RED LIGHT EMITTING GLASS CERAMIC AND PREPARATION METHOD THEREOF, AND LED/LD LIGHT EMITTING DEVICE

Abstract

The present invention provides a red light emitting glass ceramic and a preparation method thereof, and an LED/LD light emitting device. A.sub.2Al.sub.4Si.sub.5O.sub.18:Eu.sup.2+ cordierite of the red light emitting glass ceramic capable of realizing blue light excited red light emission is a crystal phase material, wherein A is at least one of Mg, Ca, Sr, Ba and Zn and at least comprises Mg. The present invention particularly provides the red light emitting glass ceramic taking a chemical formula A.sub.2Al.sub.4Si.sub.5O.sub.18:Eu.sup.2+ as a crystal phase. The present invention further provides a preparation method of the transparent glass ceramic. The glass ceramic comprising the crystal phase, with the chemical formula of Mg.sub.2Al.sub.4Si.sub.5O.sub.18:Eu.sup.2+, is excited by blue light to emit red light, the internal/external quantum efficiencies reaching up to 94.5%/70.6%, respectively.

Claims

1. A red light emitting glass ceramic, comprising a cordierite crystal phase with a chemical formula of A.sub.2Al.sub.4Si.sub.5O.sub.18:Eu.sup.2+, wherein A is at least one of Mg, Ca, Sr, Ba and Zn and at least comprises Mg.

2. The red light emitting glass ceramic according to claim 1, wherein a precursor for preparing the red light emitting glass ceramic is a glass matrix, and the glass matrix for preparing the red light emitting glass ceramic comprises the following components: 10-80 mol % of SiO.sub.2, 5-70 mol % of Al.sub.2O.sub.3, 5-70 mol % of MgO, 0-60 mol % of CaO, 0-60 mol % of SrO, 0-60 mol % of BaO, 0-60 mol % of ZnO, 0.01-10 mol % of Eu.sub.2O.sub.3, totalling 100 mol %, and the glass matrix at least comprises four raw materials: SiO.sub.2, Al.sub.2O.sub.3, MgO and Eu.sub.2O.sub.3.

3. A preparation method of the red light emitting glass ceramic according to claim 1, comprising the following steps: step (1) weighing the raw materials: SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO, SrO, BaO, ZnO and Eu.sub.2O.sub.3 in proportion of ingredient, heating the raw materials in a reducing atmosphere after the raw materials are subjected to mixing and even grinding, subjecting the raw materials to heat preservation to melt the raw materials to obtain melt liquid, and then cooling the melt liquid to obtain bulk transparent precursor glass; and step (2) heating the bulk transparent precursor glass obtained in step (1) in the reducing atmosphere, and subjecting the bulk transparent precursor glass to heat preservation to crystallize the bulk transparent precursor glass so as to obtain the red light emitting glass ceramic with the cordierite crystal phase.

4. The preparation method according to claim 3, wherein one or more of the raw materials MgO, CaO, SrO, BaO and ZnO is replaceable by carbonates MgCO.sub.3, CaCO.sub.3, SrCO.sub.3, BaCO.sub.3 and ZnCO.sub.3 corresponding to MgO, CaO, SrO, BaO and ZnO.

5. The preparation method according to claim 3, wherein the reducing atmosphere in step (1) is a nitrogen and hydrogen mixed gas, an argon and hydrogen mixed gas, a reduced C powder or CO, with a heating temperature being 1450-1700° C. and a heat preservation time being 30 min to 8 h; and the reducing atmosphere in step (2) is a nitrogen and hydrogen mixed gas, an argon and hydrogen mixed gas, a reduced C powder or CO, with a heating temperature being 700-1250° C. and a heat preservation time being 5 min to 12 h.

6. The preparation method according to claim 4, wherein the reducing atmosphere in step (1) is a nitrogen and hydrogen mixed gas, an argon and hydrogen mixed gas, a reduced C powder or CO, with a heating temperature being 1450-1700° C. and a heat preservation time being 30 min to 8 h; and the reducing atmosphere in step (2) is a nitrogen and hydrogen mixed gas, an argon and hydrogen mixed gas, a reduced C powder or CO, with a heating temperature being 700-1250° C. and a heat preservation time being 5 min to 12 h.

7. A red light emitting LED/LD light emitting device, comprising a package substrate, a blue light LED chip/a blue light LD diode and a fluorescent material capable of absorbing LED/LD blue light emission and emitting red light, wherein the red light emitting fluorescent material is the red light emitting glass ceramic according to claim 1.

