TWI383034B - Two-phase silicate-based yellow phosphor - Google Patents

Two-phase silicate-based yellow phosphor Download PDF

Info

Publication number
TWI383034B
TWI383034B TW95138585A TW95138585A TWI383034B TW I383034 B TWI383034 B TW I383034B TW 95138585 A TW95138585 A TW 95138585A TW 95138585 A TW95138585 A TW 95138585A TW I383034 B TWI383034 B TW I383034B
Authority
TW
Taiwan
Prior art keywords
sio
phosphor
m1
phase
m2
Prior art date
Application number
TW95138585A
Other languages
Chinese (zh)
Other versions
TW200728434A (en
Inventor
Yi-Qun Li
Yi Dong
Shifan Cheng
Dejie Tao
Ning Wang
Original Assignee
Intematix Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US11/258,679 priority Critical patent/US7655156B2/en
Priority to US11/269,953 priority patent/US7575697B2/en
Priority to US11/417,690 priority patent/US7601276B2/en
Application filed by Intematix Corp filed Critical Intematix Corp
Publication of TW200728434A publication Critical patent/TW200728434A/en
Application granted granted Critical
Publication of TWI383034B publication Critical patent/TWI383034B/en

Links

Classifications

    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00Energy efficient lighting technologies
    • Y02B20/16Gas discharge lamps, e.g. fluorescent lamps, high intensity discharge lamps [HID] or molecular radiators
    • Y02B20/18Low pressure and fluorescent lamps
    • Y02B20/181Fluorescent powders

Description

Two-phase yellow phosphor based on citrate

The total system of the present invention relates to a two-phase bismuth silicate-based photoluminescent material. More specifically, embodiments of the present invention relate to a yellow-emitting phosphor comprising two bismuth-based phases, the phosphor in a high-brightness white LED illumination system, an LCD display panel, a plasma display panel, and a yellow There are applications in light lighting systems.

White LEDs are well known in the industry and relatively recent innovations. Until the development of LEDs that emit light in the blue/ultraviolet region of the electromagnetic spectrum, it is possible to make LED-based white light sources. Economically, white LEDs have the potential to replace incandescent light sources (bulbs), especially when production costs are reduced and technology is further developed. In particular, it is believed that white LEDs have the potential to outperform incandescent bulbs in terms of lifetime, robustness and efficiency. For example, LED-based white light illumination sources are expected to meet industry standards of 100,000 hours of operating life and 80 to 90% efficiency. High-brightness LEDs have had a substantial impact on areas such as traffic light signals, replacing incandescent lamps, and so it is not surprising that they will soon meet the general lighting requirements in home and business and other everyday applications.

There are several general methods for fabricating white light illumination systems based on luminescent phosphors. To date, most white LED commercial products have been manufactured according to the method shown in Figure 1, in which light from a source of light has an effect on the color output of white light illumination. Referring to system 10 of Figure 1, a radiation source 11 (which can be an LED) emits light rays 12, 15 located in the visible portion of the electromagnetic spectrum. Light rays 12 and 15 are the same light, but are shown as two separate beams for illustrative purposes. A portion of the light emitted from the radiation source 11, i.e., the light 12, excites a phosphor 13 which, upon absorption of energy from the radiation source 11, emits the photoluminescent material of the light 14. The light 14 can be a substantially monochromatic light in the yellow region of the spectrum, or it can be a combination of green and red, green and yellow, or yellow and red. The radiation source 11 also emits blue light in visible light that is not absorbed by the phosphor 13; it is the visible blue light 15 shown in FIG. It can be seen that the blue light 15 is mixed with the yellow light 14 to provide the desired white light illumination 16 as shown in the figure.

Alternatively, an updated method has used a source of non-visible radiation that emits ultraviolet (UV) light. This concept is illustrated in Figure 1B, which illustrates an illumination system that includes a source of radiation that emits non-visible light such that light from the source of radiation does not substantially affect the light produced by the illumination system. Referring to FIG. 1B, a substantially invisible line is emitted from the radiation source 21 in the form of rays 22, 23. Light 22 is of the same characteristic as light 23, but uses two different reference numerals to illustrate the point that light 22 can be used to excite a phosphor, such as phosphor 24 or 25, but light 23 from radiation source 21 does not strike phosphorescence. The body does not affect the color output 28 from the (etc.) phosphor, because the light 23 is invisible to the human eye.

There is a need for an improvement over the prior art citrate-based yellow phosphor, wherein the improvement is at least partially manifested by the conversion efficiency of the blue photoexcitation light into a desired yellow light output from the phosphor that is equal to or greater than the prior art. its. It is also desirable for the phosphor to have temperature stability up to 200 ° C and enhanced color rendering. Moreover, it is critical to increase manufacturing yield to provide a yellow phosphor having broad and consistent excitation efficiencies in the wavelength range from about 400 nanometers to about 480 nanometers. The desired yellow phosphor with overall high performance and low cost can be used with the same blue LED to produce high brightness white light, the color output does not change with temperature and its color mixing produces the desired consistent color temperature and color rendering index.

The present invention relates to a yellow phosphor having two different phases in its composition, which are generally represented by the formula (M1) 2 SiO 4 and (M2) 3 SiO 5 , wherein each of M1 and M2 can be rare earth metal. When the phosphor of the present invention is excited by a radiation source that emits radiation between about 220 nanometers and about 530 nanometers, it has a peak emission intensity at a wavelength between about 555 nanometers and about 580 nanometers. The yellow phosphor of the present invention is configured to absorb UV light to visible light having a wavelength of less than about 530 nm and can be excited by approximately uniform emission intensity from light having a wide range of wavelengths between about 360 nm and about 520 nm.

Specifically, the yellow phosphor of the present invention comprises a compound having a stoichiometric relationship of two phases, preferably a phthalate, having at least one divalent alkaline earth metal element M1 or M2 (which is Mg, Ca, Ba or Zn). The stoichiometric relationship is generally represented by the formula a[Sr x (M1) 1 - x ] z SiO 4 ●(1-a)[Sr y (M2) 1 - y ] u SiO 5 :Eu 2 + D, where M1 and M2 is at least one divalent metal selected from the group consisting of Ba, Mg, Ca, and Zn. The dot in the middle of the formula indicates that the SiO 4 and SiO 5 moieties in the compound form two distinct phases in the material. The values of a, x, y, z, and u are in the following relationship: 0.6 a 0.85; 0.3 x 0.6; 0.85 y 1;1.5 z 2.5; and 2.6 u 3.3. The amounts of ruthenium (Eu) and anion D are each between about 0.001 and about 0.5. The anion D is selected from the group consisting of F, Cl, Br, S, and N, and it specifically replaces the oxygen anion in the crystal lattice of any of the two phases of the two-phase phosphor. The phosphors are configured to emit visible light having a peak emission wavelength between about 555 nm and 580 nm.

In another embodiment of the invention, a yellow phosphor can be used in a white LED. The white light illumination system includes a radiation source configured to emit radiation having a wavelength greater than about 280 nm; and a two-phase yellow phosphor dominated by niobate, the phosphor configured to absorb radiation from the radiation source At least a portion of the light is emitted with a peak intensity having a wavelength between 550 nm and about 580 nm. The yellow phosphor has the formula a[Sr x (M1) 1 - x ] z SiO 4 ● (1-a) [Sr y (M2) 1 - y ] u SiO 5 :Eu 2 + D, where M1, M2 x, y, z, and u are as defined above.

The method of synthesizing the yellow phosphor of the present invention includes a sol-gel method, a solid reaction method, and a coprecipitation method. Such methods generally involve dissolving the metal and metalloid salts in a water-based solution and allowing all components to precipitate together. The precipitate may comprise a solution of a hydroxylate and a carboxylate of the metals mixed at the atomic level. The solution can include a halogen dopant that can replace the oxygen on the lattice points.

An exemplary coprecipitation method comprises: a) dissolving Sr(NO 3 ) 3 , (M1)(NO 3 ) 2 and (M2)(NO 3 ) 2 in water; b) dissolving Eu 2 O 3 in nitric acid ; c) dissolving SrF 2 in nitric acid; d) mixing the solution produced by steps a), b) and c); e) adding (CH 3 O) 4 Si to the solution produced in step d), And then adding an acid to the mixture to initiate precipitation; f) adjusting the pH of the mixture of step e) to about 9; g) drying the reaction product of step f), and then calcining the reaction product Decomposing the precipitate; and h) sintering the precipitate of step g) under a reducing atmosphere.

The excitation spectrum shows that the yellow phosphor of the present invention can effectively emit fluorescence when excited at a wavelength of between about 200 and 540 nm. The yellow phosphors of the present invention provide emission characteristics superior to those of prior art phosphors, including both higher luminous efficiency and better temperature stability, as well as emission uniformity over a larger range of excitation wavelengths. The excitation wavelengths are between about 400 nanometers and about 500 nanometers.

In this specification, the effect of changing the ratio of alkaline earth metal to cerium in the host lattice, the type of alkaline earth metal, the content of Eu activator, and the role of the halogen dopant are discussed.

