the same material described herein regarding the sensor housing 546. In one or more embodiments, at least one of the sensor substrate 578 or the cover 580 can include a nonconductive material, e.g., sapphire. In one or more embodiments, the region 585 of the sensor substrate 578 can be integral with the sensor substrate. In one or more embodiments, the region 585 can be formed separately from the sensor substrate 578 and inserted into an opening formed in the sensor substrate using any suitable technique, e.g., the region can be welded to the sensor substrate. The region 585 forms a portion of the sensor substrate 578. In one or more embodiments, the region 585 can be a nonconductive material (e.g., sapphire), and sensor substrate 578 can be a conductive material (e.g., titanium). In one or more embodiments, the second electrode plate 570 can be a conductive layer disposed on the inner surface 586 of the sensor substrate 578 in the region 585 of the sensor substrate. The sensor substrate 578 and the cover 580 can include the same material or different materials. Further, the sensor substrate 578 and the cover 580 can take any suitable shape and have any suitable dimensions.

[0098] Disposed within the sensor housing 546 along the sensor axis 556 is the diaphragm 558, which includes the first major surface 560 and the second major surface 562. The first major surface 560 is substantially orthogonal to the sensor axis 556. As shown in FIG. 21, which is a schematic cross-section view of an IMD 612 that includes pressure sensor assembly 536, the sensor axis 556 is substantially parallel to the longitudinal axis 610 of the IMD. All design considerations described herein regarding IMD 12 of FIGS. 1-3 apply equally to IMD 612 of FIG. 21 unless stated otherwise. In one or more embodiments, the sensor axis 556 is colinear with the longitudinal axis 610. In one or more embodiments, the sensor axis 556 is offset from the longitudinal axis 610 any suitable distance 611.

[0099] The diaphragm 558 extends through the cavity 554 and defines the measurement chamber 564 and the input chamber 566 of the cavity. At least a portion of the diaphragm 558 disposed in the cavity 554 defines the first electrode plate 568. As shown in FIG. 17, the first electrode plate 568 can be disposed on a pedestal 559 of the diaphragm 558 that extends from the first major surface 560 of the diaphragm. The pedestal 559 can be integral with the diaphragm 558. In one or more embodiments, the pedestal 559 can bemanufactured separately from the diaphragm 558 and disposed on the first major surface 560 of the diaphragm using any suitable technique. The first electrode plate 568 can be disposed on the pedestal 559 using any suitable technique.

[0100] The diaphragm 558 can be disposed in the sensor housing 546 such that at least a portion of the diaphragm is free to move in response to ambient pressure that is transferred to it by the passageway 572. In one or more embodiments, an edge 594 of the diaphragm 558 can be fixed or connected to at least one of the sensor substrate 578 or cover 580 using any suitable technique, e.g., welding, bonding, adhering, mechanically fastening, etc. In one or more embodiments, the edge 594 of the diaphragm 558 is fixed between the sensor substrate 578 and the cover 580 so that the portion of the diaphragm that defines the first electrode plate 568 can move in response to ambient pressure.

[0101] The pressure sensor assembly 536 can also include the second electrode plate 570 that is disposed on or at least partially within the region 585 of the sensor substrate 578 and along the sensor axis 556. The second electrode plate 570 is substantially parallel to the first electrode plate 568 and spaced apart from the first electrode plate any suitable distance. The first electrode plate 568 and the second electrode plate 570 form the variable capacitor 576 that is disposed along the sensor axis 556.

[0102] The second electrode plate 570 can be disposed on or at least partially within the region 585 of the sensor substrate 578 using any suitable technique. In one or more embodiments, the region 585 can include a nonconductive material such as sapphire. In one or more embodiments, an insulative layer 579 can be disposed in the region 585 between the sensor substrate 578 and the second electrode plate 570.

[0103] One or more vias 577 can be disposed through the sensor substrate 578 that electrically connect the second electrode plate 570 to one or more conductive pads 581 disposed on the outer surface 582 of the sensor substrate (FIG. 19). In one or more embodiments, an insulative layer 583 can be disposed between the one or more conductive pads 581 and the outer surface 582 of the sensor substrate 578. In one or more embodiments, the sensor substrate 578 can include an opening (e.g., opening 98 of sensor substrate 78 of FIG. 7) that can define the region 585 and that can be disposed through the first surface 548 of the sensor housing 546 to the cavity 554. The second electrode plate 570 can be disposed at least partially within the opening in the region 585 and electrically isolated from the sensor housing 546 by the insulative or dielectric material 579 (e.g.,dielectric material 71) disposed between the sensor housing and the second electrode plate. The second electrode plate 570 can be electrically connected to one or more electronic components disposed on or within the sensor housing 546 or disposed elsewhere on or within device housing 614 of the IMD 612 of FIG. 21 (e.g., one or more electronic components of electronic layers 40 of IMD 12) using any suitable technique.

