Patent Description:
Conventional techniques for making electronic devices water-resistant or waterproof typically involve a cover placed on or around an electronic device housing after the electronic device has been assembled. These conventional techniques provide numerous shortcomings, such as lack of protection from accidental liquid encounters when not in place, failure to provide device protection from solid particles (e.g., dust) when not in place, bulky form factors that reduce device functionality, failure to provide device protection if not installed correctly by an end user, disabling functionality and accessibility of device ports such as a headphone jack or power connector, and so forth.

Other conventional techniques involve water-resistant surface treatments applied to electronic devices. One example of a conventional water-resistant surface treatment includes applying a polymeric coating formed by exposing the electronic device to static or pulsed plasma for a sufficient period of time to allow a polymeric layer to form on the surface of the electronic device. In another example, a coating comprising halo-hydrocarbon polymers is applied on a PCB and a board assembly by plasma etching, plasma activation, plasma polymerization and coating, and/or liquid-based chemical treatment. In yet another example, waterproof bulk conformal coatings are used in automotive electronic assemblies, and parylene films can be used to coat small devices, such as hearing aids using a highly reactive vapor phase precursor generated by pyrolysis of a solid.

However, conventional techniques for water-resistant surface treatments applied to electronic devices are not without limitations. First, surface treatment-induced high impedance, open circuit, or intermittent function of movable electronic contacts result in both component- and system-level functional failure of the electronic device. Additionally, plasma processing of a fluorohydrocarbon precursor often results in low process yields because fluorohydrocarbon molecules are large, unable to diffuse through a reticulated structure of substrate assemblies of electronic devices, and molecular fragments created by the plasma processing do not readily wet the surfaces of substrate assemblies, thus preventing complete encapsulation of the substrate assemblies. Further, electronic devices have interconnects, such as board-to-board (BTB), zero insertion force (ZIF) connectors, universal spring contacts, pogo pin contacts, dome switch assemblies, SIM and SD card readers, and so forth.

Failures of these interconnects typically results from contamination of an electrical contact zone in an interconnect from application of a water-resistant surface treatment, or mechanical disruption of the water-resistant surface treatment due to mechanical shock or mechanically disconnecting the interconnect during device rework. Interconnect failures are especially prevalent when the water-resistant surface treatment is a film with a thickness greater than <NUM>, and large molecular weight films such as parylene and cross-linked fluroacrylates. These conventional techniques thus require compromises to a film's water resistance or laborious masking of contacts, and result in significant reduction in achieved water resistance, increasing manufacturing complexity and cost, and ultimately do not provide the intended goal of waterproofing or sufficiently water resisting electronic devices.

<CIT> discloses a process for water-proofing devices from the inside out, the process is suited for application to completely fabricated electronic devices to enable them to be used with full functionalities in and under the water and in a variety of aquatic environments, shockproof and corrosion resistant. Multilayer technology fills empty spaces in the electronic device with a first layer of a hydrophobic medium like silicone and then a second layer of an anti-corrosive agent. Creating a vacuum removes air from the insulating mediums, slowly eliminating the vacuum to allow air to push the mediums into the device's internal voids, and then curing while preserving button functionality and patency of electronic pathways. <CIT> discloses UV curable compositions suitable for use as potting and encapsulating compounds for electrical and electronic devices. The compositions comprise: (a) a UV curable compound polymerizable by a free radical process and containing reactive unsaturated groups, (b) a polysilane photo-initiator, and (c) a peroxide photo-initiator. The use of the two photo-initiators enables one to get a more complete cure, both at the surface and deep into the coating. The technical article "<NPL>, available on the Electrolube website, describes various resins for use in potting and encapsulation.

Implementations of device component exposure protection are described with reference to the following Figures. The same numbers may be used throughout to reference similar features and components shown in the Figures:.

Implementations of device component exposure protection are described, and provide techniques for waterproof and/or water-resistant protection of electronic devices, such as during device manufacture, without the need for after-market, bulky exterior casings. A protective material fills void spaces around device components within a housing of an electronic device during device assembly, providing protection to internal components of the device from water, dust, contact, and other environmental hazards.

