Film layer, assembly and method for altering the appearance of a mobile station

A film layer for a mobile station that allows the appearance of the mobile station to be easily changed. The layer is thin enough to allow it to be positioned between the plungers on a plunger mat and the keys on a key mat of the mobile station. Flexibility of the film layer allows a key press to be transmitted through the film insert to one of the plungers, which in turn compresses a contact on a printed wiring board. Flexibility may be due to perforations around the keys of the key mat. Preferably, the film layer includes some visually detectable characteristic, such as a color, that is visible through openings or translucent portions of the key mat. The film layer may be constructed of various materials, such as paper, elastomer, polymer or electric luminescent materials which can be interchangeably inserted into the mobile station to change its appearance.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to the manufacture and use of mobile stations (e.g., mobile telephones), and more particularly to interchangeable components for varying the appearance of the mobile stations.

2. Description of Related Art

Participants in the mobile telephone industry are in a constant search to differentiate their telephones by making them easier to use and more aesthetically appealing. For example, mobile telephones have been developed with easily interchangeable covers. An interchangeable cover allows the user to change the appearance of the phone as desired, such as by matching the cover to an outfit. Of course, the color or appearance of the cover is generally limited to commercially available colors so true customization by the user is not possible.

As another example, U.S. Pat. No. 6,310,609 discloses a user-interface with guide lights. The user interface includes a means for identifying the appropriate keys on the key mat which correspond to the step or steps required to activate a desired operation to be performed by the device. Identification of the appropriate keys is achieved using a light source which is mounted beneath each translucent key so that when the light source is illuminated, the key associated with that light source will be identifiable by the user.

The intensity of the light sources is variable and may be controlled to provide sufficient contrast to read all keys in low ambient light while highlighting the keys to be pressed for operation of the desired function. In high ambient light, the intensity of the guide lights may be increased for enhanced contrast and visibility. Alternatively, different color light sources may be used, with one color to light all keys for visibility in low ambient light, if needed, and the other color to provide the guide lights.

In yet another example, U.S. Pat. No. 6,466,299 discloses a cover for a mobile station constructed using thermochromic crystals. The thermochromic crystals are sensitive to changes in temperature, responding to such changes with changes in color. Application of the crystals to the cover of the station, or the keys on the key mat, allows the user to see which of the keys have been pressed or whether the phone has been recently used without authorization. In addition, the color changes have the advantage of being aesthetically attractive, differentiating the telephones from others on the market.

Despite all of the above-listed improvements in mobile station appearance and function, further improvements are still desirable.

It would therefore be advantageous to have a mobile station with an improved aesthetic appearance. It would be further advantageous to have a mobile station with an easily alterable aesthetic appearance. In addition, it would be advantageous if the aesthetic appearance could be non-commercially customized by the user.

BRIEF SUMMARY OF THE INVENTION

The present invention addresses the above needs and achieves other advantages by providing a film layer for a mobile station that allows the appearance of the mobile station to be easily changed. The film layer is positioned between the plungers of a plunger mat and the keys of a key mat of the mobile station. Flexibility of the film layer allows a key press to be transmitted through the film layer to one of the plungers, which in turn compresses a contact on a printed wiring board. Such flexibility may be implemented, or aided, by lines or areas of weakness (e.g., perforations) in the film layer that extend at least partially around the keys of the key mat. Preferably, the film layer includes some visually detectable characteristic, such as its color or a symbol, that is visible through openings or translucent portions of the key mat and/or a cover of the mobile station. Various materials may be used to construct the film layer, such as paper, elastomer, polymer or electric luminescent materials which can be interchangeably inserted into the mobile station to change its appearance. The keys may extend over a sufficient area to cover multiple plungers, so as to improve visibility of the film layer under the keys.

A mobile station of one embodiment of the present invention includes a housing and a wireless communications signal processing assembly positioned in the housing. The signal processing assembly has a plurality of pressure-sensitive areas, each of which is capable of registering an input. A film layer is positioned in the housing so as to overlie the pressure-sensitive areas of the signal processing assembly and includes at least one visually detectable characteristic. Also positioned in the housing is a key mat overlying the film layer. The key mat has a plurality of keys wherein each of the keys is positioned relative to a corresponding one of the pressure sensitive areas. In this manner, depression of a key deflects a portion of the film layer and similarly depresses the corresponding pressure-sensitive area.