[0104] The pressure sensor assembly 536 also includes one or more passageways 572 each extending between the inlet 574 disposed in the side surface 552 of the sensor housing 546 and the input chamber 566. At least one passageway 572 is configured to transfer ambient pressure to the diaphragm 558. The assembly 536 can include any suitable number of passageways 572. Further, each passageway 572 can take any suitable shape and have any suitable dimensions. The passageway 572 can be disposed in any suitable portion or portions of the assembly 536. In one or more embodiments, the passageway 572 can be disposed between the sensor substrate 578 and the cover 580. As shown in FIG. 15, the cover 580 is connected to the sensor substrate 578 by two or more standoffs or posts 502 that each extends between the inner surface 586 of the sensor substrate and the inner surface 588 of the cover. The assembly 536 can include any suitable number of standoffs 502 having any suitable dimensions. Further, each standoff 502 can take any suitable shape. The standoffs 502 can be disposed in any suitable location between the sensor substrate 578 and the cover 580. In essence, connection of the sensor substrate 578 and the cover 580 utilizing the standoffs 502 provides multiple passageways 572 from ambient atmosphere to the input chamber 566 disposed within the housing 546 of the assembly 536.

[0105] The pressure sensor assembly 536 includes a reference capacitor 596 that is disposed at least partially within the sensor housing 546. The reference capacitor 596 includes a first reference electrode 601 disposed on the first major surface 560 of the diaphragm 558 adjacent a periphery 561 (FIGS. 17-18) and a second reference electrode 603 disposed on an inner surface 586 of the sensor substrate 578 and aligned with the first reference electrode along the sensor axis 556. As shown in FIGS. 17-18, the first reference electrode 601 is disposed adjacent the periphery 561 of the diaphragm 558 on a portion of the diaphragm that remains fixed when a central portion of the diaphragm flexes in response to pressure waves that enter the assembly 536 from the ambient environment of the assembly. As a result, a distance between the first reference electrode 601 and thesecond reference electrode 603 remains fixed while a distance between the first electrode plate 568 and the second electrode plate 570 varies in response to flexing of the diaphragm 558 caused by changes in pressure in the input chamber 566.

[0106] The first reference electrode 601 can take any suitable shape and have any suitable dimensions. In the illustrated embodiment, the first reference electrode 601 can take a closed ring shape that circumscribes the first electrode plate 568 of the variable capacitor 576. In one or more embodiments, the first reference electrode 601 can be formed in two or more discrete segments adjacent the periphery 561 of the diaphragm. In one or more embodiments, the first reference electrode 601 can be defined by one or more portions of the diaphragm 558 when the diaphragm includes a conductive material. In one or more embodiments, the first reference electrode 601 can include one or more conductive layers disposed on the diaphragm or on a nonconductive layer disposed on the diaphragm.

[0107] The second reference electrode 603 can be disposed on any suitable portion or portions of the inner surface 586 of the sensor substrate 578. In one or more embodiments, the second reference electrode 603 can be disposed on or at least partially within the region 585 of the sensor substrate 578. The second reference electrode 603 can be aligned with the first reference electrode 601 along the sensor axis 556 as shown in FIG. 16. The second reference electrode 603 can take any suitable shape and have any suitable dimensions, e.g., the same shape and dimensions as the first reference electrode 601. In one or more embodiments, the first and second reference electrodes 601, 603 take the same shape and have the same dimensions. The second reference electrode 603 can include any suitable conductive material disposed on the inner surface 586 of the sensor substrate 578 (e.g., within the region 585) using any suitable technique. In one or more embodiments, the second reference electrode 603 can be defined by one or more portions of the sensor substrate 578 when the substrate includes a conductive material.

[0108] The reference capacitor 596 can be electrically connected to one or more electronic components of the electronic layers 40 or a controller (e.g., controller 97 of FIG. 4) using any suitable technique. Although depicted as including one reference capacitor 596, the assembly 536 can include any suitable number of reference capacitors.

