Electric heating – Microwave heating – With control system
Reexamination Certificate
2001-04-26
2003-10-07
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
With control system
C219S494000, C099S325000, C374S149000
Reexamination Certificate
active
06630655
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to microwave ovens and particularly to microwave ovens having an infrared detection element and operative in response to an output from the infrared detection element to provide a heat-cooking operation.
2. Description of the Background Art
Japanese Patent Publication No. 4-68756 discloses a conventional microwave oven employing an infrared detection element to detect a temperature profile on the turntable to detect the position and temperature of a food to be heated that is placed on the turntable.
In such a conventional microwave oven, however, the infrared detection element can only detect the amount of infrared radiation in a limited area (or a field of view), i.e., on the turntable. As such, if such a microwave oven does not have a turntable and a food is placed in the oven's heating chamber at a location at which a turntable would otherwise be provided, the infrared detection element's output cannot fully be used to detect the temperature of the food in the heating chamber.
Furthermore, in a conventional microwave oven, with an infrared sensor arranged in a manner, the heating chamber often can have a large number of areas that cannot be covered by the field of view of the infrared detection element. If in such a case a food is placed at a location that the field of view cannot cover, the infrared sensor's output can also not fully used to detect the condition of the object to be heated.
Furthermore, if juice and the like scattering from a food in the heating chamber adheres to the component of the infrared detection element receiving infrared radiation, it can prevent the infrared detection element from accurately detecting the temperature of the object to be heated. In such a case, the infrared sensor's output can also not fully be used to detect the condition of the object to be heated.
SUMMARY OF THE INVENTION
The present invention has been made to overcome such disadvantages as above and it contemplates a microwave oven employing an infrared sensor having an infrared detection element mounted thereto to ensure that the temperature of an object to be heated is detected to make full use of an output of the infrared sensor to detect the condition of the object to be heated.
The present invention in one aspect provides a microwave oven having a heating chamber accommodating an object to be heated, includes a plurality of infrared detection elements having their respective fields of view in the heating chamber to detect an amount of infrared radiation in the fields of view, the plurality of infrared detection elements being arranged to have the fields of view covering an area in the heating chamber in a first direction from one end to the other end.
In the present invention in one aspect wherever in the heating chamber in the first direction there may exist the object to be heated the infrared detection elements are not required to be moved and their outputs can be used to detect the temperature of the object to be heated.
Thus the infrared detection elements' outputs can be made full use of to detect the condition of the object to be heated.
The present invention in another aspect provides a microwave oven having a heating chamber accommodating an object to be heated includes: an infrared detection element having a field of view in the heating chamber and attached to the heating chamber in a first direction on one side to detect an amount of infrared radiation in the field of view; and a drive unit driving the infrared detection element to move in a second direction traversing the first direction.
Thus if the infrared detection element is moved its field of view can have an area free of a significant variation in size in the heating chamber.
This can enhance the precision of the temperature of the object to be heated that is derived from an output of the infrared detection element.
The present invention in another aspect provides a microwave oven having a heating chamber accommodating an object to be heated, includes: an infrared detection element having a field of view in the heating chamber and attached to the heating chamber in a first direction on one side to detect an amount of infrared radiation in the field of view; and a drive unit driving the infrared detection element to pivot around an axis corresponding to a line orthogonal to a plane formed by the field of view and extending in one direction closest to one side.
With the drive unit driving the infrared detection element to pivot by a predetermined angle, the heating chamber in the first direction on one side and the other side can have less area that is not covered by the field of view of the infrared detection element. More specifically, the heating chamber can be entirely covered by the field of view of the infrared detection element that pivots by a further reduced angle.
Thus temperature can be detected throughout the heating chamber over a wide area.
The present invention in still another aspect provides a microwave oven having a heating chamber accommodating an object to be heated includes: an infrared detection element having a field of view in the heating chamber to detect an amount of infrared radiation in the field of view; a decision unit determining from an output received from the infrared detection element whether the field of view covers the object to be heated; and a drive unit driving the infrared detection element to move the field of view in the heating chamber, wherein if with the drive unit moving the field of view at a first rate the decision unit determines that in the heating chamber at an area there exists the object to be heated then the drive unit is controlled to move the field of view in the area at a second rate to determine that in the area at a specific subarea there exists the object to be heated, the second rate being lower than the first rate.
Thus in the heating chamber the object to be heated can soon be located.
Thus if the object in the heating chamber is heated for a short period of time its temperature can be detected accurately. That is, if the object in the heating chamber is heated for a short period of time the output of the infrared detection element can be made full use of.
The present invention in another aspect provides a microwave oven having a heating chamber having a wall provided with a window, and accommodating an object to be heated, includes: an infrared detection element provided external to the heating chamber and having a field of view in the heating chamber via the window to detect an amount of infrared radiation in the field of view; a cylinder surrounding the window and extending from the window outwardly of the heating chamber; and a drive unit driving the infrared detection element to move. The cylinder has a specific portion increased in height than a remaining portion of the cylinder. The infrared detection element has a detection window introducing infrared radiation into the infrared detection element. The drive unit drives the infrared detection element to move to allow the detection window to face the specific portion if the infrared detection element is not operated to detect infrared radiation.
Thus the cylinder can be formed by barring a sidewall of the heating chamber and at the specific portion of the cylinder increased in height than the remaining portion of the cylinder the infrared detection element can wait when it is not operated for detection.
As such when it is not operated for detection the infrared detection element can be free from contamination otherwise resulting in an impaired precision in detection. Thus the infrared detection element can provide an output that can more effectively be used to detect the temperature of the object to be heated. Furthermore, readily, without using any additional member and at low cost, and at a location closer to the position of the infrared detection element when it is operated for detection, there can be provided a location for the infrared detection element to wait at
Fukunaga Eiji
Kume Kenji
Mukumoto Eiji
Noda Masaru
Taino Kazuo
Armstrong Westerman & Hattori, LLP
Leung Philip H.
Sanyo Electric Co,. Ltd.
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