JPH0230411B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a cooking appliance, such as an oven or a microwave oven, equipped with a non-contact temperature detector.

Conventional Structure and Problems Recently, cooking appliances with non-contact thermometers and automatic cooking functions are being developed.

A conventional heating cooker will be explained below.

FIG. 1 shows a cross-sectional view of a conventional heating cooker, with reference numeral 1 showing a cooking chamber, 2 a food stand on which food to be cooked is placed, and 3 an infrared detector having a shutter 4 on the front. 5 indicates the infrared incident range of the infrared detector 3.

The operation of the conventional heating cooker configured as described above will be described below.

When cooking food, the food is placed on a food table 2 and the food is heated and cooked using electromagnetic waves or infrared rays. The shutter 4 is opened and closed, infrared rays from the food are detected by the infrared detector 3, and heating is automatically stopped when the desired temperature of the food is reached.

However, in the conventional configuration as described above,
It is necessary to place the food accurately in a part included in the infrared incident range 5 on the food table 2, and if the food is placed in a part not included in the infrared incident range 5, automatic cooking cannot be performed. In this case, the infrared rays incident range may be increased, but if the infrared rays incident range is increased, problems will occur as described below. That is, the infrared detector outputs a signal proportional to the incident infrared rays. Furthermore, infrared radiation is proportional to the temperature of the food and the area seen from the infrared detector. Therefore, even if the temperature is the same, if the area is different, the signal magnitude will be different. Therefore, if the infrared incident range is widened, even if the food is the same but has a different area, the temperature of the finished food will differ when automatically cooked.

Purpose of the Invention The present invention solves the above-mentioned conventional problems, and provides a heating cooker that can more accurately detect the temperature of food being heated and can automatically cook food regardless of its position. The purpose is to provide.

Structure of the Invention The present invention is a non-contact thermometer comprising two infrared detectors having different incident angles installed close to each other on a plane of the ceiling, and a shutter for controlling infrared rays incident on the detectors. This heating cooker is capable of more sophisticated automatic cooking by opening and closing the shutter and alternately operating the infrared detectors with different infrared incident angles.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows a cross-sectional view of a cooking device in an embodiment of the present invention. The same numbers are used for the same parts as in Figure 1. Reference numerals 6 and 7 indicate two infrared detectors disposed close to each other on the same plane, and the respective infrared incident ranges are indicated by 8 and 9, respectively. In this embodiment, on the food table 2, the infrared incident range 8
The hot water cup and cup that are often used in practical use are φ60.
~ φ80mm, and assuming that the placement error on the cooking table for φ250 to φ300mm is approximately ±10mm, φ10
It is sufficient if the diameter is ~50 mm, and in this example, it is set to 40 mm. Considering that the sponge cake that is commonly used in practice has a diameter of 150 to 240 mm, the infrared incident range 9 may be 120 to 200 mm, and in this embodiment, it is 200 mm. Shutter 10, 11
The structure is such that infrared rays can be incident on two infrared detectors independently.

The operation of the heating cooker of this embodiment configured as described above will be described below.

The infrared detector indicated by the infrared incident range 8 is defined as a first detector, and the infrared detector indicated by infrared incident range 9 is defined as a second detector. Place food on food table 2 and heat it. The temperature of the food being heated is detected by first and second detectors. Set the infrared incident range of the second detector sufficiently large (in the case of this example,
φ200mm), it is possible to automatically cook food without having to place the food precisely in a predetermined place on the food table.

To explain more specifically, by comparing the signal of the first detector and the signal of the second detector, the size of the food and the position where the food is placed can be estimated. I can cook. In other words, in the case of a small food item (φ40 mm or less), when placed within the infrared incident range of the first detector, the first and second detectors will receive the same amount of infrared input. , the signals will have the same magnitude. If the signal of the second detector is larger, it can be inferred that the food is placed outside the infrared incidence range of the first detector.

Next, in the case of medium-sized food, if the diameter of the food is φ _f , then 200 m > φ _f > 40 mm, even if there is some error in the placement position on the cooking table, the first detector Because it can cover the infrared incident range of
The output of the second detector is (φ _f /φ40 mm) times the output of the first detector. Therefore, by comparing the outputs of the first and second detectors, the diameter φ _f of the food can be estimated.

For foods with even larger diameters, i.e. φ _f > 200 mm,
Since the food covers both the infrared incident ranges of the first and second detectors, the output ratio of the first and second detectors is the ratio of their respective infrared incident angles, ie, 40 mm/200 mm. Therefore, in this case, the diameter of the food can be estimated to be φ200 mm or more.

As described above, according to this embodiment, by installing two infrared detectors with different infrared incident angles close to the ceiling and comparing the outputs of each detector, it is possible to detect foods with small diameters, for example. In this case, the location of the food can be estimated.

Furthermore, if the diameter of the food is medium or above, the diameter of the food can be estimated. Therefore, the surface temperature of the food can be estimated from the outputs of the first and second detectors, taking into account the diameter of the food, the position of the food, and the like. Therefore, it is possible to realize automatic cooking according to the surface temperature.

Furthermore, the present inventors have found that it is more effective to configure the infrared detector with a thermal detector such as a thermistor bolometer, a thermopile, or a surface acoustic wave infrared detector. That is, in the case of a thermal detector, a pair of elements having the same shape and characteristics are often used for the purpose of temperature compensation. Therefore, when constructing a detector based on the present invention, only a new shutter needs to be provided. In other words, there is no need to add a new detector.

Furthermore, the present inventors arranged the infrared detectors on the same flat plate, for example on the same printed circuit board,
It has been found that placing them close together is even more effective. That is, by arranging the infrared detectors close to each other on the same plane, it is possible to easily achieve thermal balance between the respective infrared detectors, so that more accurate food temperature can be detected. Furthermore, by arranging the shutters close to each other on the same plane, the same shutter can be used in common.

Effects of the Invention The heating cooker of the present invention has two infrared detectors with different incident angles installed close to each other on a plane of the ceiling,
By providing a non-contact thermometer comprising a shutter for controlling infrared rays incident on the infrared detector, the following effects can be obtained.

(1) Be able to estimate the size of food.

(2) The location of food can be estimated.

(3) The temperature of food can be detected regardless of the location of the food.

(4) Thermal equilibrium of the infrared detector can be easily achieved and accurate food temperature can be detected.

Since the above effects can be obtained, it is possible to realize a heating cooker that can perform more detailed automatic cooking.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional heating cooker, and FIG. 2 is a sectional view of a heating cooker according to an embodiment of the present invention. 1... Cooking room, 2... Food table, 3, 6, 7...
Infrared detector, 4, 10, 11...shutter,
5, 8, 9... Infrared incident range.

Claims (1)

[Scope of Claims] 1. A non-contact thermometer comprising two infrared detectors having different incident angles, which are installed close to each other on a plane of the ceiling, and a shutter that controls the infrared rays incident on the infrared detectors. A heating cooker equipped with. 2. The heating cooker according to claim 1, wherein the infrared detector is a thermal detector that also serves as a shutter.