Patent Description:
Electrochemical devices can include electrochemical sensor devices. An electrochemical sensor device can observe chemical reactions by monitoring changes in electrical properties (e.g., voltage and current). The electrochemical sensor device can be a gas sensor device for detecting gases. The electrochemical sensor device can include an electrochemical solution or material and electrodes. <CIT> discloses a gas sensor package including a housing defining a first chamber and a second chamber with the electrolyte being provided in the first chamber. <CIT> discloses an electrochemical gas sensor having a planar substrate with at least one planar electrode formed thereon and a housing defining a reservoir containing an electrolyte. <CIT> discloses a configuration for a sensor for immittance spectroscopy.

In one aspect, a gas sensor is disclosed according to claim <NUM>.

In one embodiment, the gas sensor can also include a microcontroller packaged in the housing and electrically coupled to the plurality of electrodes.

In one embodiment, the housing includes polymer or plastic.

In one embodiment, at least one of the plurality of electrodes includes conductive non-metal materials filled with carbon fiber.

In one embodiment, the gas sensor further includes conductive arms extending horizontally from the plurality of electrodes. A thickness of the electrode can be greater than a thickness of the conductive arms. The plurality of electrodes can be in electrical communication with an interconnect structure that is formed in the housing. The interconnect structures can include the conductive arms and a plurality of interconnects that extend at least partially through the lower portion from a top side of the lower portion.

In one embodiment, the housing includes a fill port that is sealed. The electrochemical solution can be disposed in the chamber through the fill port.

The access port includes a membrane that allows gas communication between the chamber and the outside environs while preventing liquid communication between the chamber and the outside environs.

In one embodiment, the lower portion of the housing further includes a cavity that is separate from the chamber. The cavity can be configured to receive an electrical component. The cavity can be configured to receive a plurality of electrical components.

In one embodiment, the plurality of electrodes include or more of carbon black, iridium black, platinum black, gold black, or ruthenium black.

In one embodiment, the housing includes polymer or plastic molded over the plurality of electrodes.

In one embodiment, the access port is configured to provide fluid communication between the chamber and the outside environs.

The access port includes a membrane that allows gas communication between the interior of the housing and the outside environs while preventing liquid communication between the interior of the housing and the outside environs.

In one embodiment, the plurality of electrodes are in electrical communication with an interconnect structure formed in the lower portion of the housing. The interconnect structures can include a plurality of interconnects extending at least partially through the lower portion from a top side of the lower portion.

In one embodiment, the lower portion of the housing further includes a cavity that is separate from the chamber. The cavity can be configured to receive an electrical component. At least a portion of the upper portion of the housing can be covered with the catalytic material.

In one aspect, a method of manufacturing a gas sensor is disclosed according to claim <NUM>.

In another aspect, a method of manufacturing a gas sensor is disclosed according to claim <NUM>.

Embodiments of this disclosure will now be described, by way of non-limiting example, with reference to the accompanying drawings.

Electrochemical devices disclosed herein may be used as sensors. For example, an electrochemical device disclosed herein can be a gas sensor. Electrochemical devices disclosed herein can be manufactured using, for example, compact packaging platforms, such as a lead frame package, a ball grid array (BGA) package, and a land grid array (LGA) package. The electrochemical device can be used in, for example, a mobile device.

An electrochemical device can include a chamber for receiving a liquid or wicking material. The chamber can receive, for example, an electrochemical material or solution (e.g., sulfuric acid). The electrochemical device can also include electrodes that are in contact with the electrochemical material. The electrodes can detect changes in electrical properties (e.g., voltage and current) of the electrochemical material due to an electrochemical material reaction. For example, the electrochemical material can react with gas. In some applications, the electrochemical device can be used to detect harmful gas (e.g., carbon monoxide) in an area.

In certain manufacturing processes, it can be difficult to manufacture relatively small electrochemical devices, and/or manufacture relatively small electrochemical devices with relatively low cost. Some electrochemical devices disclosed herein can include a housing that is at least partially defined by a molded lead frame. Such electrochemical devices with a molded lead frame can be manufactured using a relatively low cost manufacturing method, such as a molding process. Also, the molding process can be suitable for manufacturing relatively small electrochemical devices at much lower expense compared to other technologies for small electrochemical devices.

Various embodiments disclosed herein relate to an electrochemical device. In one aspect, an electrochemical device can include a housing that has an upper portion and a lower portion. The upper portion can be a first element and the lower potion can be a second element that is attached to the first element, in some embodiments. The electrochemical device can also include a chamber formed in the lower portion of the housing. The chamber can receive an electrochemical solution. In some embodiments, the electrochemical solution includes sulfuric acid, which advantageously has relatively high conductivity and water content for aiding electrochemical reactions. The electrochemical solution can react with molecules, such as gas molecules. The electrochemical solution can change its electrical properties (e.g., voltage or current) due to the reaction(s) with the molecules. In some embodiments, the electrochemical solution can react with the molecules indirectly via a catalyst. The electrochemical device can also include a plurality of electrodes formed in the upper portion of the housing. The plurality of electrodes can be exposed to the chamber. In some embodiments, the plurality of electrodes can include a sensing electrode, counter electrode, and/or a reference electrode. The plurality of electrodes can include a catalyst that react with the electrochemical solution and/or the target molecules. Oxidation and/or reduction reactions can occur at an interface between the catalyst and the electrochemical solution. The plurality of electrodes can detect or monitor the changes in electrical properties of the electrochemical solution. The monitored electrical properties can be analyzed and/or processed to determine the molecules that reacted with the electrochemical solution. The electrochemical device can further include an access port formed in the upper portion of the housing. The access port can provide fluid communication between the interior of the housing (e.g., the chamber) and the outside environs. Therefore, in some embodiments, the gas molecules can access the interior of the housing (e.g., the chamber or the electrode) through the access port.

<FIG> is a schematic top perspective view of a device <NUM> according to one embodiment. <FIG> is a schematic bottom perspective view of the device <NUM> illustrated in <FIG>. For example, the device <NUM> can be used as an electrochemical device, such as a gas sensor. The device <NUM> can include a housing <NUM> that has an upper portion <NUM> and a lower potion <NUM>. In the illustrated embodiment, the upper portion <NUM> and the lower portion <NUM> can be separate elements. For example, the upper portion <NUM> can be defined by a second element and the lower portion <NUM> can be defined by a first element that is coupled to the second element. In such embodiments, the upper portion <NUM> and the lower portion <NUM> can be bonded by an adhesive, and/or other bonding methods, such as ultrasonic bonding. The upper portion <NUM> and the lower portion <NUM> can be manufactured separately, in some embodiments.

