Patent Application
20090318188
1. Field of the Invention
The invention relates to an electrical device and, more particularly, to grounding in an electrical device.
2. Brief Description of Prior Developments
Xenon flash devices have been used for cameras in the past. A xenon flash module can have a 320V capacitor/capacitors for example. This kind of module is covered under a new European Union (EU) safety standard. One safety issue relates to grounding of the capacitor used with the flash. Using an extra soldering pin for a grounding-type of solution for the capacitor is not possible because of current manufacturing processes of capacitors.
The following summary is merely intended to be exemplary. The summary is not intended to limit the scope of the claimed invention.
In accordance with one aspect of the invention, an apparatus is provided comprising circuitry; a camera connected to the circuitry; and a flash connected to the circuitry. The flash comprises a flash lamp and a capacitor. The capacitor comprises a cathode electrically connected to a housing of the capacitor by an electrically conductive closure. The closure closes an aperture through the housing. The cathode is connected to ground through a conductor of the circuitry.
In accordance with another aspect of the invention, an apparatus is provided including a housing; an anode extending into the housing; a cathode extending into the housing spaced from the anode; and a closure in an aperture of the housing. The closure includes electrically conductive material. The anode and cathode extend through the closure. The closure electrically connects the cathode to the housing.
In accordance with another aspect of the invention, an apparatus is provided comprising a housing; an anode extending into the housing; a cathode extending into the housing spaced from the anode; a closure in an aperture of the housing, wherein the closure comprises electrically conductive material, wherein the anode and cathode extend through the closure; and an electrical insulator between the anode and the closure, wherein the insulator electrically insulates the anode from the closure. The closure is connected to the housing by a pressure joint in the aperture of the housing. The closure electrically connects the cathode to the housing.
In accordance with another aspect of the invention, a method is provided comprising providing an anode, a cathode and dielectric material through an aperture of a capacitor housing; and inserting a closure into the aperture of the capacitor housing, wherein the closure electrically connects the cathode to the capacitor housing.
In accordance with another aspect of the invention, a method is provided comprising providing a capacitor comprising a cathode electrically connected to a housing of the capacitor by a closure, wherein the closure is located in an aperture into the housing, and wherein the cathode extends pasts opposite side of the closure; and connecting the cathode to ground to thereby electrically connect the housing to ground.
The foregoing aspects and other features of the invention are explained in the following description, taken in connection with the accompanying drawings, wherein:
Referring to
In one embodiment, the device 10 is an imaging device, such as a digital camera. Alternatively, the device 10 could be any suitable type of device having a capacitor as further understood from the description below. For example, in one embodiment the device 10 is a mobile telephone handset having a digital camera feature. The device 10 generally comprises a battery 18, circuitry 12, one or more capacitors 40, and a function 14. For the imaging device 10 in this embodiment, the function 14 comprises suitable hardware and perhaps software for taking a digital photograph. However, any suitable function which uses a capacitor could be provided. Referring also to
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The closure 54 forms a seal to close the aperture 58 and retain the dielectric material and portions of the anode and cathode inside the housing 46. In this embodiment the closure 54 is provided as a one piece member comprised of electrically conductive material. In the embodiment shown the material is a resiliently deflectable polymer or rubber material. The closure has a general disk shape with two holes 60, 62 and an annular recess 64 along its outer side perimeter. The holes 60, 62 provide channels for the anode and cathode to pass through from the dielectric material to the exterior of the capacitor.
In this embodiment the capacitor also comprises an electrical insulator 56. The insulator 56 is provided between the anode 48 and the closure 54. The insulator 56 is located in the hole 60 and electrically insulates the anode 48 from the closure 54. In this embodiment, the insulator 56 has a general tube shape. However, in alternate embodiments any suitable shape or type of insulator could be provided.
A portion 66 of the housing 46 is deformed inward proximate the entrance aperture 58 into the annular recess 64. This locks the closure 54 in position in the aperture 58 to thereby close the aperture. This deformation creates a pressure joint between the closure 54 and the housing 46 which mechanically and electrically connects the closure with the housing. In an alternate embodiment the recess 64 might not be provided, such as if the portion 66 merely deforms the closure 54 inward without need for the recess 64.
