Abstract:
A housing ( 100, 300, 600, 700 ) for storing and protecting items comprises a photoreactive material ( 106 ) that selectively and irreversibly changes colors upon exposure to activating radiation ( 124, 324 ); and an ultraviolet attenuation coating ( 102, 702 ) disposed over the photoreactive material ( 106 ). Radiation ( 124, 324 ) is selectively applied to the photoreactive material ( 106 ) to irreversibly change the color of the photoreactive material ( 106 ) and therefore the housing ( 100, 300, 600, 700 ). An optional patterned layer ( 332 ) may be disposed between the photoreactive material ( 106 ) and the selective application of radiation ( 124, 324 ), and a background color ( 108 ) may be included, to affect the visual presentation of the housing ( 100, 300, 600, 700 ).

Description:
FIELD 
     The present invention generally relates to the use of photoreactive compound materials, and more particularly to the use of photoreactive compound materials to irreversibly change the appearance of a housing for a variety of devices. 
     BACKGROUND 
     The market for electronic devices, especially personal portable electronic devices, for example, cell phones, personal digital assistants (PDA&#39;s), digital cameras, and music playback devices (MP3), is very competitive. Manufacturers 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. 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. Sales of high volume consumer products are very sensitive to consumer preferences for design, functionality, and cost. These factors produce a narrow engineering window requiring unique solutions. 
     Accordingly, it is desirable to provide a method and apparatus for changing the appearance of a device housing. 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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
         FIG. 1  is a partial cross section view of a first exemplary embodiment; 
         FIG. 2  is a partial cross section view of a first exemplary embodiment having activating radiation applied; 
         FIG. 3  is a partial cross section view of a second exemplary embodiment having activating radiation applied; 
         FIG. 4  is a view taken along line  4 - 4  of the exemplary embodiment of  FIG. 3 ; 
         FIG. 5  is a view taken from the top of the exemplary embodiment of  FIG. 3 ; 
         FIG. 6  is a partial cross section view of a third exemplary embodiment having activating radiation applied; 
         FIG. 7  is a partial cross section of a fifth exemplary embodiment; 
         FIG. 8  is a top view of a device including the exemplary embodiment of  FIG. 2 ; and 
         FIG. 9  is a top view of the device of  FIG. 8  in accordance with a fifth exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     Housings are used to contain or store, and protect, a wide variety of items or devices and typically are a rigid or flexible material of a specific color. The term “housing” generally refers to a material at least partially covering or surrounding an item, and may assume other names such as a “case”, for example. Items disposed within a housing range, for example, from keepsakes such as jewelry to electronic devices such as cell phones. 
     The housing described herein includes a transparent support layer, a photoreactive coating, a radiation attenuating material, an optional background color layer, an optional activating radiation source, and an optional patterning layer. The transparent support layer provides structure to the housing. The radiation attenuating material, transparent to visible light, absorbs radiation, such as ultraviolet (UV) from sunlight, and prevents the unintentional changing of the color of the photochromic coating and degradation of the other layers beneath. The radiation attenuating material may be referred to as a blocking material when the UV radiation is substantially prevented from passing there through. When a slow color or design change is preferred, such as developing of patina effect, the UV blocking ability or efficiency can be engineered to allow, or attenuate, a limited amount of UV to reach the photoreactive layer to slowly activate the process. The photoreactive coating may be photochromic ink of a solution of a 1,2-dihydroquinoline (DHQ) in a polymer solution that irreversibly changes color when exposed to activating radiation such as UV radiation. The photoreactive material may also be a photosensitive layer containing silver oxalate and mercury(I) and/or mercury(II) oxalate. Another example is pyrrole derivatives, such as 2-phenyl-di(2-pyrrole)methane, which becomes irreversibly red upon UV light exposure. The photoreactive coating may originally comprise a color or be clear, and is changed to a color, or from a color to clear, upon the application of radiation. As used herein when referring to the photoreactive coating, the word “color” includes a visible color or no visible color (clear). The optional background color layer provides an initial color to the housing, and may be a partially reflective layer of metallization. The background color may be provided alternatively by the transparent support layer or may be omitted altogether when a transparent housing is desired (for displaying objects within the housing). The radiation source may be for example, a light emitting diode (LED), which emits light at specific wavelengths, for example ultraviolet or fluorescent black light, that activate the color changing process of the photoreactive compounds. While UV radiation is preferred, other wavelengths may be used. 