The housing <NUM> can comprise any suitable material. In some embodiments, the housing <NUM> can comprise a molding material, such as plastic or polymer (e.g., liquid crystal polymer (LCP) or acrylonitrile butadiene styrene (ABS)). The housing <NUM> has a generally cuboid shape. However, the housing <NUM> can have any suitable shape. In some embodiments, the upper portion can comprise conductors integrated with the plastic, such as a molded metal lead frame, or a molded lead frame with conductive non-metal materials, such as conductive ABS, embedded in a non-conductive plastic mold.

The housing <NUM> of device <NUM> can have a length <NUM>, a width w1, and a height (a height h1 of the upper portion <NUM> plus a height h2 of the lower portion <NUM>). In some embodiments, the length <NUM> of the housing <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>. In some embodiments, the width w1 of the housing <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>. In some embodiments, the height h1 of the upper portion <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>. In some embodiments, the height h2 of the lower portion <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>.

The upper portion <NUM> of the housing <NUM> has a top side 12a and a bottom side 12b opposite the top side 12a. The lower portion <NUM> of the housing has a top side 14a and a bottom side 14b opposite the top side 14a. The bottom side 12b of the upper portion <NUM> and the top side 14a of the lower portion <NUM> can be coupled together. In some embodiments, the bottom side 12b of the upper portion <NUM> and the top side 14a of the lower portion <NUM> can be bonded by way of an adhesive, and/or other bonding methods, such as ultrasonic welding. In some embodiments, the top side 12a of the upper potion <NUM> can define a top side 10a of the housing <NUM>. In some embodiments, the bottom side 14b of the lower potion <NUM> can define a bottom side 10b of the housing <NUM>.

As illustrated in <FIG>, the device <NUM> includes an access port <NUM> formed in the upper portion <NUM> of the housing <NUM>. In some embodiments, the device <NUM> can include more than one access port. The access port <NUM> provides fluid communication between an interior of the device <NUM> and the outside environs. A membrane <NUM> is provided in the access port <NUM>. The membrane <NUM> allows gas to pass through while preventing liquid from passing through, thus retaining electrolyte in the cavity, while allowing analyte gases to pass.

The device <NUM> can also include a plug <NUM> that seals a fill port <NUM> (see <FIG>). The plug <NUM> can be made of the same of a different material as the material of the housing <NUM>. For example, the plug can comprise a molding material such as liquid crystal polymer (LCP) or acrylonitrile butadiene styrene (ABS). The fill port can be used for filling a filler material (e.g., an electrochemical solution) into a chamber defined in the device <NUM>. The plug <NUM> can comprise epoxy or potting materials that are compatible or non-reactive with the electrochemical solution.

As illustrated in <FIG>, the device <NUM> can also include a plurality of leads <NUM> on the bottom side 10b of the housing <NUM>. In some embodiments, the leads <NUM> can be configured to attach to a substrate (e.g., printed circuit board (PCB)), or another device, thereby connecting the device <NUM> with the substrate or the device. For example, the leads <NUM> can be formed of balls of solder material such that the bottom side 10b of the housing serves as a ball grid array (BGA) connection to lower elements of an electrical system, such as a circuit board.

<FIG> is a schematic side view of the device <NUM> illustrated in <FIG> and <FIG>. The plug <NUM> can protrude relative to the top side 10a of the housing <NUM>, in the device <NUM> illustrated in <FIG>. However, in some embodiments the plug <NUM> can be generally flush with the top side of 10a of the housing <NUM>. The leads <NUM> can protrude relative to the bottom side 10b of the housing <NUM>.

<FIG> is a schematic side view of the device <NUM> illustrated in <FIG>. As illustrated in <FIG>, the device <NUM> includes a chamber <NUM> that can be formed in the lower portion <NUM> of the housing <NUM>. The device <NUM> includes also a plurality of electrodes <NUM> that are formed in the upper portion <NUM> of the housing <NUM>. Alternatively or in addition, the plurality of electrodes <NUM> can be formed in the lower portion <NUM> of the housing <NUM>, in some examples, however, the formation of electrodes in the lower portion <NUM> is not covered by the claims. The plurality of electrodes <NUM> can be at least partially exposed to the chamber <NUM>. In some embodiments, the electrodes <NUM> can include a sensing electrode, counter electrode, and/or a reference electrode, which are provided with separate interconnects to connect each sensor to an internal or external processor. In some embodiments, the electrodes can include a circle electrode and a half-moon electrode.

In some embodiments, the chamber <NUM> can receive a filler material (e.g., an electrochemical solution). The chamber <NUM> can be fully or partially filled with the electrochemical solution. The access port <NUM> can provide fluid communication between the chamber <NUM> and the outside environs. For example, gas (e.g., carbon monoxide) can enter the chamber <NUM> through the access port <NUM>. In some embodiments, the access port <NUM> can allow gas transmission but prevent liquid transmission to keep the electrochemical solution within the device <NUM>. The gas entering into the chamber <NUM> can react with the electrochemical solution disposed in the chamber <NUM>. In some embodiments, the gas entering into the chamber <NUM> can react with the electrochemical solution disposed in the chamber <NUM> at a catalyst surface interface. The filler material can include a wicking material, which is typically a compressible material. The design of the interior surfaces of the housing can include features that compress the wicking material at the locations of the plurality of electrodes <NUM> (e.g., a surface of the catalyst of the electrodes), thereby ensuring wetting the plurality of electrodes <NUM> with the electrochemical solution. The wicking material can be applied to any of the electrodes disclosed herein.

In some embodiments, the electrochemical solution can be provided into the chamber <NUM> through a fill port <NUM> formed in the upper portion <NUM> of the housing <NUM>. Alternatively or in addition, the fill port <NUM> can be formed in the lower portion <NUM> of the housing <NUM>, in some embodiments. The fill port <NUM> can be sealed with the plug <NUM>. In some embodiments, the plug <NUM> can comprise epoxy, potting materials, or tapes with an acid compatible adhesive that are compatible or non-reactive with the electrochemical solution, after the electrochemical solution has been provided into the chamber <NUM>. In some embodiments, the electrochemical solution can be provided after the upper portion <NUM> and the lower portion <NUM> are bonded together to define the housing <NUM>. Certain bonding processes apply heat with relatively high temperature for bonding. Therefore, in some embodiments, providing the electrochemical solution into the chamber <NUM> after bonding can prevent the electrochemical solution from being heated to a relatively high temperature during the bonding process.

