CN101323784A - Warm white luminous diode and orange fluorescent powder thereof - Google Patents

Abstract

The invention relates to an orange-yellow fluorescent powder which is a rare earth aluminate with a garnet structure and is characterized in that: the components of the fluorescent powder are added with compounds of elements of IV and V families; stoichiometric equation of the orange-yellow fluorescent powder is: (Sigma Ln)3-xMe<IV>xAl5-ySi<y>O12-(x+y)Nx+y, wherein, Ln is equal to Y, Gd, Ce, Lu and Tb; Me<IV> is equal to Zr and/or Hf; the stoichiometric index of the powder is that: x is more than or equal to 0.001 but less than or equal to 0.1, and y is more than or equal to 0.001 but less than or equal to 0.1. In addition, the invention also discloses a warm white light-emitting diode using the orange-yellow fluorescent powder.

Description

Warm white light light-emitting diode (LED) and orange fluorescent powder thereof

[technical field that the present invention belongs to]

The present invention is relevant with a kind of microtronics and lighting technical field, particularly, this modern technologies field is referred to as " solid state light emitter (Solid state lighting) ", these theories have been brought the progressively innovation of lighting engineering, are that the heterojunction semiconductor light source of matrix has replaced incandescent light and fluorescent light gradually with In-Ga-N (indium-gallium nitride).

[prior art]

New semiconductor lighting technology of rapid rising again on the basis of these two technical fields now, English is referred to as ' Solid statelighting '.In this field, creating with the heterogeneous new type light source of becoming matrix of In-Ga-N and (please refer to S.Nakamura.Blue laser, Springer Verlag, Berlin.1997), the village repaiies one among the research scholar of the original artificial Japan of this In-Ga-N heterojunction that contains a large amount of quantum well.

First is at synthetic in 1994 at the luminous heterojunction that radiating surface contains quantum well.After having spent 5 years ' white light emitting diode ' power of patenting.This photodiode is the heterojunction semiconductor framework (please refer to people's such as S.Schinuzu Taiwan TW156177 patent 01.1.2005) that contains fluorescent material.The gold-tinted combination results white light that the blue light of its heterojunction (that is P-N connects face) emission and fluorescent powder grain send.

As far back as the sixties in 20th century shellfish draw the laboratory to create photodiode, this photodiode adopts GaAs-GaP series of elements in the emission of 800～900nm zone as heterojunction, is referred to as anti-Stokes Y ₂O ₃The fluorescent material of S:ErYb composition is as luminescent material, converts the light of infrared light region to visible light.The photodiode of for many years producing has all adopted this framework, visible emitting on the redness of visible light and green sub-band.If in the first layer of photodiode ' bilayer ' framework (being fluorescent powder grain layer and heterojunction layer), the radiation of fluorescent material is a short-wave radiation, so Soviet Union slip-stick artist B.C. Abramoff (B.C.Ablamov) and B.P. Su Shikefu (B.P.Sushikov) (please refer to the A. gold. ' semi-conductor ', world press, Moscow, nineteen eighty-two) framework that is proposed just directly belongs to the semiconductor framework of GaN series, and this framework is coated with so-called stokes (Stokes) fluorescent material (converting the part primary rays of the different framework of GaN to long-wave radiation).Generally speaking, this two-level architecture characteristics of photodiode are just known by people in the period of 1965～80.

The characteristics of white light emitting diode are that it combines two kinds of radiation: shortwave (blue) and long wave (xanchromatic) radiation.This phenomenon is to use newton's complementary color principle.According to the complementary color principle, use paired complementary color, as blue and yellow, light blue and orange-yellow, blue-greenish colour and redness can obtain white light.These electronics-radiation techniques such as the picture tube of black and white television set and radar have all been used the complementary color principle (please refer to the K. mole have been paused (K.Mordon), B. Zi Waruike (B.Zvoryki), " TV ", world press, nineteen fifty-five for a long time.Leverenz Luminescence of solid, NY, nineteen fifty).The ZnSAg fluorescent material that is distributed in the radar pipe above the window of tube is luminous under the impact of electronics, and the blue-light excited ZnSCdSCu fluorescent material of launching produces photoluminescence.Can observe very bright white light falling into a little of electron beam, this white light is by two independent fluorescent material spectrum compositions.And what use in the picture tube of monochrome television is the phosphor powder layer of layering or individual layer, and this phosphor powder layer is made up of two kinds of cathode-luminescence powder (blueness and xanchromatic), blue light that they are launched and the very bright white light of gold-tinted combination results.

This shows that principle recited above is exactly the long-wave radiation that a kind of shortwave energy transformation of fluorescent material is become another kind of fluorescent material.Two kinds of light (blue light and gold-tinted) are launched the generation white light simultaneously, and this method is early well known.

Occurring a kind of yellow fluorescent powder of special composition and the blue ray radiation of In-Ga-N heterojunction afterwards interacts.The designer once proposed to use yttrium aluminum garnet Y ₃Al ₅O ₁₂: Ce is as this material (please refer to people's such as S.Schinuzu Taiwan TW156177 patent 01.1.2005), and also this just material has caused much not having the company of license to be under an embargo when producing white light emitting diode using this fluorescent material.Yet, this with Y ₃Al ₅O ₁₂: Ce is developed the sixties in 20th century [Blasse G] for the cathode-luminescence powder on basis and (please refer to A Bula end husband .P. Su Shikefu, Soviet Union's works, N635813,12.09.1977 year) and be widely used in the actual production, to make the screen of scintillator, especially CRT.In screen, use blue and xanchromatic cathode-luminescence powder (Y ₂SiO ₅: Ce and (Y, Gd) ₃Al ₅O ₁₂: Ce) mixture is to show chromatic image.

Although this technology is widely used, but still there is a series of shortcoming in it: 1. photodiode is only at high colour temperature T 〉=6500K, chromaticity coordinates is 0.30≤x≤0.31 simultaneously, 0.30 just first the usefulness of photodiode of reproducible white light 2. is very low under the situation of≤y≤0.32, is no more than 10 lumens/watt.

