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US-20260129725-A1 - A MICROWAVE OVEN WITH A LIGHT SOURCE

US20260129725A1US 20260129725 A1US20260129725 A1US 20260129725A1US-20260129725-A1

Abstract

A microwave oven includes a chamber ( 6 ) for receiving foodstuff. A microwave generator ( 20 ) feeds microwave radiation to the chamber ( 6 ) via a recess ( 14 ). A stirring wheel ( 24 ) is arranged in recess ( 14 ) for homogeneously distributing the microwave field in the chamber ( 6 ). A light source ( 28 ) is provided for illuminating the chamber ( 6 ). Its light passes through a light guide ( 30 ) extending through the recess ( 14 ) past stirrer wheel ( 24 ), thereby preventing the stirrer wheel ( 24 ) from affecting the illumination.

Inventors

  • Robert KÜFFER

Assignees

  • V-ZUG AG

Dates

Publication Date
20260507
Application Date
20211026

Claims (20)

  1. 1 . A microwave oven comprising a foodstuff chamber, a recess arranged in a chamber wall of the chamber, wherein the recess has a rear wall on a side opposite to said chamber and side walls connecting the rear wall to the chamber, wherein a direction perpendicular to the chamber wall defines a depth direction, with the rear wall located deeper than the chamber wall, a microwave generator connected to the recess, a light source, and a stirrer wheel arranged in the recess between the rear wall and the chamber, wherein the stirrer wheel is rotatable around an axis, wherein the oven further comprises a light guide extending from the light source through at least one of an opening in the rear wall and at least one of the side walls into the recess, wherein the opening is located at the same depth as or deeper than the stirrer wheel, and wherein a chamber-facing end of the light guide is located such that an exit cone of light emerging from the light guide does not intersect with a motion of the stirrer wheel.
  2. 2 . The microwave oven of claim 1 wherein the opening is located in the rear wall.
  3. 3 . The microwave oven of claim 1 wherein the light guide extends, at least within the recess, along a direction parallel to the axis.
  4. 4 . The microwave oven of claim 1 wherein the light guide is a straight rod extending from the light source into the recess.
  5. 5 . The microwave oven of claim 1 wherein the stirrer wheel comprises at least one blade rotatable about the axis, wherein the chamber-facing end of the light guide is at least as close to the chamber as the blade(s), in particular at least 1 mm closer to the chamber than the blade(s).
  6. 6 . The microwave oven of claim 1 wherein the chamber comprises a bottom chamber wall, a top chamber wall, and side chamber walls extending between the bottom chamber wall and the top chamber wall, and wherein the microwave oven further comprises a door forming at least part of one of the side chamber walls, and wherein the recess is located in the top chamber wall.
  7. 7 . The microwave oven of claim 1 wherein, in an operating position of the oven, the rear wall of the recess extends horizontally.
  8. 8 . The microwave oven of claim 1 further comprising a transparent cover plate between the chamber and the recess, wherein the cover plate comprises a diffusor for scattering the light from the light guide, and in particular wherein the rear wall extends parallel to the cover plate.
  9. 9 . The microwave oven of claim 1 further comprising a metallic shield member connected to the rear wall, wherein the light guide extends through an opening in the shield member.
  10. 10 . The microwave oven of claim 9 wherein the shield member surrounds the light guide for a length of at least 1 cm, in particular at least 3 cm, along an axial direction of the light guide.
  11. 11 . The microwave oven of claim 9 wherein a diameter of the opening in the shield member is less than 1 cm.
  12. 12 . The microwave oven of claim 9 wherein the light source is mounted to the shield member.
  13. 13 . The microwave oven of claim 9 further comprising a mounting plate mounted to the shield member, wherein the shield member extends between the rear wall and the mounting plate and is connected to the mounting plate, wherein the light source is mounted to the mounting plate on a side facing away from the chamber, and wherein the mounting plate comprises an opening between the light source and the light guide.
  14. 14 . The microwave oven of claim 13 further comprising an anchor releasably engaging the opening in the mounting plate, wherein the light source is mounted to the anchor.
  15. 15 . The microwave oven of claim 1 wherein the light guide is located between the stirrer wheel and a corner of the recess.
  16. 16 . The microwave oven of claim 1 wherein the light guide is of a transparent solid.
  17. 17 . The microwave oven of claim 1 wherein the stirrer wheel is closer to the chamber than the opening through which the light guide enters the recess.
  18. 18 . The microwave oven of claim 1 wherein a closest distance between the light guide and any of the lateral walls is at least 1 cm.
  19. 19 . The microwave oven of claim 1 wherein a closest distance between a chamber-facing end of the light guide and an edge of the recess is at least 1 cm.