As explained above, the membrane <NUM> within the access port <NUM> allows gas to pass through while preventing liquid from passing through. The membrane <NUM> prevents the electrochemical solution from leaking outside of the device <NUM>. Therefore, the chamber <NUM> can be at least partially sealed by the membrane <NUM> from the outside environs while being fluidly communicative with the outside environ for gas sensing applications. The membrane <NUM> can comprise a commercially available gas-permeable and liquid impermeable membrane, such as those manufactured by W. Gore & Associates, Inc. (Newark, DE).

The plurality of electrodes <NUM> can be in contact with the electrochemical solution in the chamber <NUM>. In some embodiments, the plurality of electrodes <NUM> can be used to monitor changes in electrical properties of the electrochemical solution due to chemical reactions. The observed changes in electrical properties of the electrochemical solution can be analyzed and/or processed to determine the molecules of the gas that enter the chamber <NUM>.

In some embodiments, the plurality of electrodes <NUM> can comprise a metal lead frame (e.g., a copper lead frame), or a lead frame embedding conductive non-metallic materials, such as conductive ABS. In some embodiments, the plurality of electrodes <NUM> can be connected to an interconnect structure. The interconnect structure can include arms <NUM> that horizontally extend at least partially through the upper portion <NUM> of the housing <NUM>. The interconnect structure can include vertical interconnects (e.g., solder plugs <NUM>). The solder plugs <NUM> can extend at least partially through the lower portion <NUM> of the housing <NUM>. In some embodiments, the solder plugs <NUM> can extend through the lower portion <NUM> of the housing from the top side 14a to the bottom side 14b of the lower portion <NUM>. The leads <NUM> can be provided to the corresponding solder plugs <NUM>. In some embodiments, the leads <NUM>, such as BGA solder balls, can electrically and/or mechanically connect the solder plugs <NUM> to an external substrate (e.g., printed circuit board (PCB)) or another device.

<FIG> is a schematic top perspective view of the device <NUM> illustrated in <FIG>. <FIG> is a schematic bottom perspective view of the device <NUM> illustrated in <FIG>. The arms <NUM> that extend from the plurality of electrodes <NUM> can horizontally extend at least partially through the upper portion <NUM> of the housing <NUM> in various directions. For example, as illustrated in <FIG>, there can be three electrodes <NUM> and six arms <NUM> that extend outwardly from the three electrodes <NUM> to near edges of the housing <NUM> (e.g., between the chamber <NUM> and outer edges of the housing <NUM>). As will be better understood from illustrations described below, for metal lead frame embodiments, the arms <NUM> can represent half-etched portions of a lead frame that are embedded in molding, whereas the electrode portions and contacts (arm ends 30a) to the vertical interconnects (solder plugs <NUM>) can be thicker portions of the lead frame that are exposed by the mold material of the upper portion <NUM>. In some embodiments where conductive non-metallic materials or conductively-filled plastics are used as the electrodes <NUM>, the electrodes <NUM> and the housing <NUM> can be separately molded and bonded together, or double molded together (conductively-filled plastic can be first molded in the shape of the lead frame, and overmolded with an insulating plastic, or the insulating housing can be first molded and the conductive plastic interconnects and electrodes molded subsequently into voids in the housing). The conductive filler of the conductively-filled plastic can include, for example, carbon in the form of, for example, fibers or particles, or metal in the form of particles. The conductively-filled plastic can be applied to any of the electrodes disclosed herein in place of the metal of a conventional lead frame.

The device <NUM> can comprise a volume expansion feature <NUM>. The volume expansion feature <NUM> can accommodate volume expansion of the electrochemical solution that is disposed in the chamber <NUM>. For example, the electrochemical solution may expand when reacted with gas molecules. In some embodiments, the electrochemical solution can comprise a hygroscopic material and may change its volume due to change in, for example, humidity. For example, where the electrolyte comprises sulfuric acid, the volume may change with the ambient humidity. The expanded volume of the electrochemical solution can escape into the volume expansion feature <NUM> thereby mitigating the risk of, for example, excess pressure in the chamber, which might adversely affect the membrane <NUM> or plug <NUM>. The volume expansion feature <NUM> can comprise a recess or cavity formed on the bottom side 12b of the upper portion <NUM>. A size of the volume expansion feature <NUM> can be selected based at least in part on a difference between a volume of the electrochemical solution under maximum and minimum humidity conditions.

<FIG> is a schematic exploded view of the device <NUM> illustrated in <FIG> as seen from an angle. <FIG> is a schematic exploded view of the device <NUM> illustrated in <FIG> as seen from another angle. In some embodiments, the upper portion <NUM> and the lower portion <NUM> can comprise two separate elements. In such embodiments, the upper portion <NUM> and the lower portion <NUM> can be separately manufactured and bonded together to define the housing <NUM>. In some embodiments, the upper portion <NUM> and the lower portion <NUM> can be bonded by way of an intervening adhesive, or some other methods, such as ultrasonic welding.

The chamber <NUM> can have any suitable shape. In some embodiments, the chamber <NUM> can include one or more protrusions to compress the wicking material (when the wicking material is used). The protrusion(s) can be located on the lower portion of the chamber, opposite the electrodes <NUM>. By compressing the wicking material against the plurality of electrodes <NUM>, an improved capillary/wicking action can be provided. This way, the electrode wetting can be more consistent than the chamber <NUM> without the protrusion, independently of the electrolyte state-of-health and device orientation.

The lower portion <NUM> can comprise a plurality of through holes <NUM> for the vertical interconnects (e.g., solder plugs <NUM>). In some embodiments, the through holes <NUM> can be formed prior to providing the solder plugs <NUM>. For example, the through holes <NUM> can be formed by way of drilling. In some embodiments, the through holes <NUM> can be formed as the lower portion <NUM> is formed. For example, the vertical interconnects can be first formed and then overmolded when the lower portion <NUM> is formed, similar to the embedded lead frame of the upper portion <NUM>.

The upper portion <NUM> of the housing <NUM> can include connectors <NUM> (e.g., solder balls) on the bottom side 12b. The connectors <NUM> can be provided to corresponding ends of the arm <NUM> (see, for example, <FIG> and <FIG>). The connectors <NUM> can electrically and/or mechanically connect with the vertical interconnects (solder plugs <NUM>). In some embodiments, the connectors <NUM> can help bonding the upper portion <NUM> and the lower portion <NUM>.

<FIG> is a schematic perspective cut-away view of the device <NUM>. <FIG> is an enlarged view of a portion of <FIG>. The cross section of the device <NUM> shows the chamber <NUM> formed in the lower portion <NUM> of the housing <NUM>, the electrodes <NUM> formed in the upper portion <NUM> of the housing <NUM>, the filter <NUM> provided in the access port <NUM> formed in the upper portion <NUM>, and the plug <NUM> that seals the fill port <NUM> formed in the upper portion <NUM>.