There have been a large amount of patents to be checked and approved at present to revise these deficiencies.They are relevant with the so-called ' warm white ' light source of creation mostly, and colour temperature is 2500≤T≤3500K, and chromaticity coordinates is 0.40≤x≤0.44,0.38≤y≤0.44.

About creating such warm white source, one of them feasible scheme is: at the blue-light excited fluorescent material that produces orange or orange-red light down of In-Ga-N heterojunction.This viewpoint had once proposed such luminescent material in our U.S. US2007/0272899A patent (please refer to N.P.Soshchin etc. U.S. US2007/0272899A application case 29.11.2007) application case, it is by cerium and two orange red radiation of ion-activated generation of praseodymium of yttrium aluminum garnet.

This fluorescent material all has production in a lot of enterprises of country variant, and it can be guaranteed: 1. the colour temperature of white semiconductor light source is T＞3000K, and concrete scope is 3200～3500K; 2. the average light efficiency of photodiode reaches 50～75 lumens/watt.

Certain this fluorescent material also has some substantial shortcomings: 1. λ on the lens cover of photodiode _MaxFluorescent material radiation peak and the λ of=548nm _MaxThe misalignment that exists between the spectrum peak of=610nm causes the technology of ununiformity 2. fluorescent material samples of white light synthetic very complicated and to be difficult to duplicate the quantum output of 3. prepared fluorescent material lower, has only 75～85%; And 4. white lights that can't duplicate T≤3000K, really belong to a fly in the ointment.

[summary of the invention]

For solving the shortcoming of above-mentioned known technology, main purpose of the present invention is the warm white light light-emitting diode (LED) that an orange fluorescent powder is provided and uses this fluorescent material, and it can eliminate above-mentioned shortcoming.

For solving the shortcoming of above-mentioned known technology, another object of the present invention system provides an orange fluorescent powder, and it guarantees can duplicate stable warm white on photodiode.

For solving the shortcoming of above-mentioned known technology, another object of the present invention system provides a new orange fluorescent powder, does not all propose in the former any one piece of patent documentation of the prescription of this fluorescent material.

For achieving the above object, the invention provides a kind of orange fluorescent powder, the rare earth aluminic acid salt that it has the garnet framework is characterized in that: added the compound of IV and V group element in this fluorescent material composition, the stoichiometric equation formula of this orange fluorescent powder is: (∑ Ln) _3-xMe ^IV _xAl _5-ySi _yO _12-(x+y)N _X+y, wherein Ln=Y, Gd, Ce, Lu and Tb, Me ^IV=Zr and/or Hf, this stoichiometry index is: 0.001≤x≤0.1,0.001≤y≤0.1.

For achieving the above object, the invention provides a kind of warm white light light-emitting diode (LED) that uses orange fluorescent powder of the present invention, it has the heterogeneous matrix of becoming of an In-Ga-N, contain a large amount of quantum well, and has a spectrum transmodulator, this photodiode is characterised in that: all luminous flat and the side of this spectrum transmodulator and heterojunction connect, and this spectrum transmodulator is even with concentration, and the form that is centrosymmetric is distributed in this photodiode.

[accompanying drawing summary]

Fig. 1 is a synoptic diagram, and it has illustrated standard analysis fluorescent material (Y _0.75Gd _0.22Ce _0.03) ₃Al ₅O ₁₂Spectroscopic analysis figure.

Fig. 2 is a synoptic diagram, and it has illustrated fluorescent material (No.2 in the table 1) (Gd _0.6Y _0.25Lu _0.05Tb _0.05Ce _0.03) ₃Zr _0.006Al _4.99Si _0.01O _11.984N _0.016Spectroscopic analysis figure.

Fig. 3 is a synoptic diagram, and it has illustrated fluorescent material (No.3 in the table 1) (Gd _0.67Y _0.2Lu _0.05Tb _0.02Ce _0.03) ₃Zr _0.009Al _4.98Si _0.02O _11.971N _0.029Spectroscopic analysis figure.

Fig. 4 is a synoptic diagram, and it has illustrated fluorescent material (No.4 in the table 1) (Gd _0.7Y _0.1Lu _0.04Tb _0.04Ce _0.04) ₃Zr _0.024Al _4.96Si _0.04O _11.936N _0.064Spectroscopic analysis figure.

Fig. 5 is a synoptic diagram, and it has illustrated fluorescent material (No.5 in the table 1) (Gd _0.72Y _0.1Lu _0.01Tb _0.01Ce _0.02) ₃Zr _0.042Al _4.92Si _0.08O _11.878N _0.122Spectroscopic analysis figure.

Fig. 6 is a synoptic diagram, and it has illustrated fluorescent material (No.6 in the table 1) (Gd _0.75Y _0.08Lu _0.05Tb _0.05Ce _0.05) ₃Hf _0.06Al _4.9Si _0.1O _11.894N _0.16Spectroscopic analysis figure.

Fig. 7 a～f is a synoptic diagram, and it shows the synoptic diagram of several particle displaing micro pictures of this fluorescent material sample respectively.

[embodiment]

At first, the shortcoming that the objective of the invention is to eliminate above-mentioned fluorescent material and use the warm white light light-emitting diode (LED) of this fluorescent material.In order to reach this target, orange fluorescent powder of the present invention has the rare earth aluminic acid salt of garnet framework, it is characterized in that: added the compound of IV and V group element in this fluorescent material composition, the stoichiometric equation formula of this orange fluorescent powder is: (∑ Ln) _3-xMe ^IV _xAl _5-ySi _yO _12-(x+y)N _X+y, wherein Ln=Y, Gd, Ce, Lu and Tb, Me ^IV=Zr and/or Hf, this stoichiometry index is: 0.001≤x≤0.1,0.001≤y≤0.1.

Wherein, this fluorescent material is luminous in the orange zone of spectrographic, and light emitting region is from 490～770nm, and the spectrum maximum value is λ _Max〉=570nm, half-wave is wider than 120nm.

