Implantable molded interconnect device assembly frame for optical emitter

Abstract

An example implantable medical device assembly includes a frame configured to house an optical emitter for generating light. The frame includes an upper surface, a lower surface, and at least one electrically-conductive path between a first pad on the lower surface and a second pad within the frame. The second pad is configured for connection to an electrical terminal of the optical emitter, and the first pad is configured for soldering to a partially-metallized substrate with a transparent portion, the transparent portion configured to pass at least a portion of the light generated by the optical emitter.

Description

IMPLANTABLE MOLDED INTERCONNECT DEVICE ASSEMBLY FRAME FOR OPTICAL EMITTER

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 580,141, filed September 1, 2023, the entire content of which is incorporated herein by reference.TECHNICAL FIELD

[0002] This disclosure relates generally to implantable medical devices and, more particularly, to an implantable device assembly frame for an optical emitter.BACKGROUND

[0003] Implantable medical devices (IMDs) for monitoring a physiological parameter or delivering a therapy may include an optical emitter and an optical sensor. The optical emitter applies light energy to living tissue. The optical sensor detects changes in light modulation as the light energy from the optical emitter travels through, and is scattered or absorbed by, the tissue. These changes in light modulation can be used to determine a physiological parameter from which a patient state or a need or desire for therapy can be assessed. Examples of such IMDs include heart monitors, blood pressure monitors, pacemakers, implantable cardiovascular defibrillators, myostimulators, neurological stimulators, drug delivery devices, insulin pumps, glucose monitors, tissue perfusion monitors, blood oxygen saturation (SpCh) monitors, tissue (skeletal muscle) oxygen saturation (StCL) monitors, and the like. Monitoring such physiological parameters provides useful measures which can be utilized to manage therapies for treating a medical condition. For example, a decrease in blood oxygen saturation or in tissue perfusion may be associated with inadequate cardiac output or respiratory function. Thus, monitoring allows an implantable medical device to respond to a decrease in oxygen saturation or tissue perfusion, for example, by delivering electrical stimulation therapy to the heart to restore a normal hemodynamic function.SUMMARY

[0004] For many IMD applications, the physical volume available to accommodate optical components is limited. Commercially-available, off-the-shelf components may be too large and bulky for use in a practical IMD, and expensive customized approaches maybe required. Moreover, many IMDs that use optical emitters require a so-called “deadbug” (reverse-mount) configuration where a light emission of the optical emitter and a set of solder leads for the optical emitter are both provided on a lower surface of the IMD. Commercially-available dead-bug component frames can be much too large to integrate into a practical IMD. In addition, commercially-available component frames may provide a large light emission angle, with some light exiting from the side of the frame. This sideexiting light comes from the optical emitter when the emitter is operating. The sideexiting light can reach an optical sensor of the IMD, causing a sensor output signal to exhibit a DC offset, and potentially swamping out or otherwise obscuring any useful signal that the sensor may be sensing.

[0005] The present disclosure describes devices and techniques for creating a molded interconnect device assembly frame for accommodating an optical emitter such as a lensed light-emitting diode (LED). In some examples described herein, the frame provides a dead-bug mounting arrangement for the optical emitter, configured to provide a light emission of the optical emitter, as well as a set of solder leads for the optical emitter, on a lower surface of the assembly. In some examples, the frame provides a reverse-lead configuration for the optical emitter. A frame formed according to the techniques of this disclosure may advantageously accommodate a commercial off-the-shelf (COTS) optical emitter while reducing or eliminating any light exiting the side of the frame, and providing a form factor suitable for use in an IMD.

[0006] In some examples described herein, an implantable medical device assembly comprises a frame configured to house an optical emitter for generating light, the frame comprising an upper surface, a lower surface, and at least one electrically-conductive path between a first pad on the lower surface and a second pad within the frame, wherein the second pad is configured for connection to an electrical terminal of the optical emitter, wherein the first pad is configured for soldering to a partially-metallized substrate with a transparent portion, to form an electrical connection between the lower surface and the substrate, and wherein the transparent portion is configured to pass at least a portion of the light generated by the optical emitter.

