Illumination method and light-emitting device
First Claim
Patent Images
1. A light-emitting device comprising at least a semiconductor light-emitting element as a light-emitting element, whereinlight emitted from the light-emitting device includes, in a main radiant direction thereof, light whose distance DuvSSL from a black-body radiation locus as defined by ANSI C78.377 satisfies −
- 0.0350≦
DuvSSL<
0, andif a spectral power distribution of light emitted from the light-emitting device in the radiant direction is denoted by φ
SSL (λ
), a spectral power distribution of a reference light that is selected according to a correlated color temperature TSSL (K) of the light emitted from the light-emitting device in the radiant direction is denoted by φ
ref (λ
), tristimulus values of the light emitted from the light-emitting device in the radiant direction are denoted by (XSSL, YSSL, ZSSL), and tristimulus values of the reference light that is selected according to the correlated color temperature TSSL (K) of the light emitted from the light-emitting device in the radiant direction are denoted by (Xref, Yref, Zref), andif a normalized spectral power distribution SSSL (λ
) of light emitted from the light-emitting device in the radiant direction, a normalized spectral power distribution Sref (λ
) of a reference light that is selected according to the correlated color temperature TSSL (K) of the light emitted from the light-emitting device in the radiant direction, and a difference Δ
S (λ
) between these normalized spectral power distributions are respectively defined as
SSSL (λ
)=φ
SSL (λ
)/YSSL,
Sref (λ
)=φ
ref (λ
)/Yref and
Δ
S (λ
)=Sref (λ
)−
SSSL (λ
) anda wavelength that produces a longest wavelength local maximum value of SSSL (λ
) in a wavelength range of 380 nm to 780 nm is denoted by λ
R (nm), then a wavelength Λ
4 that assumes SSSL (λ
R)/2 exists on a longer wavelength-side of λ
R, andan index Acg represented by formula (3) below satisfies −
360≦
Acg≦
−
10[Expression 6]
Acg=∫
380495Δ
S(λ
)dλ
+∫
495590(−
Δ
S(λ
))dλ
+∫
590Λ
4Δ
S(λ
)dλ
(3).
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Abstract
To provide an illumination method and a light-emitting device which are capable of achieving, under an indoor illumination environment where illuminance is around 5000 lx or lower when performing detailed work and generally around 1500 lx or lower, a color appearance or an object appearance as perceived by a person, will be as natural, vivid, highly visible, and comfortable as though perceived outdoors in a high-illuminance environment, regardless of scores of various color rendition metric. Light emitted from the light-emitting device illuminates an object such that light measured at a position of the object satisfies specific requirements. A feature of the light-emitting device is that light emitted by the light-emitting device in a main radiant direction satisfies specific requirements.
15 Citations
4 Claims
-
1. A light-emitting device comprising at least a semiconductor light-emitting element as a light-emitting element, wherein
light emitted from the light-emitting device includes, in a main radiant direction thereof, light whose distance DuvSSL from a black-body radiation locus as defined by ANSI C78.377 satisfies − - 0.0350≦
DuvSSL<
0, andif a spectral power distribution of light emitted from the light-emitting device in the radiant direction is denoted by φ
SSL (λ
), a spectral power distribution of a reference light that is selected according to a correlated color temperature TSSL (K) of the light emitted from the light-emitting device in the radiant direction is denoted by φ
ref (λ
), tristimulus values of the light emitted from the light-emitting device in the radiant direction are denoted by (XSSL, YSSL, ZSSL), and tristimulus values of the reference light that is selected according to the correlated color temperature TSSL (K) of the light emitted from the light-emitting device in the radiant direction are denoted by (Xref, Yref, Zref), andif a normalized spectral power distribution SSSL (λ
) of light emitted from the light-emitting device in the radiant direction, a normalized spectral power distribution Sref (λ
) of a reference light that is selected according to the correlated color temperature TSSL (K) of the light emitted from the light-emitting device in the radiant direction, and a difference Δ
S (λ
) between these normalized spectral power distributions are respectively defined as
SSSL (λ
)=φ
SSL (λ
)/YSSL,
Sref (λ
)=φ
ref (λ
)/Yref and
Δ
S (λ
)=Sref (λ
)−
SSSL (λ
) anda wavelength that produces a longest wavelength local maximum value of SSSL (λ
) in a wavelength range of 380 nm to 780 nm is denoted by λ
R (nm), then a wavelength Λ
4 that assumes SSSL (λ
R)/2 exists on a longer wavelength-side of λ
R, andan index Acg represented by formula (3) below satisfies −
360≦
Acg≦
−
10[Expression 6]
Acg=∫
380495Δ
S(λ
)dλ
