Phosphors for white light generation from UV emitting diodes

• US 6,294,800 B1
• Filed: 11/30/1998
• Issued: 09/25/2001
• Est. Priority Date: 02/06/1998
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Davenport, John Martin, Srivastava, Alok Mani, Duggal, Anil Raj, Beers, William Winder, Soules, Thomas Frederick
• Primary Examiner(s): Tran, Minh Loan
• Application Number:
  US09/203,214
• Time in Patent Office: 1,030 Days
• Field of Search: 257/88, 257/89, 257/98, 257/99, 257/100, 313/501-504, 313/512
• US Class Current: 257/89
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• 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

Ca₈Mg(SiO₄)₄Cl₂:Eu²⁺,Mn²⁺ and Y₂O₃:Eu³⁺,Bi³⁺ are phosphors which have been sensitized to absorb ultraviolet radiation, such as from a light emitting diode, and to convert the radiation into visible light. A phosphor conversion material blend comprises Ca₈Mg(SiO₄)₄Cl₂:Eu²⁺,Mn²⁺; Y₂O₃:Eu³⁺,Bi³⁺, and known blue phosphors that absorb ultraviolet radiation from a LED and convert the radiation into visible bright white light. Also, a light emitting assembly comprises at least one of a red, green and blue phosphor for absorbing and converting ultraviolet radiation into visible light. A laser diode can be used to activate the phosphors to provide improved efficiency and brightness.

Claims

1. A composition of matter comprising Ca₈Mg(SiO₄)₄Cl₂:

Eu²⁺,Mn²⁺.

2. The composition of matter according to claim 1 further comprising:

at least one red light emitting phosphor and

at least one blue light emitting phosphor;

the composition of matter capable of converting a radiation to visible light, the radiation having a wavelength in a range from ultraviolet to blue.

3. The composition of matter according to claim 2 wherein said wavelength is in a range from about 330 nm to about 420 nm.

4. The composition of matter according to claim 2 wherein said wavelength is in a range from about 350 nm to about 400 nm.

5. The composition of matter according to claim 2 wherein said wavelength is in a range from about 355 nm to about 365 nm.

6. A phosphor conversion material blend composition that is capable of converting ultraviolet radiation to visible light, the phosphor conversion material blend composition comprising:

at least one red light emitting phosphor;

at least one green light emitting phosphor; and

at least one blue light emitting phosphor;

wherein the green light emitting phosphor comprises Ca₈Mg(SiO₄)₄Cl₂;

Eu²⁺,Mn²⁺;

the red light emitting phosphor comprises Y₂O₃;

Eu³⁺,Bi³⁺; and

the blue light emitting phosphor comprises at least one material selected from the group consisting of (Sr,Ba,Ca)₅(PO₄)₃Cl;

Eu²⁺ and BaMg₂Al₁₆O₂₇;

Eu²⁺.

7. A phosphor conversion material blend composition that is capable of converting ultraviolet radiation to visible light, the phosphor conversion material blend composition comprising:

at least one red light emitting phosphor;

at least one green light emitting phosphor; and

at least one blue light emitting phosphor,

wherein the green light emitting phosphor comprises Ca₈Mg(SiO₄)₄Cl₂;

Eu²⁺,Mn²⁺;

the red light emitting phosphor comprises Y₂O₃;

Eu³⁺,Bi³⁺, and the blue light emitting phosphor comprises at least one material selected from the group consisting of (Sr,Ba,Ca)₅(PO₄)Cl;

Eu²⁺ and BaMg₂Al₁₆O₂₇;

Eu²⁺, and

wherein the Y₂O₃;

Eu³⁺,Bi³⁺ is provided in a range between about 40% to about 80% by weight;

the Ca₈Mg(SiO₄)₄Cl₂;

Eu²⁺,Mn²⁺ is provided in a range between about 20% to about 50% by weight; and

the at least one material selected from the group consisting of (Sr,Ba,Ca)₅(PO₄)₃Cl;

Eu²⁺ and BaMg₂Al₁₆O₂₇;

Eu²⁺ is provided in a range between 5% and about 25% by weight.