In aspects of device component exposure protection, a computing device includes device components enclosed within a housing, such as a mobile device or mobile phone, a tablet device, a laptop computing device, a digital camera, and so forth. The device components can be assembled and enclosed within the housing upon completion of assembly of the computing device. The computing device further includes a protective material contained within the housing, which fills void spaces around the device components. The void spaces around the device components are filled with the protective material, which prevents exposure of the device components to external matter that the computing device is exposed to upon completion of the assembly. The protective material, includes low-modulus elastomers (LME), thermoplastics (TP), and one or more combinations of LME and TP. The protective material protects the device components from external matter that may enter into the housing of the device, such as water, dust, and other materials present in an environment of the device. The device components are protected from the inside-out of the computing device. The features of device component exposure protection described herein can be integrated into device assembly and repair techniques with minimal adaptations, and provide device users with a device protected from environmental hazards without the need for after-market, bulky device add-ons that cover the exterior of a device.

While features and concepts of device component exposure protection can be implemented in any number of different devices, systems, environments, and/or configurations, implementations of device component exposure protection are described in the context of the following example devices, systems, and methods.

<FIG> illustrates an example <NUM> of a computing device <NUM> shown at various stages of assembly <NUM>, <NUM>, <NUM>, and <NUM> that illustrate the techniques of device component exposure protection as described herein. In this example, the computing device <NUM> may be any type of computing device, such as a mobile phone, tablet, laptop computer, desktop computer, computer accessory (e.g., keyboard, mouse, headphones, webcam, etc.), wearable electronic device (e.g., watch, glasses/goggles, microphone, etc.), and so forth. Generally, the computing device <NUM> is implemented with various components such as a processing system and memory, as well as any number and combination of different components as further described in reference to the example device shown in <FIG>.

In aspects of device component exposure protection, the computing device <NUM> includes device components <NUM> enclosed within a housing <NUM>. The device components <NUM> include a substrate assembly <NUM> with various components attached to the substrate assembly. The substrate assembly <NUM> may include any type of substrate, such as those used for attaching integrated circuits within the computing device <NUM>, for example a ceramic substrate, a glass substrate, a silicone substrate, a polyimide substrate, a printable circuit board (PCB), and so forth. The substrate assembly <NUM> provides a base to support electronic components <NUM> (and non-electronic computing device components), such as integrated circuits, electronic subassemblies, capacitors, resistors, and similar devices, along with providing connection paths to electrically connect the electronic components to form electrical circuits, which are used for functioning of the computing device <NUM>. The electronic components <NUM> are connected to the substrate assembly using connectors, such as board-to-board (BTB), zero insertion force (ZIF) connectors, universal spring contacts, pogo pin contacts, dome switch assemblies, SIM and SD card readers, and so on.

In the first stage of assembly <NUM>, the computing device <NUM> is shown with a face of the housing <NUM> removed and the device components <NUM> exposed via the removed face of the housing. In an embodiment covered by the claimed invention of device component exposure protection, low-modulus elastomers (LME) and thermoplastics (TP) are applied as precursor compositions to the device components <NUM> of the computing device <NUM>, such as a PCB substrate, electronic components associated with the PCB, connectors between components and the PCB, and so forth. Different LME-TP combinations impart different properties, and therefore enable better protection of specific components depending on the location and function of the device components <NUM>, or better protection of the different portions of the substrate assembly <NUM> themselves.

LME and TP are used to fill the void spaces within the housing <NUM> of the computing device <NUM> and encapsulate internal assemblies of the device components <NUM>, the electronic components <NUM>, connectors between the electronic components <NUM> and the substrate assembly, and so forth. With the void spaces within the housing filled with LME and TP, the device components <NUM> of the computing device <NUM> are protected from water and other materials to which the computing device may be exposed. Further, the LME and TP absorbs mechanical energy from shocks experienced when the electronic device is dropped or contacted, further protecting the electronic device and its components.

LME and TP are bound to the surface of the electronic components <NUM> attached to the substrate assembly <NUM>, such as by mechanical interlocking and/or reacting LME and TP precursors with coupling agents. The coupling agents form a bond between the LME and TP and the electronic components <NUM>. For example, consider the second stage of assembly <NUM>, in which one or more TP films <NUM> are applied to the device components <NUM>. The TP films <NUM> may be applied in a variety of ways, and using a variety of formulations.

