Light guiding film and plant growing method using the light guiding film

• US 8,615,925 B2
• Filed: 01/24/2011
• Issued: 12/31/2013
• Est. Priority Date: 02/16/2010
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Usami, Yoshihisa
• Primary Examiner(s): Swiatek, Rob
• Assistant Examiner(s): EVANS, EBONY E
• Application Number:
  US13/011,947
• Publication Number:
  US 20110197503A1
• Time in Patent Office: 1,072 Days
• Field of Search: 47/10.1 R, 47/14, 47/17, 47/291, 47/323, 47/581.R, 47/581.S, 47D/IG.9, 428/411.1, 430/269, 430/321, 430/644, 362/84, 362/551, 359/326, 359/332, 385129-132
• US Class Current: 47/58.1LS
• CPC Class Codes: A01G 7/045 with electric lighting
• CPC Class Codes: G02B 6/0003 the light guides being doped with fluorescent agents
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: Y02P 60/14 Measures for saving energy, e.g. in green houses

Abstract

A light guiding film including: a light entrance portion which allows incident light from a light source to enter; a wavelength converting portion which absorbs the incident light and converts the wavelength of the incident light to a wavelength utilizable for growth of a plant; and a light exit portion which allows the light with the converted wavelength to exit.

Claims

1. A light guiding film comprising:

a light entrance portion which allows incident light from a light source to enter;

a wavelength converting portion which absorbs the incident light and converts the wavelength of the incident light to a wavelength utilizable for growth of a plant; and

a light exit portion which allows the light with the converted wavelength to exit,

wherein the light entrance portion and the light exit portion are located at opposite sides of the light guiding film in a longitudinal direction of the light guiding film,

wherein the light entrance portion includes a light entrance surface,

wherein the wavelength converting portion is provided on a surface of the light entrance portion on a side opposite to the light entrance surface in a direction perpendicular to the longitudinal direction, and

wherein a refractive index of the wavelength converting portion is higher than a refractive index of the light entrance portion.

2. The light guiding film according to claim 1, wherein the relationship λ

₁<

λ

₂ is satisfied, where λ

₁ (nm) denotes a peak wavelength of the light absorbed by the wavelength converting portion, and λ

₂ (nm) denotes a peak wavelength of the light with the converted wavelength.

3. The light guiding film according to claim 2, wherein λ

₁ is in the range of 300 nm to 700 nm, and λ

₂ is in the range of 400 nm to 1,000 nm.

4. The light guiding film according to claim 1, wherein the wavelength converting portion includes a fluorescent material.

5. The light guiding film according to claim 4, wherein the fluorescent material contains a perylene compound.

6. The light guiding film according to claim 1, further comprising a light guiding portion which guides the light with the converted wavelength, situated between the light entrance portion and the light exit portion.

7. The light guiding film according to claim 6, further comprising a reflective layer formed on a surface of the light entrance portion with respect to a film thickness direction or on surfaces of the light entrance portion and the light guiding portion with respect to the film thickness direction.

8. The light guiding film according to claim 1, wherein the light entrance portion has a refractive index of 1.05 to 1.8.

9. The light guiding film according to claim 1, wherein the wavelength converting portion has a refractive index of 1.5 or greater.

10. The light guiding film according to claim 1, wherein the difference in refractive index between the wavelength converting portion and the light entrance portion is in the range of 0.01 to 2.0.

11. The light guiding film according to claim 1, wherein the light exit portion has minute concave and convex portions at at least part of a surface thereof.

12. A plant growing method comprising:

growing a plant using a light guiding film,

wherein the light guiding film comprises;

a light entrance portion which allows incident light from a light source to enter;

a wavelength converting portion which absorbs the incident light and converts the wavelength of the incident light to a wavelength utilizable for growth of a plant; and

a light exit portion which allows the light with the converted wavelength to exit,

wherein the light entrance portion and the light exit portion are located at opposite sides of the light guiding film in a longitudinal direction of the light guiding film,

wherein the light entrance portion includes a light entrance surface,

wherein the wavelength converting portion is provided on a surface of the light entrance portion on a side opposite to the light entrance surface in a direction perpendicular to the longitudinal direction,

wherein a refractive index of the wavelength converting portion is higher than a refractive index of the light entrance portion, and

wherein the wavelength of the light which has entered from the light entrance portion of the light guiding film is converted to a wavelength utilizable for growth of the plant, and the light exit portion of the light guiding film is placed so as to allow the light to exit from the light exit portion to a place for the growth of the plant.

13. The plant growing method according to claim 12, wherein the plant is algae including microalgae.

14. The plant growing method according to claim 12, wherein the light entrance portion is located above a water surface and the light exit portion is located under the water surface.

15. The plant growing method according to claim 12, wherein the wavelength converting portion contains a fluorescent material, and

wherein the fluorescent material is perylene red or perylene orange.