Electric heating – Microwave heating – With control system
Reexamination Certificate
2001-02-26
2003-07-01
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
With control system
C219S754000, C219S494000, C374S149000, C099S325000
Reexamination Certificate
active
06586714
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a microwave oven and a control method thereof. More particularly, the present invention relates to a microwave oven with its convenience being improved by suitably controlling movement of a member mounted thereto, and a control method thereof.
2. Description of the Background Art
As described in Japanese Laid-Open Publication Nos. 8-145376 and 9-72549, some of the conventional microwave ovens are provided with an infrared sensor capable of detecting the temperature of a food within a heating chamber. Note that this infrared sensor is capable of including a part of the heating chamber in its field of view, and also capable of moving the field of view. Accordingly, wherever the food is placed in the heating chamber, the infrared sensor can include the food in the field of view, and thus can detect the temperature of the food.
However, the conventional microwave ovens move the field of view of the infrared sensor first from a corner of the heating chamber. In general, the food is often placed in the central region of the heating chamber. Therefore, cooking of the food may be completed before the food is included in the field of view of the infrared sensor. In other words, the conventional microwave ovens may not be able to use the detection result of the infrared sensor for cooking, resulting in degraded convenience.
Moreover, in order to move the field of view of the infrared sensor in such a manner as described above, the infrared sensor is conventionally moved with a motor. However, the field of view of the infrared sensor may not be able to be moved to a correct position due to the problems of such a moving mechanism itself. This will be described with reference to
FIGS. 18 and 19
.
FIGS. 18 and 19
are diagrams illustrating the problems of the moving mechanism using a motor.
FIG. 18
is a diagram showing a gear that rotates according to operation of the motor (motor-side gear
200
) and a gear that is fixed to the infrared sensor (sensor-side gear
100
). The motor-side gear
200
is rotatable in the rotation direction H
1
or H
2
. When the motor-side gear
200
is driven by the motor to rotate in the rotation direction H
1
, the sensor-side gear
100
rotates in the rotation direction J
1
accordingly. When the motor-side gear
200
rotates in the rotation direction H
2
, the sensor-side gear
100
rotates in the rotation direction J
2
accordingly. In response to the rotation of the sensor-side gear
100
in the rotation direction J
1
or J
2
, the infrared sensor is moved, so that the field of view thereof is moved.
Note that the movement distance of the infrared sensor is controlled by controlling the rotation distance of the motor-side gear
200
.
FIG. 19
is an enlarged view of an engaged tooth portion of the two gears shown in FIG.
18
. There is a clearance B between a tooth of the motor-side gear
200
and a tooth of the sensor-side gear
100
engaged therewith. Note that the two gears are rotatable, namely, are not fixed. Accordingly, the clearance between the engaged teeth is not always constant at B. In other words, the clearance is produced only under the tooth of the sensor-side gear
100
in
FIG. 19
, but such a clearance may be produced both above and under the tooth of the sensor-side gear
100
.
Provided that the clearance between the tooth of the motor-side gear
200
and the tooth of the sensor-side gear
100
engaged therewith is not constant, the motor-side gear
200
does not rotate by a constant distance from the start of its rotation until the rotation force thereof is transmitted to the sensor-side gear
100
.
In other words, even if the rotation distance of the motor-side gear
200
is accurately controlled, the movement distance of the infrared sensor cannot be controlled accurately.
Therefore, the conventional microwave ovens may not be able to move the field of view of the infrared sensor by an accurate distance. As a result, the conventional microwave ovens may not be able to include the food within the heating chamber in the field of view of the infrared sensor, resulting in degraded convenience.
Moreover, in order to demonstrate features of the microwave oven at the stores or the like, the conventional microwave ovens have a demonstration function to rotate a turntable and display the remaining cooking time without conducting the heating operation. The conventional microwave ovens provided with the infrared sensor are capable of causing the infrared sensor to detect a temperature without conducting the heating operation as a demonstration.
However, such a demonstration of temperature detection by the infrared sensor in the conventional microwave ovens is conducted with the field of view of the infrared sensor being fixed in position. Therefore, the conventional microwave ovens cannot demonstrate the ability to detect the temperature of the food regardless of the position of the food within the heating chamber, resulting in degraded convenience.
Moreover, some of the conventional microwave ovens are provided with a rotating antenna in order to diffuse microwaves oscillated by a magnetron. This rotating antenna is rotatable. However, the conventional microwave ovens cannot rotate the rotating antenna that directly relates to the heating operation of the magnetron in the demonstration, resulting in degraded convenience.
SUMMARY OF THE INVENTION
The present invention is made in view of the above, and it is an object of the present invention to provide a microwave oven with improved convenience by causing a member for moving a field of view of an infrared sensor to move in an appropriate manner.
It is another object of the present invention to provide a microwave oven with improved convenience by causing a member for moving a field of view of an infrared sensor to move in an appropriate manner when conducting a demonstration.
It is still another object of the present invention to provide a microwave oven with improved convenience by causing a rotating antenna to move in an appropriate manner when conducting a demonstration.
According to one aspect of the present invention, a microwave oven is characterized in that it includes a heating chamber for accommodating an object, an infrared sensor having a field of view within the heating chamber, for detecting a temperature of the object in the heating chamber, and a field-of-view moving portion for moving the field of view of the infrared sensor. Note that the field-of-view moving portion moves the field of view in a central region of the heating chamber when temperature detection by the infrared sensor is started in the microwave oven.
According to the present invention, a food can be more quickly included in the field of view of the infrared sensor when being placed in the central region of the heating chamber.
In the microwave oven, the food is often placed in the central region of the heating chamber. Therefore, in such a case, the food can be more quickly included in the field of view. In other words, heating of the food is less likely to be completed before the food is included in the field of view of the infrared sensor. As a result, convenience of the microwave oven can be improved.
Preferably, the microwave oven according to the present invention further includes a presence determination portion for determining whether or not the object is present within the field of view of the infrared sensor, based on a detection result of the infrared sensor. The field-of-view moving potion preferably extends a movement range of the field of view to a range broader than the central region of the heating chamber, if the presence determination portion determines that the object is not present in the central region of the heating chamber.
As a result, the food can be included in the field of view of the infrared sensor even when being placed in a position other than the central region of the heating chamber.
Preferably, the microwave oven according to the present invention further includes a presence determin
Fukunaga Eiji
Kawamura Kazuhiko
Noda Masaru
Taino Kazuo
Uehashi Hiroyuki
Armstrong Westerman & Hattori, LLP
Leung Philip H.
Sanyo Electric Co,. Ltd.
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