1. Field of the Invention
The described embodiments relate generally to portable computing devices. More particularly, the present embodiments relate to providing protection against moisture intrusion.
2. Description of the Related Art
In recent years, small form factor consumer electronic products such as media players and cellular phones have become smaller, lighter and yet more capable by incorporating more powerful operating components into smaller and more densely packed configurations. This reduction in size and increase in density can be attributed in part to the manufacturer's ability to fabricate various operational components such as processors and memory devices in ever smaller sizes while increasing their power and/or operating speed. However, this trend to smaller sizes and increase in component density and power, however, poses a number of continuing design and assembly challenges.
For example, small form factor consumer electronic products, such as a media player, can require the assembly of a number of components into an enclosure having an extremely small volume. Assembling the various components into the housing having such a small size can require complex, expensive, and time consuming assembly techniques. Moreover, aesthetic considerations can severely restrict the placement, size, and number of components used in the manufacture of the small form factor consumer electronic product. For example, proper alignment of external features such as buttons can be extremely difficult to accomplish when the small size of the consumer electronic device itself can severely reduce the available tolerance stack of the assembled components.
Yet another design challenge is insuring that the assembled components that are visible maintain their aesthetic look and “feel” over an expected operating lifetime and under anticipated environment operating conditions of the consumer electronic product. One component that can be visible on a consumer electronic product is a switch. Typically, a switch, such as an electromechanical switch, can be user actuated to provide operational inputs for controlling a device. For electromechanical switches, it is desirable that, over the expected lifetime of the device, 1) the switch maintains operable for its intended purpose, i.e., a proper input is generated according to the switch position, and 2) the “feel” of the switch is maintained, i.e., it moves smoothly from position to position in the manner for which it was designed and does not stick.
An environmental condition that can cause an electromechanical switch to deviate from its intended operational performance is moisture intrusion. Moisture intrusion can facilitate the build-up of oxides on metal components or the deposition of particulates within the switch that can affect the switch's electrical outputs and the feel of the switch during actuation. For small, high-density components with limited operational tolerances, preventing moisture intrusion can be difficult. Thus, in view of the foregoing, there is a need for improved techniques for inhibiting moisture flow and/or mitigating the effects of moisture intrusion in consumer electronic products.
Broadly speaking, the embodiments disclosed herein describe methods, apparatus and materials for forming components well suited for use in consumer electronic devices, such as laptops, cellphones, netbook computers, portable media players and tablet computers. In more detail, the embodiments relate to systems, methods, and apparatus for providing a moisture resistant environment for small form factor electronic devices. In a particular, the systems, methods and apparatus can be related to providing a moisture resistant environment that can be applied to the design of electromechanical switches. The electromechanical switches, described herein, can typically be located on an outer surface of the consumer electronic device and can be configured to provide an electrical output signal in response to an actuation of the switch via an applied mechanical force, such as in response to a mechanical force generated by a user.
For the electromechanical switch, a two pronged approach can be used to provide a moisture resistant environment. First, the switch can be sealed to limit moisture intrusion. Second, features can be included within the switch that help to mitigate the effects of any moisture that penetrates into the switch. Towards mitigating moisture effects, a distribution mechanism for a moisture inhibiting material, such as an oleophobic material, can be included within the electromechanical switch. In one embodiment, the distribution mechanism can be configured to continually reapply the moisture inhibiting material on sensitive components during operation of the switch.
An electromechanical switch can include conductive components, such as metal components, that allow circuits with differing electrical properties to be formed depending on a position of the electromechanical switch. Moisture intrusion within the switch can degrade switch performance over time as a result of water-based electrochemical deposition processes that can occur when conductive components are exposed to water. The water-based electrochemical deposition process can be mitigated by providing a moisture inhibiting coating on the conductive components, such as a coating of an oleophobic material. Friction between components within the electromechanical switch during repeated actuation of the switch can remove the moisture inhibiting material. The distribution mechanism for the moisture inhibiting material can be configured to reapply the moisture inhibiting material to one or more conductive surfaces within the switch so that during operation a moisture barrier is maintained and/or replenished on the one or more conductive surfaces where the moisture inhibiting material might be removed as a result of friction. Thus, a degradation of switch performance during its operational lifetime can be prevented.
