EP2738473B1

EP2738473B1 - High-frequency cooker

Info

Publication number: EP2738473B1
Application number: EP12817226.9A
Authority: EP
Inventors: Yuji Hayakawa; Ikuhiro Inada
Original assignee: Panasonic Corp
Current assignee: Panasonic Corp
Priority date: 2011-07-26
Filing date: 2012-07-26
Publication date: 2015-11-25
Anticipated expiration: 2032-07-26
Also published as: EP2738473A4; WO2013014940A1; EP2738473A1; JP5747162B2; JP2013024531A

Description

Technical Field

The present invention relates to a high-frequency cooker in which an LED element is used for illuminating an interior of a heating chamber.

Background Art

In a related art, a high-frequency cooker is provided with illumination for an interior of a heating chamber such that the state of food to be heated may be observed. In addition, as a cooker, it is necessary to allow a user to visually recognize that food is heated deliciously.
There has been the illumination for the interior of the heating chamber of the high-frequency cooker in which a filament bulb is provided outside of a wall surface of the heating chamber that shields a radio wave, and a plurality of (punched) holes for illumination are formed in the wall surface. In addition, there has been an illumination device which includes a plurality of LED elements to illuminate food (e.g., see Patent Document 1). An alternative illuminating construction can be seen in prior art document EP2128526 .

Related Art Documents

Patent Documents

Patent Document 1: JP-A-5-164331

Summary of the Invention

Problem to be Solved by the Invention

Radio wave shielding properties of a wall surface portion of a heating chamber provided with illumination holes depend on a thickness of the wall, a pore diameter of the illumination holes, and a pitch between the illumination holes, and intensity of illumination of the heating chamber also depends thereon.
However, in the related-art configuration described above, the pore diameter needs to be reduced in order to improve the radio wave shielding properties, and the pore diameter and the number of the illumination holes need to be increased in order to increase the intensity of illumination. Thus, the radio wave shielding properties and the intensity of illumination inside the heating chamber have a contradictory relation.
In addition, concerning the pitch between the illumination holes, the radio wave shielding properties and the intensity of illumination inside the heating chamber also have a contradictory relation, so that in order to improve the radio wave shielding properties, the pitch between the illumination holes needs to be increased to reduce the number of the illumination holes. This configuration has a problem in that the transmittance of light in an illumination device is decreased, whereby the intensity of illumination of the heating chamber is decreased. Consequently, shadows of bars between the illumination holes are generated, and visibility of food is reduced. Therefore, the power output of the illumination device needs to be increased.
In addition, when LED elements are used in the illumination device, the LED elements are affected by the pore diameter of the illumination holes and the pitch between the illumination holes because the LED elements include small light sources and have high directivity of light. Therefore, there is a problem in that it is necessary to increase the number of the LED elements in order to maintain the intensity of illumination.

Means for Solving the Problem

In order to solve the problem of related art, a high-frequency cooker uses an LED element for chamber illumination in a heating chamber, and an illumination hole provided in a wall surface of the heating chamber for projecting light into an interior of the heating chamber has a quadrilateral shape.
With the configuration, the light from the LED element passes through the quadrilateral hole and if projected onto the interior of the chamber. When passing through the quadrilateral hole, the light can be projected without decreasing the transmittance of light since the LED element provided in the vicinity of the wall surface includes a small light source and has high directivity of light.
The quadrilateral illumination hole has one side located on a rear side of the heating chamber and parallel to a plane of an opening provided on a front surface of the heating chamber, which is longer than one side located on a front side of the heating chamber. Consequently, if an LED element having high intensity is used as the LED element, the light toward the front side can be decreased and the light toward the rear side in the chamber can be increased. Therefore, it is possible to illuminate the entire interior of the chamber with a small number of LED elements while the strong light from the LED element is prevented from entering user's eyes.

Advantages of the Invention

According to the high-frequency cooker of the present invention, since the illumination hole has the quadrilateral shape, the interior of the heating chamber can be illuminated to the corners of the chamber with a small number of LED elements while keeping radio wave shielding properties improved.

