Window with selectively writable image(s) and method of making same
Certain embodiments of this invention relates to a writable window (e.g., IG window unit), where images (e.g., advertisements, logos, designs, pictures and/or words) can be selectively written into the window and are designed to be viewed by humans and/or animals. A substrate (e.g., glass substrate) supports a solar coating such as a low emissivity (low-E) coating which may include at least one infrared (IR) reflecting layer of or including silver that is located on and directly contacting a contact/seed layer of or including a material such as zinc oxide and/or zinc stannate. A radiation source (e.g., laser(s) and/or lamp(s)) may be used to selectively expose certain areas of the coating to radiation (e.g., UV radiation). The exposed area(s) of the coating, after being exposed and heated, have different optical characteristic(s) (e.g., higher visible transmission) than the area(s) of the coating not exposed to the radiation, so that following the laser exposure the exposed area(s) form an image(s) designed to be viewed by humans and/or animals.
1. A method of making a coated article, the method comprising:
having a coated article including a low-E coating supported by a glass substrate, the low-E coating having sheet resistance (R s ) of no greater than 10 ohms/square, wherein the low-E coating is supported by the glass substrate, and wherein the low-E coating comprises at least one layer comprising silver that is located over and directly contacting a layer comprising metal oxide configured to absorb ultraviolet (UV) radiation so that an image viewable by a human eye can be formed in the low-E coating;
directing ultraviolet (UV) radiation from 300-380 nm toward the low-E coating and exposing only part of the low-E coating to UV radiation in order to form the image in the coating that can be seen by a human eye, wherein the layer comprising the metal oxide has a bandgap of from 3.15 to 3.4 eV so as to absorb selective UV radiation directed at the low-E coating and in turn heat up the layer comprising the silver in areas exposed to the UV radiation and cause the layer comprising silver to become more dense and more conductive in areas exposed to the UV radiation so that the areas exposed to the UV radiation are more transparent to visible light than other areas not exposed to the UV radiation thereby resulting in the image defined in the coated article that is viewable by a human eye.
2. The method of claim 1 , wherein the image comprises a logo.
3. The method of claim 1 , wherein the image comprises at least one word.
4. The method of claim 1 , wherein the layer comprising the metal oxide comprises zinc oxide.
5. The method of claim 1 , wherein the layer comprising the metal oxide comprises zinc stannate.
6. The method of claim 1 , wherein the layer comprising the silver has a higher visible transmission and/or reduced visible reflectance in the areas exposed to the UV radiation compared to the other areas of the coating not exposed to the UV radiation so that a shape of the image is substantially defined by the areas exposed to the UV radiation.
7. The method of claim 1 , further comprising, after said exposing, coupling the substrate with the coating thereon to another substrate in making an insulating glass (IG) window unit.
8. The method of claim 1 , wherein said UV radiation is directed toward the coating from at least one source of UV radiation.
9. The method of claim 8 , wherein the source comprises a UV emitting lamp.
10. The method of claim 8 , further comprising providing a mask between the coating and the source of UV radiation so that opening(s) defined in the mask determine which part of the coating is exposed to UV radiation from the source.
11. The method of claim 8 , wherein the source comprises a UV emitting laser.
12. The method of claim 8 , wherein the radiation emitted from the source consists essentially of UV radiation.
13. The method of claim 8 , further comprising a mask between the low-E coating and the at least one source.