LED backlights Saib kuj: LED-backlit LCD

LED backlights

Saib kuj: LED-backlit LCD

LCD nrog LED matrix backlight

LED backlighting nyob rau hauv cov ntxaij vab tshaus xim hauv ob hom: dawb LED backlights thiab RGB LED backlights. ^[3] Dawb LEDs siv feem ntau hauv cov ntawv cim tseg thiab duab ntxig, thiab ua txhua yam txawb LCD ntxiab. Ib tug dawb LED yog feem ntau ib qho xiav LED nrog dav spectrum daj phosphor los ua rau lub emission ntawm lub teeb dawb. Txawm li cas los xij, vim tias txoj kev hnyav spectral peaks ntawm daj, nws yog ib qho khoom txom nyem rau cov kis ntawm cov xim liab thiab xim ntsuab ntawm lub LCD. Qhov no ua rau cov liab thiab ntsuab primaries hloov mus rau daj, txo cov xim gamut ntawm cov lus ^[4] . RGB LEDs muaj xws li xim liab, xiav, thiab ntsuab ntsuab thiab tuaj yeem tswj tau kom muaj xim txawv xim dawb. RGB LEDs for backlighting muaj nyob rau hauv siab kawg xim cov ntaub ntawv pov thawj xws li HP DreamColor LP2480zx saib los yog xaiv HP EliteBook phau ntawv xov xwm, thiab ntau tshaj cov neeg siv khoom siv qhia qib siab xws li Dell's Studio series laptops uas muaj kev xaiv RGB LED zaub.

RGB LEDs tuaj yeem xa ib qho xim loj loj rau cov vias ^[5] . Thaum siv peb cais LEDs ( xim ntxiv xim ntsuab ) lub tsom teeb muaj peev xwm tsim tau cov xim spectrum uas sib dhos cov xim lim hauv cov duab LCD pixels . Nyob rau hauv no txoj kev, lub lim passband yuav tsum tau narrowed thiaj li hais tias txhua xim tivthaiv cia tsuas yog ib tug luv luv band ntawm spectrum los ntawm lub LCD. Qhov no pab txoj kev zoo ntawm cov khoom tso vim tias tsawg lub teeb yuav thaiv thaum pom tshwm dawb. Tsis tas li ntawd, qhov tseeb ntawm cov xim liab, ntsuab, thiab xiav ntsiab lus yuav tau txav mus deb kom pom tseeb tias cov khoom muaj peev xwm nthuav tawm ntau xim.

Ib txoj kev tshiab los ntxiv kom cov xim ntawm LED-backlit LCD panels raws li xiav LEDs (xws li GaN) illuminating ib txheej ntawm nanocrystal phosphors, thiaj hu ua Quantum Dots (QD) , ^[6] uas hloov cov xiav wavelengths rau lub siab nyiam wavelengths li nqaim-bandwidth ntsuab thiab liab xim rau qib siab illumination ntawm LCD los ntawm qab. Chaw tsim tshuaj paus, Nanosys , cov neeg pab leg ntaubntawv uas cov xim tawm ntawm cov dots tuaj yeem tig precisely los ntawm kev tswj qhov loj ntawm cov nanocystals. Lwm cov tuam txhab uas ua raws li cov qauv no yog Nanoco Group PLC (UK), QD Vision thiab 3M , ib daim ntawv tso cai ntawm Nanosys. ^[7] Sony tau siv Quantum Dot technology los ntawm US lub tuam txhab QD Zeem Muag ^[8] los nthuav qhia LCD TVs nrog ib qho kev ua haujlwm zoo -ntse LED muag teeb muag nyob rau hauv lub sij hawm Triluminos hauv 2013. Nrog lub xiav LED thiab optimized nanocrystals rau cov xim ntsuab thiab xim liab nyob rau hauv pem hauv ntej ntawm nws, lub resulting ua ke dawb lub tso cai rau rau ib qho sib npaug los yog zoo dua gamut tshaj uas tawm los ntawm ib tug kim kim ntawm peb RGB LEDs. Nyob rau ntawm Consumer Electronics Show 2015, Samsung Electronics , LG Electronics , suav TCL Corporation thiab Sony pom QD-enhanced LED-backlighting ntawm LCD TVs. ^{[9] [10]}

CCFL backlighting kuj tau zoo dua rau qhov no. Muaj ntau cov qauv LCD, ntawm tus nqi pheej yig TN-cov xim thaij S-IPS los sis S-PVA panels, muaj ntau qhov teebmeem CCFLs sawv cev ntau dua 95% ntawm NTSC xim specification.