In one embodiment, an electromechanical switch is provided. The electromechanical switch can include conductive components that are configured to change position relative to one another in response to a mechanical input where a change in position of the conductive components relative to one another affects electrical properties of a circuit including the conductive components. The electromechanical switch can further include a distribution mechanism for replenishing on surfaces within the switch a moisture inhibiting layer formed from a material, such as an oleophobic material. In particular, when the moisture inhibiting material is removed from the different surface portions as a result of at least friction between the conductive components during actuation of the electromechanical switch, the distribution mechanism can be configured to replenish the moisture inhibiting material in areas where it has been removed.
In a particular embodiment, a slider switch with a distribution mechanism for applying a moisture inhibiting material can be provided. The slider switch can include 1) a carrier body including an electrical bridging component attached to the carrier body and 2) a base including a number of electrical contact pads. When the base is mounted to a housing of an electronic device, the base and the carrier body can be configured to change positions relative one another, such as when a sliding force is applied to the carrier body.
In one embodiment, the electrical bridging component can be a conductive spring arm, such as a metal spring arm and the base can include three or more electrical contact pads, such as metal contact pads. The sliding force can cause the spring arm to make electrical contact with no more than two of the electrical contact pads at a time. Thus, in different positions of the electromechanical switch, the spring arm can be in contact with different ones of the electrical contact pads. When the carrier body moves relative to the base of the slide switch, the moisture inhibiting distribution mechanism can be configured to reapply a moisture inhibiting layer to portions of a surface of each of the contact pads. In particular, to prevent moisture intrusion and resulting electrochemical processes that can damage the switch, the moisture inhibiting layer can be replenished over portions of contact pads that are not in contact with the spring arm thereby providing a moisture barrier at all times.
Other aspects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
The invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:
Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims.
Apparatus, methods and systems are described for improving moisture resistance in electronic devices. Electrochemical processes associated with moisture intrusion can damage and thus, reduce the operational lifetime of electronic devices and otherwise prevent the electronic device from operating in accordance to its intended design. When moisture instruction occurs, water-based electrochemical processes can cause corrosion of metal components and a deposition of materials that can cause shorts in electronic circuitry. An electrochemical switch is one example of component included on an electronic device that can be susceptible to damage from moisture intrusion and its associated water-based electrochemical processes.
In more detail, an electromechanical switch can include conductive contact pads and a conductive bridging component for forming an electrical circuit involving two or more of the conductive contact pads. The electromechanical switch can be configured so that a position of the bridging component and the conductive pads are adjustable relative to one another. A positional change involving the components of the switch can proceed in response to application of mechanical force to the switch. By changing the position of the conductive component relative to the conductive pads, the conductive component can be brought into contact with different ones of the conductive pads to change the electrical properties associated with the switch. The electrical properties of the switch in different positions can be detected and can be used to determine a control signal related to operation of the electronic device including the switch.
As a result of repeated actuation of the switch, i.e., when the position of the bridging component and the conductive pads are changed relative to one another, the friction resulting from the bridging component and the conductive pads moving against one another can cause a loss of material from one or both of the conductive pads and the bridging component. As an example, for a bridging component with a contact surface that is narrower than the conductive pad, a rut about the width of the contact surface can form in the conductive pad as a result of repeated actuation of the switch. The depth of the rut can increase over time as more material is lost from the contact pad.
To prevent damage resulting from moisture intrusion into a component, such as a switch, a moisture barrier including seals can be provided that is intended to limit the moisture penetration into the component. The ability of the moisture barrier to prevent moisture penetration is related to the quality of the seals. For a component, such as an electronic switch with parts that move relative to one another, maintaining a moisture-proof seal while allowing the components to move easily relative to one another can be difficult.
