Converging mirror furnace

Patent metadata

Field	Value
Publication number	US-9777375-B2
Application number	US-201214362348-A
Country	US
Kind code	B2
Filing date	Nov 30, 2012
Priority date	Dec 2, 2011
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

Provide a converging mirror-based furnace for heating a target by way of reflecting from a reflecting mirror unit the light emitted from a light source and then irradiating a target with the reflected light, wherein said target-heating converging-light furnace is such that: the reflecting mirror unit comprises a primary reflecting mirror and secondary reflecting mirror; the light emitted from the light source is reflected sequentially by the primary reflecting mirror and secondary reflecting mirror and then irradiated onto the target; and the light reflected by the secondary reflecting mirror and irradiated onto the target surface is not perpendicular to the target surface. Based on the above, a system that uses converged infrared light to provide heating can be made smaller while keeping its heating performance intact, even when the system uses a revolving ellipsoid.

First claim

The invention claimed is:

1. A converging mirror-based furnace for heating a target by causing light emitted from a light source to be reflected by a reflecting mirror unit to irradiate the target,
wherein at least one reflecting mirror unit with a light source installed inside is provided;
the reflecting mirror unit is formed by combining two spheroidal mirrors each having a reflecting surface constituted by the interior surface of a spheroid having a full-circle cross section, where one of the spheroidal mirrors is referred to as a primary reflecting mirror and the other, a secondary reflecting mirror;
a light source is installed in the primary reflecting mirror wherein the light source is positioned at one focal point of the primary reflecting mirror, while an opening provided in the primary reflecting mirror is inter-connected with an opening provided in the secondary reflecting mirror wherein another focal point of the primary reflecting mirror is positioned at one focal point of the secondary reflecting mirror, and the reflecting mirror unit is provided wherein another focal point of the secondary reflecting mirror is positioned on the normal line which passes through a center point of the surface-to-be-heated of the target placed in the furnace, with the opening provided at a side of the other focal point in the secondary reflecting mirror so that the light passes through the opening toward the surface-to-be-heated to irradiate the surface-to-be-heated, said light source being entirely surrounded by the primary reflecting mirror except for the opening of the primary reflecting mirror as viewed from the opening; and
the long axis of an ellipsoid body constituting the secondary reflecting mirror is positioned diagonally to the normal line of the surface-to-be-heated,
wherein the ratio of the major axis to the minor axis of the ellipse configuring the primary reflecting mirror is equal to or less than the ratio of the major axis to the minor axis of the ellipse configuring the secondary reflecting mirror.

2. A converging mirror-based furnace according to claim 1 , wherein the primary reflecting mirror and secondary reflecting mirror are connected wherein the light source is positioned along a straight line connecting the two focal points on the ellipse of the secondary reflecting mirror.

3. A converging mirror-based furnace according to claim 1 , wherein the primary reflecting mirror and secondary reflecting mirror are connected wherein the two focal points on the ellipse of the primary reflecting mirror and two focal points on the ellipse of the secondary reflecting mirror are not present on the same straight line.

4. A converging mirror-based furnace according to claim 1 , wherein the angle formed by the surface of the target and the line connecting the two focal points on the ellipse of the secondary reflecting mirror is 20 to 70°.

5. A converging mirror-based furnace for heating a target by causing light emitted from a light source to be reflected by a reflecting mirror unit to irradiate the target,
wherein at least one reflecting mirror unit with a light source installed inside is provided;
the reflecting mirror unit is formed by combining a primary reflecting mirror being spheroidal mirror whose reflecting surface is constituted by the interior surface of a spheroid having a full-circle cross section, with a secondary reflecting mirror being an entirely revolving paraboloidal mirror whose reflecting surface is constituted by the interior surface of a revolving paraboloidal mirror;
the light source is installed in the primary reflecting mirror wherein the light source is positioned at one of two focal points on the primary reflecting mirror, while an opening provided in the primary reflecting mirror is inter-connected with an opening provided in the secondary reflecting mirror wherein the other focal point of the primary reflecting mirror is positioned at a focal point of the secondary reflecting mirror, and a converging mirror unit is provided wherein a rotational axis of the revolving paraboloidal mirror constituting the secondary reflecting mirror and a center point of a surface-to-be-heated of the target placed in the furnace are positioned along one straight line, with the opening in the secondary reflecting mirror facing the target so that the light is irradiated onto the surface-to-be-heated, said light source being entirely surrounded by the primary reflecting mirror except for the opening of the primary reflecting mirror as viewed from the opening; and
the rotational axis of the secondary reflecting mirror is not perpendicular to the surface of the target.

6. A converging mirror-based furnace according to claim 5 , where the shortest distance between a focal point of the primary reflecting mirror and an elliptic surface thereof is greater than the shortest distance between a focal point of the secondary reflecting mirror and a parabolic surface thereof.

7. A converging mirror-based furnace according to claim 5 , wherein the primary reflecting mirror and secondary reflecting mirror are connected wherein the two focal points on the primary reflecting mirror are positioned along a line extended from the rotational axis of the secondary reflecting mirror being a revolving paraboloidal mirror.

8. A converging mirror-based furnace according to claim 5 , wherein the primary reflecting mirror and secondary reflecting mirror are connected wherein the two focal points on the primary reflecting mirror are not positioned along a line extended from the rotational axis of the secondary reflecting mirror being a revolving paraboloidal mirror.

9. A converging mirror-based furnace according to claim 5 , wherein the angle formed by the line normal to the surface-to-be-heated and the rotational axis of the secondary reflecting mirror is 20 to 70°.

10. A converging mirror-based furnace for heating a target by causing light emitted from a light source to be reflected by a reflecting mirror unit to irradiate the target,
wherein the reflecting mirror unit has a primary reflecting mirror whose reflecting surface is a part of the interior surface of a ring drawn by rotating around the normal line a closed curved line which is present on the same plane as the normal line passing through the center of the surface-to-be-heated and not intersecting with the normal line;
a light source is installed in the ring that forms the primary reflecting mirror having a ring-shaped, in a manner being arranged over the ring either partially or entirely along the circumferential direction;
the target is set on a plane perpendicular to the normal line but not intersecting with the ring, with a slit provided in the reflecting surface near the point of intersection between the shortest straight line connecting the center of the surface-to-be-heated and light source on one hand and the reflecting surface on the other, in order to irradiate the light onto the target; and
the end of the primary reflecting surface where the slit is formed is connected to the reflecting surface that forms the secondary reflecting surface.

11. A converging mirror-based furnace according to claim 10 , wherein the angle formed by the normal line and the line connecting the light source and the center of the target surface is 20 to 70°.

12. A converging mirror-based furnace according to claim 10 , wherein a ring-shaped light source is installed in a circular pattern in the ring that forms the ring-shaped primary reflecting mirror, and a reflecting surface of the reflecting plate that converges the light from the ring-shaped light source onto the surface-to-be-heated is installed perpendicularly to the circle formed by the ring-shaped

Assignees

• Nat Inst Advanced Ind Science & Tech

Inventors

• Ikeda Shinichi
• Hara Shiro
• Mikahara Takanori
• Habuka Hitoshi
• Khumpuang Sommawan

Classifications

• H10P72/0436

  mainly by radiation · CPC title

• H01L21/67115

  Electricity · mapped topic

• C23C16/482 Primary

  using incoherent light, UV to IR, e.g. lamps · CPC title

• F27B17/0025 Primary

  specially adapted for treating semiconductor wafers · CPC title

• F27D2099/0026

  with a generator of electromagnetic radiations · CPC title