The pass of the formed rare earth element positively charged ion of this fluorescent material sublattice is: ∑ Lu=mY+nGd+pCe+qLu+lTb, wherein, f=m+n+p+q+l=3-x.

The concentration of the rare earth element positively charged ion lattice that this fluorescent material is contained is: Y:0.05≤m/f≤0.25; Gd:0.50≤n/f≤0.65; Ce:0.001≤p/f≤0.1; Lu:0.001≤q/f≤0.05; Tb:0.001≤l/f≤0.05.

This silicon ion Si ^{+ 4}Content in the negatively charged ion sublattice is 0.001≤[Si]=y≤0.1 atomic fraction.

This IV family ion content in the positively charged ion sublattice is 0.001≤x≤0.1 atomic fraction.

The particle of this fluorescent material is slightly circle shape, and average particle size is 2.2≤d ₅₀≤ 5 μ m.

The pattern of this fluorescent powder grain is the ball cone, the optical transparency height.

Below explain the physical-chemical essence of fluorescent material of the present invention.Point out that at first the composition of this fluorescent material has the different of essence with principal component; The second, composition proposed by the invention contains 5 kinds of rare earth elements: gadolinium (Gd), and yttrium (Y), cerium (Ce) also has terbium (Tb) and gold-plating (Lu); The 3rd, added IV family metallic element zirconium (Zr) or hafnium (Hf) in the positively charged ion sublattice, the degree of oxidation of these two kinds of compositions all is+4; The 4th, added IV family elemental silicon in the negatively charged ion sublattice, its degree of oxidation is+4; Added V group element in the 5th negatively charged ion sublattice, as nitrogen N, its degree of oxidation is-3.

The principal feature of this composition is: Zr in the positively charged ion sublattice ^{+ 4}And/or Hf ^{+ 4}Ionic replacement main Gd ^{+ 3}, Tb ^{+ 3}, Lu ^{+ 3}Ion (it is to observe the ionic equilibrium rule that the ion in the positively charged ion sublattice is replaced).Gd ^{+ 3}Ionic radius

Coordination valence K=6.Rare earth ion terbium Tb ^{+ 3}Radius

Lu ^{+ 3}For

And replace their IV family metal ion, Zr ^{+ 4}Radius Hf ^{+ 4}Radius be

It also is to observe the equivalent law that the ion that takes place under different ionic valences is replaced.It is different replacing with being replaced the ionic degree of oxidation.Main ion Zr ^{+ 4}And Hf ^{+ 4}-tetravalence attitude.This different valence state forms point defect when taking place to replace.Enter into the Zr of positively charged ion lattice ^{+ 4}The Gd of ionic replacement three valence states ^{+ 3}Ion forms (Zr simultaneously _Gd) °.Be zirconium Zr ^{+ 4}Replace Gd ^{+ 3}, the total surplus electric charge is present in the top of bracket with the form of round dot.

Similarly, the hafnium ion of tetravalence attitude replaces Gd ^{+ 3}Can form (Hf behind the ion _Gd) °.Work as Lu ^{+ 3}And Tb ^{+ 3}Ion is replaced by IV family element ion, and the state of charge of point defect does not change, and the ion that also keeps equivalent is simultaneously replaced.Want lay special stress on a bit, the stoichiometry rule of phosphor compounds composition proposed by the invention is broken at this simultaneously.In the particular case that is proposed is that the ion that is replaced can not disappear or evaporate.The method applied in the present invention is: calculate the necessary quantity of main component in advance, zirconium that is added and/or hafnium composition must meet the ion chemistry metered amounts in the positively charged ion sublattice.

Next be negatively charged ion sublattice how to set up the fluorescent material that proposes.At first, different valence state also can take place in the negatively charged ion sublattice replaces.Anionic node place, ionic radius is Al ^{+ 3}It is 4 silicon ion Si that ion is replaced by the oxidation valence state ^{+ 4}, form new point defect (Si simultaneously _Al) °.And ionic radius is completely different, $\mathrm{\&tau;}$

Thus, formed two some shortcomings in positively charged ion and negatively charged ion sublattice, lattice has two residue positive charges simultaneously.The nitrogen ion N that in the negatively charged ion sublattice, adds proposed by the invention ^-3To reach charge compensation.The nitrogen ion is being replaced oxonium ion O ^-2The time have a remaining negative charge, just (No) '.Like this, charge balance is just set up under this condition below: (Me _Gd) ° _x+ (Si _A1) ° _y=(No) ' _X+y

Form different valence state center (No) ' time need negatively charged ion node (Oo) to do how much expansions because oxonium ion O ^-2Radius

Nitrogen ionic radius

Differ between the two+10%, such gap is possible according to the crystal chemistry standard.

But the ion replacement that is taken place in fluorescent material positively charged ion and the negatively charged ion sublattice can cause being replaced garnet lattice parameter value and become big.According to data of the present invention, for traditional yttrium aluminum garnet Y ₃Al ₅O ₁₂Its lattice parameter is a=1.2001nm, will rise to a=1.2110nm when the part yttrium is changed to this numerical value of gadolinium so.If the part gadolinium is changed to the Tb ion, numerical value will become a so _Tb=1.1942nm.Add a large amount of gold-plating ions in the lattice of this fluorescent material, data become a _Lu=1.1932nm.The present invention draws according to above these data: the more little lattice of the spacing between the ion node is just closely knit more.

IV family element ion replaces the main different valence state that positively charged ion took place and replaces the parameter that can not change lattice, because the amount of ions of being added and few.Similarly, the nitrogen ion N in the adding anion lattice ^-3Replace oxonium ion O ^-2Also can not change the parameter of lattice.