[0109] As mentioned herein, the diaphragm 558 can be connected to the sensor substrate 578 using any suitable technique to form the measurement chamber 564. In one or more embodiments, the periphery 561 can be bonded to the sensor substrate 578, e.g., bywelding, laser welding, adhering, mechanically fastening, thermocompression bonding, etc. In one or more embodiments, at least one of the periphery 561 and the inner surface 586 of the sensor substrate 578 can be metallized using any suitable technique. The metallized portions of the diaphragm 558 and sensor substrate 578 can be bonded using any suitable technique. For example, as shown in FIG. 20, a patterned metal layer 587 can be disposed on the inner surface 586 of the sensor substrate 578 using any suitable technique. The metal layer 587 can take any suitable shape and have any suitable dimensions. As shown, the metal layer 587 is ring shaped and circumscribes the second reference electrode 603 and the second electrode plate 570. Similarly, a patterned metal layer 563 can be disposed on the first major surface 560 of the diaphragm 558 as shown in FIGS. 17-18 using any suitable technique. The metal layer 563 can take any suitable shape and have any suitable dimensions. As shown, the metal layer 563 is ring shaped and circumscribes the first reference electrode 601 and the first electrode plate 568. The metal layers 587 and 563 can be welded or bonded together using any suitable technique, e.g., welding, laser welding, adhering, mechanically fastening, thermocompression bonding, etc. In one or more embodiments, the bond between the metal layers 587 and 563 can hermetically seal the diaphragm 558 to the sensor substrate 578, thereby hermetically sealing the measurement chamber 564.

[0110] Any suitable technique can be utilized to form or manufacture the various embodiments of IMDs and pressure sensor assemblies described herein. For example, FIG. 14 is a flowchart of one method 400 that can be utilized to form IMD 12 of FIGS. 1- 10. Although described regarding IMD 12, the method 400 can be utilized to manufacture any suitable IMD that includes a pressure sensor assembly. At 402, the recess 90 of the pressure sensor assembly 36 can be disposed in the inner surface 86 of the sensor substrate 78 along the sensor axis 56 using any suitable technique, e.g., etching, ablation, laser ablation, etc. At 404, the second electrode plate 70 is disposed on or at least partially within the outer surface 82 of the sensor substrate 78 along the sensor axis 56 using any suitable technique. The diaphragm 58 can be disposed on or at least partially within the inner surface 86 of the sensor substrate 78 and over the recess 90 using any suitable technique to define the measurement chamber 64 between the diaphragm and the recess at 406. At least a portion of the diaphragm 58 disposed over the recess 90 defines the first electrode plate 68, and the first major surface 60 of the diaphragm is substantiallyorthogonal to the sensor axis 56. In one or more embodiments, the diaphragm 58 can be connected to the first electrode plate 68 using any suitable technique, e.g., welding, bonding, etc. The first electrode plate 68 and the second electrode plate 70 form the variable capacitor 76 along the sensor axis 56.[oni] At 408, the recess 92 is disposed in the inner surface 88 of the cover 80 using any suitable technique. The recess 92 of the cover 80 and the diaphragm 58 define the input chamber 66. The inner surface 88 of the cover 80 can be connected to the inner surface 86 of the sensor substrate 78 at 410 using any suitable technique such that the diaphragm 58 is disposed between the sensor substrate and the cover. In one or more embodiments, the cover 80 can be hermetically sealed to the sensor substrate 78 by, e.g., welding, bonding, diffusion bonding, etc. At 412, one or more passageways 72 can be disposed between the sensor substrate 78 and the cover 80 using any suitable technique such that each passageway extends between the inlet 74 disposed in the side surface 52 of the sensor housing 46 and the input chamber 66. For example, the passageway 72 can be disposed by connecting the sensor substrate 78 to the cover 80 utilizing at least two standoffs (e.g., standoff 302 of pressure sensor assembly 336 of FIG. 13) that extend between the inner surface 86 of the sensor substrate and the inner surface 88 of the cover.

[0112] At 414, the diaphragm 58 can optionally be electrically connected to the sensor housing 46 using any suitable technique. Further, the feedthrough 100 can optionally be disposed in the sensor housing 46 between the first surface 48 and the second surface 50 at 416 using any suitable technique. For example, the via 102 can be disposed through the sensor housing 46 between the first surface 48 and the second surface 50 of the sensor housing. The conductive material 104 (e.g., a feedthrough pin) can be disposed in the via 102 using any suitable technique. In one or more embodiments, dielectric material 106 can be disposed between the conductive material 104 and the via 102 to electrically isolate the conductive material from the sensor housing 46. In one or more embodiments, the feedthrough 100 can be disposed in the sensor housing 46 prior to connecting the inner surface 88 of the cover 80 to the inner surface 86 of the sensor substrate 78.