     Referring to  FIG. 1 , housing  100  includes a transparent support layer  104  having a UV blocking coating  102  formed thereon. While the transparent support layer  104  may be any known transparent material, a polymer material is preferred. The transparent support layer  104  provides protection to items within the housing, and a surface on which to apply the UV blocking coating  102  and the photoreactive coating  106 . The UV blocking coating  102  is a material that contains compounds, such as Benzotriazole or Benzophenone, that absorbs UV radiation found in the ambient environment, for example, in the range of  280  to  400  that includes both UV-A and UV-B, and especially UV radiation within sunlight. 
     The photoreactive coating  106  is a material of dye molecules that initially assumes a first color, then irreversibly changes to a second color upon the application of activating radiation. The second color remains when the activating radiation is removed. This material is, for example, preferably a matrix of 1,2-dihydroquinoline (DHQ) in polymer (See U.S. Pat. No. 4,812,171) or other materials such as a photosensitive layer containing silver oxalate and mercury(I) and/or mercury(II) oxalates, pyrrole derivatives, such as 2-phenyl-di(2-pyrrole)methane. 
     A transparent colored layer  108  is disposed contiguous to the photochromic coating  106 . The outer surface  110  of the UV blocking layer  102  is considered the outside of the housing while the inside surface  112  of the transparent colored layer  108  is the inside of the housing in which items (not shown) may be contained. Undesired UV radiation such as sunlight striking the surface  110  will not penetrate beyond the UV blocking coating  102  to the photochromic coating  106 . However, a user of the device viewing the outer surface  110  will view the color presented by the colored layer  108  since the UV blocking coating  102 , support layer  104 , and photochromic coating  106  are transparent to frequencies in the visual range of approximately 400 to 780 nanometers. Note that the colored layer  108  is optional, in which case the housing  100  is transparent, enabling the contents of the housing  100  to be viewed. 
     Referring to  FIG. 2 , a light source  122  such as a light emitting diode provides activating radiation  124  to the inside surface  112  of the housing  100 . The activating radiation  124  passes through the transparent colored layer  108  and strikes the photochromic coating  106 , causing it to irreversibly assume a color as indicated by the crosshatching within photochromic coating  106  of  FIG. 2 . The color in which the photochromic coating  106  changes depends on the chemicals contained therein and its thickness. Examples of chemicals for the irreversible photochromic coating  106  include 1,2-dihydroquinoline (DHQ) in a polymer solution, a photosensitive layer containing silver oxalate and mercury(I) and/or mercury(II) oxalates, pyrrole derivatives, such as 2-phenyl-di(2-pyrrole)methane. The thickness of the photochromic coating  106  preferably includes the range of 0.1 micron to 100 microns. The housing then exhibits the color, viewing towards the outside surface  100 , combined from the colors of the colored layer  108  and the photochromic coating  106 . For example, if the color of the colored layer  108  is blue and the color assumed by the photochromic coating  106  is yellow, a green color would be presented at the surface  110 . 
       FIG. 3  shows a second exemplary embodiment of a housing  300  including the UV blocking coating  102 , transparent support layer  104 , photochromic coating  106 , and transparent colored layer  108  as described for the housing  100 . A UV blocking layer  330  is patterned on the transparent colored layer  108  resulting in a light source  322  such as a light emitting diode provides activating radiation  324  through the patterned material  332  to the inside surface  112  in the gaps between the material  332  of the patterned layer  330 , causing the area  326  to change to a color (as indicated by the crosshatching). 