+∫
495590(−
Δ
S(λ
))dλ
+∫
590Λ
4Δ
S(λ
)dλ
(3).- View Dependent Claims (2)
(1) if an a* value and a b* value in CIE 1976 L*a*b* color space of 15 Munsell renotation color samples from #01 to #15 listed below when mathematically assuming illumination by the light emitted from the light-emitting device in the radiant direction are respectively denoted by a*nSSL and b*nSSL (where n is a natural number from 1 to
15), andan a* value and a b* value in CIE 1976 L*a*b* color space of the 15 Munsell renotation color samples when mathematically assuming illumination by a reference light that is selected according to a correlated color temperature TSSL (K) of the light emitted from the light-emitting device in the radiant direction are respectively denoted by a*nref and b*nref (where n is a natural number from 1 to
15), then each saturation difference Δ
Cn satisfies
−
3.8≦
Δ
Cn≦
18.6(where n is a natural number from 1 to
15),an average saturation difference represented by formula (1) below satisfies formula (2) below and
- 0.0350≦
-
3. A light-emitting device comprising at least a semiconductor light-emitting element as a light-emitting element, wherein
light emitted from the light-emitting device includes, in a main radiant direction thereof, light whose distance DuvSSL from a black-body radiation locus as defined by ANSI C78.377 satisfies − - 0.0350≦
DuvSSL<
0, andif a spectral power distribution of light emitted from the light-emitting device in the radiant direction is denoted by φ
SSL (λ
), a spectral power distribution of a reference light that is selected according to a correlated color temperature TSSL (K) of the light emitted from the light-emitting device in the radiant direction is denoted by φ
ref (λ
), tristimulus values of the light emitted from the light-emitting device in the radiant direction are denoted by (XSSL, YSSL, ZSSL), and tristimulus values of the reference light that is selected according to the correlated color temperature TSSL (K) of the light emitted from the light-emitting device in the radiant direction are denoted by (Xref, Yref, Zref), andif a normalized spectral power distribution SSSL (λ
) of light emitted from the light-emitting device in the radiant direction, a normalized spectral power distribution Sref (λ
) of reference light that is selected according to the correlated color temperature TSSL (K) of the light emitted from the light-emitting device in the radiant direction, and a difference Δ
S (λ
) between these normalized spectral power distributions are respectively defined as
SSSL (λ
)=φ
SSL (λ
)/YSSL,
Sref (λ
)=φ
ref (λ
)/Yref and
Δ
S (λ
)=Sref (λ
)−
SSSL (λ
), anda wavelength that produces a longest wavelength local maximum value of SSSL (λ
) in a wavelength range of 380 nm to 780 nm is denoted by λ
R (nm), then a wavelength Λ
4 that assumes SSSL (λ
R)/2 does not exist on a longer wavelength-side of λ
R, andan index Acg represented by formula (4) below satisfies −
360≦
Acg≦
−
10[Expression 7]
Acg=∫
380495Δ
S(λ
)dλ
+∫
495590(−
Δ
S(λ
))dλ
+∫
590780Δ
S(λ
)dλ
(4).- View Dependent Claims (4)
(1) if an a* value and a b* value in CIE 1976 L*a*b* color space of 15 Munsell renotation color samples from #01 to #15 listed below when mathematically assuming illumination by the light emitted from the light-emitting device in the radiant direction are respectively denoted by a*nSSL and b*nSSL (where n is a natural number from 1 to
15), andan a* value and a b* value in CIE 1976 L*a*b* color space of the 15 Munsell renotation color samples when mathematically assuming illumination by a reference light that is selected according to a correlated color temperature TSSL (K) of the light emitted from the light-emitting device in the radiant direction are respectively denoted by a*nref and b*nref (where n is a natural number from 1 to
15), then each saturation difference Δ
Cn satisfies
−
3.8≦
Δ
Cn≦
18.6(where n is a natural number from 1 to
15),an average saturation difference represented by formula (1) below satisfies formula (2) below and
- 0.0350≦
Specification
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Current AssigneeCitizen Electronics Company Limited
-
Original AssigneeCitizen Electronics Company Limited
-
InventorsHorie, Hideyoshi
-
Primary Examiner(s)Islam, Mohammad
-
Assistant Examiner(s)Mehta, Ratisha
-
Application NumberUS14/927,703Publication NumberTime in Patent Office361 DaysField of SearchUS Class Current1/1CPC Class CodesC09K 11/08 containing inorganic lumine...H01L 2924/00 Indexing scheme for arrange...H01L 2924/0002 Not covered by any one of g...H01L 33/30 containing only elements of...H01L 33/32 containing nitrogenH01L 33/48 characterised by the semico...H01L 33/50 Wavelength conversion elementsH01L 33/502 Wavelength conversion mater...H01L 33/504 Elements with two or more w...H05B 45/20 Controlling the colour of t...H05B 45/22 using optical feedbackH05B 45/24 using electrical feedback f...
