Abstract:
Surface optical characteristics, alpha-numeric markings and other design features of memory cards, flash drives and similar devices combine to provide the devices with unique outer appearances. In one example, markings are held a distance from a reflective surface such that reflections of the markings off the surface are visible adjacent the markings. In another example, a diffusely reflecting rainbow hologram is combined with such markings or other design features.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This is related to an application entitled “Customized Non-volatile Memory Device Packages” being filed concurrently herewith by Brewer et al. This related application is hereby incorporated herein in its entirety for all purposes by this reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     This invention relates generally to the packaging of small, hand-held portable re-programmable non-volatile memory cards, flash drives and other such devices, and, more specifically, to a combination of letters, numbers and/or other indicia with surface optical characteristics to form a unique overall appearance of such devices.  
         [0003]     Electronic non-volatile memory cards are used with personal computers, notebook computers, cellular telephones, personal digital assistants (PDAs), digital still cameras, digital movie cameras, portable audio players and other host electronic devices for the storage of large amounts of data. Such cards usually contain a re-programmable non-volatile semiconductor memory cell array along with a controller that controls operation of the memory cell array and interfaces with a host to which the card connected. Flash memory cards have been commercially implemented according to a number of well-known standards. Popular types include CompactFlash (CF), MultiMediaCard (MMC), Secure Digital (SD), and Memory Stick, each of which is a sold by SanDisk Corporation, the assignee hereof. These portable, hand-held memory cards are small, the largest length being 50 mm., the largest width 36.4 mm. and the largest thickness being 3.3 mm. More recently, even smaller memory cards have come to the marketplace, including the miniSD and TransFlash cards of SanDisk Corporation.  
         [0004]     Other small, hand-held re-programmable non-volatile memory devices have also been made to interface with a computer or other type of host by including a Universal Serial Bus (USB) connector plug. These are especially convenient since personal computers, PDAs and other types of hosts commonly include one or more USB connector receptacles but may not have a receptacle slot that accepts any of above identified standard memory cards. There are several USB flash drive products commercially available from SanDisk Corporation under its trademark Cruzer. USB flash drives are typically shaped differently than the memory cards described above but contain memory with the similar amounts of data storage capacity. The mid-sized Cruzer flash drives have an elongated shape with a length of about 70 mm., including the USB connector plug at one end, a width of about 18 mm. and thickness of about 8 mm. The trend is to make flash drives smaller.  
         [0005]     The memory card and flash drive devices contain markings on an outside surface that typically give the storage capacity of the memory therein, the name and/or trademark of the seller and possibly other design elements that significantly contribute to the overall appearance of the product.  
       SUMMARY OF THE INVENTION  
       [0006]     Briefly and generally, particular optical characteristics and design features are combined to provide products with unique outer appearances, particularly on the above-mentioned memory devices. Specifically, in one form, markings are carried by a transparent layer a distance from a background surface such that a reflection and/or a shadow of the markings are visible through the transparent layer a distance behind the markings and shifted slightly along the background surface. The markings are thereby viewed with a sense of depth. This may be combined with a hologram on the background surface, such as a diffusely reflecting rainbow hologram. In another form, a hologram is combined with other design features such as a partially transparent covering layer that has different degrees of light diffusive characteristics across its surface. Particular combinations of various surface optical characteristics, markings and other design features give unique appearances to the products.  
         [0007]     Additional aspects, advantages and features of the present invention are included in the following description of exemplary examples thereof, which description should be taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a perspective view a flash drive with a first example combination of visual components;  
         [0009]      FIG. 2  shows a cross-section of the flash drive of  FIG. 1 , taken at section  2 - 2  thereof;  
         [0010]      FIG. 3  is a perspective view a memory card with a second example combination of visual components;  
         [0011]      FIG. 4  shows a first cross-section of the memory card of  FIG. 3 , taken at section  4 - 4  thereof;  
         [0012]      FIG. 5  shows a second cross-section of the memory card of  FIG. 3 , taken at section  5 - 5  thereof; and  
         [0013]      FIG. 6  illustrates certain optical characteristics of a surface the memory card of  FIG. 3 . 
