Illuminating device and plant growth regulation method

Patent metadata

Field	Value
Publication number	US-9927095-B2
Application number	US-201314059060-A
Country	US
Kind code	B2
Filing date	Oct 21, 2013
Priority date	Apr 22, 2011
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

The present invention provides an illuminating device that makes it possible to reduce the number of members for regulating a polarization state and can irradiate light having natural color shades without decreasing energy efficiency of light irradiation, and a plant growth regulation method using the illuminating device. The illuminating device of the present invention includes a light-emitting light source and a polarization state regulation member that regulates a polarization state of the light-emitting light source, in which the polarization state of a wavelength region of a portion of emission wavelengths is changed to circular polarization, and a degree of circular polarization of light in a wavelength band for regulation among the light rays to be irradiated is 0.3 or higher. In a preferable embodiment, a width of at least one wavelength band for regulation of the polarization state regulation member is from 60 nm to 250 nm.

First claim

What is claimed is:

1. An illuminating device comprising:
a light-emitting light source; and
a polarization state regulation member that regulates a polarization state of the light-emitting light source, wherein a width of at least one wavelength band for regulation of the polarization state regulation member is from 60 nm to 250 nm,
wherein:

the polarization state of a wavelength region of 20% to 80% of emission wavelengths is changed to circular polarization,
a degree of circular polarization of light in a wavelength band for regulation among the light rays to be irradiated is 0.3 or higher, the degree of circular polarization being defined as |I R −I L |/|I R +I L |, wherein I R represents an intensity of a right circular polarization component of light, and I L represents an intensity of a left circular polarization component, and
the polarization state regulation member is one of a circularly polarized light-reflecting plate and a circular polarizing plate including a linear polarizing plate and a λ/4 wave plate.

2. The illuminating device according to claim 1 ,
wherein the polarization state regulation member is the circular polarizing plate including a linear polarizing plate and a λ/4 wave plate.

3. The illuminating device according to claim 1 ,
wherein the polarization state regulation member is the circularly polarized light-reflecting plate.

4. The illuminating device according to claim 3 ,
wherein the circularly polarized light-reflecting plate has a cholesteric liquid crystal structure.

5. The illuminating device according to claim 4 ,
wherein the circularly polarized light-reflecting plate has two or more wavelength regions for regulating polarization.

6. The illuminating device according to claim 4 , further comprising one of a diffuser plate and a retardation plate between the light-emitting light source and the circularly polarized light-reflecting plate.

7. The illuminating device according to claim 3 ,
wherein the circularly polarized light-reflecting plate is composed of a linearly polarized light-reflecting plate and a λ/4 wave plate.

8. The illuminating device according to claim 7 , further comprising one of a diffuser plate and a retardation plate between the light-emitting light source and the circularly polarized light-reflecting plate.

9. The illuminating device according to claim 3 , further comprising one of a diffuser plate and a retardation plate between the light-emitting light source and the circularly polarized light-reflecting plate.

10. The illuminating device according to claim 9 ,
wherein a phase difference in an in-plane direction of the retardation plate is 300 nm or more when being measured under a wavelength condition of 550 nm.

11. A plant growth regulation method that uses the illuminating device according to claim 1 as an irradiation light source.

Assignees

• Fujifilm Corp

Inventors

• Ichihashi Mitsuyoshi
• Usami Yoshihisa
• Majima Wataru

Classifications

• A01G7/045

  with electric lighting · CPC title

• F21V9/14 Primary

  for producing polarised light · CPC title

• Y02P60/146

  Cross-Sectional Technologies · mapped topic

• G02B5/3083

  Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001) · CPC title

• A01G9/249

  Lighting means (with special arrangements for promoting growth A01G7/045) · CPC title