JPS645433B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating device such as a so-called microwave oven, and its purpose is to improve the strength of the operation panel section and digital display section, improve resistance to static electricity noise, and improve the strength of the operation panel and digital display section. It is an object of the present invention to provide a high-frequency heating device that is safe and of high quality by reducing unnecessary radiation that occurs, and to provide a high-frequency heating device that is highly productive by simplifying the structure.

Conventionally, this type of high-frequency heating device has a digital display section consisting of a display tube and a translucent or transparent plate (smoke plate) made of resin or glass covering the display tube in the operation panel section, and a microcomputer for inputting instruction signals. The smoke plate and the keyboard were fixed by separate metal fixing plates. This resulted in a complicated structure and low productivity. Moreover, since the entire surface of the operation panel is not covered with metal, the structure cannot prevent unnecessary radiation generated from inside the device, and discharge sparks due to static electricity from the gaps between each metal can affect the electronic components inside the operation panel. However, it had low resistance to static electricity noise. Additionally, since the structure did not hold down the entire surface of the smoke plate, there was a problem in terms of the strength of the smoke plate.

A conventional example will be specifically described below.

Figure 6 shows a conventional example of an operation panel, with display tube 2
The smoke plate 25 covering the frame 1 is attached with one smoke plate holding plate 27 provided on each side of the smoke plate 25 using screws, and the smoke plate holding plate 27 and the operation panel frame 2 are attached.
The smoke board was held in place by sandwiching it between the two. The keyboard 13 was held down by a metal back plate 26 and screws, and was sandwiched between the back plate 26 and the operation panel frame 28 to fix the keyboard. For this reason, the smoke plate is held down only on both sides, so if you press the center, it will become sticky and its strength will be weak, and bosses are required on both sides of the smoke plate to tighten the smoke plate holding plates with screws, so the width of the smoke plate 25 will be reduced. Only narrow objects can be fixed. Because it does not cover the entire operation panel frame, static electricity can discharge from the gap into the internal electronic circuits, leading to microcontroller malfunctions. Further, unnecessary radiation from the high frequency oscillator converted inside the high frequency oscillator mentioned above escapes from the device through the gap and has an effect on other wireless products.

The present invention solves the above-mentioned conventional drawbacks, and consists of a single metal plate (back plate) that covers the entire inside of the operation panel, and a smoke plate and a keyboard are sandwiched between the back plate and the operation panel frame. The configuration is
The back plate has the effects of reducing unnecessary radiation, improving electrostatic noise resistance, and reinforcing the smoke plate.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

1 and 2 are diagrams showing the configuration of a high-frequency heating device, in which a high-frequency oscillator 1 that oscillates microwaves of 2450 AHZ is coupled to a metal waveguide 2 and an antenna 3. The high frequency wave emitted from the high frequency oscillator 1 into the waveguide 2 propagates inside the waveguide 2 and is further radiated into the heating chamber 4 . The high frequency waves radiated into the heating chamber 4 are absorbed by the food 5 placed in the heating chamber 4, and dielectrically heat the food 5 from inside the food 5. Furthermore, the high frequency oscillator 1 is self-heated due to internal loss, and is constantly cooled by the blower fan 6 during oscillation to prevent failure. A door 7 that can be opened and closed is provided on the front side of the heating chamber 4, and an electrical component room 8 is provided on the side surface of the heating chamber 4. , a high voltage capacitor 10 is located. An operation panel 11 is constructed on the front side of the electrical component room 8, and includes a digital display section 12, a keyboard 13, and the like.

Fig. 3 shows the control circuit of the high frequency heating device, and one end of the power plug 14 is used to prevent short circuits and ground faults of the electrical components that make up the high frequency heating device, as well as to prevent excessive leakage of microwaves during welding of interlocks, which will be described later. Therefore, the fuse 15 is connected to the fuse 15 which is blown by the operation of the shot switch 18. Furthermore fuse 1
5 is connected to the primary winding of the high voltage transformer 9 via two interlock switches 16 and a relay 17 whose contacts open and close as the door 7 opens and closes.
Further, the relay 17 is turned on and off in response to a heating start signal and a heating completion signal inputted to a microcomputer (hereinafter abbreviated as microcomputer) 19 through the keyboard 13. Connected to both ends of the primary winding of the high-voltage transformer 9 are a short switch 18 that disables the entire circuit when the blow fan 6 and the aforementioned interlock 16 are welded, and a lamp 20 that illuminates the inside of the heating chamber 4. ing. The other terminal of the power plug 14 is connected to the primary winding of the high voltage transformer 9. In order to indicate the contents of the command inputted to the microcomputer 19 by the keyboard 13,
In addition, to show the clock display, the display tube 2 is connected to the microcomputer 19.
1 is connected. The AC power applied to the high-voltage transformer 9 is stepped up by the high-voltage transformer 9 to become high-voltage power, and the high-voltage power is converted into high-voltage DC power that is voltage-doubled and rectified by a voltage-double rectifier circuit composed of a high-voltage capacitor 10 and a high-voltage diode 22. be done. The high-voltage DC power is supplied to the high-frequency oscillator 1 via a high-voltage switch 23 that opens and closes at certain intervals to vary the amount of high-frequency output. The opening and closing of this high voltage switch 23 is controlled according to the output mode input to the microcomputer 19 via the keyboard 13. The high-voltage DC power supplied to the high-frequency oscillator 1 is converted into high-frequency power inside the high-frequency oscillator 1 and radiated from the antenna 3. Thereafter, the high frequency heats the food 5 through the process described above.