  20. 20 . The microwave oven of claim 1 wherein the 30 light guide is located horizontally beside the stirrer wheel in a space between the stirrer wheel and the side walls.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a National Stage application of International Patent Application No. PCT/EP2021/079641, filed on Oct. 26, 2021, which is hereby incorporated by reference in its entirety. TECHNICAL FIELD The invention relates to a microwave oven with a light source. BACKGROUND EP 2991451 describes a microwave oven with a light source. The microwave oven comprises a foodstuff chamber and a recess arranged in the top wall of the chamber. A microwave generator connected to recess feeds microwave radiation into the chamber. The oven further comprises light sources arranged at the top and side wall of the recess. Typically, microwave ovens are equipped with a turntable or a stirrer wheel to homogeneously distribute the microwave radiation within the chamber. SUMMARY The problem to be solved by the present invention is to provide a microwave oven with an improved illumination. This problem is solved by the microwave oven of claim 1. Accordingly, the microwave oven comprises at least the following elements: A foodstuff chamber: This is a microwave-tight chamber for receiving the foodstuff to be heated. Typically, it has the shape of a cuboid with a door at a front side for loading/unloading the foodstuff.A recess arranged in a wall of the chamber: This recess forms a set-back region, which is typically located outside the cuboid of the chamber. The recess has a rear wall on a side opposite to the chamber and side walls connecting the rear wall to the chamber. The direction perpendicular to the chamber wall is designated as the “depth direction” and used to designate locations of components within the description and claims, with terms such as “deeper” or “at the same depth” referring to this depth direction. By definition, the rear wall is located deeper than the chamber wall.A microwave generator connected to the recess: The microwave generator is adapted to generate microwave radiation and feed it, via the recess, to the chamber.A stirrer wheel arranged in the recess between the rear wall and the chamber: The stirrer wheel is rotatable around an axis, typically by means of a stirrer wheel drive. The microwave oven may be adapted to rotate the stirrer wheel while feeding microwave radiation to the chamber in order to achieve a more homogeneous distribution of the radiation within the chamber.A light source: The light source is positioned to feed light into the chamber.A light guide extending from the light source through an opening in the rear wall or at least one of the side walls and into the recess: This light guide allows to place the light source away from the chamber, thereby reducing its exposure to heat and/or radiation. The opening is located deeper than the stirrer wheel (i.e. farther away from the chamber) or at the same depth as the stirrer wheel (i.e. at the same distance from the chamber as at least parts of the stirrer wheel). In particular, the opening is farther away from the chamber than the blades of the stirrer wheel or at the same distance from the chamber as at least parts of the blades. On the other hand, the chamber-facing end of the light guide is located such that the exit cone of the light emerging from the light guide is outside the space occupied by the stirrer wheel, i.e. it does not intersect with the motion of the rotating stirrer wheel. In other words, the exit cone does not intersect with the moving peripheral parts of the stirrer wheel. In this context, the “exit cone” is the space volume around the exit axis of the light guide that includes at least 75%, in particular at least 90%, of the light directly emerging from the chamber-facing end of the light guide. (Note: Even though the term “cone” is used, the volume of the exiting light need not be exactly rotational symmetric if the light guide does not have circular but e.g. oval cross section.) Hence, as seen along the axis of the light guide, the light guide extends over at least part of the stirrer wheel. This design allows to carry the light past the stirrer wheel towards the chamber. Hence, the light emerging from the light guide is not significantly affected by the current position of the stirrer wheel, which reduces the flicker caused by the motion of the stirrer wheel and provides a more steady illumination within the chamber. Advantageously, for easier assembly, the opening is located in the rear wall, i.e. the light guide passes through the rear wall. Advantageously, the chamber-facing end of the light guide is at least as close to the chamber as the part of the blades of the stirrer wheel that is closest to the chamber. In particular, the light guide enters the recess through an opening in the rear wall. The stirrer wheel (i.e. its rotating blades) is closer to the foodstuff chamber than said opening, i.e. the light guide carries the light from the rear side of the wheel (i.e. the side of the wheel facing away from the chamber) past the wheel. Advantageously, the microwave ove