JPH0147690B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooking device that has a function of controlling the cooking of a heated object by detecting a phenomenon in which the reflectance of light on the surface of the heated object changes. be.

Conventionally, in a heating cooker that heats and cooks an object stored in a heating chamber, it is difficult to determine when the object has finished cooking, either by visual inspection or by empirically setting the time on a timer. Ta. However, in reality, the desired cooking time varies depending on the amount, temperature, moisture content, composition, shape, etc. of the items to be heated, so there is a drawback that the finishing time must be constantly monitored.

As a means to solve the drawbacks of such conventional technology,
Recently, a device has been proposed that detects reflected light from food being heated and controls heating by changing the illuminance of the reflected light as the food burns. Although this device is an extremely effective method, similar to controlling heating by observing the burning process of food with the human eye, in reality it still has the following problems.

In other words, in order to heat food evenly, placing the food on a rotating table and rotating it will make the heating even. However, if the food is long and narrow, such as fish or sweet potatoes, the reflected light from the food may be The transfer table fluctuates at a constant period while it rotates, and for example, if the reflected light is detected first at the position where the maximum reflected light is detected, the detection signal will become smaller as the rotation table rotates, as if the signal amount is decreasing due to the progress of burnt. When a situation like this occurs and the range of change is large, there is a problem in that the control is performed before the burnout has progressed.

The present invention has been made in order to solve the problems of the prior art, and provides a heating cooker equipped with a mechanism for appropriately automatically controlling the heating of the heated object, and which is placed on a rotating table. To provide a heating cooker capable of obtaining a proper heating finish even when the reflected light of an object to be heated changes momentarily depending on the shape of the object to be heated.

In order to achieve this purpose, a rotatable table for placing the heated object on which the heated object is placed and rotated to uniformly heat the heated object, a heat source for cooking the heated object,
A light source that irradiates the object to be heated with visible light, a means for detecting reflected light from the object to be heated, a means for controlling heating, and a control device that detects the rotational synchronization of the rotary mounting table and synchronizes the detection timing of the reflected light with it. and the heat source is controlled when the reflected light illuminance at the same location on the object to be heated reaches a predetermined value.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a sectional view for explaining the heating cooker of the present invention. Note that in this example, a heater equipped with a high-frequency heating function is used in addition to an electric heater.
The heat source in the present invention is not limited to this type.

In FIG. 1, food 2, which is an object to be heated, is placed in a heating chamber 1 mainly made of metal on a rotating mounting table 3.
will be placed on. The rotary mounting table 3 has a low reflection surface such as black or gray, and is made of metal or ceramic. 4 is a turntable,
It is mechanically connected to a rotating shaft 5, a rotation period detection device (not shown), and a motor 6, and rotates as the motor 6 rotates, thereby rotating the rotating mounting table 3 and the food 2.

A door (not shown) is provided on the side of the heating chamber 1 and can be opened and closed. Electric heaters 7a, 7b, 7 are installed on the ceiling and bottom of the heating chamber 1.
c and 7d are provided to raise the air temperature in the heating chamber 1 and generate infrared energy to heat the food 2. In addition, as a heat source in the heating chamber 1,
For example, a high frequency energy generation source 8 and a heating chamber 1 are coupled through a waveguide 9. Further, a partition plate 10 made of a high-frequency low-loss material is provided to prevent food waste from entering the waveguide 9 through the coupling hole between the waveguide 9 and the heating chamber 1. Further, in order to irradiate the food 2 in the heating chamber 1 with visible light, a lamp 11 as a light emitting source, for example, is attached to the side wall surface 12 of the heating chamber with a support 13. lamp 1
1 is configured such that visible light is concentrated on the food 2 in the heating chamber 1 by a reflective shade 14, a hood 15, and a reflective plate 16. A part of the side wall surface 12 of the heating chamber corresponding to the lamp 11 has a light-transmitting opening 17 composed of a large number of small holes, and a transparent glass is disposed to cover this opening 17 to prevent leakage of high-temperature air. Board 18
There is. The reflective plate 16 receives visible light from the lamp 11 through a light receiving element 19 arranged near the ceiling surface of the heating chamber 1.
It has the role of preventing visible light from directly reaching the food 2 and efficiently irradiating the visible light toward the food 2.
Visible light emitted from the lamp 11 is reflected on the surface of the food 2, and this reflected light is detected by the light receiving element 19. The light receiving element 19 is, for example, a sensitivity correction filter or a photodiode with a lens, and the support 20
It is supported on the ceiling surface 21 of the heating chamber 1 by. 2
2 is a cabinet. The light receiving element 19 is arranged outside the heating chamber on a line passing approximately through the center of the heating chamber 1,
In front of the element 19, a transparent glass plate 23, which is made of a heat-resistant high-frequency resistance loss material, is provided in order to prevent heating products generated from the heated food 2 from adhering to the element 19 and to prevent leakage of high-temperature air. 24 is held on the ceiling surface 21 of the heating chamber 1 by supports 20 and 25. The ceiling surface 21 has an opening 26 made up of a large number of pores to prevent high frequency energy from leaking to the outside of the heating chamber 1 and to facilitate the passage of reflected light. The bottom surface is thermally sealed. Electric heaters 27a and 27b are provided on the surface of the glass plate 24 in close contact with the lower surface of the glass, and serve to thermally decompose and remove heated products when the glass plate 24 is significantly contaminated.

