JPH0233526A - Scorching and heating cooking device - Google Patents

Abstract

PURPOSE:To enable a stain in an optical path to be easily removed only with a cleaning of an optical incident port which is easily exposed to stain by a method wherein an optical guide passage for guiding a light reflected from a surface of food to an optical sensor is formed in a door structure. CONSTITUTION:As a food 6 is stored in a heating chamber 2 and heater members 7 and 8 are energized, temperatures of the food 6 and heating chamber 2 are increased, an illuminating lamp 9 is also turned on to radiate a light onto the food 6. A reflected light 19 reflected from the surface of the food 6 is incident from a light incident port 13 inside the door 3 into the door, reflected at a reflection mirror 15, passes through a light radiation port 14 and a light receiving window 18 and reaches to an optical sensor 17. When a predetermined scorch is produced at the surface of the food 6 and a predetermined variation is found in an intensity of a reflected light, the heating members 7 and 8 are turned off. With the above arrangement, although the light incident port 13 is exposed to atmosphere within the heating chamber, its cleaning can be easily carried out, so that it is possible to maintain a high accuracy in automatic control.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a cooking device that detects the state of browned food on the surface of food and automatically controls heating for browning. This allows for easy cleaning of dirt and highly accurate automatic control.

Conventional technology For the browning of foods, a cooking device that automatically controls heating is disclosed in Japanese Patent Publication No. 61-27661 and Japanese Patent Publication No. 61-276.
An invention as disclosed in Japanese Patent No. 62 is known.

The inventions disclosed in these publications involve irradiating visible light onto the food to be heated, and detecting changes in the intensity of reflected light from the food surface as the heating progresses, that is, as browning occurs. It is detected by a sensor and controls such as stopping heating when the degree of change reaches a predetermined value.0 Stopping heating when the reflectance of the food surface falls to a predetermined value. It may be rephrased as follows.

Problems to be Solved by the Invention When attempts are made to automatically control heating for browning using the above-mentioned conventional technology, the problem arises that as cooking is repeated, the influence of dirt on the optical sensor increases, resulting in a significant drop in detection accuracy. was there.

As a method to solve this problem, a method has already been proposed in JP-A-56-11.
There is the invention described in Japanese Patent Laid-Open No. 0824, in which a dirt burn-off device is installed in the light receiving part of the optical sensor so that the attached dirt can be burnt off as needed, and the invention disclosed in Japanese Patent Laid-Open No. 62-28
There is an invention described in Japanese Patent No. 4125 in which a shielding lid is provided in front of the light receiving section to reduce the chance of exposure to dirt.

However, each method has the problem that the dirt removal work is complicated and exaggerated, and it takes too much time and effort to achieve a completely clean state.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention (1) forms a light guide path in the door structure that guides the reflected light reflected from the food surface to the optical sensor, and connects the heating chamber and the heating chamber at one end of the light guide path. To easily remove dirt from an optical path by simply cleaning a light entrance port on the opposite side which is often exposed to dirt.

The light entrance at one end of the working light guide is constantly exposed to the atmosphere in the heating chamber, but by simply cleaning that light entrance, the optical path leading to the optical sensor can be easily cleaned.
Contributes to maintaining high precision in automatic control.

Example An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an electric oven. In this figure, 1 is the cooking device main body, and 2 is the heating chamber.

3 is a door that opens and closes the heating chamber, and 4 is a finder. The door 3 except for the finder 4 is made of a metal plate that does not allow light to pass through. 5 is a turntable, and 6 is a food item to be heated. Numerals 7 and 8 are cooking heaters such as sheathed heaters, which have the ability to brown and heat the food 6 mentioned above. Needless to say, a hot air generator may be used instead of the sheathed heater. Reference numeral 9 is a lighting lamp for illuminating the food, and the light IO generated by this lamp 9 is provided in a part of the ceiling wall 11 of the heating chamber 2. The light enters the heating chamber through the opening 12 and is irradiated onto the food 6. For this lamp 9, from the viewpoint of improving the accuracy of burnt detection, the glass surface of the illumination lamp 9 is colored from blue to green so that the proportion of light with a wavelength of 400 nm to 550 nm is increased, and the above-mentioned 400 nm to 550 nm
Light with a wavelength of n■ is selectively irradiated.

Reference numeral 13 denotes an opening for light entry, which is opened in the upper part of the door facing into the heating chamber.Although not shown, a member such as a transparent heat-resistant glass plate is used to prevent the atmosphere of the heating chamber, which is a contaminant, from entering. This is how it was done. Reference numeral 14 denotes an aperture that emits the light incident from the light entrance port 13, and is opened in a portion facing the outside portion of the heating chamber. This light emission port 14 also uses a member such as a transparent heat-resistant glass plate, similar to the above-mentioned front entrance port 13, so that contaminants such as the atmosphere of the heating chamber can enter [4. I tried to avoid it.

