JPH07217897A - Heating and cooking device - Google Patents

Abstract

PURPOSE:To restrict the number of signal lines connected from a light receiving element to a control means irrespective of an increased number of the light receiving elements. CONSTITUTION:A photo-transistor 31 of a light receiving device 30 receives light from an LED 27 of a light emitting device 26 and outputs a light receiving signal corresponding to an amount of received light to a multiplexer 42. The multiplexer 42 is connected to a micro-computer 34 through a signal line 46 and a light receiving signal obtained from the desired photo-transistor 31 is outputted to the micro-computer 34 in response to a control signal obtained from the micro-computer 34. In this case, it is. satisfactory that the number of signal lines 46 is set such that there are up to four lines for the limited number of up to eight of the photo-transistors 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating cooker equipped with an optical sensor for determining the shape of a stored item in a heating chamber.

[0002]

2. Description of the Related Art Conventionally, for example, in a microwave oven, an optical sensor is provided corresponding to a heating chamber, and based on the detection state of the optical sensor, the type of cooked food or accessory stored therein is determined, and The thing which performs heating cooking based on the judgment result is provided. In this case, the optical sensor includes a plurality of light projecting elements and light receiving elements facing each other, and is configured to detect the presence or absence of an object located on the optical axis between them.

FIG. 7 shows an electrical configuration of this kind.
In FIG. 7, the projection unit 1 includes eight LEDs 2
Is mounted and emits light from the LED 2 into a heating chamber (not shown) in a power supply state. Also, eight phototransistors 4 are mounted on the light receiving unit 3, and each phototransistor 4 outputs a light receiving signal according to the amount of light received. A light receiving signal from each phototransistor 4 of the light receiving unit 3 is output to the control unit 6 through the signal line 5. A multiplexer 7 and a microcomputer 8 are mounted on the control unit 6, and the light receiving signal from the phototransistor 4 is output to the input terminal of the multiplexer 7.

The multiplexer 7 selectively selects the light receiving signal from the phototransistor 4 in response to the control signal from the microcomputer 8 being input to the terminals A, B and C, and from the terminal COM to the microcomputer 8. Output. Then, the microcomputer 8 sequentially inputs the light receiving signals from the phototransistors 4 by sequentially switching the control signals through the multiplexer 7, and based on the input light receiving signals, the cooked foods or accessories stored in the heating chamber. Is judged and heating cooking is executed.

According to the above configuration, the phototransistor 4
Since the light receiving signal from is selectively selected by the multiplexer 7 and sequentially output to the microcomputer 8, only one signal input terminal of the microcomputer 8 is required. Therefore, the configuration of the microcomputer 8 can be simplified as compared with the configuration in which the light receiving signal from the phototransistor 4 is input to the microcomputer 8 in parallel.

[0006]

However, in the above-mentioned conventional configuration, the multiplexer 6 is replaced by the control unit 6.
Therefore, the number of signal lines 5 connecting the light receiving unit 3 and the control unit 6 is required to correspond to the number of phototransistors 4. For this reason,
As the number of phototransistors 4 increases, the number of signal lines increases, which increases the cost required for signal line wiring.
There is a drawback in that the probability of interfering with data transmission via the signal line becomes high.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light receiving element in a structure in which cooking is performed by sequentially outputting light receiving signals from a plurality of light receiving elements to a control means through a signal line. Another object of the present invention is to provide a heating cooker capable of suppressing the number of signal lines despite the increase in the number of the cooking appliances.

[0008]

According to the present invention, a light projecting unit is provided so as to project light into a heating chamber, and a light receiving unit composed of five or more light receiving elements is provided so as to face the light projecting unit. Providing signal selection output means for selectively selecting and outputting the light receiving signal from the light receiving element of the light receiving unit,
By switching the signal selecting and outputting means, the light receiving signals from the light receiving element are sequentially input through the signal selecting and outputting means, and the control means for executing the cooking based on the inputted light receiving signal is provided. The signal selection output means is integrated with the light receiving unit and is connected to the control means through a signal line.

In this case, the light projecting unit and the light receiving unit may be provided so as to face the wall surface of the heating chamber.

Further, the light receiving unit may be constructed by mounting the light receiving unit and the signal selecting and outputting means on a printed wiring board.

