This can relate to dome switches and, more particularly, to systems and methods for preventing liquids from contacting circuit elements of dome switches.
Dome switches are common to various electronic devices (e.g., portable media players and cellular telephones). A dome switch generally includes a dome having a conductive inner surface operative to close a circuit when the dome is deformed and the conductive inner surface is brought into contact with a conductive contact pad positioned under the dome. The conductive contact pad is usually provided on a circuit board of the electronic device, such that when the dome is physically deformed by a user, the circuit of the switch can provide electrical signals to other components of the electronic device.
If a user mistakenly pours liquid on the electronic device, the liquid can sometimes come into contact with the circuit elements of the dome switch (e.g., the conductive inner surface of the dome and/or the conductive contact pad). Water or any other foreign liquid coming into contact with one or more of the circuit elements may short the circuit of the dome switch.
Systems and methods for preventing liquids from contacting circuit elements of a dome switch are provided.
In some embodiments, a dome switch may include a conductive contact pad coupled to a mounting surface and a dome coupled to the surface and positioned over the conductive contact pad. The dome may include a conductive dome region on an inner surface of the dome. The dome switch may also include at least one sheath extending between the conductive contact pad and the conductive dome region for preventing liquid external to the at least one sheath from contacting the conductive dome region and the conductive contact pad. The sheath may be deformable or rigid.
In some embodiments, a method for preventing liquid from harming a dome switch may include positioning a first sheath around the periphery of a conductive inner surface region of a dome of the switch. The method may also include positioning a second sheath around the periphery of a conductive contact pad of the switch. An open end of the second sheath may extend through an open end of the first towards the conductive inner surface region.
The above and other features of the invention, its nature, and various advantages will be more apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings in which:
Systems and methods for preventing liquids from contacting circuit elements of a dome switch are provided and described with reference to
A dome switch may include a deformable dome having a conductive dome region on an inner surface of the dome. The deformable dome may be positioned over a conductive contact pad. The conductive contact pad may be, for example, a contact pad on a mounting surface (e.g., a surface of a circuit board). A first end of a first sheath may be coupled to the inner surface of the dome around at least a portion of the dome's conductive dome region, and the second end of the sheath may extend away from the dome towards the conductive contact pad. A first end of a second sheath may be coupled to the mounting surface around at least a portion of the periphery of the conductive contact pad, and the second end of the sheath may extend away from the contact pad towards the dome.
When a user presses an outer surface of the dome, the dome may deform such that the conductive dome region of the inner surface of the dome may contact the conductive contact pad positioned under the dome, thus, closing a circuit. When the dome deforms, the second end of the second sheath may extend into the first sheath and the two sheaths may interlock and prevent liquid from contacting the conductive dome region or the conductive contact pad.
Dome 12 may be made from any suitable deformable material, such that, when a user presses outer surface 13 in substantially the direction of arrow D towards surface 17, dome 12 may deform in such a way that conductive contact region 14 may contact conductive contact pad 16. When conductive contact region 14 contacts conductive contact pad 16, an electrically conductive path may be created therebetween, thereby switching a circuit that can be detected by electronic device 1. For example, dome 12 may be made from rubber or silicone. In some embodiments, dome 12 or at least inner surface 11 may be made from a conductive material, such as metal (e.g., aluminum or steel). In such embodiments, inner surface 11 itself may be conductive contact region 14.
Dome 12 may have any suitable shape. For example, dome 12 may have a semi-spherical or polygonal shape. In some embodiments, the shape of dome 12 may be determined or selected based on restrictions or limitations of device 1, circuit board 15, conductive contact region 14, and/or conductive contact pad 16. The shape of outer surface 13 may be determined or selected based on a predetermined force or range of forces that may be applied to dome 12 in direction D by an average user such that dome 12 may deform while remaining within a predetermined foot print on surface 17.
Dome 12 may be coupled to mounting surface 17 (e.g., a surface of circuit board 15) using any suitable approach such that, when a user deforms dome 12, conductive contact region 14 of inner surface 11 may contact conductive contact pad 16. For example, dome 12 may be coupled to mounting surface 17 using an adhesive or tape (e.g., see adhesive 19 of
Dome 12 may be sized using any suitable approach. For example, dome 12 may be sized based on the size of electronic device 1 or based on the size of contact pad 16. Dome 12 may have any suitable mechanical properties such that, for example, the force needed to deform dome 12 for adequately bringing contact region 14 into contact with contact pad 16 is a force able to be easily imparted by a user of device 1. Dome 12 may be manufactured using any suitable approach. In some embodiments, if dome 12 is metal, it may be stamped or punched from a sheet of metal. In other embodiments, dome 12 may be manufactured using molding, machining, cutting, forming, or through any other suitable manufacturing process.
Dome switch 10 may also include a first sheath 18 and a second sheath 20 for preventing liquid from harming the circuit elements of the switch. First sheath 18 may have any suitable shape for surrounding the periphery of contact region 14 on inner surface 11 of dome 10 and for fitting over second sheath 20. For example, first sheath 18 may have a cylindrical or conical sheath portion 18c extending between a first open end 18a coupled to inner surface 11 about contact region 14 and a second open end 18b, and second sheath 20 may have a cylindrical or conical sheath portion 20c extending between a first open end 20a coupled to surface 17 and a second open end 20b. When a user applies pressure to external surface 13 of dome 12, at least a portion of second sheath 20 may extend into first sheath 18 through second end 18b. Second sheath 20 may have any suitable shape for surrounding the periphery of contact pad 16 and for fitting within first sheath 18. For example, the shape of first open end 20a of second sheath 20 may be determined or selected based on the size of contact pad 16b, such that open end 20a may be coupled to surface 17 around the periphery of contact pad 16b.
