Abstract:
The present invention relates to a method of eliminating and a laminate which eliminates an aesthetically unacceptable hue normally visible at an area of overlap between a light-colored substrate that reflects a certain wavelength of light back to and through a light-colored translucent overlay. Specifically, the method includes applying a dark material to at least one of the light-colored substrate and the light-colored translucent overlay upon an area of overlap of the substrate and overlay, and sandwiching the dark material between the overlay and the substrate at the area of overlap so that certain wavelengths of light normally passing through the overlay into the substrate and reflected by the substrate back to and through the overlay are blocked by the dark material. The light-colored overlay in the area of overlap appears in its true light color to the “naked” eye absent the aesthetically unacceptable hue.

Description:
THE TECHNICAL FIELD  
         [0001]    The present invention relates to the elimination of aesthetically unacceptable hues visible through light-colored translucent overlays, and more specifically to a method of eliminating and a laminate which eliminates the unacceptable hues that are created in an area of overlap between a light-colored substrate that reflects a certain wavelength of light to and through a light-colored translucent overlay.  
         BACKGROUND OF THE INVENTION  
         [0002]    Glass and glass-ceramic products are used commonly in the manufacture of, for example, cooktops, appliance and fireplace doors and windows, control panel and backsplash assemblies, refrigerator shelves, and laboratory equipment. In fact, conventional radiant cooktops are frequently manufactured with a light-colored glass-ceramic panel supported by a light-colored porcelain frame. In general, the glass-ceramic panel and the porcelain frame are the same color. Invariably during the manufacture of these radiant cooktops there is an overlap area between the glass-ceramic panel and the porcelain frame. It is in this overlap area that unacceptable hue colorations become visible. The hue colorations are the result of certain wavelengths of light passing through the glass-ceramic panel, reflecting off of the porcelain frame and passing back through the glass-ceramic panel. Common colors of the unacceptable hues include pink, purple and green, and the actual color of the unacceptable hue is dependent upon the wavelengths of light that pass back through the glass-ceramic panel.  
           [0003]    For example, when a white glass-ceramic panel is used with a white porcelain frame, the resulting overlap area between the two has an unpleasant pink hue that is visible to the “naked” eye of the consumer. In other words, the white porcelain frame behind the white glass-ceramic panel in the area of overlap appears to have a visible pink hue. Unfortunately, this pink hue is unacceptable, since it detracts from the otherwise totally white appearance of the cooktop.  
           [0004]    A method currently used to mask the unacceptable visible hue of such conventional cooktops involves placing a painted steel plate in the overlap area between the glass-ceramic panel and the porcelain frame. Unfortunately, this method is less than ideal since it adds unwanted material and manufacturing labor costs to the cooktop.  
         SUMMARY OF THE INVENTION  
         [0005]    One way to solve the problem of an aesthetically unacceptable hue being visible through an area of overlap between a light-colored translucent overlay and a light-colored substrate is by applying a dark material upon at least one of the light-colored substrate and the light-colored translucent overlay in the area of overlap therebetween. By thereafter sandwiching the dark material between the overlay and the substrate at the area of overlap, certain wavelengths of light that normally pass through the overlay into the substrate and would otherwise reflect off the substrate back to and through the overlay are blocked and/or absorbed by the dark material. As a result, the light-colored translucent overlay in the area of overlap appears in its true light color to the “naked” eye absent the aesthetically unacceptable hue.  
           [0006]    In a preferred embodiment of the present invention, the dark material is an adhesive which advantageously bonds the overlay and substrate together without the need for separate fasteners.  
           [0007]    With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is a top perspective view, and illustrates a prior art radiant cooktop having a glass and/or glass-ceramic panel disposed in a cooktop frame.  
         [0009]    [0009]FIG. 2 is an enlarged, fragmentary, cross-sectional view taken generally along line  2 - 2  of FIG. 1, and illustrates the stepped configuration of the cooktop frame including an inner peripheral wall upon which a peripheral edge of the glass and/or glass-ceramic panel is disposed, and incoming light passing through the panel being reflected by the frame back through the panel to the “naked” eye of a consumer.  
