JPH05234672A - High frequency heating device - Google Patents

Abstract

PURPOSE:To lessen the leakage of microwaves while the strength of a window is being maintained as well as to enhance the transparency of the window by allowing the holes of a microwave shielding plate forming the window of a cooking chamber to be of choke structure in a high frequency heating device which has a cooking chamber built in inside. CONSTITUTION:A cooking chamber 2 is provided in the inside of a high frequency heating device 1, and a door 3 for a heated article to be put in and out, is provided in front of the cooking chamber in such a way as to be freely opened/closed. A magnetron 4 for generating microwaves is positioned at the outside of the cooking chamber 2, and microwaves from the magnetron 4 are irradiated to the inside of the cooking chamber 2 with both a wave guide 5 and a stirrer 6 provided for the outside of the upper plate of the cooking chamber 2. A door window 7 is provided for the door 3 so that the inside of the cooking chamber 2 can be seen. In this case, the window 7 is made up of a transparent panel 8, and of a microwave shielding plate 9 furnished with a plural number of holes 10, so that the leakage of microwaves is minimized. Here, each hole is made to be of a choke structure, when microwaves have come in in the inside of each hole 10, the interference of microwaves is overwhelmed with one another by letting microwaves come in and be reflected by folded sections 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency heating device equipped with a magnetron. The high-frequency heating device also includes a combination of different heat sources such as an electric heater and a gas flame such as a toaster range, an oven range, and a gas convection range.

[0002]

2. Description of the Related Art In a high frequency heating apparatus equipped with a magnetron, a door window is provided in a door portion so that the state of the cooking chamber can be seen during cooking. The door window is composed of a transparent panel and a microwave shielding plate. Conventionally, a microwave shield plate is generally 0.5 to 0.9 mm thick and is constructed by providing a large number of circular punched small holes on the surface thereof.
This circular hole cannot be larger than 1.2 mm in diameter for the reason described later.

[0003]

The high-frequency heating device has a microwave leakage of 5 cm due to the Electrical Appliance and Material Control Law.
Must be less than 1 mw / cm ² measured at the distance. This is because the leaked microwaves are harmful to the human body. Only the microwave shielding plate blocks the leakage of microwaves from the door window, and the user can check the state of the cooking chamber during microwave irradiation through the door window. , The structure for preventing microwave leakage at the door window must be made more rigorously than other parts. Therefore, in the conventional high-frequency heating device, the diameter of the circular punched hole provided in the microwave shielding plate forming the door window cannot be 1.2 mm or more,
To increase the transparency of door windows, you have to increase the number of holes,
There was a problem that the strength of the door window was weakened.

[0004]

DISCLOSURE OF THE INVENTION The present invention proposes to make a hole of a microwave shielding plate constituting a door window a structure called a choke structure. The choke structure is a structure in which the periphery of a hole is bent outward or inward in a tubular shape.

[0005]

EXAMPLE FIG. 1 shows a front view of a high-frequency heating apparatus according to the present invention. The high frequency heating device (1) has a cooking chamber (2) inside, and a door (3) for loading and unloading the object to be heated is attached to the front face so as to be openable and closable.

The high-frequency heating device (1) has a magnetron (4) for microwave generation outside the right side of the cooking chamber (2), and a waveguide (2) is provided above the top plate of the cooking chamber (2). 5) and stirrer (6) are installed, magnetron (4)
Is applied to the inside of the cooking chamber (2) to heat the food to be cooked.

The door (3) is provided with a door window (7) so that a user can look inside the cooking chamber (2) during cooking. FIG. 2 is a partial sectional view of the door window (7). The door window (7) is composed of a transparent panel (8) and a microwave shielding plate (9). The microwave shield (9) is provided with a number of holes (10).

In the door window (7), microwaves pass through the transparent panel (8), so the microwave shielding plate (9) prevents microwave leakage from occurring at least as specified by the Electrical Appliance and Material Control Law. Must be less than or equal to the value.

Holes (10) in the microwave shielding plate (9)
Has a structure called a choke structure. In this embodiment, the microwave shield plate (9) has a thickness of 0.5 to
In the case of 0.9 mm, in order to make the diameter of the hole (10) 3.0 to 8 mm, it is achieved by setting the length of the bent portion (11) around the hole (10) to 1.2 to 2 mm. This was confirmed by actually measuring the radio wave leakage.
That is, the microwave of frequency 2450 MHz is used for the peephole (1
Even when it enters inside 0), the microwave hits the surrounding bent portion (11) and is reflected, so that the microwaves interfere with each other and cancel each other out. Is less than the specified value of.

In order to make the hole a choke structure of a desired length, assuming that the desired length is l and the diameter of the hole is d, a punching hole having a diameter of d-2l is made in advance by a press machine, and then a diameter of d is obtained. This is done by punching the center of the hole with a press machine having a punching die.

The hole (10) having the choke structure can have a larger diameter than at least a hole for punching. In the above embodiment, the Electrical Appliance and Material Control Law was given as an example, but similar regulations are also in other countries and are established as international standards.
The present invention can be applied not only to domestic products but also to export products.

[0012]

Since the present invention is configured as described above, it has the following effects.

By making the holes of the microwave shielding plate constituting the door window a choke structure, the diameter of the holes is 1.2 mm.
As described above, the transparency can be improved without changing the strength of the door window.

[Brief description of drawings]

FIG. 1 is an overall front view of a high-frequency heating device equipped with a door window according to an embodiment of the present invention.

FIG. 2 is a partial sectional view of a door window according to an embodiment of the present invention.

[Explanation of Codes] (1) High Frequency Heating Device (2) Cooking Room (3) Door (7) Door Window (8) Transparent Panel (9) Microwave Shield Plate (10) Hole (11) Bent around Hole Part

Claims (1)

[Claims] 1. A high frequency heating apparatus comprising a magnetron, wherein a hole of a microwave shielding plate forming a door window in the cooking chamber has a choke structure.