Garnet proposed by the invention (common garnet O ¹⁰ _n-when Ia3d) the fluorescent material lattice parameter reduced, interior lattice parameter was also changing.Simultaneously, for main active ions Ce ^{+ 3}, such lattice variations is no longer along with 5D ₂The degree that ion is excited and decaying, so, Ce ^{+ 3}The ionic radiation spectrum has substantial expansion and moves on to the long zone of spectrum wavelength of visible light.This fluorescent material is by Ce ^{+ 3}Ion excitation, its emmission spectrum wavelength is λ=490～770nm.Below these several figure can more clearly interpret these phenomena.Fig. 1 is standard analysis fluorescent material (Y _0.75Gd _0.22Ce _0.03) ₃Al ₅O ₁₂Spectroscopic analysis figure.As can be seen from the figure, the spectral range of this fluorescent material is λ=505～720nm, spectrum maximum value λ _Max=560.7nm, the wide λ of half-wave _0.5=124.2nm.

Fig. 2 is fluorescent material (No.2 in the table 1)

(Gd _0.6Y _0.25Lu _0.05Tb _0.05Ce _0.03) ₃Zr _0.006Al _4.99Si _0.01O _11.984N _0.016Spectroscopic analysis figure.Its spectral width is λ=498～780nm, and half-wave is wide to be λ _0.5=129.5nm, the spectrum maximum value is λ _Max=571.7nm.

Fig. 3 is fluorescent material (No.3 in the table 1)

(Gd _0.67Y _0.2Lu _0.05Tb _0.02Ce _0.03) ₃Zr _0.009Al _4.98Si _0.02O _11.971N _0.029Spectroscopic analysis figure.The spectral range of this fluorescent material is λ=495～785nm, spectrum maximum value λ _Max=580.4nm, the wide λ of half-wave _0.5=129.2nm, this numerical value are the same with fluorescent material No.2 in practice.

Fig. 4 is fluorescent material (No.4 in the table 1)

(Gd _0.7Y _0.1Lu _0.04Tb _0.04Ce _0.04) ₃Zr _0.024Al _4.96Si _0.04O _11.936N _0.064Spectroscopic analysis figure.Spectral range is from λ=496～789nm.The wide λ of half-wave _0.5=129.9nm, the spectrum maximum value moves to λ _Max=581.5nm.

Fig. 5 is fluorescent material (No.5 in the table 1)

(Gd _0.72Y _0.1Lu _0.01Tb _0.01Ce _0.02) ₃Zr _0.042Al _4.92Si _0.08O _11.878N _0.112Spectroscopic analysis figure.Spectral range is λ=496～796nm.The wide λ of the half-wave of this fluorescent material _0.5=133nm.The spectrum maximum value is λ _Max=582.2nm.

Fig. 6 is fluorescent material (No.6 in the table 1)

(Gd _0.75Y _0.08Lu _0.05Tb _0.05Ce _0.05) ₃Hf _0.06Al _4.9Si _0.1O _11.894N _0.16Spectroscopic analysis figure.Spectral range is λ=498～798nm, and the spectrum maximum value is λ _Max=583.2nm, for the wide smaller situation of its half-wave, the present invention will make explanations to it below.

By we can draw following these conclusions to the analysis of this 6 figure: 1. all non-constant width of the spectrum of these fluorescent material proposed by the invention, wideer 60～90 microns than the fluorescent material of standard; 2. these fluorescent material proposed by the invention all move to Long wavelength region, and the spectrum maximum value has moved 23 microns; 3. the spectrum half-wave of these fluorescent material proposed by the invention is wide to have enlarged 9 microns.

Be accompanied by the variation (partial data is listed in table 1) of the curve of spectrum, the radiation spectrum of these fluorescent material also has some other variation.Become λ=582nm as radiating predominant wavelength from λ=569nm.Variation has all taken place in the Reinheitszahl that typical example is exactly radiating chromaticity coordinates index (seeing also table 1) and color.Be necessary to point out that the spectrum maximum value of these fluorescent material all is positioned at the orange-yellow zone of radiating.

Fluorescent material with these spectrum advantages, the rare earth element ratio in its positively charged ion sublattice is: ∑ Ln=mY+nGd+pCe+qLu+lTb.Wherein, m+n+p+q+l=3-x.

An important characteristic of these fluorescent material proposed by the invention is: remove the element or the IV family element that add in the positively charged ion sublattice, i.e. and Zr and/or Hf, the summation of all rare earth elements equals 3 atomic fractions.And but the ion branch rate variation range of these interpolations is 0.001≤x≤0.1 atomic fractions.

Be necessary to point out the principal element of positively charged ion sublattice, i.e. gadolinium ion Gd ^{+ 3}, ruthenium ion Y ^{+ 3}, gold-plating ion Lu ^{+ 3}, terbium ion Tb ^{+ 3}And cerium ion Ce ^{+ 3}, its concentration can influence the ionic radiation spectrum that proposes and change.The Zr that adds ^{+ 4}And Hf ^{+ 4}Element, its atomic percent can be so that the radiation spectrum deviation of the fluorescent material that proposes be less.

For example, in the positively charged ion sublattice, add a large amount of Zr ^{+ 4}Ion can be with the wide lifting Δ of the half-wave of radiation spectrum=1～1.5nm.If the Zr that adds ^{+ 4}Ionic concn is lower, the wide Δ=2～2.5nm that then reduces of the half-wave of radiation spectrum.And the Hf that adds ^{+ 4}Ionic concn can cause taking place the persistence of fluorescent material substantial variation.In the positively charged ion sublattice, add Hf ^{+ 4}Ion can with time length of twilight sunset from τ _eHow=100 rise to τ second _eHow second=122.The clear luminescence decay time that stops back fluorescent material that excites of this parameter list has reduced 1/e doubly.And to reach this effect and only need add a spot of Hf ^{+ 4}Get final product.Work as Hf ^{+ 4}Ionic concentration is 0.01% o'clock, can promote the persistence of fluorescent material, if but this ionic concentration is reduced to [Hf ^{+ 4}]≤0.001, the time length of twilight sunset then drops to τ _eHow second=98.

