JPS6035423A - High frequency heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention Invention C1: A control circuit that uses a microcomputer (hereinafter referred to as a microcomputer) to control the high-frequency output of a high-frequency heating device, food temperature, cooking time, etc. breaks down due to static electricity charged on the human body. This is to prevent ML operations from occurring.

In recent years, microcomputers have been used in the control circuits of high-frequency heating devices, but microcomputers have the drawback of being extremely susceptible to static electricity. If static electricity charged on the human body is discharged to the knobs, panel surface, or circuit parts inside the panel, the microcomputer may malfunction or be destroyed, and the display tube may display incorrect information in devices equipped with a display tube. In this case, the device itself may operate on its own, that is, automatically oscillate.

The present invention eliminates the above-mentioned drawbacks with a simple structure, and one embodiment of the present invention will be described below with reference to the drawings.

1 includes the main body of the high-frequency heating device, a door provided in the front opening of the 2-key heating chamber (not shown) that can be opened and closed freely, and a 3-key keyboard 4.
The main body of the operation panel is generally made of plastic such as ABS resin or modified PPO (polyferrylene oxide). 5. The decorative part is made of aluminum or iron plate. 6 is a reinforcing plate on the back side of the keyboard 4. It is the metal chassis that fixes the operation panel 3. Decorative pile 5 and chassis 7 (1
An elastic metal body such as a stainless steel plate spring is electrically connected by 1°.

The structure of the keyboard 4 has a decorative film on the surface (polyester film) underneath 9! The sheet 10, the insulating spacer 11, and the resin substrate 12 are stacked in this order and fixed with adhesive. The different polarity electrodes 13.14 of the resin substrate 12 are printed under one key, and this different polarity electrode 13.14 is printed.
Insulating sheet l facing the.

An electrode 15 made of a conductive material such as carbon paste is printed on the top. Key range of insulating spacer 11 (d hole is drilled, and when the key part is pressed from the front of the device, electrodes 13, 14 and 15 come into contact and become an input signal to the microcontroller. 016 (7; l: insulation) At the lead-out portion of each electrode printed on the board 12, 17 is a connection line to the control circuit, and soldering is not required (when operating the keyboard 4,
When you bring your finger close to the keyboard 4 to press the key frame printed 6 on the front decorative film 9, in the conventional case,
If the keyboard 4 and the decorative panel 6 are not in contact and there is a space, if there is a plastic part of the operation panel main body 3 between the decorative panel 6 and the keyboard 4, or if there is no decorative panel 5 (f: 'rThe static electricity charged on the human body was transmitted through space and along the surface of the keyboard 4, and was discharged onto the conductive parts printed on the insulating substrate 12. In particular, if the electrode lead-out part 1 was covered with the insulating sheet 10, Due to its strong structure, this part was almost defenseless against static electricity.

On the other hand, as in the present invention, the decorative panel 5 and the keyboard 4
By touching the entire circumference of the electrode, including the vicinity of the lead-out part, the static electricity charged on the human body is always discharged toward the decorative panel 5 made of metal material t1, and is grounded to the chassis 7 through the leaf spring 8. Ru. Of course, since the ground is connected to the high frequency heating device, static electricity is absorbed by the ground, and the negative effect on the control circuit including the microcomputer is removed, thereby preventing malfunctions and destruction of the microcomputer.

To explain the malfunction using the circuit diagram in Figure 4, in actual use, when the door is closed, SWl, 18 and 19W2
, 19 is closed, select the high frequency output of the keyboard 4, set the heating time, and press "Start", the signal from the keyboard 4 enters the microcomputer 20, and further, the signal from the microcomputer 20 operates 1-21. The contact 22 closes and current flows through the high-voltage power supply circuit, causing the JT1 magnetron 24 to radiate the 7111 frequency and begin heating.

However, if the microcomputer 2o malfunctions due to static electricity and sends out a signal to activate the relay 21, it will cause one oscillation to occur even if you do not press "Wataru Start" on the keyboard 4, and as a result, This may lead to abnormal heating or a fire.

For reference, the amount of static electricity that accumulates on the human body depends on weather conditions, grounding conditions for the human body, type of clothing, etc.

Although there is a difference, a high voltage of 10-15KV has been confirmed.

As explained in Section V) below, a microcomputer-based high-frequency heating device (ts-C1) was used.
This high-frequency heating device protects the control circuit, including the microcomputer, from static electricity that accumulates on the human body, preventing equipment malfunction, destruction of the microcomputer, and fires caused by automatic oscillation, thereby increasing safety. Can be provided.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view of a high-frequency heating device showing an embodiment of the present invention, Fig. 2 is a sectional view showing the main part of the keyboard and its mounting structure, Fig. 3 is a detailed view of the keyboard and the mounting part, and Fig. 3 is a detailed view of the keyboard and the mounting part. 4
The figure is a circuit diagram of the same high-frequency heating device. 4... Keyboard, 5... Decorative panel, γ... Old chassis, 8... Leaf spring, 9... Decorative film,
10... Insulation sheet. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 4

Claims (2)

[Claims] (1) Built-in electronic circuit using a microcomputer to control high frequency output, food temperature, cooking time, etc.
A keyboard is used to input input to the electronic circuit, and a conductive material is arranged so as to touch a part of the entire circumference of the surface of the keyboard, and this conductive material is electrically connected to the main body chassis. A high frequency heating device characterized by being connected to. (2) The high-frequency heating device according to claim 1, wherein the front decorative plate of the operating panel is made of the conductive material.