TP are a class of copolymers or a physical mix of polymers (e.g., a plastic and a rubber), consisting of materials having both thermoplastic and elastomeric properties. While most elastomers are thermosets, thermoplastics flow at an elevated temperature and show characteristics typical of both rubbery materials and plastic materials. TP have the ability to stretch to moderate elongations and return to near original shape, allowing electrical (and non-electrical) interconnects to be disconnected and reconnected without damage to the TP. The ability of TP to stretch and return to its near original shape is enabled by crystals formed between chains, which effectively become cross-links in the structure of the TP. TP are formed with thermo-reversible bonds, while elastomers are formed with permanent covalent bonds.

For example, consider <FIG>, which illustrates examples of material structures that may be used to implement techniques of device component exposure protection. A thermoplastic structure <NUM> is shown, having a number of thermo-reversible bonds <NUM> forming crystals between chains <NUM> of the TP. The thermo-reversible bonds <NUM> cross-link the chains <NUM>, allowing the TP structure <NUM> to be stretched between the thermo-reversible bonds and return to nearly the original shape of the TP structure.

As discussed above, different TP formulations may be used for different applications from one device to another, or for various components within the same computing device. Based on materials of the components, the TP are implemented to adhere to manufacturing time constraints, space constraints within the computing device, likelihood of a component being moved during assembly or device rework, and so forth. Therefore, different TP formulations may be considered using criterion such as softening temperature to elevate the minimum rework temperature; application or bonding temperature, to elevate material solidification conditions and heat dissipation requirements during processing; working time to evaluate assembly requirements; <NUM>° peel strength, to elevate substrate adhesion strength; elastic modulus at room temperature, to elevate strength of the TP; and so forth.

In but one example, performance criterion for selection of a particular TP formulation can include a maximum rework temperature of <NUM>; TP not being brittle, as brittleness can cause failure during use of the computing device and life cycle testing including device drops; re-tension force of the TP unable to break the electrical connectors in the computing device when the connector is decoupled; and the TP does not break when it is reshaped around electrical connectors. Two TP films meeting these criteria are shown in Table <NUM> below:.

TP films may be applied to electrical and non-electronic components of a device in a variety of ways. For example, consider <FIG>, which illustrates example methods <NUM>(a) and <NUM>(b) of applying TP film to different connector types in implementations of device component exposure protection. A first method <NUM>(a) relates to TP film application with board-to-board (B2B) connectors. First, a TP film is applied over a socket end of a B2B connector and applied to surrounding solder joints (block <NUM>). The TP film is applied with a TP film tight-release liner in place and a TP film easy-release liner removed. To apply, the TP film is pressed to a substrate (e.g., the substrate assembly <NUM> of <FIG>) to initialize a bond between the TP film and the B2B connector. The tight-release liner is then removed, and the TP film is conformed around the socket. The TP film may be applied at room temperature.

Solder connections are covered by applying the TP film around a header end of the B2B connector (block <NUM>). The TP film is not applied directly to contacts on the header end of the B2B connector. The header and the socket ends of the B2B connector are then heated (block <NUM>), such as to a temperature around <NUM>, although the heat temperature may vary based on different TP films used and the material to which the TP film is applied. Heating the header and the socket ends of the B2B connector thus heats the TP film applied to each. The header end of the B2B connector is connected to the socket while the socket remains hot (block <NUM>). Once connected, the B2B connector and the socket form a B2B assembly, which is then cooled (block <NUM>) for further device assembly or device use.

The B2B assembly can be decoupled after completion of the process <NUM>(a), such as in device rework or repair. In one example, the B2B assembly is heated to ≤ <NUM> to unlock the thermo-plastic bonds of the TP film, although different formulations of TP film may require heating to different temperatures for decoupling. The B2B connector is disconnected from the socket while warm to prevent damage to the connector.

The second method <NUM>(b) relates to TP film application with zero insertion force (ZIF) connectors. First, a ZIF connector is mated with a flexible flat cable (block <NUM>). A TP film is applied to the mated ZIF connector and surrounding substrate (e.g., the substrate assembly <NUM> of <FIG>) (block <NUM>). The TP film may be applied to the mated ZIF connector at around <NUM> to initialize adhesion between the substrate and the TP film, although the heat temperature may vary based on different TP films used and the material to which the TP film is applied. A release liner is removed from the TP film, and the TP film is conformed tightly around the ZIF connector (block <NUM>). The mated ZIF connector and TP film are heated (block <NUM>) to form a seal around the ZIF connector. The mated ZIF connector and TP film may be heated to around <NUM> for <NUM>-<NUM> seconds, although the heat temperature and application time may vary based on different TP films used and the material to which the TP film is applied.