A part of the air supplied by the blower 28 passes through the duct 29 and is used for cooling the light receiving element 19, and then is discharged from the exhaust port 30 to the outside of the vessel.
On the other hand, the heated wind that cools the high frequency energy generation source 8 passes through the duct 31 and is discharged from the exhaust port 32 to the outside of the vessel. The opening 33 and the exhaust port 32 of the duct 31 are configured so that high frequency energy does not leak therefrom. The power supply device 34 includes electric heaters 7a to 7d, 27a, 27b, a motor 6, a high frequency energy generation source 8, a light receiving element 19,
The blower 28 and the stabilized power supply 35 are energized.

The control device 36 controls the power supply device 34 based on the signal from the light receiving element 19 (details of the device 36 will be described later). In the figure, 37 indicates the progression of visible light, and 38
indicates the flow of wind.

Next, a method for imparting appropriate brown marks to foods in the configuration shown in FIG. 1 will be described.

First, the door is opened, the food 2 is placed on the rotary mounting table 3 placed on the turntable 4, and the door is closed. Next, when the power supply device 34 is turned on to operate the electric heaters 7a to 7d, the lamp 11 is turned on.
Then, visible light is irradiated through the opening 17 and the transparent glass plate 18, the motor 6 is driven, and the blower 28 starts blowing air. At this time, the light receiving element 19 detects the reflected light from the food surface through the glass plate 24, the opening 26, and the glass plate 23.

The detection signal 39 in this case is, for example, when there is a long and narrow food 2 on the turntable 4 shown in FIG.
Assuming that 2b indicates a portion with a large surface area and 2b indicates a portion with a small surface area, when the turntable 4 rotates, the portion changes as shown in FIG. 3 as the food moves. In other words, the signal change characteristics shown in Fig. 3 are such that, since visible light is irradiated onto the food in one direction, the signal becomes 29a when the part 2a with a large surface area approaches the side closer to the light source, and the signal becomes 29a when the part 2b with a small surface area approaches. The detection signal is 39b when the food is located at a right angle to the light source because the intermediate part 2c between the parts 2a and 2b of the food moves further away from the light source even though its surface area is intermediate. It becomes 39c. Here, as will be described later, the rotation period is measured separately and the rotation period and the detection timing are synchronized, so one period of this signal change corresponds to one rotation of the turntable. The detection signal 39 with such a period is
As the heating time elapses, the surface of the food 2 begins to burn due to the high temperature atmosphere in the heating chamber 1 and the infrared energy from the electric heaters 7a to 7d, and as shown in FIG. gradually decreases,
Point B set in advance at heating time t,
B', B'' (reflected light illuminance signals 39a, 39b, 39c
When the signal 39a, 39b, 39c and the set values B, B', B'' reach points C, C', C'' where they intersect, the signals 39a, 39b, 39c and the set values B, B', B'' intersect.
Points C, C', and C'' are the end points of the tanning, at which point the controller 36 sends a signal to the power supply 34.
The power supply device 34 receives this signal and turns on the electric heater 7a.
7d and the lamp 11 are stopped.
This means that the browning and cooking operation for food 2 has been completed. However, in reality, the dark eye detection signal 39a
It is not necessary to extract all of 39c, for example, it is sufficient to detect only 39a, which always transmits the maximum signal amount.In order to perform more accurate detection, after detecting the maximum value of the detection signal at the initial stage of heating, ,
From now on, it is preferable to detect detection signals from the same region in synchronization with the rotation of the rotary mounting table and to track changes therein.

