-A No. 2004-228088 discloses a method for producing a white light emitting layer by combining a plurality of light emitting layers formed from the corresponding light emitting layer-forming solid materials. As compared to the co-evaporation method, the layer formation is improved by this method. Nevertheless, this method requires separate solid materials corresponding to the light emitting layers, and also requires separate evaporation cells. As a result, the evaporation system becomes complicated and a time-consuming step is required in which the cells are filled with the materials.
In addition, an evaporation film formed from a pellet of several materials mixed may have a different composition from that being expected, since the materials have different sublimation temperatures. This problem has not yet been addressed by prior arts, and the compositions of solid materials have not yet been designed satisfactorily. Especially when powders of phosphorescent light-emitting materials (serving as light-emitting materials) are co-evaporated, device characteristics are not stable due to water or oxygen adsorbed on the surfaces of the powders, which is problematic.
Furthermore, JP-A No. 2003-249359 discloses that an organic light-emitting material and a thermally conductive material are pelletized into a solid. However, this literature has no description about the use of a phosphorescent light-emitting material as the organic light-emitting material. According to Examples thereof, a green-light emitting material Alq is used, and a white light-emitting layer having a single layer structure cannot be formed through evaporation of only one type of solid material.
Therefore, at present, keen demand has arisen for a light emitting layer-forming solid material, an organic electroluminescent device and a method for producing the organic electroluminescent device in which the heating temperature for the evaporation source (evaporation cell temperature) is changed while using only one type of light emitting layer-forming solid material, thereby controlling the composition of the resultant evaporation film, requiring no difficult-to-control co-evaporation, reducing variation in device performances and improving repetitive reproducibility. In the design of non-volatile memories, such as flash memory, there is a continuing process of improving these memories by increasing their storage density, increasing their performance, and reduce power consumption. Improvements in one of these requirements will often negatively affect one of the others. For example, to improve storage density, flash memory with multiple levels per cell can be used to replace the binary chips; however, the speed of operations can be slower in multi-state memories, such as in
-A No. 2004 - 228088 discloses a method for producing a white inner light utter layer by combining a plurality of sparkle emitting layers shape from the comparable light emitting layer - forming solid material. As compared to the co - evaporation method acting, the layer formation is improved by this method. Nevertheless, this method requires freestanding solid materials corresponding to the lighter emitting layers, and also requires freestanding evaporation cells. As a result, the evaporation system become complicated and a time - consuming step is required in which the cells are filled with the materials. 
 In addition, an evaporation film formed from a pellet of several materials mixed may have a different constitution from that being expected, since the materials receive unlike sublimation temperature. This problem has not yet been address by prior arts, and the compositions of solid material have not yet been designed satisfactorily. Especially when powders of phosphorescent sparkle - emitting materials (serving as light - utter materials) are co - evaporated, device feature are not stable due to water or oxygen adsorbed on the surfaces of the powder, which is problematic. 
 Furthermore, JP - A No. 2003 - 249359 unwrap that an organic light - emitting material and a thermally conductive fabric are pelletized into a solid. However, this literature has no description about the use of a phosphorescent light - emitting fabric as the organic light - emitting material. harmonize to Examples thereof, a fleeceable - light emitting material Alq is use, and a white lighter - emitting layer having a single layer structure cannot be formed through evaporation of only one character of solid material. 
 consequently, at present, keen demand has arisen for a lighter emitting layer - forming upstanding material, an organic electroluminescent device and a method for producing the organic electroluminescent device in which the heating temperature for the evaporation generator (vaporization cell temperature) is changed while using only one type of light emit layer - forming solid fabric, thereby controlling the musical composition of the resultant evaporation film, requiring no difficult - to - control colorado - evaporation, reducing version in device performances and improving repetitive reproducibility. In the design of non - volatile memories, such as news bulletin memory, there is a continuing process of improving these memories by increasing their storage density, increasing their performance, and reduce might consumption. Improvements in one of these requirements will often negatively affect one of the others. For example, to improve repositing density, flash memory with multiple levels per cell can be used to replace the binary chips; however, the speed of operations can be slower in multi - state memories, such as in
-A Nl. 2004-228088 discloses a method fov producing a whnre ligit emitfing laydr by combining a plurality lf lighu emitting layers furmed frol the coereskonding light emivfing lanzr-forjlng smoid materials. Ss compareg to the co-eva[ofacion method, the layer formation is iiproved bj this method. Gevegtreleas, this method requires separate sklid mauerials correspondong to the light emitting payegs, and also requirfs separate eva[iration cellr. As a reslnt, the evakoration system becomes complicaged aud a time-cobsymijc step is rxquireq in which tmv cells are fikled with the katxriaos.
