Qhov sib txawv ntawm miniaturization hauv lub ntiaj teb hluav taws xob yog txuas ntxiv mus thiab tau txhawb nqa los ntawm ntau yam xws li cov neeg siv khoom xav tau kev txav mus los nrog rau kev txhim kho kev ua haujlwm thiab txo cov nqi. Ob peb xyoos dhau los, LED (Light Emitting Diode) thev naus laus zis tshwj xeeb, tau pom kev loj hlob zoo, feem ntau yog vim muaj kev hloov pauv hauv kev lag luam teeb pom kev zoo thiab kev lag luam illumination. Qhov kev txaus siab ntau ntxiv hauv LEDs kuj tau txuas ntxiv mus rau ntau yam kev lag luam nrog rau kev ua tub rog, kev kho mob thiab tshuab pom. Txawm hais tias LEDs tsis yog tshiab rau cov kev lag luam no, lawv qhov kev thov rau me me, kev daws teeb meem siab dua thiab cov khoom sib xws tseem loj tuaj. Qhov tseem ceeb muaj peb yam tseem ceeb ntawm cov khoom hauv LED ib puag ncig. Cov no yog Hla-Qhov, Nto Mount thiab COB (Chip-On-Board). Peb yuav tshuaj xyuas cov no los pab nkag siab txog cov txheej txheem miniaturization hais txog kev tsim thiab siv LEDs rau cov ntawv thov hauv cov khw no. Los ntawm-qhov LEDs tau ua lag luam txij li xyoo 1960s. Lawv tuaj nyob rau hauv ntau yam ntawm lub cev tab sis feem ntau nyob rau hauv qhov loj ntawm 3mm - 10mm inch (Saib daim duab 1).
DUA (1)
Cov khoom siv no tau tuav lub optoelectronics thiab technology sector rau ntau tshaj 20 xyoo. Lawv tseem niaj hnub siv dav hauv ntau daim ntawv thov xws li cov duab digital loj thiab VMS (Variable Message Signs) rau cov qauv ntsuas rau cov neeg siv khoom lossis cov khoom siv hluav taws xob. Txawm hais tias cov LED hom no loj dua qhov loj dua piv rau cov kev tsim kho tshiab, tseem muaj qhov zoo rau kev siv cov khoom siv los ntawm lub qhov xws li kev sib xyaw optics, yooj yim ntawm kev tsim khoom thiab tus nqi qis. Tsis tas li ntawd, ntau cov zaub lossis VMS hom ntawv thov tsis tas yuav muaj cov duab daws teeb meem siab lossis sib xyaw xim kom pom xim tag nrho. Nws tsis yog kom txog rau thaum xyoo 1980 thiab 90s thaum lub xov tooj ntawm tes thiab khoos phis tawj kev lag luam pib lawv qhov nrawm nrawm mus rau hauv tsev ntawm txhua tus neeg siv khoom, uas lub laub rau miniaturization pib. Nto Mount Cheebtsam, txawm hais tias tau tsim nyob rau xyoo 1960, tau hloov pauv sai sai ntawm cov khoom siv hauv qhov pib thaum xyoo 1980s. Cov thev naus laus zis no tsis tsuas yog tso cai rau ntau dua Circuit Court densities, yog li txo qhov loj me, tab sis nws kuj ua kom muaj kev sib dhos ua tau zoo. Tes soldering ua tsawg thiab tsawg tsim nyog. Surface Mount Devices tso cai rau kev txhim kho cov khoom ntawm ob sab ntawm PCB lossis Printed Circuit Board uas tsis yog ib sab xwb. (Saib daim duab 2A – 2B)
Daim duab (2A) - Los ntawm-Qhov Pem Hauv Ntej Sab Populated, Rov Qab Sab - soldering nkaus xwb, tsis muaj Cheebtsam Daim duab (2B) - Nto Mount Cheebtsam rau pem hauv ntej thiab nram qab ntawm PCB Qhov no in-tig muaj lwm yam zoo uas suav nrog txo cov nqi tsim khoom, txhim kho thermal zog , nce kev ntseeg tau thiab ceev tig-ncig lub sij hawm ntawm cov rooj sib txoos. Tsis tas li ntawd, nws muaj peev xwm los tsim cov kev daws teeb meem siab nrog rau cov xim sib txawv ntawm cov lus qhia siv liab, ntsuab thiab xiav LEDs. Blue LEDs kuj tau los ua lag luam nyob rau hauv 1990s coinciding zoo heev nrog kev siv dav ntawm cov khoom siv saum npoo av. Surface mount li niaj hnub no tau dhau los ua cov khoom lag luam ntawm kev xaiv rau feem ntau cov ntawv siv hluav taws xob tsim thiab tuaj hauv ntau hom pob thiab ntau thiab tsawg. Qee qhov ntau tshaj plaws nyob rau hauv lub ntiaj teb LED ntau qhov loj ntawm 0402 uas sib npaug rau .04 "x .02", rau 1210 lossis .12 "x .10" nrog qhov loj me rau cov khoom siv hluav taws xob siab. (Saib daim duab 3)
