The present invention generally relates to portable electronic devices and more particularly to a method and apparatus for changing the appearance of the portable electronic device housing.
The market for electronic devices, especially personal portable electronic devices, for example, cell phones, personal digital assistants (PDA's), digital cameras, and music playback devices (MP3), is very competitive. Manufactures are constantly improving their product with each model in an attempt to cut costs and to meet production requirements.
The look and feel of personal portable electronics devices is now a key product differentiator and one of the most significant reasons that consumers choose specific models. From a business standpoint, outstanding designs (form and appearance) may increase market share and margin.
Consumers are enamored with appearance features that reflect personal style and select personal portable electronics devices for some of the same reasons that they select clothing styles, clothing colors, and fashion accessories. Consumers desire the ability to change the appearance of their portable electronics devices (cell phones, MP3 players, etc.). Plastic snap-on covers for devices such as cell phones and MP3 players can be purchased in pre-defined patterns and colors. These snap-on covers are quite popular, and yet they provide a limited customization capability. The types of electro-optical modules that one could affix or embed in a portable electronic device to enable a changing appearance are limited by a number of factors. Portable electronic devices must be particularly thin, robust, and low power. As high volume consumer products, their sales are very sensitive to consumer preferences for design, functionality, and cost. These factors produce a narrow engineering window requiring unique solutions.
Portable electronics devices have curved surfaces, both in-plane (organically-shaped) and out of plane. The out of plane curved surface often contains compound curves. It is desirable to incorporate electro-optical modules into housings with these shapes such that the modules cover as much surface as possible, including the curved surfaces. When curves are involved, optical adhesives tapes typically used for liquid crystal displays will not work. It is furthermore desirable to fabricate thin panels, on the order of a millimeter or less to form housing elements, so electro-optical modules will need to be very thin, and will be fabricated on thin plastic substrates. These modules will need to be protected, so it is furthermore desirable to protect the outer surface of the electro-optical modules with highly transparent, high optical quality material that is thick enough to prevent damage to the electro-optical module via scratches, abrasion, and drop-testing, yet is comparatively as thin as typical housings. Furthermore, the interior components of portable electronic devices are typically connected to the housing by attachment points formed by molding, stamping or insert-molded. It is desirable to add these attachment points to the electro-optical housing. Incorporating electro-optical modules into shoes, watches, automobile doors, eye wear and cellular phones has been published, but solutions for these critical features have not been described.
However, many portable devices have complex, curved surfaces, and organic shapes. Electro-optic modules with curves cannot simply be laminated within these portable devices using conventional LCD optical adhesive techniques. The prior art manufacturing methods do not provide a low temperature molding process which keeps the mold costs low. The lower temperature requirements for the substrates require very long (expensive) injection molding times, or thousands or re-useable molds for a batch process, which is also expensive. In addition, consumers desire small, thin devices, which would require the electro-optic modules to be fabricated on thin plastic substrates which are thin and damage-prone.
Accordingly, it is desirable to provide a color-changing surface which is an integral part of a portable electronics device, and to provide a method for fabricating this apparatus which utilizes high volume, low cost methods. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.
Embodiments of the present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
An appearance-adaptable portable electronics device, e.g., a chameleon skin device, includes an electro-optical module embedded into the housing of the portable electronics device, allowing the use of thin, flexible, organically-shaped electro-optic modules within curved surfaces, while providing protection from the environment. These electro-optic modules, also known as flexible displays, are manufactured by depositing electronic devices as a thin film of a few micrometers on a polymer or metal foil substrate. The housing containing the electro-optical module disclosed herein provides an injection-molded or similarly formed housing which has metal frame structures inset molded into the housing to act as structural supports and attachment points for internal electronic components.
The electro-optical module provides an additional means for a user to interact with their electronic device. It communicates with them by presenting colors, patterns, and/or graphic and textual information in a reflective mode. The housing may also act as a ‘smart skin’, receiving input from the environment such as user touch responses, and it may sense temperature, ultraviolet light, gases, and the like and respond accordingly.
The method and apparatus described herein is performed at a low enough temperature (low temperature molding process) to be compatible with optical grade transparent flexible substrates such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), which tolerate about 150° C. for short periods of time. Their glass transition temperatures are 78° C. and 120° C. respectively, and melt below 260° C. Other transparent substrates also have low glass transition temperatures, for example, polycarbonate with a Tg of about 150° C. In contrast, known polycarbonate phone housings are processed at temperatures much higher than these, typically at temperatures greater than 300° C., and then rapidly cooled in order to speed up the injection mold time. The less time the injection molded part spends in the mold, the cheaper the finished part. While the parts are only at high temperature for 15-30 seconds typically, this would destroy devices built with PET and PEN substrates. In addition, injection molding typically produces very high shear forces, which can wrinkle thin substrates, especially at high temperatures.
The portable electronic device housing includes a transparent outer protective layer typically thicker than 50 micrometers, an electro-optical module, and a rear protective layer which may comprise attachment points for additional components. To produce thin housings, the electro-optical module is preferably manufactured on thin flexible substrates. The housings will typically have organic shapes such as ovals, rounded edges, or curves within the plane of the substrate sheets. They may also be conformed to a curved inner or outer protective layer, with these conformal curves being out of the plane of the substrate sheets. In a typical embodiment, the transparent outer protective layer defines at least one curve with a radius of curvature less than approximately 1.0 centimeter, and protects the electro-optical module from the environment, for example, puncture, scratches, water, and dirt, and is strong enough to withstand deep scratches and drops typically encountered with cell phone and MP3 player usage.