Table 1 has been enumerated the lighting engineering parameter of these fluorescent material.Can judge that from chromaticity coordinates, predominant wavelength, glow color purity and colour temperature all these fluorescent material all belong to orange-yellow luminescent material among the present invention.As far as we know, up to the present also there is not one piece of document to deliver this orange fluorescent powder based on garnet.

Table 1.

N o	The basal component of fluorescent material	Add mixture atomic fraction SiO 2MeN	Chromaticity coordinates	Spectrum, wavelength X Max, nm	λ 0.5	CT, (.K)
							1	(Y 0.75Gd 0.22Ce 0.03) 3Al 5O 12	--	0.3725 0.4337	560.7	124.2	4518
2	(Gd 0.6Y 0.25Lu 0.05Tb 0.05Ce 0.03) 3 Zr 0.006Al 4.99Si 0.01O 11.984N 0.016	0.01 0.006	0.4528 0.4280	571.7	129.5	2935
							3	(Gd 0.67Y 0.2Lu 0.05Tb 0.02Ce 0.03) 3Zr 0.009Al 4.98Si 0.02O 11.971N 0.029	0.02 0.009	0.4514 0.4238	580.4	129.2	2924
4	(Gd 0.7Y 0.1Lu 0.04Tb 0.04Ce 0.04) 3 Zr 0.024Al 4.96Si 0.04O 11.936N 0.064	0.04 0.024	0.4569 0.4242	581.5	129.9	2846
							5	(Gd 0.72Y 0.1Lu 0.01Tb 0.01Ce 0.02) 3Zr 0.042Al 4.92Si 0.08O 11.878N 0.122	0.08 0.042	0.4572 0.4180	582.2	131	2795
6	(Gd 0.75Y 0.08Lu 0.05Tb 0.05Ce 0.05) 3Hf 0.06Al 4.9Si 0.1O 11.894N 0.16	0.100.06	0.4516 0.4137	583.2	131	2843

It may be noted that will obtain this orange-yellow fluorescent material must possess following this condition: the concentration of each rare earth element is Y:0.25≤m/m+n+p+q+l≤0.5 in the positively charged ion lattice,

Gd： 0.50≤n/m+n+p+q+l≤0.65

Ce： 0.001≤p/m+n+p+q+l≤0.1

Lu： 0.001≤q/m+n+p+q+l≤0.05

Tb： 0.001≤l/m+n+p+q+l≤0.05。

The present invention is done some important supplementary notes here.At first, we have pointed out that the positively charged ion yttrium in the fluorescent material is no more than 0.5 atomic fraction, gadolinium ion Gd ^{+ 3}Atomic fraction reach 0.65, the maximum concentration of these two elements is than for [Gd]/[Y]=2.6 so.Thus, this fluorescent material can be referred to as gadolinium-yttrogarnet.But also more than these two of the principal elements in this fluorescent material prescription have also added gold-plating ion Lu in its composition ^{+ 3}With terbium ion Tb ^{+ 3}The effect of these two complementary elements just is to control the cubic(al)grating parameter of this garnet phosphor powder.Just as mentioned above, the ion of these interpolations can reduce the parameter value of lattice and promote the tension force of interior lattice.Though yttrium (Y), gold-plating (Lu) and these elements of terbium (Tb) are not equal on atomic mass, and reality their concentration in the composition of this fluorescent material equates, so these atoms of elements branch rates can reach 0.05 unit.In view of the above, the name of fluorescent material proposed by the invention is called GYLTAG (being gadolinium-yttrium-gold-plating-terbium-aluminium garnet).

The Ce that adds ^{+ 3}Number of ions value difference also can be brought significantly and change.If Ce ^{+ 3}Ionic concentration is low, and the spectrum half-wave of radiation curve is wide can to increase Δ=1～3nm, if the amount of this active ion much then can cause the maximum value of radiation spectrum to be dwindled.Contain high density Ce ^{+ 3}The major advantage of ionic fluorescent material is, when fluorescent material is excited by photodiode, when in essence change takes place in exciting power, its again radiation have very high rectilinearity.The optical excitation that takes place on heterojunction is 10 ²¹～10 ²³Quantum/cm ²Second, these blue quantum are fallen on the fluorescent powder grain and are produced fluorescence.The quantum output that this process produces is bordering on 1 (0.95).If but the radiation power of the different framework of semi-conductor were promoted 10 times, the light quantity subnumber that the standard garnet phosphor powder is radiated would increase by 6～7 times.This phenomenon is to break away from straight-line law, is referred to as the non-linear phenomena (according to linear law, along with the power that promotes ten times, quantum number is correspondingly 11-fold increase also) of the luminescent material of saturated phenomenon or white light emitting diode.

We find in research work, with active ion Ce ^{+ 3}Starting point concentration promote 50～75% and just can eliminate the saturated phenomenon that fluorescent material produces because of exciting power fully.The present invention simultaneously will point out, above the optics that mainly is meant fluorescent material narrated excite again, if in the process of strengthening the photodiode electric power, promote the heating power that drops on the fluorescent material, the phenomenon of radiating energy decreases can appear so simultaneously.The reason of this phenomenon is based on the material of fluorescent material thermal expansion to have taken place.And thermal expansion causes weakening of interior crystal field, makes luminous energy descend.We observe, and fluorescent material is heated to 125 ℃, and its luminous efficacy is reduced to original 1/2.We test this fluorescent material on special instrument, observe the influence of the composition of fluorescent material to it.But fluorescent material of the present invention is heated to T=140 ℃, Gd in the lattice ^{+ 3}The fluorescent material that ion content is maximum has been preserved 85～87% luminous efficacy, and the more less fluorescent material of gadolinium ion content has been preserved 89～91% luminous efficacy.

Why this fluorescent material has these advantages, is because the silicon ion Si in its negatively charged ion sublattice ^{+ 4}Content be 0.001≤[Si]=y≤0.1 atomic fraction.