As illustrated in <FIG> and <FIG>, the electrodes <NUM> can be at least partially exposed to the chamber <NUM>. At least a portion of the electrodes <NUM> that is not exposed to the chamber <NUM> can be embedded in the molding of the upper portion <NUM>. The arms <NUM> shown in <FIG> and <FIG> can be thinner than the electrodes <NUM> and thus embedded in the molding of the upper portion <NUM>. In some embodiments, the electrodes <NUM> can be positioned near the access port <NUM>. The electrodes <NUM> can be spaced apart by the molding material of the upper portion <NUM> of the housing <NUM>. In some embodiments, the electrodes <NUM> can be generally flush with the bottom side 12b of the upper portion <NUM>. In some embodiments, the electrodes <NUM> can protrude relative to the bottom side 12b of the upper portion <NUM>, such that at least a portion of the electrodes <NUM> is disposed within the chamber <NUM>. While not illustrated in <FIG>, it will be understood from the description below that a catalyst layer can coat the underside of the electrodes and can also coat portions of the underside of the insulating plastic of the upper portion <NUM>.

In some embodiments, the membrane <NUM> can comprise a plurality of layers. For example, the membrane <NUM> can include a membrane body <NUM> (e.g., a polytetrafluoroethylene (PTFE) membrane), adhesive layers <NUM>, and a protective layer <NUM>. In some embodiments, a cross-interference filter (not illustrated for this embodiment) can also be located at the access port outside the membrane <NUM>. One of the adhesive layers <NUM> can adhere the membrane <NUM> to the upper portion <NUM> of the housing <NUM>. In some embodiments, as illustrated, the adhesive layer <NUM> can adhere the membrane <NUM> to the top side 12a of the upper portion <NUM>. In some other embodiments, the adhesive layer <NUM> can adhere the membrane <NUM> to the bottom side 12b of the upper portion <NUM>. The adhesive layer <NUM> can be strong enough to prevent leakage of the electrochemical solution provided in the chamber <NUM>.

The plug <NUM> can seal the chamber from outside environs after disposing the electrochemical solution into the chamber <NUM>. In some embodiments, an adhesive (not illustrated) can be provided between the plug <NUM> and the upper portion <NUM> of the housing <NUM>. In some embodiments, the plug <NUM> can include an encapsulation (not illustrated) to mitigate a risk of leakage of the electrochemical solution. In some other embodiments, epoxy or potting materials that are not reactive with the electrochemical solution can be used to seal the chamber.

<FIG> is a schematic perspective view of the upper portion <NUM> of the housing <NUM> without the membrane <NUM> and the plug <NUM>. The access port <NUM> (defined in part by a central working or sensing ring electrode embedded in plastic), the fill port <NUM>, the plurality of electrodes <NUM>, and the arms <NUM> can be formed in the upper portion <NUM>. The electrodes <NUM> and the arms <NUM> can be at least partially embedded (e.g., molded) in the upper portion <NUM>.

<FIG> is a schematic perspective view of the upper portion <NUM> and the connectors <NUM> (e.g. solder balls). The connectors <NUM> can be provided to corresponding ends 30a of the arms <NUM> shown in <FIG>. In some embodiments, the ends 30a of the arms <NUM> and/or the electrodes <NUM> can be coated with a protective layer (e.g., a gold layer). The gold layer can help prevent the base material of lead frame that forms the arm and the electrodes from oxidation. In some embodiments, a coating material can comprise catalyst. In some embodiments, the electrodes <NUM> can be aluminum or copper base material coated with a catalytic material such as carbon black, iridium black , a platinum black gold black, and/or ruthenium black. The catalytic material can enhance the performance of the electrode <NUM>, in some applications. In some embodiments, different coating material(s) can be selected based at least in part on the gas(es) interested to be sensed. The coating material can be coated on the electrodes <NUM> in any suitable manner. For example, a coating material (e.g., platinum black) can be coated on the electrodes <NUM> by way of screen printing or stencil printing. In such processes, the coating material can be applied as an ink and can be applied over both the undersides of the electrodes and the insulating plastic of the upper part <NUM> after assembly of the upper part (including placement of the membrane <NUM> illustrated below). The ink can include hydrophobic particles, such as polytetrafluoroethylene (PTFE) or the line materials. The catalytic layer is illustrated below as the lowest layer of the electrodes exposed to the cavity, for example, in <FIG> and <FIG>, among others. The Catalyst layer can be applied in any of the embodiments disclosed herein. Though the catalyst material is not illustrated with the plurality of electrodes <NUM> in <FIG>, the catalyst material can be provided for the electrodes <NUM> as illustrated and described in various embodiments disclosed herein. The catalyst material can be coated onto the inner surface of the housing in illustrated embodiments, including <FIG>, after assembly of the upper portion of the housing, including the membrane and the filter (if present). The timing of the coating is such that the catalytic material individually coats each electrically separate electrode along with surrounding portions of insulating mold material. In the case of the working or sensing electrode, the catalytic coating can also cover and contact the membrane, ensuring contact of the analyte gas with the catalytic coating that serves as the working electrode.

<FIG> is a schematic top perspective view of a lead frame <NUM> that includes the electrodes <NUM> and arms <NUM>, according to one embodiment. In some embodiments, the lead frame <NUM> can comprise a copper lead frame. In some embodiments, the lead frame <NUM> can comprise a conductive plastic lead frame. The conductive plastic lead frame can include a lead frame that comprises plastic (e.g., liquid crystal polymer (LCP) or acrylonitrile butadiene styrene (ABS)) and carbon fiber. In some embodiments, the carbon fiber or other conductive filler material can be mixed, embedded, or otherwise integrated with the plastic. <FIG> is a schematic bottom perspective view of the lead frame <NUM> illustrated in <FIG>. The lead frame <NUM> can be at least partially embedded (e.g., molded) in the upper portion <NUM> of the housing <NUM>. In some embodiments, the electrode <NUM> can have a curvature. For example, the electrode <NUM> can have a round shape, a half-moon shape, and/or a circular shape. In some embodiments, a curved electrode can provide a shorter path through the electrolyte between electrodes (a first electrode and a second electrode) than with an electrode without curvature. When the path between the electrodes is shorter, there can be less resistance than with a longer path between the electrodes, thereby enhancing the accuracy of measurement of changes on electrical properties in the device.