DUA (3)
Nyob rau xyoo 2000's lig, kev thawb rau kev ua haujlwm ntau dua thiab muaj zog ntxiv rau LEDs tau tshwm sim, ib zaug ntxiv, feem ntau tau tsav los ntawm kev lag luam teeb pom kev zoo thiab kev lag luam illumination. Qhov no ua rau muaj kev qhia dav dav thiab siv COB (Chip-On-Board) thev naus laus zis. COB yog lub tshuab hluav taws xob semiconductor uas "chip" tseem hu ua "tuag" yog txuas ncaj qha rau ntawm lub rooj tsav xwm luam tawm uas siv cov txheej txheem hu ua tuag txuas lossis tuag daim ntawv cog lus. Tus neeg tuag tau muab tso rau ntawm PCB los ntawm kev siv cov khoom siv hluav taws xob los yog cov txheej txheem soldering (Eutectic) thiab tom qab ntawd xaim sib txuas. (Saib daim duab 4) Cov thev naus laus zis no zoo li tshem tawm qhov xav tau ntawm cov ntim khoom ntxiv xws li cov hlau lead thiab cov vaj tsev uas tso cai rau cov thermal dissipative zoo dua, txo qhov loj me thiab nce LED ceev (yog tias xav tau).
DUA (4)
140pcs ntawm LED nti ntim rau hauv thaj tsam tsawg dua 1 square inch Tseem muaj kev sib tw nrog kev siv COB thev naus laus zis tshwj xeeb los ntawm kev tsim khoom. Qee qhov no suav nrog; (A) Cov nqi peev - Cov khoom siv uas yuav tsum tau muaj feem ntau tshwj xeeb thiab kim (B) Kev tsis sib xws thiab kev sib xws yog qhov tseem ceeb hauv ntau daim ntawv thov COB, yog li ntawd, qhov liab qab Die / Chip yuav tsum tau ua tib zoo xaiv thiab sim ua ntej tso rau hauv PCB. Cov txheej txheem no tseem xav tau cov cuab yeej tshwj xeeb heev thiab ntxiv rau, cov txiaj ntsig yuav tsum tau txiav txim siab kom tswj tau tus nqi zoo. (C) Rov ua haujlwm ntawm COB cov rooj sib txoos tuaj yeem nyuaj yog tias twb tau ntim lawm. Qee zaum, tag nrho cov khoom yuav tsum tau muab pov tseg. Yog tias cov khoom tuaj yeem rov ua haujlwm dua, feem ntau, nws tsuas tuaj yeem ua tau ntawm lub hoobkas. Hloov pauv, yog tias lub cuab yeej tsis tau ntim, rov ua haujlwm yog qhov yooj yim rau kev ua piv rau los ntawm qhov thiab SMT thev naus laus zis thiab tus nqi qis dua. (D) Qhov zoo, sib xws thiab hom PCB yog ib qho tseem ceeb los xyuas kom meej qhov zoo ntawm kev sib txuas thiab xaim daim ntawv cog lus ncaj ncees. Ntshiab, hlau-bondable kub feem ntau yuav tsum tau. COB thev naus laus zis tam sim no tau siv los ntawm yuav luag txhua lub tuam txhab LED loj, feem ntau hauv kev lag luam teeb pom kev zoo thiab teeb pom kev zoo. Qhov kev thov nce ntxiv rau cov kev daws teeb meem zoo rau cov teeb pom kev zoo, halogen thiab cov thev naus laus zis zoo sib xws yog tso cai rau kev loj hlob sai hauv COB LED arena. Raws li cov thev naus laus zis no txuas ntxiv txhim kho thiab cov nqi txo qis, COB LED sib dhos ua lag luam xav tias yuav dhau ntawm tag nrho cov qauv LED lag luam hauv ob peb xyoos tom ntej. Txawm hais tias feem ntau cov tuam ntxhab tau tsom mus rau lub zog txuag kev daws teeb meem rau kev teeb pom kev dav dav, muaj ob peb xaiv LED cov tuam txhab uas siv ntau qhov zoo ntawm COB thev naus laus zis hauv ntau lub niche, cov ntawv tshwj xeeb xws li tub rog, kev kho mob, tshuab pom thiab kev ruaj ntseg. Ib qho offshoot ntawm COB thev naus laus zis uas ntxiv dag zog rau kev ua haujlwm thiab muab lub sijhawm ntau dua rau kev ua haujlwm me me yog Direct Attach thiab Flip Chip txoj kev sib dhos. Ob txoj kev tsis tas yuav tsum tau xaim sib txuas yog li tso cai rau qis profile COB sib dhos thaum txhim kho kev ua haujlwm. Tam sim no, ib tug tsawg tus naj npawb ntawm LED manufactures yog muab hom tuag qauv. Tsis tas li ntawd, muaj txawm tias ib tug me me ntawm cov assemblers uas muaj peev xwm ua tau zoo mounting no hom tuag. Ib tus neeg xa khoom loj ntawm DA tuag yog Cree, Inc. Ib qho piv txwv ntawm ib qho ntawm lawv cov DA hom chips yog qhia hauv daim duab 5.