8. A light emitting diode comprising:

a semiconductor ultraviolet radiation source; and

a phosphor comprising Ca₈Mg(SiO₄)₄Cl₂;

Eu²⁺,Mn²⁺ radiationally coupled to the semiconductor ultraviolet radiation source;

wherein the Ca₈Mg(SiO₄)₄Cl₂;

Eu²⁺,Mn²⁺ is capable of absorbing ultraviolet radiation emitted by the semiconductor ultraviolet radiation source and converting the ultraviolet radiation into a green visible light.

9. The light emitting diode according to claim 8 further comprising

a phosphor comprising Y₂O₃: Eu³⁺,Bi³⁺ radiationally coupled to the semiconductor to the semiconductor ultraviolet radiation source;

wherein the Y₂O₃;

Eu³⁺,Bi³⁺ is capable of absorbing ultraviolet radiation emitted by the semiconductor ultraviolet radiation source and converting the ultraviolet radiation into a red visible light.

10. The light emitting diode according to claim 8 further comprising

a phosphor comprising at least one material selected from the group consisting of (Sr,Ba,Ca)₅(PO₄)₃Cl:

Eu²⁺ and BaMg₂Al₁₆O₂₇;

Eu²⁺ radiationally coupled to the semiconductor to the semiconductor ultraviolet radiation source;

wherein the at least one material selected from the group consisting of (Sr,Ba,Ca)₅(PO₄)₃Cl;

Eu²⁺ and BaMg₂Al₁₆O₂₇;

Eu²⁺ is capable of absorbing ultraviolet radiation emitted by the semiconductor ultraviolet radiation source and converting the ultraviolet radiation into a blue visible light.

11. The light emitting diode according to claim 8 further comprising

a phosphor conversion material blend composition comprising:

a phosphor which is capable of absorbing ultraviolet radiation emitted by the semiconductor ultraviolet radiation source and converting the ultraviolet radiation into a red visible light; and

a phosphor which is capable of absorbing ultraviolet radiation emitted by the semiconductor ultraviolet radiation source and converting the ultraviolet radiation into a blue visible light.

12. The light emitting diode according to claim 11 wherein the phosphor which is capable of absorbing ultraviolet radiation emitted by the semiconductor ultraviolet radiation source and converting the ultraviolet radiation into a red visible light comprises Y₂O₃:

Eu³⁺,Bi³⁺.

13. The light emitting diode according to claim 11 wherein the phosphor which is capable of absorbing ultraviolet radiation emitted by the semiconductor ultraviolet radiation source and converting the ultraviolet radiation into a blue visible light comprises at least one material selected from the group consisting of (Sr,Ba,Ca)₅(PO₄)₃Cl:

Eu²⁺ and BaMg₂Al₁₆O₂₇;

Eu²⁺.

14. The light emitting diode according to claim 11 wherein the phosphor conversion material blend composition absorbs ultraviolet radiation emitted by the semiconductor ultraviolet radiation source and converts the ultraviolet radiation into white visible light to provide a light source having a light output of at least 20 lumens per watt.

15. The light emitting diode according to claim 11 wherein the phosphor conversion material blend composition absorbs ultraviolet radiation emitted by the semiconductor ultraviolet radiation source and converts the ultraviolet radiation into white visible light to provide a light source having a color rendering index of at least 84.

16. A light emitting diode comprising:

a semiconductor ultraviolet radiation source; and

a phosphor conversion material blend composition, wherein the phosphor conversion material composition absorbs ultraviolet radiation emitted by the semiconductor ultraviolet radiation source and converts the ultraviolet radiation into white visible light, and wherein the composition comprises;

Ca₈Mg(SiO₄)₄Cl₂;

Eu²⁺,Mn²⁺ radiationally coupled to the semiconductor ultraviolet radiation source;

Y₂O₃;

Eu³⁺,Bi³⁺ radiationally coupled to the semiconductor ultraviolet radiation source; and

at least one of (Sr,Ba,Ca)₅(PO₄)₃Cl;

Eu²⁺ and BaMg₂Al₁₆O₂₇;

Eu²⁺ radiationally coupled to the semiconductor ultraviolet radiation source;

wherein the composition is capable of absorbing ultraviolet source and converting the ultraviolet radiation into visible light.