The novel phosphor of the present invention comprises a compound based on a dibasic citrate. It can be used in many applications, including components for white LED systems, yellow lighting systems, and color display panels, including components for RGB (red, green, blue) backlight systems for plasma display panels. The phosphors of the present invention have particular applications in high power LED packages that operate at higher junction temperatures.

The various embodiments of the two-phase citrate-based phosphor of the present invention will be illustrated in the following order: First, an overview of the two-phase citrate-based novel composition will be outlined, followed by a detailed description of the citric acid. The crystalline nature of the salt host lattice changes the effect of the relative amounts of alkaline earth metals and strontium in the lattice and the relative amounts of different alkaline earth metals. The activator divalent europium (Eu 2 + ) in at least one phase of the composition is then discussed and a dopant D comprising one or more of the elements F, Cl, Br, S and N is disclosed. Of particular importance is the fact that at least some of the dopant atoms are located at the lattice point of the oxygen atom of the ceric acid host crystal.

Further discussing the advantages of providing a two-phase bismuthate-based system of the present invention, including but not limited to a plurality of excitation energies available for the two (or more) phase phosphors, the two (or more) The enhanced temperature stability of the phase phosphor and the desired emission spectrum of the one or two (or more) phase phosphor systems.

Finally, the application of the two-phase phosphor system in white LEDs and color display panels will be covered, including the types of excitation sources available, and examples of other known phosphors that can be used with the two-phase system of the present invention.

Novel multi-phase citrate-based phosphor system in accordance with an embodiment of the present invention

The novel phosphor composition of the embodiments of the present invention has at least two phases based on citrate in the composition, wherein the first phase may have the same crystal structure as (M1) 2 SiO 4 and the second The phase may have the same crystal structure as (M2) 3 SiO 5 . Those skilled in the art will appreciate that the two citrate phases are exemplary; the present invention also encompasses many other phases, and the relative amounts of different citrate phases that work together define these novel attributes. .

In this context, M1 and M2 are each usually an alkaline earth metal, but M1 and M2 may also be other elements. Therefore, each of M1 and M2 is defined herein as being selected from the group consisting of Sr, Ba, Mg, Ca, and Zn. At least one phase of the composition contains Mg at a level of or equal to about 0.0001% by weight.

The phosphor composition of the present invention can be activated by divalent europium (Eu 2 + ), however, those skilled in the art will also appreciate that divalent europium (Eu 2 + ) is not the only activator that can be used to activate the phosphor composition.

At least one of the phases of the composition contains a halogen-free dopant D. When the dopant D is halogen, it may be any of F, Cl or Br. However, this does not mean that the dopant D must be halogen or special halogen; in fact, the dopant D may also include the elements S and N, and may be a combination of a halogen and S and/or N. In certain embodiments, at least some of the dopant D atoms of the phosphor composition are located on the oxygen atom lattice point of the bismuth silicate main crystal, wherein again the citrate host lattice comprises (but not limited to) structures such as SiO 4 , SiO 5 , Si 2 O 5 , Si 3 O 8 , SiO 4 , Si 2 O 7 and Si 2 O 8 , wherein the amount of the alkaline earth metal instead of lanthanum depends on the valence thereof.

In an embodiment of the invention, a novel two-phase phosphor of the invention can generally be described as a formula a[Sr x (M1) 1 - x ] z SiO 4 ● (1-a) [Sr y (M2) 1 - y u SiO 5 :Eu 2 + D, wherein the symbol between the SiO 4 moiety and the SiO 5 moiety of the formula is intended to indicate a separate phase. This formula is exemplary since any two citrate phases may have been selected. In the exemplary expressions shown above, each of M1 and M2 is at least one divalent metal selected from the group consisting of Ba, Mg, Ca, and Zn.

Regardless of its citrate structure, the phosphors of the embodiments of the present invention do not necessarily have to be stoichiometric in their chemical formulas, meaning that the various elements of the formula of the compound do not necessarily have to be an integer value relationship. For example, the formula a[Sr x (M1) 1 - x ] z SiO 4 ●(1-a)[Sr y (M2) 1 - y ] u SiO 5 :Eu 2 + D in x, y and z values Can meet the following relationship, of which 0.6 a 0.85; 0.3 x 0.6; 0.85 y 1;1.5 z 2.5; and 2.6 u 3.3.

The two-phase material of the present invention can be synthesized by two routes: (1) mixing the raw material component precursors in the desired composition of the two citrate phases and treating the precursor by a liquid phase reaction or a solid phase reaction and sintering (2) independently processing the two-phase material and mixing the final two-phase material by mechanical mixing.

As taught by G. Blasse et al. in Philips Research Reports, Vol. 23, Volume 1, pages 1 to 120, the host lattice in a ruthenium-activated phosphor may belong to the system Me 2 SiO 4 , where Me is Sr or Ba, in this case the phosphor has a K 2 SO 4 -like or Me 3 SiO 5 crystal structure, wherein Me is any one of Ca, Sr or Ba, wherein the phosphor has a crystal structure (or is associated with the crystal structure) ) Cs 3 CoCl 5 . The exemplary x-ray diffraction pattern shown in Figure 2A shows that the host lattice of the phosphor of the present invention is also crystalline.

Referring to FIG. 2A, there is shown a comparison between the (M2) 3 SiO 5 type compound, the two-phase composition containing the M 3 SiO 5 and the M 2 SiO 4 type compound, and the x-ray diffraction pattern of the (M1) 2 SiO 4 type compound. . X- ray diffraction pattern (M2) 3 SiO 5 as a compound of the display in the top curve of FIG. 2A, and the actual measured Sr-based compound of 3 Eu 0. 6 Si 1. 0 2 O 5 F 0. 1 3 . (M1) 2 SiO 4 type compound is the lowermost curve in Fig. 2, the actual compound system (Sr 1 . 0 2 5 Ba 0 . 9 2 5 Mg 0 . 0 5 )Eu 0 . 0 6 Si 1 . 0 3 O 4 F 0 . 1 2 .

The middle curve of Fig. 2A is an x-ray diffraction pattern of a two-phase citrate-based material whose general properties can be represented by the formula (M1) 2 SiO 4 ● (M2) 3 SiO 5 , wherein dots indicate The distinction between two phases of material. More specifically, the two-phase phosphor may be represented by the formula a(Sr x M1 1 - x ) z SiO 4 ●(1-a)(Sr y M2 1 - y ) u SiO 5 :Eu 2 + D, wherein In this case, the example phosphorescent system is 0.72 [(Sr 1 . 0 2 5 Ba 0 . 9 2 5 Mg 0 . 0 5 )Eu 0 . 0 6 Si 1 . 0 3 O 4 F 0 . 1 2 ] ● 0.28 ( Sr 3 Eu 0 . 6 Si 1 . 0 2 O 5 F 0 . 1 3 ). Of course, those skilled in the art should understand that in this case the term means a=0.72; (1-a)=0.28; M1 includes all alkaline earth metals Sr, Ba and Mg, while M2 is only Sr and is doped. The impurity D is fluorine.

A comparison of the three x-ray diffraction (XRD) patterns in Figure 2A indicates that all three samples are crystalline. Although not wishing to be bound by any particular theory, it is believed that (M1) 2 SiO 4 can exhibit a peak consistent with the structure of the strontium ruthenate Sr 2 SiO 4 (orthogonal crystal structure, space group Pnma), and (M2) 3 SiO 5 can show a peak consistent with the structure of another strontium ruthenate Sr 3 SiO 5 (quadrilateral crystal structure, space group P4/ncc). The peak position of the biphasic phosphor of the present invention may be slightly shifted or not moved along the 2θ axis due to the substitution of yttrium and/or magnesium in the actual phosphor.

2B shows an x-ray diffraction pattern of an exemplary two-phase phosphor synthesized by two different methods: 1) in one method, each phase in the respective phases is coprecipitated, calcined, and sintered, respectively. After each phase of the two phases is sufficiently treated, it is mixed; and 2) the two are synthesized in the liquid phase at the same time, and co-precipitated, calcined and sintered together. The sample prepared by the method 1) in Fig. 2B is labeled as "mechanical mixing after separate sintering", and the sample prepared by the method 2) is identified as "simultaneous precipitation".

For the two samples shown in Fig. 2B, the peaks and their positions are substantially the same, thus indicating that the two-phase (M1) 2 SiO 4 and (M2) 3 SiO 5 systems are respectively formed in a liquid phase.

Alkaline soil components M1 and M2 in SiO 4 And SiO 5 Effect in the citrate phase

The following sections discuss the effects of alkaline earth components M1 and M2 in (M1) 2 SiO 4 and (M2) 3 SiO 5 citrate phases, respectively.

Among other methods, the optical properties of the (M1) 2 SiO 4 phase can be controlled by adjusting the ratio of any other element to the amount of lanthanum, wherein the M1 system 锶 (Sr) plus another alkaline earth element such as magnesium (Mg), Calcium (Ca), barium (Ba) or a transition metal element such as zinc (Zn) or any combination thereof or any combination thereof. An exemplary data set for practicing an embodiment of the inventive concept is set forth in U.S. Patent Application Serial No. 11/269,953, filed on Nov. 8, 2005, entitled "Silicate-based green phosphors" Incorporated herein by reference.

