Lighting device for growing plant

• US 9,030,089 B2
• Filed: 11/14/2012
• Issued: 05/12/2015
• Est. Priority Date: 11/18/2011
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Komada, Satoshi, Konishi, Katsuyuki
• Primary Examiner(s): Breval, Elmito
• Application Number:
  US13/676,978
• Publication Number:
  US 20130127329A1
• Time in Patent Office: 909 Days
• US Class Current: 313/498
• CPC Class Codes: A01G 7/045 with electric lighting
• CPC Class Codes: F21V 9/02 for simulating daylight F21V9/04, F21V9/06 take precedence
• CPC Class Codes: F21V 9/30 Elements containing photoluminescent material distinct from or spaced from the light source shades F21V1/17; globes, bowls or cover glasses F21V3/08, F21V3/12; refractors F21V5/10; reflectors F21V7/26, F21V7/30; elements with provision for controlling the spectral properties or intensity F21V9/40
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: Y02P 60/14 Measures for saving energy, e.g. in green houses

Abstract

A lighting device for growing a plant includes: not less than two sorts of semiconductor light-emitting element, each having a peak emission wavelength in a range of 380 nm to 500 nm, the not less than two sorts of semiconductor light-emitting element being different from each other in peak emission wavelength by not less than 5 nm; and a red fluorescent material which (i) is excited by light of at least one of the not less than two sorts of semiconductor light-emitting element and (ii) has a peak emission wavelength in a range of 600 nm to 780 nm.

Claims

1. A lighting device for growing a plant comprising:

a first semiconductor light-emitting element, a second semiconductor light-emitting element and a third semiconductor light-emitting element each having a peak emission wavelength in a range of 380 nm to 500 nm, the first semiconductor light-emitting element, the second semiconductor light-emitting element and the third semiconductor light-emitting element being different from each other in peak emission wavelength by not less than 5 nm; and

a red fluorescent material which (i) is excited by light of at least one of the first semiconductor light-emitting element, the second semiconductor light-emitting element and the third semiconductor light-emitting element and (ii) has a peak emission wavelength in a range of 600 nm to 780 nm,

the first semiconductor light-emitting element, the second semiconductor light-emitting element and the third semiconductor light-emitting element being connected in this order so as to constitute a single unit, (i) two or more of the units being connected to each other in series to constitute a semiconductor light-emitting element group, (ii) two or more of the semiconductor light-emitting element groups being connected to each other in parallel, and (iii) the two or more of the semiconductor light-emitting element groups being identical with each other in the number of the first semiconductor light-emitting elements, the number of the second semiconductor light-emitting elements and the number of the third semiconductor light-emitting elements,

the first semiconductor light-emitting element, the second semiconductor light-emitting element and the third semiconductor light-emitting element being controlled together by a single power supply circuit.

2. The lighting device as set forth in claim 1, wherein:

the first semiconductor light-emitting element has a peak wavelength in a range of ±

40 nm of a peak value in a Soret band of an absorption spectrum of chlorophyll a;

the second semiconductor light-emitting element has a peak wavelength in a range of within ±

40 nm of a peak value in a Soret band of an absorption spectrum of chlorophyll b; and

the third semiconductor light-emitting element has a peak wavelength in a range of within ±

40 nm of a peak value in a Soret band of an absorption spectrum of chlorophyll c.

3. The lighting device as set forth in claim 1, wherein:

the red fluorescent material is constituted by not less than two sorts of red fluorescent material, which are different from each other in peak emission wavelength.

4. The lighting device as set forth in claim 1, wherein:

the red fluorescent material is constituted by a bivalent europium-activated nitride fluorescent material represented by the following general formula (A);

(MIV_1-cEu_c)MVSiN₃ 

 

(A)

(where;

MIV represents at least one element selected from the group consisting of Mg, Ca, Sr, and Ba;

MV represents at least one element selected from the group consisting of Al, Ga, In, Sc, Y, La, Gd, and Lu; and

0.001≦

c≦

0.15).

5. The lighting device as set forth in claim 4, wherein:

the red fluorescent material is constituted by not less than two sorts of red fluorescent material, which are different from each other in peak emission wavelength; and

the not less than two sorts of red fluorescent material (i) are bivalent europium-activated nitride fluorescent materials, each being represented by the general formula (A) (where MIV represents a combination of Mg, Ca, and Sr), and (ii) are different from each other in an atomic composition ratio between Mg, Ca, and Sr of MIV.

6. The lighting device as set forth in claim 4, wherein:

the red fluorescent material is constituted by not less than two sorts of red fluorescent material, which are different from each other in peak emission wavelength; and

the not less than two sorts of red fluorescent material (i) are bivalent europium-activated nitride fluorescent materials, each being represented by the general formula (A), and (ii) are different from each other in an atomic composition ratio of Eu with respect to that of MIV.

7. The lighting device as set forth in claim 1, further comprising:

a green fluorescent material for emitting green light having a wavelength which is more than 500 nm but less than 600 nm.

8. The lighting device as set forth in claim 1, further comprising:

a green fluorescent material which (i) is excited by light of at least one of the first semiconductor light-emitting element, the second semiconductor light-emitting element and the third semiconductor light-emitting element, and (ii) has a peak emission wavelength in a range of 480 nm to 600 nm.

9. The lighting device as set forth in claim 8, wherein:

the green fluorescent material is (Lu_1-xCe_x)₃Al₅O₁₃ (0.001≦

x≦

0.05).

10. The lighting device as set forth in claim 1, wherein:

the first semiconductor light-emitting element, the second semiconductor light-emitting element and the third semiconductor light-emitting element are arranged such that, among the not less than two sorts of semiconductor light-emitting element, semiconductor light-emitting elements which are identical with each other in peak emission wavelength are not placed next to each other.

11. The lighting device as set forth in claim 1, wherein:

each of the not less than two sorts of semiconductor light-emitting element is constituted by a nitride semiconductor.

13. The lighting device as set forth in claim 1, wherein:

the first semiconductor light-emitting element, the second semiconductor light-emitting element and the third semiconductor light-emitting element are configured so as to have peak emission wavelengths in a range of ±

40 nm of a peak absorption wavelength of a chlorophyll.

12. A blue-light lighting device comprising:

a first semiconductor light-emitting element, a second semiconductor light-emitting element and a third semiconductor light-emitting element each having a peak emission wavelength in a range of 380 nm to 500 nm, which range is a range of an absorption wavelength of a photosynthetic pigment, the first semiconductor light-emitting element, the second semiconductor light-emitting element and the third semiconductor light-emitting element being different from each other in peak emission wavelength by not less than 5 nm,

the first semiconductor light-emitting element, the second semiconductor light-emitting element and the third semiconductor light-emitting element being connected in this order so as to constitute a single unit, (i) two or more of the units being connected to each other in series to constitute a semiconductor light-emitting element group, (ii) two or more of the semiconductor light-emitting element groups being connected to each other in parallel, and (iii) the two or more of the semiconductor light-emitting element groups being identical with each other in the number of the first semiconductor light-emitting elements, the number of the second semiconductor light-emitting elements and the number of the third semiconductor light-emitting elements,

the first semiconductor light-emitting element, the second semiconductor light-emitting element and the third semiconductor light-emitting element being controlled together by a single power supply circuit.