The arms <NUM> of the lead frame <NUM> have a width w2. In some embodiments, the width w2 can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>. The arms <NUM> of the leadframe <NUM> have a thickness t1 between the electrodes <NUM> and the ends 30a of the arms <NUM>. The ends 30a of the arms <NUM> have a thickness t2. The electrodes <NUM> of the lead frame <NUM> have a thickness t3. In some embodiments, the thickness t1 of the arms <NUM> can be less than the thickness t2 of the ends 30a and/or the thickness t3 of the electrodes <NUM>. Such an arrangement can be achieved by half-etching the arms <NUM> during lead frame fabrication so that they may be embedded during molding in polymer, such as LCP or ABS. In some embodiments, the thickness t1 of the arms <NUM> can be less than seventy percent (<NUM>%), between twenty percent (<NUM>%) to seventy percent (<NUM>%), or between forty percent (<NUM>%) to sixty percent (<NUM>%), of the thickness t2 of the ends 30a and/or the thickness t3 of the electrodes <NUM>. For example, the thickness t1 of the arms <NUM> can be about fifty percent (<NUM>%). In some embodiments, the thickness t1 of the arms <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>. In some embodiments, the thickness t2 of the ends 30a of the arms <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>. In some embodiments, the thickness t3 of the electrodes <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>. As noted above, the electrodes <NUM> also include a catalytic layer (not shown in <FIG>), such that the thicker portions of the lead frame <NUM> shown in <FIG> and <FIG> may be viewed as contacts for catalytic electrodes.

<FIG> is a schematic top perspective view of a device <NUM> according to one embodiment. <FIG> is a schematic bottom perspective view of the device <NUM> illustrated in <FIG>. <FIG> is a schematic side view of the device <NUM> illustrated in <FIG> and <FIG>. Unless otherwise noted, components of the device <NUM> may refer to components that are the same as or generally similar to like components of the device <NUM>. The device <NUM> is generally similar to the device <NUM>. Instead of having a BGA structure of device <NUM>, the device <NUM> has a land grid array (LGA) structure. In other words, instead of having the BGA balls as the leads <NUM> on the bottom side 10b of the housing <NUM>, the device <NUM> comprises a plurality of LGA pads <NUM> that are exposed on the bottom side 10b of the housing <NUM>.

The device <NUM> can include a housing <NUM> that has an upper portion <NUM> and a lower portion <NUM>, an access port <NUM> formed in the upper portion <NUM> of the housing <NUM>, a chamber <NUM> formed in the lower portion <NUM> of the housing <NUM>, and a plurality of electrodes <NUM> formed in the upper portion <NUM> of the housing <NUM>. The device <NUM> can also include a membrane <NUM> in a topside recess surrounding the access port <NUM>. The device can also include a plug <NUM> that can seal a fill port <NUM>. The plug <NUM> can protrude relative to the top side 10a of the housing <NUM>. However, in some embodiments the plug <NUM> can be generally flush with the top side of 10a of the housing <NUM>. Alternatively, the plug can comprise epoxy or potting materials that are compatible or non-reactive with the electrochemical solution. The bottom side 10b of the housing <NUM> can be generally planar.

Interconnects <NUM> can be formed in the lower portion <NUM> of the housing <NUM>. In some embodiments, the interconnects <NUM> can extend through the lower portion <NUM> of the housing <NUM> from the top side 14a to the bottom side 14b of the lower portion <NUM>. The exposed portion of the interconnects <NUM> on the bottom side 14b of the lower portion <NUM> can define the LGA pads <NUM>. In some embodiments, the LGA pads <NUM> can be coated with a protective layer (e.g., a gold layer). The embodiment of <FIG> can be otherwise similar to the embodiment of <FIG>.

<FIG> is a schematic top perspective view of a device <NUM> according to one embodiment. <FIG> is a schematic bottom perspective view of the device <NUM> illustrated in <FIG>. <FIG> is a schematic bottom perspective view of the device <NUM> illustrated in <FIG> and <FIG> without a seal plate <NUM> and without the catalytic layers coating the electrodes and covering the access port <NUM>. <FIG> is a schematic side view of the device <NUM> illustrated in <FIG> and <FIG>. Unless otherwise noted, components of the device <NUM> may refer to components that are the same as or generally similar to like components of the devices <NUM> and <NUM>. Instead of having a BGA structure of device <NUM> or a LGA structure of device <NUM>, the device <NUM> comprises a dual flat package (DFP) structure. In other words, instead of having the solder plugs and the BGA balls as the leads <NUM> (<FIG>) or the interconnects <NUM> and the LGA pads <NUM> (<FIG>), the device <NUM> comprises leads formed by legs <NUM> that extend from the housing <NUM>'.

The device <NUM> can include a housing <NUM>' that has an upper portion <NUM>' and a lower portion <NUM>', an access port <NUM> formed in the upper portion <NUM>' of the housing <NUM>', a chamber <NUM>' formed in the lower portion <NUM>' of the housing <NUM>', and a plurality of electrodes <NUM> formed in the upper portion <NUM>' of the housing <NUM>'. The device <NUM> can also include a membrane <NUM> and a filter (not shown) in the access port <NUM>. The device can also include a plug <NUM> that can seal a fill port <NUM>. The plug <NUM> can protrude relative to the top side 10a' of the housing <NUM>'. However, in some embodiments the plug <NUM> can be generally flush with the top side of 10a' of the housing <NUM>'. The bottom side 10b' of the housing <NUM>' can be generally planar. Alternatively, the plug <NUM> can comprise epoxy or potting materials that are compatible or non-reactive with the electrochemical solution. The device <NUM> can also include the seal plate <NUM>.

The upper portion <NUM>' and the lower potion <NUM>' of the housing <NUM>' can be monolithically formed. In some embodiments the upper portion <NUM>' and at least part of the lower portion <NUM>' can be manufactured by a single molding process. The lower portion <NUM>' can include the seal plate <NUM> as a separate piece that can at least partially seal the chamber <NUM>' from the outside environs.

The legs <NUM> can extend from the upper portion <NUM>' of the housing <NUM>'. The legs <NUM> can be connected to the arms <NUM>' and indeed can be integrally formed from the same lead frame. The legs <NUM> can be configured to connect to an external substrate (e.g., a printed circuit board (PCB)) or an external device. In some embodiments, the arms <NUM>' and the legs <NUM> can provide electrical pathway between the electrodes <NUM> and the external substrate or the external device. Advantageously, all conductors for routing signals to and from the electrodes <NUM> can be integrally formed by a single lead frame separate conductors and attendant fabrication steps for the lower portion <NUM>' can be omitted.

