WHITE LIGHT-EMITTING SEMICONDUCTOR DEVICES

• US 20120112626A1
• Filed: 11/09/2011
• Published: 05/10/2012
• Est. Priority Date: 08/26/2009
• Status: Active Grant

• Current Assignee: CMC Magnetics Corporation
• Original Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Inventors: Satou, Yoshihito, Hiraoka, Shin, SAKUTA, Hiroaki, KAGAWA, Kazuhiko, Okagawa, Hiroaki
• Granted Patent: US 8,581,488 B2
• Time in Patent Office: Days
• US Class Current: 313/501
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7718 with alkaline earth metals
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: C09K 11/77347 Silicon Nitrides or Silicon Oxynitrides
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/7738 with alkaline earth metals
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: C09K 11/77742 Silicates
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A white light-emitting semiconductor device having improved reproducibility of bright red. The device outputs light having a blue component, a green component, and a red component. Each of the light components (blue, green, and red) consists of a light-emitting semiconductor element and/or a phosphor that absorbs light emitted by a light-emitting semiconductor element and emits light through wavelength conversion. The outputted light has a spectrum which has a maximum wavelength in the range of 615-645 nm, and the intensity at a wavelength of 580 nm of the outputted light, which has been normalized with respect to luminous flux, is 80-100% of the intensity at a wavelength of 580 nm of standard light for color rendering evaluation, which has been normalized with respect to luminous flux.

Claims

1. A white light-emitting semiconductor device which outputs light comprising a blue light component, a green light component, and a red light component, wherein

the blue light component includes light having any wavelength in the range of 440-480 nm,

the green light component includes light having any wavelength in the range of 515-560 nm, and

the red light component includes light having any wavelength in the range of 615-645 nm,

a source of the blue light component comprises a light-emitting semiconductor element and/or a first phosphor that absorbs the light emitted by a light-emitting semiconductor element and emits, through wavelength conversion, light including the blue light component,

a source of the green light component comprises a second phosphor that absorbs the light emitted by a light-emitting semiconductor element and emits, through wavelength conversion, light including the green light component, and

a source of the red light component comprises a third phosphor that absorbs the light emitted by a light-emitting semiconductor element and emits, through wavelength conversion, light including the red light component,

the outputted light has a spectrum which has a maximum wavelength in the range of 615-645 nm, and

an intensity at a wavelength of 580 nm of the spectrum of the outputted light which has been normalized with respect to luminous flux, is 80-100% of an intensity at a wavelength of 580 nm of the spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

2. The white light-emitting semiconductor device according to claim 1, wherein the source of the blue light component comprises a blue light-emitting semiconductor element or comprises a blue phosphor as the first phosphor, the second phosphor comprises a green phosphor, and the third phosphor comprises a red phosphor.

3. The white light-emitting semiconductor device according to claim 1, wherein the third phosphor comprises a first red phosphor and a second red phosphor, and the second red phosphor has a lower relative intensity at a wavelength of 580 nm in an emission spectrum, when the intensity at the peak wavelength is taken as 1, than in the first red phosphor.

4. The white light-emitting semiconductor device according to claim 3, wherein the source of the blue light component comprises, as the blue light-emitting semiconductor element, a blue light-emitting diode element which has an emission peak wavelength in the range of 440-470 nm.

5. The white light-emitting semiconductor device according to claim 3, wherein the source of the blue light component comprises a blue phosphor as the first phosphor, and an excitation source of the blue phosphor comprises an InGaN-based light-emitting diode element having an emission peak wavelength in the range of 400-420 nm.

6. The white light-emitting semiconductor device according to claim 3, wherein the second phosphor comprises one or more phosphors selected from green phosphors which comprise Eu²⁺ as an activator and crystals containing an alkaline earth silicate, an alkaline earth silicate nitride, or Sialon as a base, and green phosphors which comprise Ce³⁺ as an activator and crystals containing a garnet-type oxide or an alkaline earth metal scandate as a base.

7. The white light-emitting semiconductor device according to claim 1, wherein the second phosphor comprises a green phosphor and a yellow phosphor.

8. The white light-emitting semiconductor device according to claim 1, wherein the outputted light has a spectrum which has a maximum wavelength in the range of 615 nm or more and less than 630 nm, and an intensity at a wavelength of 580 nm of the spectrum of the outputted light which has been normalized with respect to luminous flux, is 85-100% of an intensity at a wavelength of 580 nm of the spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

9. The white light-emitting semiconductor device according to claim 1, wherein the outputted light has a spectrum which has a maximum wavelength in the range of 630-645 nm, and an intensity at a wavelength of 580 nm of the spectrum of the outputted light which has been normalized with respect to luminous flux is 90-100% of an intensity at a wavelength of 580 nm of the spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

23. An illuminating device comprising the white light-emitting semiconductor device according to claim 1 or 20, or the white light-emitting unit according to claim 10 or 13.

