JPS61147026A - Cooker with infrared radiation sensor - Google Patents

Abstract

PURPOSE:To shorten operation time of chopper, ensure reliability and reduce cost by performing temperature detecting using infrared radiation sensor periodically at cooking time. CONSTITUTION:Food stuff 6 is dielectrically heated by supplied high frequency radio wave into a heating room. At that time microcomputer 20 emits chopper drive signal to a chopper drive circuit 8 and the signal has a periodic time to which includes operation time ta and idle time tb. Chopper performs ON-OFF operation for a time ta every constant time to and the ON-OFF operation emits intermittent incident light to infrared radiation sensor 5. Temperature detecting is performed for foodstuff 6 every time to. As temperature detecting is periodically performed at cooking time, it is expected to reduce largely the burden for chopper mechanism, ensure the reliability and reduce cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cooking appliance with an infrared sensor that detects the temperature of food to be cooked using an infrared sensor and controls cooking according to the detected temperature.

[Technical background of the invention]

Generally, this type of cooking device, such as a microwave oven, is equipped with an infrared sensor facing inside the heating chamber, and a chopper that cuts off the incidence of light to the infrared sensor. The infrared sensor is configured to obtain an AC signal at a level corresponding to the difference between the temperature and the concentration of the chopper. The temperature of the food to be cooked is detected by amplifying and smoothing the output (minimal signal) of the infrared sensor and supplying it to a microcomputer serving as a control section.

As shown in FIG. 4, the infrared sensor and chopper are activated at the same time as cooking starts to detect the temperature of the food to be cooked in the heating chamber, and when the detected temperature of the food to be cooked reaches the set temperature T8, the temperature of the food to be cooked reaches the set temperature T8. Trying to stop cooking.

[Problems with background technology]

However, in such microwave ovens, the chopper is constantly operating from the start to the end of cooking, so the chopper requires a very sturdy mechanism from the standpoint of reliability, which inevitably increases costs. situation. Furthermore, there is a problem in that mechanical noise (collision noise) is generated by the operation of the chopper from the start to the end of cooking, giving a user a feeling of discomfort.

(Object of the invention) This invention was made in view of the above circumstances.
The aim is to significantly reduce the load placed on the chopper mechanism, thereby reducing costs while ensuring sufficient reliability, and also reducing the discomfort caused by chopper operating noise. An object of the present invention is to provide an excellent cooking device with an infrared sensor.

[Summary of the invention]

In this invention, during cooking, the temperature is periodically detected by the infrared sensor, thereby shortening the operating time of the chopper.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In FIG. 3, reference numeral 1 denotes a high-frequency generator, such as a magnetron, which supplies high-frequency radio waves into a heating chamber (not shown). The magnetron 1 is connected to a commercial AC power source 4 via a high voltage transformer 2, a control switch (relay contact) 3, and the like.

On the other hand, 5 is an infrared sensor, which is provided so that its light receiving surface faces the food to be cooked 6 in the heating chamber.

A chopper 7 is arranged near the infrared sensor 5. This chopper 7 is turned on and off by a chopper drive circuit 18, and is configured to intermittent infrared rays emitted from the food 6 in the heating chamber and incident on the light receiving surface of the infrared sensor 5. And Chopper 7
A temperature sensor, such as a thermistor 9, for detecting the temperature of the chopper 7 is disposed near the chopper 7.

Therefore, the output (minimal signal) of the infrared sensor 5 is subjected to signal processing (amplification, smoothing, etc.) in the sensor circuit 10, and then A/D
The signal is supplied to an (analog/digital) converter 11, where it is converted into a digital signal and supplied to a microcomputer 20, which is the main control section. Furthermore, the output signal of the thermistor 9 is transmitted to the sensor circuit 12.
The signal is subjected to signal processing (amplification, etc.) and supplied to the A/D converter 11, where it is converted into a digital signal and supplied to the microcomputer 20.

