White LED device having LED chips directly driven by alternating current

• US 9,185,761 B2
• Filed: 03/01/2011
• Issued: 11/10/2015
• Est. Priority Date: 11/09/2010
• Status: Expired due to Fees

• Current Assignee: Changchun Institute of Applied Chemistry Chinese Academy of Sciences, Sichuan Sunfor Light Co. Ltd.
• Original Assignee: Changchun Institute of Applied Chemistry Chinese Academy of Sciences, Sichuan Sunfor Light Co. Ltd.
• Inventors: Zhang, Hongjie, Zhang, Ming, Li, Chengyu, Zhao, Kun, Li, Dongming, Zhang, Li
• Primary Examiner(s): Wells, Kenneth B
• Application Number:
  US13/883,832
• Publication Number:
  US 20130221870A1
• Time in Patent Office: 1,715 Days
• Field of Search: 313/498, 313501-503, 257/98, 257/100, 257/103
• US Class Current: 1/1
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/42 Antiparallel configurations

Abstract

An Alternate Current (AC) white Light-Emitting Diode (LED) device is provided, which belongs to the technical field of white LED manufacturing. The problem to be solved by the present invention is to low-costly overcome a series of deficiencies such as the stroboflash of an AC driven LED, and the heat dissipation difficulty caused by an integrated packaging of multiple LEDs. A white LED unit includes an LED chip and a light emitting material that can emit light when being excited by the LED chip. The luminous lifetime of the light emitting material is 1-100 ms. The LED chip only comprises one PN junction. The light emitted by the LED chip is mixed with the light emitted by the light emitting material to form white light. The white LED unit is driven by AC with a frequency not more than 100 Hz. The white LED device of prevent invention uses the single PN junction chip, rather than the prior integrated packaged AC multi-LED chip.

Claims

1. A white Light-Emitting Diode (LED) device, said LED device comprising:

an LED chip and a light emitting material capable of emitting light when excited by said LED chip, said LED chip comprising a single light emitting PN junction, and wherein said LED chip is driven directly by Alternating Current (AC) with a frequency of not more than 100 Hz, wherein a luminous lifetime of the light emitting material is 1 to 100 ms, wherein a luminous brightness under a non-constant current condition is compensated for through afterglow of the light emitting material, and wherein light emitted by the LED chip is mixed with light emitted by the light emitting material to form white light, wherein said light emitting material is selected from the group consisting of (1) a combination of Zn₂P₂O₇;

Tm³⁺; and

Zn₃(PO₄)₂;

Mn²⁺, Ga³⁺;

(2) CaAl₂O₄;

Dy³⁺;

(3) a combination of Sr₂P₂O₇;

Eu²⁺, Y³⁺;

Sr₄Al₁₄O₂₅;

Eu²⁺, Dy³⁺, B³⁺;

Ca₄O(PO₄)₂;

Eu²⁺; and

Zn₃(PO₄)₂;

Mn²⁺, Ga³⁺;

(4) a combination of Sr₂P₂O₇;

Eu²⁺, Y³⁺;

Sr₄Al₁₄O₂₅;

Eu²⁺; and

Y₂O₂S;

Eu³⁺;

(5) a combination of SrMg₂(PO₄)₂;

Eu²⁺, Gd³⁺; and

Ca₄O(PO₄)₂;

Eu²⁺;

(6) a combination of Sr₄Al₁₄O₂₅;

Eu²⁺; and

Y₂O₂S;

Eu³⁺;

(7) a combination of SrAl₂O₄;

Eu²⁺, B³⁺; and

CaS;

Eu²⁺;

(8) a combination of Y₂O₂S;

Mg²⁺, Ti³⁺; and

SrAl₂O₄;

Eu²⁺.

2. The white LED device according to claim 1, the wherein said LED chip is driven by Alternating Current (AC) with a frequency of 50 to 60 Hz.

3. The white LED device according to claim 2, wherein said luminous lifetime of the light emitting material is 10 to 30 ms.

4. The white LED device according to claim 1, wherein said light emitting material is selected from the group consisting of (1) 45 wt % Zn₂P₂O₇:

Tm³⁺; and

55 wt % Zn₃(PO₄)₂;

Mn²⁺, Ga³⁺;

(2) CaAl₂O₄;

Dy³⁺;

(3) 15 wt % Sr₂P₂O₇;

Eu²⁺, Y³⁺;

30 wt % Sr₄Al₁₄O₂₅;

Eu²⁺, Dy³⁺, B³⁺;

15 wt % Ca₄O(PO₄)₂;

Eu²⁺; and

40 wt % Zn₃(PO₄)₂;

Mn²⁺, Ga³⁺;

(4) 10 wt % Sr₂P₂O₇;

Eu²⁺, Y³⁺;

30 wt % Sr₄Al₁₄O₂₅;

Eu²⁺; and

60 wt % Y₂O₂S;

Eu³⁺;

(5) 50 wt % SrMg₂(PO₄)₂;

Eu²⁺, Gd³⁺; and

50 wt % Ca₄O(PO₄)₂;

Eu²⁺;

(6) 40 wt % Sr₄Al₁₄O₂₅;

Eu²⁺; and

60 wt % Y₂O₂S;

Eu³⁺;

(7) 30 wt % SrAl₂O₄;

Eu²⁺, B³⁺; and

70 wt % CaS;

Eu²⁺; and

(8) 60 wt % Y₂O₂S;

Mg²⁺, Ti³⁺; and

40 wt % SrAl₂O₄;

Eu²⁺.