         [0010]    [0010]FIG. 3 is a top perspective view of a cooktop frame, similar to that shown in FIG. 1, and illustrates a dark material applied to an inner peripheral wall of the cooktop frame in accordance with the present invention.  
         [0011]    [0011]FIG. 4 is an enlarged, fragmentary, cross-sectional view taken generally along line  4 - 4  of FIG. 3, and illustrates the stepped configuration of the peripheral walls of the cooktop frame with the dark material disposed on the inner peripheral wall.  
         [0012]    [0012]FIG. 5 is a top perspective view of a radiant cooktop of the invention, and illustrates a glass and/or glass-ceramic panel disposed in the cooktop frame of FIG. 3 with the panel completely covering the dark material in the area of overlap between the panel and the cooktop frame.  
         [0013]    [0013]FIG. 6 is an enlarged, fragmentary, cross-sectional view taken generally along line  6 - 6  of FIG. 5, and illustrates the dark material blocking the reflection of and/or absorbing the incoming light passing through the panel in the area of overlap between the panel and the cooktop frame. 
     
    
     PRIOR ART  
       [0014]    The present invention will be best understood and its novelty and unobviousness appreciated by first describing a typical conventional cooktop possessing the disadvantages hereto discussed.  
         [0015]    A prior art radiant cooktop  10  (FIGS. 1 and 2) includes a porcelain frame  11  which supports a glass-ceramic panel  12 . Specifically, a white glass-ceramic panel  12  is shown disposed on a white frame  11  which results in the cooktop  10  having an unacceptable pink hue that is visible to the consumer in an area of overlap A (FIG. 2) between the white glass-ceramic panel  12  and the white frame  11 . This pink hue gives the impression that the white frame  11  behind the white glass-ceramic panel  12  is pink, which detracts from the otherwise overall white visual appearance of the cooktop  10 .  
         [0016]    The frame  11  includes a backsplash  13  which is generally perpendicular to and merges with a top  14 . The top  14  is generally defined by an outer peripheral wall  15  (FIG. 2), an inner peripheral wall  16  and one or more medial peripheral walls  17  all arranged to define a generally stair-step or stepped configuration. The outer peripheral wall  15  is generally perpendicular to and merges with an outer depending side wall  21  and a first medial depending side wall  22 . The first medial depending side wall  22  is generally perpendicular to and merges with the medial peripheral wall  17  which is generally perpendicular to and merges with a second medial depending side wall  23 . The second medial depending side wall  23  is generally perpendicular to and merges with the inner peripheral wall  16 . The inner peripheral wall  16  is generally perpendicular to and merges with an inner depending side wall  24  which defines an opening  18  of the white frame  11 .  
         [0017]    The white glass-ceramic panel  12  includes an exterior perimeter edge  25  which is disposed on the white inner peripheral wall  16 . The specific area of overlap A is between the exterior perimeter edge  25  of the white glass-ceramic panel  12  and the white inner peripheral wall  16  of the white frame  11 .  
         [0018]    Incoming visible light is shown by a first arrow line  27  passing through the white glass-ceramic panel  12  and reflecting off the white inner peripheral wall  16  and back out through the white glass-ceramic panel  12  along a second arrow line  28  substantially at which the reflected light can be viewed by a “naked” eye E. As a consequence of passing through the white glass-ceramic panel  12 , some of the wavelengths in the visible light spectrum are filtered out and the remaining unfiltered visible light wavelengths that are reflected back out along the second arrow line  28  cause the unacceptable hue coloration (for example, pink in the case of the white-on-white overlap just described). In the cases of other light color-on-light color overlaps, the exact color of the hue that is visible can vary and includes various shades of pink, purple and green.  
       DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]    In accordance with the present invention, a light-colored substrate is coated with a dark coating material in a shape that generally mirrors the exterior outline of a light-colored translucent panel that is disposed upon the substrate at an overlap area therebetween. Alternatively, the light-colored translucent panel is coated with the dark coating material in a shape that generally mirrors the interior outline of the light-colored translucent substrate upon which the light-colored translucent panel is disposed at the overlap area therebetween. In each case the dark material blocks the reflection of light passing through the panel in the area of overlap to prevent the creation of aesthetically unacceptable hues.  
         [0020]    The substrate can include, for example, a frame constructed of a porcelain enamel, coated or painted metal, or a plastic surface or a countertop surface made of standard kitchen building materials. In general, the color of the substrate is white, bisque, almond or any other light color that will reflect certain wavelengths of visible light that pass through the light-colored translucent panel back through the light-colored translucent panel. If otherwise unprovided for by dark coating material, it is this reflection that presents an unacceptable pink, purple or green hue in the area of overlap between the light-colored substrate and the light-colored translucent panel.  
         [0021]    The light-colored translucent panel can be a glass-ceramic or a tempered flat glass panel. A “glass-ceramic” is a glass that has a thermal expansion near zero due to submicroscopic crystalline growth that has been deliberately stimulated by heat treatment over a defined temperature-time profile. In general, the color of the panel matches the color of the substrate and can be white, bisque, almond or any other light color.  
         [0022]    The present invention can be used in the manufacture of cooktops, fireplace doors and windows, oven door windows, control panel assemblies, back splash assemblies, refrigerator shelves, laboratory hotplates and microwave oven doors where, by placing a dark material coating between a light-colored translucent panel and a light-colored substrate, an unacceptable hue in the area of overlap between the light-colored translucent panel and the light-colored substrate is completely eliminated. The actual color of the unacceptable hue that is imparted depends on the colors of the combined translucent panel and substrate.  
         [0023]    A radiant cooktop  30  (FIGS. 3 and 4) constructed in accordance with the present invention, which is similar in construction to the radiant cooktop  10  in FIG. 1, includes a white frame or substrate  31  which is configured to support a glass-ceramic panel or overlay  52  (FIG. 5). Specifically, a white glass-ceramic panel  52  is disposed on the white frame  31  in an area of overlap B (FIG. 6).  
         [0024]    The white frame  31  includes a backsplash  33  which is generally perpendicular to and merges with a top  34 . The top  34  is generally defined by an outer peripheral wall  35  (FIG. 4), an inner peripheral wall or inboard peripheral edge portion  36  and one or more medial peripheral walls  37  all arranged to define a generally stair-step or stepped configuration. The outer peripheral wall  35  is generally perpendicular to and merges with an outer depending side wall  41  and a first medial depending side wall  42 . The first medial depending side wall  42  is generally perpendicular to and merges with the medial peripheral wall  37  which is generally perpendicular to and merges with a second medial depending side wall  43 . The second medial depending side wall  43  is generally perpendicular to and merges with the inner peripheral wall  36 . The inner peripheral wall  36  is generally perpendicular to and merges with an inner depending side wall  44  which defines an opening  38  of the white frame  31 .  
         [0025]    The white glass-ceramic panel  52  includes an exterior perimeter edge or outboard peripheral edge portion  53  which is disposed on the white inner peripheral wall  36  in the area of overlap B (FIG. 6). The white glass-ceramic panel  52  also includes a terminal edge  54  which abuts the second medial side wall  43  of the white frame  31 .  
         [0026]    A coating  39  of material is applied to the inner peripheral wall  36  at the area of overlap B (FIG. 4). As a result, the coating  39  is sandwiched in the area of overlap B between the exterior perimeter edge  53  of the white glass-ceramic panel  52  and the inner peripheral wall  36  of the white frame  31 . In general, the coating  39  is a dark-colored material. For example, the coating  39  is a black or dark gray temperature-resistant RTV silicone adhesive, such as Pactan® 6079, which is manufactured by Heidelberger Bauchemie GmbH of Germany. Although the dark coating  39  is shown applied to the inner peripheral wall  36  at the specific area of overlap B, it can also be applied to the white glass-ceramic panel  52  before the white glass-ceramic panel  52  is placed on the inner peripheral wall  36  to cover the opening  38 . Regardless of where the dark coating  39  is applied, the amount applied generally exactly covers the area of overlap B between the white glass-ceramic panel  52  and the inner peripheral wall  36 . If the dark coating  39  covers less than the area of overlap B, a small area will still appear to have the unacceptable hue coloration. Conversely, if the dark coating  39  covers more than the area of overlap B, the dark coating  39  will be visible, which is also not acceptable. Another benefit of using the RTV silicone adhesive as the dark coating  39  is that additional fastening materials can be eliminated, since the dark coating  39  has sufficient adhesive strength to bond the white glass-ceramic panel  52  to the white frame  31 .  
