US 11,757,070 B2
Light emitting device with Ce-activated aluminate fluorescent material
Mika Amiya, Naruto (JP); and Shoji Hosokawa, Tokushima (JP)
Assigned to NICHIA CORPORATION, Anan (JP)
Filed by NICHIA CORPORATION, Anan (JP)
Filed on Dec. 31, 2020, as Appl. No. 17/139,655.
Application 17/139,655 is a continuation of application No. 16/227,791, filed on Dec. 20, 2018, granted, now 10,910,526.
Claims priority of application No. 2017-250037 (JP), filed on Dec. 26, 2017.
Prior Publication US 2021/0126169 A1, Apr. 29, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. H01L 33/50 (2010.01); H01L 33/32 (2010.01); H01L 25/075 (2006.01)
CPC H01L 33/504 (2013.01) [H01L 25/0753 (2013.01); H01L 33/32 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A light emitting device comprising:
a first light emitting element having a light emission peak wavelength within a range of 400 nm or more and 490 nm or less,
a second light emitting element having a light emission peak wavelength different from the first light emitting element within a range of 450 nm or more and 490 nm or less,
a first fluorescent material that is excited by at least one of the first light emitting element and the second light emitting element and emits light having a light emission peak wavelength within a range of 500 nm or more and 540 nm or less, and
a second fluorescent material that is excited by at least one of the first light emitting element and the second light emitting element and emits light having a light emission peak wavelength within a range of 600 nm or more and 680 nm or less,
wherein the first fluorescent material is a Ce-activated aluminate fluorescent material containing Lu, Al, and Ga, and optionally at least one element selected from rare earth elements other than Lu, and
wherein a minimum light emission intensity of an emission spectrum of the light emitting device in the range of 470 nm or more and 500 nm or less is within the range of 0.7 or more and 1.1 or less with respect to a light emission intensity of the emission peak wavelength of the second light emitting element,
wherein the first fluorescent material has a composition represented by the following formula (I):
(Lu1-x Lnx)3(Al1-yGay)5O12:Ce  (I)
wherein Ln is at least one rare earth element selected from the group consisting of Y, Gd, and Tb; and x and y are numbers respectively satisfying 0≤x≤0.7 and 0<y≤0.5.