Light emitting device and plant cultivation method

Patent metadata

Field	Value
Publication number	US-10455773-B2
Application number	US-201715634401-A
Country	US
Kind code	B2
Filing date	Jun 27, 2017
Priority date	Jun 29, 2016
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

Provided is a light emitting device that includes a light emitting element having a light emission peak wavelength ranging from 380 nm to 490 nm, and a fluorescent material excited by light from the light emitting element and emitting light having at a light emission peak wavelength ranging from 580 nm or more to less than 680 nm. The light emitting device emits light having a ratio R/B of a photon flux density R to a photon flux density B ranging from 2.0 to 4.0 and a ratio R/FR of the photon flux density R to a photon flux density FR ranging from 0.7 to 13.0, the photon flux density R being in a wavelength range of 620 nm or more and less than 700 nm, the photon flux density B being in a wavelength range of 380 nm or more and 490 nm or less, and the photon flux density FR being in a wavelength range of 700 nm or more and 780 nm or less.

First claim

What is claimed is:

1. A light emitting device comprising:
a light emitting element having a light emission peak wavelength in a range of 380 nm or more and 490 nm or less; and
a first fluorescent material that is excited by light from the light emitting element and emits light having at least one light emission peak wavelength in a range of 580 nm or more and less than 680 nm, wherein the first fluorescent material contains:
a fluorogermanate fluorescent material that is activated by Mn 4+ , and
a fluorescent material that has a composition containing at least one element selected from Sr and Ca, and Al, and contains silicon nitride that is activated by Eu 2+ ; and

a second fluorescent material that is excited by light from the light emitting element and emits light having at least one light emission peak wavelength in a range of 680 nm or more and 800 nm or less, wherein
the light emitting device emits light having a ratio RB of a photon flux density R to a photon flux density B within a range of 2.0 or more and 4.0 or less, and a ratio R/FR of the photon flux density R to a photon flux density FR within a range of 0.7 or more and 2.0 or less, wherein
the photon flux density R is in a wavelength range of 620 nm or more and less than 700 nm,
the photon flux density B is in a wavelength range of 380 nm or more and 490 nm or less, and
the photon flux density FR is in a wavelength range of 700 nm or more and 780 nm or less.

2. The light emitting device according to claim 1 , wherein
the second fluorescent material contains a first element Ln containing at least one element selected from the group consisting of rare earth elements excluding Ce, a second element M containing at least one element selected from the group consisting of Al, Ga and In, Ce, and Cr, and has a composition of an aluminate fluorescent material, and
when a molar ratio of the second element M is taken as 5, a molar ratio of Ce is a product of a value of a parameter x and 3, and a molar ratio of Cr is a product of a value of a parameter y and 3, the value of the parameter x being in a range of exceeding 0.0002 and less than 0.50, and the value of the parameter y being in a range of exceeding 0.0001 and less than 0.05.

3. The light emitting device according to claim 1 , wherein the second fluorescent material has the composition represented by the following formula (I):
(Ln 1−x−y Ce x Cr y ) 3 M 5 O 12   (I)

wherein Ln is at least one rare earth element selected from the group consisting of rare earth elements excluding Ce,
M is at least one element selected from the group consisting of Al, Ga, and In, and
x and y are numbers satisfying 0.0002<x<0.50 and 0.0001<y<0.05.

4. The light emitting device according to claim 1 ,
wherein
a mass ratio between the fluorogermanate fluorescent material and the fluorescent material containing silicon nitride (fluorogermanate fluorescent material:fluorescent material containing silicon nitride) is in a range of 50:50 or more and 99:1 or less.

5. The light emitting device according to claim 1 , the light emitting device being used in plant cultivation.

6. A plant cultivation method comprising irradiating plants with light emitted from the light emitting device according to claim 1 .

Assignees

• Nichia Corp

Inventors

• Amiya Mika
• Fujio Kazushige
• Suzuki Tomokazu

Classifications

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W72/884

  Die-attach connectors and bond wires · CPC title

• A01G31/00

  Soilless cultivation, e.g. hydroponics (growth substrates therefor A01G24/00; cultivation of seaweed A01G33/00) · CPC title

• A01G7/045 Primary

  with electric lighting · CPC title

• H01L2224/48247

  Electricity · mapped topic