JPH0320990A - Heating cooker - Google Patents

Abstract

PURPOSE:To detect the volume change of a heated object and control heating by judging the shielding state to a light receiving section with a state detecting section. CONSTITUTION:The food 2 with a remarkable volume change has nearly the same shape as that of a container before heating, it does not interrupt the optical path between light transmitting/receiving sections when it is set on a turn table 3, the light receiving section 6 detects the light from the light transmitting section 4 after a power source is turned on, and its output signal is fed to a state detecting section 8. The detecting section 8 judges that the expansion quantity of the food 2 is insufficient and continuous heating is required based on the level of the output signal and sends a heating command signal to a controller 9. The controller 9 judges the continuation of heating based on the command signal from a panel 10 and the heating command signal from the detecting section 8 and command the continuation of heating to a magnetron circuit 11. The food 2 is expanded and interrupts the optical path. The output level of the light receiving section 6 is changed, and the power feed to the circuit 11 is stopped as a result.

Description

Detailed Description of the Invention The present invention relates to a heating cooker, and more particularly to a cooking device such as a microwave oven that can control the power source of a heating source according to the state of the object to be heated. .

In heating cooking devices, especially microwave ovens, it is not easy to identify the optimal heating state during the heating process. For this reason, various efforts have been made to incorporate information on the type and weight of the food to set the heating time and adjust the power supply. A mechanism has been proposed for this purpose.

In addition, in conventional microwave ovens, a light emitting part is installed on one wall in the heating chamber, and a light receiving part is installed on the opposite wall. A device with a mechanism that detects whether food is placed in a position that blocks the optical path and sets the distance from the heater has also been proposed. Depending on the type of food, the method of controlling the operation of the heating source using food type and weight information, as in the conventional device described above, may not necessarily achieve the objective. That is, when cooking popcorn, for example, the volume change due to heating is very noticeable, and for such foods, it is extremely preferable to use the volume change as information for cooking control.

As a method for detecting the presence of food, a light emitting part is installed on one side of the space in which the food is placed, and a light receiving part is placed on the other side. A method has been proposed to detect the presence of . However, food detection using the conventional light receiving and emitting parts is difficult.
This is provided as a means to recognize the height of the food set in the heating chamber and adjust the position of the heater, which is movable up and down, to appropriately apply radiant heating from the heater. The heating source was not controlled by detecting the cooking state, and was insufficient to achieve optimal heating.

The present invention has been made in view of the problems of the conventional devices described above, and an object of the present invention is to provide a cooking device that controls heating by detecting changes in the volume of an object to be heated.

In order to achieve the above object, the present invention includes a light emitting section on one side of the opposing wall of the heating chamber and a light receiving section on the other side, so that the light from the light emitting section can enter the light receiving section. A state detection section is installed in a positional relationship, and the output signal is input to the light receiving section.The state detection section is connected to the light receiving section to determine whether there is an object blocking the optical path between the receiving and emitting sections, and the judgment output signal of this state detection section is connected to the power source. This is input to the control circuit to control the heating cooker.

The object to be heated set in the hole heating chamber initially has a small volume, so it does not block the optical path between the receiving and emitting parts, so the signal from the emitting part is input to the receiving part and the power is turned on. Accordingly, the power supply circuit is activated and performs a heating operation. The object to be heated that has absorbed the energy gradually expands and eventually enters the optical path between the light receiving and light emitting sections, thereby preventing the signal from the light emitting section from being input to the light receiving section. The state detection section determines the light blocking state of the light receiving section and supplies a determination signal to the power supply control circuit. Based on the content of the determination signal, the power supply control circuit cuts off the power supply to the heating means immediately or after a predetermined period of time, and ends the heating cooking.

Thick” L inferior The present invention will be explained in detail using a microwave oven as an example.

In FIG. 1, a turntable 3 for setting food 2, which is an object to be heated, is provided inside a heating chamber 1. As shown in FIG. The turntable 3 is rotated by a drive mechanism installed in the space between the heating chamber l and the housing (not shown), and the food 2
Prevent uneven heating. The heating chamber l is connected to the waveguide through a waveguide.
Alternatively, a microwave radiating device such as a magnetron is directly coupled to radiate microwaves into the interior of the heating chamber 1 in response to power supply, and irradiate the food 2 placed on the turntable 3 with the microwaves.

