Glass ceramic cooktop with infrared sensor

A cooktop, comprising:

• a glass ceramic cooking plate with at least one cooking zone;
• at least one heater arranged below the glass ceramic cooking plate in a region of the cooking zone;
• at least one infrared sensor having a sensing area arranged so as to face the cooking zone through the glass ceramic cooking plate;
• electronics connected to the at least one infrared sensor, the electronics being configured to control a power output of the at least one heater based on an output signal of the at least one infrared sensor, and
• wherein the glass ceramic cooking plate is made of a lithium aluminosilicate glass ceramic containing a composition (in percent by weight) of:
• Al2O3
• 18-23,
• Li2O
• 2.5-4.2,
• SiO2
• 60-69,
• ZnO
• 0-2,
• Na2O + K2O
• 0.2-1.5,
• MgO
• 0-1.5,
• CaO + SrO + BaO
• 0-4,
• B2O3
• 0-2,
• TiO2
• 2.3-4.5,
• ZrO2
• 0.5-2,
• P2O5
• 0-3,
• SnO2
• 0-<0.6,
• Sb2O3
• 0-1.5,
• As2O3
• 0-1.5,
• TiO2 + ZrO2 + SnO2
• 3.8-6,
• preferably V2O5
• 0.01-0.08,
• Fe2O3
• 0.008-0.3,
• wherein the glass ceramic cooking plate has a gradient layer at or towards a surface thereof and an underlying core,
• wherein the glass ceramic cooking plate has keatite mixed crystals as a predominant crystal phase in the core and high-quartz mixed crystals as a predominant crystal phase in the gradient layer, and
• wherein the keatite mixed crystals have a crystal phase content that exceeds 50% a total crystal phase content of the high-quartz mixed crystals and the keatite mixed crystals in a depth of 10 μm or more.