Preferably, the film layer has at least one visually detectable characteristic (e.g., one or more colors, symbols, patterns or luminescent qualities). In this aspect, one or more portions of the housing of the mobile station, or the key mat, are sufficiently translucent to allow viewing of the visually detectable characteristic. For instance, the keys of the key mat and/or portions of a top cover of the housing may be constructed of optically transparent silicone.

The signal processing assembly may include a printed wiring board and a plunger mat. The printed wiring board has a plurality of contacts and the plunger mat has a plurality of plungers correspondingly positioned so as to overlie the contacts. Together, the contacts and the plungers define the pressure sensitive areas.

The film layer may have characteristics that facilitate deflection of the film layer in proximity to the keys. For instance, the film layer may include weakened areas in proximity to the keys. Such weakened areas may include areas of thinner material, areas of greater flexibility or areas surrounded by perforation lines. The perforation lines can be full or partial depth perforations defined in the film layer. The perforation lines may extend around at least a portion of a periphery of each of the keys so as to provide additional flexibility while being masked by an overlying portion of the housing.

In another embodiment, the present invention includes an assembly for custom manufacture of a film layer that alters a visual appearance of a mobile station. Included in the assembly is a film blank having a visually detectable characteristic. Also included in the assembly is a die having a cutting edge capable of cutting through the film blank to form the film layer. In addition, the cutting edge is shaped to cut the film in a size and shape to overlie at least some of the plungers of a plunger mat of the mobile station.

In another aspect, the cutting edge may be configured to cut perforations in the film blank that form areas of weakness in the film layer. The cutting edges may be further configured to cut perforations that extend at least partially around a periphery of each one of a plurality of keys of a key mat corresponding to the plungers. Optionally, the film blank may be capable of bearing print or symbols applied by a printer.

The present invention has many advantages. The flexibility of the film layer allows for key presses to be transmitted through to the plungers of the plunger mat. The film layer allows quick, easy and inexpensive changes to the appearance of a mobile station. Customization can even be performed on an individual level using practically any available film material. Also, the film material may bear indicia or symbols of ownership so as the promote a distributor or third-party. Separation of the plunger mat from the key mat allows the film layer to be seen through the keys. Use of a transparent silicone for the key mat promotes visibility of the film layer. In addition, use of broad keys that cover multiple plungers allows the film layer to be seen in relatively large, unbroken portions.

DETAILED DESCRIPTION OF THE INVENTION

A mobile station10of one embodiment of the present invention is shown in the exploded view ofFIG. 1. Among other components, the mobile station includes a bottom cover11, a printed wiring or other circuit board12(shown in an alternative embodiment illustrated inFIG. 4), a plunger mat13, a film layer14, a key mat15having a plurality of keys20, a top cover16and a display or view screen17. Advantageously, the visual appearance of the mobile station can be changed or customized by a user by exchanging the film layer14for other film layers, as will be described in more detail below.

It should be understood, that the mobile telephone illustrated and hereinafter described is merely illustrative of one type of mobile station that would benefit from the present invention and, therefore, should not be taken to limit the scope of the present invention. For example, other types of mobile stations, such as portable digital assistants (PDAs), pagers, laptop computers and other types of voice and text communications systems, can readily employ the present invention. Moreover, the system and method of the present invention will be primarily described in conjunction with mobile communications applications. But the system and method of the present invention can be utilized in conjunction with a variety of other applications, both in the mobile communications industries and outside of the mobile communications industries.

The bottom cover11and top cover16together form a housing for the remaining portions of the mobile station10. In other words, the covers collectively form a protective case in which the printed wiring board12, plunger mat13, film layer14, etc. are housed. Although the top cover may be constructed in various manners, the top cover may have a roughly rectangular shape with relatively thin walls formed of a plastic material. A plurality of openings are defined in the top cover, including a display opening18and a plurality of key openings19.

In the illustrated embodiment, the display opening18is the largest opening and is defined by the upper portion of the top cover. In addition to providing an opening for visibility of the view screen17, a lower portion of the display opening allows protrusion of one of the keys20of the key mat15. Each of the key openings19allows a respective one of the remaining two keys20to protrude and be accessible through the top cover16. In the illustrated embodiment, the top cover16also has side walls long enough to extend over the film layer14and the key mat15.

The bottom cover11of the illustrated embodiment mates with the top cover16and holds the plunger mat13, the printed wiring board12, the view screen17and other conventionally known components (battery, microphone, processor, etc.) necessary for the mobile station to receive, process and generate wireless communications signals. Collectively, these components will be referred to herein as a wireless communications signal processing assembly which, being known to those of skill in the art, are not described in greater detail herein.