Chemical equivalent equation as this fluorescent material is write, and has added silicon in its composition, exactly, and part A l ^{+ 3}Ion is replaced by its negatively charged ion sublattice fully.We find, add silicon ion Si in the garnet phosphor powder composition ^{+ 4}, can also impel Ce on the yttrium aluminum garnet framework ^{+ 3}The displacement of ionic radiation spectrum generation long wave.Undoubtedly, a little less than the influence of silicon ion is replaced the influence that is brought than the same valency of gadolinium-yttrium.If the latter can so that radiation spectrum to 45～50 microns of red area displacements, Si so ^{+ 4}The displacement that ion brings has 8～10 microns.And such displacement is only at Si ^{+ 4}Just can take place under the not high situation of ionic concn.

Be necessary to point out, in composition, add silicon ion Si ^{+ 4}Can change the framework of fluorescent material excitation spectrum, the maximum absorption scope moves on on λ=460～465nm from λ=450～455nm.The surface of fluorescent powder grain has two kinds of distinct colors, ash-incarnadine.But at this moment the optical absorption value of fluorescent powder grain and optical transparency can not change to some extent.

We understand, silicon ion Si ^{+ 4}Concentration range be 0.001≤Si≤0.1 atomic fraction.When the concentration of silicon ion is got minimum value, i.e. Si ^{+ 4}=0.001 atomic fraction, the main component ratio Gd/Y=2.6 of fluorescent material, the radiation spectrum maximum value is not moved.When the content of silicon ion is Si ^{+ 4}Long wave displacement=1nm obviously takes place in=0.01 atomic fraction.Silicon ion Si ^{+ 4}Optimum content be 0.045～0.065 atomic fraction, in this scope, can make the long wave displacement reach 8～10nm, simultaneously with the wide expansion 1.5～2.5nm of the half-wave of radiation spectrum.The light that fluorescent material sends belongs to the orange-yellow zone of spectral radiance.

This advantage of this fluorescent material can realize under this condition below: add IV family element in the positively charged ion sublattice of fluorescent material, the content of these elements is 0.001≤x≤0.1 atomic fraction in the sublattice.

Undoubtedly, the Zr that is added ^{+ 4}And/or Hf ^{+ 4}The silicon ion Si of fluorescent material negatively charged ion sublattice is advanced in ionic quantity and interpolation ^{+ 4}Content very approaching.Why this also must add Zr just in the positively charged ion sublattice ^{+ 4}And/or Hf ^{+ 4}Physical-chemical reason place.Comparison diagram 1 and other several figure are in the spectrum maximum value of blue region, and these elements is added with the lifting that helps the fluorescent material receptivity as can be seen.Do not add zirconium or hafnium if (please refer to Fig. 1) in the standard samples, " blueness " of its heterojunction initial light reflection can be very high so.And contain the fluorescent material of zirconium or hafnium element, and its blue light reflecting part then reduces by 1.5～1.8 times, and simultaneously, the brightness of this fluorescent material does not only descend, and increases to some extent on the contrary.

Point out among the present invention, the point defect of positive charge takes place can form when different valency is replaced in positively charged ion and negatively charged ion sublattice.Have a lot of different schemes can preserve the crystalline electric neutrality, the method that the present invention selects is to add the nitrogen ion N of negative charge in the negatively charged ion sublattice ^-3, form (No) ' center.Be necessary to point out, this formation thing (No) ' be not very stable, strong reaction can take place in it when fluorescent material high temperature is synthetic.We once proposed to add the method for ZrN or HfN: add ZrN or HfN in the fluorescent material composition, form paired point defect immediately.This fluorescent material is when preparation, and the characteristics of its hot-work treatment process have been added zirconium nitride or hafnium nitride just in fluorescent material.

In the fluorescent material composition, add zirconium nitride or hafnium nitride, oxide raw material is carried out hot-work handle in high temperature and reducing gas.The characteristics of this operation are, add nitride HfN and/or the ZrN or their the equivalent molecule mixture of IV family in raw material, are placed in 1520～1700 ℃ the stove to heat 4～8 hours, and the density of hydrogen in the stove is 2～5% of nitrogen-hydrogen mixed gas.

As mentioned above, negative charge N in the negatively charged ion sublattice ^-3Ionic content is 0.001≤[N]≤0.1.Point defect equilibrium equation in positively charged ion and the negatively charged ion sublattice is: (Me ^IV _Ln) °+(Si _Al) °=2 (No) ', specifically for each element of IV family, its equation is:

(Zr _Ln)°+(Si _Al)°＝2(No)

(Hf _Ln)°+(Si _Al)°＝2(No)

The standard synthesis method of garnet phosphor powder has a lot, according to synthesis method, uses rare earth oxide Gd ₂O ₃, Y ₂O ₃, CeO ₂, Lu ₂O ₃, Tb ₄O ₇, the aluminum oxide of formation negatively charged ion sublattice, even solid-phase catalyst is as the raw material of fluorescent material.Solid-phase catalyst can be accelerated from aluminium oxide Al ₂O ₃With single aluminate LuAlO ₃Form garnet in the mixture.Its response formula is:

3LuAlO ₃+Al ₂O ₃→Lu ₃Al ₅O ₁₂

Usually use barium fluoride BaF ₂And AlF ₃As this catalyzer.

