Abstract:
A panel with an optically transmissive portion includes a group of holes drilled from one surface to another surface and filled with an optically transmissive material. The group of holes forms a pattern. The holes on a first surface form a smooth and continuous appearance to the naked eye. The holes on the other, second surface are sized so that a light source directed to the second surface illuminates the pattern to be visible to a viewer viewing the first surface. The panel may form a portion of a housing that houses the light source.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 13/797,891, filed Mar. 12, 2013, which is a division of U.S. patent application Ser. No. 11/742,862, filed May 1, 2007, now U.S. Pat. No. 8,394,301, which claims the benefit of U.S. Provisional Application No. 60/810,380, filed Jun. 2, 2006, each of which is incorporated herein in its entirety by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The disclosure herein relates to products with a patterned light-transmissive portion, such as a panel and/or housing with a patterned light-transmissive portion. 
       BACKGROUND 
       [0003]    Projecting a light through a housing to provide information is commonplace. Examples include but are not limited to computer keyboards that include indication lights for functions such as “Caps Lock” or “Num Lock”; computer monitors that include an “on/off” light automobiles that include lights to indicate whether heated seats are on or off, or whether an air bag is on or off; televisions with indicator lights, and a whole host of other consumer electronics. 
         [0004]    A common way to provide for such lighting is to provide a projecting light that is visible when the light is off and brightly lit to indicate when the light is on. A collection of lights, or holes for lights, may be disruptive to the objectives of an industrial designer. 
       SUMMARY 
       [0005]    Disclosed are methods for forming a display in a relatively thin substrate or panel with a material that permits the transmission of light through microholes filled with a transparent filler material and products that are made by such methods. 
         [0006]    One apparatus described herein includes a panel having a first external surface and an opposite, second external surface, wherein a material of the panel is non-transmissive to light, a pattern of microscopic holes drilled through at least a portion of the panel, wherein openings of the microscopic holes are sized such that light applied to the second external surface illuminates the pattern on the first external surface and the first external surface forms a continuous panel surface to the naked eye when light is not applied to the second external surface, and a light transmissive material filling the microscopic holes. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views unless otherwise noted. 
           [0008]      FIG. 1  is a schematic representation of the sequence of method of the present disclosure. 
           [0009]      FIG. 2  is a schematic representation of a conically-shaped via or hole geometry. 
           [0010]      FIG. 3  are SEM micrographs taken of a panel having conically-shaped vias showing the first or back side of a panel with the larger via opening. 
           [0011]      FIG. 4  are SEM micrographs of vias showing the second or visible side of the panel having the smaller opening of the conical via. 
           [0012]      FIG. 5  is a SEM micrograph of the visible side of the panel having the smaller opening of the exemplary vias with the filler material in the vias. 
           [0013]      FIG. 6  is an optical micrograph of the visible side of the panel having the exemplary vias filled with the filler material and having backlighting to show transmission of light through the conical vias as viewed from the visible side of the panel. 
           [0014]      FIG. 7  is an enlarged optical micrograph of the visible side of the panel shown in  FIG. 6 . 
           [0015]      FIG. 8  is a SEM micrograph cross-section of several vias filled with the filler material. 
           [0016]      FIG. 9  is an enlarged SEM micrograph cross-section of a filled conical via shown in  FIG. 8 . 
           [0017]      FIG. 10  is a schematic representation of an alternate configuration of the filler material on the visible side of the panel. 
           [0018]      FIG. 11  is a SEM micrograph of the alternate filler material configuration shown in  FIG. 10 . 
           [0019]      FIG. 12  is an optical micrograph of the alternate filler material configuration shown in  FIG. 11 . 
           [0020]      FIG. 13  is a schematic representation of an alternate configuration of the filler material on the visible side of the panel. 
           [0021]      FIG. 14  is a SEM micrograph of the alternate filler material configuration shown in  FIG. 12 . 
           [0022]      FIG. 15  is an optical micrograph of the alternate filler material configuration shown in  FIG. 14 . 