Both the bottom and top covers11,16are preferably constructed of a relatively hard plastic material that is both light weight and protective. The covers, and in particular the top cover, may also be constructed partially or entirely of a translucent or transparent material that allows viewing of the film layer14, as described below. In addition, the housing is not necessarily limited to a collection of covers or any particular shape, material or configuration as long as the remaining components of the mobile station10are held together in a manner sufficient to operate.

The printed wiring board12, as shown in the alternative embodiment ofFIG. 4, includes a plurality of metal dome contacts21that allow a user to provide inputs to the processing assembly. Each of the contacts performs one or more allotted input functions, such as entry of a number for dialing or paging through menu selections. Movement of the dome contacts21is preferably in fractions of a millimeter, and more preferably 0.2 mm or less (in the vertical direction for the orientation of the mobile station10depicted inFIG. 1) allowing relatively small movements to register an input.

The plunger mat13includes a plurality of plungers22and is positioned so as to extend over the contacts21of the printed wiring board12. Although it may be configured in different manners, each of the plungers22of the illustrated embodiment includes a central disk portion23around which extends a conical skirt24which exerts a bias on the central disk portion that extends in a direction away from the printed wiring board12, i.e., upward in the orientation ofFIG. 1. Each of the plungers22is positioned above a corresponding one of the dome contacts21of the printed wiring board12. In addition, each of the plungers22is isolated from the remaining plungers so as to reduce mechanical cross talk between the plungers.

During the application of pressure from one of the keys20, the bias of the conical skirt24is overcome and the disk portion23is depressed. As the plunger is depressed, contact is made with the underlying dome contact21and an input is detected by the printed wiring board12. Preferably the plunger mat13is constructed of an elastic material to facilitate exertion of bias by the skirt24and flexibility during the depression of a key. For instance, silicone could be liquid injection or compression molded to form the mat13and the plungers22thereon. Other materials, however, could also be used such as a metal foil or other polymers.

It should be noted that in addition to the contacts21and plungers22, other devices could be used to sense the application of pressure. For instance, piezoelectric tablets could be positioned on the printed wiring board12to record depression of the keys20. Therefore, pressure sensitive areas as used herein in reference to the wireless signal processing assembly, and its component parts, refers to a device, or collection of devices, or other structure capable of recording the application of pressure, typically produced by the depression or actuation of one of the keys, for the purpose of registering an input to the processing assembly.

Supported in an adjacent and relatively coplanar position with respect to the plunger mat13is a view screen support frame27. The support frame supports the view screen17and associated electronic components needed for its operation. Also supported within the support frame27is an audio speaker assembly which is evident from a plurality of audio speaker openings28. As is conventionally known, the speaker assembly generates sound in response to signals from the signal processing assembly. The openings28allow the sound to be easily heard by the user.

As shown inFIG. 2, one embodiment of the film layer14is constructed of a thin layer of sheet material that extends substantially the length of the plunger mat13, view screen17and bottom cover11over which it is to be positioned. The film layer14may include a rounded or chamfered peripheral edge25extending around and defining a relatively flat central portion26. The central portion may define a second plurality of audio speaker openings29clustered together in a group to correspond to, and overlie, the openings28in the view screen support frame27.

Also defined by the central portion26is a view screen opening30sized to receive or otherwise expose the view screen17over which the film layer14is positioned. In the illustrated embodiment, for example, the view screen opening30has a rectangular shape to match the generally rectangular shape of the view screen17.

The central portion26of the film layer14also defines a number of regions that are generally associated with respective keys. Each region, as described below, is designed to be somewhat flexible or movable relative to other portions of the film layer such that the depression of a key activates a corresponding plungers and, in turn, a corresponding contact in the printed wiring board12.

In the illustrated embodiment, the film layer defines a plurality of perforation lines. The perforation lines are in three pairs extending along the bottom half of the film layer14. Each pair includes a first perforation line32and a second perforation line33. The first perforation line32has a smoothly curving M-shape with the free-ends of the legs of the M extending towards the bottom of the mobile station10. The second perforation line33extends in a smooth arc with its convex end directed downwardly, and its free ends extending in close proximity to the free ends of its respective first perforation line32. The space between the free ends of the first and second perforation lines32,33defines a film material tab34.

Although the illustrated embodiment defines an M-shape and an arc shape, it should be noted that the perforation lines may have other shapes. In addition, it should be noted that each pair of first and second perforation lines32,33has a shape that is congruent with the respective one of the keys20with which the regions of the film layer defined by the perforation lines is aligned. Advantageously, the perforation lines32,33extend around the periphery of the keys20(each of which has a kidney shape), so that the perforation lines cannot be seen through the keys. The perforation lines32,33provide areas of weakness for the keys so that a key press is transmitted through the film layer14to the plunger mat13, and through to the selected one of the contacts21.