[0011]

In the heating cooker according to the first aspect, when the light projected from the light projecting unit reaches the light receiving element, the light receiving signal is output from the light receiving element to the signal selection output means. Then, when the signal selecting and outputting means is switched by the controlling means, the signal selecting and outputting means selectively selects and outputs the light receiving signal from the light receiving element. As a result, the control means sequentially inputs the light receiving signals from the light receiving elements through the signal selecting and outputting means, and executes the cooking based on the input light receiving signal.

Here, since the signal selecting and outputting means is integrated with the light receiving unit, the number of signal lines connecting the light receiving unit and the controlling means is the signal for selecting the light receiving element by the signal selecting and outputting means. A line (depending on the number of light receiving elements) and one signal line for outputting a light receiving signal from the signal selecting and outputting means are sufficient. Therefore, when the number of light receiving elements is 5, for example, the number of signal lines between the control means and the signal selection and output means may be four. In this case, in the structure in which the signal selecting and outputting means is provided on the control means side, five signal lines are required corresponding to the number of light receiving elements, so that five light receiving elements are required.
It is possible to reduce the number of signal lines under the condition that the number is more than one.

In the heating cooker according to the second aspect, since the light projecting unit and the light receiving unit are provided to face the wall surface of the heating chamber, the signal line connecting the light receiving unit and the control means becomes long, Further, since the light receiving unit is provided to separate the heating chamber from the control unit, there is a high risk of the signal line coming into contact with the heated heating chamber. However, by reducing the number of signal lines, the heating source is reduced. It is possible to minimize the influence of heat from the device or the influence of noise.

In the heating cooker according to the third aspect, the light receiving unit and the signal selecting and outputting means are mounted on the printed wiring board. It can be miniaturized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a microwave oven will be described below with reference to FIGS. FIG. 2 is a perspective view of the microwave oven, and FIG. 3 schematically shows the structure of the microwave oven. 2 and 3, the main body 11 is provided with a heating chamber 13 which is opened and closed by a door 12,
A rotary plate 15 rotated by an RT motor 14 is arranged at the bottom of the heating chamber 13. This RT motor 14
Is integrally provided with a weight sensor 16 for measuring the weight of the food item placed on the rotating dish.

A machine room 17 provided on the side of the heating room 13
A magnetron 18 as a heating means is arranged in the chamber, and the high frequency wave from the magnetron 18 is radiated into the heating chamber 13 through the waveguide 19. A grill heater 20 as a heating means is provided on the upper surface of the heating chamber 13. The exhaust passage 21 is provided with a gas sensor 22 as a component detecting means for detecting the gas emitted from the food. An oven heater (not shown) as a heating unit is provided on the back surface of the back wall of the heating chamber 13.

On the other hand, the operation panel 23 provided on the front surface of the machine room 17 is provided with an operation input switch 24 for selecting a cooking menu and instructing the start of cooking. A display 25 including an indicator or the like showing the quality of the work is provided.

In FIG. 3, a light projecting unit 26 is arranged on the right wall surface of the heating chamber 13 in the figure. The light projecting unit 26 is configured by mounting eight LEDs 27, which are light projecting elements, on a printed wiring board 28 in a straight line, and the printed wiring board 28 is attached to the outer surface of the heating chamber 13 by a holder (not shown). LED27 by doing
Faces inside the heating chamber 13 through a hole 29 formed in the wall surface of the heating chamber 13. A light receiving unit 30 is provided on the left wall surface of the heating chamber 13 in the drawing.

This light receiving unit 30 is constructed by mounting eight phototransistors 31, which are light receiving elements, on a printed wiring board 32 in a straight line, and the printed wiring board 32 is attached to the outer surface of the heating chamber 13 by a holder (not shown). Each phototransistor 31 is attached to the heating chamber 1
The inside of the heating chamber 13 is exposed through the hole 33 formed in the wall surface of the No. 3. In this case, the LEDs 27 and the phototransistors 31 are arranged to face each other, and the light projected from the LEDs 27 is set to reach only the phototransistors 31 that face each other.

