Light distribution control method, light distribution control device, and greenhouse using the same

• US 20080219010A1
• Filed: 03/06/2007
• Published: 09/11/2008
• Est. Priority Date: 03/06/2007
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha S.T.I. Japan
• Original Assignee: Kabushiki Kaisha S.T.I. Japan
• Inventors: Oyama, Nobuo
• Granted Patent: US 7,843,639 B2
• Time in Patent Office: Days
• US Class Current: 362/322
• CPC Class Codes: A01G 9/22 Shades or blinds for greenhouses, or the like
• CPC Class Codes: A01G 9/243 Collecting solar energy in general F24S
• CPC Class Codes: E06B 9/24 Screens or other constructions affording protection against light, especially against sunshine; Similar screens for privacy or appearance; Slat blindsoperating, guiding or securing devices or arrangements for roll-type closures E06B9/56; free-hanging flexible screens A47H23/00
• CPC Class Codes: F21S 11/00 Non-electric lighting devices or systems using daylight roofs with sky-light opening E04D13/03; sun blinds for windows with means for redirecting light onto ceiling of a room E06B9/00; hybrid lighting devices combining artificial and natural light F21S19/00; solar heat collectors F24S; solar cells or solar cell modules H01L31/00
• CPC Class Codes: G02B 5/0215 the surface having a regular structure
• CPC Class Codes: G02B 5/0221 the surface having an irregular structure G02B5/0226 takes precedence
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/0284 used in reflection
• CPC Class Codes: G02B 5/18 Diffraction gratings holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44
• CPC Class Codes: Y02A 40/25 Greenhouse technology, e.g. cooling systems therefor
• CPC Class Codes: Y02P 60/12 using renewable energies, e.g. solar water pumping

Abstract

Provided is a plurality of structures each having a number of ridges and formed in a long and thin plate shape or a long and thin film shape. The cross section of each of the ridges forms a portion of a substantial circle and a surface thereof is a practically specular surface. The structures are arrayed such that the ridges of each thereof become parallel to each other and respective adjacent surfaces thereof are corresponding to each other in parallel and apart from each other at a predetermined distance. When light is incident on a point of a surface of one of the structures at an incident angle, in either its reflection or transmittance, the light is diffused in circular conical plane whose vertex is the incident point and center axis is a line parallel to the ridges, by a diffraction effect caused by the arrayed ridges. The flux of reflected diffused light is spread in one lengthwise half of the circular conical plane and the flux of transmitted diffused light is spread in the other lengthwise half of the circular conical plane.

Claims

1. A light distribution control method using structures each of which is formed in a plate-like shape or a film-like shape with at least one of optical transparency and optical reflectivity, and comprises a number of ridges arrayed in parallel on at least one of the surfaces of the structure and placed sufficiently/substantially close to each other, each of the ridges having its cross section orthogonal to the longitudinal direction of the ridges, formed in a portion of a substantial circle, and the surface practically specular, resulting in incident light on such a number of ridges being diffused in a circular conical plane-like or a half-circular conical plane-like having the center axis with a line passing the incident point of the incident light and parallel to the ridges.

2. A light distribution control device, comprising:

a plurality of structures, each of which is formed in a plate like shape and a film like shape with at least one of optical transparency and optical reflectivity, and includes a number of ridges which are arrayed in parallel on at least one of the surfaces of the each structure and placed sufficiently/substantially close to each other, each of the ridges having its cross section orthogonal to the longitudinal direction of the ridges, formed in a portion of a substantial circle, and the surface practically specular, the structures being arrayed such that the ridges are parallel to each other and the corresponding surfaces of the adjacent two of the structures are in parallel and apart from each other at a predetermined distance,

wherein light diffused in one of a circular conical plane-like and a semi-circular conical plane like having the center axis with a line parallel to the ridges is transmitted in a direction for light distribution when light is incident on the ridges of each of the structures.

3. A light distribution control device according to claim 2, wherein the plurality of ridges are formed on both of the surfaces of the each structure.

4. A light distribution control device according to claim 2, wherein:

each of the structures has either a long and thin plate shape or a long and thin film shape; and

a number of ridges are formed along a direction crossing a longitudinal direction of the each structures.

5. A light distribution control device according to claim 4, wherein the each structure has the cross section orthogonal to the longitudinal direction thereof which has either a bent shape or a V-shape.

6. A light distribution control device according to claim 2, further comprising an adjusting mechanism for varying the angle of each of the structures relative to the arraying direction of the plurality of structures.

7. A light distribution control device according to claim 2, wherein the light distribution control device is installed at the windows, through which outside light enters and the plurality of structures are arrayed along the surface of the windows to introduce light diffused by the ridges of the each structure into a room.

8. A light distribution control device according to claim 2, wherein the light distribution control device is installed in a place which is located above a region shaded by a building and on which outside light enters/reaches, to introduce light diffused by the ridges of the each structure to the region which would be shaded by the building.

9. A light distribution control device according to claim 2, wherein the light distribution control device is installed on at least one of the ceiling portion and the wall portion of a greenhouse or in a vicinity thereof to introduce light diffused by the ridges of the each structures to the interior of the greenhouse.

10. A greenhouse, comprising:

the light distribution control device according to claim 2 installed on at least one of the ceiling portion and the wall portion thereof or a vicinity thereof.

11. A greenhouse according to claim 10, wherein at least one of the ceiling portion and the wall portion is formed by a light distribution panel having the light distribution control device interposed between two transparent plates with a double structure.