The microcomputer 20 detects the difference between the temperature of the food 6 and the temperature of the chopper 7 based on a signal output from the infrared sensor 5 and supplied via the sensor port 10 and the A/D converter 11, and calculates the concentration difference. The temperature of the food 6 is detected by correcting the temperature detected by the thermistor 9, that is, the temperature of the chopper 7, and the control switch 3 is controlled according to the detected concentration of the food 6.

Next, the operation of the above configuration will be explained with reference to FIG.

When the food 6 is placed in the heating chamber and a cooking start operation is performed, the microcomputer 20 turns on the control switch 3 and causes the magnetron 1 to oscillate. In this way, high frequency radio waves are supplied into the heating chamber, and the food 6 is dielectrically heated. In other words, cooking begins.

At this time, the microcomputer 20 controls the chopper drive period ta and the chopper stop period t, as shown in FIG.
A chopper drive signal with b as one period to is supplied to the chopper drive 1 path 8. In this way, chopper 7 at a certain time @t
The infrared sensor 5 is turned on and off for a waiting time of ta every time o, and the light entering the infrared sensor 5 is interrupted by the on and off operations. That is, the temperature of the food 6 is detected at a period of to.

Therefore, when the m degrees of the detected food 6 rises to a value TS1 that is 70% of the set temperature Ts, the microcomputer 20 sets the chopper drive period 1i6ta and the chopper stop period (0,5·tb> to -period tol). A chopper drive signal is emitted.Therefore, the chopper 7 is activated at 11t at a certain time.
It turns on and off by taRIl every time o1 (<to), and thereby the temperature of the food 6 is detected at intervals tol.

Then, the microcomputer 20 detects the detected food 6.
The concentration of TS further increases to a value TS of 90% of the set temperature TS.
When it increases to 2, a chopper drive signal is generated in which only the chopper drive 111ta has one cycle t02 (<tol). Therefore, the chopper 7 is turned on and off continuously, and the temperature of the food 6 is thereby successively detected.

In this way, when the temperature of the food 6 reaches the set concentration Ts, the microcomputer 20 turns off the control switch 3 and stops the oscillation operation of the magnetron 1. In other words, cooking will stop.

In this way, since the temperature of the food 6 is periodically detected by the infrared sensor 5, the operating time of the chopper 7 can be shortened and the load placed on the chopper 7 can be significantly reduced. Sufficient reliability can be ensured without making the mechanism very sturdy, and costs can be reduced. Moreover, since the temperature detection period is gradually shortened as it approaches the set concentration, it is possible to accurately detect when the detected temperature reaches the set temperature, and prevent the food 6 from being overheated. It is possible to always cook to a good quality.

Furthermore, since the operating sound (mechanical sound) of the chopper 7 is reduced, discomfort to the user can be reduced.

In the above embodiment, the shortening of the temperature detection cycle is started from 70% of the set temperature Ts, but the point at which shortening of the temperature detection cycle starts may be determined as appropriate depending on the situation. others,
It goes without saying that the present invention is not limited to the embodiments described above, and that various modifications can be made without departing from the gist.

(Effects of the Invention) As described above, according to the present invention, the temperature is periodically detected by the infrared sensor during cooking, so the load on the chopper mechanism can be significantly reduced. Thereby, it is possible to provide an excellent cooking appliance with an infrared sensor that can reduce costs while ensuring sufficient reliability, and can also reduce discomfort caused by the operating noise of the chopper.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining the cycle of temperature detection in an embodiment of the present invention, Fig. 2 is a time chart for explaining the chopper drive signal in the embodiment, and Fig. 3 is an outline of the embodiment. The configuration diagram, FIG. 4, is a diagram for explaining temperature detection of a conventional microwave oven. 5... Infrared sensor, 6... Food to be cooked, 7...
Chopper, 20...Microcomputer (main system part). Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (2)

[Claims] (1) Detect the temperature of the food to be cooked with an infrared sensor,
A cooking appliance with an infrared sensor that controls cooking according to the detected temperature, characterized in that the cooking appliance with an infrared sensor is provided with a control means that periodically detects concentration using the infrared sensor during cooking. (2) The cooking appliance with an infrared sensor according to claim 1, wherein the control means shortens the period of temperature detection as the detected temperature approaches the set temperature.