Oven window including a thermally activated, light scattering device

#View windows of various sizes and having various structures have long been used in oven doors. In order to meet applicable safety standards for allowable exterior temperatures of said view windows, however, they have typically been small in size, deeply tinted, or otherwise treated so that the view into the cooking chamber is very limited, thus creating a periodic need to open the oven door to check the progress of the item or items that are being cooked. Each time the oven door is opened, the interior temperature of the cooking chamber decreases below the desired cooking temperature, and additional energy is consumed in returning the temperature to such desired temperature. Additionally, the hot cooking chamber can pose a safety risk to small children or others who are not aware of the risk of being burned when the oven door is open.

#Accordingly, it would be advantageous to have an oven view window which would meet applicable safety standards, but would allow a substantial size view window being essentially transparent to enable the user to have a clear and expansive view of the items of food being cooked so that it is unnecessary to open the oven door to check the progress of such items.

#The present invention relates to a view window in an oven, the view window comprising a glass substrate having two major surfaces and a thermally activated, light scattering coating disposed on at least one of the major surfaces. More particularly, the glass substrate carries a normally translucent-to-opaque coating which upon exposure to heat becomes essentially transparent.

#The FIGURE is a somewhat schematic side sectional view of an oven (10) which incorporates the invention.

#In an oven (10), cooking chamber (12) is heated by one or more heating sources, such as that shown schematically at (22), in the conventional manner. Such heat energy is transferred throughout the cooking chamber, including to optional glass substrates, (16) and to glass substrate (14), which comprise in various embodiments oven view window (24). Suitable infrared reflective coatings (20) may be provided on one or both surfaces of optional substrates (16), thus reflecting some portion of the heat energy from heating source (22) back into cooking chamber (12). The glass substrate (14) or optional glass substrates (16) carry a suitable thermally activated light scattering coating (18) (shown only on substrate (14)) on at least one of two opposed parallel surfaces. Upon exposure to sufficient heat energy from heating source (22) such that when the surface carrying the thermally activated light scattering coating (18) reaches a predetermined activation temperature, it will change in appearance from translucent-to-opaque to essentially transparent.

#The substrate (14) and optional substrates (16) each have first and second major surfaces in opposed relationship, and are in a spaced apart and mutually parallel relationship to one another.

#Further, a frame (26) supports the substrate (14) and optional additional glass substrates (16) in a spaced apart and mutually parallel relationship. The frame (26) is attached to the oven door in a predetermined location.