8. A white light emitting LED/LD light emitting device, comprising a package substrate, a blue light LED chip/a blue light LD diode and a fluorescent material capable of absorbing LED/LD blue light emission and releasing yellow light or green light and a fluorescent material capable of releasing red light, wherein the red light releasing fluorescent material is the red light emitting glass ceramic according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 is an X-ray diffraction pattern of a red light emitting glass ceramic sample in an example 1.

[0042] FIG. 2 is excitation and emission spectra of a red light emitting glass ceramic sample in an example 1.

[0043] FIG. 3 is a tested quantum efficiency spectrum of a red light emitting glass ceramic sample in an example 1.

[0044] FIG. 4 is a luminous flux and luminous efficiency diagram dependent on a laser power density of a red light emitting glass ceramic sample in an example 1.

DESCRIPTION OF THE EMBODIMENTS

[0045] Further description of specific embodiments of the present invention in detail will be made below in combination with examples and drawings, but the implementation modes and protection scope of the present invention are not limited thereto.

EXAMPLE 1

[0046] Analytically pure SiO.sub.2, Al.sub.2O.sub.3, MgO and Eu.sub.2O.sub.3 powders were precisely weighed according to a proportion (molar ratio) of 40SiO.sub.2: 35Al.sub.2O.sub.3: 24MgO: 1Eu.sub.2O.sub.3 and were placed in an agate ball-milling pot, the powders were placed in an alumina crucible after the powders were evenly ground in the agate ball-milling pot, the powders were put in a tubular furnace where a nitrogen and hydrogen mixed gas was introduced, the powders were heated to 1450° C., and the powders were subjected to heat preservation for 1 h to melt the powders; then, a melt was subjected to furnace cooling to obtain precursor glass; and the bulk glass was heated to 1100° C. still in the nitrogen and hydrogen mixed atmosphere, and was subjected to heat preservation for 20 min to crystallize the bulk glass so as to obtain the red light emitting glass ceramic sample.

[0047] X-ray diffraction data indicates that an Mg.sub.2Al.sub.4Si.sub.5O.sub.18:Eu.sup.2+ micro crystal glass ceramic is prepared (as shown in FIG. 1). FIG. 2 is excitation and emission spectra of a sample at room temperature. The glass ceramic can be excited by near ultraviolet and blue light to emit light with a wavelength range of 500-850 nm. The emitting color is red, corresponding to energy level transition of Eu.sup.2+: 5d.sub.1.fwdarw.4f. The light emitting internal/external quantum efficiencies are respectively 94.5%/70.6% (FIG. 3). The performance of the apparatus is tested by coupling the red light emitting sample with blue light laser, and the maximum luminous flux and the maximum luminous efficiency are respectively about 274 lm and about 54 lm/W (FIG. 4).

EXAMPLE 2

[0048] Analytically pure SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO and Eu.sub.2O.sub.3 powders were precisely weighed according to a proportion (molar ratio) of 40SiO.sub.2: 30Al.sub.2O.sub.3: 20MgO: 9CaO: 1Eu.sub.2O.sub.3 and were placed in an agate ball-milling pot, the powders were placed in an alumina crucible after the powders were evenly ground in the agate ball-milling pot, the powders were put in a tubular furnace where a nitrogen and hydrogen mixed gas was introduced, the powders were heated to 1700° C., and the powders were subjected to heat preservation for 8 h to melt the powders; then, a melt was subjected to furnace cooling to obtain precursor glass; and the bulk glass was heated to 700° C. still in the nitrogen and hydrogen mixed atmosphere, and was subjected to heat preservation for 12 h to crystallize the bulk glass so as to obtain the red light emitting glass ceramic sample.

[0049] After the test, the Mg.sub.1.5Ca.sub.0.5Al.sub.4Si.sub.5O.sub.18:Eu.sup.2+ nano crystal glass ceramic is prepared, the light emitting internal/external quantum efficiencies being respectively 90%/70%. The performance of the apparatus is tested by coupling the red light emitting sample with blue light laser, and the maximum luminous flux and the maximum luminous efficiency are respectively about 250 lm and about 52 lm/W.