10. A white light-emitting unit which emits white light containing a blue light component, a green light component, and a red light component, wherein

the blue light component includes light having any wavelength in the range of 440-480 nm,

the green light component includes light having any wavelength in the range of 515-560 nm, and

the red light component includes light having any wavelength in the range of 615-645 nm,

the white light-emitting unit comprises:

a light-emitting semiconductor element,

a first phosphor that absorbs the light emitted by the light-emitting semiconductor element and emits, through wavelength conversion, light including the blue light component,

a second phosphor that absorbs the light emitted by the light-emitting semiconductor element and emits, through wavelength conversion, light including the green light component, and

a third phosphor that absorbs the light emitted by the light-emitting semiconductor element and emits, through wavelength conversion, light including the red light component,

the white light has a spectrum which has a maximum wavelength in the range of 615-645 nm, and

an intensity at a wavelength of 580 nm of the spectrum of the white light which has been normalized with respect to luminous flux is 80-100% of an intensity at a wavelength of 580 nm of the spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

11. The white light-emitting unit according to claim 10, wherein the first phosphor comprises a blue phosphor, the second phosphor comprises a green phosphor, and the third phosphor comprises a red phosphor.

12. The white light-emitting unit according to claim 11, wherein the light-emitting semiconductor element comprises an InGaN-based light-emitting diode element having an emission peak wavelength in the range of 400-420 nm.

15. The white light-emitting unit according to claim 10 or 13, wherein the second phosphor comprises one or more phosphors selected from green phosphors which comprise Eu²⁺ as an activator and crystals containing an alkaline earth silicate, an alkaline earth silicate nitride, or Sialon as a base, and green phosphors which comprise Ce³⁺ as an activator and crystals containing a garnet-type oxide or an alkaline earth metal scandate as a base.

16. The white light-emitting unit according to claim 10 or 13, wherein the second phosphor comprises a green phosphor and a yellow phosphor.

17. The white light-emitting unit according to claim 10 or 13, wherein the white light has a spectrum which has a maximum wavelength in the range of 615 nm or more and less than 630 nm, and an intensity at a wavelength of 580 nm of the spectrum of the white light which has been normalized with respect to luminous flux is 85-100% of an intensity at a wavelength of 580 nm of the spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

18. The white light-emitting unit according to claim 10 or 13, wherein the white light has a spectrum which has a maximum wavelength in the range of 630-645 nm, and an intensity at a wavelength of 580 nm of the spectrum of the white light which has been normalized with respect to luminous flux is 90-100% of the intensity at a wavelength of 580 nm of the spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

19. The white light-emitting unit according to claim 10 or 13, wherein the third phosphor comprises a first red phosphor and a second red phosphor, and the second red phosphor has a lower relative intensity at a wavelength of 580 nm in an emission spectrum, when the intensity at the peak wavelength is taken as 1, than in the first red phosphor.

13. A white light-emitting unit which emits white light containing a blue light component, a green light component, and a red light component, wherein

the blue light component includes light having any wavelength in the range of 440-480 nm,

the green light component includes light having any wavelength in the range of 515-560 nm, and

the red light component includes light having any wavelength in the range of 615-645 nm,

the white light-emitting unit comprises:

a light-emitting semiconductor element that emits light including the blue light component,

a second phosphor that absorbs the light emitted by the light-emitting semiconductor element and emits, through wavelength conversion, light including the green light component, and

a third phosphor that absorbs the light emitted by the light-emitting semiconductor element and emits, through wavelength conversion, light including the red light component,

the white light has a spectrum which has a maximum wavelength in the range of 615-645 nm, and

an intensity at a wavelength of 580 nm of the spectrum of the white light which has been normalized with respect to luminous flux is 80-100% of an intensity at a wavelength of 580 nm of the spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

14. The white light-emitting unit according to claim 13, wherein the light-emitting semiconductor element comprises a blue light-emitting semiconductor element, the second phosphor comprises a green phosphor, and the third phosphor comprises a red phosphor.

20. A white light-emitting semiconductor device comprising first to Nth (wherein N is an integer of 2 or larger) white light-emitting units each equipped with a light-emitting semiconductor element and a wavelength conversion part, in which the first to Nth white light-emitting units each emit primary white light and the primary white light emitted by the units is mixed together, to form combined light as outputted light, wherein

the first to Nth white light-emitting units comprise a white light-emitting unit which emits first primary white light and a white light-emitting unit which emits second primary white light,

an intensity at a wavelength of 580 nm of the spectrum of the first primary white light which has been normalized with respect to luminous flux is higher than an intensity at a wavelength of 580 nm of the spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux,

an intensity at a wavelength of 580 nm of the spectrum of the second primary white light which has been normalized with respect to luminous flux is lower than an intensity at a wavelength of 580 nm of the spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux, and

the outputted light has a spectrum which has a maximum wavelength in the range of 615-645 nm, and an intensity at a wavelength of 580 nm of the spectrum of the outputted light which has been normalized with respect to luminous flux is 80-100% of an intensity at a wavelength of 580 nm of the spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

21. The white light-emitting semiconductor device according to claim 20, wherein the white light-emitting unit which emits first primary white light comprises a wavelength conversion part including a first red phosphor, and the white light-emitting unit which emits second primary white light comprises a wavelength conversion part including a second red phosphor, and the second red phosphor has a lower relative intensity at a wavelength of 580 nm in an emission spectrum, when the intensity at the peak wavelength is taken as 1, than in the first red phosphor.

22. The white light-emitting semiconductor device according to claim 20, wherein a difference in reciprocal correlated color temperature between the first primary white light and the second primary white light is 50 MK⁻

1 or less.