The original reagent of part can be changed, and for example, the available hydrogen oxide compound replaces oxide compound in the sol-gel method, but at this moment its solid state reaction does not change.As mentioned above, should add ZrN and/or HfN in the fluorescent material composition that is proposed, even silicon oxide sio ₂Food ingredient is as follows:

Gadolinium sesquioxide Gd ₂O ₃-0.6M (mole)

Yttrium oxide Y ₂O ₃-0.25M

Oxidation gold-plating Lu ₂O ₃-0.05M

Terbium sesquioxide Tb ₄O ₇-0.025M

Cerium oxide CeO ₂-0.05M

Zirconium nitride ZrN-0.005M

Silicon oxide sio ₂-0.01M

Aluminium oxide Al ₂O ₃-2.49M

Barium fluoride BaF ₂-0.32M

The speed that batching is placed in the three-stage roll mill with 60 rev/mins stirred 1 hour, and the threading capacity is 0.8 liter a firm aluminium crucible then.Crucible is put in the stove of automatic transmission, at weak reducing gas (2% H ₂+ 98% N ₂) heated 6～8 hours down, furnace temperature remains on 1520～1620 ℃.Take out batching, be cooled to room temp, use hot hydrochloric acid soln (1: 1) pickling then, then wash with water again.The surface of fluorescent powder grain forms ZnOSiO ₂Nanometer layer, ZnOSiO ₂Be from ZnSO ₄7H ₂O (1%) and Na ₂SiO ₃(1%) forms in the solution.Fluorescent powder grain is placed in the strainer filters, then T=120 ℃ down air-dry 2 hours Powdered until forming.It is vivid orange-yellow that the synthetic in this way fluorescent powder grain that makes is.

The spectrum of this fluorescent material and colorimetric performance can be measured with the spectral radiance analyser of three look companies (Sensing).The curve of spectrum that draws comprises:

-chromaticity coordinates x, y;

-chromaticity coordinates u, v;

The maximum value position of-the curve of spectrum;

-relative luminous intensity;

The half-wave of-the curve of spectrum is wide;

-radiating purity of color;

-colour temperature (° K);

-colour rendering index Ra;

-radiating predominant wavelength, λ _Max

-color ratio K _R, K _G, K _B

Fig. 1 is standard fluorescence powder (Y _0.75Gd _0.22Ce _0.03) ₃Al ₅O ₁₂Radiation spectrum.The parameter comparison array of all samples is in above-mentioned table 1.By above-mentioned table 1 as can be seen, according to chromaticity coordinates, the radiation major part of this fluorescent material all is positioned on the orange-yellow sub-band, compares with standard samples, and its spectrum maximum value has moved

The half-wave of the curve of spectrum is wide from λ _0.5=124nm is changed to λ _0.5=133nm.In addition, we observe, and compare with standard samples, and the colour temperature of this fluorescent material has changed 1700K, and luminous intensity is L=83～87%.Based on these data, and consider that the spectral radiance of this fluorescent material is positioned on λ=555～583nm, can be sure of that the synthetic orange fluorescent powder has very high photon output.Exceed much as sample No.3 and its photon output valve of No.4 standard samples than η=0.95.

The same with the spectrum of measuring the fluorescent material sample with the colorimetric performance, measure the granularity of fluorescent material with special instrument-laser particle size distribution tests instrument, even can determine the form of fluorescent powder grain with microscope.We find in the course of the work, the rounded shape of fluorescent powder grain.This point is very important, because when filling the fluorescent material conversion layer in heterojunction, the fluorescent powder grain of this form can not damage the surface of heterojunction.Fig. 7 a～f shows the wherein synoptic diagram of several particle displaing micro pictures of this fluorescent material sample respectively.The fluorescent material composition of this Fig. 7 a, b representative is the No.2 in the table 1.These particles are circular, part shape spherical in shape, and each particulate faceted pebble has all surpassed 12.

The fluorescent material that Fig. 7 c, d represent respectively is No.4.These particles are bigger than top two kinds of fluorescent powder grains.On the indivedual faces of particulate, can also see the vestige that pickling stays.All these particulate color and lusters all are yellow.Yellow is the peculiar color and luster of the cerium compound of garnet framework.

What Fig. 7 e, f represented is the solid phase synthesis fluorescent material sample of standard.These particles promptly without any faceted pebble do not have optical transparency yet.

The specific area of fluorescent powder grain is S=32000cm among Fig. 7 a, the b ²/ cm ³, the neutrality line diameter is 2.2≤d ₅₀≤ 5 μ m, mean diameter is 4≤d _Cp≤ 7 μ m.The tight zone that uses the fluorescent powder grain of this fineness to make does not have a large amount of perforation.The concentration of tight zone is the D=200 micron, and according to the weight method, the density of tight zone can reach p=4.0g/cm ³This phosphor material powder has high density like this rounded ball cone of this fluorescent powder grain has been described, and its optical transparency is very high.

Undoubtedly, this surface just as minute surface of fluorescent powder grain helps the lifting of its quantum output.Be necessary to point out that we find that the particle of all standard sampless all has pointy shred faceted pebble, the distortion in a large number of this particulate surface, reflection coefficient is not high.The form that the standard fluorescence powder particles is discussed out is impossible because in these particles in addition the none coating of particles be complete.

Pointed out that below the main function of fluorescent material proposed by the invention is to make warm white light light-emitting diode (LED).But the present invention also will propose other very important application direction.At first be to be used on the red scintillator, it can be used for detecting X ray and the gamma-radiation that sends from various radio isotope and material.Its principle of work is to absorb the x-ray photon primary energy to the transition of K layer.Main Gd ^{+ 3}Ion produces the K-transition when ENERGY E=48.8KeV, the K-transition energy of terbium atom is E=52KeV, and the K-transition value maximum when energy is E=61.1KeV of the Lu atom in the fluorescent material composition.This has illustrated and has been used to detect intermediate energy by the scintillator that contains these compositions that propose (X ray of E=45～80KeV) is optimal.

Simultaneously, the fluorescent material of gadolinium-yttrium-gold-plating-terbium composition is highly suitable for the isotropic substance radiation Xe that detected energy is E=0.081KeV ¹³³, even energy is the isotropic substance Kr of E=0.044KeV ⁷⁹Detector based on this fluorescent material once repeatedly was used to attempt analyzing nuclear-response heap transuranium element (isotropic substance Am, Pr, U etc.), and had obtained good result.Must be pointed out that the yield of radiation of this fluorescent material is the monocrystalline CdWO of standard ₄1.8 times of technology sample are equal to and are used in scintillator best on the counter Laminographic and (come from Gd ₂O ₂SCePr) yield of radiation.