In light of the difficultly of providing a moisture proof seal for a moveable component, measures can be taken to mitigate the effects of moisture intrusion. One approach mitigating the effects of moisture intrusion is to provide a moisture-inhibiting coating or barrier on the internal components, such as the bridging component and/or conductive pads used to form an electrical circuit in an electromechanical switch. As an example, during assembly, the bridging component and/or conductive pads can be coated with a viscous oleophobic material that is applied in a semi-solid form, such as a “grease.” The oleophobic material can prevent moisture from coming into contact with the interior components, such as the bridging component and the conductive pads, and thus, prevent damage on the surface of these components resulting from water-based electrochemical processes.
A difficulty with using a moisture inhibiting coating is that in areas where the bridging component and the contact pads come into contact, the moisture inhibiting coating can be removed as a result of friction. As described above, for a slider switch, friction can cause ruts to be formed in the contact pads where the bridging component and the contact pads slide against one another. In the ruts, where contact is needed to complete an electrical circuit, the moisture inhibiting material can be removed. After the moisture inhibiting coating is removed, water-based electrochemical processes can cause damage that degrades the performance of the switch. The damage can affect the aesthetic feel of the switch, such as by causing the switch to stick, and can possibly prevent the switch from generating proper output signals that are used to control the electronic device.
In the embodiments discussed herein, apparatus and methods are described that allow a moisture inhibiting coating to be maintained on internal surfaces of an electromechanical switch. In one embodiment, a distribution mechanism is described that allows a moisture inhibiting material that is removed as the result of friction between a bridging component and a contact pad to be reapplied to replenish the moisture inhibiting material on these surfaces. The distribution mechanism can be configured to reapply the moisture inhibiting material when the electromechanical switch is actuated as a result of a mechanical input. In one embodiment, the electromechanical switch can be a slider switch where the distribution mechanism reapplies the moisture inhibiting material when the slider switch is moved from position to position.
To illustrate the embodiments, the general operation of an electromechanical switch, such as a slider switch, is described with respect to
Button 101 can take many forms such as a two, three or more position button. For example, when configured as a two position switch, hold switch button 101 can have a first and second position. In order to provide the user with a quick and unambiguous indication of the position of hold switch button 101, colored labels can be used to provide distinctive visual indicia. For instance, the labels can include a green portion (GP on
Slide switch 101 can be configured to slide within switch carrier 102. Slide switch carrier 102 can be formed of any suitable resilient material such as plastic. The slide switch and the switch carrier can be formed from a suitable manufacturing method, such as an injection molding process.
In order to minimize the intrusion of moisture from the external environment through slide switch carrier 102, slide switch carrier seal 104 can be placed on slide switch carrier 102. Slide switch carrier seal 104 can be formed of moisture inhibiting material such as silicone rubber. In this way slide switch carrier seal 104 can have a shape that fits snuggly within slide switch carrier 102. The carrier seal 104 can limit but may not totally prevent moisture intrusion into the internal body of the switch assembly 100.
Internally, the slide switch assembly 100 can include a number of conductive components. The conductive components can form electronic circuits with different electrical properties depending on a position of the slide switch 101. The conductive components can be damaged as a result of moisture that penetrates past the carrier seal 104 and into the internal body of the switch assembly 100. Damage from the moisture intrusion can be prevented by coating the internal conductive components with a moisture inhibiting material, such as an oleophobic material. However, as described above, when the switch assembly 100 is repeatedly actuated, the moisture inhibiting material coating can be removed on portions of the conductive components that come into contact with one another as a result of friction between the components that occurs during actuation of the switch. In the areas where the coating has been removed, chemical processes associated with moisture intrusion can damage the conductive components and affect the operation of the switch 100. Apparatus and methods for preventing this damage are described in more detail with respect to
The slide switch assembly 100 is provided for the purposes of illustration only. In other embodiments, different types of slide switches with configurations different that what is shown in
During actuation of the switch, the carrier body 202 can shifted from a first position to a second position in response to an input force. For instance, the carrier body can be shifted to the left from the right where the carrier body 202 can move in such a way that bridging component 204 can establish an electrical connection between contact pad 206 and contact pad 208. The electrical connection can determine the control signal generated by the switch 200.