[0007] In some examples described herein, a method for manufacturing an implantable medical device assembly comprises molding a frame configured to house an optical emitter for generating light, the frame comprising an upper surface, a lower surface, and at least one electrically-conductive path between a first pad on the lower surface and asecond pad within the frame, wherein the second pad is configured for connection to an electrical terminal of the optical emitter, wherein the first pad is configured for soldering to a partially-metallized substrate with a transparent portion, to form an electrical connection between the lower surface and the substrate, and wherein the transparent portion is configured to pass at least a portion of the light generated by the optical emitter.

[0008] The details of one or more examples of the techniques of this disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a block diagram of an illustrative implantable medical device (IMD) in accordance with one or more aspects of this disclosure.

[0010] FIG. 2 is a top view of an illustrative device assembly frame in accordance with one or more aspects of this disclosure.

[0011] FIG. 3 is a side sectional view of an illustrative device assembly frame along axis A-A of FIG. 2 in accordance with one or more aspects of this disclosure.

[0012] FIG. 4 is a side sectional view of an illustrative device assembly frame along axis B-B of FIG. 2 in accordance with one or more aspects of this disclosure.

[0013] FIG. 5 is a diagrammatic representation of an illustrative frame incorporating an optical emitter, and configured to perform one or more tissue measurements in accordance with one or more aspects of this disclosure.

[0014] FIG. 6 is a flowchart illustrating an example technique for forming a device assembly frame in accordance with one or more aspects of this disclosure.

[0015] FIG. 7 is a perspective drawing illustrating an example configuration for the IMD of FIG. 1.

[0016] FIG. 8 is a perspective drawing illustrating another example configuration for the IMD of FIG. 1.DETAILED DESCRIPTION

[0017] The present disclosure describes devices and techniques for creating a molded interconnect device assembly frame for accommodating an optical emitter, such as alensed light-emitting diode (LED). The frame provides a dead-bug mounting arrangement for the optical emitter, configured to support a light emission of the optical emitter, as well as provide a set of solder leads for the optical emitter, on a lower surface of the frame. A frame formed according to the techniques of this disclosure may advantageously accommodate a commercial off-the-shelf (COTS) optical emitter while reducing or eliminating any light exiting the side of the frame, and providing a form factor suitable for use in an IMD.

[0018] FIG. 1 is a block diagram of an illustrative implantable medical device (IMD) 100 in accordance with one or more aspects of this disclosure. The IMD 100 includes a source 101 of light, such as an LED or a laser. The source 101 may apply the light to a living tissue 105. As the light travels through the tissue 105, scattered light 109 can be produced. The scattered light 109 may have a mean path 107, determined as an average of a plurality of scattered light paths of the scattered light 109. At least a portion of the scattered light 109 may be incident upon an optical detector 103, such as a photocell. The optical detector 103 can convert the incident light into a modulated electrical signal that can be used to determine one or more characteristics of the tissue 105. For example, these one or more characteristics may include a systolic blood pressure, a diastolic blood pressure, a glucose level, a blood oxygen saturation (SpCh) level, a tissue (skeletal muscle) oxygen saturation (StCL) level, a tissue impedance, and / or the like.

[0019] According to various embodiments, the distance between the source 101 and the detector 103 may be selected based on various consideration. For example, the form factor of the device 100 may impose certain extremes on this placement, e.g., between 0mm (immediately adjacent) and 10mm distance between the source 101 and the detector 103 (where the maximum length of the device 100 is 10mm). In some embodiments, the distance may be determined by the wavelengths used in the application. For example, an application using visible or infrared light might place the source 101 and the detector 103 between 3 -7mm apart. More specific wavelength ranges may correlate to different distances- e.g., for green light, 0-3 mm may be used; for amber light, 3-4 mm may be used; and for infrared, 4-7mm may be used. As another consideration, the desired depth of penetration of the mean path 107 may be considered in choosing the distance between the source 101 and the detector 103; for example, a distance of 6mm for certain wavelengths may yield a tissue depth of 3mm for the mean path 107. Various other arrangements anddistances the source 101 and the detector 103 will be apparent based on the particular application being implemented by the device 100.