17. A light emitting diode comprising:

a semiconductor ultraviolet radiation source; and

a phosphor conversion material blend composition, wherein the phosphor conversion material composition absorbs ultraviolet radiation emitted by the semiconductor ultraviolet radiation source and converts the ultraviolet radiation into white visible light, and wherein the composition comprises;

Ca₈Mg(SiO₄)₄Cl₂;

Eu²⁺,Mn²⁺ radiationally coupled to the semiconductor ultraviolet radiation source;

Y₂O₃;

Eu³⁺,Bi³⁺ radiationally coupled to the semiconductor ultraviolet radiation source; and

at least one of (Sr,Ba,Ca)₅(PO₄)₃Cl;

Eu²⁺ and BaMg₂Al₁₆O₂₇;

Eu²⁺ radiationally coupled to the semiconductor ultraviolet radiation source;

wherein the composition is capable of absorbing ultraviolet source and converting the ultraviolet radiation into visible light;

and wherein the Y₂O₃;

Eu³⁺, Bi³⁺ is provided in a range between about 40% to about 80% by weight;

the Ca₈Mg(SiO₄)₄Cl;

Eu²⁺,Mn²⁺ is provided in a range between about 20% to about 50% by weight; and

the at least one of (Sr,Ba,Ca)₅(PO₄)₃C1;

Eu²⁺ and BaMg₂Al₁₆O₂₇;

Eu²⁺ is provided in a range between about 5% to about 25% by weight.

18. A light source comprising:

a semiconductor radiation source which emits radiation;

a transmissive body which contains a plurality of scattering particles, which scatter the radiation, formed adjacent to the semiconductor radiation source through which the radiation from the semiconductor radiation source propagates;

at least one luminescent material formed adjacent to the transmissive body, the at least one luminescent material converting the radiation emitted from the semiconductor radiation source to radiation of a different wavelength.

19. The light source of claim 18, wherein the semiconductor radiation source comprises a laser diode which emits radiation having a wavelength in the range of about 350-400 nm.

20. The light source of claim 19, wherein the plurality of scattering particles are dispersed within the transmissive body to scatter the radiation emitted from the laser diode to reduce optical saturation effects and physical damage of the luminescent material.

21. The light source of claim 20, wherein the scattering particles comprise at least one of TiO₂ and Al₂O₃.

22. The light source of claim 19, wherein the at least one phosphor comprises:

Y₂O₃;

Eu³⁺, Bi³⁺;

at least one of;

Ca₈Mg(SiO₄)₄Cl;

Eu²⁺,Mn²⁺;

Ba₂SiO₄;

Eu²⁺; and

(Ba,Sr)Al₂O₄;

Eu²⁺; and

at least one of;

(Ba,Sr,Ca)₅(PO₄)₃Cl;

Eu³⁺;

BaMg₂Al₁₆O₂₇;

Eu²⁺; and

BaMgAl₁₀O₁₇;

Eu²⁺.

23. The light source of claim 19, wherein the transmissive body comprises at least one of a glass material, a plastic material, and a silicone material which encapsulates the laser diode.

24. The light source of claim 20, wherein the at least one luminescent material comprises at least one phosphor formed on a surface of the transmissive body.

25. The light source of claim 20, wherein the at least one phosphor comprises Y₂O₃:

Eu³⁺,Bi³⁺.

26. The light source of claim 20, wherein the at least one phosphor comprises Ca₈Mg(SiO₄)₄Cl₂:

Eu²⁺,Mn²⁺.

27. The light source of claim 20, wherein the at least one phosphor comprises Ba₂SiO₄:

Eu²⁺.

28. The light source of claim 20, wherein the at least one phosphor comprises (Ba,Sr)Al₂O₄:

Eu²⁺.

29. The light source of claim 20, wherein the at least one phosphor comprises (Ba,Sr,Ca)₅(PO₄)₃Cl:

Eu²⁺.

30. The light source of claim 20, wherein the at least one phosphor comprises BaMgAl₁₀O₁₇:

Eu²⁺.

31. The light source of claim 20, wherein the at least one phosphor comprises BaMg₂Al₁₆O₂₇:

Eu²⁺.

32. A method of producing light comprising the steps of:

generating radiation having a wavelength in a range of about 350-400 nm with a laser diode;

scattering the radiation with a plurality of scattering particles disposed around the laser diode; and

converting at least a portion of the scattered radiation to a different wavelength with at least one phosphor.

33. The method of claim 32, wherein the scattered radiation is converted to white light.