FIG. 4 schematically shows the overall electrical configuration. In FIG. 4, a microcomputer 34 having a function as a control means is a CPU 35, a ROM
36, RAM 37 and the like. The weight sensor 16 is connected to the input terminal of the microcomputer 34,
A gas sensor 22, a door switch 38 that turns on and off according to opening and closing of the door 12, an operation input switch 24 are connected, a buzzer 39 and an indicator 25 are connected to output terminals, and the RT motor 14 is connected via a drive circuit 40. , A magnetron 18, a grill heater 20 and an oven heater (not shown) are connected.

Further, the microcomputer 34 controls the power supply to the light projecting unit 26 and inputs the light receiving signal from the light receiving unit 32.

FIG. 1 shows the connection relationship between the light projecting unit 26, the light receiving unit 30, and the microcomputer 34. In FIG. 1, the LED 27 mounted on the printed wiring board 28 of the light projecting unit 26 has two anodes.
The 0V line is connected to the cathode and the 0V line is connected to the cathode.
Light is emitted from 7.

The printed wiring board 32 of the light receiving unit 30
The collector of the phototransistor 31 mounted on the is connected to the connector 41, and the emitter is connected to the input terminal of the multiplexer 42 which is the signal selection output means. Are output to the multiplexer 42.

The multiplexer 42 has three control terminals (terminals A, B, and C), eight signal input terminals (terminals 0 to 7), and one common output terminal (terminal COM).
A predetermined signal input terminal among the eight signal input terminals is connected to the common output terminal according to the combination of the input levels of the control terminals. In this case, the emitter of each phototransistor 32 is connected to the signal input terminal of the multiplexer 42. In addition, the multiplexer 42
The control terminal, common output terminal, and power supply terminal (terminal VDD) are connected to the connector 41. Here, FIG. 5 shows the multiplexer 42, and FIG. 6 shows a truth table of the multiplexer 42.

On the other hand, in FIG. 1, the microcomputer 34 for executing the cooking is a printed wiring board 4
It is installed in 3. 3 in the microcomputer 34
Control signal output terminals (terminals A, B, C) are provided and one signal input terminal (terminal SIN) is provided. The printed wiring board 43 has a connector 4
4 is attached, and the connector 44 is connected to the three control signal output terminals of the microcomputer 34 and the 5V power supply line.

A power line 45 and four signal lines 46 are connected between the connector 41 and the connector 44, and the power line 45 connects the power terminal of the multiplexer 42 to the 5V power line. By the connection by the signal line 46, the control terminal of the multiplexer 42 is connected to the control signal output terminal of the microcomputer 34, and the common output terminal is connected to the signal input terminal of the microcomputer 34.

The 0V line of the printed wiring board 28 of the light projecting unit 26, the printed wiring board 32 of the light receiving unit 30 and the printed wiring board 43 on which the microcomputer 34 is mounted is connected through a metal casing. In this case, each 0V line may be connected through a power line.

Next, the operation of the above configuration will be described. When the start of cooking is instructed by the operation input switch 24, the microcomputer 34 first sets all the output levels of the control signal output terminals to "L". Then, all the input levels of the control terminals of the multiplexer 42 become "L", so that the multiplexer 42 outputs the light receiving signal from the first phototransistor 31 to the common output terminal according to the truth table shown in FIG. . As a result, the light receiving signal from the first phototransistor 31 is input to the signal input terminal of the microcomputer 34, so that the microcomputer 34 determines that the first LED 27 and the first phototransistor are in accordance with the input level. 31
It is possible to determine whether or not an object exists on the optical axes of and.

Similarly, the microcomputer 34
6 sequentially inputs the light receiving signals from the second to eighth phototransistors 31 through the multiplexer 42 by sequentially setting the output levels of the control signal output terminals according to the truth table shown in FIG. Then, the microcomputer 34 sets the cooking course by determining the size of the food or the type of the accessory based on the combination of the signal levels of the light receiving signals from the phototransistors 31, and the weight sensor 16 is set. After setting the heating cooking time based on the weight signal from, the magnetron 18 is driven to perform the heating cooking.