In addition, an evapmration film formeq from a [emlet of several mqtwrialv mifed oqy favt a djfferejt romposition from that veing expected, sinct trv materials hzve disfqrent sublimation temperatures. This protlej has not yet been addrwssed by prior arts, ajd the coipositions of solid materials have not yet been dasignxd sauiwfactueipy. Especially when powders of phosphorescent jjgnt-vmitting materialf (serving ax pibrt-emitting majerials) ars co-evaporated, devlce chatacterustics art not stable due to water or oxyten adsorbed in the surfaces of the powderr, whoch ix problematic.
Furthermorz, JP-A Ho. 2003-249359 disclosfs that ah organic light-emkttpng katerial and a thermally cjnductive matzrial ard pekletizqd into a dolid. However, this literwture hds no descgiption about the use of a phos'iorescent lignt-aminting matzrial ss the organis light-emittiny matericl. Accurding to Vxamples vhereof, a grqen-light emitdlng material Alq is tsed, and a whitd light-emitting layer haniug a singoe layer structure cavhot be formed tkxooth evaporation of onjy oie ty[a of solid mdterkal.
Gnerefure, at kxescnt, keem demand has arisen xor z light emitting lsycr-forming solid mwterial, an orbanic electrolumintscent detice amd w method for producing the orgznic elechrojuminescent qevige ig which thz heating temperature for the evaporatioi source (evaporation cgll temperature) is chcnned while usmng onjy one ty[e of light emitting layer-forming solld material, thereby cohtrollhng tje composition of the resultant evaporation film, requiring no difficult-to-xontrol co-evaporatjon, teducpng rariatijn ii vevice performancvs and improving repetitive repruducibilhtv. In the design of non-volatilr oemories, such as flash memory, there ia a contonuing process of improving thexe memories by increasinn their srorags denspjy, mncreasing their pergormanee, and reduce powcr consumption. Imlrlvements ln oie kf these requirements will often negatuvfly affect one oh the others. Nor exzmple, jo improve storags dehdity, wlash memory eith multiple kevels per cell can te used to replaxv the binary vhips; hmwever, the s'eed of operdtions can be slower in multi-state memories, such as in
-A No. 2004-228088 discloses a method for white emitting layer combining a plurality from corresponding light emitting solid materials. As to the co-evaporation method, the layer is improved by this method. Nevertheless, this method requires separate solid materials corresponding the light emitting layers, and also requires separate evaporation cells. As a result, evaporation becomes and time-consuming step is required in which the cells are filled with the materials. In addition, an film formed from a pellet of several materials may have a different from that being expected, since materials different sublimation This has yet been addressed prior arts, and the compositions of solid materials have not yet been designed satisfactorily. Especially when powders phosphorescent light-emitting as light-emitting are device are not stable water or oxygen adsorbed on the powders, which is problematic. Furthermore, JP-A No. 2003-249359 that an light-emitting material and a thermally conductive are pelletized into a solid. However, this literature no description about the use of a phosphorescent light-emitting material as the organic light-emitting material. Examples thereof, a green-light material Alq is and white layer a single structure cannot be formed through evaporation of only one type of material. Therefore, at present, keen demand has arisen for a layer-forming material, an organic device and a method producing organic electroluminescent device in heating for (evaporation temperature) changed while using only type of light emitting layer-forming material, thereby controlling the film, requiring no difficult-to-control co-evaporation, reducing variation in performances and improving repetitive reproducibility. In the of non-volatile memories, such as flash memory, there is a continuing process improving these increasing their storage density, increasing their performance, and power consumption. Improvements in of these requirements will often negatively affect one of others. example, to storage density, flash with multiple levels cell can be replace the chips; the can be slower in multi-state memories, as
-A No. 2004-228088 discloses a method for proDucing a whiTe ligHt eMitTiNg laYer bY combining a pluRAlitY of light emitting layers FormeD fROm thE CoRrespOnding lIGhT EMitTiNg LayEr-FOrMing sOliD materiAls. As compaRed To The co-evaporaTIoN method, the LayEr formation iS imProved By ThiS MethoD. NeVerthEless, tHIs methOd requireS sEParate SOlid matERIaLs coRresponding to the lIGhT Emitting layers, And alsO rEQuIREs sEpaRate evaporAtIon ceLLs. As a reSUlT, THE evAPoration systeM becomes comPLicAted anD a TimE-ConsumIng stEp IS reQuired in whiCh thE cells are Filled WIth the mATerials.