[0113] At 418, polymeric material can be disposed in one or more of the passageways 72 using any suitable technique. In one or more embodiments, an uncured or partially cured polymeric material can be disposed in one or more of the passageways 72, and the material can be completely cured using any suitable technique.

[0114] At 420 the electronics module 32 can optionally be electrically connected to the pressure sensor assembly 36 using any suitable technique. Further, the power source 30 can optionally be electrically connected to the pressure sensor assembly 36 and the electronics module 32 at 422. In one or more embodiments, the cover 80 can be connected to the power source 30 prior to connecting the cover to the sensor substrate 78. In such embodiments, the cover 80 can provide the header for the power source 30 such that the completed power source is then connected to the sensor substrate 78 to form the completed pressure sensor assembly 36. The electronics module 32, pressure sensor assembly 36, and power source 30 can optionally be disposed within the elongated housing 14 of the IMD 12 using any suitable technique at 424.

[0115] It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques). In addition, while certain aspects of this disclosure are described as being performed by a single module or unit for purposes of clarity, it should be understood that the techniques of this disclosure may be performed by a combination of units or modules associated with, for example, a medical device.

[0116] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media, which corresponds to a tangible medium such as data storage media (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer).

[0117] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor” as used hereinmay refer to any of the foregoing structure or any other physical structure suitable for implementation of the described techniques. Also, the techniques could be fully implemented in one or more circuits or logic elements.

[0118] This disclosure includes without limitation the following clauses:

[0119] Clause 1 : A pressure sensor assembly including a sensor housing having a first surface, a second surface substantially parallel to the first surface, and a side surface that extends between the first and second surfaces; a cavity disposed within the sensor housing along a sensor axis that is substantially orthogonal to the first surface; and a diaphragm disposed within the sensor housing along the sensor axis and including a first major surface and a second major surface. The first major surface is substantially orthogonal to the sensor axis. The diaphragm extends through the cavity and defines a measurement chamber and an input chamber of the cavity. Further, at least a portion of the diaphragm disposed in the cavity defines a first electrode plate. The assembly further includes a second electrode plate disposed on or at least partially within the first surface of the sensor housing along the sensor axis, where the second electrode plate is substantially parallel to the first electrode plate; and a passageway that extends between an inlet disposed in the side surface of the sensor housing and the input chamber and that is configured to transfer ambient pressure to the diaphragm. The first electrode plate and the second electrode plate form a variable capacitor disposed along the sensor axis.

[0120] Clause 2: The assembly of Clause 1, where the sensor housing further includes a sensor substrate and a cover connected to the sensor substrate, where an outer surface of the sensor substrate defines the first surface of the sensor housing and an outer surface of the cover defines the second surface of the sensor housing. Further, an inner surface of the sensor substrate faces an inner surface of the cover.

[0121] Clause 3: The assembly of Clause 2, where the passageway is disposed between the sensor substrate and the cover.

[0122] Clause 4: The assembly of any one of Clauses 2-3, where the sensor substrate is connected to the cover by two or more standoffs that extend between the inner surface of the sensor substrate and the inner surface of the cover.

[0123] Clause 5: The assembly of any one of Clauses 2-4, where the cavity is defined by a recess disposed in the inner surface of the sensor substrate and a recess disposed in the inner surface of the cover.

[0124] Clause 6: The assembly of any one of Clauses 2-5, where the diaphragm is disposed on or at least partially within the inner surface of the sensor substrate.

[0125] Clause 7: The assembly of any one of Clauses 1-6, where the sensor housing includes an elliptical shape in a plane orthogonal to the sensor axis.

[0126] Clause 8: The assembly of Clause 7, where the inlet of the passageway has an arc length of at least 0.01 radians and no greater than pi radians.

[0127] Clause 9: The assembly of any one of Clauses 1-8, where the diaphragm includes titanium.

[0128] Clause 10: The assembly of any one of Clauses 1-9, where the second electrode plate is formed in the device housing and extends between the first surface of the sensor housing and the cavity.

[0129] Clause 11 : The assembly of any one of Clauses 1-10, further including a feedthrough having a via that extends between the first surface and the second surface of the sensor housing and a conductive material disposed in the via.

[0130] Clause 12: The assembly of any one of Clauses 1-11, where the diaphragm is electrically connected to the sensor housing.

[0131] Clause 13: The assembly of any one of Clauses 1-12, further including a reference capacitor disposed on or at least partially within the sensor housing.

[0132] Clause 14: The assembly of any one of Clauses 1-13, further including a plurality of passageways each extending between an inlet disposed on the side surface of the sensor housing and the input chamber.

[0133] Clause 15: The assembly of any one of Clauses 1-14, further including a polymeric material disposed at least partially within the passageway.