Because the closure 54 is made of electrically conductive material, the closure 54 is able to directly connect the cathode 50 to the housing 46. Thus, when the cathode 50 is connected to the flex cable 44, the housing 46 can be automatically connected to ground through the closure 54, the cathode 50 and the flex cable 44.
In accordance with one aspect of the invention, an apparatus is provided such as a digital stand alone camera, or a multifunction device such as a mobile telephone handset, or a subassembly for a device, such as a camera module subassembly for example. The apparatus comprises circuitry 44, a camera 22 connected to the circuitry; and a flash 30 connected to the circuitry. The flash comprises a flash lamp 38 and a capacitor 40. The capacitor comprises a cathode 50 electrically connected to a housing 46 of the capacitor by an electrically conductive closure 54. The closure closes an aperture 58 through the housing. The cathode is connected to a conductor of the circuitry for connection to ground.
In accordance with one aspect of the invention, an apparatus 40 can be provided including a housing 46; an anode 48 extending into the housing; a cathode 50 extending into the housing spaced from the anode; and a closure 54 in an aperture of the housing. The closure includes electrically conductive material. The anode and cathode extend through the closure. The closure electrically connects the cathode to the housing.
In accordance with another aspect of the invention, an apparatus 40 is provided comprising a housing 46; an anode 48 extending into the housing; a cathode 50 extending into the housing spaced from the anode; a closure 54 in an aperture of the housing, wherein the closure comprises electrically conductive material, wherein the anode and cathode extend through the closure; and an electrical insulator 56 between the anode and the closure, wherein the insulator electrically insulates the anode from the closure. The closure is connected to the housing by a pressure joint 64/66 in the aperture of the housing. The closure electrically connects the cathode to the housing.
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As noted above, normal grounding methods used for a capacitor for a flash lamp include conductive tapes, conductive adhesives or mechanical parts, such as sockets. These methods require time on an assembly line, as well as not always being reliable.
The invention can use a conductive rubber or polymer seal for the capacitor to ensure good grounding of the capacitor body to a conductor via the cathode pin. The invention can provide better grounding, lower assembly time, and no need to change the majority of current manufacturing steps of the component. A novel feature of the invention can include usage of conductive rubber to seal the capacitor, or a similar component and, thus, ensuring good grounding of the body of the component. The invention can comprise a new structure, method and apparatus of an improved shielding of a solderable component.
With the invention a manufacturer can change a conventional capacitor rubber seal (made of electrically insulating material) to a conductive material which can then be used to make electrical contact between the capacitor body and the cathode pin. This can be used to fulfill new safety requirements noted above. Also, adding one insulator part 56 can keep the anode electrically separated from the capacitor body. In one type of embodiment, electrically separating the anode from the capacitor body can be done by having the rubber seal being only partially conductive. When the capacitor is manufactured, the housing body can be punched at 66 to keep the seal in place. With this punch, the capacitor body can make a permanent electrical contact with the conductive rubber. The electrically conductive rubber will make a connection between the cathode wire and the capacitor ground body, and then no other groundings are needed to fulfill the safety standard noted above. The rest of the assembly process is totally the same as capacitor manufactures currently use.
Advantages include a low cost to manufacture compared to current methods. There is no need for any extra space in the device. Reliability is increased and much more easy to handle in the assembly process. Grounding is now part of the capacitor and is done by the capacitor manufacturer instead of a flash module manufacturer. This also allows a possibility to have similar grounding between all xenon suppliers instead of every xenon module supplier having its own solution as currently done. In addition, if used in a mobile telephone handset (having a camera), then phone-level safety testing is not needed.
During capacitor assembly, the sealing rubber will be assembled on top of the capacitor for sealing it. After assembly, the metal body can be punched toward sealing the rubber tight to fix the rubber in place. By changing the rubber material to conductive material, it is possible to contact ground to cathode without any extra part. Also, use of the invention with current assembly methods will make electrical ground contact automatically. No extra contact or assembly is needed.