The method for manufacturing the electro-optical housing is compatible with the low temperature requirements of the flexible electro-optical module substrate material and a low enough cost for high volume manufacturing. Fabrication of the rigid shell, via injection molding or similar technique, is performed at a high temperature to increase the speed of the polymer injection and minimize the time in the mold. This shell then acts as a mold for lower temperature casting processes compatible with the electro-optical modules.
In order to avoid resin casting the modules into molds which would require thousands of molds for high volume portable electronics devices creating enormous tooling costs, the method of resin casting disclosed herein uses standard high temperature injection-molded (or metal insert-molded) parts, typically of polycarbonate to form the front protective layer or rear transparent layer. The transparent shell and support structure then act as a mold. The electro-optical module is low-temperature resin cast between them. Since molds are created for each part, they can be batch cured in an oven with no additional mold tooling needed. The resin casting approach provides an excellent method for assuring that the electrical input/output leads are accessible outside of the resin.
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.
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The adhesive material 112, for example an optical adhesive, cast resin, or curable polymer is optionally deposited on the rigid layer 102 within the cavity 108 before placement of the electro-optic module 105 by a nozzle (not shown) or any appropriate method known in the industry. This adhesive 112 is optically transparent to provide visibility of the viewable surface 111, and preferably has high optical quality and a good refractive index match to the electro-optical module 105. High optical quality includes the absence of significant scattering, haze, optical attenuation, and unwanted color shift. Alternatively, the electro-optical module 105 may be vacuum-cast (in the next step) into the housing 102 without the adhesive 112. A vacuum removes the gas which would otherwise form bubbles between the rigid layer 102 and the electro-optical module 105, and the cast material holds the module in place.
Another adhesive material 114, for example, an optical adhesive, cast resin, or curable polymer, is deposited on the electro-optical module 105. Adhesive material 114 may be selected from polyester, epoxy, carbon or glass reinforced epoxy, polydimethylsiloxane, urethane, polyurethane, silicone, and elastomers. This material 114 may be deposited by a nozzle, or may be vacuum-cast, or formed with other practices common in the industry. This material 114 is held in the vicinity of the electro-optical module 105 by the cavity shape of the rigid layer 102. Input/output leads 116 extending from the electro-optic module 108 for contacting module driver circuitry 116 extend away from the adhesive material 112, 114 so that they remain available for electrical contact. A portion of the electro-optic module 105 may be transparent to allow the passage of light from a light source, for example, a liquid crystal display, a light emitting diode, an organic light emitting device, and a transmissive light emitting diode display. In regions where the passage of light from the electro-optical module 105 is required, adhesive material 114 will be transparent and have high optical quality, and preferably have a refractive index that is well-matched to the electro-optical module 105. The adhesive material 112 and 114 are cured simultaneously. A thermal or catalytic cure often requires between 10 minutes and 10 hours. Ultra-violet light and related cures, which are often more expensive, require as little as 30 seconds. Curing can be accomplished in batch processes with thousands of housing units, thereby eliminating the extra cost per part associated with the longer cure times.
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An adhesive material 312, for example an optical adhesive, cast resin, or curable polymer is optionally deposited on the rigid layer 302 within the cavity 308 before placement of the electro-optic module 305 by a nozzle (not shown) or any appropriate method known in the industry. For regions where the electro-optical module 305 is designed to transmit light, the adhesive 312 preferably has a good refractive index match to the electro-optical module 305. Alternatively, the electro-optical module 305 may be vacuum-cast (in the next step) into the housing 302 without the adhesive 112. A vacuum removes the gas which would otherwise form bubbles between the rigid layer 302 and the electro-optical module 305, and the cast material holds the module 305 in place.
Another adhesive material 314, for example, an optical adhesive, cast resin, or curable polymer, is deposited on the electro-optical module or electro-optical module stack 305. The adhesive 314 is in contact with the viewable surface 311 of the electro-optical module 305 and is transparent in regions where the viewable surface 311 is designed to be observed. It is preferable that the adhesive 314 have a good refractive index match with the electro-optical module 305. Adhesive 314 functions as the outer protective layer for the electro-optical module 305, and as such, it is hard, scratch-resistant, and thicker than 50 micrometers to repel deep scratch damage. This adhesive material 314 may be deposited by a nozzle, or may be vacuum-cast, or formed with other practices common in the industry. This adhesive material 314 is held in the vicinity of the electro-optical module 305 by the cavity shape of the rigid layer 302. Input/output leads 316 extending from the electro-optic module 305 for contacting module driver circuitry 328 preferably extend under the back of the electro-optical module 305 and through a slit (not shown) in the inner support layer 302. A plate or tape covering the slit prevents the adhesive material 312 from contacting the electrical leads 316 so that they remain available for electrical contact. The adhesive materials 312 and 314 are cured. A thermal or catalytic cure often requires between 10 minutes and 10 hours. Ultra-violet light and related cures, often more expensive, can require as little as 30 seconds. Curing can be accomplished in batch processes with thousands of housing units, thereby eliminating the extra cost per part associated with the longer cure times. An optional hardcoat material (not shown) may be deposited on the outer surface of the adhesive 314 to improve mechanical durability.
The structure 100 of
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While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.