Three kinds of green phosphor (having the formula (Sr 0 2 Ba 0 8) 2 SiO 4: Eu 2 + F by emitting at about 522 nanometers; (Sr 0 3 Ba 0 7 ) 2 SiO 4:.... Eu 2 + F emission at about 525 nm; and (Sr 0 4 Ba 0 6. .) 2 SiO 4: Eu 2 + F at about 532 nm at an emission) of the emission spectrum of U.S. Patent application No. 11 in / 269,953 Compared with the emission spectrum of more phosphors emitting light in the yellow region of the spectrum, the yellow phosphor based on citrate has the formula (Sr 0 . 7 Ba 0 . 3 ) 2 SiO 4 :Eu 2 + F. The yellow phosphor illuminates at about 540 nm. The phosphors are excited with a blue LED that emits light at about 450 nm.

The inventors of the present invention have revealed in previous studies that the wavelength position at which the peak emission occurs in the (Sr 1 - x Ba x ) 2 SiO 4 phosphor system is from green at 500 nm (in this case, x = 1, in other words, at this time) The alkali metal system contained 100% Ba) became yellow at 580 nm (in this case, x = 0 (100% Sr)). When Ba increases from 0 to about 90%, the conversion efficiency of the same light source at 450 nm also shows a continuous increase. The peak emission wavelength of 545 nm obtained when the ratio of Ba to Sr is 0.3 to 0.7 is close to the YAG:Ce peak emission wavelength.

The same four kinds of phosphors (Sr 0 . 2 Ba 0 . 8 ) 2 SiO 4 :Eu 2 + F, (Sr 0 . 3 Ba 0 . 7 ) 2 SiO 4 :Eu 2 + F, (Sr 0 . 4 Ba 0 . 6) 2 SiO 4: Eu 2 + F and (Sr 0 7 Ba 0 3) 2 SiO 4:.. Eu 2 + F group of the excitation spectrum is shown in U.S. Patent application No. 11 / 269,953. Those skilled in the art will appreciate that an "excitation spectrum" is actually an emission spectrum in which the intensity of the emitted light is measured as a function of the wavelength of the excitation radiation. In other words, the light emitted from the phosphor is measured at a particular wavelength and the wavelength is the wavelength of the radiation that is introduced into the scanned phosphor. The wavelength selected in this series of experiments is the wavelength at which the phosphor emits the strongest emission when excited at 450 nm.

In a specific example of U.S. Patent Application Serial No. 11/269,953, the detector used in the experiment is set to measure the emission of (Sr 0 . 2 Ba 0 . 8 ) 2 SiO 4 :Eu 2 + F phosphor. The intensity of the 522 nm light is due to the strongest emission wavelength of the 522 nm when the (Sr 0 . 2 Ba 0 . 8 ) 2 SiO 4 :Eu 2 + F phosphor is excited at 450 nm. After the detector was set to 522 nm, the excitation radiation wavelength was scanned from about 300 nm to about 560 nm and the emission at 522 nm was recorded. Also, the detector is set to each measurement (Sr 0 3 Ba 0 7. .) 2 SiO 4: Eu 2 + F, (Sr 0 4 Ba 0 6..) 2 SiO 4: Eu 2 + F and ( Sr 0 . 7 Ba 0 . 3 ) 2 SiO 4 :Eu 2 + F phosphor 525 nm, 532 nm and 540 nm light intensity, and for each sample the excitation radiation wavelength from about 300 nm Scan to about 560 nm.

The data in this example shows that the three green phosphors emitted at 522 nm, 525 nm, and 532 nm are more responsive to excitation radiation when the excitation radiation wavelength is less than about 420 nm. Between about 420 and 460 nm, the 522 and 525 nm green phosphor curves fall below both the 532 nm green phosphor and the 540 yellow phosphor. None of the four phosphors are responsive to excitation radiation having a wavelength greater than about 500 to 520 nm.

In short, it will show that unexpected results can be obtained for excitation in a two-phase system relative to a single-phase system.

Elements other than Ba can be used to replace Sr in the citrate matrix; these alternative elements include Ca and Mg. The replacement of barium or strontium with calcium in a sulphate phosphor system based on Sr-Ba has generally been shown to reduce the emission intensity of the single phase (M1) 2 SiO 4 system when the calcium substitution level is less than 40% and will emit Move to a longer wavelength. (See U.S. Patent Application Serial No. 11/269,953). The substitution of large amounts of magnesium for strontium or barium in Sr-Ba-based phthalate phosphors generally reduces the emission intensity and shifts the emission to shorter wavelengths. However, a small amount of magnesium instead of ruthenium or osmium (eg, less than 10%) enhances the emission intensity and shifts the emission to longer wavelengths.

The effect of a small amount of Mg added to the (M1) 2 SiO 4 green phosphate-based phosphor is also shown in U.S. Patent Application Serial No. 11/269,953. The measured phosphor (Sr 0 . 0 5 7 Ba 0 . 4 Mg 0 . 0 2 5 ) 2 SiO 4 :Eu 2 + F and (Sr 0 . 0 5 7 Ba 0 . 4 Mg 0 . 0 2 5 ) The emission spectrum of 2 SiO 4 :Eu 2 + F at 450 nm excitation and compared with the emission of substantially Mg-free phosphor. The Mg-free "control" by the formula (Sr 0 6 Ba 0 4. .) 2 SiO 4 phosphor: Eu 2 + F representative. The purpose of selecting this series of compositions is to show the following effects: Mg first replaces Sr, so that the Ba content is substantially unchanged, and then Mg replaces Ba, so that the Sr content is substantially unchanged.

Adding Mg increases the emission intensity. All three phosphors were observed a peak emission intensity at approximately 540 nm, has the three lowest emission intensity of the phosphorescence phosphor i.e. control (Sr 0 6 Ba 0 4. .) 2 SiO 4: Eu 2 + F. The phosphor of Mg instead of Ba exhibits an emission intensity that is about 6 to 7% higher than that of the control phosphor, and the phosphor of Mg instead of Sr exhibits an emission intensity that is about 10% higher than that of the control phosphor. It can also be observed that the inclusion of Mg shifts the wavelength at which the peak emission occurs to a longer wavelength (ie, slightly closer to yellow and away from green), and this effect is more pronounced when Mg replaces Ba instead of Mg instead of Sr.

It must be reiterated that these results were observed in the single phase, ie (M1) 2 SiO 4 system.

A similar optical observation can be made for the single phase (M2) 3 SiO 5 system and compared with the single phase (M1) 2 SiO 4 observation. U.S. Patent Application Serial No. 11/258,679, filed on Oct. 25, 2005, which is incorporated herein by reference in its entirety in The emission spectra of a single phase of Sr 3 SiO 5 , (Ba 0 . 1 Sr 0 . 9 ) 3 SiO 5 and (Ba 0 . 0 7 5 Mg 0 . 0 2 5 Sr 0 . 9 ) 3 SiO 5 . Phosphorescent phosphor exhibiting maximum emission intensity (Ba 0 . 1 Sr 0 . 9 ) 3 SiO 5 and (Sr 0 . 9 7 Eu 0 . 0 3 ) 3 SiO 5 :F. The phosphors show that not only the highest intensity emission of the five phosphors depicted but also some of the longest peak emission wavelengths (between about 585 and 600 nm) in the graph are completely in the electromagnetic spectrum. Within the orange area. In the exemplary phosphor of the present invention, the phosphorescent system exhibiting the shortest wavelength emission (Ba 0 . 0 7 5 Mg 0 . 0 2 5 Sr 0 . 9 Eu 0 . 0 3 ) 3 SiO 5 :F, the peak wavelength emission is slightly Less than 580 nm.

A series of changes having the formula (Sr 0. 9 7 Eu 0 . 0 3) y SiO examples of phosphors described in Example 5 Sr (or Ba, Ca, etc.) the ratio of the Si content is also shown in U.S. Patent Application No. 11 /258,679. The data shown indicates that the maximum emission intensity occurs when the ratio of Sr to Si is about 3.1, with the second largest intensity appearing at a ratio of about 2.8. The points on the graph indicate that it is not necessary to strictly follow the stoichiometry of (M2) 3 SiO 5 in a single-phase system (again, the amount of M2 series Sr, Ba, Ca, Eu, etc.), among which alkaline earth metals or other elements M The ratio to 矽 is fixed at a value of about 3.0. It is actually advantageous to vary this ratio relative to the usual value for the purpose of enhancing the emission intensity.

Altering the (M2) 3 SiO 5 orange phosphor in the U.S. Patent Application Serial No. 11/258,679, the alkaline earth metal properties (meaning identity) and the content have an effect on both the emission intensity peak and the emission wavelength. In his patent application, the (M x Sr 1 - x ) 2 . 9 1 Eu 0 . 0 9 SiO 5 series of alkaline earth metal M is selected from the group consisting of magnesium (Mg), strontium (Sr), calcium (Ca) and strontium. (Ba) The group consisting of.