The ZIF connector may be decoupled at room temperature in this example without reheating using the TP-E and TP-F ("Product IDs") shown in Table <NUM>. However, the TP-E and TP-F films may need to be applied with each mating of the ZIF connector to the substrate.

Returning to a discussion of <FIG>, application of the TP film <NUM> to the device components <NUM> may be executed during device assembly without further operations to device component exposure protection. However, in the embodiment covered by the claimed invention, LME is applied to the device components <NUM> in addition to application of the TP film <NUM> to provide device component exposure protection. Consider the third stage of assembly <NUM>, where LME <NUM> has been applied to the device components <NUM> within the housing <NUM>.

In this embodiment covered by the claimed invention, the LME <NUM> is applied to various ones of the device components <NUM> by filling void spaces in the device housing <NUM> with a liquid precursor formulation of LME. Then, the liquid precursor of the LME <NUM> is cross-linked or cured using heat and/or exposure to ultraviolet (UV) radiation to encapsulate the device components <NUM> attached to the substrate assembly <NUM>. In the third stage of assembly <NUM>, the device housing <NUM> has been partially filled with the LME <NUM> precursor, as represented by several device components <NUM> which are large enough to not yet be entirely submerged by the liquid LME precursor. However, the several device components <NUM> remain covered by the TP film <NUM> as described above as the LME <NUM> precursor is applied.

In one or more implementations of device component exposure protection, the LME <NUM> is formed of polymeric chains (e.g., acrylate, acrylate ester, urethane acrylate oligomer, synthetic resin, silicone, and so forth) that are cross-linked by one or more techniques such as UV, thermal, or chemical curing, to name a few examples. Polymeric chains refer to a large molecule, or macromolecule, composed of many repeated subunits (monomers). The LME <NUM> may be comprised of hydrophobic groups and/or lipophilic groups, for instance, to increase water resistance or waterproofing around one or more of the device components <NUM>. Hydrophobic and/or lipophilic materials can be tailored to achieve different properties within the same device or different devices, such as to increase waterproofing for device components that may be more likely to be exposed to water. In cases where the LME and TP include more than one type of hydrophobic and/or lipophilic group, the different polymers can be derived from the same monomer or from different monomers.

The LME <NUM> may be formed with a lubricious component, and/or may be formed from liquid precursors. When the LME <NUM> is formed with liquid precursors, the liquid precursors may be cross-linked by exposure to UV radiation and/or heating to ≤ <NUM> for approximately <NUM> minutes, although the heat temperature and application time may vary based on different LME precursors used and the material to which the LME precursors are applied.

In one example, the LME <NUM> includes resins, a photo-initiator, and a thermal initiator which cross-link the LME upon exposure to UV radiation and/or heat ≤ <NUM>. In this example, the LME <NUM> may be comprised of <NUM> - <NUM>-wt% synthetic resins, <NUM> - <NUM>-wt% acrylic esters, <NUM> - <NUM>-wt% low-molecular weight resin, less than <NUM>-wt% thermal initiator, and less than <NUM>-wt% photo-initiators.

The mechanical and transport properties of the LME depend on a number of factors, including, for example, the density of side chains attached to the LME polymer backbone, the length/size of the LME chains between the elastomer junctions, the elastomer junction functionality, the density of elastomer junctions, and the chemical nature of the elastomer chains (hydrophobic, lipophilic, or both). LME mechanical properties are controlled by formulation and resultant network structure where φ is the number of chains attached to a junction; (µJ / Vo) is the junction density; and v is the number of chains between junctions. The phrase "junction functionality" refers to the number of polymer chains emanating from a cross-link of a network. The LME network parameters are related to the cycle rank of a network (ξ) as follows: ξ = v (φ-<NUM>)]/φ = µJ (φ-<NUM>)/<NUM>. For example, again consider <FIG>, which illustrates an LME structure <NUM>, having a number of elastomer junctions <NUM> between chains <NUM> of the LME. The elastomer junctions <NUM> cross-link the chains <NUM> when heat and/or UV radiation is applied to the LME structure <NUM>.