Further, the high voltage transformer 9 is provided with a heater winding 24, and the heater winding 24 is connected to the heater of the high frequency oscillator 1 by a lead wire to heat the heater. As mentioned above, the high frequency wave converted inside the high frequency oscillator 1 is radiated from the antenna 3, but at this time, a part of the high frequency wave is propagated from the heater to the lead wire and is radiated from the lead wire as unnecessary radiation.

In addition, when the device is used by a person, the operation panel 1
1. Especially when touching the area around the keyboard, if noise enters the microcomputer 19 through the keyboard 13 due to static electricity in the human body, the microcomputer 19 may malfunction or the display tube 21 may display an incorrect image. Furthermore, if a spark occurs directly in the electronic circuit, it may lead to the destruction of the microcomputer 19.

FIG. 4 shows the operation panel of the present invention, in which the smoke plate 25' and the keyboard 13 are held down by a back plate 29 made of a single piece of metal and fixed with screws. The smoke plate 25' and the keyboard 13 are fixed by sandwiching the smoke plate 25' and the keyboard 13 between them. Further, since the outer shape of the smoke plate 25' is larger than the square hole 29-1 of the back plate, the four sides of the smoke plate 25' are held down by the back plate, and the strength can also be improved.

Since the back plate 29 is grounded to the main body via the shorting plate 30, if static electricity is supplied from the human body during use, all of it will be discharged to the back plate 29 and will not affect the electronic components inside the operation panel. Further, unnecessary radiation from the above-mentioned high frequency oscillator 1 can be prevented from escaping outside the apparatus by the back plate. Moreover, there is no need to make a boss next to the smoke plate 25' whose edges are bent for reinforcement around the back plate 29 and fix the smoke plate 25'. , and fixed the back plate 29. For this reason, smoke plate 2
It is also possible to configure the width of 5' to be wider.

FIG. 5 shows a keyboard 13 according to another embodiment of the present invention.
is small compared to the operation panel frame 28, and the above-mentioned unnecessary radiation is removed by combining the metal display panel 31 and the back plate 29, and the operation panel 11
This is prevented by covering the entire front surface with metal.
The display panel 31 is fixed to the operation panel frame 28 from the outside by inserting a claw 31-1 provided on the display panel 31 into a rectangular through hole 28-1 provided around the operation panel frame 28 and folding it. . Further, as described above, since the small through hole 28-1 is provided in the operation panel frame 28, the through hole 28 is used to prevent static electricity from the human body from sparking on the electronic components inside the operation panel 11 through the through hole 28-1.
A flange 29-2 is attached to the back plate 29 at a portion indicated by -1 so as to cover the through hole 28-1, so that static electricity is discharged to the back plate 29.

Moreover, by configuring as described above, the keyboard 13 and the smoke plate 2 can be connected to each other using a single metal plate.
5' can be fixed, and a high-frequency heating device with high productivity can be provided.

As described above, according to the present invention, the following effects can be obtained.

(1) A safe high-frequency heating device with improved strength of the digital display section can be provided.

(2) It is possible to provide a high-frequency heating device that is free from failure due to static electricity noise. In particular, since the grounded metal back plate covers almost the entire back surface of the operation panel, the effect is extremely high.

(3) Unnecessary radiation emitted from inside the device can be prevented from exiting the device, and it is possible to provide a high-frequency heating device with less influence of noise on other wireless devices.

(4) Since the smoke plate and the keyboard can be fixed in one piece, it is possible to provide a high-frequency heating device with high productivity.

(5) It becomes possible to attach a wide smoke plate, and it is possible to provide a high-frequency heating device with an improved design.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of a high-frequency heating device that is an embodiment of the present invention, and FIG. 2 is a front sectional view of the same device.
3 is a control circuit diagram of the same device, FIG. 4 is an exploded perspective view of the operation panel of the same device, FIG. 5 is an exploded perspective view of an operation panel that is another embodiment of the present invention, and FIG. 6 is a conventional FIG. 3 is an exploded perspective view of the operation panel of FIG. 1... High frequency oscillator, 4... Heating chamber, 8... Electrical parts room, 11... Operation panel, 13... Keyboard, 19... Microcomputer, 25, 25'... Smoke plate, 26, 29... Back Board, 28...Operation panel frame, 30...Short circuit board, 31...Display panel.

Claims (1)

[Scope of Claims] 1. An operation panel section having an operation panel frame, a translucent or transparent smoke plate made of resin or glass that covers a display tube of the operation panel section, and an instruction signal to a control circuit including a microcomputer. a keyboard for inputting information, and a metal back plate that fixes the smoke plate and the keyboard and covers substantially the entire rear surface of the operation panel, and the smoke plate and the keyboard are connected to the back plate. A high-frequency heating device, which is fixed by being inserted into an operation panel frame, and the back plate is grounded. 2. The high-frequency heating device according to claim 1, wherein the smoke plate is fixed using the elasticity of the back plate.