First sheath 18 may be constructed from any suitable material such that, when a user applies pressure on outer surface 13 of dome 12 in the direction of arrow D, first sheath 18 may slide down around second sheath 20 such that contact region 14 may contact conductive contact pad 16. For example, first sheath 18 may be constructed from rubber, silicone, or a hydrophobic mesh.
First sheath 18 may be coupled to inner surface 11 of dome 12 using any suitable approach such that open end 18a of first sheath 18 may be positioned around conductive region 14 to prevent liquid external to sheath 18 from coming into contact with conductive region 14. For example, open end 18a of first sheath 18 may be coupled to inner surface 11 using any suitable adhesive. In some embodiments, if first sheath 18 is made from rubber or any other suitable material, for example, sheath 18 may be coupled to inner surface 11 of dome 12 by heating open end 18a of first sheath 18 such that it may be heat-sealed against inner surface 11 about conductive region 14.
Second sheath 20 may be constructed from any suitable material such that, when a user applies pressure on outer surface 13 of dome 12, first sheath 18 may slide over second sheath 20 and may allow conductive region 14 of dome 12 to come into contact with contact pad 16 for example, second sheath 20 may be constructed from rubber, silicone, or a hydrophobic mesh.
First end 20a of second sheath 20 may be coupled to surface 17 using any suitable approach such that a portion of second sheath 20 may be positioned around the periphery of contact pad 16 to prevent liquid external to sheath 20 from coming into contact with contact pad 16. For example, second sheath 20 may be coupled to surface 17 using an adhesive. In some embodiments, at least open end 20a of sheath 20 may be made at least partially from rubber, or any other suitable material, for example, such that open end 20a of sheath 20 may be coupled to surface 17 by heating end 20a of second sheath 20 such that sheath 20 may be heat-sealed against surface 17 (e.g., about contact pad 16b).
First sheath and second sheath 20 may be manufactured using any suitable approach. In some embodiments, each sheath may be manufactured using molding, machining, cutting, forming, or any other suitable manufacturing process.
Conductive contact pad 16 may be coupled to any suitable portion of surface 17 or sheath 20 such that when conductive region 14 and contact pad 16 of switch 10 contact each other, a circuit of device 1 (e.g., a circuit of circuit board 15) may be switched. Contact pad 16 may be constructed from copper or any other suitable material. Conductive contact pad 16 (e.g., conductive contact pad 16b) may be coupled to surface 17 using any suitable coupling approach. For example, contact pad 16b may be coupled to surface 17 through soldering. Conductive contact pad 16 (e.g., pad 16a may be coupled to sheath 20 (e.g., near end 20)) using any suitable approach, such as with an adhesive. Conductive contact pad 16 may be sized using any suitable approach. For example, contact pad 16 may be sized based on the sizes of first sheath 18 and second sheath 20. Conductive contact pad 16 may be manufactured using any suitable approach. In some embodiments, contact pad 16 may be manufactured using machining and/or cutting. In some embodiments, contact pad 16 may be manufactured with circuit board 15 of device 1. In some embodiments, pad 16 may be physically coupled to mounting surface 17 that is not part of circuit board 15, but pad 16 may be electrically coupled to circuit board 15 using any suitable approach (e.g., using wire 21).
In some embodiments, first sheath 18 and/or second sheath 20 may be substantially rigid and may not deform when dome 12 deforms in response to a user's force. In such embodiments, as shown in
However, in other embodiments, switch 10 may not include raised contact pad 16a and for example, as shown in
When user 5 pushes down on outer surface 33 in the direction of arrow D, dome 32 may deform such that contact region 34 may contact conductive contact pad 36 as shown in
In operation, when user 15 pushes down on outer surface 53 in the direction of arrow D, dome 52 may deform such that conductive contact region 54 can contact conductive contact pad 56, as shown in
Spring 79 may be constructed from any suitable material such that when user 5 applies pressure to outer surface 73 of dome 72 in direction of arrow D, spring 79 along with sheath 78 may compress, allowing contact region 74 of dome 72 to contact conductive contact pad 76. For example, spring 79 may be constructed from high-carbon alloys, chrome silicone, chrome vanadium, or stainless steel.
Spring 79 may be manufactured using any suitable approach. In some embodiments, spring 79 may be manufactured using machining, cold and/or hot winding, cutting, forming, or any other suitable manufacturing process. Inner and outer sheaths 78d and 78e along with spring 79 embedded therebetween may be operative to compress, bringing the coils of spring 79 closer together when user 5 applies force to outer surface 73 in direction of arrow D and then returning to its original state when the force is removed by having the coils of spring 79 move apart. In some embodiments, dome 72 may not have to return to its undeformed state on its own after user 5 stops applying a force to dome 72 in direction D. Instead, dome 72 may be returned to its undeformed state by coils of spring 79 moving apart and increasing the height of sheath 78, thereby moving portions of dome 72 upward in the direction of arrow U.
In operation, when user 5 pushes down on outer surface 73 in the direction of arrow D, dome 72 may deform such that contact region 74 comes into contact with contact pad 76, as shown in
The above described embodiments of the invention are presented for purposes of illustration and not of limitation.