<FIG> is a schematic top perspective view of a device <NUM> according to one embodiment. <FIG> is a schematic bottom perspective view of the device <NUM> illustrated in <FIG>. Unless otherwise noted, components of the device <NUM> may refer to components that are the same as or generally similar to like components of the devices <NUM>, <NUM>, and <NUM>. The device <NUM> can include a housing <NUM> that has an upper portion <NUM> and a lower portion <NUM>, an access port <NUM> formed in the upper portion <NUM> of the housing <NUM>, a plug <NUM> that can seal a fill port <NUM> (see <FIG>) formed in the upper portion <NUM>, and a printed circuit board assembly (PCBA) <NUM>. The housing <NUM> can be coupled to a top side 68a of the PCBA <NUM>. The PCBA <NUM> can have contact pads <NUM> at a bottom side 68b of the PCBA <NUM>. In some embodiments, the device <NUM> can be configured to fit in a micro subscriber identification module (SIM) card socket.

<FIG> is a schematic top perspective view of the device <NUM> with internal components of the device <NUM>. <FIG> is a schematic bottom perspective view of the device <NUM> with the lower portion <NUM> and the dielectric portions of the PCBA <NUM>. The device <NUM> can also include a membrane <NUM> formed in the upper portion <NUM> of the housing <NUM>, a plurality of electrodes <NUM> formed in the upper portion <NUM>, a chamber <NUM> formed in the upper part of the lower portion <NUM>, and a cavity <NUM> formed in the lower part of the lower portion <NUM>. In some embodiments, the membrane <NUM> can include an adhesive layer.

The upper portion <NUM> can be provided as a molded lead frame. The electrodes <NUM> can be exposed to the chamber <NUM>. The chamber <NUM> can receive an electrochemical solution. The electrochemical solution can be disposed into the chamber <NUM> through the fill port <NUM>. The fill port <NUM> can be sealed by way of the plug <NUM>. Alternatively, the plug can comprise epoxy or potting materials that are compatible or non-reactive with the electrochemical solution. The access port <NUM> can provide fluid communication between the chamber <NUM> and the outside environs through a gas-permeable and liquid impermeable membrane and a catalytic layer.

The chamber <NUM> and the cavity <NUM> can be formed at different locations of the second portion <NUM>. In some embodiments, the chamber <NUM> can be formed at the top side 64a of the lower portion <NUM>, and the cavity <NUM> can be formed at the bottom side 64b of the lower portion <NUM>. The cavity <NUM> can be configured to receive components disposed on the PCBA <NUM>, such as processors and/or passive electronic components (e.g., resistors, capacitors, etc.). For example the PCBA can include a precision analog microcontroller with chemical sensor interface (e.g., ADuCM355 manufactured by Analog Devices Inc. The lower portion <NUM> can also include interconnects <NUM> that extend at least partially through the lower portion <NUM> from the top side 64a. In some embodiments, the interconnects <NUM> can extend through the lower portion <NUM> from the top side 64a to the bottom side 64b.

In some embodiments, the PCBA <NUM> can include a printed circuit board (PCB) <NUM> and a plurality of components <NUM> disposed on the PCB. The components <NUM> can include passive components and/or active components. In some embodiments, the components <NUM> can process data acquired through the electrodes <NUM>. In some embodiments, one or more of the components <NUM> can be electrically connected through an interconnect structure. The interconnect structure can include lead frame arms <NUM> that horizontally extends at least partially through the upper portion <NUM>, and the interconnects <NUM>. In some embodiments, ends 88a of arms <NUM> can be exposed on the bottom side <NUM> of the upper portion <NUM>. In some embodiments, the interconnect structure can also include a trace (not illustrated) formed in or on the PCB <NUM>.

<FIG> is a schematic exploded view of the device <NUM> illustrated in <FIG> as seen from above. <FIG> is a schematic exploded view of the device <NUM> illustrated in <FIG> as seen from below. The lower portion can comprise holes <NUM> for receiving the interconnects <NUM>. In some embodiments, solder balls <NUM> can be provided to connect the interconnects <NUM> and pads <NUM> on a top side 84a of the PCB <NUM>. The upper portion <NUM> can comprise a volume expansion feature <NUM>, as explained above.

The bottom side 62b of the upper portion <NUM> can comprise a coating material <NUM>. In some embodiments, the coating material <NUM> can comprise a catalyst such as carbon black, iridium black, platinum black gold black, and/or ruthenium black. Thus, the electrodes <NUM> can include the conductors of the lead frame coated with catalytic material. The catalytic layer can enhance the performance of the electrode <NUM>, in some applications. In some embodiments, different coating material(s) <NUM> can be selected based at least in part on the gas(es) interested to be sensed. The coating material <NUM> can be coated on the electrodes <NUM> in any suitable manner. For example, the coating material <NUM> (e.g., platinum black) can be coated on the electrodes <NUM> and the plastic underside of the upper portion <NUM> of the housing by way of screen printing or stencil printing. In such processes, the coating material <NUM> can be applied as an ink. The ink can include hydrophobic particles, such as polytetrafluoroethylene (PTFE) or the line materials. The catalytic coating material <NUM> can also cover the underside of the membrane <NUM> that communicates with the access port <NUM>.

<FIG> is a schematic perspective cut-away view of the device <NUM>. The cross section of the device <NUM> includes the chamber <NUM> formed at the top side 64a of the lower portion <NUM>, the electrodes <NUM> formed in the upper portion <NUM>, a cavity <NUM> formed at the bottom side 64b of the lower portion <NUM>, and the plug <NUM> that seals the fill port <NUM> formed in the upper portion <NUM>. In some embodiments, the cavity <NUM> can have varying depths or heights for receiving different components having different heights.

<FIG> is a bottom plan view of the upper portion <NUM> of the device <NUM> without the plug <NUM>. <FIG> is a schematic perspective view of the upper portion <NUM> illustrated in <FIG> with the molding of the upper portion <NUM>. The upper portion <NUM> can include the membrane <NUM>, the electrodes <NUM>, the arms <NUM> that extends from the electrodes <NUM> having arm ends <NUM>', the fill port <NUM>, and a volume expansion feature <NUM>. In some embodiments, as illustrated, the electrodes <NUM> can include the coating material <NUM> (such as carbon black), and the coating material <NUM> can also cover the membrane <NUM>. In some embodiments, the ends <NUM>' of the arms <NUM> can be coated with a protective layer (e.g., a gold layer). As in the prior embodiments, the arms <NUM> can be half-etched portions of a lead frame, while the arm ends <NUM>' and electrodes <NUM> represent unetched thicker portions of the lead frame, or a conductively-filled plastic can be molded in these shapes.

<FIG> is a schematic perspective view of the membrane <NUM> according to one embodiment. The membrane <NUM> can include an adhesive layer <NUM> and a membrane body <NUM>. The membrane <NUM> can also include a protective layer (not illustrated). The dimension of the membrane <NUM> can be selected such that the filter effectively seals the chamber <NUM> when provided in the upper portion <NUM>. The membrane <NUM> can also be embedded in the mold (e.g., LCP or ABS) of the molded lead frame that defines the upper portion <NUM>.