           [0023]      FIG. 16  is a schematic representation of an alternate configuration of the filler material on the visible side of the panel. 
           [0024]      FIG. 17  is a SEM micrograph of the alternate filler material configuration shown in  FIG. 16 . 
           [0025]      FIG. 18  is an optical micrograph of the alternate filler material configuration shown in  FIG. 17 . 
           [0026]      FIG. 19  is a schematic representation of a housing utilizing a light transmissive panel including filled vias. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Referring to  FIGS. 1-18 , methods for filling at least one via with a light transmissive material are shown and described below.  FIG. 19  illustrates a product resulting from one of the methods. The disclosure utilizes via drilling techniques to create a micro via that is then filled with a light transmissive material. Via drilling is known in the unrelated field of electronics manufacturing. Vias are created in multi-layered interconnected substrates and lined with a conductor, such as copper, to permit an electrical connection between different layers in a circuit. 
         [0028]    A method  10  and steps for filling a via with light transmissive material are illustrated in  FIG. 1 . A panel or substrate  12  is provided. Panel  12  as shown is a relatively thin continuous sheet of material. Panel  12  includes a first or back side  14  and an opposing second or front side  18  defining a panel thickness  20 . Front side  18  is relatively smooth and substantially unbroken to the naked eye. Panel  12  may be made from anodized aluminum or other materials known to those skilled in the art. 
         [0029]    The method  10  includes drilling one or a plurality of micro-vias or holes  30  through the panel  12 . As shown in  FIGS. 2-4, 8 and 9 , in one aspect of the method the vias  30  are conical-shaped having sidewalls  34  and a first opening  40  in panel first side  14  and an opposing second opening  44  on panel side  18 . First via opening  40  is larger in diameter than second via opening  44 . In one aspect, first via opening  40  is approximately 90-100 micrometers (μm) in diameter, and second via opening  44  is approximately 30-40 micrometers (μm) in diameter. It is understood that larger or smaller conical openings and other via shapes and configurations may be used. 
         [0030]    The vias shown are drilled or machined out of the panel using a laser  24 , such as a diode-pumped solid-state pulsed laser, in a circular or spiral pattern. It has been shown that a Nd:YAG 355 nm spot 22 with a pulse repetition rate of 30 kHz and ˜60 nanosecond pulse width is useful in machining out the preferred conical-shaped vias  30 . Drilling of the exemplary vias  30  is accomplished from back side  14  through panel  12  toward the front side  18 . Other types of lasers with different characteristics and other machining processes from drilling vias known to those skilled in the art may be used to suit the particular application. 
         [0031]    The method  10  optionally includes the step  46  of cleaning the drilled vias  30  to remove any debris or deposits formed during the machining process. It has been shown that a CO 2  snow jet cleaning and isopropyl are effective in cleaning the vias. Other via cleaning techniques known by those skilled in the art may also be used. For example, ultrasonic cleaning using, for example, ultrasonic baths may be used. Also, the application of high-pressure air, like the snow jet, may be made from a source movably located in a similar manner to the drill  24  to clean the vias. 
         [0032]    As shown in  FIGS. 1 and 5-9 , the method  10  includes applying a filler material coating  50  into the vias  30 . The filler material  50  may be a visible light transmissive material. As illustrated, filler material  50  is an optically transparent ultraviolet (UV)-curable, acrylate polymer that is in a liquid phase at the time of application to panel  12 . Other plastics or polymers with light transmissive properties may also be used. The exemplary UV curable filler material is substantially clear when cured. As best seen in  FIG. 1 , the filler material  50  can be applied to the panel second side  18  over the top of the second, optionally smaller openings  44 , of vias  30 . It has been observed that through the relatively low viscosity of the exemplary liquid phase filler material  50 , the geometry of the conically-shaped vias  30  and the forces of gravity, the filler material  50  flows into and through the vias  30  from the second side  18  to the first side  14 , effectively filling the vias  30  as best shown in  FIGS. 1, 8 and 9 . Excess filler material  50  may propagate on panel  12  second side  18  (shown as  66 ) and first side  14  (shown as  62 ) as best seen in  FIG. 1 . The filler material  50  as shown is applied with a syringe-type device  54 . Other filler material  50  application devices and techniques known by those skilled in the art may be used. Examples include ink jet techniques and pad printing techniques. 