An electrical insulator part can be used to protect the anode wire. It is also possible to make the rubber-part only partially electrically conductive, so then this insulator part is not needed. Using different material when making capacitor shielding will fulfill the new standard, and also it will not need any tooling modification or new assembly methods. It should be noted that, although the invention was described above with reference to a capacitor used with a camera flash, the capacitor could be used in any suitable type of electrical device. In addition, features of the invention could be used in an electrical device which is not a capacitor.
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The first and second members 86, 88 each preferably comprise resiliently deformable polymer material. Thus, the housing 46 can be inwardly deformed or stamped to fixedly mount the closure 84 in the aperture into the housing. However, in an alternate embodiment the second member 88 might not comprise a resiliently deformable polymer material. The second member 88 electrically connects the housing 46 to the cathode 50. The first member 86 electrically insulates the anode 48 from the cathode and the housing.
Referring also to
One way to fulfill the safety standard noted above is to ground the capacitor body to the ground of the flash device made by a xenon module supplier. However possible solutions of grounding the capacitor body to the ground of the flash device made by a xenon module supplier are not very reliability or they will need extra tooling in production. Also, they would be costly and make production very slow. The invention, on the other hand, can provide the advantage of grounding a capacitor body to a shielding ground reliably and cost efficiently. Possible solutions of grounding the capacitor body to the ground of the flash device made by a xenon module supplier are also not particularly suitable in mass production and they need extra work and cost. Also they are not reliably enough.
Different ways to make contact between a capacitor body to the ground of the flash device made by a xenon module supplier include use of conductive tapes, conductive adhesives or mechanical parts. They all need separate assembly processes when making a flash module, and also they need extra parts, toolings and make an assembly line very slow.
For conductive adhesive the capacitor ground body could be connected to a flex cable using conductive adhesive. Problems, however, include curing time is very long (maybe hours) which makes the assembly process very slow, extra adhesive is needed and extra dispensers are needed, extra features for the flex cable is needed (some opening area to flex), and the increased size needs some controlling during the process.
For conductive tape, glue could be used between a flex cable and/or a cathode pin and the capacitor body. Problems include extra parts are needed and tape cutting tools are needed, an extra assembly process is needed, there are reliability problems in that the tape might be drop out from contacts points if adhesive is not good enough, and increased size of the final product.
For a mechanical contact between the flex cable and the capacitor, an extra mechanical part could be used to make contact between the capacitor and the grounding point. Problems include extra parts are needed and expensive cutting tools are needed, and an extra assembly process is needed, there are reliability problems with the capacitor tolerances varying a lot, so very good spring contacts are needed, and this increases the size of the final product.
For a mechanical contact between phone mechanics and the capacitor, an extra mechanical part could be used to make contact between the capacitor and the grounding point. Problems include extra parts are needed and expensive cutting tools are needed, an extra assembly process is needed, there are reliability problems with the capacitor tolerances varying a lot, so very good spring contacts are needed, this increases the size of the final product, and the whole device (such as a mobile telephone handset) needs to be tested relative to safety standards.
The invention can be used to provide a ground when the capacitor is manufactured. Thus, there is no need for the xenon module supplier to perform an extra manufacturing process to provide a grounding connection for a capacitor. The capacitor is automatically grounded when the cathode is connected to the flex cable. Thus, all the potential problems noted above can be overcome by use of the invention.
With the invention, the invention can be provided by a camera module manufacturer or a flash module manufacturer to a device manufacturer, such as a manufacturer of a mobile telephone handset for example. The invention could be used in suitable multifunction devices having a camera function with a flash. The invention can also be used in a stand alone digital camera rather than a multifunction device. The invention can also be used in a device other than for a camera function. The invention could be provided as a flash module configured to be inserted into a device as a single subassembly.
It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. For example, features recited in the various dependent claims could be combined with each other in any suitable combination(s). In addition, features from different embodiments described above could be selectively combined. Accordingly, the invention is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims.