Other configurations for the keys20could also be employed with the film layer14. For instance, a separate key could be used with each number, symbol or other function, in which case there could be more perforations to define a different region of the film layer for every key. In another example, different key sizes could be used for different numbers or functions requiring larger and smaller regions defined by perforations.

Regardless of the particular configuration, the tab34between the free end pairs of the perforation lines32,33serves to retain the portion of the film layer circumscribed by the perforation lines within the bounds of the perforation lines. As an alternative to the tabs, the perforation lines could be partial depth perforation lines that do not completely extend through the film layer14. Even if the entire periphery of the keys were traced by partial depth perforation lines, the region of the film layer circumscribed by the perforation lines could be flexed while remaining attached to the remainder of the film layer.

As another alternative, the film layer14itself could be manufactured so as to have portions with selectively positioned areas of weakness or increased flexibility, such as by reducing the amount of cross-linking between polymer chains in areas positioned under or around the keys20. As still another alternative, selected areas, i.e., those areas aligned with the keys20, could be manufactured with a reduced thickness so as to allow improved transmission of key press forces.

A range of different materials may be used to construct the film layer14and the term “film” is used herein to broadly indicate any sheet material which is thin enough to deform or otherwise transmit pressure or movement of key presses. For instance, the film layer14could be constructed of a paper, elastomer, polymer and electric luminescent materials. Another desirable characteristic for the film layer is aesthetic appeal including its colors, patterns or the ability to bear marks or indicia. The film can be imbued with color or patterns through such processes as silk screening, dying processes, printing, or may inherently have the color and properties that make it visually appealing.

A specific example of a film material useable for the film layer14is Bayfol CR 1-4 which is an extruded film made from a polymer blend of polycarbonate (PC) and polybutyleneterephthalate (PBT) manufactured by BAYER. The nominal thickness of the film is 0.125±10% mm. Another example is a paper type film that is electric luminescent so as to form lighted patterns when subjected to an electrical current (available from Miller Engineering of New Canaan, Conn., USA).

Manufacture of the film layer14in one aspect includes taking blanks of film material, forming them in a compression molding process and then using a die to cut a film layer of the desired size and shape from the film blank. In addition, the die cut can define the audio speaker openings29, the view screen opening30and the perforation lines32,33. In another example, the film layer14can be manufactured by injection molding the material in liquid form into a mold having a cavity shaped to form the film layer14. The various openings can then be defined using a die, or may be part of the mold itself.

The film layer14preferably has a visually detectable characteristic that, as will be described in more detail later, can be seen through the overlying key mat15and/or top cover16. Examples of such visually-detectable characteristics include indicia, such as the user's name, a company name, a trade mark or symbol, etc. Visually detectable characteristics also include colors, patterns, luminescence, reflective qualities, etc. Visually detectable characteristics, therefore, include any of a range of colors, images, indicia or other visible depictions or characteristics that allow improvement or customization of the mobile station's appearance or communicates information about the mobile station, such as an owner or distributor.

Similar to the film layer14, the key mat15has a shape, such as a rectangular shape, corresponding to the top cover16, as shown inFIG. 3. The key mat includes multiple keys20and, in the illustrated embodiment, a transparent lens35designed to overlie the visual display17. In the illustrated embodiment, the keys20are broad, kidney shaped keys extending between the left and right edges of the key mat15. However, the key mat can include other numbers and types of keys such as a more conventional key mat including ten, twelve or more keys, ten of which are each associated with a respective numeral from 0 to 9.

Around the transparent lens is a frame or bezel36for supporting the lens35. The bezel36also defines a cluster of audio speaker openings40that correspond in shape and position to the openings29in the film layer14.

Each of the keys20of the illustrated embodiment is capable of depressing multiple ones of the plungers22, and in particular, the bottom two keys are each capable of selectively transmitting pressure to any one of six plungers. As described below, however, each key can correspond to a different number of plungers, as desired, or even a single plunger. Ten of the twelve plungers selectable by the bottom two keys typically correspond to Arabic numerals used to dial telephone numbers, but of course can be customized with different functions or different numbering or lettering. In fact, such functions could be indicated by indicia on the underlying portions of the film layer14. The remaining two plungers are typically used to activate special symbols such as the “*” and “#” symbols. The top key corresponds to four plungers that are generally allocated to an answer/hang up key and menu selection keys allowing the user to page through various menus on the screen17.