         [0033]    In an alternate aspect, filler material  50  may be applied to back side  14  so the filler material  50  flows through via  30  from back side  14  toward front side  18  in a similar manner as described. 
         [0034]    When a curable filter material is used, method  10  may include the step  76  of curing the exemplary liquid phase silica-based filler material  50  by exposing the filler  50  to UV light. Exposure to UV light  76  initiates free-radical polymerization of the silicate filler material  50  inside and through vias  30 . In one method of applying the UV light, the UV light is applied to back side  14  and via  30  (i.e., the large openings  40 ) to promote curing of filler material  50  in vias  30 . When cured, the exemplary filler material  50  is optically transparent permitting passage of visible light through the filler  50  and panel  12  through vias  30 . 
         [0035]    Method  10  includes the step  82  of removing any excess or uncured filler material deposits  66  from the panel visible, front side  18  as shown in  FIG. 1 . For example, filler excess deposits  66  may be removed from front side  18  through a simple isopropanol wipe, leaving a visibly smooth and clean surface. Other methods and techniques for removing excess deposits  66  may be used. 
         [0036]    Method  10  may optionally include the step  90  of exposing the filler material  50  in vias  30  adjacent to the visible panel side  18  after the step of removing excess deposits  66  to assist curing of the filler material  50  throughout vias  30 . Referring to  FIG. 9 , the filler material  50  most adjacent to the panel visible surface  18  may be slightly below front side  18  forming a recess  94  between the filler  50  and front side  18 . 
         [0037]    As best seen in  FIGS. 10-18 , treatment of the filler material directly adjacent to the visible panel surface  18  may be varied to change or enhance the visual appearance of the filler material  40  and visible light passing therethrough for a user. In an alternate aspect of method  10 , cured excess filler deposits  66  may take a convex shape or form as opposed to being recessed into vias  30  as shown in  FIG. 9 . For example,  FIGS. 10-12  and  FIGS. 13-15  illustrate two such convex forms for the cured excess filler deposits  66 . In  FIGS. 10-12 , the convex shape extends beyond and surrounds the second via opening  44 . In  FIGS. 13-15 , the convex shape is approximately limited to the area of the second via opening  44 . Through different shapes or configurations, the visible light passing through the filler material  50  may be altered to produce a different visual appearance or effect to the user similar to altering the shape or configuration of a lens. As another example,  FIGS. 16-18  illustrate, instead of a concave or convex shape, a flush fill, that is, an embodiment where the filler material  50  is flush with the surface of the second, or front, side  18 . 
         [0038]    The cured filler material  50  and front side  18  from the method  10  results in protected vias  30  capable of transmitting light through panel  12 . The use of vias and an optically transparent filler material produces a smooth and continuous panel surface to the naked eye that is capable of displaying controlled images through the vias from interior illumination, as shown in  FIG. 19 .  FIG. 19  illustrates a panel  12  including a back light  70 , which may be an LED, fluorescent or incandescent light, or other lighting devices. Panel  12  may be a section inserted into a housing or may be an integral section of the housing  72  as shown in  FIG. 19 . 
         [0039]    The resultant panel  12  can be used in all manner of applications including hand-held electronic devices, for example, MP3 players, computers, cellular phones, DVD players and the like. The disclosed method and resultant panel is applicable in virtually all applications where a visually continuous and uninterrupted panel surface is desired having the capability to produce illuminated messages, images or other perceptible characteristics for the user. 
         [0040]    While the method has been described in connection with certain embodiments, it is to be understood that the method is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent steps and arrangements included within the scope of the invention and any appended claims.