[0020] FIG. 2 is a top view of an illustrative device assembly frame 104 for the light source 101 in accordance with one or more aspects of this disclosure. In some examples, a width of the frame 104 along axis A-A is in a range of about 1.5 to 3.0 millimeters, and a length of the frame 104 along axis B-B is in a range of about 1.0 to 2.0 millimeters. In a further example, the width of the frame 104 along axis A-A is about 2.3 millimeters, and the length of the frame 104 along axis B-B is about 1.5 millimeters. In a further example, a depth of the frame 104 is in a range of about 0.5 millimeters to 1.0 millimeters. In another further example, a depth of the frame 104 is about 0.7 millimeters. In some examples, the frame 104 is molded using plastic and / or epoxy, and one or more conductive paths are fabricated on the frame 104 using metallization. In an alternate example, the assembly frame 104 is configured to accommodate a light sensor.

[0021] FIG. 3 is a side sectional view of an illustrative device assembly frame 104 along axis A-A of FIG. 2 in accordance with one or more aspects of this disclosure. In some examples described herein, the frame 104 is configured to house an optical emitter, such as a lensed LED 108, for generating light. The frame 104 may include an upper surface 123, a lower surface 125, and at least one electrically-conductive path between the lower surface 125 and a surface within the frame 104. In one example, a first electrically- conductive path 106 is provided between a first pad 131 on the lower surface 125 and a second pad 127 within the frame 104, and a second electrically-conductive path 116 is provided between a third pad 133 on the lower surface 125 and a fourth pad 129 within the frame 104. The second pad 127 can be configured for connection to a first electrical terminal 112 of the LED 108, and the fourth pad 129 can be configured for connection to a second electrical terminal 113 of the LED 108.

[0022] Below the lower surface 125, a transparent, partially metallized substrate 110 can be configured to pass at least a portion of the light generated by the optical emitter. In some examples, the substrate 110 comprises a sapphire window. In other examples, the substrate 110 comprises a transparent material that can be metallized, such as glass, quartz, and / or a high-temperature plastic. In some examples, metallization may comprise thin film metal sputtering or plating. For example, the metallization can be applied to the substrate 110 by sputtering in a vacuum chamber to form a blanket metal layer. Then the blanket metal layer can be etched into a pattern to form an electrical interconnect similarto a printed wiring board, or an interconnect on an integrated circuit. In some examples, a metal can be plated over these conductor patterns to create very thick conductors for high- current applications.

[0023] In some examples described herein, the frame 104 includes at least one opaque surface configured for reducing or eliminating any light exiting from at least one side of the frame 104. For example, the at least one opaque surface may include the first and second electrically-conductive paths 106, 116. Additionally or alternatively, the at least one opaque surface may include one or more non-conductive surfaces of the frame 104 which can be fabricated, for example, of plastic and / or epoxy.

[0024] In some examples described herein, the frame 104 is arranged for accommodating a commercial, off-the-shelf (COTS) LED 108 having an integrated lens. In one illustrative example, the LED 108 can be a commercially-packaged LED having a package size of, for example, 1.6 millimeters by 0.8 millimeters. In a further example, the COTS LED 108 is not designed by its manufacturer for a dead -bug mounting configuration. In another further example, the COTS LED 108 is no larger than about 1.6 millimeters in width by 0.8 millimeters in length.

[0025] In a further example described herein, the first pad 131 and the third pad 133 are optimized for best metal to mold adhesion and / or minimum solder joint thickness, wherein the frame 104 is fabricated using a molding process. For example, a maximum part thickness for the frame 104 and LED 108 mounted therein can be less than about 1.2 millimeters. In some examples, the frame 104 is fabricated of plastic and / or epoxy.

[0026] FIG. 4 is a side sectional view of an illustrative device assembly frame 104 along axis B-B of FIG. 2 in accordance with one or more aspects of this disclosure. When an injection molding process is used to fabricate the frame 104, a cavity in a mold for the frame 104 may contain a small opening comprising the one or more tab gates 119, which allow hot plastic to enter the cavity before passing through and around the internal features of the mold until the mold is filled. In some examples, the frame 104 may include one or more tab gates 119 along one or more sides of the frame 104. In a further example, the one or more tab gates 119 each comprise a trapezoidal block milled into a parting line on an exterior surface of the frame 104. In one example, the tab gates 119 can be placed in a thicker wall section of the frame 104, than at least one other wall section of the frame 104.