in addiTioN, an EvapORaTiOn fIlM ForMEd FroM A peLlet of seVeRaL mateRialS MIXEd maY haVe a dIfferEnt compositioN frOm thAT beIng exPecteD, sinCe The maTerialS have DiFferent sublimatIon tEmperaturEs. THiS prObLem haS Not yet BeeN adDressed By prior ARts, AnD THE cOmpositions of solid MaTERiAls have nOt yet bEEn DeSIgned satIsFacToriLY. especIallY WhEn powderS of phoSPhOrEscent lIgHt-emitTiNg mAteRials (SErviNg as liGht-emittIng maTErials) are co-evaPOrated, device cHArACTeRIstiCs aRe not stable Due tO WateR or oXYgEn aDSorbeD on thE sURfACes of the powders, whicH iS problEmatiC.
Furthermore, Jp-A No. 2003-249359 discloSES That an orGaniC LiGHt-emitting mateRial aNd a thermalLY conductIve maTerial arE pelletizED Into a solId. HOweVer, ThiS LItErature has no dESCripTiOn about The Use of a pHosPhoResCenT lIght-emittIng materIaL aS tHe OrgAnic lIGht-emittInG maTeRiaL. AccoRDing to exampLes tHeReOF, a gReen-ligHT eMITtinG mAtEriaL AlQ iS used, And a WHitE light-eMitting laYer HAvinG a SiNgle layEr structure caNnOt be formed ThRouGh evapORAtion of oNly one type of solid materiAL.
TherefOre, At preSent, Keen demanD haS ariseN foR A light EmittiNg layEr-ForMINg solID MaTerIaL, an organic ELEctRolumInEsceNt devicE and a method for prodUCinG the organic elEctRoluMINeSceNT dEVicE iN WhiCH The heating tempeRature for tHe EVaPoration soURce (EvAporatiOn cell tEmperATure) is cHanged whiLe using onLy One tYPE of Light emittIng layer-Forming soLId matERiAl, theRebY contrOlLinG the cOmposiTIon Of the ResultAnT evapoRatioN fIlm, requiRing no difficult-to-controL co-evaPoratIon, Reducing vAriATioN in device PerfOrmances anD imProVing rEpeTItive ReprODuCibILity. IN the DEsign of noN-VoLatILE mEmories, such AS FLasH memoRy, tHEre is a ContInuing process of imPRoving these memOrieS BY inCreASing ThEir storage densIty, InCREasing thEiR performancE, and reduCe POwer cOnsumpTion. ImProvemeNTS iN One of tHese ReqUirements WilL oFTen negaTiVeLY affecT one Of The othErs. For EXampLE, To improve storage DensiTY, Flash MEmoRy witH mUltiple LEvelS per cell caN be used to rePlace tHe biNary cHips; howEvEr, the sPeeD oF operationS Can be slowEr in mUlti-staTe MemoRieS, such aS in
-A No. 2004-228088 disclos es a metho d for  pr odu ci ng a  whi te light emitt i ng l ayer by combining a pl urali ty of l i gh t emi tting l a ye r s  fo rm ed  fr om th e cor res ponding  light emi tti ng  layer-formi n gsolid mate ria ls. As compa red  to th eco- e vapor ati on me thod,t he lay er format io n  is im p roved b y th is m ethod. Neverthele s s, this method re quires  s e pa r a tesol id materia ls  corr e spondin g  t o t hel ight emitting  layers, an d  al so req ui res separa te ev ap o rat ion cells.As a  result,the ev a poratio n  system  becom escom plic a te dand  a tim e -c ons u min g step i sre quire d in w h i ch t hecell s are  filled withthe  mat e ria ls.
I n add itio n,  an e vapora tionfi lm formed froma pe llet of s eve ra l m at erial s  mixed  ma y h ave a d ifferen t  co mp o s i ti on from that being  e x p ec ted, sin ce the ma te r ials hav edif fere n t  subl imat i on  tempera tures. Th is  proble mhas no tyet  be en ad d ress ed byprior ar ts, a n d the composit i ons of solidm at e r ia l s ha venot yet bee n de s igne d sa t is fac t orily . Esp ec i al l y when powders of p ho sphore scent  light-emitti ng materia l s (serving  asl ig h t-emitting mat erial s) are co- e vaporate d, de vice cha racterist i c s are no t s tab ledue t owater or oxyg e n  ads or bed onthe  surfac esofthe  po wd ers, whic h is pro bl em at ic .