EXAMPLE 3

[0050] Analytically pure SiO.sub.2, Al.sub.2O.sub.3, MgO, BaO and Eu.sub.2O.sub.3 powders were precisely weighed according to a proportion (molar ratio) of 40SiO.sub.2: 30Al.sub.2O.sub.3: 20MgO: 9BaO: 1Eu.sub.2O.sub.3 and were placed in an agate ball-milling pot, the powders were placed in an alumina crucible after the powders were evenly ground in the agate ball-milling pot, the powders were put in a tubular furnace where a nitrogen and hydrogen mixed gas was introduced, the powders were heated to 1700° C., and the powders were subjected to heat preservation for 30 min to melt the powders; then, a melt was subjected to furnace cooling to obtain precursor glass; and the bulk glass was heated to 1000° C. still in the nitrogen and hydrogen mixed atmosphere, and was subjected to heat preservation for 4 h to crystallize the bulk glass so as to obtain the red light emitting glass ceramic sample.

[0051] After the test, the Mg.sub.1.5Ba.sub.0.5Al.sub.4Si.sub.5O.sub.18:Eu.sup.2+ nano crystal glass ceramic is prepared, the light emitting internal/external quantum efficiencies being respectively 96%/75%. The performance of the apparatus is tested by coupling the red light emitting sample with blue light laser, and the maximum luminous flux and the maximum luminous efficiency are respectively about 260 lm and about 45 lm/W.

EXAMPLE 4

[0052] Analytically pure SiO.sub.2, Al.sub.2O.sub.3, MgO, SrO and Eu.sub.2O.sub.3 powders were precisely weighed according to a proportion (molar ratio) of 40SiO.sub.2: 30Al.sub.2O.sub.3: 20MgO: 9SrO: 1Eu.sub.2O.sub.3 and were placed in an agate ball-milling pot, the powders were placed in an alumina crucible after the powders were evenly ground in the agate ball-milling pot, the powders were put in a tubular furnace where a nitrogen and hydrogen mixed gas was introduced, the powders were heated to 1550° C., and the powders were subjected to heat preservation for 6 h to melt the powders; then, a melt was subjected to furnace cooling to obtain precursor glass; and the bulk glass was heated to 900° C. still in the nitrogen and hydrogen mixed atmosphere, and was subjected to heat preservation for 10 h to crystallize the block glass so as to obtain the red light emitting glass ceramic sample.

[0053] After the test, the Mg.sub.1.6Sr.sub.0.4Al.sub.4Si.sub.5O.sub.18:Eu.sup.2+ nano crystal glass ceramic is prepared, the light emitting internal/external quantum efficiencies being respectively 92%/65%. The performance of the apparatus is tested by coupling the red light emitting sample with blue light laser, and the maximum luminous flux and the maximum luminous efficiency are respectively about 250 lm and about 55 lm/W.

EXAMPLE 5

[0054] Analytically pure SiO.sub.2, Al.sub.2O.sub.3, MgO, ZnO and Eu.sub.2O.sub.3 powders were precisely weighed according to a proportion (molar ratio) of 40SiO.sub.2: 30Al.sub.2O.sub.3: 20MgO: 9ZnO: 1Eu.sub.2O.sub.3 and were placed in an agate ball-milling pot, the powders were placed in an alumina crucible after the powders were evenly ground in the agate ball-milling pot, the powders were put in a tubular furnace where a nitrogen and hydrogen mixed gas was introduced, the powders were heated to 1500° C., and the powders were subjected to heat preservation for 5 h to melt the powders; then, a melt was subjected to furnace cooling to obtain precursor glass; and the bulk glass was heated to 1050° C. still in the nitrogen and hydrogen mixed atmosphere, and was subjected to heat preservation for 2 h to crystallize the block glass so as to obtain the red light emitting glass ceramic sample.

[0055] After the test, the Mg.sub.1.6Zn.sub.0.4Al.sub.4Si.sub.5O.sub.18:Eu.sup.2+ nano crystal glass ceramic is prepared, the light emitting internal/external quantum efficiencies being respectively 85%/65%. The performance of the apparatus is tested by coupling the red light emitting sample with blue light laser, and the maximum luminous flux and the maximum luminous efficiency are respectively about 220 lm and about 45 lm/W.

[0056] The above is merely preferred embodiments of the present invention and is not used to limit the present invention. For those skilled in the art, various alternations and changes can be made on the present invention. Any modification, equivalent replacement, improvement, etc.

[0057] made within the spirit and principle of the present invention shall be regarded as within the protection scope of the present invention.