Daim duab (5) DA sab saum toj thiab hauv qab saib
Cov txheej txheem Direct Attach siv cov txheej txheem flux eutectic bonding txheej txheem uas tshem tawm qhov xav tau rau solder paste, preforms lossis conductive adhesives. Qhov tsim nyog flux thiab PCB yog txhua yam uas yuav tsum tau ua kom tau txais txiaj ntsig zoo thaum lub sijhawm rov ua haujlwm. Ib qho piv txwv ntawm kev sib dhos ua nrog tus qauv COB thev naus laus zis piv rau DA kev sib txuas yog qhia hauv cov duab 6A - 6B.
Daim duab (6A) Standard COB los ua ke (Xim Bonding Yuav Tsum Tau)
Daim duab (6B) Direct Attach los ua ke (Tsis Muaj Hlau Bonding Yuav Tsum Tau)
Flip nti thev naus laus zis tig hla lub LED hauv kev taw qhia ntsej muag thiab tso cov electrodes hauv kev sib cuag nrog PCB. Zoo li cov txheej txheem Direct Attach, cov thev naus laus zis no muab cov txiaj ntsig zoo ntawm LED chips uas suav nrog thaj chaw teeb pom kev loj dua, ua kom muaj cua sov zoo dua, nrog rau kev tshem tawm cov kauj ruam ntawm kev sib txuas thiab xaim daim ntawv cog lus shadowing. Txoj kev sib txuas rau flip nti tuag siv qhov hu ua solder "bumps". Cov txheej txheem txuas nrog yog siv cov hom flux uas tsim nyog (raws li hauv DA txoj kev) rau cov pob khaus no thiab tom qab ntawd ua cov txheej txheem rov qab. Vim yog CTE (Coefficient of Thermal Expansion) tsis sib haum ntawm lub flip nti thiab PCB, nws feem ntau tsis pom zoo kom siv cov khoom siv FR-4 tab sis cov ceramic los yog optimized MC (Hlau Core) substrate PCB. Ib tus neeg muag khoom loj ntawm flip nti hom tuag yog Philips LumiLED. (Saib daim duab 7)
Daim duab (7) Flip Chip sab saum toj saib, hauv qab saib thiab sab saib w/ solder pob
Ob qho tib si ntawm cov thev naus laus zis no yog qhov tshiab rau LEDs tab sis tab tom pib ua qhov loj hauv kev teeb pom kev dav dav thiab cov chaw lag luam niche tau hais dhau los. Ntxiv rau qee qhov txiaj ntsig tau piav qhia ua ntej, qhov txo qis hauv thermal kuj mus los ntawm lub qhov taub mus rau COB (saib daim duab 8) yuav ua rau muaj kev txhim kho tseem ceeb hauv lub neej thiab kev ua haujlwm ntawm cov khoom.
Daim duab (8) Thermal Resistance Comparison (Kev sib tshuam rau Pad)
Raws li nrog rau cov cuab yeej tshiab, nws yog ib qho tseem ceeb kom paub tseeb tias koj ua hauj lwm nrog ib lub koom haum uas muaj kev paub txog optoelectronics, paub txog qhov zoo thiab qhov tsis zoo ntawm lub qhov, SMT lossis COB thiab muaj peev xwm muab qhov kev xaiv zoo tshaj plaws rau koj daim ntawv thov. Vincent yog Tus Thawj Saib Xyuas Kev Lag Luam ntawm Marktech Optoelectronics hauv Latham, New York. Nws tau nyob rau hauv optoelectronics teb rau ze li 30 xyoo thiab tau sau los yog co-sau ob peb tsab xov xwm hais txog LED technology. Ntau qhov kev txhim kho tseem ceeb rau LEDs thiab lawv cov ntawv thov tau ncaj qha los ntawm Vincent cov tswv yim thiab kev ua haujlwm ntawm tes.
