Translucent alumina filaments and tape cast methods for making
AssigneeCorning Incorporated
InventorsWeiguo Miao, Nathan Michael Zink
Life of this patent
Estimating the term…
Abstract
A translucent alumina substrates, as defined herein, are disclosed along with methods of making translucent alumina substrates via such methods as tape casting. The translucent alumina substrates have advantages over prior filaments due to their quality, including total transmittance, and surface qualities, along with the simplicity of making these materials via scalable processes, such as tape casting.
Claims16
A light bulb comprising an alumina filament, one or more LEDs in contact with the alumina filament and which radiate light partially through the alumina filament, and a phosphor coating over at least part of both the LEDs and the alumina filament, wherein the alumina filament:
- i. comprises a three-dimensional monolithic structure having two major dimensions, x and y, and a thickness, n, wherein at least one of x or y is at least 10 times larger than the thickness, with the proviso that neither x or y is greater than 100 mm and n is about 1 mm or less;
- wherein:
- a) the alumina filament has at least one unmodified surface such that the unmodified surface includes grains with an average height from about 25 nm to about 10 μm protruding therefrom, and
- b) whereby the unmodified surface facilitates attachment of the phosphor coating;
- and
- ii. has a total transmittance of at least 30% when the alumina filament has a thickness of 500 μm.
A light bulb, comprising:
- a transparent alumina filament, the transparent alumina filament having a total transmittance of at least 30% at a wavelength in the range from 300 to 800 nm;
- an LED supported by the alumina filament, wherein the LED radiates at least some light through the transparent alumina filament when the light bulb is on, and
- a phosphor coating surrounding at least part of both the LED and the alumina filament,
- wherein the alumina filament has a surface with a granular profile that includes grains with an average height from about 25 nm to about 10 μm protruding relative to recessed portions of the surface at boundaries between the grains.
Dependencies are inferred from the claim text.