Light-emitting device, method for designing light-emitting device, method for driving light-emitting device, illumination method, and method for manufacturing light-emitting device

1. A light-emitting device incorporating a light-emitting element and satisfying the following A or B, wherein

φ SSL (λ) emitted from the light-emitting device satisfies both the following Condition 1 and Condition 2:

A: a light-emitting device which includes M number of light emitting areas (M is 2 or greater natural number) and has the light-emitting elements in the light emitting areas, wherein

when φ SSL N(λ) (N is 1 to M) is a spectral power distribution of a light emitted from each light emitting area in a main radiant direction of the light-emitting device, φ SSL (λ), which is a spectral power distribution of all the lights emitted from the light-emitting device in the radiant direction, is

[

Expression

⁢

⁢

1

]

ϕ

SSL

⁡

(

λ

)

=

∑

N

=

1

M

⁢

ϕ

SSL

⁢

N

⁡

(

λ

)

,

B: a light-emitting device incorporating the light-emitting element and a control element, wherein

if a wavelength is denoted by λ(nm), a spectral power distribution of a light emitted from the light-emitting element in a main radiant direction is denoted by Φ elm (λ), and a spectral power distribution of a light emitted from the light-emitting device in the main radiant direction is denoted by φ SSL (λ),

Φ elm (λ) does not satisfy at least one of the following Conditions 1 and 2:

Condition 1:

light emitted from the light-emitting device includes, in the main radiant direction thereof, light whose distance D uvSSL from a black-body radiation locus as defined by ANSI C78.377 satisfies −0.0350≦D uvSSL ≦−0.0040,

Condition 2:

if 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 T SSL (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 (X SSL , Y SSL , Z SSL ), and tristimulus values of the reference light that is selected according to T SSL (K) of the light emitted from the light-emitting device in the radiant direction are denoted by (X ref , Y ref , Z ref ), and

if a normalized spectral power distribution S SSL (λ) of light emitted from the light-emitting device in the radiant direction, a normalized spectral power distribution S ref (λ) of a reference light that is selected according to T SSL (K) of the light emitted from the light-emitting device in the radiant direction, and a difference ΔS (λ) between these normalized spectral power distributions are respectively defined as

S SSL (λ)=φ SSL (λ)/ Y SSL ,

S ref (λ)=φ ref (λ)/ Y ref

and

Δ S (λ)= S ref (λ)− S SSL (λ) and

an index A cg represented by the following Formula (1) satisfies −360≦A cg ≦−10, in the case when a wavelength that produces a longest wavelength local maximum value of S SSL (λ) in a wavelength range from 380 nm to 780 nm is denoted by λ R (nm), and a wavelength Λ4 that assumes S SSL (λ R )/2 exists on a longer wavelength-side of λ R , and

an index A cg represented by the following Formula (2) satisfies −360≦A cg ≦−10, in the case when a wavelength that produces a longest wavelength local maximum value of S SSL (λ) in a wavelength range from 380 nm to 780 nm is denoted by λ R (nm), and a wavelength Λ4 that assumes S SSL (λ R )/2 does not exist on a longer wavelength-side of λ R ,

[Expression 2]

A cg =∫ 380 495 ΔS (λ) dλ+∫ 495 590 (−Δ S (λ)) dλ+∫ 590 Λ4 ΔS (λ) dλ   (1)

[Expression 3]

A cg =∫ 380 495 ΔS (λ) dλ+∫ 495 590 (−Δ S (λ)) dλ+∫ 590 780 ΔS (λ) dλ   (2).

2. The light-emitting device according to claim 1 , satisfying the A.

3. The light-emitting device according to claim 2 , wherein

a semiconductor light-emitting element is included in at least one of the light emitting areas as the light-emitting element.

4. The light-emitting device according to claim 2 , including light emitting areas so that φ SSL (λ) can satisfy the Conditions 1 to 2 by changing a luminous flux amount and/or a radiant flux amount emitted from the light emitting areas.

5. The light-emitting device according to claim 2 , wherein

all of φ SSL N(λ) (N is 1 to M) satisfies the Condition 1 and Condition 2.

6. The light-emitting device according to claim 2 , wherein

at least one light emitting area of the M number of light emitting areas has wiring that allows the light emitting area to be electrically driven independently from other light emitting areas.

7. The light-emitting device according to claim 6 , wherein

all the M numbers of light emitting areas each have wiring that allows the light emitting area to be electrically driven independently from other light emitting areas.

8. The light-emitting device according to claim 2 , wherein

at least one selected from the group consisting of the index A cg represented by the Formula (1) or (2), the correlated color temperature T SSL (K) and the distance D uvSSL from the black-body radiation locus can be changed.

9. The light-emitting device according to claim 8 , wherein

a luminous flux and/or a radiant flux emitted from the light-emitting device in the main radiant direction can be independently controlled when at least one selected from the group consisting of the index A cg represented by the Formula (1) or (2), the correlated color temperature T SSL (K) and the distance D uvSSL from the black-body radiation locus is changed.

10. The light-emitting device according to claim 2 , wherein

a maximum distance L between two arbitrary points on a virtual outer periphery enveloping the entire light emitting areas closest to each other, is 0.4 mm or more and 200 mm or less.

