Transparent or translucent inorganic material with high transmission in the 2700-3300 nm wavelength range

DETAILED DESCRIPTION It is an object of the present invention to provide cooking systems with improved energy transport from the heating element to the cookware.
The energy transport is to be improved especially in case of cookware having "poor" properties with regard to heat dissipation by buckled pan bottoms so that the usage properties are not substantially poorer than those in "good" cookware.
At the same time, the other essential characteristics of the cooking surface must be preserved.
In the visual range, the transmission must be set so that turned-on heating elements are visible even at low power, but, at full power, a person's eyes are protected from damaging radiation and glare.
The plate must absorb light to such an extent that it appears opaque in the unheated zone in incident light.
Also, the material compositions heretofore used with success are to be altered as little as possible.
In order to obtain the variability of transmission in the IR range, the combinations of coloring oxides utilized had to be expanded from what was previously known; otherwise, it would be impossible to simultaneously attain strong absorption in the visible range up to about 600 nm and variable absorption in the IR range.
Of the two coloring oxides,Cr.
sub.
2 O.
sub.
3 and V.
sub.
2 O.
sub.
5, with strong absorption up to about 600 nm in h-quartz mixed crystal-containing glass-ceramics and with very good transparency starting at about 1000 nm, Cr.
sub.
2 O.
sub.
3, for example, can be employed only in very small amounts, since it allows the upper devitrification temperature to rise greatly, and the associated glasses cannot be processed.
However, this is merely one of the many difficulties encountered in attempting to adjust the IR transmission by way of a combination of coloring oxides, wherein the adjustability is additionally restricted to a wavelength range of up to 2.
6 .
mu.
m.
It is another object of the present invention to provide inorganic materials, for example, glass-ceramics, with an increased total transmission, wherein the transmission in the near infrared (600 nm to 2