Phosphor, manufacturing method thereof, and light-emitting device using the phosphor

Patent metadata

Field	Value
Publication number	US-9954146-B2
Application number	US-201514850168-A
Country	US
Kind code	B2
Filing date	Sep 10, 2015
Priority date	Mar 15, 2013
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

The present invention provides a red-light emitting phosphor having high luminous efficacy and also a manufacturing method thereof. The phosphor is a red-light emitting phosphor mainly comprising potassium fluorosilicate and having a basic surface composition represented by the formula (A): K a SiF b . The disclosed phosphor is characterized by being activated by manganese and also characterized in that the amount of manganese on the surface is not more than 0.2 mol % based on the total amount of all the elements on the surface. This phosphor can be manufactured by washing with a weak acid a product obtained by placing a silicon source to react in contact with a reaction solution containing potassium permanganate.

First claim

The invention claimed is:

1. A red-light emitting phosphor particle, comprising potassium fluorosilicate and having a composition represented by the formula (A) at a surface thereof:
K a SiF b   (A),

where 1.5≤a≤2.5 and 5.5≤b≤6.5,
wherein the red-light emitting phosphor particle is activated by manganese,
the composition as a whole is represented by the formula (B):
K c (Si 1-x ,Mn x )F d   (B),

where 1.5≤c≤2.5, 5.5≤d≤6.5 and 0<x≤0.06
a total of an amount of manganese present on a superficial face of the red-light emitting phosphor particle and an area under the superficial face reachable by the X-ray photoelectron spectroscopy with the following conditions is not more than 0.2 mol % based on the total amount of all elements on the surface:
X-ray source: AlKα line,
power: 40 W,
measuring area: Φ 200 μm,
pass energy:
wide scan: 187.85 eV (1.60 eV/step)
narrow scan: 58.70 eV (0.125 ev/step),

charge neutralization gun: e − in use with Art, and
takeoff angle: 45°,

the amounts of oxygen and fluorine in the red-light emitting phosphor particle satisfy [oxygen content]/[(fluorine content)+(oxygen content)]<0.05, and
the red-light emitting phosphor particle has an internal quantum efficiency η′ of 60% or more, where the internal quantum efficiency if is calculated by the formula (II):

internal
⁢

⁢
quantum
⁢

⁢

efficiency
⁡

(

η
′

)

=

(

∫

λ
·

[

P
⁡

(
λ
)

]

⁢
d
⁢

⁢
λ

)

(

∫

λ
·

[

E
⁡

(
λ
)

-

R
⁡

(
λ
)

]

⁢
d
⁢

⁢
λ

)

(
II
)

wherein
E(λ) is the whole spectrum of light emitted by an excitation light source onto the red-light emitting phosphor particle in terms of number of photons,
R(λ) is the spectrum of light emitted by the excitation light source and reflected by the red-light emitting phosphor particle in terms of the number of photons, and
P(λ) is the emission spectrum of the red-light emitting phosphor particle in terms of the number of photons.

2. The red-light emitting phosphor particle according to claim 1 , having a light absorptivity of 10% or less in the wavelength range of from 600 nm to 650 nm.

3. A method for manufacturing the red-light emitting phosphor particle according to claim 2 , comprising:
immersing a silicon source in a reaction solution comprising potassium permanganate and hydrogen fluoride such that the silicon source is reacted with the reaction solution and that a crystal is formed;
separating the crystal from the reaction solution;
washing the crystal with a weak acid after the separating; and
subjecting the crystal to rinse treatment after the washing.

4. A light-emitting device, comprising:
a light-emitting element radiating light in the wavelength range of from 440 nm to 470 nm; and
a phosphor layer comprising the red-light emitting phosphor particle according to claim 2 .

5. The light-emitting device according to claim 4 , wherein the phosphor layer further comprises an orange- or red-light emitting phosphor particle.

6. A method for manufacturing the red-light emitting phosphor particle according to claim 1 , comprising:
immersing a silicon source in a reaction solution comprising potassium permanganate and hydrogen fluoride such that the silicon source is reacted with the reaction solution and that a crystal is formed;
separating the crystal from the reaction solution;
washing the crystal with a weak acid after the separating; and
subjecting the crystal to rinse treatment after the washing,
wherein the reaction solution comprises potassium permanganate and hydrogen fluoride in a molar ratio of from 1/200 to 1/40.

7. The method according to claim 6 , wherein, in the immersing, the silicon source is immersed in the reaction solution for 20 minutes to 80 minutes.

8. The method according to claim 6 , wherein the weak acid is at least one selected from the group consisting of hydrofluoric acid, acetic acid, carbonic acid and phosphoric acid.

9. The method according to claim 6 , wherein the silicon source is at least one selected from the group consisting of single crystal silicon, polycrystal silicon, amorphous silicon, crystalline silicon dioxide and amorphous

Assignees

• Toshiba Kk
• Toshiba Materials Co Ltd
• Toshiba Materials Co Ltd

Inventors

• Hiramatsu Ryosuke
• Albessard Keiko
• Matsuda Naotoshi
• Kato Masahiro

Classifications

• H10W90/722

  between stacked chips · CPC title

• H10W74/00

  Encapsulations, e.g. protective coatings · CPC title

• H10W72/884

  Die-attach connectors and bond wires · CPC title

• C09K11/617

  Silicates · CPC title

• H01L2924/00012

  Electricity · mapped topic