       FIG. 4  is taken along line  4 - 4  of  FIG. 3 , showing the patterned material  332  of the patterned layer  330  forming a fanciful pattern formed on the colored layer  108 .  FIG. 5  is the result showing the color and pattern looking at the surface  110  of the UV blocking coating  102  of the housing  300  in which the patterned material is distinctly seen through the transparent layers  104  and  102 . 
       FIG. 6  is a third exemplary embodiment of a housing  600  similar to the second exemplary embodiment of  FIG. 3 ; however, the colored layer  108  is disposed between the UV blocking coating  102  and the transparent support layer  104 . Note in this third exemplary embodiment, the colored layer  108  need not be transparent to the activating radiation. 
     Instead of the light sources  122 ,  322 , a fourth alternate exemplary embodiment includes a door, or sealable opening, that may be opened to allow sunlight to enter, striking the photochromic coatings  106 , causing it to change colors and/or pattern. 
     Referring to  FIG. 7 , a fifth exemplary embodiment includes a housing  700  having a UV attenuating layer  702  formed over the photochromic coating  106 , and the transparent support layer  104  disposed between the photochromic coating  106  and the colored layer  108 . The UV attenuating layer only partially blocks UV radiation, for example from sunlight, resulting in the color of the photochromic coating  106  slowly changing color over time. Depending on the thickness and the chemical makeup of the attenuating layer and the photochromic coating  106 , this change in color may take days to weeks or more. Additionally, the patterned layer  330  may be included to cause a change in pattern over time. 
     There are many variations to the above described embodiments. As mentioned, the colored layer  108  is optional (the housing may be transparent or the color may integrated within the transparent support layer  106 ) and may be disposed on either side of the support layer  104  or the photochromic coating  106 . The photochromic coating  106  may be disposed on either side of the support layer  104  or may be integrated within the support layer  104 . The disposition of the patterned layer  330  is also variable as long as it is disposed between the photochromic coating  106  and the source of radiation. 
     Although the housing  100 ,  300  described herein may be used to house many types of devices,  FIG. 8  shows in schematic form a mobile communication device, which may be used with the exemplary embodiments of the housing  100 ,  300  described herein, and includes a touchscreen display  812  formed within the housing  100 ,  300 . Conventional mobile communication devices also include, for example, an antenna and other inputs which are omitted from the figure for simplicity. Circuitry (not shown) is coupled to each of the display  812 , and typically a speaker and microphone (not shown). An icon  814  is disposed below the touchscreen display  812 . It is also noted that the portable electronic device  800  may comprise a variety of form factors, for example, a “foldable” cell phone. While this embodiment is a portable mobile communication device, the present invention may be incorporated within any electronic device having a housing that incorporates an electro-optical module to change colors and/or patterns. Other portable applications include, for example, a laptop computer, personal digital assistant (PDA), digital camera, or a music playback device (e.g., MP3 player). Non-portable applications include, for example, car radios, stainless steel refrigerators, watches, and stereo systems. The low power requirements of the exemplary embodiments, specifically the light source providing UV radiation, presented herein make them particularly well suited to portable electronics devices. 
     A sixth embodiment includes disposing an LED so as to irradiate only of a portion of the housing  100 ,  300 . For example, referring to the device  800  shown in  FIG. 9 , only the area  916  surrounding the touchscreen display  812  is irradiated (as shown by the cross hatching) by one light source  324 . Another light source  324  may selective irradiate the icon  814 . Although only two light sources  322  are described with the exemplary embodiment of device  900 , many more light sources  322  may be disposed within the housing  100 ,  300  to irradiate various portions of the device  900 . Additionally, the photochromic coating  106  may be disposed in selective positions, such as behind only the icon  918 , and then irradiated. 
     The exemplary embodiments described herein provides an easy, inexpensive way for users to irreversibly customize the appearance of a device&#39;s housing, while requiring little or no power requirements. 
     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.