Patent Number: 06294858&
Section: claims

1. A microminiature thermionic converter comprising: a first substrate comprising a dielectric material;  a second substrate comprising material selected from the group consisting of dielectric material and semiconductor material, the second substrate having a recess therein including at least one wall and a floor boundary, and the second substrate being positioned adjacent to the first substrate so that the recess opposes the first substrate: 2. The microminiature thermionic converter of claim 1 wherein the first coating has a first work function and is selected from the group consisting of BaO, SrO, CaO, Sc.sub.2 O.sub.3 and a mixture of BaSrCaO, Sc.sub.2 O.sub.3 and metal, and any combinations thereof, and the second coating is different from the first coating and has a second work function different from the first work function. 3. The microminiature thermionic converter of claim 2 wherein the second coating is selected from the group consisting of BaO, SrO, CaO, Sc.sub.2 O.sub.3, and a mixture of BaSrCaO, Sc.sub.2 O.sub.3 and metal, and any combinations thereof. 4. The microminiature thermionic converter of claim 3 wherein the first conductor and the second conductor are electrically connected via a device consuming electrical power.