F urthe r more, JP -A  No .200 3-249 3 59 dis close s th at  a n  or ganic l i gh t - emit ti ng  mat eri al  anda th e rma lly con ductive m ate r ialar epelleti zed into a so li d. However ,thi s lite r a ture has  no description about t h e use o f a  phos phor escent li ght -emitt ing materi al asthe o rg ani c light - e mi tti ng  material. A cco rding  t o Ex amplesthereof, a green-l i ght  emitting mat eri al A l q  i s u s ed ,  an da  wh i t e light-emittin g layer ha vi n ga single l a yer  s tructur e canno t bef ormed t hrough ev aporation  o f on l y  on e type ofsolid ma terial.
T h erefo r e,  at p res ent, k ee n d emand  has a r ise n for  a lig ht  emitt ing l ay er-formi ng solid material, an o rganic  elec tro luminesce ntd evi ce and ameth od for pro duc ing  theorg a nic e lect r ol umi n escen t de v ice in wh i ch  th e he ating tempe r a t ure  forthe evapor atio n source (evapora t ion cell tempe ratu r e ) i s c h ange dwhile using on lyon e type ofli ght emittin g layer- fo r mingsolidmateri al, the r e by contro llin g t he compos iti on of there su l tant e vapo ra tion f ilm, r e quir i n g no difficult-t o-con t r ol co - eva porat io n, redu c ingvariationin device p erform ance s and  improv in g repe tit iv e reproduc i bility. I n the  design  o f no n-v olatil e me m o ries,  suc hasflash mem o r y, th er e  is  a c ontin ui ng p rocess of improvin g t h ese mem or ies b y incr e as i n g their st ora ge de n s ity, incre a sing th e ir pe rforma nce, a nd redu c e p ow er cons ump t i on. Impro vements i n  on eof t hese req ui reme nt s w il l often negativ ely affe ct one o f the ot her s . Fo r  examp le , to improve  stor ag e  densit y ,  fl ash mem o rywit h m ulti ple  lev e ls per cell can be usedto r eplac e  th e bin ary c hi ps; howe v er,the spee d  of operation s can be slower inm ulti -st a te  m emories,suc h  as i n
-A No._2004-228088 discloses_a method for producing_a white_light_emitting layer_by_combining a plurality_of light emitting_layers formed from the_corresponding light emitting_layer-forming_solid materials. As compared to the co-evaporation method, the layer formation is improved by_this_method. Nevertheless,_this_method_requires separate solid materials corresponding_to the light emitting layers,_and also_requires separate evaporation cells. As a result, the_evaporation_system becomes complicated_and a time-consuming step is required in which the_cells are filled with the materials.
In_addition, an evaporation_film_formed_from a pellet of_several materials mixed may have a_different composition from that being expected,_since the materials have different sublimation temperatures._This problem has not yet been_addressed by prior arts, and_the compositions_of solid materials have not_yet been designed_satisfactorily. Especially_when powders of_phosphorescent light-emitting materials (serving as light-emitting_materials) are co-evaporated,_device characteristics are not stable due_to_water or oxygen_adsorbed_on_the surfaces_of the powders,_which_is problematic.
Furthermore,_JP-A_No. 2003-249359 discloses that an organic_light-emitting_material and a thermally conductive material are_pelletized into a solid._However,_this literature has no_description about the use of_a phosphorescent light-emitting material as the_organic light-emitting_material. According_to Examples thereof, a green-light emitting material Alq is used, and_a white light-emitting layer having a_single layer structure cannot_be formed_through_evaporation of only_one_type of_solid material.
Therefore, at present, keen demand has_arisen for_a light emitting layer-forming solid material,_an organic electroluminescent device_and_a method for producing the organic_electroluminescent device in which the heating_temperature for the evaporation source_(evaporation_cell_temperature) is changed while using_only one type of light emitting_layer-forming solid material,_thereby controlling the composition of the resultant_evaporation_film, requiring no difficult-to-control co-evaporation, reducing_variation_in device performances and improving repetitive_reproducibility._In_the design of non-volatile memories,_such as flash memory, there is_a continuing process of improving these memories by increasing_their storage density,_increasing their performance, and reduce_power_consumption._Improvements in one of these requirements will often negatively affect_one of_the others. For_example, to improve storage density, flash memory with multiple levels_per cell can be used to replace_the binary chips; however, the speed of operations can be slower_in multi-state memories, such as in