In the illustrated embodiment, the keys20are constructed of a transparent material that renders the film layer14clearly visible. Preferred materials for the keys20include a clear silicone material or other transparent or partially translucent (i.e., permits the passage of some light) material with sufficient elasticity to locally deform when pressed with a fingertip. The clear silicone has the advantage of being completely transparent and relatively elastic so that individual ones of the plungers22may be depressed without exerting sufficient pressure on the remaining plungers under the key to activate the remaining plungers. Advantageously, having each key cover several of the plungers allows the keys to be relatively large and when combined with transparency, gives a clear view of any visible characteristics of the film layer14.

It should be noted that the keys20could also be smaller or larger, and have different shapes, depending upon the number of plungers22depressible by the keys. For instance, a one-to-one ratio of keys to plungers could be used wherein the keys20need not have any flexibility at all and could be made of a transparent polycarbonate, glass or other material. Of course, unlike the illustrated multiple plunger keys, larger indicia or symbols may not be as clearly visible through the relatively smaller keys.

In addition, at least a portion37of the bezel36may also be constructed of a transparent material to allow the film layer to be visible. The clear or partially translucent bezel portion can be constructed of a relatively hard plastic or polymer matched to the properties of the remaining portions of the bezel. As another alternative, the entire key mat15may be constructed of one or more transparent or translucent materials. Notably, even when the entire key mat is transparent, if the top cover is not transparent, the perforation lines32,33will not be visible.

A user can therefore change the appearance of the mobile station10by first detaching the top cover16from the bottom cover11revealing the internal components. The key mat15is removed from the existing film layer14if there is film layer, or from the plunger mat13if there is no film layer. The new film layer14is then positioned over the plunger mat13so that the perforation lines32,33extend around the respective groups of plungers22corresponding to the keys20.

The key mat15is positioned so that the keys20fall within the borders of the perforation lines32,33and the top cover16is reattached to the bottom cover11, typically snapping on through an interference fit, or being more firmly attached with fasteners. As the top cover16is attached, it is positioned so that the keys20extend through the-key openings19and the view screen17can be seen through the display opening18. In this manner, the portions of the cover16that extend between the key openings block visibility of the perforation lines32,33. After reassembly, the appearance of the mobile station10has been changed by the new visual characteristics of the film layer14which can be seen through the clear keys20and the clear bezel portion37. The user can subsequently again change the film layer if the user desires to further alter the appearance of the mobile station.

Illustrated inFIG. 4is an alternative embodiment of the mobile station10that includes a film layer14manufactured in two separate portions or sheets. A first sheet38is positioned to correspond to a view screen17and supporting frame27that are disposed in a separate plane displaced from the plunger mat13. The first sheet defines the view screen opening30similar to the embodiment inFIG. 1. A second sheet39extends over the plungers and unlike the embodiment illustrated inFIG. 1, does not include perforation lines32,33. Perforation lines are not needed for the second sheet39to transmit movement to the plungers22because the bottom sheet has been die cut but not molded so that it remains relatively flat. Generally, a relatively flat film layer14will be more flexible than a film layer of identical sheet material that has been molded.

In another embodiment, an end-user of the mobile station10can be empowered to customize the mobile station by manufacturing his or her own film layer14. For instance, the end-user may be provided with a kit including film material blanks and a die configured to cut the blanks into the shape necessary for use as the film layer. The material blanks may be printed using a desktop printer so that they bear indicia, symbols or other visual cues designed by the user (e.g., a monogram of the user's name positioned to be under each of the keys20). Alternatively, the end-user may obtain their own materials for construction of the blanks so as to have truly one-of-a-kind colors, patterns and other visible characteristics for individualizing the mobile station10. Preferably, for less flexible materials the dies include edges for defining the perforation lines32,33.

The present invention has many advantages. The film layer14allows quick, easy and inexpensive changes to the appearance of a mobile station10. Customization can even be performed on an individual level using practically any available film material. Also, the film material may bear indicia or symbols of ownership so as the promote a distributor or third-party. The indicia may also indicate functions of the various keys20beneath which they appear. Separation of the plunger mat13from the key mat15allows the film layer14to be seen through the keys20. Use of a transparent silicone or other transparent or partially translucent material for the key mat15promotes visibility of the film layer14. In addition, use of broad keys20that cover multiple plungers22allows the film layer of one embodiment to be seen in relatively large, unbroken portions.