[0027] FIG. 5 is a diagrammatic representation of an illustrative optical emitter 101 incorporating the frame 104 shown in FIGs. 3-4, and configured to perform one or more tissue measurements in accordance with one or more aspects of this disclosure. The LED 108 generates light which travels through the transparent portion 110 and is incident upon a layer of living tissue 105 (FIG. 1). As the light travels through the tissue 105, scattered light may be produced. At least a portion of the scattered light 109 may be incident upon optical detector 103 (FIG. 1), such as a photocell. The optical detector can convert the incident light into a modulated electrical signal that can be used to determine one or more characteristics of the tissue 105. For example, these one or more characteristics may include a systolic blood pressure, a diastolic blood pressure, a glucose level, a blood oxygen saturation (SpO2) level, a tissue (skeletal muscle) oxygen saturation (StO2) level, a tissue impedance, and / or the like.

[0028] FIG. 6 is a flowchart illustrating an example technique for forming a device assembly frame in accordance with one or more aspects of this disclosure. At block 701, a device assembly frame 104 (FIGs. 2-5) is molded, for example, using plastic and / or epoxy. The frame 104 is configured to house the optical emitter 101. The optical emitter 101, such as the LED 108, is configured for generating light. The frame 104 includes the upper surface 123 (FIG. 3), the lower surface 125, the first electrically-conductive path 106 between the first pad 131 and the second pad 127, and the second electrically-conductive path 116 between the third pad 133 and the fourth pad 129. The second pad 127 is configured for connection to the first electrical terminal 112 of the LED 108, and the fourth pad 129 is configured for connection to the second electrical terminal 113 of the LED 108. The lower surface 125 includes the transparent portion 110 configured to pass at least a portion of the light generated by the optical emitter 101.

[0029] At block 702 (FIG. 6), the LED 108 (FIG. 3) is placed into the frame 104 such that a lens portion of the LED 108 faces in a downward direction towards the lower surface 125. The first electrical terminal 112 contacts the second pad 127, and the second electrical terminal 113 contacts the fourth pad 129. At block 703 (FIG. 6), the first electrical terminal 112 is soldered to the second pad 127, and the second electrical terminal 113 is soldered to the fourth pad 129.

[0030] FIG. 7 is a perspective drawing illustrating an IMD 10A, which may be an example configuration of IMD 100 of FIG. 1. In the example shown in FIG. 7, IMD 10A may be embodied as a monitoring device having housing 612, proximal electrode 616Aand distal electrode 616B. Housing 612 may further comprise first major surface 614, second major surface 618, proximal end 620, and distal end 622. Housing 612 encloses electronic circuitry located inside the IMD 10A and protects the circuitry contained therein from body fluids. Housing 612 may be hermetically sealed and configured for subcutaneous implantation. Electrical feedthroughs provide electrical connection of electrodes 616A and 616B.

[0031] In the example shown in FIG. 7, IMD 10A is defined by a length L, a width W and thickness or depth D and is in the form of an elongated rectangular prism wherein the length L is much larger than the width W, which in turn is larger than the depth D. In one example, the geometry of the IMD 10A - in particular a width W greater than the depth D - is selected to allow IMD 10A to be inserted under the skin of the patient using a minimally invasive procedure and to remain in the desired orientation during insertion. For example, the device shown in FIG. 8 includes radial asymmetries (notably, the rectangular shape) along the longitudinal axis that maintains the device in the proper orientation following insertion. For example, the spacing between proximal electrode 616A and distal electrode 616B may range from 5 millimeters (mm) to 55 mm, 30 mm to 55 mm, 35 mm to 55 mm, and from 40 mm to 55 mm and may be any range or individual spacing from 5 mm to 60 mm. In addition, IMD 10A may have a length E that ranges from 30 mm to about 70 mm. In other examples, the length L may range from 5 mm to 60 mm, 40 mm to 60 mm, 45 mm to 60 mm and may be any length or range of lengths between about 30 mm and about 70 mm. In addition, the width W of major surface 614 may range from 3 mm to 15, mm, from 3 mm to 10 mm, or from 5 mm to 15 mm, and may be any single or range of widths between 3 mm and 15 mm. The thickness of depth D of IMD 10A may range from 2 mm to 15 mm, from 2 mm to 9 mm, from 2 mm to 5 mm, from 5 mm to 15 mm, and may be any single or range of depths between 2 mm and 15 mm. In addition, IMD 10A according to an example of the present disclosure is has a geometry and size designed for ease of implant and patient comfort. Examples of IMD 10A described in this disclosure may have a volume of three cubic centimeters (cm) or less, 1.5 cubic cm or less or any volume between three and 1.5 cubic centimeters.

