# US 8,772,686 B2 · Shielding system for microwave ovens and microwave oven using this shielding system

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- Number: US 8,772,686 B2
- Document ID: US8772686B2
- Status: Granted
- Kind: B2
- Application number: 12/166,368
- Filed: 2008-07-02
- Published: 2009-01-08
- Granted: 2014-07-08
- Earliest claimed: 2007-07-03
- Assignees: Whirlpool Corporation
- Applicants: Wai Hang Louie; Lai Kwork Wah; Leo Liao; Daniel Wan; Nordh Erik Ulf
- Inventors: Wai Hang Louie; Lai Kwork Wah; Leo Liao; Daniel Wan; Nordh Erik Ulf
- Web page: https://patentgrep.com/patent/US8772686B2

## CPC

- H05B 6/766: {Microwave radiation screens for windows}
- H05B 6/6414: {Aspects relating to the door of the microwave heating apparatus}
- H05B 6/6488: {combined with induction heating}
- H05B 6/76: Prevention of microwave leakage, e.g. door sealings
- Y10T 428/24058: including grain, strips, or filamentary elements in respective layers or components in angular relation
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A shielding system for microwave ovens includes a first layer of parallel grounded conductors and a second layer of parallel grounded conductors substantially perpendicular to the conductors of the first layer and, for high frequency, electrically insulated therefrom, each layer presenting a plurality of parallel metal wires connected at one end and grounded.

## Claims

### Claim 1

A shielding system for microwave ovens comprising:
a first comb-shaped layer of parallel grounded conductors, the parallel grounded conductors being connected together, by a first conductor, only at one end of the first layer; and
a second comb-shaped layer of parallel grounded conductors, the parallel grounded conductors being connected together, by a second conductor, only at one end of the second layer, wherein:
the parallel grounded conductors of the second layer are substantially perpendicular to the parallel grounded conductors of the first layer, and
the conductors of the second layer are electrically insulated from the conductors of the first layer.

### Claim 2 (depends on 1)

The shielding system according to claim 1, wherein:
each layer presents a plurality of parallel, grounded metal wires.

### Claim 3 (depends on 1)

The shielding system according to claim 1, wherein:
the conductors of each layer are placed on opposite sides of an insulating plate.

### Claim 4

A shielding system for microwave ovens comprising:
a first layer of parallel grounded conductors, the parallel grounded conductors being connected together, by a first conductor, only at one end of the first layer; and
a second layer of parallel grounded conductors, the parallel grounded conductors being connected together, by a second conductor, only at one end of the second layer, wherein:
the parallel grounded conductors of the second layer are substantially perpendicular to the parallel grounded conductors of the first layer,
the conductors of the second layer are electrically insulated from the conductors of the first layer,
the conductors of each layer are placed on opposite sides of an insulating plate, and
the conductors of each layer are built as traces of a two-side printed circuit board.

### Claim 5 (depends on 1)

The shielding system according to claim 1, wherein:
the conductors of the first layer and the conductors of the second layer are electrically insulated for high frequency.

### Claim 6

A microwave oven comprising:
a cooking cavity;
a shielding system provided at one or more walls of the cooking cavity, said shielding system including:
a first comb-shaped layer of parallel grounded conductors, the parallel grounded conductors being connected together, by a first conductor, only at one end of the first layer; and
a second comb-shaped layer of parallel grounded conductors, the parallel grounded conductors being connected together, by a second conductor, only at one end of the second layer, wherein:
the parallel grounded conductors of the second layer are substantially perpendicular to the parallel grounded conductors of the first layer, and
the conductors of the second layer are electrically insulated from the conductors of the first layer.

### Claim 7 (depends on 6)

The microwave oven according to claim 6, further comprising:
a transparent door for the cooking cavity, wherein the shielding system is provided on the transparent door of the oven.

### Claim 8 (depends on 6)

The microwave oven according to claim 6, further comprising:
an electromagnetic induction coil positioned outside the cooking cavity adjacent a bottom wall of the cooking cavity,
wherein the shielding system is provided at an aperture in the bottom wall of the cooking cavity.

### Claim 9 (depends on 6)

The microwave oven according to claim 6, wherein:
each layer presents a plurality of parallel metal wires connected only at one end and grounded.

### Claim 10 (depends on 6)

The microwave oven according to claim 6, wherein:
the conductors of each layer are placed on opposite sides of an insulating plate.

### Claim 11 (depends on 10)

The microwave oven according to claim 10, wherein:
the conductors of each layer are built as traces of a two-side printed circuit board.

### Claim 12 (depends on 10)

The microwave oven according to claim 10, wherein:
the insulating plate is transparent to electromagnetic waves.

### Claim 13 (depends on 6)

The microwave oven according to claim 6, wherein:
the conductors of the first layer and the conductors of the second layer are electrically insulated for high frequency.

### Claim 14 (depends on 3)

The shielding system according to claim 3, wherein:
the insulating plate is transparent to electromagnetic waves.