[0134] Clause 16: The assembly of Clause 15, where the polymeric material includes a gel.

[0135] Clause 17: The assembly of any one of Clauses 15-16, where the polymeric material includes silicone.

[0136] Clause 18: An implantable medical device including a device housing and a pressure sensor assembly that forms a portion of the device housing. The pressure sensor assembly includes a sensor housing having a first surface, a second surface substantially parallel to the first surface, and a side surface that extends between the first and second surfaces; a cavity disposed within the sensor housing along a sensor axis that issubstantially orthogonal to the first surface; and a diaphragm disposed within the sensor housing along the sensor axis and including a first major surface and a second major surface. The first major surface is substantially orthogonal to the sensor axis. The diaphragm extends through the cavity and defines a measurement chamber and an input chamber of the cavity. Further, at least a portion of the diaphragm disposed in the cavity defines a first electrode plate. The assembly further includes a second electrode plate disposed on or at least partially within the first surface of the sensor housing along the sensor axis, where the second electrode plate is substantially parallel to the first electrode plate; and a passageway that extends between an inlet disposed in the side surface of the sensor housing and the input chamber and that is configured to transfer ambient pressure to the diaphragm. The first electrode plate and the second electrode plate form a variable capacitor disposed along the sensor axis.

[0137] Clause 19: The device of Clause 18, where the device housing extends along a longitudinal axis, and the sensor axis is substantially parallel to the longitudinal axis.

[0138] Clause 20: The device of any one of Clauses 18-19, further including an electronics module disposed within the device housing and electrically connected to the pressure sensor assembly.

[0139] Clause 21 : The device of Clause 20, further including a power source disposed within the device housing and electrically connected to the electronics module and the pressure sensor assembly.

[0140] Clause 22: The device of Clause 21, where the pressure sensor assembly is disposed between the electronics module and the power source.

[0141] Clause 23: The device of any one of Clauses 21-22, where the device housing and the pressure sensor assembly enclose the electronics module and the power source.

[0142] Clause 24: The device of any one of Clauses 21-23, where the pressure sensor assembly defines a header of the power source.

[0143] Clause 25: The device of any one of Clauses 18-24, further including a fixation element connected to the device housing.

[0144] Clause 26: The device of any one of Clauses 18-25, where the sensor housing further includes a sensor substrate and a cover connected to the sensor substrate, where an outer surface of the sensor substrate defines the first surface of the device housing and anouter surface of the cover defines the second surface of the sensor housing, and further where an inner surface of the sensor substrate faces an inner surface of the cover.

[0145] Clause 27: The device of Clause 26, where the passageway is disposed between the sensor substrate and the cover.

[0146] Clause 28: The device of any one of Clauses 26-27, where the sensor substrate is connected to the cover by two or more standoffs that extend between the inner surface of the sensor substrate and the inner surface of the cover.

[0147] Clause 29: The device of any one of Clauses 26-28, where the cavity is defined by a recess disposed in the inner surface of the sensor substrate and a recess disposed in the inner surface of the cover.

[0148] Clause 30: The device of any one of Clauses 26-29, where the diaphragm is disposed on or at least partially within the inner surface of the sensor substrate.

[0149] Clause 31 : The device of any one of Clauses 18-30, where the sensor housing includes an elliptical shape in a plane orthogonal to the sensor axis.

[0150] Clause 32: The device of Clause 31, where the inlet of the passageway has an arc length of at least 0.01 radians and no greater than pi radians.

[0151] Clause 33: The device of any one of Clauses 18-32, where the diaphragm includes titanium.

[0152] Clause 34: The device of any one of Clauses 18-33, where the second electrode plate is formed in the sensor housing and extends between the first surface of the sensor housing and the cavity.

[0153] Clause 35: The device of any one of Clauses 18-34, further including a feedthrough having a via that extends between the first surface and the second surface of the sensor housing and a conductive material disposed in the via.

[0154] Clause 36: The device of any one of Clauses 18-35, where the diaphragm is electrically connected to the sensor housing.

[0155] Clause 37: The device of any one of Clauses 18-36, further including a reference capacitor disposed on or at least partially within the sensor housing.

[0156] Clause 38: The device of any one of Clauses 18-37, further including a plurality of passageways each extending between an inlet disposed on the side surface of the sensor housing and the input chamber.

[0157] Clause 39: The device of any one of Clauses 18-38, further including a polymeric material disposed at least partially within the passageway.

[0158] Clause 40: The device of Clause 39, where the polymeric material includes a gel.

[0159] Clause 41 : The device of any one of Clauses 39-40, where the polymeric material comprises silicone.

