Light-emitting device with two green light-emitting elements with different peak wavelengths and backlight including light-emitting device

• US 10,274,667 B2
• Filed: 01/17/2017
• Issued: 04/30/2019
• Est. Priority Date: 01/18/2016
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Akagawa, Seitaro, Morikawa, Takeshi, Achi, Yusaku, Nishigaki, Kentaro
• Primary Examiner(s): Mai, Anh T
• Assistant Examiner(s): Chiang, Michael
• Application Number:
  US15/407,377
• Publication Number:
  US 20170205565A1
• Time in Patent Office: 833 Days
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02B 6/0083 Details of electrical connections of light sources to drivers, circuit boards, or the like
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/105 the devices being of a type provided for in group H01L27/00
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 33/50 Wavelength conversion elements

Abstract

A light-emitting device includes: one or more first light-emitting elements each having a peak wavelength in a range from 430 nm to less than 490 nm; a second light-emitting element having a peak wavelength Y in a range from 490 nm to less than a wavelength X; a third light-emitting element having a peak wavelength Z in a range from more than the wavelength X to 570 nm; and a phosphor or a fourth light-emitting element having a peak wavelength in a range from 580 nm to 680 nm. At least one of the second and third light-emitting elements is connected to at least one of the first light-emitting elements in series. The wavelength X is in a range from more than 490 nm to less than 570 nm with an absolute value of difference between |X−Y| and |X−Z| being 10 nm or less.

Claims

1. A light-emitting device comprising:

at least two first light-emitting elements each having a peak wavelength in a range from 430 nm to less than 490 nm;

at least one second light-emitting element having a peak wavelength Y in a range from 490 nm to less than a wavelength X;

at least one third light-emitting element having a peak wavelength Z in a range from more than the wavelength X to 570 nm; and

a phosphor having a composition represented by A₂MF₆;

Mn⁴⁺, wherein A is at least one selected from the group consisting of K, Li, Na, Rb, Cs, and NH.sub.4.sup.+, and M is at least one element selected from the group consisting of Group IV elements and Group XIV elements,

wherein at least one of the second light-emitting element and the third light-emitting element is connected to at least one of the first light-emitting elements in series,

the wavelength X is in a range from more than 490 nm to less than 570 nm with an absolute value of difference between |X−

Y| and |X−

Z| being 10 nm or less,

a number of the first light-emitting elements is equal to a total number of the second light-emitting element and the third light-emitting element, and

a ratio of a total light output of the second light-emitting element and the third light-emitting element to a total light output of the first light-emitting elements is in a range from 0.3 to 0.7 about 0.3 or more and about 0.7 or less.

2. The light-emitting device according to claim 1, further comprising

the number of the one or more first light-emitting elements is two, wherein

the first light-emitting elements, the second light-emitting element, and the third light-emitting element are arranged in a two-dimensional array,

the first light-emitting elements are arranged diagonally with respect to each other along a first diagonal line connecting centers of the first light-emitting elements, and

the second light-emitting element and the third light-emitting element are arranged diagonally with respect to each other along a second diagonal line other than the first diagonal line.

3. The light-emitting device according to claim 1, wherein

the wavelength X is in a range from 515 nm to 535 nm.

4. The light-emitting device according to claim 1, further comprising

a support on which the first light-emitting elements, the second light-emitting element, and the third light-emitting element are disposed.

5. The light-emitting device according to claim 1, wherein

the phosphor is contained in a light-transmissive member covering the first light-emitting elements, the second light-emitting element, and the third light-emitting element.

6. A backlight comprising:

the light-emitting device according to claim 1; and

a light guide plate having a lateral surface including an incident portion of light, the light guide plate being arranged with respect to the light-emitting device so that the incident portion faces a light extracting surface of the light-emitting device.

7. The light-emitting device according to claim 1, wherein

the number of the first light-emitting elements is 2, and the total number of the second-light emitting element and the third light-emitting element is 2.