Patent ID: 7755292
Filing Date: 2010-07-13
Classification: G01J,H01K

Abstract:
1. A light source comprising: a ceramic base; a generally planar double-spiral shaped filament suspended within said ceramic base; said double-spiral shaped filament material is selected from the group consisting of tungsten, an alloy of tungsten and other incandescent filament material; a transparent lid; said ceramic base includes a reflective bottom, a ledge, and a raised perimeter having a metallic surface; said ledge includes metallic surfaces embedded therein for electrical communication with said double-spiral shaped filament; said double-spiral shaped filament comprises first and second interleaved concentric spiral portions radially converging with decreasing radius and centrally joined together in a central portion; each of said first and second spiral portions of said double-spiral shaped filament includes an end contact portion, a transition portion, an arc shaped portion, an intermediate portion and a central portion, said end contact portion having a large width, said transition portion interconnected to said end contact portion and having a transition width smaller than said end contact portion, said intermediate portion having an intermediate width, said arc-shaped portion having a width initially approximately equal to said width of said transition portion and then gradually tapering to said intermediate width of said intermediate portion, and, each of said intermediate portions terminating and centrally joined together in said central portion; a first gap defined between said first and second spiral portions of said double-spiral shaped filament and a second gap defined between said second and first spiral portions of said double-spiral shaped filament; said first spiral portion being wound in a first direction and said second spiral portion being wound in said first direction; said first and second gaps being substantially constant between said intermediate portions of said spiral portions; said first gap between said transition portion of said first spiral portion and said second spiral portion being relatively larger than said first gap between said intermediate portions of said first and second spiral portions; said second gap between said transition portion of said second spiral and said first spiral portion being relatively larger than said second gap between said intermediate portions of said second and first spiral portions; said first and second gaps near and at said central portion being relatively smaller than said gaps between said intermediate portions of said spiral portions of said double-spiral shaped filament; said end contacts of said first and second spiral portions being bonded to said metal surfaces of said ledge of said ceramic base such that said double-spiral shaped filament is suspended above said reflective base; said transparent lid being soldered to said metal surfaces of said ceramic base forming a sealed chamber within which said double-spiral shaped filament resides and is suspended therein; and, said chamber being at a desired vacuum.