Returning to the discussion of <FIG>, the LME <NUM> may be formed with a lubricious (e.g., diluent) component or mixture of components, which may or may not be covalently incorporated into the LME. The lubricious component may be utilized to optimize the cross-link density of the LME <NUM> and the movement of polymer chains and network junctions in response to an applied stress, and to tailor the peel strength of the LME to a specific substrate, to name a few examples. Mechanically, adding a lubricious component to the LME impacts the extension ratio (direction <NUM>) to λ<NUM> = α (V/Vo)⅓ where α is the ratio of LME volumes without and with the lubricious component. In a similar fashion, directions <NUM> and <NUM> are mutually perpendicular and perpendicular to direction <NUM>, as represented by λ<NUM> = λ<NUM> = α-<NUM>/<NUM> (V/Vo)⅓.

In the third stage of assembly <NUM>, the LME <NUM> first wets the surface of one or more interfaces between the electronic components <NUM> and the substrate assembly <NUM>. A lubricious component in the LME <NUM> can be tailored to optimize surface wet ability. The LME <NUM> then bonds to the materials of the electronic components <NUM> and the substrate assembly <NUM> by covalent bonding, acid-base interaction, and/or mechanical interlocking. Mechanical interlocking refers to liquid precursors of the LME <NUM> that flow into pores in adhered surfaces of the electronic components <NUM> and/or the substrate assembly <NUM>, or around projections on the adhered surfaces.

Table <NUM> below indicates the mechanical characteristics of LME prepared from an optically clear, liquid precursor by cross-linking with UV-radiation, and the same LME formulated with lubricious components, measured by double lap-shear testing at room temperature with a strain rate of <NUM>-mm/min.

The diluent "a" refers to diphenyl-dimethylsiloxane copolymer, and the diluent "b" refers to butyl-terminated polydimethylisoxane. In general the LME in Table <NUM> have low-modulus and glass transition ("Tg") below -<NUM>. The phrase "glass transition" refers to the temperature where a reversible transition occurs in amorphous materials (or within amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a rubber-like state, as the temperature is increased. Lubricious components used in LME are, but not limited to, the diphenyl-dimethylsiloxane copolymer and butyl-terminated polydimethylsiloxane shown in Table <NUM>. Low deformation rate shear moduli typically decrease in LME formulations containing increasing amounts of additives, or diluents, because they have lower cross-link densities compared with LME without additives. In the acrylic-based LME (A in Table <NUM>), interactions between the diluent and the elastic component of the LME are observed and present evidence that methodologies to tailor the Tg and peel strength of a LME by choice of lubricious component may achieve desired properties based on specific application requirements.

Thermally activated and/or UV activated free-radical initiators may be added to an LME precursor formulation to affect cross-linking by heating the LME at temperatures to ≤ <NUM>, and/or exposure to UV radiation, respectively. Examples of thermally activated free-radical initiators include, but are not limited to, azobisisobutyronitrile (AIBN), acetyl peroxide, benzoyl peroxide, dicumyl peroxide, and lauryl peroxide. For example, consider <FIG>, which illustrates an example representation <NUM> of reaction time as a function of initiator concentration and reaction temperature. A thermally activated free-radical initiator may be incorporated into an LME liquid precursor formulation at initiator concentrations of approximately <NUM> moles/kg LME precursor to <NUM> moles/kg LME precursor. The representation <NUM> plots LME cross-linking reaction time <NUM> as a function of initiator concentration [I] <NUM> and reaction temperature <NUM> for AIBN. Although AIBN is used as an example in <FIG>, it is understood that one or a combination of multiple thermally activated free-radical initiators may be incorporated into LME liquid precursor formulations for different device and component scenarios.

Returning to the discussion of <FIG>, the LME <NUM> is shown as being applied in the third stage of assembly <NUM> when the device housing <NUM> is in a horizontal orientation, such as with a display of the device housing face-down. In the third stage of assembly <NUM>, the back of the device housing <NUM> has not yet been assembled with the rest of the device housing, leaving an open face of the device to apply the LME <NUM> liquid precursor. Turning to a fourth stage of assembly <NUM>, the device housing <NUM> has been flipped around (indicated by the arrow <NUM>) and such that the display of the device <NUM> is visible. The fourth stage of assembly <NUM> occurs after the TP and LME components have been applied to the device components <NUM> and any necessary solidification of the TP and LME components has taken place. The fourth stage of assembly <NUM> may include addition of any remaining portions of the device housing <NUM> to the computing device <NUM>, such as assembly of the back portion of the device housing.

