Apparatus for heating a food item in a microwave oven having heater regions in combination with a reflective lattice structure

Claim 1

An apparatus for heating a food item in a microwave oven, comprising: a food item to be heated in a microwave oven, the food item having a surface to be heated; a food heating device having a non-edible heater in combination with predetermined regions of higher reflectance forming a lattice structure surrounding regions of the heater having less reflectance, the heater being capable of heating sufficiently to produce a positive temperature differential with respect to the surface of the food item, the regions of the lattice structure having a reflectance at the frequency of the microwave oven, the regions of the heater having a reflectance at the frequency of the microwave oven, the lattice structure regions having higher reflectance relative to the regions of the heater at the frequency of the microwave oven, the difference between the reflectance of the regions of the lattice structure and the reflectance of the regions of the heater being ten percent or greater, the regions of the heater comprising a material which heats responsive to microwave radiation and which has a transmittance at the frequency of the microwave oven greater than 0.003 percent, the device being located in close proximity to the surface of the food item so that the heater and lattice structure may cooperate to heat said surface, the heater and lattice structure being located on the same side of the good item during heating.

Claim 2

An apparatus for heating a food item in a microwave oven, comprising: a food item to be heated in a microwave oven, the food item having a surface to be heated; a food heating device having a non-edible heater in combination with predetermined regions of higher reflectance forming a lattice structure surrounding regions of the heater having less reflectance, the heater being capable of heating sufficiently to produce a positive temperature differential with respect to the surface of the food item, the regions of the lattice structure having a reflectance at the frequency of the microwave oven, the regions of the heater having a reflectance at the frequency of the microwave oven, the lattice structure regions having higher reflectance relative to the regions of the heater at the frequency of the microwave oven, the difference between the reflectance of the regions of the lattice structure and the reflectance of the regions of the heater being ten percent or greater, the regions of the heater comprising a material which heats responsive to microwave radiation and which has a transmittance at the frequency of the microwave oven greater than 0.003 percent, the device being located in close proximity to the surface of the food item so that the heater and lattice structure may cooperate to heat said surface, the heater and lattice structure being located on the same side of the good item during heating.

Claim 4

An apparatus for heating a food item in a microwave oven, comprising: a food item to be heated in a microwave oven, the food item having a surface to be heated; a food heating device having non-edible heater regions capable of heating sufficiently to produce a positive temperature differential with respect to the food item, the device having second predetermined regions forming a lattice structure, the second regions being made from material having greater than 85 percent reflectance, the second regions having a resistivity less than ten ohms per square, the heater regions having a resistivity greater than or equal to one ohm per square, and less than or equal to 10,000 ohms per square, the food heating device being operative to heat said surface of the food item when placed in close proximity thereto while being exposed to microwave radiation, the heater regions and second regions being located on the same side of the food item during heating.

Claim 5

An apparatus for heating a food item in a microwave oven, comprising: a food item to be heated in a microwave oven, the food item having a surface to be heated; a food heating device having non-edible heater regions capable of heating sufficiently to produce a positive temperature differential with respect to the food item, the device having second predetermined regions forming a lattice structure, the second regions being made from material having greater than 85 percent reflectance, the second regions having a resistivity less than ten ohms per square, the heater regions having a resistivity greater than or equal to one ohm per square, and less than or equal to 10,000 ohms per square, the food heating device being operative to heat said surface of the food item when placed in close proximity thereto while being exposed to microwave radiation, the heater regions and second regions being located on the same side of the food item during heating.

Claim 6

An apparatus for heating a food item in a microwave oven, comprising: a food item to be heated in a microwave oven, the food item having a surface to be heated; a food heating device having non-edible heater regions capable of heating sufficiently to produce a positive temperature differential with respect to the food item, the device also having second predetermined regions made from material having greater than 85 percent power reflectance, the second regions having a resistivity less than 15 ohms per square, the heater regions including dielectric material having a relative dielectric loss factor E" greater than 2.

Claim 7

An apparatus for heating a food item in a microwave oven, comprising: a food item to be heated in a microwave oven, the food item having a surface to be heated; a food heating device having non-edible heater regions capable of heating sufficiently to produce a positive temperature differential with respect to the food item, the device also having second predetermined regions made from material having greater than 85 percent power reflectance, the second regions having a resistivity less than 15 ohms per square, the heater regions including dielectric material having a relative dielectric loss factor E" greater than 2.

Claim 8

An apparatus for heating a food item in a microwave oven, comprising: a food item to be heated in a microwave oven, the food item having a surface to be heated; a food heating device having non-edible heater regions capable of heating sufficiently to produce a positive temperature differential with respect to the food item, the device also having second predetermined regions made from material having greater than 85 percent power reflectance, the second regions having a resistivity less than 15 ohms per square, the second regions being formed in a lattice structure, the heater regions including microwave magnetic absorbing material.

Claim 9

An apparatus for heating a food item in a microwave oven, comprising: a food item to be heated in a microwave oven, the food item having a surface to be heated; a food heating device having non-edible heater regions capable of heating sufficiently to produce a positive temperature differential with respect to the food item, the device also having second predetermined regions made from material having greater than 85 percent power reflectance, the second regions having a resistivity less than 15 ohms per square, the second regions being formed in a lattice structure, the heater regions including microwave magnetic absorbing material.

Claim 10

An apparatus for heating a food item in a microwave oven, comprising: a food item to be heated in a microwave oven; a planar susceptor, having a thin film of aluminum metalized on a polyester substrate, adhesively laminated to a sheet of solid bleached sulfate paperboard, the susceptor having a surface resistivity between about 1 ohm per square and about 10,000 ohms per square; a planar aluminum foil grid, having a plurality of openings in a lattice configuration, the openings being a size between about 1/32 inch and about 4.8 inches; the openings having a spacing between adjacent openings which is less than 1 inch, the grid having a microwave power reflectance more than 40 percent when the grid is measure alone; and, the grid and susceptor being located on the same side of the food item, the grid and susceptor being spaced apart less than 0.5 inch, the grid and susceptor forming a composite having a microwave power transmittance less than 50 percent when the composite is measured alone without the presence of the food item, the grid and susceptor composite being in close proximity to the food item, and effective to heat the food item when exposed to microwave radiation.

Claim 11

An apparatus for heating a food item in a microwave oven, comprising: a food item to be heated in a microwave oven; a planar susceptor, having a thin film of aluminum metalized on a polyester substrate, adhesively laminated to a sheet of solid bleached sulfate paperboard, the susceptor having a surface resistivity between about 1 ohm per square and about 10,000 ohms per square; a planar aluminum foil grid, having a plurality of openings in a lattice configuration, the openings being a size between about 1/32 inch and about 4.8 inches; the openings having a spacing between adjacent openings which is less than 1 inch, the grid having a microwave power reflectance more than 40 percent when the grid is measure alone; and, the grid and susceptor being located on the same side of the food item, the grid and susceptor being spaced apart less than 0.5 inch, the grid and susceptor forming a composite having a microwave power transmittance less than 50 percent when the composite is measured alone without the presence of the food item, the grid and susceptor composite being in close proximity to the food item, and effective to heat the food item when exposed to microwave radiation.