JPS5832756B2 - High frequency heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of feeding power into an oven of a high-frequency heating device.

Conventionally, in microwave ovens, uneven heating occurs due to the load of food and the attenuation of internal standing waves and direct waves on the load, but as a solution to this problem, mechanical rotation and rocking movements have been developed. Various methods have been taken, such as applying the wave to a metal (radio wave reflector) provided in the cavity to convert the mode and intentionally reflect the direct wave, but the effect cannot be obtained sufficiently.

The present invention does not convert modes by conventional mechanical movement, but by an electronic method.

The present invention will be explained below according to an illustrated embodiment.

Fig. 1 is a schematic cross-sectional view showing an embodiment of the high frequency heating device of the present invention, Fig. 2 is a top view of the invention, Fig. 3 is an equivalent circuit diagram of the invention, and Fig. 4 is similar to Fig. 3. FIG. 3 is a specific configuration diagram of the equivalent circuit diagram shown in FIG.

First, the principle will be explained according to the equivalent circuit diagram shown in FIG.

Reference numeral 1 is a DC power source for bias, which is usurped by an electronic switching circuit or a mechanical female switch.

2 is a diode, P which can follow the microwave sufficiently.
It has an N junction and has low parasitic reactance.

3 is a TEM transmission line, and the distance of the diode from the short-circuited part of the transmission line is electrically set to nλ/4.

The current flowing through the TEM transmission line is ZO... TEM transmission line impedance β... phase constant e... since the diode is in an open state and its impedance is zl)0 when no voltage is applied to the diode.・Microwave power source t...Line length between the antenna and the diode When a voltage is applied to the diode, a current flows through the junction, and its impedance is outside the forward resistance, Rs is 0, and the flowing current is nλ/4. given a phase change of n=1 and λ/4n=
2 becomes λ/4.

Next, referring to FIGS. 1 and 2, reference numeral 5 is a magnetron, which oscillates and supplies radio waves to a waveguide 6, which is then passed through a knob matching device 7.
While being converted and matched to the TEM transmission line 3, the current is changed and radiated to the diode 4 as explained above.

8 is an oven, and 9 is a tray on which the object to be heated F is placed.

When multiple elements are switched sequentially or in combination, the radiation direction, maximum radiation position, and mode coupling change infinitely, making it easy to make the average power applied to the heated object uniform at each position. Become.

As described above, the present invention uses a TEM transmission line as a structure for feeding microwaves into the oven, and connects one end of the TEM transmission line to a P
By installing an N-structure semiconductor device, actively converting the radiation direction and mode, and uniformly supplying electromagnetic waves to the object to be heated, it is possible to achieve a uniform heating property variation range for heating with mechanical rotational motion. is large.

And since it is electrically controlled, the installation position can be arbitrary.

Furthermore, since it is easy to program and the time can be controlled by combination, the variation range of uniform heating can be increased.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an embodiment of the high-frequency heating device of the present invention, FIG. 2 is a top view of the present invention, FIG. 3 is an equivalent circuit diagram of the present invention, and FIG. 4 is the same as that of FIG. It is a concrete block diagram. 3... TEM transmission line, 4... PN structure semiconductor.

Claims (1)

[Claims] 1. A plurality of TEM transmission lines are provided in the microwave oven, and a PN structure semiconductor is provided at the end of the TEM transmission line, and each PN structure semiconductor is sequentially switched over time. High frequency heating device.