According to the above configuration, the light receiving unit 3
Since the multiplexer 42 is integrated with 0, and the multiplexer 42 and the printed wiring board 43 on which the microcomputer 34 is mounted are connected through the signal line 46, the printed wiring board 32 and the printed wiring board 43 are connected to each other. The number of signal lines 46 between the two is only four. Therefore, in the case of the conventional configuration in which the multiplexer 42 is mounted on the printed wiring board 43 on which the microcomputer 34 is mounted, eight signal lines are required, while the number of signal lines 46 is significantly reduced. You can In this case, if five phototransistors 31 are provided in the conventional configuration, five signal lines are required, so this embodiment is effective in a configuration having five or more phototransistors 31.

Further, since the multiplexer 42 is integrated with the light receiving unit 30 so that the multiplexer 42 is mounted on the printed wiring board 32 for receiving light, it is possible to reduce the size while achieving the integration.

Further, in the present embodiment, the light receiving unit 30 is provided on the wall surface of the heating chamber 13 located on the side opposite to the machine room 17, and the printed wiring board 3 of the light receiving unit 30 is provided.
2 and the printed wiring board 43 arranged in the machine room 17 have a long wiring distance, but the number of the signal lines 46 is 4 as described above, and thus the signal line 46 is sufficient. The cost of itself and the wiring cost can be significantly reduced.

Further, since the number of the signal lines 46 can be reduced, the distance between the signal lines 46 can be set to be large. Therefore, even if the temperature inside the main body 11 becomes high in the case of grill cooking or oven cooking, the signal lines 46 can be heated. Compared to the configuration of bundling because of the large number of 46, the signal line 46
Has good heat dissipation, and the signal line 4
It is possible to prevent the coating of 6 from being melted and improve the reliability of signal transmission.

In addition, the longer the signal line 46 is, the easier the noise generated when the magnetron 18 or the heater is turned on and off is to enter the signal line 46. However, the noise is introduced by reducing the number of signal lines 46. Since it is possible to greatly reduce the probability of the signal transmission, it is possible to further improve the reliability of signal transmission.

The present invention is not limited to the above embodiment, but can be modified or expanded as follows.
The light projecting unit 26 may use a surface light source, specifically, an EL panel or a so-called backlight using a fluorescent tube. A photodiode or CdS may be used as the light receiving element of the light receiving unit 30. Also,
It can be applied to cookers other than microwave ovens.

[0036]

According to the cooking device of the present invention, the signal selecting and outputting means for selectively selecting and outputting the light receiving signals from the plurality of light receiving elements of the light receiving unit is integrated with the light receiving unit, and Since the light receiving signals from the signal selecting and outputting means are sequentially output to the controlling means through the signal lines, the light receiving signals from the plurality of light receiving elements are sequentially output to the controlling means through the signal lines to perform the cooking. The excellent effect that the number of signal lines can be suppressed despite the increase in the number of light receiving elements is achieved.

[Brief description of drawings]

FIG. 1 is a diagram showing connections between printed wiring boards in an embodiment of the present invention.

FIG. 2 is a perspective view of a microwave oven.

FIG. 3 is a vertical sectional view schematically showing the structure of a microwave oven.

FIG. 4 is a schematic diagram showing an electrical configuration.

FIG. 5 is an explanatory diagram of terminals of a multiplexer.

FIG. 6 Trux table of multiplexer

FIG. 7 is a view corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

13 is a heating chamber, 26 is a light projecting unit, 27 is an LED, 3
Reference numeral 0 is a light receiving unit, 31 is a phototransistor (light receiving element), 32 is a printed wiring board, 34 is a microcomputer (control means), and 46 is a signal line.

Claims (3)

[Claims] 1. A light projecting unit provided so as to project light into a heating chamber, a light receiving unit composed of five or more light receiving elements provided so as to face the light projecting unit, and a light receiving unit. A signal selection output means for selectively selecting and outputting a light reception signal from the element, and a light reception signal from the light receiving element is sequentially input through the signal selection output means by switching the signal selection output means. Control means for executing heating and cooking based on the received light receiving signal, wherein the signal selecting and outputting means is integrated with the light receiving unit and connected to the control means through a signal line. Cooker to cook. 2. The heating cooker according to claim 1, wherein the light projecting unit and the light receiving unit are provided so as to face a wall surface of the heating chamber. 3. The heating cooker according to claim 1, wherein the light receiving unit is configured by mounting the light receiving unit and the signal selecting and outputting means on a printed wiring board.