Although the LME <NUM> is shown as being applied with the computing device <NUM> in a horizontal position and the device display facing down, the LME <NUM> may be applied with the device in any suitable orientation (e.g., horizontal, vertical, or any angle in between). Additionally, the LME <NUM> may be applied via different portions of the device housing <NUM>, such as through one or more ports that connect internal portions of the computing device <NUM> with the external environment, such as after assembly of the computing device is complete.

Alternatively, or additionally, the LME <NUM> may be applied to the electronic components <NUM> attached to the substrate assembly <NUM> at the component level. For instance, the LME <NUM> may be applied to a specific area of the substrate assembly <NUM>, or a region of an unassembled device, and cross-linked by applying UV radiation and/or heating to ≤ <NUM> for a time required to cross-link the LME, to name a few examples. The electronic components <NUM> may be assembled into a completed device subsequent to LME treatment.

In another example, the LME <NUM> may be applied to the electronic components <NUM> attached to the substrate assembly <NUM> at the device level. In this case, the LME <NUM> is injected into an assembled device through one or more ports, such as a SIM tray or another port designed for injection. As discussed above, the LME is then cross-linked by applying UV radiation and/or heating to ≤ <NUM> for a time required to cross-link the LME, to name a few examples. In yet another example, the LME <NUM> may be applied to a subset of the electronic components <NUM> at the component level, followed by assembly of the device and application of additional LME to the device components <NUM> at the device level.

In some cases, different areas of the substrate assembly <NUM> are encapsulated with different LME and/or TP to enable specific functionality of the computing device <NUM>, or to cover areas of closely-spaced electronic components <NUM> while leaving other areas of the substrate assembly <NUM> without any application of LME and/or TP. Leaving areas of the substrate assembly <NUM>, such as connectors, without application of LME and/or TP allows electronic components <NUM> located at these areas of the substrate assembly to be reconfigured or repaired without additional heating or curing steps, for example.

As discussed above, different combinations of LME and/or TP may be used to achieve different functionalities within a single electronic device. For example, a first electronic component is treated with a first LME and/or TP, and a second electronic component is treated with a second LME and/or TP, which has different mechanical, electrical, thermal, or chemical properties than the first LME/TP. The first LME/TP may provide a relatively complaint and/or a reversible adhesion promoting layer, while the second LME/TP provides targeted electrical, thermal, and/or chemical protection.

In another example, the substrate assembly <NUM>, such as a PCB, has an attached electrical connector that includes a housing and a plurality of leads attached to bonding pads formed on the PCB. The electrical connector may be positioned off of and attached to the PCB and an exterior surface of the housing of the electrical connector is spaced apart the leads attached to the PCB. A first LME and/or TP, which is compliant and enables multiple attachments, is applied directly to the electrical connector. A second LME and/or TP extends between the exterior surfaces of the housing to the PCB and covers the plurality of leads attached to the plurality of bonding pads.

<FIG> illustrates an example method <NUM> of device component exposure protection. The order in which the method is described is not intended to be construed as a limitation, and any number or combination of the described method operations can be performed in any order to perform a method, or an alternate method.

At <NUM>, device components are assembled within a housing of a computing device. The device components <NUM> include a substrate assembly <NUM>, such as a PCB, and electronic components <NUM>. The device components <NUM> may also include non-electronic components to be included for functioning of the computing device <NUM>. One or more portions of the device housing <NUM> may be left unassembled to allow an opening for application a protective material to the device components <NUM>.

At <NUM>, void spaces are filled around the device components with a protective material that prevents exposure of the device components to external matter that enters the housing. The protective material is the TP film <NUM>, which covers the substrate assembly <NUM> and the electronic components <NUM>. In addition, the protective material further comprises the LME <NUM>, which covers one or a combination of the substrate assembly <NUM> and/or the electronic components <NUM>.

