Illumination method and light-emitting device

Patent metadata

Field	Value
Publication number	US-9305970-B2
Application number	US-201414196662-A
Country	US
Kind code	B2
Filing date	Mar 4, 2014
Priority date	Sep 2, 2011
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

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.

First claim

The invention claimed is:

1. An illumination method comprising:
illuminated objects preparation step of preparing illuminated objects; and an illumination step of illuminating the objects by light emitted from light-emitting devices, wherein
in the illumination step, when light emitted from the light-emitting devices illuminate the objects, the objects are illuminated so that the light measured at a position of the objects satisfies (1), (2), and (3) below:

(1) a distance D uvSSL from a black-body radiation locus as defined by ANSI C78.377 of the light measured at the position of the objects satisfies −0.0325≦D uvSSL ≦−0.0075;
(2) 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 measured at the position of the objects 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 measured at the position of the objects 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
−2.7≦Δ C n ≦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

[

Expression
⁢

⁢
1

]

∑

n
=
1

15

⁢

Δ
⁢

⁢

C
n

15

(
1
)

[

Expression
⁢

⁢
2

]

1.7
≦

∑

n
=
1

15

⁢

Δ
⁢

⁢

C
n

15

≦
7.0

(
2
)

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
3.0≦(|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

(3) 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 measured at the position of the objects are denoted by θ nSSL (degrees) (where n is a natural number from 1 to 15), and
if hue angles 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 the correlated color temperature T SSL (K) of the light measured at the position of the objects 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≦|Δ h n |≦9.0 (degrees) (where n is a natural number from 1 to 15),

where Δh n =θ nSSL −η nref .

Assignees

• Citizen Electronics Company Ltd
• Citizen Electronics

Inventors

• Horie Hideyoshi

Classifications

• H05B45/20

  Controlling the colour of the light · CPC title

• F21K9/233

  specially adapted for generating a spot light distribution, e.g. for substitution of reflector lamps · CPC title

• F21Y2115/10

  Light-emitting diodes [LED] · CPC title

• H05B45/22

  using optical feedback · CPC title

• H05B33/02

  Details · CPC title