U.S. Patent Application No. 11 / 258,679 also have the effect of two different tables Minna alkaline earth metals of Mg and Ca, which shows a series of formulas.. - 2 9 1 Eu 0 0 9 SiO 5 of (Ca x Sr 1 x) The emission spectrum data of the phosphors having x values equal to 0.0, 0.5, and 1.0. The results of correcting x = 1 and x = 0.5 are also shown such that all three peaks have data at substantially the same height as the peak of the composition of x = 0. In the series, compositions having an intermediate ratio of Ca to Sr (in other words, the amounts of Ca and Sr in the composition are substantially the same) show the longest peak emission wavelength at about 605 to 610 nm. This situation is closer to red than the other two members of the series and away from yellow. The predominantly calcium containing composition (x = 1) shows the shortest peak emission wavelength at about 510 nm, which is a color near the green end of the yellow. All compositions containing barium and no calcium were in the middle of the distribution with a peak emission wavelength at about 590 nm.

Referring again to U.S. Patent Application Serial No. 11/258,679, it is found that the substitution of magnesium in the composition (Mg x Sr 1 - x ) 2 , 9 1 Eu 0 . 0 9 SiO 5 reduces the emission intensity and shifts the peak emission wavelength to Shorter wavelengths. The same is true for the case where the phosphor is excited at 403 nm and at 450 nm. For both excitation wavelengths, the composition containing ruthenium as the alkaline earth metal component (x = 0) was emitted at the longest wavelength, and the emission also occurred at about 590 nm. A small amount of magnesium instead of strontium (x = 0.2) can significantly reduce the emission intensity, but does not substantially change the emission wavelength.

More magnesium substitutions to the initial level x = 0.30, and then further reduction to the level of x = 0.35 will increase the emission intensity, although not fully restored to the intensity shown by the magnesium content of zero. At this point in the series of magnesium substitutions (at the level of x = 3.5), the second highest emission intensity in the series was observed. From this concentration, further replacement of strontium by magnesium (to x = 0.4 and x = 0.5, respectively) results in a decrease in strength, initially only to a small extent, and then quite significant. The peak emission wavelengths of the compositions (x = 0.3, 0.35 and 0.4, x = 0.5) are between about 530 and 560 nm.

Effect of Eu activator content in single-phase systems

It is reported that the optimum activator concentration in the composition Me 3 SiO 5 is relative to the alkaline earth metal Me (where Me is Ca, Sr and Ba; see G. Blasse et al. in Philips Research Reports, Vol. 23, Volume 1, The article in 1968) is a few atomic percentages, and similar results are reported in this paper. The effect of changing the content of the ruthenium activator in a single phase bismuthate-based composition (represented by the formula (Sr 1 - x Eu x ) 3 SiO 5 ) has been reported in U.S. Patent Application Serial No. 11/258,679. Compositions having an Eu concentration of about 0.02 have been found to have the highest emission intensity, while the secondary emission intensity composition is x = 0.03.

The two phases of the present invention are generally represented by the formula [Sr x (M1) 1 - x ] 2 SiO 4 ● (1-a) [Sr y (M2) 1 - y ] u SiO 5 : Eu 2 + D based composition, each phase europium activator level is not specified, but usually can be between about 0.01 to about 0.1, wherein Eu 2 + Alternatively the two-phase composition of M1 and M2.

The role of dopant anion D

The effect of incorporating the dopant anion D into the biphasic composition of the present invention is now discussed, wherein D is in the formula [Sr x (M1) 1 - x ] z SiO 4 ● (1-a) [Sr y (M2) 1 - y ] u SiO 5 : The amount of Eu 2 + D is not specifically specified. In this embodiment, at least one of the phases of the composition contains a dopant D selected from the group consisting of F, Cl, Br, S, and N, wherein at least some of the dopant atoms are located in the bismuth citrate The oxygen atom of the crystal is at the lattice point.

U.S. Patent Application No. 11 / 258,679 is given fluorine (F) acting in the one instance a single-phase system, its display phosphor (Sr 0. 9 7 Eu 0 . 0 3) 3 SiO 5 F 6 z emission intensity A graph as a function of fluorine (F) concentration. Z is between 0 and about 0.1. Here, it is shown that the F concentration of between about 0.03 and 0.06 in the (M2) 3 SiO 5 type single phase citrate-based system substantially enhances the emission intensity.

Two-phase embodiment of the invention, can be a halogen such as fluorine dopant in the form of NH 4 F was added to any one phase or two phases. The present inventors have found that when the amount of NH 4 F dopant is extremely small (about 1%), the position of the peak emission is at a shorter wavelength, and when more NH 4 F is added, the wavelength increases as the doping amount increases. The phosphor doped with Eu is capable of emitting light due to the presence of Eu 2 + in the compound, and Eu 2 + undergoes an electronic transition from 4f 6 5d 1 to 4f 7 . The position of the emission band wavelength depends mainly on the material or crystal structure of the substrate, varying between the UV and red regions of the spectrum. This dependence can be explained by the splitting of the 5d energy level of the crystal field. As the crystal field strength increases, the emission band moves to longer wavelengths. The crystal parameter representing the electron-electron repulsion (in other words, the distance between the Eu 2 + cation and the surrounding anion, and the average distance from the distant cation and anion) has the greatest influence on the luminescence peak energy of the 5d-4f transition.

When a small amount of NH 4 F is present, the fluoride anion dopant acts primarily as a flux during the sintering process. Generally, the flux improves the sintering process in one of two ways: the first uses a liquid phase sintering mechanism to promote crystal growth, and the second absorbs and collects impurities from the grains and increases the phase purity of the sintered material. In an embodiment of the invention, the primary phosphorescent system (Sr 1 - x Ba x ) 3 SiO 5 . Both Sr and Ba are extremely cations. There may be smaller cations such as Mg and Ca which may be considered to be impurities. Therefore, further purification of the host lattice results in a more perfect symmetrical lattice and a greater distance between the cation and the anion, thereby weakening the crystal field strength. This is why a small amount of NH 4 F doping will shift the emission peak to a shorter wavelength. The increase in emission intensity with a small amount of F doping is advantageous in producing crystals with fewer defects and higher quality.

When the amount of NH 4 F is further increased, some F-anions will replace the O 2 - anions and be incorporated into the crystal lattice. Cationic vacancies are created to maintain charge neutrality. Since the vacancy of the cation position reduces the average distance between the cation and the anion, the crystal field strength increases. Therefore, as the NH 4 F content increases, the peak of the emission curve shifts to a longer wavelength due to an increase in the number of cation vacancies. The emission wavelength is directly related to the energy gap between the ground state and the excited state, and the energy gap is determined only by the crystal field strength. As a result of the increase in emission wavelength with fluorine and chlorine, it is strongly demonstrated that fluorine or chlorine is likely to be substituted for the oxygen site to be incorporated into the host lattice. On the other hand, as expected, the addition of phosphate ions does not substantially change the emission wavelength. This again demonstrates that phosphate acts as a cation, does not replace oxygen, and thus does not readily incorporate a crystal lattice to alter the crystal field strength of the matrix material. This is especially the case for crystal fields that surround the Eu 2 + ions, which consist essentially of oxygen sites. An increase in the emission intensity obtained by the addition of NH 4 H 2 PO 4 indicates that it acts on the flux as described above.

Optical properties of two-phase citrate-based systems

The optical properties of an exemplary two-phase citrate-based phosphor system are shown in Figures 3-6. Figure 3 is an excitation spectrum of a two-phase system shown in comparison with a single-phase phosphor, and Figure 4 is an emission spectrum of the same two compounds. Figure 5A is an emission spectrum of a two-phase system at three different excitation wavelengths, and Table 1 is a graph of CIE coordinates and Ra of the two-phase phosphor system of Figure 5A. Figure 6 shows the temperature stability defined as the emission intensity as a function of temperature. The figures will be discussed in turn.

Figure 3 is an excitation spectrum of an exemplary two phase bismuth silicate phosphor, which is typically of the formula a(Sr x M1 1-x ) z SiO 4 ●(1-a)(Sr y M2 1-y u SiO 5 :Eu 2+ D represents a specific phosphorescent system 0.72 [(Sr 1.025 Ba 0.925 Mg 0.05 )Eu 0.06 Si 1.03 O 4 F 0.12 ]●0.28 (Sr 3 Eu 0.6 Si 1.02 O 5 F 0.13 ). The comparison is shown for the comparative system single phase phosphor (Sr 1.025 Ba 0.925 Mg 0.05 ) Eu 0.06 Si 1.03 O 4 F 0.12 .

Unexpectedly in Figure 3 is a particular way in which the emission intensity of a two phase system remains constant over a very long excitation wavelength range. The biphasic compound exhibits an emission intensity that varies by no more than about 10% over an excitation wavelength range greater than about 140 nm. In certain embodiments, the excitation wavelength varies by no more than about 5% over a range of excitation wavelengths of 140 nm. In this case, the 140 nm excitation wavelength range is from about 380 to about 520 nm.