Brief Description of the Drawings

FIG. 1(a) is a perspective view of a high-frequency cooker according to an embodiment 1 of the present invention, and FIG. 1(b) is a detailed view of a portion A in the perspective view of FIG. 1(a) of the high-frequency cooker according to the embodiment 1 of the present invention;
FIG. 2 is a perspective view of the high-frequency cooker according to the embodiment 1 of the present invention showing a structure;
FIG. 3 is a structural view of a high-frequency cooker according to an embodiment 2 of the present invention showing a relevant part;
FIG. 4 is a detailed view of a high-frequency cooker according to an embodiment 3 of the present invention showing a relevant part; and
FIG. 5 is a perspective view of a conventional high-frequency cooker showing an illumination structure.

Mode for Carrying Out the invention

A first invention provides a high-frequency cooker which supplies a high frequency to an interior of a heating chamber that houses an object to be heated and which heat-treats the object to be heated, the high-frequency cooker including: an LED element which is used for chamber illumination in the heating chamber, and which is provided in a vicinity of a wall surface of the heating chamber; and an illumination hole provided in the wall surface of the heating chamber for projecting light into the interior of the heating chamber, wherein the illumination hole has a quadrilateral shape, and wherein one side of the quadrilateral illumination hole located on a rear side of the heating chamber and parallel to a plane of an opening provided on a front surface of the heating chamber for inserting and removing the object to be heated is longer than one side of the quadrilateral illumination hole located on a front side of the heating chamber.
Thus, the light from the LED element passes through the quadrilateral hole and is projected onto the interior of the chamber. When passing through the quadrilateral hole, the light can be projected without decreasing the transmittance of light since the LED element provided in the vicinity of the wall surface includes a small light source and has high directivity of light. In addition, since the one side of the quadrilateral illumination hole located on the rear side of the heating chamber and parallel to the plane of an opening provided on the front surface of the heating chamber is longer than the one side located on the front side of the heating chamber, if an LED element having high intensity is used as the LED element, the light toward the front side can be decreased and the light toward the rear side in the chamber can be increased. Consequently, it is possible to illuminate the entire interior of the chamber with a small number of LED elements while the strong light from the LED element is prevented from entering user's eyes.
In a second invention, the LED element includes a plurality of elements, and provides lighting patterns of simultaneous lighting and one-side lighting by a combination of different color temperatures.
Thus, by changing the lighting patters in accordance with the food to be heated to change the color of the light, a subtle color tone of the food can be expressed, or power consumption can be reduced by one-side lighting, whereby energy saving can be achieved.
In a third invention, a transparent diffusing plate is provided between the illumination hole formed in the wall surface of the heating chamber and the LED element, whereby the light projected from the LED element can be diffused by the transparent diffusing plate and projected onto corners of the interior of the heating chamber.
Hereinafter, descriptions of embodiments of the present invention will be provided with reference to the drawings. It is to be noted that the present invention is not limited to the embodiments of the present invention.

(Embodiment 1)

FIG. 1 (a) is a perspective view of a high-frequency cooker according to the first embodiment of the present invention, and FIG. 1(b) is a detailed view of the portion A in the perspective view of FIG. 1(a) of the high-frequency cooker according to the first embodiment of the present invention. FIG. 2 is a perspective view of the high-frequency cooker according to the first embodiment of the present invention showing a structure.
In FIG. 1(a), the main body of the high-frequency cooker according to the first embodiment of the present invention includes a heating chamber 2 having a heating chamber opening 3 through which an object to be heated is inserted and removed, and an illumination hole 1 at the portion A on a wall surface of the heating chamber 2 as shown in FIG. 1(b).
In FIG. 2, the wall surface of the heating chamber is provided with an LED substrate 7 serving as illumination means provided outside of the wall surface, an air guide 5 configured to guide cooling air to the inside of the heating chamber 2, and a substrate holder 9 arranged to fix the LED substrate 7 to the air guide 5 to hold.
Hereinafter, descriptions of the operation and effect of the high-frequency cooker having the configuration described above will be provided.
First, light of an LED element (not shown in the drawing) provided on a surface of the LED substrate 7 provided outside of the wall surface of the heating chamber 2 passes through the illumination hole 1 that has a quadrilateral shape, and is projected onto the interior of the chamber. In this case, since the LED element provided in the vicinity of the wall surface has a light source of 3 mm × 3 mm or 5 mm × 5 mm that is small in size and has also high directivity of light, the light is not hindered from passing through the quadrilateral illumination hole 1 even when a size of the illumination hole 1 is, for example, 5 mm × 5 mm does not affect radio wave shielding properties, whereby the transmittance of light is not decreased.
In addition, one side of the quadrilateral illumination hole 1 located on a rear side of the heating chamber and parallel to the heating chamber opening 3 on a front surface of the heating chamber is longer than one side of the quadrilateral illumination hole 1 located on a front side of the heating chamber. For example, the one side on the rear side of the heating chamber is set to be 7 mm and the one side on the front side of the heating chamber is set to be 5 mm. Consequently, if an LED element having high intensity is used as the LED element, the light toward the front can be decreased and the light toward the rear side in the chamber can be increased, so that it is possible to illuminate the entire interior of the chamber with a small number of LED elements while the strong light from the LED element is prevented from entering user's eyes.