Reference numeral 15 denotes a reflecting mirror that reflects and guides the incident light from the light input port 13 to the light emission port 14. These light incident lines 13
．． Reflector 15. The light emitting aperture 14 forms a light guide path 16 within the door structure. Reference numeral 17 denotes a light sensor, and a light receiving part is installed on the main body side opposite to the portion where the light emitting port 14 described above is provided. This optical sensor 17 is, for example, 190~
The Gap Mil photodiode is highly sensitive to light with a wavelength of 520 nm, and is highly sensitive to light with a wavelength of 400 to 550 nm.

Reference numeral 18 denotes a light-receiving window through which the light emitted from the light emitting port 14 is transmitted to the optical sensor 17. 19 is light reflected on the food surface and directed toward the optical sensor 17. Reference numeral 20 denotes a control device that controls the supply of power to the cooking heater 7.8, lighting lamp 9, etc., and in particular automatically controls heating for browning of the food 6 based on the output signal of the optical sensor. It is something.

Now, when the food 6 is stored in the heating chamber 2 of the cooker constructed in this manner and electricity is supplied to the heating element 7.8, the temperature of the food 6 and the temperature of the heating chamber 2 rise due to the generated heat. At this time, the illumination lamp 9 is also turned on, and approximately
The food 6 is irradiated with light having a wavelength of nm to 550 ns.

When the surface of the food 6 becomes burnt over time, the reflected light 19 reflected from the surface where the burnt marks are generated enters the door from the light entrance port 13 at the top inside the door 3 and enters the door 1 (reflection #1).
15 and reaches the light emitting port 14, and then passes through the light receiving window 18 on the outside of the heating chamber and reaches the optical sensor 17. Wavelength 400nm to 550nm reaching the burnt detection optical sensor 17
The intensity of the nm light decreases as shown in FIG. 2, and the output signal of the optical sensor 17, which had been kept constant until then, begins to decrease.

A control device 2 into which the output signal of this optical sensor 17 is input.
0 stores the same output value at the initial stage of heating, compares the value being measured with the stored value, and determines when there is a predetermined change in the output, that is, when a predetermined browning is generated and the intensity of the reflected light changes. When a predetermined change occurs, the power to the heating element 7.8 is turned off.

In the explanation of this embodiment, an example has been taken up in which a flat reflecting mirror is provided in the light guide path 16 to guide the reflected light 19 to the optical sensor 17. However, by making the reflecting mirror a concave mirror, the viewing angle of the optical sensor 17 can be adjusted. It is possible and may be convenient.

It is also possible to use optical fibers instead of reflectors; in that case, if the optical fibers are flexible, the installation, which is likely to be problematic in the case of the above-mentioned reflector installations, will be freed from the need for accuracy. Ru.

Furthermore, if the light guide path is a separate part that can be attached to and detached from the door, it will motivate the user to clean the door more frequently.

In the above embodiments, the present invention was incorporated into a container body equipped with a high-frequency heating function. In this case, since a door seal structure for preventing radio wave leakage was formed on the door side, the light guide path could be housed within that structure. However, if the seal structure is provided on the heating chamber side rather than the door side, or if the door does not require a radio wave seal,
The thickness of the door may be insufficient to accommodate the light guide. In such a case, a part of the light guide path should be installed with a bulge on the heating chamber side of the door or on the foreign transmission side, although it is essential to take some creative measures.

Effects of the Invention Although the light entrance at one end of the light guide provided in the door is constantly exposed to the atmosphere in the heating chamber, cleaning of the light entrance can be done easily after washing, making it easy to clean. High precision of automatic control can be maintained and a useful cooking device can be provided.

Additionally, since the light entrance port to be cleaned is formed in the door, the safety effect cannot be overlooked, as it can be relatively safely cleaned even when the various parts of the heating chamber are still hot after cooking.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a microwave oven which is an example.
FIG. 2 is a diagram illustrating how the reflectance of reflected light changes. 2... Heating chamber, 3... Door, 6... Food, 7.8... Cooking heater 9... Illumination lamp, 13... Light entrance port, 14... Light emission port , 15・
...Reflector, 17... Light sensor, 18... Light receiving window, 20... Control device.

Claims (1)

[Claims] 1. A heating chamber (2) for storing food (6), and a cooking heater (7) for heating the food until browned.
, (8), a lighting means (9) for irradiating the food with light, a door (3) for opening and closing the heating chamber, and a light entrance opening opened in a part of the door facing into the heating chamber. (13) and the other end thereof is opened in a part facing the outside of the heating chamber to form a light emission port (14), through which reflected light (19) irradiated from the illumination means and reflected on the surface of the food is incident. a light guide path (16) formed in the door that emits light; and a light sensor (16) that receives light from the light emitting port by entering the cooking device main body (1) side opposite to the light emitting port of the light guide path. 17); and a control device (20) that controls the cooking heater based on the output signal of the optical sensor. 2. The browning cooking device according to claim 1, wherein the light guide path is formed within the door structure. 3. The browning cooking device according to claim 1, wherein the light guide path is detachable from the door.