For comparison purposes, a single-phase system typically represented by (M1) 2 SiO 4 and in particular the compound (Sr 1.025 Ba 0.925 Mg 0.05 )Eu 0.06 Si 1.03 O 4 F 0.12 is here at the same 360 to 520 wavelength The range shows that the luminescence is reduced by almost 100%.

One advantage of having such a horizontal curve is that the two-phase phosphor system can be excited by a variety of excitation sources and still emit a constant amount of light. This allows the optical engineer to have a particularly high degree of freedom in selecting the radiation source and designing the entire system when using the two-phase bismuthate-based compound of the present invention.

Of course, in other embodiments, constant emission over such a wide range of excitation wavelengths may not be required; in other words, it is only necessary to provide a narrower range of about 80 nm (about, for example, from 380 to 460 nm). Constant emission. Figure 3 shows a compound of the present invention having a bismuth hydride as a two-phase compound 0.72 [(Sr 1 . 0 2 5 Ba 0 . 9 2 5 Mg 0 . 0 5 )Eu 0 . 0 6 Si 1 . 0 3 O 4 F 0 . 1 2 ]●0.28(Sr 3 Eu 0 . 6 Si 1 . 0 2 O 5 F 0 . 1 3 ) still exhibits less than about 10 (or even 5)% variation in this 80 nm excitation range, but Sr 1 . 0 2 5 Ba 0 . 9 2 5 Mg 0 . 0 5 )Eu 0 . 0 6 Si 1 . 0 3 O 4 F 0 . 1 2 The single-phase phosphor shows a decrease of about 50%.

A comparison of the emission spectra of a single-phase bismuthate-based compound with a two-phase citrate-based system is shown in FIG. Illustrative (M1) 2 SiO 4 phosphorescent system again (Sr 1 . 0 2 5 Ba 0 . 9 2 5 Mg 0 . 0 5 )Eu 0 . 0 6 Si 1 . 0 3 O 4 F 0 . 1 2 , and examples (M1) 2 SiO 4 ●M(2) 3 SiO 5 two-phase system is 0.72 [(Sr 1 . 0 2 5 Ba 0 . 9 2 5 Mg 0 . 0 5 )Eu 0 . 0 6 Si 1 . 0 3 O 4 F 0 . 1 2 ] ● 0.28 (Sr 3 Eu 0 . 6 Si 1 . 0 2 O 5 F 0 . 1 3 ). Both the single-phase phosphor and the two-phase system have an excitation wavelength of about 440 nm, and the data has been corrected to more easily compare the width of the curve. Figure 4 shows that the two phase system has a wider emission range than the single phase system.

Figure 5A shows in a different manner that the two phase system is substantially unaffected by the excitation wavelength. Here, the (M1) 2 SiO 4 ●M(2) 3 SiO 5 two-phase system 0.72 [(Sr 1 . 0 2 5 Ba 0 . 9 2 5 Mg 0 . 0 5 )Eu 0.06 Si 1.03 O 4 F 0.12 ]●0.28 (Sr 3 Eu 0.6 Si 1.02 O 5 F 0.13 ) was excited by three different radiation sources with peak excitation wavelengths of 447 nm, 452.5 nm, and 460 nm. Figure 5 shows that the excitation curves between 500 and 660 nm are substantially the same, and the peak emission intensity and the wavelength at which the peak emission occurs (about 575 nm) are substantially the same.

Table 1 gives a quantitative evaluation of the emission curve. Here, the CIE x and y coordinates in the curve excited by the 447.0 nm blue light wafer were 0.311 and 0.304, respectively, and the Ra value was 65.6. The CIE x and y coordinates in the curve excited by the 452.5 nm blue wafer were 0.310 and 0.308, respectively, and the Ra value was 68.5. The CIE x and y coordinates in the curve excited by the 460.0 nm blue wafer were 0.308 and 0.304, respectively, and the Ra value was 70.9.

Temperature stability

Yet another unexpected and advantageous feature of the two phase system of the present invention is its significant temperature stability over a wide temperature range. Figure 6 is a graph showing the emission intensity of a two-phase citrate-based phosphor composition represented by the general formula (M1) 2 SiO 4 ●M(2) 3 SiO 5 , which is emitted at 20 ° C to A curve is measured in the temperature range between 180 ° C and plotted against the intensity indicated by the composition or phosphor at room temperature (about 20 ° C) for the emission intensity at any particular temperature. Shown for comparison is a similar measurement and analysis of single phase phosphor (M1) 2 SiO 4 . The exemplary single phase phosphorescent system (Sr 1.025 Ba 0.925 Mg 0.05 )Eu 0 . 06 Si 1.03 O 4 F 0.12 , and the exemplary two-phase system is 0.72 [(Sr 1.025 Ba 0.925 Mg 0.05 )Eu 0.06 Si 1.03 O 4 F 0.12 ]●0.28 (Sr 3 Eu 0.6 Si 1.02 O 5 F 0.13 ).

The results show that for the two phase system of the present invention, the composition can be configured to illuminate at a temperature above about 100 ° C, with a light intensity of about 90% of the intensity of the emitted light at or above 20 °C. At temperatures greater than about 120 ° C, the intensity of the emitted light is equal to or greater than about 90% of the intensity of the light emitted at 20 °C. Similarly, at a temperature greater than about 140 ° C, the intensity of the emitted light is equal to or greater than about 80% of the intensity of the emitted light at 20 ° C; at temperatures above about 160 ° C, the intensity of the emitted light is equal to or greater than 20 ° C. The intensity of the emitted light is about 80%; and the intensity of the emitted light at a temperature greater than about 180 ° C is equal to or greater than about 70% of the intensity of the emitted light at 20 ° C.

This system is compared with a single-phase system. In a single-phase system, the emitted light intensity is about 80% of the intensity of light emitted at 20 ° C at temperatures of 100 ° C, 120 ° C, 140 ° C, 160 ° C, and 180 ° C, respectively. , 65%, 55%, 45% and 30%.

Clearly, the two phase system provides higher temperature stability than single phase systems. The importance of thermal stability of phosphors (and their lighting systems) is important to the market: general lighting and automotive applications typically require operating temperatures above about 100 °C. In addition, as the input current to the device increases, the junction temperature of the surface of the LED wafer increases. Higher brightness can be achieved by increasing the drive current, but the thermal management of the LED package must be carefully considered. The junction temperature of LEDs with power above 1 W is specified to be about 120 ° C, and it is believed that future applications will require operating temperatures at device junctions of up to about 200 ° C.

White light illumination

White light illumination that can be produced using the two-phase yellow phosphor of the present invention will be discussed below. This section first sets forth an exemplary blue LED that can be used to excite the two-phase yellow phosphor of the present invention. The excitation spectrum of Figure 3 shows that the yellow phosphor of the present invention is capable of absorbing and stimulating light of a wide range of wavelengths, including the blue portion of visible light. According to the general scheme of Figure 1, light from the yellow phosphor of the present invention can be combined with light from a blue LED to produce white illumination. Alternatively, light from the yellow phosphor of the present invention (excited by light from a non-visible UV excitation source) can be combined with other phosphors (eg, blue, green, orange, or red phosphors). Therefore, the color rendering of white light can be adjusted by incorporating other phosphors into the system.

It is important to note that variations in the output wavelength of the blue light wafer (radiation source) used to provide excitation to the phosphor result in current white LED production that does not accurately control the CIE output of the final product. Currently, excitation sources in the form of blue-emitting semiconductor wafers are classified in the range of about 445 nm to 470 nm in 2.5 nm increments. Essentially, the emission intensity of all existing yellow phosphors varies when the wavelength of the radiation source changes, even if the change is only about 2.5 nm. When the YAG material is excited by a radiation wavelength of about 460 nm, the material has an emission maximum, and when the excitation wavelength changes to either side of the 460 nm value, the emission efficiency decreases. As shown in FIG. 3, when the excitation wavelength is increased from 450 nm, the single-phase phosphor emission efficiency mainly based on citrate is drastically lowered.

The CIE value of white LED light produced by a system comprising a blue wafer radiation source and a yellow phosphor depends on the emission ratio of the blue wafer to the yellow phosphor. Even if the power supplied to the radiation source (blue semiconductor wafer) and the amount of yellow phosphor contained in the device are tightly controlled, the final CIE value will change when the wavelength of the light emitted by the blue wafer changes. The data shown in Figures 4 and 5A shows that the CIE value of a white LED using the two-phase yellow phosphor of the present invention is not affected when the wafer wavelength is varied from 447 nm to 460 nm. This advantage is extremely advantageous for enhanced control of CIE values in the production of white LEDs using the two-phase yellow phosphor and blue semiconductor excitation source of the present invention.

Blue LED radiation source

In some embodiments, the light emitted by the blue-emitting LED has a dominant emission peak in a wavelength range between greater than or equal to about 400 nanometers and less than or equal to about 520 nanometers. This light is used for two purposes: 1) it provides excitation radiation to the phosphor system; and 2) it provides blue light that produces white illumination when combined with the light emitted by the phosphor system. Light.