The membrane <NUM> has a diameter d1. In some embodiments, the diameter d1 of the membrane <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>. The membrane <NUM> has a thickness t4. In some embodiments, the thickness t4 of the membrane <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>.

The adhesive layer <NUM> has an inner diameter d2. In some embodiments, the inner diameter d2 of the adhesive layer <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>.

The adhesive layer <NUM> has a thickness t5. In some embodiments, the thickness t5 of the adhesive layer <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>.

The membrane body <NUM> has a thickness t6. In some embodiments, the thickness t6 of the membrane body <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>.

<FIG> is a schematic top plan view of a lead frame structure <NUM> that can be included in any devices discloses herein. <FIG> is a schematic side view of the lead frame structure <NUM> illustrated in <FIG>. <FIG> is a schematic bottom perspective view of the lead frame structure <NUM> illustrated in <FIG> and <FIG>. The lead frame structure <NUM> can have similar functionality as the lead frame <NUM>. The lead frame structure <NUM> can comprise the plurality of electrodes <NUM> (thicker portions of the lead frame structure <NUM> in ring and arc shapes, as best seen in <FIG>), and the arms <NUM> that extend from the electrodes <NUM>. In some embodiments, the ends 88a of the arms <NUM> and/or the electrodes <NUM> can be coated with a protective layer (e.g., a gold layer). In some embodiments, the electrodes <NUM> can be coated with a carbon black layer, an iridium black layer, a platinum black layer gold black, ruthenium black or a mixture of such catalytic materials, such that the illustrated electrodes <NUM> can be considered contacts to electrodes formed by the catalytic layer.

<FIG> is a schematic perspective view of a system in package (SiP) <NUM> that can be used with any of the devices disclosed herein, according to one embodiment. <FIG> is a schematic bottom plan view of the SiP <NUM> illustrated in <FIG>. <FIG> is a schematic perspective view of the SiP <NUM> with an overmold <NUM>.

The SiP <NUM> includes a substrate <NUM> (e.g., a laminate substrate), components <NUM> disposed on the substrate <NUM>, and the overmold <NUM> over the components <NUM>. In some embodiments, the components <NUM> can include stacked dies. For example, a first die <NUM> can be mounted on a top side of the substrate <NUM>, and a second die <NUM> can be mounted on the first die <NUM>. In some embodiments one or more of the components <NUM> of the SiP <NUM> can analyze, process, and/or pre-process the monitored changes in electrical properties (e.g., voltage or current) of the electrochemical solution. In such embodiments, the one or more of the components <NUM> of the SiP <NUM> can connect to the electrodes in the device.

The SiP <NUM> can comprise contact pads <NUM> on a bottom side of the SiP <NUM>. The number, the shape, and/or the locations of the contact pads <NUM> can vary. In some embodiments, the contact pads <NUM> can be distributed symmetrically or asymmetrically on the bottom side of the SiP <NUM>. In some embodiments, sizes of the contact pads <NUM> can vary. The contact pads <NUM> have a width w3, and a length l2. In some embodiments, the contact pads <NUM> can comprise square pads. In such embodiments, the width w3 and the length l2 can be the same. In some embodiments, the width w3 of a contact pad <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>. In some embodiments, the length l2 of a contact pad <NUM> can be in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, in a range of, for example, <NUM> to <NUM>, or in a range of, for example, <NUM> to <NUM>.

<FIG> is a schematic top perspective view of a device <NUM> according to one embodiment. <FIG> is a schematic bottom perspective view of the device <NUM> illustrated in <FIG>. <FIG> is a schematic top perspective view of the device <NUM> with the mold material of a housing <NUM>. <FIG> is a schematic bottom perspective view of the device <NUM> with the mold material of the housing <NUM>. <FIG> is a schematic perspective cut-away view of the device <NUM>. <FIG> is a schematic perspective view of a different cut-away of the device <NUM>. Unless otherwise noted, components of the device <NUM> may refer to components that are the same as or generally similar to like components of the devices <NUM>, <NUM>, <NUM>, and <NUM>.

The device <NUM> can include a housing <NUM> that has an upper portion <NUM> and a lower portion <NUM>. The device <NUM> can also include an access port <NUM> formed in the upper portion <NUM>, a membrane <NUM> in the access port <NUM> at or near a bottom side 132b of the upper portion <NUM>, a filter <NUM> in the access port <NUM> at or near a top side 132a of the upper portion <NUM>, a first fill port 140a and a second fill port 140b formed in the upper portion <NUM>, and a first plug 142a and a second plug 142b in the respective fill ports 140a, 140b. The bottom side 132b of the upper portion <NUM> can comprise a coating material <NUM>. In some embodiments, the coating material <NUM> can comprise catalyst. The device <NUM> can comprise contact pads <NUM> on a bottom side 134b of the lower portion <NUM>. The contact pads can be made, in some embodiments, by molded interconnect method that involves selective laser ablation followed by electroless plating of conductive materials, such as Ni/Au. The device <NUM> can include a plurality of electrodes <NUM> formed in the upper portion <NUM>, and arms <NUM> that horizontally extend at least partially through the upper portion <NUM>. The upper portion can be formed as a molded lead frame, with the lead frame providing the electrodes <NUM> and arms. Alternatively, the electrodes can be made of conductive non-metal materials, such as conductive ABS.

The device <NUM> can include a chamber <NUM> formed in the lower portion <NUM> of the housing <NUM>, and a cavity <NUM> formed in the lower portion <NUM>. In some embodiments, the chamber <NUM> can receive an electrochemical solution. In some embodiments, the cavity <NUM> can receive components, such as processors and/or passive components. In some embodiments, the cavity can receive system in package (SiP) <NUM>. SiP can also be overmolded into the lower portion <NUM> instead of being put into a pre-made cavity.

In some embodiments, the electrochemical solution can be provided into the chamber <NUM> through the first fill port 140a or the second fill port 140b formed in the upper portion <NUM> of the housing <NUM>. The first fill port 140a and the second fill port 140b can be generally similar to the fill ports <NUM>, <NUM> described above. However, in the device <NUM>, one of the two fill ports 140a, 140b can act as a vent hole. For example, the electrochemical solution can be injected from one of the fill ports (e.g., the first fill port 140a) and the other fill port (the second fill port) can act as a vent hole.