[0160] Clause 42: A method including disposing a recess in an inner surface of a sensor substrate along a sensor axis that is substantially orthogonal to the inner surface of the sensor substrate; disposing a second electrode plate on or at least partially within an outer surface of the sensor substrate along the sensor axis; and disposing a diaphragm on or at least partially within the inner surface of the sensor substrate and over the recess to define a measurement chamber between the diaphragm and the recess. At least a portion of the diaphragm disposed over the recess defines a first electrode plate, a first major surface of the diaphragm is substantially orthogonal to the sensor axis, and the second electrode plate is substantially parallel to and spaced apart from the diaphragm. The method further includes disposing a recess in an inner surface of a cover; connecting the inner surface of the cover to the inner surface of the sensor substrate such that the diaphragm is disposed between the sensor substrate and the cover, where the sensor substrate and the cover provide a sensor housing, where the outer surface of the sensor substrate defines a first surface of the sensor housing and an outer surface of the cover defines a second surface of the sensor housing, and further where the recess of the cover and the diaphragm define an input chamber; and disposing a passageway between the sensor substrate and the cover. The passageway extends between an inlet disposed in a side surface of the sensor housing and the input chamber. The side surface extends between the first and second surfaces of the sensor housing. The first electrode plate and the second electrode plate form a variable capacitor disposed along the sensor axis. Further, the sensor substrate, cover, and variable capacitor form a pressure sensor assembly.

[0161] Clause 43 : The method of Clause 42, further including electrically connecting the diaphragm to the sensor housing.

[0162] Clause 44: The method of any one of Clauses 42 43, further including disposing a feedthrough in the sensor housing between the first surface and the second surface of the sensor housing.

[0163] Clause 45: The method of Clause 44, where disposing the feedthrough includes disposing a via through the sensor housing between the first surface and the second surface of the sensor housing.

[0164] Clause 46: The method of Clause 45, where disposing the feedthrough further includes disposing a conductive material in the via.

[0165] Clause 47: The method of any one of Clauses 42-46, where disposing the passageway includes connecting the sensor substrate to the cover utilizing at least two standoffs that extend between the inner surface of the sensor substrate and the inner surface of the cover.

[0166] Clause 48: The method of any one of Clauses 42-47, further including disposing a polymeric material in the passageway.

[0167] Clause 49: The method of Clause 48, further including curing the polymeric material.

[0168] Clause 50: The method of any one of Clauses 42-49, further including electrically connecting an electronics module to the pressure sensor assembly.

[0169] Clause 51 : The method of Clause 50, further including electrically connecting a power source to the pressure sensor assembly and the electronics module such that the assembly is disposed between the electronics module and the power source.

[0170] Clause 52: The method of Clause 51, further including disposing the electronics module, pressure sensor assembly, and power source within an elongated housing, where the sensor housing of the pressure sensor assembly forms a portion of the elongated housing.

[0171] Clause 53: A pressure sensor assembly extending along a sensor axis, the pressure sensor assembly including a sensor housing. The sensor housing includes a first surface substantially orthogonal to the sensor axis, a second surface substantially parallel to the first surface, and a side surface that extends between the first and second surfaces. The sensor housing further includes a sensor substrate, and a cover connected to the sensor substrate. An outer surface of the sensor substrate defines the first surface of the sensor housing and an outer surface of the cover defines the second surface of the sensor housing. Further, an inner surface of the sensor substrate faces an inner surface of the cover. The assembly further includes a cavity disposed within the sensor housing along the sensor axis; a diaphragm disposed within the sensor housing along the sensor axis and including afirst major surface and a second major surface, where the first major surface is substantially orthogonal to the sensor axis, where the diaphragm extends through the cavity and defines a measurement chamber and an input chamber of the cavity, and where at least a portion of the diaphragm disposed in the cavity defines a first electrode plate; and a second electrode plate disposed on or at least partially within a region of the sensor substrate of the sensor housing along the sensor axis, where the second electrode plate is substantially parallel to the first electrode plate. The assembly further includes a passageway that extends between an inlet disposed in the side surface of the sensor housing and the input chamber and is configured to transfer ambient pressure to the diaphragm. The first electrode plate and the second electrode plate form a variable capacitor disposed along the sensor axis.

[0172] Clause 54: The assembly of Clause 53, where the region of the sensor substrate includes a nonconductive material.

[0173] Clause 55: The assembly of Clause 54, where the nonconductive material of the region of the sensor substrate includes sapphire.

