Semiconductor light emitting device, backlight, color image display device and phosphor to be used for them

1. A color image display device comprising:

a solid light emitting device to emit light in a blue or deep blue region or in an ultraviolet region and

a phosphor,

wherein the phosphor comprises a red emitting phosphor containing Mn 4+ as an activated element, and

an NTSC ratio representing the color reproduction range is at least 87%.

2. The color image display device of claim 1 ,

wherein the red emitting phosphor comprises a crystal phase having a chemical composition represented by any one of formulae (1) to (8):

M I 2 [M IV 1−x R x F 6 ]  (1)

M I 3 [M III 1−x R x F 6 ]  (2)

M II [M IV 1−x R x F 6 ]  (3)

M I 3 [M IV 1−x R x F 7 ]  (4)

M I 2 [M III 1−x R x F 5 ]  (5)

Zn 2 [M III 1−x R x F 7 ]  (6)

M I [M III 2−2x R 2x F 7 ]  (7)

Ba 0.65 Zr 0.35 F 2.70 :Mn 4+   (8)

wherein in the formulae (1) to (8),

M I is at least one monovalent group selected from the group consisting of Li, Na, K, Rb, Cs and NH 4 , M II is an alkaline earth metal element,

M III is at least one metal element selected from the group consisting of Groups 3 and 13 of the Periodic Table,

M IV is at least one metal element selected from the group consisting of Groups 4 and 14 of the Periodic Table,

R is an activated element comprising at least Mn, and

x is a numerical value of 0<x<1.

3. The color image display device of claim 1 ,

wherein the red emitting phosphor comprises a crystal phase having a chemical composition represented by the formula (1′):

M I′ 2 M IV′ F 6 :R  (I′)

wherein

M I′ is at least one element selected from the group consisting of K and Na,

M IV′ is at least one metal element selected from the group consisting of Groups 4 and 14 of the Periodic Table comprising at least Si, and

R is an activated element comprising at least Mn 4+ ,

wherein the proportion of Mn based on the total mols of M IV′ and Mn is at least 0.1 mol % and at most 40 mol %, and the specific surface area is at most 1.3 m 2 /g.

4. The color image display device of claim 3 ,

wherein the proportion of Mn based on the total mols of M IV′ and Mn is at least 0.1 mol % and at most 18 mol %.

5. The color image display device of claim 3 ,

wherein the proportion of Mn based on the total mols of M IV′ and Mn is at least 0.1 mol % and at most 6 mol %.

6. The color image display device of claim 2 ,

wherein the phosphor has a weight-average median diameter D 50 of at least 3 μm and at most 30 μm.

7. The color image display device of claim 2 ,

wherein the red emitting phosphor has a main emission peak with a half-value width of at most 10 nm in a wavelength region of from 610 to 650 nm.

8. The color image display device of claim 2 ,

wherein the red emitting phosphor has at least one emission peak with a half-value width of at most 10 nm in a wavelength region of from 610 to 650 nm; and

the red emitting phosphor has the variation rate of the emission peak intensity at 100° C. to the emission intensity at 25° C. of at most 40%, when the wavelength of the excitation light is 400 nm or 455 nm.

9. The color image display device of claim 1 ,

wherein the phosphor further comprises a green emitting phosphor.

10. The color image display device of claim 9 ,

wherein the green emitting phosphor comprises at least one compound selected from the group consisting of an oxynitride phosphor, a sialon phosphor, an aluminate phosphor and an orthosilicate phosphor.

11. The color image display device of claim 1 ,

wherein the light use efficiency y is

γ>−0.4 W +64,

wherein W>85.

12. The color image display device of claim 1 , wherein the color temperature is from 4,000 to 10,000 K.