5. The white LED device according to claim 2, wherein said light emitted by the LED chip is ultraviolet light in a range of 200 nm to 380 nm or visible light in a range of 380 nm to 780 nm.

6. The white LED device according to claim 1, further comprising a driving circuit, wherein said driving circuit comprises a circuit selected from the group consisting of a unidirectional series circuit, a reverse parallel circuit and a bridge rectifier circuit.

7. The white LED device according to claim 6, further comprising a light guide covering layer.

8. The white LED device according to claim 7, wherein the light guide covering layer is doped with particles of non-light-emitting material with a diameter less than 5 μ

m.

9. The white LED device of claim 1, further comprising an AC driving circuit and at least one white LED chip, wherein said driving circuit comprises combinations of a unidirectional series circuit, a reverse parallel circuit and a bridge rectifier circuit.

10. The white LED device of claim 6, wherein said driving circuit is a reverse parallel circuit and wherein every diode used in said driving circuit is a LED.

11. The white LED device of claim 6, wherein said driving circuit is a bridge rectifier circuit and wherein every diode used in said driving circuit is a LED.

12. A method of generating white light using a light emitting diode (LED) chip, said method comprising:

providing a LED chip comprising a single PN junction;

associating said LED chip with a light emitting material which is capable of emitting light when excited by said LED chip, and wherein said light emitting material comprises a luminous lifetime of 1 to 100 ms and wherein said light emitting material comprises a luminous brightness under a non-constant current condition that is compensated for by an afterglow of said light emitting material; and

directly driving said LED chip using an alternating current (AC) with a frequency of no more than 100 Hz,

wherein said light emitting material is selected from the group consisting of (1) a combination of Zn₂P₂O₇;

Tm³⁺; and

Zn₃(PO₄)₂;

Mn²⁺, Ga³⁺;

(2) CaAl₂O₄;

Dy³⁺;

(3) a combination of Sr₂P₂O₇;

Eu²⁺, Y³⁺;

Sr₄Al₁₄O₂₅;

Eu²⁺, Dy³⁺, B³⁺;

Ca₄O(PO₄)₂;

Eu²⁺; and

Zn₃(PO₄)₂;

Mn²⁺, Ga³⁺;

(4) a combination of Sr₂P₂O₇;

Eu²⁺, Y³⁺;

Sr₄Al₁₄O₂₅;

Eu²⁺; and

Y₂O₂S;

Eu³⁺;

(5) a combination of SrMg₂(PO₄)₂;

Eu²⁺, Gd³⁺; and

Ca₄O(PO₄)₂;

Eu²⁺;

(6) a combination of Sr₄Al₁₄O₂₅;

Eu²⁺; and

Y₂O₂S;

Eu³⁺;

(7) a combination of SrAl₂O₄;

Eu²⁺, B³⁺; and

CaS;

Eu²⁺;

(8) a combination of Y₂O₂S;

Mg²⁺, Ti³⁺; and

SrAl₂O₄;

Eu²⁺.

13. The method of claim 12, wherein said step of exciting said LED chip comprises using AC with a frequency of 50 to 60 Hz.

14. The method of claim 13 wherein said luminous lifetime of the light emitting material is 10 to 30 ms.

15. The method of claim 12, wherein said light emitting material is selected from the group consisting of (1) 45 wt % Zn₂P₂O₇:

Tm³⁺; and

55 wt % Zn₃(PO₄)₂;

Mn²⁺, Ga³⁺;

(2) CaAl₂O₄;

Dy³⁺;

(3) 15 wt % Sr₂P₂O₇;

Eu²⁺, Y³⁺;

30 wt % Sr₄Al₁₄O₂₅;

Eu²⁺, Dy³⁺, B³⁺;

15 wt % Ca₄O(PO₄)₂;

Eu²⁺; and

40 wt % Zn₃(PO₄)₂;

Mn²⁺, Ga³⁺;

(4) 10 wt % Sr₂P₂O₇;

Eu²⁺, Y³⁺;

30 wt % Sr₄Al₁₄O₂₅;

Eu²⁺; and

60 wt % Y₂O₂S;

Eu³⁺;

(5) 50 wt % SrMg₂(PO₄)₂;

Eu²⁺, Gd³⁺; and

50 wt % Ca₄O(PO₄)₂;

Eu²⁺;

(6) 40 wt % Sr₄Al₁₄O₂₅;

Eu²⁺; and

60 wt % Y₂O₂S;

Eu³⁺;

(7) 30 wt % SrAl₂O₄;

Eu²⁺, B³⁺; and

70 wt % CaS;

Eu²⁺;

(8) 60 wt % Y₂O₂S;

Mg²⁺, Ti³⁺; and

40 wt % SrAl₂O₄;

Eu²⁺.

16. The method of claim 12, wherein said light emitted by the LED chip is ultraviolet light in a range of 200 nm to 380 nm or visible light in a range of 380 nm to 780 nm.

17. The method of claim 12, further comprising the step of covering said LED chip and said light emitting material with a light guide covering layer.

18. The method of claim 17, wherein said step of covering said LED chip and said light emitting material comprises doping said light guide covering layer with particles of non-light-emitting material with a diameter less than 5 μ

m.