A light emitting section 4 made of a light emitting diode is attached to one wall surface IA of the opposing walls of the heating chamber l, and light emitted from the light emitting section 4 is projected into the refrigerator through a small window 5 machined in the wall surface. Ru. A light receiving section 6 made of a phototransistor or the like is attached to the outside of the refrigerator through a small window 7 at a position facing the light emitting section 4 on the other wall surface IB of the heating chamber 1, and there is no object blocking the optical path inside the refrigerator. The light projected from the light emitting section 4 reaches the light receiving section 6 and forms one state determination signal.

Here, the mounting position of the light receiving/emitting section is determined in consideration of the surface of the dinner table 3 and the volume change of the food 2 before and after heating. In order to increase flexibility for food, the receiving and emitting parts are mounted on the wall using a mechanism that can change their position.
Correspondingly, the small windows 5 and 7 can also be shaped into long holes.

FIG. 2 is a block diagram showing a microwave oven power supply circuit whose heating operation is controlled based on the output signal of the light receiving section 6. As shown in FIG. In the figure, a state detection section 8 is connected to the output end of the light receiving section 6, and detects whether or not the optical path between the above-mentioned receiving and light emitting sections is blocked based on the output signal of the light receiving element. A state detection signal is supplied to the control section 9. A command signal for heating is input to the control unit 9 together with a heating start command instructed from the operation panel 10 , and the magnetron circuit 11
control the power supply to the The light emitting diode 4 and the phototransistor 6 are connected to the electric power Evo and emit light when the power is turned on, and the phototransistor 6 detects the output light.

Next, the operation of the microwave oven having the above configuration will be explained.

Foods that change significantly in volume, such as popcorn, have almost the same shape as the container before being heated, so when set on the turntable 3, light can be received by turning on the power without blocking the optical path between the receiving and emitting parts. In the section 6, the light emission from the light emitting section 4 is detected and an output signal P shown in FIG. 3 is given to the state detecting section 8. The state detection section 8 determines from the level of the output signal that the amount of expansion of the food is insufficient and that it is necessary to continue heating, and provides a heating command signal to the control section 9. Control unit 9
determines the continuation of heating from the command signal from the panel IO and the heating command signal from the state detection section 8, and activates the magnetron circuit 1.
1 to continue heating.

The food 2 supplied with energy expands and eventually blocks the optical path as shown in FIG. Due to the interruption of the optical path, the output signal of the light receiving section 6 changes to the level Q shown in FIG. Heating ends when commanded.

It is known that depending on the type or heating characteristics of the food 2, it is preferable to continue heating for a predetermined period even after volume expansion. The control unit can also be arranged so that the heating does not stop immediately after the optical path is interrupted, but instead continues the heating for a certain period of time depending on the food.

Although the above embodiment is constructed using a light emitting diode, a transistor, and a light emitting diode, the structure is not limited to this embodiment. It is also possible to use a semiconductor laser, photodiode, etc.

According to the present invention, by adding a simple structure, it is possible to heat and cook food groups that are subject to volumetric expansion in a manner suitable for the food, thereby reducing the burden on the operator. food can be cooked stably.

[Brief explanation of drawings]

Fig. 1 is a model diagram of a device showing an embodiment of the present invention, Fig. 2 is a circuit block diagram of the embodiment, Fig. 3 is a signal wave diagram explaining the operation of the embodiment, and Fig. 4 is the same. It is a model diagram explaining the operating state inside the heating chamber of the example. 1- heating chamber, 2- food, 3- turntable, 4- light emitting section. 6-light receiving section, 8-state detecting section 9-control section. 10-
Operation panel, 11- Magnetron circuit.

Claims (1)

[Claims] (1) A light emitting part provided on one of the opposing wall surfaces at a predetermined height from the cooking installation surface of the cooking chamber that stores the food to be cooked; a light receiving section provided at a position facing the light emitting section; a power source for driving the light emitting section; a state detecting section into which the output signal of the light receiving section is input; and a heating section into which the output signal of the state detecting section is input. 1. A heating cooker comprising: a control section for controlling power supply of a source.