[0174] Clause 56: The assembly of any one of Clauses 53-55, where the first electrode plate is disposed on a pedestal that extends from the first major surface of the diaphragm along the sensor axis.

[0175] Clause 57: The assembly of any one of Clauses 53-56, further including a reference capacitor disposed at least partially within the sensor housing.

[0176] Clause 58: The assembly of Clause 57, where the reference capacitor includes a first reference electrode disposed on the first major surface of the diaphragm adjacent a periphery of the first major surface of the diaphragm and a second reference electrode disposed on the inner surface of the sensor substrate and aligned with the first reference electrode along the sensor axis.

[0177] Clause 59: The assembly of any one of Clauses 53-58, where the passageway is disposed between the sensor substrate and the cover.

[0178] Clause 60: The assembly of any one of Clauses 53-59, where the sensor substrate is connected to the cover by two or more standoffs that extend between the inner surface of the sensor substrate and the inner surface of the cover.

[0179] Clause 61 : The assembly of any one of Clauses 53-60, where the cavity is defined by a recess disposed in the inner surface of the sensor substrate and a recess disposed in the inner surface of the cover.

[0180] Clause 62: The assembly of any one of Clauses 53-61, where the diaphragm is disposed on or at least partially within the inner surface of the sensor substrate.

[0181] Clause 63: The assembly of any one of Clauses 53-61, further including a polymeric material disposed at least partially within the passageway.

[0182] Clause 64: The assembly of Clause 63, where the polymeric material includes a gel.

[0183] Clause 65: The assembly of any one of Clauses 63-64, where the polymeric material includes silicone.

[0184] Clause 66: An implantable medical device including a device housing and the pressure sensor assembly of any one of Clauses 53-65, where the pressure sensor assembly forms a portion of the device housing.

[0185] Clause 67: The device of Clause 66, where the device housing extends along a longitudinal axis, and where the sensor axis is substantially parallel to the longitudinal axis.

[0186] Clause 68: The device of any one of Clauses 66-67, further including an electronics module disposed within the device housing and electrically connected to the pressure sensor assembly.

[0187] Clause 69: The device of Clause 68, further including a power source disposed within the device housing and electrically connected to the electronics module and the pressure sensor assembly.

[0188] Clause 70: The device of Clause 69, where the pressure sensor assembly is disposed between the electronics module and the power source.

[0189] Clause 71 : The device of any one of Clauses 69-70, where the device housing and the pressure sensor assembly enclose the electronics module and the power source.

[0190] Clause 72: The device of any one of Clauses 69-71, where the pressure sensor assembly defines a header of the power source.

[0191] Clause 73 : The device of any one of Clauses 66-72, further including a fixation element connected to the device housing.

[0192] All references and publications cited herein are expressly incorporated herein by reference in their entirety into this disclosure, except to the extent they may directly contradict this disclosure. Illustrative embodiments of this disclosure are discussed and reference has been made to possible variations within the scope of this disclosure. These and other variations and modifications in the disclosure will be apparent to those skilled in the art without departing from the scope of the disclosure, and it should be understood that this disclosure is not limited to the illustrative embodiments set forth herein. Accordingly, the disclosure is to be limited only by the claims provided below.

Claims

WHAT IS CLAIMED IS:

1. A pressure sensor assembly comprising: a sensor housing comprising a first surface, a second surface substantially parallel to the first surface, and a side surface that extends between the first and second surfaces; a cavity disposed within the sensor housing along a sensor axis that is substantially orthogonal to the first surface; a diaphragm disposed within the sensor housing along the sensor axis and comprising a first major surface and a second major surface, wherein the first major surface is substantially orthogonal to the sensor axis, wherein the diaphragm extends through the cavity and defines a measurement chamber and an input chamber of the cavity, wherein at least a portion of the diaphragm disposed in the cavity defines a first electrode plate; a second electrode plate disposed on or at least partially within the first surface of the sensor housing along the sensor axis, wherein the second electrode plate is substantially parallel to the first electrode plate; and a passageway that extends between an inlet disposed in the side surface of the sensor housing and the input chamber and is configured to transfer ambient pressure to the diaphragm; wherein the first electrode plate and the second electrode plate form a variable capacitor disposed along the sensor axis.

2. The assembly of claim 1, wherein the sensor housing further comprises a sensor substrate and a cover connected to the sensor substrate, wherein an outer surface of the sensor substrate defines the first surface of the sensor housing and an outer surface of the cover defines the second surface of the sensor housing, and further wherein an inner surface of the sensor substrate faces an inner surface of the cover.

3. The assembly of claim 2, wherein the sensor substrate is connected to the cover by two or more standoffs that extend between the inner surface of the sensor substrate and the inner surface of the cover.