Muaj ntau ntau yam kev cov nyom nrog LED backlights. Uniformity yog ib qho nyuaj mus cuag, tshwj xeeb tshaj yog cov LEDs hnub nyoog, nrog txhua tus laus laus ntawm ib tus nqi sib txawv. Tsis tas li, kev siv peb qho chaw sib txawv rau xim liab, ntsuab, thiab xiav txhais tau hais tias lub ntsiab lus dawb ntawm cov zaub yuav txav li cov hnub nyoog LEDs ntawm cov nqi sib txawv; Dawb LEDs kuj cuam tshuam los ntawm no phenomenon, nrog kev hloov ntawm ntau pua kelvins raug kaw. Dawb LEDs kuj raug kev txom nyem los ntawm xiav txee ntawm kev kub siab dua los ntawm 3141K txog 3222K rau 10 ° C mus rau 80 ° C ntsig. ^[11] Fais fab kev ua tau zoo kuj yog kev sib tw; thawj tiam kev siv yuav muaj peev xwm siv zog tshaj lawv cov CCFL counterparts, tab sis nws yog ib qho ua tau rau ib qho khoom siv LED kom muaj zog dua. ^{[ Yuav tsum tau ]} Hauv xyoo 2010, tam sim no cov qauv qhia LED tuaj yeem muaj peev xwm ua tau zoo. Piv txwv li, tus non-LED version ntawm 24 " Benq G2420HDconsumer zaub muaj 49W noj piv rau 24W ntawm qhov LED version ntawm tib lub teeb (G2420HDBL).

Tiv thaiv cov lus sib tw nrog RGB thiab dawb LED backlights ib 'advanced remote phosphor' ^[12] LED technology tau tsim los ntawm NDF Special Light Products, tshwj xeeb rau cov ntawv nyeem high-end thiab ntev li cockpit , ^[13] Huab Cua Tswj kev saib xyuas thiab kev mob nkeeg. Cov tshuab no siv xiav cov roj teeb coj los siv nrog cov nplooj ntawv uas muaj cov khoom phosphorous luminescent luam tawm rau xim hloov dua siab tshiab. Lub hauv paus ntsiab lus zoo li Quantum Dots, tab sis cov phosphors hos yog qhov muaj zog ntau dua li cov quantum dot nano-particles rau cov kev siv uas yuav tsum tau siv mus ntev ntev hauv kev xav ua hauj lwm ntau dua. Vim hais tias daim ntawv phosphor yog muab tso rau ntawm ib qho chaw nyob deb (sab nraud) ntawm LED nws muaj kev kub ntxhov ntau dua li phosphors hauv cov LEDs dawb. Yog li ntawd, tus whitepoint tsis tshua nyob ntawm tus kheej LEDs, thiab kev quab yuam ntawm tus kheej LEDs dhau lub neej, ua rau ntau homogenous backlight nrog paub xim sib luag thiab txo qis lumen depreciation.