     
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0014]     A first embodiment of a product package according to the present invention is illustrated in  FIG. 1  to be implemented on a commercially available flash drive memory device. The flash drive includes a main body portion  11  that has one or more integrated circuit chips containing re-programmable non-volatile memory cells, and usually a separate controller integrated circuit chip. The controller is connected between the memory chips and an input-output connector, in this case a plug  13  according to the specifications for the Universal Serial Bus (USB). The plug  13  is typically inserted into a mating USB receptacle on a personal computer (PC), personal digital assistant (PDA) or other host system. Electrical contacts within the plug  13  then connect with corresponding contacts of the receptacle. Data is then transferred between the host and the memory chip(s) within the flash drive, through the plug  13 .  
         [0015]     As best seen from the section  2 - 2  of  FIG. 1  that is shown in  FIG. 2 , a plastic layer  15  covers at least a portion of an area of the device. In the flash drive illustrated, the circuit chips are within an elongated rectilinear metal shell forming the plug  13  at one end and having a hole  17  at its other end for attaching the device to a key chain, necklace or the like. The plastic layer  15 , in this case, surrounds the metal on all sides except for the plug  13 . But what is of most interest here is an area of the layer  15  that carries letters, numbers, and other forms of indicia, markings or design elements on its outer surface. In at least this area, through which the section  2 - 2  of  FIG. 2  is taken, the layer  15  contacts the outer metal shell  16  and is at least partially optically transparent so that the metal surface may be viewed through the layer  15 . In this example, the layer  15  is substantially optically clear. The indicia “USB Drive” specify the type of device, and “256 MB” the storage capacity of the memory within it. These indicia are preferably opaque, such as being a solid black or some other color, but can alternatively have some amount of transparency. Further, the indicia may include letters outlined in one color while the area within the outline is another color. Many variations are possible for the indicia to be viewed either as a reflection from the background surface  16  and/or as a shadow on it.  
         [0016]     As a result of the background surface  16  under the layer  15  normally being polished metal, in this specific example, it has a high degree of reflectivity. The thickness of the layer  15  under these indicia is made sufficient so that an underside of the indicia reflect off of the surface  16  and the reflection is visible in a position adjacent the indicia. This result is shown in  FIG. 1 . In  FIG. 2 , a portion  19  of these markings is shown to form a reflection  21  that is viewable through the layer  15  by an observer  23 . As the position or angle of the observer  23  changes with respect to the marking  19 , the position of the reflection  21  changes with respect to the marking  19 .  
         [0017]     The minimum desirable thickness of the layer  15 , and thus the minimum distance of the marking  19  from the reflective surface  16 , to bring about this optical effect varies with the particular application but will generally be between 0.3 mm. and 2.0 mm., somewhere between 0.5 and 1.0 millimeter being a practical minimum. If the layer  15  becomes too thick, such as in excess of something between 4 and 6 millimeters, the reflections can appear so far displaced from the indicia when viewed from certain angles that a visual connection between the reflections and the markings is not immediately apparent. A significantly different overall appearance from that of  FIG. 1  can result.  
         [0018]     In addition to the reflections, shadows of the characters and other indicia on the surface  16  may be visible under certain conditions. Shadows may become visible when the incident illumination is strong and collimated. The degree of reflectivity of the surface  16  affects the strength of the reflections and therefore whether shadows of the indicia are noticeable. Also, the distance between the markings  19  and the surface  21  affect whether the shadows appear to the viewer.  
         [0019]     Rather than using a polished metal surface  16 , it may be made less reflective, even diffusely reflective. The reflections may not then be as strong but they will appear to the viewer. A diffusely reflective rainbow hologram, as used in another embodiment described below, may also be positioned to form the surface  16 .  
         [0020]     The layer  15  need not be totally optically clear. For instance, the layer  15  can be tinted to a particular color to give the flash drive a different visual effect. This may attenuate the contrast of the reflections and/or shadows somewhat but not eliminate their visibility so long as the amount of tinting is kept low enough. The layer  15  can even be made to have a degree of light diffusion or scattering without eliminating the viewability of the reflections and/or shadows. As a further variation, different regions of the surface  16  and/or various regions of the layer  15  of a single flash drive can be made to have different visible characteristics. The appearance need not necessarily be uniform across the product surface.  
         [0021]     In the example of  FIGS. 1 and 2 , it is the back side of the same markings that are viewable from the front which are reflected from the surface  16 . Light enters the layer  15  through transparent areas surrounding the markings and is reflected off the surface  16  to illuminate the back side of the markings. The reflection is thus the same as what is viewed directly from the front appears spatially separated.  