4. The assembly of any one of claims 1-3, wherein the second electrode plate is formed in the sensor housing and extends between the first surface of the sensor housing and the cavity.

5. The assembly of any one of claims 1-4, further comprising a reference capacitor disposed on or at least partially within the sensor housing.

6. The assembly of any one of claims 1-5, further comprising a plurality of passageways each extending between an inlet disposed on the side surface of the sensor housing and the input chamber.

7. An implantable medical device comprising a device housing and the pressure sensor assembly of any one of claims 1-6.

8. The device of claim 7, wherein the device housing extends along a longitudinal axis, wherein the sensor axis is substantially parallel to the longitudinal axis.

9. The device of any one of claims 7-8, further comprising: an electronics module disposed within the device housing and electrically connected to the pressure sensor assembly; and a power source disposed within the device housing and electrically connected to the electronics module and the pressure sensor assembly.

10. The device of claim 9, wherein the pressure sensor assembly defines a header of the power source.

11. A method comprising: disposing a recess in an inner surface of a sensor substrate along a sensor axis that is substantially orthogonal to the inner surface of the sensor substrate; disposing a second electrode plate on or at least partially within an outer surface of the sensor substrate along the sensor axis;disposing a diaphragm on or at least partially within the inner surface of the sensor substrate and over the recess to define a measurement chamber between the diaphragm and the recess, wherein at least a portion of the diaphragm disposed over the recess defines a first electrode plate, wherein a first major surface of the diaphragm is substantially orthogonal to the sensor axis, and wherein the second electrode plate is substantially parallel to and spaced apart from the diaphragm; disposing a recess in an inner surface of a cover; connecting the inner surface of the cover to the inner surface of the sensor substrate such that the diaphragm is disposed between the sensor substrate and the cover, wherein the sensor substrate and the cover provide a sensor housing, wherein the outer surface of the sensor substrate defines a first surface of the sensor housing and an outer surface of the cover defines a second surface of the sensor housing, and further wherein the recess of the cover and the diaphragm define an input chamber; and disposing a passageway between the sensor substrate and the cover, wherein the passageway extends between an inlet disposed in a side surface of the sensor housing and the input chamber, wherein the side surface extends between the first and second surfaces of the sensor housing; wherein the first electrode plate and the second electrode plate form a variable capacitor disposed along the sensor axis, and further wherein the sensor substrate, cover, and variable capacitor form a pressure sensor assembly.

12. A pressure sensor assembly extending along a sensor axis, the pressure sensor assembly comprising: a sensor housing comprising: a first surface substantially orthogonal to the sensor axis; a second surface substantially parallel to the first surface; a side surface that extends between the first and second surfaces; a sensor substrate; and a cover connected to the sensor substrate, wherein an outer surface of the sensor substrate defines the first surface of the sensor housing and an outer surface of the cover defines the second surface of the sensor housing, and further wherein an inner surface of the sensor substrate faces an inner surface of the cover;a cavity disposed within the sensor housing along the sensor axis; a diaphragm disposed within the sensor housing along the sensor axis and comprising a first major surface and a second major surface, wherein the first major surface is substantially orthogonal to the sensor axis, wherein the diaphragm extends through the cavity and defines a measurement chamber and an input chamber of the cavity, wherein at least a portion of the diaphragm disposed in the cavity defines a first electrode plate; a second electrode plate disposed on or at least partially within a region of the sensor substrate of the sensor housing along the sensor axis, wherein the second electrode plate is substantially parallel to the first electrode plate; and a passageway that extends between an inlet disposed in the side surface of the sensor housing and the input chamber and is configured to transfer ambient pressure to the diaphragm; wherein the first electrode plate and the second electrode plate form a variable capacitor disposed along the sensor axis.

13. The assembly of claim 12, wherein the first electrode plate is disposed on a pedestal that extends from the first major surface of the diaphragm along the sensor axis.

14. The assembly of any one of claims 12-13, further comprising a reference capacitor disposed at least partially within the sensor housing, wherein the reference capacitor comprises a first reference electrode disposed on the first major surface of the diaphragm adjacent a periphery of the first major surface of the diaphragm and a second reference electrode disposed on the inner surface of the sensor substrate and aligned with the first reference electrode along the sensor axis.

15. An implantable medical device comprising a device housing and the pressure sensor assembly of any one of claims 12-14, wherein the pressure sensor assembly forms a portion of the device housing, and further wherein the device housing extends along a longitudinal axis, wherein the sensor axis is substantially parallel to the longitudinal axis.

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