[0032] In the example shown in FIG. 7, once inserted within the patient, the first major surface 614 faces outward, toward the skin of the patient while the second major surface 618 is located opposite the first major surface 614. In addition, in the example shown in FIG. 8, proximal end 620 and distal end 622 are rounded to reduce discomfort andirritation to surrounding tissue once inserted under the skin of the patient. IMD 10A, including instrument and method for inserting IMD 10 is described, for example, in U.S. Patent Publication No. 2014 / 0276928, incorporated herein by reference in its entirety.

[0033] Proximal electrode 616A is at or proximate to proximal end 620, and distal electrode 616B is at or proximate to distal end 622. Proximal electrode 616A and distal electrode 616B are used to sense cardiac EGM signals, e.g., ECG signals, thoracically outside the ribcage, which may be sub-muscularly or subcutaneously. Cardiac signals may be stored in a memory of IMD 10A, and data may be transmitted via integrated antenna 630A to another device, which may be another implantable device or an external device, such as external device 612. In some example, electrodes 616A and 616B may additionally or alternatively be used for sensing any bio-potential signal of interest, which may be, for example, an EGM, EEG, EMG, or a nerve signal, or for measuring impedance, from any implanted location.

[0034] In the example shown in FIG. 7, proximal electrode 616A is at or in close proximity to the proximal end 620 and distal electrode 616B is at or in close proximity to distal end 622. In this example, distal electrode 616B is not limited to a flattened, outward facing surface, but may extend from first major surface 614 around rounded edges 624 and / or end surface 626 and onto the second major surface 618 so that the electrode 616B has a three-dimensional curved configuration. In some examples, electrode 616B is an uninsulated portion of a metallic, e.g., titanium, part of housing 612.

[0035] In the example shown in FIG. 7, proximal electrode 616A is located on first major surface 614 and is substantially flat, and outward facing. However, in other examples proximal electrode 616A may utilize the three dimensional curved configuration of distal electrode 616B, providing a three dimensional proximal electrode (not shown in this example). Similarly, in other examples distal electrode 616B may utilize a substantially flat, outward facing electrode located on first major surface 614 similar to that shown with respect to proximal electrode 616A.

[0036] The various electrode configurations allow for configurations in which proximal electrode 616A and distal electrode 616B are located on both first major surface 614 and second major surface 618. In other configurations, such as that shown in FIG. 7, only one of proximal electrode 616A and distal electrode 616B is located on both major surfaces 614 and 618, and in still other configurations both proximal electrode 616A and distal electrode 616B are located on one of the first major surface 614 or the second majorsurface 618 (e.g., proximal electrode 616A located on first major surface 614 while distal electrode 616B is located on second major surface 618). In another example, IMD 10A may include electrodes on both major surface 614 and 618 at or near the proximal and distal ends of the device, such that a total of four electrodes are included on IMD 10A. Electrodes 616A and 616B may be formed of a plurality of different types of biocompatible conductive material, e.g. stainless steel, titanium, platinum, iridium, or alloys thereof, and may utilize one or more coatings such as titanium nitride or fractal titanium nitride.