11. The light-emitting device according to claim 2 , including the light emitting areas that allow φ SSL (λ) to further satisfy the following Conditions 3 to 4 by changing a luminous flux amount and/or a radiant flux amount emitted from the light emitting areas:

Condition 3:

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 in the radiant direction are respectively denoted by a* nSSL and b* nSSL (where n is a natural number from 1 to 15), and

if an 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 T SSL (K) of the light emitted 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 ΔC n satisfies

−3.8ΔC n ≦18.6 (where n is a natural number from 1 to 15), and

an average saturation difference represented by formula (3) below satisfies formula (4) below and

[

Expression

⁢

⁢

4

]

∑

n

=

1

15

⁢

Δ

⁢

⁢

C

n

15

(

3

)

[

Expression

⁢

⁢

5

]

1.0

≦

∑

n

=

1

15

⁢

Δ

⁢

⁢

C

n

15

≦

7.0

,

(

4

)

if a maximum saturation difference value is denoted by ΔC max and a minimum saturation difference value is denoted by ΔC min , then a difference |ΔC max −ΔC min | between the maximum saturation difference value and the minimum saturation difference value satisfies

2.8≦|Δ C max −ΔC min |≦19.6,

where ΔC n =√{(a* nSSL ) 2 +(b* nSSL ) 2 }−√{(a* nref ) 2 +(b* nref ) 2 }

with the 15 Munsell renotation color samples being:

#01

7.5P 4/10

#02

10PB 4/10

#03

5PB 4/12

#04

7.5B 5/10

#05

10BG 6/8

#06

2.5BG 6/10

#07

2.5G 6/12

#08

7.5GY 7/10

#09

2.5GY 8/10

#10

5Y 8.5/12

#11

10YR 7/12

#12

5YR 7/12

#13

10R 6/12

#14

5R 4/14

#15

7.5RP 4/12

Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsell renotation color samples when mathematically assuming illumination by the light emitted in the radiant direction are denoted by θ nSSL (degrees) (where n is a natural number from 1 to 15), and

if hue angles in a 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 the correlated color temperature T SSL (K) of the light emitted in the radiant direction are denoted by θ nref (degrees) (where n is a natural number from 1 to 15), then an absolute value of each difference in hue angles |Δh n | satisfies

0≦|Δh n |≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh n =θ nSSL −θ nref .

12. The light-emitting device according to claim 2 , wherein

a luminous efficacy of radiation K (lm/W) in a wavelength range from 380 nm to 780 nm as derived from the spectral power distribution φ SSL (λ) of light emitted from the light-emitting device in the radiant direction satisfies

180(lm/W)≦ K (lm/W)≦320(lm/W).

13. The light-emitting device according to claim 2 , wherein

a correlated color temperature T SSL (K) of light emitted from the light-emitting device in the radiant direction satisfies

2550( K )≦ T SSL ( K )≦5650( K ).

14. The light-emitting device according to claim 1 , satisfying the B.

15. The light-emitting device according to claim 14 , wherein

the light-emitting element includes a semiconductor light-emitting element.

16. The light-emitting device according to claim 14 , wherein

Φ elm (λ) does not satisfy at least one of the following Condition 3 and Condition 4, and φ SSL (λ) satisfies both the following Condition 3 and Condition 4:

Condition 3:

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 target light are respectively denoted by a* n and b* n (where n is a natural number from 1 to 15), and

if an 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 T (K) of the light emitted 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 ΔC n satisfies

−3.8≦ΔC n ≦18.6 (where n is a natural number from 1 to 15), and

an average SAT av of saturation difference represented by formula (3) below satisfies formula (4) below and

[

Expression

⁢

⁢

6

]

SAT

av

=

∑

n

=

1

15

⁢

Δ

⁢

⁢

C

n

15

(

3

)

[

Expression

⁢

⁢

7

]

1.0

≦

∑

n

=

1

15

⁢

Δ

⁢

⁢

C

n

15

≦

7.0

,

(

4

)

if a maximum saturation difference value is denoted by ΔC max and a minimum saturation difference value is denoted by ΔC min then a difference |ΔC max −ΔC min | between the maximum saturation difference value and the minimum saturation difference value satisfies

2.8≦|Δ C max −ΔC min |≦19.6

where ΔC n =√{(a* n ) 2 +(b* n ) 2 }−√{(a* nref ) 2 +(b* nref ) 2 }

with the 15 Munsell renotation color samples being:

#01

7.5P 4/10

#02

10PB 4/10

#03

5PB 4/12

#04

7.5B 5/10

#05

10BG 6/8

#06

2.5BG 6/10

#07

2.5G 6/12

#08

7.5GY 7/10

#09

2.5GY 8/10

#10

5Y 8.5/12

#11

10YR 7/12

#12

5YR 7/12

#13

10R 6/12

#14

5R 4/14

#15

7.5RP 4/12

Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsell renotation color samples when mathematically assuming illumination by the target light are denoted by θ n (degrees) (where n is a natural number from 1 to 15), and

if hue angles in a 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 the correlated color temperature T (K) of the light emitted in the radiant direction are denoted by θ nref (degrees) (where n is a natural number from 1 to 15), then an absolute value of each difference in hue angles |Δh n | satisfies

0≦|Δh n |≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh n =θ n −θ nref .