<FIG> is a schematic exploded view of the device <NUM> illustrated in <FIG> as seen from above. <FIG> is a schematic exploded view of the device <NUM> illustrated in <FIG> as seen from below. <FIG> is a schematic perspective view of the lower portion <NUM> of the device <NUM> illustrated in <FIG>. <FIG> is a schematic bottom plan view of the lower portion <NUM> illustrated in <FIG>. <FIG> is a schematic side view of the lower portion <NUM> illustrated in <FIG> and <FIG> with the molding. <FIG> is a schematic bottom plan view of the upper portion <NUM> of the device <NUM> illustrated in <FIG>. <FIG> is a schematic perspective view of the upper portion <NUM> illustrated in <FIG>. <FIG> is a schematic side view of the upper portion <NUM> illustrated in <FIG> and <FIG>. <FIG> is a schematic perspective view of the membrane <NUM> of the device <NUM> illustrated in <FIG>. <FIG> is a schematic perspective view of the filter <NUM> of the device <NUM> illustrated in <FIG>.

In some embodiments, the membrane <NUM> can comprise a plurality of layers. For example, the membrane <NUM> can include a membrane body or a hydrophobic layer <NUM> (e.g., PTFE) and adhesive layer <NUM>. In some embodiments, the adhesive layer <NUM> can adhere the membrane <NUM> to the upper portion <NUM> of the housing <NUM> over the access port <NUM>. In the illustrated embodiment, the adhesive layer <NUM> can adhere the membrane <NUM> to a recess formed at the bottom side 132b of the upper portion <NUM> and over the access port <NUM>. In some other embodiments, the adhesive layer <NUM> can adhere the membrane <NUM> to the upper side 132a of the upper portion <NUM> over the access port <NUM>. The adhesive layer <NUM> can seal the membrane <NUM> over the access port <NUM> to prevent leakage of the electrochemical solution provided in the chamber <NUM>. In other embodiments, the membrane <NUM> can be fixed to the housing over the access port <NUM> without a separate adhesive layer, such as by welding or heat treatment.

The filter <NUM> can include a filter layer <NUM> and an adhesive layer <NUM>. The adhesive layer <NUM> can adhere the filter layer <NUM> to a recess formed in the upper portion <NUM> of the housing <NUM> and over the access port <NUM>. In some embodiments, the access port <NUM> can be structured such that when the filter <NUM> is placed in the access port <NUM>, the top side 132a of the upper portion <NUM> can be generally planar. The filter layer <NUM> can comprise any suitable materials. The filter <NUM> can include any suitable additional layers. In some applications, the filter <NUM> can filter unwanted materials that might interfere with detection of the gas(es) of interest. In some embodiments, the filter <NUM> can comprise activated carbon that can react with alcohol (e.g., adsorb alcohol). In some embodiments, the filter <NUM> can comprise activated woven carbon cloth. For example, the activated woven carbon cloth can be Flexzorb™ ACC, manufactured by Chemviron, for all of the embodiments herein that include a filter.

In some embodiments, the lower portion <NUM> can include a plurality of holes <NUM> for conductive plugs <NUM>. The conductive plugs <NUM> can comprise, for example, a solder plug or a conductive epoxy plug. The conductive plug <NUM> can be connected to ends 147a of the arms <NUM> formed in the upper portion <NUM>.

<FIG> is a schematic top plan view of a lead frame structure <NUM> according to one embodiment. <FIG> is a schematic side view of the lead frame structure <NUM> illustrated in <FIG>. <FIG> is a schematic bottom perspective view of the lead frame structure <NUM> illustrated in <FIG> and <FIG>. The lead frame structure <NUM> can comprise the plurality of electrodes <NUM>, and the arms <NUM> that extends from the electrodes <NUM>. In some embodiments, the ends 147a of the arms <NUM> and/or the electrodes <NUM> can be coated with a protective layer (e.g., a gold layer). In some embodiments, the electrodes <NUM> can be coated with a carbon black or other catalyst layer. In some embodiments, the lead frame structure <NUM> can comprise various metal materials, such as copper, stainless steel, etc. In some embodiments, the lead frame structure <NUM> can comprise conductive non-metal materials, such as conductive ABS.

The devices disclosed herein can be manufactured using any suitable methods. A method of manufacturing a device as defined by claims <NUM> or <NUM>, includes fabricating a housing that has an upper portion and a lower portion. The method can include fabricating a lead frame that has a plurality of electrodes and arms extending from the electrodes. Fabricating the housing includes a molding process, for example, single or double shots molding. In some embodiments, fabricating the lead frame can include providing a conductive plastic material in voids or grooves formed in a the housing. In some embodiments, the housing can be defined by a molding material (e.g., liquid crystal polymer (LCP) or acrylonitrile butadiene styrene (ABS)). Fabricating the housing can include ovemolding the lead frame (metal or conductively-filled plastic) by a molding material (e.g., LCP or ABS). In some embodiments, fabricating the housing can include providing the upper portion (e.g., a first element) and providing the lower portion (e.g., a second element). The lower portion can have a chamber configured to receive an electrochemical solution. The upper portion can have a plurality of electrodes, an access port, and/or a fill port. In some embodiments, fabricating the housing can include bonding the upper potion and the lower portion. In some embodiments the upper portion and the lower portion can be bonded by way of an adhesive. In some embodiments, the upper portion and the lower portion can be monolithically formed. In some embodiments, fabricating the housing can include providing a seal plate configured to seal the chamber.

The method includes also providing a membrane and optionally also a filter to the access port. The membrane allows gas communication between the chamber and the outside environs while preventing liquid communication between the chamber and the outside environs. In some embodiments, the membrane can be attached to the housing by way of an adhesive, ultrasonic welding, or thermal welding.

In some embodiments, the method can also include filling an electrochemical solution into the chamber. The electrochemical solution can be filled into the chamber through the fill port. The fill port can be sealed by way of a plug, and/or epoxy, potting materials.

In some embodiments, the method can also include forming an interconnect structure in the device. For example, the lower potion can include a through via (e.g., through mold via) that can at least partially provide interconnection between the plurality of electrodes to an external substrate or an external device.

Claim 1:
A gas sensor (<NUM>) comprising:
a housing (<NUM>) having an upper portion (<NUM>) and a lower portion (<NUM>);
a chamber (<NUM>) formed in the lower portion (<NUM>) of the housing (<NUM>), the chamber (<NUM>) configured to receive an electrochemical solution;
a plurality of electrodes (<NUM>) formed in the upper portion (<NUM>) of the housing; the plurality of electrodes (<NUM>) molded in the upper portion (<NUM>) of the housing and at least partially exposed to the chamber (<NUM>);
an access port (<NUM>) formed in the upper portion (<NUM>), the access port (<NUM>) configured to provide fluid communication between an interior of the housing and the outside environs,
wherein the access port (<NUM>) comprises a membrane (<NUM>) that allows gas communication between the chamber and the outside environs while preventing liquid communication between the chamber and the outside environs.