초록 ▼

A thin film tin-oxide heater (10) including an annular inner heat region (12), an annular outer heat region (14), a first silver buss bar (16), and a second silver buss bar (18). The radius (r.sub.2) between the inner and outer heat regions is selected so that the resistance per unit square and powe

A thin film tin-oxide heater (10) including an annular inner heat region (12), an annular outer heat region (14), a first silver buss bar (16), and a second silver buss bar (18). The radius (r.sub.2) between the inner and outer heat regions is selected so that the resistance per unit square and power per unit area for the inner heat region approximates the resistance per unit square and power per unit area for the outer heat region.

대표청구항 ▼

[ What is claimed is:] [1.]1. A circular resistance heating element comprisingan annular, electrically conductive, thin film outer heat region,an annular, electrically conductive, thin film inner heat region within the outer heat region,the outer and inner heat regions having thin films with the sam

[ What is claimed is:] [1.]1. A circular resistance heating element comprisingan annular, electrically conductive, thin film outer heat region,an annular, electrically conductive, thin film inner heat region within the outer heat region,the outer and inner heat regions having thin films with the same resistance per unit square within coating tolerances of the thin film inner and outer heat regions,a first buss bar separating and electrically connecting the inner and outer heat regions,a second buss bar electrically connected to and extending around the outer peripheral edge of the outer heat region and electrically connected to and extending around the inner edge of the inner heat region,whereby a voltage applied across the first and second bus bars is applied across the outer heat region and across the inner heat region, andwherein the relative widths of the inner heat region and the outer heat region are different and are selected such that the power per unit area for the inner and outer heat regions is equal.