Ellipsoidal reflector lamp

Abstract

A blown glass reflector lamp having an ellipsoidal reflector and a clear or lightly frosted face is disclosed.

What I claim as new and desire to secure by Letters Patent of the U.S. is: 
     
       1. An ellipsoidal reflector lamp characterized by low brightness and high illumination comprising: .Iadd.a filament, .Iaddend.   a blown glass envelope having an ellipsoidal, .[.specular.]. .Iadd.reflector .Iaddend.surface and a translucent face, wherein .Iadd.the major axis of said ellipsoidal envelope approximately intersects said filament and .Iaddend.the minor diameter of the ellipsoid defines the approximate boundary between said surface and said translucent face, .Iadd.wherein said face includes a curved portion so shaped that direct light from said filament is incident approximately normal thereto, and wherein said face includes a conical section which joins said curved portion to said ellipsoidal surface approximately at the minor diameter thereof, said conical portion forming an angle with the minor diameter at least approximately conforming to the path of the last ray reflected near the minor diameter .Iaddend.said ellipsoid has an eccentricity of from 0.66 to 0.88 inclusive, said face is .Iadd.outwardly .Iaddend.positioned no further .[.that.]. .Iadd.than .Iaddend.1/2 d from the intersection of the axes of the ellipsoid, where d is the distance from said intersection to a focus of the ellipsoid, and wherein direct and reflected light are produced within approximately equal solid angles.  .[.2. The ellipsoidal reflector as set forth in claim 1 and futher comprising a filament   
     
     
        intersecting the focus within said envelope..]. 3. The ellipsoidal reflector lamp as set forth in claim .[.2.]. .Iadd.1 .Iaddend.wherein said 
     
     
        face has a light frost. 4. The ellipsoidal reflector lamp as set forth in claim 3 wherein said envelope includes a neck portion having a heat shield positioned therein.  .[.5. The ellipsoidal reflector lamp as set forth in claim 4 wherein said face comprises a section of a spherical surface 
     
     
        joined to said minor diameter by the frustum of a cone..]. 6. The ellipsoidal reflector lamp as set forth in claim .[.5.]. .Iadd.4 .Iaddend.wherein said ellipsoid has an eccentricity of 0.78. .Iadd. 7. The ellipsoidal reflector lamp as set forth in claim 1 wherein said envelope includes a neck portion having a heat shield position therein. .Iaddend..Iadd. 8. The ellipsoidal reflector lamp as set forth in claim 7 wherein said ellipsoid has an eccentricity of 0.78. .Iaddend. .Iadd. 9. The ellipsoidal reflector lamp as set forth in claim 8 wherein said face has a light frost. .Iaddend. .Iadd. 10. The ellipsoidal reflector lamp as set forth in claim 1 wherein said ellipsoid has an eccentricity of 0.78. .Iaddend. .Iadd. 11. The ellipsoidal reflector lamp as set forth in claim 10 wherein said envelope includes a neck portion having a heat shield positioned therein. .Iaddend..Iadd. 12. The ellipsoidal reflector lamp as set forth in claim 11 wherein said face has a light frost. .Iaddend..Iadd. 13. The ellipsoidal reflector lamp of claims 1, 3, 9 or 10 wherein said filament approximately intersects the focus of said envelope. .Iaddend.