After the carrier body 202 is moved to the position shown in
When the carrier body 202 is moved in the opposite direction to a position where the bridging component 204 makes contact with contact pads 208 and 210, the contact pad 206 can be left bare. As a result of the bridging component 204 moving over the contact pad 206, a surface portion of the contact pad 206 can be removed. Again, the surface portion can include the moisture inhibiting material 212 coating the contact pad 206 as well as portion of the underlying conductive material used to form the contact pad 206.
In order to prevent corrosion due to the presence of moisture on a bare surface of contact pads 206 or 210, the moisture inhibiting layer 212 can be provided on top of the contact pads 206 and 210 such that it forms a moisture barrier. As described above with respect to
In particular embodiments, when the carrier body 202 and the base 215 are moved relative to one another, the moisture inhibiting layer can serve to lubricate the switch 200 and reduce friction between the bridging component 204 and the base 215, which includes the contact pads, such as 206, 208 and 210. The reduced friction can affect the aesthetic feel of the switch 200. The moisture inhibiting layer 212 can be formed of oleophobic material such as grease that can inhibit the intrusion of moisture from the external environment from reaching the surface of exposed contact pad 210. Thus, water-based based electrochemical processes, such as corrosion or deposition can be prevented from occurring on the exposed surfaces of the contact pads. As described above, these processes can damage the switch such that its electrical or mechanical properties are affected. For instance, the electrochemical processes can cause electrical shorts in the switch or can cause the switch to stick.
To assure a relatively even distribution of layer 212 over the contact pads, such as 206 and 210, applicators, such as 214 and 216 can be provided. In one embodiment, the applicators can take the form of wipers. In this embodiment, the applicators can be configured to “wipe” the material of layer 212 evenly across the contact pads. Thus, as the carrier body 202 is moved from position to position, friction between the bridging component 204 and the contact pads can cause material, such as the moisture inhibiting material 212 to be removed from the contact pads and the passing of the applicators over the contact pads can cause the moisture inhibiting material 212 to be replenished on the contact pads. In this way, the moisture inhibiting layer 212 can be maintained such that the surfaces of contact pads 206, 208, and 210 can be protected from moisture intrusion and any associated water-based processes that can damage the switch 200.
In
In one embodiment, reservoirs, such as 219a and 219b, can be located in the interior of the carrier body 202. During manufacture, the reservoirs can be filled with the moisture inhibiting material 212. The reservoirs can be coupled to each of the applicators 214 and 216 and can serve to replenish the applicators with moisture inhibiting material during operation of the switch.
An advantage of replenishing the moisture inhibiting material by pre-impregnating the applicators and/or supplying the applicators with additional material from reservoirs in the carrier body 202, as compared to the embodiment described above with respect to
In another embodiment, the reservoir 218 may not be used. Instead, the features 220 can include an internal bladder 220a for storing the moisture inhibiting material 212. An interface between the bladder 220a and an outer portion 220b of the feature 220 can control a rate at which the moisture inhibiting material is dispensed into the outer portion 220b. In one embodiment, the contact pads can be slightly raised or a raised surface can be provided on the base (not shown). The raised surface can be configured such that when the features 220 pass over the raised surfaced the internal bladder 220a is squeezed forcing the moisture inhibiting material into the outer portion 220b of the feature 220. The moisture inhibiting material can then be dispensed onto the contact pads.