[0037] In the example shown in FIG. 7, proximal end 620 includes a header assembly 628 that includes one or more of proximal electrode 616A, integrated antenna 630A, antimigration projections 632, and / or suture hole 634. Integrated antenna 630A is located on the same major surface (i.e., first major surface 614) as proximal electrode 616A and is also included as part of header assembly 628. Integrated antenna 630A allows IMD 10A to transmit and / or receive data. In other examples, integrated antenna 630A may be formed on the opposite major surface as proximal electrode 616A, or may be incorporated within the housing 612 of IMD 10A. In the example shown in FIG. 7, anti-migration projections 632 are located adjacent to integrated antenna 630A and protrude away from first major surface 614 to prevent longitudinal movement of the device. In the example shown in FIG. 7, anti-migration projections 632 include a plurality (e.g., nine) small bumps or protrusions extending away from first major surface 614. As discussed above, in other examples anti-migration projections 632 may be located on the opposite major surface as proximal electrode 616A and / or integrated antenna 630A. In addition, in the example shown in FIG. 7, header assembly 628 includes suture hole 634, which provides another means of securing IMD 10A to the patient to prevent movement following insertion. In the example shown, suture hole 634 is located adjacent to proximal electrode 616A. In one example, header assembly 628 is a molded header assembly made from a polymeric or plastic material, which may be integrated or separable from the main portion of IMD 10A.

[0038] FIG. 8 is a perspective drawing illustrating another IMD 10B, which may be another example configuration of IMD 100 from FIG. 1. IMD 10B of FIG. 8 may be configured substantially similarly to IMD 10A of FIG. 7, with differences between them discussed herein.

[0039] IMD 10B may include a leadless, subcutaneously-implantable monitoring device, e.g. an ICM. IMD 10B includes housing having a base 640 and an insulative cover 642. Proximal electrode 616C and distal electrode 616D may be formed or placed on an outer surface of cover 642. Various circuitries and components of IMD 10B, e.g., described above with respect to FIG. 1, may be formed or placed on an inner surface of cover 642, or within base 640. In some examples, a battery or other power source of IMD 10B may be included within base 640. In the illustrated example, antenna 630B is formed or placed on the outer surface of cover 642, but may be formed or placed on the inner surface in some examples. In some examples, insulative cover 642 may be positioned over an open base 640 such that base 640 and cover 642 enclose the circuitries and other components and protect them from fluids such as body fluids. The housing including base 640 and insulative cover 642 may be hermetically sealed and configured for subcutaneous implantation.

[0040] Circuitries and components may be formed on the inner side of insulative cover 642, such as by using flip-chip technology. Insulative cover 642 may be flipped onto a base 640. When flipped and placed onto base 640, the components of IMD 10B formed on the inner side of insulative cover 642 may be positioned in a gap 644 defined by base 640. Electrodes 616C and 616D and antenna 630B may be electrically connected to circuitry formed on the inner side of insulative cover 642 through one or more vias (not shown) formed through insulative cover 642. Insulative cover 642 may be formed of sapphire (i.e., corundum), glass, parylene, and / or any other suitable insulating material. Base 640 may be formed from titanium or any other suitable material (e.g., a biocompatible material). Electrodes 616C and 616D may be formed from any of stainless steel, titanium, platinum, iridium, or alloys thereof. In addition, electrodes 616C and 616D may be coated with a material such as titanium nitride or fractal titanium nitride, although other suitable materials and coatings for such electrodes may be used.

[0041] In the example shown in FIG. 8, the housing of IMD 10B defines a length L, a width W and thickness or depth D and is in the form of an elongated rectangular prism wherein the length L is much larger than the width W, which in turn is larger than the depth D, similar to IMD 10A of FIG. 7. For example, the spacing between proximal electrode 616C and distal electrode 616D may range from 5 mm to 50 mm, from 30 mm to 50 mm, from 35 mm to 45 mm, and may be any single spacing or range of spacings from 5 mm to 50 mm, such as approximately 40 mm. In addition, IMD 10B may have a length Lthat ranges from 5 mm to about 70 mm. In other examples, the length L may range from 30 mm to 70 mm, 40 mm to 60 mm, 45 mm to 55 mm, and may be any single length or range of lengths from 5 mm to 50 mm, such as approximately 45 mm. In addition, the width W may range from 3 mm to 15 mm, 5 mm to 15 mm, 5 mm to 10 mm, and may be any single width or range of widths from 3 mm to 15 mm, such as approximately 8 mm. The thickness or depth D of IMD 10B may range from 2 mm to 15 mm, from 5 mm to 15 mm, or from 3 mm to 5 mm, and may be any single depth or range of depths between 2 mm and 15 mm, such as approximately 4 mm. IMD 10B may have a volume of three cubic centimeters (cm) or less, or 1.5 cubic cm or less, such as approximately 1.4 cubic cm.

