Light emitting device and plant cultivation method

Patent metadata

Field	Value
Publication number	US-10952382-B2
Application number	US-201916572524-A
Country	US
Kind code	B2
Filing date	Sep 16, 2019
Priority date	Jun 29, 2016
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

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, the second fluorescent material comprising:
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

having a composition of an aluminate fluorescent material,
wherein a molar ratio of Ce is a product of a parameter x and 3, and a molar ratio of Cr is a product of a parameter y and 3, the parameter x is in a range of 0.0005 or more and less than 0.50, and the parameter y is in a range of 0.014 or more and less than 0.05 when a molar ratio of the second element M is taken as 5 in the composition of the aluminate fluorescent material, and wherein
the light emitting device emits light having a ratio R/B 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 first element Ln contained in the second fluorescent material is at least one element selected from the group consisting of Y, Gd, Lu, La, Tb and Pr.

3. The light emitting device according to claim 1 , wherein the second element M contained in the second fluorescent material is Al or Ga.

4. The light emitting device according to claim 1 , wherein the parameter x of the second fluorescent material is in a range of 0.001 or more and 0.350 or less.

5. The light emitting device according to claim 1 , wherein the parameter y of the second fluorescent material is in a range of 0.014 or more and 0.026 or less.

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

wherein Ln is at least one 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 satisfy 0.0005≤x<0.50, and 0.014≤y<0.05.

7. The light emitting device according to claim 6 , wherein Ln is at least one element selected from the group consisting of Y, Gd, Lu, La, Tb and Pr in the formula (1).

8. The light emitting device according to claim 6 , wherein M is Al or Ga in the formula (1).

9. The light emitting device according to claim 6 , wherein x satisfies 0.001≤x≤0.350 in the formula (1).

10. The light emitting device according to claim 6 , wherein y satisfies 0.014≤y≤0.026 in the formula (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

• H10H20/8513

  having two or more wavelength conversion materials · CPC title

• A01G22/60

  Flowers; Ornamental plants · CPC title

• A01G22/15

  Leaf crops, e.g. lettuce or spinach · CPC title