In certain embodiments, the blue LED emits light greater than or equal to about 420 nanometers and less than or equal to about 500 nanometers. In yet another embodiment, the blue LED emits light greater than or equal to about 430 and less than or equal to about 480 nanometers. The blue LED wavelength can be about 450 nm.

The blue light emitting device of the embodiment of the present invention is generally referred to as a "blue LED", but those skilled in the art should understand that the blue light emitting device can be at least one of the following (which covers several jobs at the same time): a blue light emitting diode The body, the body, a surface emitting laser diode, a resonant cavity light emitting diode, an inorganic electroluminescent device and an organic electroluminescent device. If the blue light-emitting device is an inorganic device, it may be a semiconductor selected from the group consisting of a compound semiconductor mainly composed of gallium nitride, a zinc selenide semiconductor, and a zinc oxide semiconductor.

Figure 3 is an excitation spectrum of the yellow phosphor of the present invention, which shows that the novel phosphors are capable of absorbing radiation between about 220 and 560 nm, and most importantly when the excitation wavelength is from about 400 nm to about 530 nm. It has a constant emission intensity at 565 nm when the meter changes.

Example of the use of the two-phase yellow phosphor of the present invention

In an embodiment of the invention, the white light illumination device can use a GaN-based blue LED having an emission peak wavelength between about 430 nm and 480 nm and having an emission peak in the range of about 550 to 580 nm. A combination of wavelengths of the yellow phosphor of the present invention is constructed. Those skilled in the art will appreciate that light emitted from the yellow phosphor of the present invention can be combined with light from a source of visible blue radiation or light that is especially blue, green or red phosphor.

Figure 2 shows an example of white light that can be obtained by combining the yellow phosphor of the present invention with the blue LED described in the above application. This white light is composed of a yellow phosphor having the formula a[Sr x (M1) 1 - x ] z SiO 4 ●(1-a)[Sr y (M2)1 - y ] u SiO 5 :Eu 2 + D A combination of blue LEDs having an emission wavelength of about 450 nm is produced.

Two-phase phosphor processing method

The two-phase phosphor composition of the present invention is synthesized in accordance with a combination of a liquid phase-based sol-gel method and a coprecipitation method. According to such methods, a liquid-based solution of vermiculite and/or a hydrolyzed decane oxide in solution and a hydroxylated/carboxylated alkaline earth metal salt solution are combined to form a suitable for subsequent calcination and sintering. Phosphor precursor. These methods are particularly advantageous for incorporating a halogen dopant into the phosphor lattice.

The phosphor powder is usually synthesized by a so-called dry method called "baking" (a reaction carried out in a solid state). The term "baked" is used because solid state reactions typically require high temperature treatment (e.g., up to about 1400 ° C) for metal atom precursor compounds that are mixed or blended in a desired atomic ratio. The starting materials in the baking process are typically the carbonates, nitrates, oxides or hydroxides of the elements (metal or metalloids) present in the final composition. The molar amount is weighed according to the desired stoichiometric relationship in the final product, and then mixed by any of the following methods, including: 1) pulping, wet ball milling, dry ball milling or milling. The feedstock is then decomposed to produce the final product, which is varied depending on the nature of the material and the desired reaction.

In the baking process, the precursors generally remain solid throughout the reaction, although eventually they will become crystalline products. Since the metal components are particularly difficult to flow in the solid phase, the baking process subjects the precursor compound to a high temperature to facilitate proper diffusion of the atoms, becomes well mixed and finds its regular atomic position in the resulting crystalline structure.

A "flux" can be incorporated into the reaction mixture prior to firing, which is typically a halide salt which is incorporated to promote crystallization and diffusion of the reactants during solid state reaction. While not wishing to be bound by any particular theory, the inventors of the present invention believe that when a flux compound is used in a solid reaction process to promote diffusion and crystallization, the halogen from the flux compound is ultimately predominantly located in the grain boundary region of the material. Not in the crystal lattice of the crystal itself. Therefore, the halogen from the flux compound does not easily affect the optical properties of the phosphor, and the inventors of the present invention have proved to be advantageous.

The liquid-based process includes a sol-gel process and the co-precipitation technique provides the advantage of intimately mixing the components at the atomic level in the liquid phase and where the impurity dopant atoms can be placed on the lattice lattice in a substitutable manner. Embodiments of the present invention combine aspects of the sol-gel process and co-precipitation process, utilizing the capabilities of each of these techniques to mix the reactants of the phosphor batch at the atomic and/or molecular level. In one embodiment of the invention, the alkaline earth metal may be co-precipitated with ruthenium; that is, the alkaline earth metal may be functionalized to form a hydroxylation/carboxylation reaction monomer, such that the compound is capable of reacting with at least a portion of the hydrolyzed decane oxide monomer. This embodiment of the invention may be referred to as copolymerization between the ruthenium-based metal component of the phosphor and the alkaline earth metal component. Since the halogen dopant also participates as a reactant in the liquid phase, it also uniformly diffuses into the reaction mixture and replaces oxygen in the anion lattice at the crystal.

It is known in the art to synthesize a phosphor using a sol-gel process. The term "sol-gel" refers to a reaction mechanism by which a sol of a colloidal solid particle agglomerate suspended in a liquid can be converted into a gel containing a unit containing a liquid phase residue. a substance of a continuous solid framework. The raw material for forming a gel by the sol-gel method may include an oxide of an element such as ruthenium, such as a compound Si(OCH 3 ) 4 (referred to as tetramethoxy decane (TMOS)), and Si (OC 2 H 5 ). 4 (referred to as tetraethoxy decane (TEOS)). A method of forming a sol-gel matrix is to polymerize a polyfunctional monomer in a solution into a relatively large highly branched material by a series of hydrolysis and/or condensation reactions. After the molecule has been at least partially hydrolyzed, the two stanol groups are then reacted (bonded together) in a condensation reaction to form an oligomer containing a siloxane chain (Si-O-Si). The condensation reaction releases water molecules or alcohol molecules. Since the monomer may have four reaction sites, the reaction occurring at the chain side branch may result in cross-linking to promote the formation of a denser and more rigid solid network within the nascent gel. Continued polymerization and/or gelation, which corresponds to an increase in the number of Si-O-Si decane bonds in the gel, results in a greater weight of solid material via continuous crosslinking.

Several steps can be carried out prior to calcination and sintering after gelation and the steps include aging and drying. Aging is defined as the continuation of the crosslinking reaction between the oligomer and the low molecular weight polymer and the general reinforcement of the polymer network. The gels can be dried by a variety of techniques, including boiling to remove most of the liquid, where important parameters are evaporation rate and atmospheric conditions. The three reaction (i.e. hydrolysis, water condensation and alcohol condensation) rate is affected by many factors, including pH, time and temperature, reactant concentration, catalyst (if present), and the nature and concentration of H 2 O / Si molar ratio. The microstructure of the sol-gel derived mesh properties can be altered by controlling these factors.

Precipitation of several different metal-containing compounds from their respective metal alkoxide precursor solutions is commonly referred to as coprecipitation. A coprecipitation method for synthesizing a crystalline inorganic solid comprises dissolving a metal salt in an aqueous solution and simultaneously precipitating all of the metals such that no metal can be separated into a conglomerate of its own kind. The coprecipitated metal is uniformly precipitated to form a ceramic metal oxide precursor. The transition is mixed with the alkaline earth metal in solution as a complex of its hydroxide, carboxylate (including oxalate), nitrate and citrate, wherein the organic ligand is used to prevent a type of metal from Each of the other types of metals separate and separate separately. After precipitating the mixed metal precursor solid, the organic (nitrate, oxalate and hydroxylate) ligands are typically removed by combustion at elevated temperatures, typically above about 200 °C.

According to an embodiment of the present invention, the present invention encompasses that since each of the cerium-containing material and the alkaline earth-containing metal substance can always be hydroxylated and/or carboxylated in one form at a time, each of the two types of substances includes a reactive functional group. The polyfunctional monomer form, and thus a metal such as ruthenium and a true metal such as an alkaline earth metal, can be copolymerized to form a gel network in which a bismuth-oxygen-alkaline earth metal bond can be formed. One of the advantages of the embodiments of the present invention is to maintain the homogeneity between the cerium-containing compound and the alkaline earth-containing compound of the phosphor precursor established in the liquid phase.

At least two phases of embodiments of the invention may be produced in a variety of ways. For example, the starting metals of the desired molar ratio may be mixed with the metal of the class to provide the desired two phases (eg, (M1) 2 SiO 4 and (M 2 ) 3 SiO 5 green and/or An orange phosphor) mixture in which the two phases of the different phosphors are prepared simultaneously in the state of liquid sol-gel/coprecipitation. Alternatively, the two-phase (M1) 2 SiO 4 and (M2) 3 SiO 5 may be separately prepared in the mixture, separately calcined, pulverized, and sintered together. Alternatively, the two phases (M1) 2 SiO 4 and (M 2 ) 3 SiO 5 may be separately precipitated, calcined and sintered and then mixed.