[0042] In the example shown in FIG. 8, once inserted subcutaneously within the patient, outer surface of cover 642 faces outward, toward the skin of the patient. In addition, as shown in FIG. 8, proximal end 646 and distal end 648 are rounded to reduce discomfort and irritation to surrounding tissue once inserted under the skin of the patient. In addition, edges of IMD 10B may be rounded.

[0043] 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, unit, or circuit for purposes of clarity, it should be understood that the techniques of this disclosure may be performed by a combination of units, modules, or circuitry associated with, for example, a medical device.

[0044] ADD HERE 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 non-transitory computer-readable 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).

[0045] ADD HERE 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” or “processing circuitry” as used herein may 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.In some examples, this disclosure describes devices and techniques for creating a reverse- lead, molded interconnect device assembly frame for accommodating an optical emitter such as a lensed light-emitting diode (LED). The device assembly frame provides a deadbug mounting arrangement for the optical emitter, configured to provide a light emission of the optical emitter, as well as a set of solder leads for the optical emitter, on a lower surface of the assembly. A device assembly frame formed according to the techniques of this disclosure may advantageously accommodate a commercial off-the-shelf (COTS) optical emitter while reducing or eliminating any light exiting the side of the device assembly frame, and providing a form factor suitable for use in an IMD.

[0046] Example 1. An implantable medical device assembly comprising: a frame configured to house an optical emitter for generating light, the frame comprising an upper surface, a lower surface, and at least one electrically-conductive path between a first pad on the lower surface and a second pad within the frame, wherein the second pad is configured for connection to an electrical terminal of the optical emitter, wherein the first pad is configured for soldering to a partially-metallized substrate with a transparent portion, to form an electrical connection between the lower surface and the substrate, and wherein the transparent portion is configured to pass at least a portion of the light generated by the optical emitter.

[0047] Example 2. The implantable medical device assembly of Example 1, wherein the optical emitter comprises a light-emitting diode (LED).

[0048] Example 3. The implantable medical device assembly of Example 1 orExample 2, wherein the frame comprises an injection molded frame.

[0049] Example 4. The implantable medical device assembly of any ofExamples 1-3, wherein the frame further comprises at least one opaque surface configured to block at least a portion of light from the optical emitter from exiting at least one side of the frame.

[0050] Example 5. The implantable medical device assembly of any of Examples 1-4, wherein the optical emitter comprises an LED having an integrated lens.

[0051] Example 6. The implantable medical device assembly of any of Examples 1-5, wherein the LED has a width of 1.6 millimeters or less and a length of 0.8 millimeters or less.

[0052] Example 7. The implantable medical device assembly of any ofExamples 1-6, wherein the transparent portion comprises a sapphire window.

[0053] Example 8. The implantable medical device assembly of any ofExamples 1-7, wherein the transparent portion comprises a transparent material capable of being metallized.

[0054] Example 9. The implantable medical device assembly of any of Examples 1-8, wherein the frame is transfer molded with a dimensional precision of at least 50 micrometers.

[0055] Example 10. The implantable medical device assembly of Example 9, wherein the frame is transfer molded with a dimensional precision of plus or minus 20 micrometers.

[0056] Example 11. A method for manufacturing an implantable medical device assembly, the method comprising: molding a frame configured to house an optical emitter for generating light, the frame comprising an upper surface, a lower surface, and at least one electrically-conductive path between a first pad on the lower surface and a second pad within the frame, wherein the second pad is configured for connection to an electrical terminal of the optical emitter, wherein the first pad is configured for soldering to a partially-metallized substrate with a transparent portion, to form an electrical connection between the lower surface and the substrate, and wherein the substrate is configured to pass at least a portion of the light generated by the optical emitter.

[0057] Example 12. The method of Example 11, further comprising providing the optical emitter as a light-emitting diode (LED).

[0058] Example 13. The method of Example 11 or Example 12, further comprising injection molding the frame.

[0059] Example 14. The method of any of Examples 11-13, further comprising mounting the optical emitter within the frame, wherein the frame is configured to direct the light generated by the optical emitter in a downward direction through the transparent portion.