To do so, the device housing <NUM> may be orientated with the device components <NUM> already assembled in order to facilitate filling the void spaces around the device components in the housing. For instance, the LME <NUM> may be applied via an opening in the device housing <NUM> as a liquid precursor while the device housing is in a horizontal position to fill the void spaces around the device components <NUM>, followed by application of heat ≤ <NUM> and/or UV radiation to cure the LME. Different combinations of TP and/or LME may be used within a single computing device <NUM> depending on which device components <NUM> are included in the computing device <NUM>, whether the computing device will need rework during assembly, how different components of the device may need to be repaired subsequent to delivering the device to market, which of the device components need more or less shock protection, and so forth.

At <NUM>, the device components and the protective material are enclosed within the housing of the computing device. For instance, the one or more portions of the device housing <NUM> that were left unassembled to allow the opening for application of the protective material are now added to the device housing to complete assembly of the computing device <NUM>.

At <NUM>, device components of a computing device are assembled within an enclosed housing that encloses the device components. The device components <NUM> include a substrate assembly <NUM>, such as a PCB, and electronic components <NUM>. The device components <NUM> may also include non-electronic components to be included for functioning of the computing device <NUM>. In this example, the device housing <NUM> may be fully assembled to enclose the device components <NUM>.

At <NUM>, void spaces are filled around the device components in the enclosed housing with a protective material that prevents exposure of the device components to external matter that enters the enclosed housing. The protective material is the LME <NUM>, which covers the substrate assembly <NUM> and the electronic components <NUM>. The LME <NUM> is applied via an opening in the assembled device housing <NUM> as a liquid precursor via a port or opening in the device housing to fill the void spaces around the device components <NUM>, followed by application of heat ≤ <NUM> and/or UV radiation to cure the LME. The opening may be a SIM tray or another port designed for injection, to name a few examples. Different combinations LME may be used within a single computing device <NUM> depending on which device components <NUM> are included in the computing device <NUM>, whether the computing device will need rework during assembly, how different components of the device may need to be repaired subsequent to delivering the device to market, which of the device components need more or less shock protection, and so forth.

The features of device component exposure protection described herein render devices, such as mobile devices, mechanically robust and waterproof. For example, electronic components and connectors included in conventional devices are typically vulnerable to moisture damage or ingress, which can cause electrical shorts and dendrite growth between circuit elements maintained at different electrical potential. However, device components treated with the techniques described herein, such as PCB boards with LME and/or TP protected ZIF connectors, measured no leakage current up to <NUM> VDC bias and did not exhibit corrosion current when covered with water. Corrosion current, for instance, can be measured by various techniques, such as using a Hewlett Packard 34401A Multimeter placed in series in the circuit to measure current.

Additionally, device components treated using LME, and LME with TP, were tested using procedures specified by IEC standard <NUM> water tests. Under these conditions, devices containing components treated with LME were tested in the off-state and the on-state for times ranging from <NUM> minutes to <NUM> hours immersed in around <NUM> meters of water. Following the tests, the devices containing components treated with LME operated per device specifications and displayed corrosion resistance by performing for <NUM> hours in the on-state. Further, the devices containing components treated with LME operated per device specifications and displayed corrosion resistance after being tested in the off-state for <NUM> minutes in around <NUM> meters of water.

In another example, devices containing components treated with LME were dropped in pool water containing chlorine to a depth of <NUM> meters to simulate, for instance, a user dropping the device into the pool as a result of a jarring collision, and the user dropping the device repeatedly into the pool. In both cases, the devices containing components treated with LME operated per device specifications after being retrieved. Additionally, the devices containing components treated with LME were able to perform video recordings while under water.

<FIG> illustrates various components of an example device <NUM>, which can implement examples of device component exposure protection. The example device <NUM> can be implemented in any form of an electronic and/or computing device, such as a mobile device. For example, the computing device <NUM> shown and described with reference to <FIG> may be implemented as the example device <NUM>.

The device <NUM> includes communication transceivers <NUM> that enable wired and/or wireless communication of device data <NUM> with other devices. The device data <NUM> can include device information and settings, such as information regarding how the device <NUM> and its components have been treated to have waterproof and/or water-resistant properties using the techniques described herein. The device data <NUM> can also include suggested techniques and information on how to treat the device <NUM> during repair, such as which portions of the device have been treated with LME and TP, how to reheat the LME and TP to return the protective material to a liquid state, and so forth. Additionally, the device data <NUM> can include any type of audio, video, and/or image data. Example transceivers include wireless personal area network (WPAN) radios compliant with various IEEE <NUM> (Bluetooth™) standards, wireless local area network (WLAN) radios compliant with any of the various IEEE <NUM> (WiFi™) standards, wireless wide area network (WWAN) radios for cellular phone communication, wireless metropolitan area network (WMAN) radios compliant with various IEEE <NUM> (WiMAX™) standards, and wired local area network (LAN) Ethernet transceivers for network data communication.