In
In this embodiment, the applicators 214 and 216 can be formed from a compressible material. The applicators can be installed such that they are compressed when resting on the base 215 portion outside of the recesses. Then, as the applicators move over the recesses, the applicators can expand to maintain contact and follow along the surface of the recess.
Other input/output mechanisms can be arranged around a periphery of the housing 402. For instance, a power switch, such as 410 can be located on a top edge of the housing and a volume switch, such as 412, can be located along one edge of the housing. In addition, a multi-position slider switch 403 for generating control signals based upon a position of the switch can be located on a side opposite the volume switch 412. An audio jack 416 for connecting headphones or another audio device and a data/power connector interface 418 are located on the bottom edge of the housing. The housing 400 also includes an aperture for a camera 415 that allows video data to be received.
In different embodiments, the switches, such as the input button 414, the power switch 410, the volume switch 412 and the multi-position slider switch 403 can include a moisture inhibiting material distribution mechanism. The moisture inhibiting material distribution mechanism can be configured to replenish a moisture inhibiting material on internal surface components of the switch. The distribution mechanism can utilize a portion of the mechanical force that is input to actuate the switch to replenish the moisture inhibiting material on internal surfaces within the switch. For instance, for the input button 414, the distribution mechanism can utilize the downward force that is supplied to actuate the switch to replenish the moisture inhibiting material. Whereas, for the multi-position slider switch 403, the distribution mechanism can utilize the substantially parallel force that is supplied to actuate the switch 403 to replenish the moisture inhibiting material.
The media player 500 can store media data pertaining to media items in a file system 504 and a cache 506. The file system 504 can, typically, be a storage disk or a plurality of disks or a solid-state storage device, such as flash memory. The file system can provide high capacity storage capability for the media player 500. However, since the access time to the file system 504 can be relatively slow, the media player 500 also can include a cache 506. The cache 506 can be, for example, Random-Access Memory (RAM) provided by semiconductor memory. The relative access time to the cache 506 can be substantially shorter than for the file system 504. However, the cache 506 may not have the large storage capacity of the file system 504. Further, the file system 504, when active, can consume more power than does the cache 506. The power consumption can be particularly important when the media player 400 is a portable media player that is powered by a battery (not shown).
The media player 500 can also include a user input device 508 that allows a user of the media player 500 to interact with the media player 500. For example, the user input device 508 can take a variety of forms, such as a button, keypad, dial, etc. Still further, the media player 500 includes a display 510 (screen display) that can be controlled by the processor 502 to display information to the user. A data bus 511 can facilitate data transfer between at least the file system 504, the cache 506, the processor 502, and the CODEC 512.
In one embodiment, the media player 500 can store a plurality of media items (e.g., songs, video files and podcasts) in the file system 504. When a user desires to have the media player play a particular media item, a list of available media items is displayed on the display 510. Then, using the user input device 508, a user can select one of the available media items. The processor 502, upon receiving a selection of a particular media item, can supply the media data for the particular media item to a coder/decoder (CODEC) 512. The CODEC 512 can then produce analog output signals for a speaker 514. For a video based media item, a video CODEC can be utilized to output video images to the display 510. The speaker 514 can be a speaker internal to the media player 500 or external to the media player 500. For example, headphones or earphones that connect to the media player 500 would be considered an external speaker.
The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, DVDs, magnetic tape, flash memory and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.
Many features and advantages of the present invention are apparent from the written description and, thus, it is intended by the appended claims to cover all such features and advantages of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, the invention should not be limited to the exact construction and operation as illustrated and described. Hence, all suitable modifications and equivalents may be resorted to as falling within the scope of the invention.
This application claims priority under 35 U.S.C. §119(e) from co-pending U.S. Provisional Patent Application No. 61/381,034, filed Sep. 8, 2010, titled “WATER INHIBITING SLIDE SWITCH,” which is incorporated by reference and for all purposes.
Number | Date | Country | |
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61381034 | Sep 2010 | US |