(Embodiment 2)

FIG. 3 is a structural view of a high-frequency cooker according to the second embodiment of the present invention showing a relevant part. It is to be noted that descriptions of parts that are same as or similar to the parts according to the first embodiment of the present invention are omitted or simplified.
In FIG. 3, the wall surface of the heating chamber is provided with a first illumination hole 1a and a second illumination hole 1b through which light of LED elements passes. In addition, a first LED element 7a and a second LED element 7b are provided on a surface of the LED substrate 7. These LED elements are configured by a combination of different color temperatures, and are capable of controlling lighting patterns of simultaneous lighting and one-side lighting.
In the high-frequency cooker having the above-described configuration, for example, by setting the color temperature of the first LED element 7a to be 3000 K and setting the color temperature of the second LED element 7b to be 5000 K, the first LED element 7a having greater color rendering properties is lit alone for food that has a vivid color such as red and green, or the second LED element 7b having the higher color temperature is lit alone when the whiteness of a dish is desired to be accentuated or when the interior of the chamber is desired to be illuminated white and bright at the time of cleaning the chamber. In addition, by lighting the first LED element 7a and the second LED element 7b simultaneously, the two conditions described above can be satisfied.

(Embodiment 3)

FIG. 4 is a detailed view of a high-frequency cooker according to the third embodiment of the present invention showing a relevant part.
In FIG. 4, a transparent diffusing plate 8 is provided between the illumination hole 1 on the wall surface of the heating chamber and the LED substrate 7.
In the high-frequency cooker having the above-described configuration, the light projected from the LED element provided on the LED substrate 7 has high directivity, but can be diffused by the transparent diffusing plate 8 and projected onto the corners of the interior of the heating chamber.
The present invention has been described in detail with reference to the specific embodiments, but it is be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention.
The present application is based on the Japanese Patent Application filed on July 26, 2011 ( No. 2011-162728 ), the contents of which are incorporated herein by reference.

Industrial Applicability

As described above, by using the LED element for chamber illumination inside the heating chamber, and providing the illumination hole having the quadrilateral shape, the high-frequency cooker according to the present invention can illuminate the interior of the chamber brightly to the corners with a small number of LED elements, whereby energy saving and a reduction in cost can be achieved, so that the high-frequency cooker according to the present invention is effective as a high-frequency cooker.

Description of Reference Signs

1: Illumination Hole
2: Heating Chamber
3: Heating Chamber Opening
4: Filament Bulb
5: Air Guide
6: Illumination Punched Hole
7: LED Substrate
8: Transparent Diffusing Plate
9: Substrate Holder
1a: First Illumination Hole
1b: Second Illumination Hole
7a: First LED Element
7b: Second LED Element

Claims

A high-frequency cooker which supplies a high frequency to an interior of a heating chamber that houses an object to be heated and which heat-treats the object to be heated, said high-frequency cooker comprising:
an LED element which is used for chamber illumination in the heating chamber, and which is provided in a vicinity of a wall surface of the heating chamber; and

an illumination hole provided in the wall surface of the heating chamber for projecting light into the interior of the heating chamber,

wherein the illumination hole has a quadrilateral shape, characterised in that

one side of the quadrilateral illumination hole located on a rear side of the heating chamber and parallel to a plane of an opening provided on a front surface of the heating chamber for inserting and removing the object to be heated is longer than one side of the quadrilateral illumination hole located on a front side of the heating chamber.
The high-frequency cooker according to claim 1,
wherein the LED element comprises a plurality of elements, and provides lighting patterns of simultaneous lighting and one-side lighting by combination of different color temperatures.
The high-frequency cooker according to claim 1 or 2,
wherein a transparent diffusing plate is provided between the illumination hole formed in the wall surface of the heating chamber and the LED element, for diffusing the light from the LED element and projecting the light onto corners of the interior of the heating chamber.