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

• US 9,530,821 B2
• Filed: 09/04/2015
• Issued: 12/27/2016
• Est. Priority Date: 03/04/2013
• Status: Active Grant

• Current Assignee: Citizen Electronics Company Limited
• Original Assignee: Citizen Electronics Company Limited
• Inventors: Horie, Hideyoshi
• Primary Examiner(s): NGUYEN, TUAN N
• Application Number:
  US14/845,436
• Publication Number:
  US 20150380460A1
• Time in Patent Office: 480 Days
• Field of Search: 257/89
• US Class Current: 1/1
• CPC Class Codes: H01L 25/13 the devices being of a type provided for in group H01L33/00
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/30 Driver circuits

Abstract

A light-emitting device that can implement a natural, vivid, highly visible and comfortable appearance of colors and appearance of objects as if the objects are seen outdoors is provided. The light-emitting device can change the appearance of colors of the illuminated objects so as to satisfy the requirements for various illuminations. Furthermore, the appearance of colors of the light-emitting device which currently exists or is in use, and which includes a semiconductor light-emitting device of which appearance of colors is not very good, is improved. A method for driving the light-emitting device, an illumination method by the device, and a method for manufacturing the light-emitting device are also provided. These features are achieved by the light-emitting device that incorporates light-emitting elements and satisfies predetermined requirements, in which φ_SSL(λ) emitted from the light-emitting device satisfies a predetermined condition.

Claims

1. A light-emitting device comprising a light-emitting element and satisfying the following A or B:

A;

the light-emitting device comprises M number of light emitting areas, where M is 2 or greater natural number, and has the light-emitting elements in the light emitting areas, wherein

when φ

_SSLN(λ

), with N being 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

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 and 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 the φ

_SSLN(λ

), with N being 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, comprising 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 Δ

C_n satisfies

−

3.8≦

Δ

C_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

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 Δ

C_n satisfies

−

3.8≦

Δ

C_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