The method of preparing the yellow phosphor of the present invention includes a sol-gel method, a solid reaction method, a coprecipitation method, and a mixing method. An exemplary coprecipitation method comprises: a) dissolving Sr(NO 3 ) 3 , (M1)(NO 3 ) 2 and (M2)(NO 3 ) 2 in water; b) dissolving Eu 2 O 3 in nitric acid ; c) dissolving SrF 2 in nitric acid; d) mixing the solution produced by steps a), b) and c); e) adding (CH 3 O) 4 Si to the solution produced in step d), And then adding an acid to the mixture to initiate precipitation; f) adjusting the pH of the mixture of step e) to about 9; g) drying the reaction product of step f), and then calcining the reaction product Decomposing the precipitate; and h) sintering the precipitate of step g) under a reducing atmosphere.

Many modifications to the illustrative embodiments of the invention disclosed above are readily apparent to those skilled in the art. Accordingly, the invention is to be construed as being limited by the appended claims.

10‧‧‧White lighting system

11‧‧‧radiation source

12‧‧‧Light

13‧‧‧ Phosphor

14‧‧‧Light

15‧‧‧Light

16‧‧‧White lighting

21‧‧‧radiation source

22‧‧‧Substantial invisible light

23‧‧‧Substantial invisible light

24‧‧‧ Phosphor

25‧‧‧ Phosphor

28‧‧‧Color output

1A is a schematic representation of a conventional design of a white light illumination system that includes a source of radiation that illuminates in the visible range and a two-phase bismuth-based luminescence that is responsive to excitation from the source. a phosphor, wherein the light generated from the system is a mixture of light from the phosphor and light from the source; FIG. 1B is a schematic representation of a white light illumination system that includes a non-visible light emission The radiation source is such that the light from the radiation source does not substantially affect the white light generated by the system, and also includes a two-phase bismuth silicate-based phosphor; FIG. 2A is an exemplary two-phase bismuth sulphate. X-ray diffraction pattern of a phosphor having the formula a[Sr x (M1) 1 - x ] z SiO 4 ●(1-a)[Sr y (M2) 1 - y ] u SiO 5 :Eu 2 + D The pattern is provided to illustrate the crystalline nature of the citrate host lattice; FIG. 2B is an exemplary two-phase phosphor a[Sr x (sr x (sr x (s) formed by two different ways (separately sintered, mechanically mixed and simultaneously precipitated) M1) 1 - x ] z SiO 4 ●(1-a)[Sr y (M2) 1 - y ] u SiO 5 :Eu 2 + D An x-ray diffraction pattern indicating that each synthesis method produces a two-phase system; FIG. 3 shows an exemplary two-phase system represented by the general formula (M1) 2 SiO 4 ●M(2) 3 SiO 5 and a single Phase system (M1) 2 SiO 4 phase comparison excitation spectrum showing that the two phase system can be configured to emit no more than 10% change in excitation wavelength range greater than about 340 nm, in some embodiments No more than 5%; Figure 4 is a graph showing the emission spectrum of the excited blue light wafer, and the yellow phosphor a (Sr x M1 1-x ) z SiO 4 (1-a) (Sr y M2 1- y ) u SiO 5 :Eu 2+ D The emission spectrum of the normalized luminescence is compared with the prior art as a white LED package (SrBaMg) 2 SiO 4 ; the yellow light emission of the two-phase yellow phosphor of the invention is shown in the electromagnetic spectrum a wider emission in the green light region; Figure 5A is a yellow phosphor a of the present invention encapsulated in three different white LEDs having three different blue wafer excitation wavelengths (445 nm, 447.5 nm, and 450 nm) ( Sr x M1 1-x) z SiO 4 ● (1-a) (Sr y M2 1-y) u SiO 5: Eu graph showing the emission spectrum of the three 2+ D, the display Degree and CIE are not substantially affected by the excitation wavelength; and Figure 6 is a graph showing the temperature stability of an exemplary two-phase citrate-based system, which is shown between 20 ° C and 180 ° C The emission intensity at the temperature is plotted against the emission intensity at room temperature (20 ° C), and the data from the single phase phosphor shown is used for comparison.

Claims (24)

