1. Field of the Invention
The invention relates to the field of glass product manufacturing, and, in particular to a method of making colored glass sheets containing dark portions.
2. Description of Related Art
It is well known to use ceramic paints in the form of glass frits to coat the surface of glass sheet or at least a portion thereof with glass frits. For example, in the U.S. Pat. No. 5,328,753 “Glass Sheet Having Painted Exterior Surfaces” by T. Boaz discloses a process for painting the exterior surface of a glass sheet by applying consecutive layers of metal-containing ceramic paint and an organic paint. The coated glass sheet is then heated to a plastic set temperature, a temperature wherein the glass is capable of being permanently bent, but a temperature below which an applied stress will not cause permanent deformation, such that the ceramic paint is fused to the glass. U.S. Pat. No. 4,596,590 “Method Of Forming A Glass Sheet With A Ceramic Paint Thereon”, U.S. Pat. No. 4,684,389 “Method Of Forming A Glass Sheet With An Oil based Ceramic Paint Thereon”, U.S. Pat. No. 4,770,685 “Method Of Manufacturing Formed Glass Sheet With Paint Thereon” and U.S. Pat. No. 4,857,096 “Method Of Forming A Glass Sheet With A UV-Base Ceramic Paint”, all by P. T. Boaz all disclose a method of forming glass sheet with multi-layers of ceramic paint thereon and compositions thereof. Another example of applying ceramic paints to glass sheet can be found in U.S. Pat. No. 4,339,257 “Method Of Producing Curved And Partly Colored Glass Sheet by K. Ueda also discloses a method of forming glass sheet with glass frit coatings. Of additional interest is U.S. Pat. No. 4,837,383 “Glass Enamel” by R. Andrews, which discloses a formulation for an enamel opaque useful in providing an opaque border for both automotive and architectural glazing.
Thus it is old in the art to make ceramic or glass tiles and the like by: 1) taking two glass sheets and coating one or both facing surfaces; 2) joining them together, and fusing them together in an oven or kiln. However, while all these glass fabrication systems can produce colorful sheets they do not provide a simple way to produce a dark spot within the sheet. In the past, some sort of special coating had to be applied to the surfaces of sheets to be bonded to each other prior to fusing them together. This was a time consuming operation that had to be carefully performed.
Thus, it is a primary object of the invention to provide a ceramic panel or tile that incorporates colors as well as a dark portion.
It is another primary object of the invention to provide a ceramic panel or tile that incorporates a color wherein the panels can be completely covered with color producing frits and no additional internal coating need be applied prior to fusing the two glass panels or plates together.