The control device 36 according to the present invention is constructed as shown in the block diagram of FIG. In the figure, 40 is a microcomputer, 41 is a comparator, and 42 is a D/A.
43 is a code conversion circuit, 43 is a darkening adjustment section, 44 is an amplifier circuit, and 45 is a light receiving element.

When the power supply device is operated to energize the electric heaters 7a to 7d and the lamp 11 in FIG.
The light receiving element 5 receives reflected light from the food, and optical power is obtained as a detection signal. This detection signal is current-voltage converted and amplified by the amplifier circuit 44. The converted signal V _I is sent to the darkening adjustment section 43 and the comparator 41.
Sent. The dark eye adjustment section 43 shifts the dark eye detection signal to a level desired by the user and outputs the dark eye detection signal to the comparator 41.
Outputs signal V _H to . On the other hand, the microcomputer 40 sends the code signals V _I and V _H to a code signal D/A code conversion circuit 42 to read them, and sends the output signal V _DA to a comparator 41 . Comparator 41 is voltage
Compare V _I , V _H and V _DA , read V _I , V _H , and find the peak value of voltage V _I (for example, point A in Figure 4, 39a).
A point B, which is a reference value for heating completion, is created by calculation from this peak value, and a signal is sent to the power supply device 34 when the voltage at this point B and V _H are compared and the results are equal. Then, a control element (not shown) is operated to terminate the heating.

Note that the detection signal of the light receiving element 45 is read by reading the maximum value on the rotating mounting table at the start of heating.
Thereafter, the rotation speed of the motor 6 may be detected by the clock signal of the microcomputer 40, and the detection signal may be taken out only once during one rotation of the rotary mounting table 3.

As described above, the present invention heats food while rotating it on a rotating mounting table, and controls the heating by signal processing the process of changing reflected light from the food surface due to heating. The maximum or minimum value of the change in the reflected light of the food during one rotation is determined, and the reflected light is always detected when the food reaches that part, so there is no effect of illuminance fluctuations during rotation. It is possible to obtain a heating cooker that is easy to use and has excellent economic efficiency because accurate cooking results without failure can always be obtained.

Although the heating mode in the present invention has been described for browning, it can also be used for other cooking methods such as defrosting and fermentation. Furthermore, in addition to monitoring the maximum value and minimum value as a detection signal, the present invention is also effective when an average value, an integral value, or other conversion is performed. Further, a stepping motor is used as a motor to detect the rotation period of the rotary mounting table. Alternatively, it may be measured by attaching a lever to the rotating shaft and pushing a spring switch, or by using an electromagnetic pickup.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the heating cooker of the present invention, FIG. 2 is a plan view showing the state in which the food is placed, and FIGS. 3 and 4 are time and signal signals of the control device 36. FIG. 5 is a block diagram of the control device 36, which is a characteristic diagram showing the relationship with the amount. DESCRIPTION OF SYMBOLS 1...Heating chamber, 2...Food, 3...Rotating table, 4...Turntable, 7a-d...Electric heater, 11...Lamp, 19, 45...Light receiving element, 34...Power supply device , 36...control device, 39
...Detection signal, 40...Microcomputer.

Claims (1)

[Claims] 1 A rotating mounting table that places the heated object in the heating chamber, a heat source that heats the mounted heated object, a light source that irradiates the heated object with visible light, and detects the reflected light from the heated object. The rotating object is heated by a heat source, and the object is heated by detecting a change in reflected light from the object that occurs as the object is heated. 1. A heating cooking device that measures the same part of an object to be heated, characterized in that the heating cooking device is provided with a control device that detects the rotation period of the rotary mounting table and synchronizes the detection timing of reflected light with it, and measures the same part of the object to be heated.