This fluorescent material also has characteristics to be, it is had an effect energetically with heat or ultracold neutron, and nuclear response Gd takes place ¹⁵⁵+ n → Gd ¹⁵⁹+ e+ γ.The thermal neutron that gadolinium absorbed reaches 40000 barns (b), is hundred times of receptivity of other element and isotropic substance Li, B, Gd etc.So fluorescent material is bound to be applied in this field in the near future.

But this fluorescent material that contains gadolinium, its application scale are the most still in the solid state light emitter field.The main framework of photodiode is based on InGaN (In-Ga-N) heterojunction (figure does not show), contains a large amount of quantum well, and heterojunction semiconductor is positioned in sapphire (or silicon carbide of monocrystalline) the heat conductor substrate.

There is spectrum transmodulator (figure does not show) at substrate surface, can be elementary blue-light excited by the heterojunction radiating.This spectrum transmodulator is distributed in the light-emitting area of heterojunction and side and all primary rays light with the uniform form of concentration and has an effect mutually.Photodiode proposed by the invention must possess such framework, because the light that goes out from the side-emitted of heterojunction reaches whole semi-conductive 40%.The duty factor of spectrum transmodulator depends on its thickness to a great extent, can change 60～95% heterojunction primary rays.

When the distribution that is centrosymmetric of spectrum transmodulator, concentration is even, and the thickness on each radiator plane and side is 100～200 microns, and Ga-In-N heterojunction semiconductor so proposed by the invention just has very high rotary light performance.

The important rotary light performance of this photodiode and spectrum transmodulator not only refers to the light transfer capability, also comprises the primary emission light of its porous necessity.When the parameter of warm white is x=0.45, during y=0.43, the transmittance of the spectrum transmodulator of this photodiode reaches 20% of elementary blue ray radiation.

The advantage of this photodiode also shows as its only warm white of launching except glow color has homogeneity, chromaticity coordinates is 0.41≤x≤0.45,0.40＜y≤0.43 simultaneously, and colour temperature is 2800≤T≤3400K.This photodiode meets white light radiating standard, is optimum illuminations in the normal lighting.

In sum, photodiode of the present invention is except glow color has homogeneity, also show as its only warm white of launching, chromaticity coordinates is 0.41≤x≤0.45,0.40＜y≤0.43 simultaneously, colour temperature is 2800≤T≤3400K, in addition, it more can create brighter, the light source that optical throughput is bigger, therefore, really can improve the shortcoming of known warm white light light-emitting diode (LED).

Though the present invention discloses as above with preferred embodiment; yet it is not in order to limiting the present invention, anyly has the knack of this skill person, without departing from the spirit and scope of the present invention; when the change that can do a little and retouching, so protection scope of the present invention is when looking being as the criterion that accompanying Claim defines.

Claims (12)

1. orange fluorescent powder, the rare earth aluminic acid salt that it has the garnet framework is characterized in that: added the compound of IV and V group element in this fluorescent material composition, the stoichiometric equation formula of this orange fluorescent powder is: (∑ Ln) _3-xMe ^IV _xAl _5-ySi _yO _12-(x+y)N _X+y, wherein Ln=Y, Gd, Ce, Lu and Tb, Me ^IV=Zr and/or Hf, this stoichiometry index is: 0.001≤x≤0.1,0.001≤y≤0.1.

2. orange fluorescent powder as claimed in claim 1, it is luminous in the orange zone of spectrographic, and light emitting region is from 490～770nm, and the spectrum maximum value is λ _Max〉=570nm, half-wave is wider than 120nm.

3. orange fluorescent powder as claimed in claim 1, the pass of its formed rare earth element positively charged ion sublattice is: ∑ Lu=mY+nGd+pCe+qLu+lTb, wherein, m+n+p+q+l=3-x.

4. orange fluorescent powder as claimed in claim 3 wherein defines f=m+n+p+q+l, and the concentration of contained rare earth element positively charged ion lattice is: Y:0.05≤m/f≤0.25; Gd:0.50≤n/f≤0.65; Ce:0.001≤p/f≤0.1; Lu:0.001≤q/f≤0.05; Tb:0.001≤l/f≤0.05.

5. orange fluorescent powder as claimed in claim 1, wherein this silicon ion Si ^{+ 4}Content in the negatively charged ion sublattice is 0.001≤[Si]=y≤0.1 atomic fraction.

6. orange fluorescent powder as claimed in claim 1, wherein this IV family ion content in the positively charged ion sublattice is 0.001≤x≤0.1 atomic fraction.

7. orange fluorescent powder as claimed in claim 1, wherein the particle of this fluorescent material is slightly circle shape, and average particle size is 2.2≤d ₅₀≤ 5 μ m.

8. orange fluorescent powder as claimed in claim 1, wherein the pattern of this fluorescent powder grain is the ball cone, the optical transparency height.

9. orange fluorescent powder as claimed in claim 1, it can be produced by in high temperature and weak reducing gas oxide raw material being carried out the hot-work processing, the characteristics of this method are: the nitride HfN and/or ZrN or their the equivalent molecule mixture that add IV family in raw material, be placed in 1520～1700 ℃ the stove and heated 4～8 hours, the density of hydrogen in the stove is the 2-5% of nitrogen-hydrogen mixed gas.

10. warm white light light-emitting diode (LED) that uses orange fluorescent powder as claimed in claim 1, it has the heterogeneous matrix of becoming of an In-Ga-N, contain a large amount of quantum well, and has a spectrum transmodulator, this photodiode is characterised in that: all luminous flat and the side of this spectrum transmodulator and heterojunction connect, this spectrum transmodulator is even with thickness, and the form that is centrosymmetric is distributed in this photodiode.

11. warm white light light-emitting diode (LED) as claimed in claim 10, wherein the thickness of this spectrum transmodulator is 100 to 250 microns.

12. warm white light light-emitting diode (LED) as claimed in claim 10, wherein the light that this photodiode sent has the warm white accent, and chromaticity coordinates is 0.41≤x≤0.43,0.39≤y≤0.420, and colour temperature is 2760≤T≤3500K.

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