         [0027]    Although the dark coating  39  is shown disposed on only the inner peripheral wall  36 , the dark coating  39  can also be applied to one or both of the second medial depending side wall  43  and the inner depending side wall  44  in order to more completely mask any reflection of the unacceptable wavelengths of visible light from these surfaces back through the terminal edge  54  and/or the area of overlap B. Similarly, the dark coating  39  can also be extended to cover the entire surface of the top  34  of the white frame  31 . For example, if the white glass-ceramic panel  52  is disposed on the medial peripheral wall  37 , the dark coating  39  would be applied to completely cover the inner depending side wall  44 , the inner peripheral wall  36 , the second medial depending wall  43 , the medial peripheral wall  37  and the first medial depending side wall  42 . Likewise, if the white glass-ceramic panel  52  is disposed on the outer peripheral wall  35 , in addition to the areas of the white frame  31  coated in the previous example, the dark coating also would be applied to the outer peripheral wall  35 . The actual area to be coated is determined by the size and shape of the translucent glass-ceramic panel that is to be placed on the top  34  of the white frame  31 .  
         [0028]    In accordance with the present invention, the frame or substrate  31  can also be configured to include multiple openings and/or a solid continuous surface in any desired shape or size. For example, when a solid continuous surface is used, the boundary of an area of overlap on the surface of the substrate that would need to be coated with the dark coating  39  is equal to the size of a perimeter of a translucent glass-ceramic panel  52  to be placed on the surface of the substrate. Alternatively, the side of the translucent glass-ceramic panel  52  that will be disposed against the substrate  31  can be completely coated with the dark coating  39 .  
         [0029]    Incoming visible light is shown by a first arrow line  61  passing through the white glass-ceramic panel  52  which is absorbed by the dark coating  39  underneath the white glass-ceramic panel  52  in the specific area of overlap B (FIG. 6). It is the absorption of this visible light by the dark coating  39  that masks the unacceptable hue coloration from being visible to the “naked” eye E. As a consequence of passing through the white glass-ceramic panel  52 , some of the wavelengths in the visible light spectrum are filtered out, and the remaining unfiltered visible light wavelengths are absorbed by the dark coating  39 . Thus, the white glass-ceramic panel  52  appears in its true light color to the “naked” eye E without any unacceptable hue coloration. The only hue that may be visible is a light grayish hue due to the dark coating  39 . However, this grayish hue is acceptable since it is generally consistent with the appearance of the rest of the white glass-ceramic panel  52 .  
         [0030]    In addition to the visible light masking properties, in the illustrated embodiment of the present invention, the RTV silicone adhesive  39  is temperature resistant and also can serve as a dampening agent between the translucent glass-ceramic panel  52  and the frame  31 .  
         [0031]    In accordance with the present invention, the selection of the specific color/shade of the dark coating  39  depends on the color of the translucent glass-ceramic panel  52  and also the color of the frame  31  upon which the translucent glass-ceramic panel  52  is disposed. In general, the color of the dark coating  39  is selected to prevent the unfiltered visible wavelengths of light from reflecting off the frame  31  and back through the translucent glass-ceramic panel  52 . The wavelengths for the visible light spectrum which are blocked/absorbed by the dark coating  36  range from approximately 340 to 760 nanometers.  
         [0032]    Although a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made in the apparatus without departing from the spirit and scope of the invention, as defined by the appended claims.