  1. A phosphor composition having at least two phases mainly composed of citrate, the composition comprising: a first phase having substantially the same crystal structure as (M1) 2 SiO 4 ; and a having a relationship with (M2) a second phase of SiO 5 having substantially the same crystal structure; wherein: M1 and M2 are each selected from the group consisting of Sr, Ba, Mg, Ca, and Zn; at least one phase of the composition contains greater than or equal to 0.0001% by weight of Mg At least one phase of the composition is activated with divalent europium (Eu 2+ ); and at least one of the phases of the composition contains a blend selected from the group consisting of F, Cl, Br, S, and N The dopant D, wherein at least some of the dopant atoms are located on the oxygen atom lattice of the bismuth silicate main crystal.
  2. A phosphor composition having at least two phases mainly composed of citrate, the composition comprising: a first phase having substantially the same crystal structure as (M1) 2 SiO 4 ; and a having a relationship with (M2) a second phase of SiO 5 having substantially the same crystal structure; wherein: M1 and M2 are each selected from the group consisting of Sr, Ba, Mg, Ca, and Zn; and the composition is structured to emit light having an emission intensity of greater than about 80 The variation in the excitation wavelength range of nanometers does not exceed about 10%.
  3. A phosphor composition having at least two phases mainly composed of citrate, the composition comprising: a first phase having substantially the same crystal structure as (M1) 2 SiO 4 ; and a having a relationship with (M2) a second phase of SiO 5 having substantially the same crystal structure; wherein: M1 and M2 are each selected from the group consisting of Sr, Ba, Mg, Ca, and Zn; and the composition is structured to emit light having an emission intensity greater than or equal to The excitation wavelength range of about 80 nm does not vary by more than about 5%.
  4. A phosphor composition having at least two phases mainly composed of citrate, the composition comprising: a first phase having substantially the same crystal structure as (M1) 2 SiO 4 ; and a having a relationship with (M2) a second phase of SiO 5 having substantially the same crystal structure; wherein: M1 and M2 are each selected from the group consisting of Sr, Ba, Mg, Ca, and Zn; and the composition is structured to emit light having an emission intensity greater than or equal to The excitation wavelength range of 140 nm does not vary by more than about 10%.
  5. A phosphor composition having at least two phases mainly composed of citrate, the composition comprising: a first phase having substantially the same crystal structure as (M1) 2 SiO 4 ; and a having a relationship with (M2) a second phase of SiO 5 having substantially the same crystal structure; wherein: M1 and M2 are each selected from the group consisting of Sr, Ba, Mg, Ca, and Zn; and the composition is structured to emit light having an emission intensity greater than or equal to The excitation wavelength range of 140 nm does not vary by more than about 5%.
  6. The composition of claim 4, wherein the excitation wavelength range is from about 380 nm to about 520 nm.
  7. The composition of claim 5, wherein the excitation wavelength range is from about 380 奈 Rice to about 520 nm.
  8. A phosphor composition having at least two phases mainly composed of citrate, the composition comprising: a first phase having substantially the same crystal structure as (M1) 2 SiO 4 ; and a having a relationship with (M2) a second phase of SiO 5 having substantially the same crystal structure; wherein: M1 and M2 are each selected from the group consisting of Sr, Ba, Mg, Ca, and Zn; and the composition is configured to emit light at a temperature greater than 100 ° C, Its intensity is equal to or greater than 90% of the intensity of the light emitted at 20 °C.
  9. The composition of claim 8, wherein the composition is configured to emit light at a temperature greater than 120 ° C, the intensity of which is equal to or greater than 90% of the intensity of the emitted light at 20 ° C.
  10. The composition of claim 8, wherein the composition is configured to emit light at a temperature greater than 140 ° C, the intensity of which is equal to or greater than 80% of the intensity of the light emitted at 20 ° C.
  11. The composition of claim 8, wherein the composition is configured to emit light at a temperature greater than 160 ° C, the intensity of which is equal to or greater than 80% of the intensity of the light emitted at 20 ° C.
  12. The composition of claim 8, wherein the composition is configured to emit light at a temperature greater than 180 ° C, the intensity of which is equal to or greater than 70% of the intensity of the light emitted at 20 ° C.
  13. A two-phase yellow phosphor having a peak emission intensity between about 555 nm and about 580 nm when excited by a radiation source having a wavelength between 220 nm and 530 nm, wherein the phosphorescence The body contains at least one first phase having a crystal structure substantially identical to (M1) 2 SiO 4 and a second phase having a crystal structure substantially identical to (M2) 3 SiO 5 , wherein each of M1 and M2 is selected from the group consisting of Sr, A group consisting of Ba, Mg, Ca, and Zn.
  14. A two-phase yellow phosphor having a peak emission intensity between about 555 nm and about 580 nm when excited by a radiation source having a wavelength between 220 nm and 530 nm, wherein the phosphorescence The body has the following formula a[Sr x (M1) 1-x ] z SiO 4 ●(1-a)[Sr y (M2) 1-y ] u SiO 5 :Eu 2+ D; at least one of M1 and M2 a divalent metal of a group consisting of Ba, Mg, Ca, and Zn; a 0.85; 0.3 x 0.6; 0.85 y 1;1.5 z 2.5;2.6 u 3.3; each of Eu and D is between 0.001 and 0.5; D is at least one anion selected from the group consisting of F, Cl, Br, S and N; and at least some of the D anions are substituted in the phosphor silicate crystal lattice Oxygen.
  15. The phosphor of claim 14, wherein the M1 is selected from the group consisting of Ba and Mg and the M2 is Ba.
  16. The phosphor of claim 14, wherein M1 is Ba and M2 is selected from the group consisting of Ba and Mg.
  17. A white light LED comprising: a radiation source configured to emit radiation having a wavelength of greater than about 280 nanometers, and configured to absorb at least a portion of the radiation from the radiation source and emit a peak intensity between about 555 nm to about a two-phase yellow phosphor of light at a wavelength between 580 nm, wherein the phosphor has the following formula a[Sr x (M1) 1-x ] z SiO 4 ● (1-a) [Sr y (M2) 1 - y ] u SiO 5 :Eu 2+ D; M1 and M2 are at least one divalent metal selected from the group consisting of Ba, Mg, Ca and Zn; a 0.85; 0.3 x 0.6; 0.85 y 1;1.5 z 2.5;2.6 u 3.3; each of Eu and D is between 0.001 and 0.5; D is at least one anion selected from the group consisting of F, Cl, Br, S and N; and at least some of the D anions are substituted in the phosphor silicate crystal lattice Oxygen.
  18. The white light LED of claim 17, further comprising a green phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light having a peak intensity at a wavelength greater than about 510 nanometers.
  19. The white light LED of claim 17, further comprising a blue phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light having a peak intensity at a wavelength between about 420 and about 480 nanometers.
  20. A yellow light illumination system comprising: a radiation source configured to emit radiation having a wavelength of greater than about 280 nanometers, and configured to absorb at least a portion of the radiation from the radiation source and to emit a peak intensity at about 555 奈a two-phase yellow phosphor of light at a wavelength between about 580 nm, wherein the phosphor has the following formula a[Sr x (M1) 1-x ] Z SiO 4 ● (1-a) [Sr y ( M2) 1-y ] u SiO 5 :Eu 2+ D; M1 and M2 are at least one divalent metal selected from the group consisting of Ba, Mg, Ca and Zn; a 0.85; 0.3 x 0.6; 0.85 y 1;1.5 z 2.5;2.6 u 3.3; each of Eu and D is between 0.001 and 0.5; D is at least one anion selected from the group consisting of F, Cl, Br, S and N; and at least some of the D anions are substituted in the phosphor silicate crystal lattice Oxygen.
  21. A color display panel comprising: a radiation source configured to emit radiation having a wavelength of greater than about 280 nanometers, and configured to absorb at least a portion of the radiation from the radiation source and to emit a peak intensity at about 555 nm a two-phase yellow phosphor of light at a wavelength between about 580 nm, wherein the phosphor has the following formula a[Sr x (M1) 1-x ] z SiO 4 ● (1-a) [Sr y (M2 1-y ] u SiO 5 :Eu 2+ D; M1 and M2 are at least one divalent metal selected from the group consisting of Ba, Mg, Ca and Zn; a 0.85; 0.3 x 0.6; 0.85 y 1;1.5 z 2.5;2.6 u 3.3; each of Eu and D is between 0.001 and 0.5; D is at least one anion selected from the group consisting of F, Cl, Br, S and N; and at least some of the D anions are substituted in the phosphor silicate crystal lattice Oxygen.
  22. One preparation of two-phase bismuth sulphate-based has the formula a[Sr x (M1) 1-x ] Z SiO 4 ●(1-a)[Sr y (M2) 1-y ] u SiO 5 :Eu 2+ a method of yellow phosphor of D; wherein M1 and M2 are at least one divalent metal selected from the group consisting of Ba, Mg, Ca, and Zn; a 0.85; 0.3 x 0.6; 0.85 y 1;1.5 z 2.5;2.6 u 3.3; each of Eu and D is between 0.001 and 0.5; D is at least one anion selected from the group consisting of F, Cl, Br, S and N; and at least some of the D anions are substituted in the phosphor silicate crystal lattice Oxygen; the method is selected from the group consisting of a sol-gel method, a solid reaction method, a coprecipitation, and a mixing method.
  23. The method of claim 22, wherein the method is a coprecipitation method.
  24. The method of claim 23, wherein the method comprises: a) dissolving Sr(NO 3 ) 3 , (M1)(NO 3 ) 2 and (M2)(NO 3 ) 2 in water; b) placing Eu 2 O 3 Dissolved in nitric acid; c) dissolving SrF 2 in nitric acid; d) mixing the solution produced by steps a), b) and c); e) adding (CH 3 O) 4 Si to step d) a solution, and then adding an acid to the mixture to initiate precipitation; f) adjusting the pH of the mixture of step e) to about 9; g) drying the reaction product of step f), and then calcining the reaction product The reaction product is used to decompose the precipitate; and h) the precipitate of step g) is sintered under a reducing atmosphere.
TW95138585A 2004-08-04 2006-10-19 Two-phase silicate-based yellow phosphor TWI383034B (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US11/258,679 US7655156B2 (en) 2005-08-03 2005-10-25 Silicate-based orange phosphors
US11/269,953 US7575697B2 (en) 2004-08-04 2005-11-08 Silicate-based green phosphors
US11/417,690 US7601276B2 (en) 2004-08-04 2006-05-03 Two-phase silicate-based yellow phosphor

Publications (2)

Publication Number Publication Date
TW200728434A TW200728434A (en) 2007-08-01
TWI383034B true TWI383034B (en) 2013-01-21

Family

ID=50023222

Family Applications (1)

Application Number Title Priority Date Filing Date
TW95138585A TWI383034B (en) 2004-08-04 2006-10-19 Two-phase silicate-based yellow phosphor

Country Status (1)

Country Link
TW (1) TWI383034B (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001143869A (en) * 1998-12-25 2001-05-25 Konica Corp Electroluminescent material, electroluminescent element and color transformation filter
TW595012B (en) * 2001-09-03 2004-06-21 Matsushita Electric Ind Co Ltd Semiconductor light-emitting device, light-emitting apparatus and manufacturing method of semiconductor light-emitting device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001143869A (en) * 1998-12-25 2001-05-25 Konica Corp Electroluminescent material, electroluminescent element and color transformation filter
TW595012B (en) * 2001-09-03 2004-06-21 Matsushita Electric Ind Co Ltd Semiconductor light-emitting device, light-emitting apparatus and manufacturing method of semiconductor light-emitting device

Also Published As

Publication number Publication date
TW200728434A (en) 2007-08-01

Similar Documents

Publication Publication Date Title
Li et al. Recent progress in luminescence tuning of Ce 3+ and Eu 2+-activated phosphors for pc-WLEDs
Shang et al. Blue emitting Ca8La2 (PO4) 6O2: Ce3+/Eu2+ phosphors with high color purity and brightness for white LED: soft-chemical synthesis, luminescence, and energy transfer properties
KR101109988B1 (en) Fluorescent substance, method for producing the same, and light-emitting device using the same
KR101324004B1 (en) Phosphor and use thereof
KR101497104B1 (en) Metal silicate halide phosphors and led lighting devices using the same
JP5229878B2 (en) Luminescent device using phosphor
TWI443177B (en) Metal silicate halide phosphors and led lighting devices using the same
US9428690B2 (en) Yellow-green to yellow-emitting phosphors based on terbium-containing aluminates
US7445730B2 (en) Phosphor and manufacturing method of the same, and light emitting device using the phosphor
JP5367218B2 (en) Method for manufacturing phosphor and method for manufacturing light emitting device
JP5549001B2 (en) Phosphor and production method thereof
JP5702513B2 (en) Illumination system including radiation source and fluorescent material
JP4457110B2 (en) Highly efficient lighting system based on LEDs with improved color rendering
KR100927154B1 (en) Silicate-based orange phosphors
JP2006008721A (en) Phosphor and luminous equipment using phosphor
JP2010031201A (en) Fluorescent substance and light emission device using the same
KR20130098322A (en) Silicon nitride powder for siliconitride phosphor, caalsin3 phosphor using same, sr2si5n8 phosphor using same, (sr, ca)alsin3 phosphor using same, la3si6n11 phosphor using same, and methods for producing the phosphors
US8529791B2 (en) Green-emitting, garnet-based phosphors in general and backlighting applications
KR101168177B1 (en) Phospher, process for producing the same and luminescence apparatus
JP4805829B2 (en) White light emitting LED with defined color temperature
JP2015526532A (en) Novel phosphors such as novel narrow-band red-emitting phosphors for solid state lighting
EP2236580A2 (en) Nitride and oxy-nitride cerium based phosphor materials for solid-state lighting applications
US20080081011A1 (en) Oxynitride Phosphor and Light-Emitting Device
CN100340631C (en) Phosphor and manufacturing method thereof, and led light source using said phosphor
JPWO2006106883A1 (en) Phosphor, phosphor sheet and method for producing the same, and light emitting device using the phosphor