The device <NUM> may also include one or more data input ports <NUM> via which any type of data, media content, and/or inputs can be received, such as user-selectable inputs to the device, messages, music, television content, and any other type of audio, video, and/or image data received from any content and/or data source. The data input ports may include USB ports, coaxial cable ports, and other serial or parallel connectors (including internal connectors) for flash memory, DVDs, CDs, and the like. These data input ports may be used to couple the device to any type of components, peripherals, or accessories such as microphones and/or cameras. The data input ports may also be used in one or more implementations to transfer protective materials such as LME and/or TP to the interior of the device <NUM>, as described above.

The device <NUM> includes a processing system <NUM> of one or more processors (e.g., any of microprocessors, controllers, and the like) and/or a processor and memory system implemented as a system-on-chip (SoC) that processes computer-executable instructions. The processor system may be implemented at least partially in hardware, which can include components of an integrated circuit or on-chip system, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), and other implementations in silicon and/or other hardware. Alternatively or in addition, the device can be implemented with any one or combination of software, hardware, firmware, or fixed logic circuitry that is implemented in connection with processing and control circuits, which are generally identified at <NUM>. The device <NUM> may further include any type of a system bus or other data and command transfer system that couples the various components within the device. A system bus can include any one or combination of different bus structures and architectures, as well as control and data lines.

The device <NUM> also includes computer-readable storage memory <NUM> that enables data storage, such as data storage devices that can be accessed by a computing device, and that provide persistent storage of data and executable instructions (e.g., software applications, programs, algorithms, functions, and the like). Examples of the computer-readable storage memory <NUM> include volatile memory and non-volatile memory, fixed and removable media devices, and any suitable memory device or electronic data storage that maintains data for computing device access. The computer-readable storage memory can include various implementations of random access memory (RAM), read-only memory (ROM), flash memory, and other types of storage memory devices in various memory device configurations. The device <NUM> may also include a mass storage media device.

The computer-readable storage memory <NUM> provides data storage mechanisms to store the device data <NUM>, other types of information and/or data, and various device applications <NUM> (e.g., software applications). For example, an operating system <NUM> can be maintained as software instructions with a memory device and executed by the processor system <NUM>. The device applications may also include a device manager, such as any form of a control application, software application, signal-processing and control module, code that is native to a particular device, a hardware abstraction layer for a particular device, and so on.

The device <NUM> also includes an audio and/or video processing system <NUM> that generates audio data for an audio system <NUM> and/or generates display data for a display system <NUM>. The audio system and/or the display system may include any devices that process, display, and/or otherwise render audio, video, display, and/or image data. Display data and audio signals can be communicated to an audio component and/or to a display component via an RF (radio frequency) link, S-video link, HDMI (high-definition multimedia interface), composite video link, component video link, DVI (digital video interface), analog audio connection, or other similar communication link, such as media data port <NUM>. In implementations, the audio system and/or the display system are integrated components of the example device. Alternatively, the audio system and/or the display system are external, peripheral components to the example device.

The device <NUM> can also include one or more power sources <NUM>, such as when the device is implemented as a mobile device or portable camera device. The power sources may include a charging and/or power system, and can be implemented as a flexible strip battery, a rechargeable battery, a charged super-capacitor, and/or any other type of active or passive power source.

Claim 1:
A computing device (<NUM>), comprising:
device components (<NUM>) including a substrate assembly (<NUM>) with electronic components (<NUM>, <NUM>) attached to the substrate assembly (<NUM>), the components and the substrate assembly (<NUM>), being enclosed within a housing (<NUM>) of the computing device;
a thermoplastic film (<NUM>) applied to and covering the electronic components (<NUM>, <NUM>) and the substrate assembly (<NUM>), and
a low modulus elastomer protective material (<NUM>) contained within the housing (<NUM>), overlying the thermoplastic film, and filling void spaces around the device components (<NUM>), the thermoplastic film and the low modulus elastomer protective material preventing exposure of the device components (<NUM>) to external matter that enters the housing (<NUM>).