Kev siv ntawm cov backlights hauv cov lus qhia hauv phau ntawv tau nthuav tawm. Sony tau siv LED backlights hauv qee qhov nws siab tshaj plaws kawg VAIO phau ntawv sau txij thaum xyoo 2005, thiab Fujitsu tau qhia cov phau ntawv sau nrog LED rov qab hauv xyoo 2006. Hauv 2007, Asus , Dell , thiab Kua ua tswvcuab LED rov mus rau hauv qee cov qauv ntawm lawv tus qauv. Raws li 2008, Lenovo tau tshaj tawm LED-backlit notebooks. Lub Kaum Hlis 2008, Apple tau tshaj tawm tias nws yuav siv LED backlights rau tag nrho nws cov phau ntawv sau thiab tshiab 24-inch Apple Cinema Display , thiab ib xyoos tom qab nws ua tswvcuab tshiab iMac , lub ntsiab lus ntawm tag nrho cov kua tshiab lub computer cov ntxaij tam sim no yog LED. Yuav luag txhua lub laptop nrog 16: 9 teeb duab pib txij thaum Lub Cuaj Hli Ntuj 2009 siv cov khoom siv hluav taws xob ntawm tes. Qhov no kuj yog rooj plaub rau feem ntau cov TV LCD TV, uas tau muag hauv qee lub teb chaws nyob hauv lub npe LED TV , tab sis cov duab tseem yog tsim los ntawm ib qho kev vaj huam sib luag hauv LCD.

Feem ntau cov LED backlights rau LCDs yog ntug-ntug , piv txwv li ob peb LEDs muab tso rau ntawm cov ntug ntawm lub teeb pom kev, uas faib cov teeb tom qab LC vaj huam sib luag. Qhov zoo ntawm cov txheej txheem no yog kev tsim kho vaj tse heev thiab vaj tse tsawg. Ib tus nqi kim dua yog hu ua puv lossis arraised LED thiab muaj ntau lub LEDs tso rau hauv qab ntawm LC vaj huam sib luag (ib qho array ntawm LEDs), xws li cov dav hlau loj tuaj yeem pom zoo. Qhov kev kho no tso cai rau lub zos dimming kom tau txais ib tsos tsaus tsawv dub pixels nyob ntawm cov duab tso tawm kom pom.

Backlight dimming

LED backlight feem ntau yog siv tswj cov ntaub ntawv xov xwm ^[14] (dynamic backlight control or dynamic "local dimming" LED backlight, kuj muag raws li HDR, siab dynamic TV, tsim los ntawm cov kws soj ntsuam ntawm Philips Douglas Stanton, Martinus Stroomer thiab Adrianus de Vaan ^{[ 15] [16] [17]} ).

Kev siv PWM (pulse-dav tes taws los piav, lub tshuab uas qhov kev siv ntawm cov LEDs khaws cia tas li, tab sis qhov kev hloov ua kom haum yog tiav los ntawm kev ua ib lub sij hawm luv ntawm flashing no qhov teeb ci qhov sib xws qhov chaw ^[18] ), lub backlight yog dimmed mus rau brightest xim uas tshwm ntawm qhov kev tshuaj ntsuam thaum ib txhij boosting tus LCD qhov sib txawv rau theem siab tshaj plaws

Yog hais tias qhov kev ntsuas ntawm qhov mem tes-dav hlau tsis tshua muaj qis los yog tus neeg siv cuab zog ua rau lub plab heev, qhov no yuav ua rau tsis xis nyob thiab qhov muag-mob, zoo ib yam li cov duab ntawm CRT . ^{[19] [20]} Qhov no tuaj yeem soj ntsuam los ntawm ib tus neeg siv los ntawm kev siv tes los yog khoom ua ntej ntawm qhov screen. Yog hais tias tus kwv zoo nkaus li muaj cov lus ceeb toom raws li nws tsiv lawm, qhov kev nrig qaum yog strobing rau thiab tawm ntawm lub sijhawm tsawg tsawg. Yog tias cov khoom zoo nkaus li zom zaws, qhov tso rau ntawm lub teeb pom kev los yog muaj lub teeb ci ntom nti tsis zoo los yog khiav hauj lwm ntawm lub teeb pom kev zoo dua li lub hlwb pom tau. Lub plhu yuav raug txo los yog tshem tawm los ntawm qhov kev teeb tsa kom pom qhov muag kom pom tag nrho, tab sis qhov no yuav muaj qhov tsis zoo rau cov duab zoo thiab roj teeb lub neej vim muaj zog ntau zog.