US 12,648,271 B2Granted

Light emitting device, headlight, and vehicle comprising same

AssigneeNichia Corporation

InventorsHaruka Hino, Yukiko Sano

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Abstract

Provided are a light emitting device capable of reducing glare, a headlight, and a vehicle including the same. The light emitting device comprises: a light emitting element having a light emission peak wavelength in a range of 400 nm or more and 490 nm or less; and a wavelength conversion member including a first fluorescent material having a light emission peak wavelength in a range of 480 nm or more and less than 580 nm and a second fluorescent material having a light emission peak wavelength in a range of 580 nm or more and 680 nm or less and having a composition different from that of the first fluorescent material, wherein the light emitting device emits light having a first luminance ratio Ls/L that is 0.9 or less, where Ls/L is a ratio of a first effective radiance Ls of the light emitted by the light emitting device in consideration of a spectral luminous efficiency curve for photopic vision of humans specified by the CIE (Commission Internationale de l'Eclairage) and S-cone spectral sensitivity of humans, to a luminance L of the light emitted by the light emitting device in consideration of the spectral luminous efficiency curve for photopic vision of humans.

Claims34

Dependent claims

A light emitting device, comprising:

a light emitting element having a light emission peak wavelength in a range of 400 nm or more and 490 nm or less;
and
a wavelength conversion member including a first fluorescent material having a light emission peak wavelength in a range of 480 nm or more and less than 580 nm and a second fluorescent material having a light emission peak wavelength in a range of 580 nm or more and 680 nm or less and having a composition different from that of the first fluorescent material,
wherein the light emitting device emits light having a first luminance ratio Ls/L, as derived from the following formula (1), of 0.9 or less,
wherein the first luminance ratio Ls/L is a ratio of a first effective radiance Ls of light emitted by the light emitting device in a range of 380 nm or more and 780 nm or less in consideration of a spectral luminous efficiency curve for photopic vision of humans specified by the CIE (Commission Internationale de l'Eclairage) and S-cone spectral sensitivity of humans, to a luminance L of the light emitted by the light emitting device in a range of 380 nm or more and 780 nm or less in consideration of spectral luminous efficiency curve for photopic vision of humans:
Ls
/
L
=
∫
380
780
S
⁡
(
λ
)
⁢
{
1.26
×
Gs
⁡
(
λ
)
+
V
⁡
(
λ
)
}
⁢
d
⁢
λ
2.3
∫
380
780
S
⁡
(
λ
)
×
V
⁡
(
λ
)
⁢
d
⁢
λ
(
1
)
wherein S (λ) represents a spectral radiance of light emitted by the light emitting device, V (λ) represents a spectral luminous efficiency curve for photopic vision of humans specified by the CIE (Commission Internationale de l'Eclairage), and Gs (λ) represents an S-cone spectral sensitivity of humans in a wavelength λ range of 380 nm or more and 550 nm or less.

57 more elements

A light emitting device, comprising:

a light emitting element having a light emission peak wavelength in a range of 400 nm or more and 490 nm or less;
and
a wavelength conversion member including a first fluorescent material having a light emission peak wavelength in a range of 480 nm or more and less than 580 nm and a second fluorescent material having a light emission peak wavelength in a range of 580 nm or more and 680 nm or less and having a composition different from that of the first fluorescent material,
the light emitting device emitting light having a second luminance ratio B/A, as derived from the following formula (2), of 0.104 or less,
wherein the second luminance ratio B/A is a ratio of a second effective radiance B of light emitted by the light emitting device in a range of 300 nm or more and 800 nm or less in consideration of a scattering intensity curve for wavelengths when a scattering intensity of Rayleigh scattering at a wavelength of 300 nm is 1, to a radiance A of the light emitted by the light emitting device in a range of 300 nm or more and 800 nm or less:
B
/
A
=
∫
300
800
Dc
⁡
(
λ
)
×
S
⁡
(
λ
)
⁢
d
⁢
λ
∫
300
800
S
⁡
(
λ
)
⁢
d
⁢
λ
(
2
)
wherein S (λ) represents a spectral radiance of light emitted by the light emitting device and Dc (λ) represents a scattering intensity curve for wavelengths when a scattering intensity of Rayleigh scattering at a wavelength of 300 nm is 1 in Rayleigh scattering.

40 more elements

Dependencies are inferred from the claim text.