         [0022]     As an alternative, an opaque layer could be placed in a small area behind the markings visible from the front and some other indicia or design then placed behind that opaque layer. It is the rear indicia or design that would then be illuminated and visible in reflection from the surface  16 , not what is visible directly from the front. The appearance would be quite different from what is shown in  FIGS. 1 and 2 .  
         [0023]     The outer surface of the layer  15  on which the markings are attached is not significantly reflective, so multiple reflections inside of the layer  15  are not visible from the surface  16 . If the layer  15  is made of a material having an internally reflective outer surface, however, several reflections of the markings may be visible at different levels behind the layer  16 . This also would significantly change the appearance of the product from what is shown in  FIGS. 1 and 2 .  
         [0024]     In the embodiment shown, nothing is printed or marked directly on the surface  16 . But this could be added, again likely to substantially change the appearance of the memory device that is illustrated in  FIGS. 1 and 2 .  
         [0025]     Although the cover  15  is illustrated in  FIG. 1  to be molded tightly around the main body portion of the flash drive, the cover may alternatively be made as a separate sleeve that is inserted onto the flash drive by hand or a simple machine. This is described in the concurrently filed application cross-referenced above.  
         [0026]     As a second embodiment of the present invention illustrated in  FIGS. 3-6 , a memory card  25  is packaged to have similar visual characteristics but includes additional features. The illustrated card  25  is a Memory Stick card but the packaging techniques described herein are not limited to any particular memory card. External electrical contacts (not shown) lie within grooves  27  on one side of the card and various markings are carried by an opposite side of the card. Alpha-numeric characters are printed on, or otherwise applied to, a top surface of a cover layer  29  that is transparent enough to view a background surface  31  through it.  
         [0027]     In this example, the background surface  31  is a front face of a reflective hologram film  33  that is adhesively attached on its opposite side to an underlying substrate  35 , such as a molded plastic surface of the card  25 . The hologram  33  is preferably a rainbow hologram, wherein polychromatic light incident on its surface  31  is diffusely diffracted into a rainbow pattern of different colors that are visible at various angles of view. This is illustrated by  FIG. 6 . The background color of the card viewed in ordinary interior or exterior light is therefore a spread of diffuse light with a predominate color that depends upon the angle of view. The thickness of the layer  29  is made to be within the range described above for the layer  15  of the embodiment of  FIGS. 1-2  and the card otherwise structured so that reflections and/or shadows of the markings on the top surface of the layer  29  are therefore also viewable on the reflective hologram surface  31 . A backside of a portion  37  of the top surface markings, for example, is reflected at  39  from the surface  31 . The rainbow holographic reflections appear in the background between the top surface markings and their reflections. This combination of effects provides a very attractive memory card. Other types of holograms can be used instead to bring about somewhat different visual effects.  
         [0028]     In the memory card  25  of this example, a roughened strip  41  is provided for the user to note by pencil or pen the contents of the data stored in the card&#39;s non-volatile memory, as in existing Memory Stick cards. This also diffuses and scatters any light passing through the strip  41 . Neighboring regions  43  and  45  can retain an absence of any significant light scattering characteristic or made to have a degree of light scattering that is visibly different from that of the strip  41 . In this example, the hologram film  33  extends under all of the regions  41 ,  43  and  45 . As a result, light reflected from the rainbow hologram surface  31  through these different areas of the layer  29  appear to have different textures.  
         [0029]     The layer  29  may be made substantially optically clear or may alternatively contain a color dye. This can additionally affect the overall appearance of the card  25  by a filtering effect of the colored layer  29  on the light reflected from the hologram surface  31 . As a further variation, only a portion of the layer  29  may be colored, or different portions can have different colors. Various combinations of the layer  29  with some degree of light scattering and/or coloring, the diffuse rainbow reflections of the hologram  33  and the reflections and/or shadows on the surface  31  of the markings on the outside of the layer  29  are visually pleasing for the memory card. Other variations discussed above with respect to the first embodiment of  FIGS. 1-2  can also be incorporated in this second embodiment of  FIGS. 3-6 .  
         [0030]     Although the memory card illustrated in  FIGS. 3-6  is shown to be constructed as a unitary unit, the layer  29  may alternatively be included as part of a separate sleeve that is inserted onto a molded memory core by hand or a simple machine. This is described in the concurrently filed application cross-referenced above.  
         [0031]     Although the various aspects of the present invention have been described with respect to exemplary embodiments thereof, it will be understood that the present invention is entitled to protection within the full scope of the appended claims.