[0060] Example 15. The method of any of Examples 11-14, wherein the molding comprises transfer-molding the frame using a dimensional precision of at least 50 micrometers.

[0061] Example 16. The method of Example 15, wherein the molding comprises transfer-molding the frame using a dimensional precision of plus and minus 20 micrometers.

[0062] Example 17. The method of any of Examples 11-16, further comprising arranging the frame to provide a first electrically-conductive path between a first pad on a lower surface of the frame and a second pad within the frame.

[0063] Example 18. The method of Example 17, further comprising arranging the frame to provide a second electrically-conductive path between a third pad on the lower surface of the frame and a fourth pad within the frame.

[0064] Example 19. The method of Example 18, further comprising placing the optical emitter into the frame, such that a lens portion of the optical emitter faces in a downward direction towards the lower surface, a first electrical terminal of the optical emitter contacts the second pad, and a second electrical terminal of the optical emitter contacts the fourth pad.

[0065] Example 20. The method of Example 19, further comprising soldering the first electrical terminal to the second pad, and soldering the second electrical terminal to the fourth pad.

[0066] Example 21. The method of any of Examples 18-20, further comprising arranging the frame to provide a third electrically conductive path between a fifth pad on the lower surface and a sixth pad within the frame, and a fourth electrically conductive path between a seventh pad on the lower surface and an eighth pad within the frame.

[0067] Example 22. The method of Example 21, further comprising soldering a first terminal of a second optical emitter to the sixth pad, and soldering a second terminal of the second optical emitter to the eighth pad.

Claims

WHAT IS CLAIMED:

1. An implantable medical device assembly comprising: a frame configured to house an optical emitter for generating light, the frame comprising an upper surface, a lower surface, and at least one electrically-conductive path between a first pad on the lower surface and a second pad within the frame, wherein the second pad is configured for connection to an electrical terminal of the optical emitter, wherein the first pad is configured for soldering to a partially-metallized substrate with a transparent portion, to form an electrical connection between the lower surface and the substrate, and wherein the transparent portion is configured to pass at least a portion of the light generated by the optical emitter.

2. The implantable medical device assembly of claim 1, wherein the optical emitter comprises a light-emitting diode (LED).

3. The implantable medical device assembly of claim 1 or claim 2, wherein the frame comprises an injection molded frame.

4. The implantable medical device assembly of any of claims 1-3, wherein the frame further comprises at least one opaque surface configured to block at least a portion of light from the optical emitter from exiting at least one side of the frame.

5. The implantable medical device assembly of any of claims 1-4, wherein the optical emitter comprises an LED having an integrated lens.

6. The implantable medical device assembly of any of claims 1-5, wherein the LED has a width of 1.6 millimeters or less and a length of 0.8 millimeters or less.

7. The implantable medical device assembly of any of claims 1-6, wherein the transparent portion comprises a sapphire window.

8. The implantable medical device assembly of any of claims 1-7, wherein the transparent portion comprises a transparent material capable of being metallized.

9. The implantable medical device assembly of any of claims 1-8, wherein the frame is transfer molded with a dimensional precision of at least 50 micrometers.

10. The implantable medical device assembly of claim 9, wherein the frame is transfer molded with a dimensional precision of plus or minus 20 micrometers.

11. A method for manufacturing an implantable medical device assembly, the method comprising: molding a frame configured to house an optical emitter for generating light, the frame comprising an upper surface, a lower surface, and at least one electrically- conductive path between a first pad on the lower surface and a second pad within the frame, wherein the second pad is configured for connection to an electrical terminal of the optical emitter, wherein the first pad is configured for soldering to a partially-metallized substrate with a transparent portion, to form an electrical connection between the lower surface and the substrate, and wherein the substrate is configured to pass at least a portion of the light generated by the optical emitter.

12. The method of claim 11, further comprising providing the optical emitter as a light-emitting diode (LED).

13. The method of claim 11 or claim 12, further comprising injection molding the frame.

14. The method of any of claims 11-13, further comprising mounting the optical emitter within the frame, wherein the frame is configured to direct the light generated by the optical emitter in a downward direction through the transparent portion.

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