Cov zaub zoo ntawm LED zaub yeej ib txwm muaj feem cuam tshuam nrog kev tsav tsheb tam sim no, hais txog cov teeb meem xws li ghosting, tuag pixel crosshairs, qis greyscale xim hloov, tsaus ua ntej scan, thiab siab sib txuas sib txuas. Kab rov tav tsav, raws li qhov yuav tsum tau luam theej duab yooj yim, ib txwm tau txais kev saib xyuas tsawg dua. Nrog rau kev txhim kho ntawm cov teeb pom kev me me LED, kev xav tau ntau dua tau muab tso rau ntawm kab rov tav tsav, hloov los ntawm P-MOSFETs yooj yim rau kab rov tav hloov mus rau ntau qhov sib xyaw thiab muaj zog ntau- cov tsav tsheb tav toj. Kev tsim thiab xaiv cov neeg tsav tsheb kab rov tav tseem ntsib rau 6 qhov kev sib tw loj: kev tshem tawm ghosting, rov qab voltage ntawm LED chips, luv- teeb meem hauv Circuit Court, qhib-circuit crosshairs, siab heev VF qhov tseem ceeb ntawm LED chips, thiab siab sib txuas coupling.
Dab Ntxwg Nyoog
Thaum hloov ntawm cov ntxaij vab tshaus scanning, vim lub sij hawm yuav tsum tau rau PMOS transistor keyboards tig rau thiab tawm, thiab rau tus nqi kom dissipate ntawm parasitic capacitance Cr ntawm kab kab, undischarged nqi ntawm VLED los ntawm kab yav dhau los scan muaj ib tug conductive txoj kev nyob rau hauv lub instant VLED thiab OUT ntawm kab tom ntej scan yog qhib. Thaum Row(n) qhib, tus kab mob parasitic capacitance Cr ntawm kab raug them rau VCC peev xwm. Thaum hloov mus rau Kab (n+1), qhov sib txawv muaj peev xwm tsim ntawm Cr thiab OUT, thiab tus nqi raug tso tawm los ntawm LED, ua rau lub teeb ci ntsa iab.
Yog li ntawd, tus nqi ntawm Cr capacitor yuav tsum tau tso tawm ua ntej ntawm lub sijhawm so. Feem ntau, kab rov tav tso zis transistor nrog kev sib xyaw ua ke ua haujlwm siv lub rub -down Circuit Court kom sai sai tshem tawm cov nqi ntawm cov kab mob parasitic capacitance Cr thaum hloov. Qhov qis dua qhov rub -down muaj peev xwm, piv txwv li, qhov blanking voltage VH, tau teeb tsa, qhov nrawm dua ntawm tus kab mob parasitic capacitance raug tso tawm, thiab qhov zoo dua cov txiaj ntsig ntawm kev tshem tawm sab sauv dab. Feem ntau, VH < VCC - 1V txaus los tshem tawm cov dab saum toj kawg nkaus.
LED rov qab voltage
Qhov rov qab qhov hluav taws xob hluav taws xob ntawm LED chips cuam tshuam rau lawv lub neej, thiab pixel tsis xws luag tshwm sim los ntawm qhov hluav taws xob rov qab ib txwm yog ib qho kev txhawj xeeb loj rau LED zaub, tshwj xeeb tshaj yog cov me me -pitch displays.
Thaum cov zis channel tawm lawm, cov kab mob parasitic inductance lub freewheeling tam sim no txuas ntxiv tsub tus kab mob parasitic capacitance ntawm cov channel, tsim kom muaj hluav taws xob siab. Qhov no spikes, ua ke nrog cov kab rov tav tso zis transistor (HIP), ua ib qho hluav taws xob rov qab hla ntawm LED nti. Yog li ntawd, HIP's blanking voltage kuj cuam tshuam rau LED nti rov qab voltage. Nrog rau qhov ntsuas hluav taws xob tas li ntawm qhov tso tawm tam sim no, qhov siab dua HIP blanking voltage ua rau qis rov qab voltage rau LED nti. Thaum LED chips feem ntau muaj qhov nominal thim rov qab voltage ntawm 5V, cov chaw tsim khoom kuaj tau pom tias qhov hluav taws xob rov qab qis dua 1.4V tuaj yeem txo qhov tsis zoo ntawm pixels los ntawm qhov rov qab voltage. Yog li ntawd, lub blanking voltage yuav tsum tsis txhob tsawg dhau los hais txog LED nti rov qab voltage teeb meem, feem ntau tsis qis dua VCC-2V.
Luv- kab ntsig kab ntsig
Thaum lub LED luv luv -circuited, ib kab ntawm cov LEDs tas li yuav tshwm sim, feem ntau hu ua luv luv - kab ntsig kab ntsig. Thaum nruab nrab LED luv luv -circuited, LEDs nyob rau hauv tib kab yuav tsim ib txoj kev raws li qhia nyob rau hauv daim duab hauv qab no thaum scanning kab. Yog tias qhov sib txawv ntawm qhov sib txawv ntawm VLED thiab point A yog ntau dua li LED qhov teeb pom kev zoo, ib kab ntawm cov kab ntsig tas li yuav raug tsim.
Qhov sib txawv loj tshaj plaws ntawm luv luv - kab ntsig kab ntsig thiab qhib - Circuit Court cross yog luv luv - kab ntsig kab ntsig yuav tshwm sim ntev npaum li qhov screen nyob rau hauv hom scanning, tsis hais seb cov hlaws LED puas pom cov duab, thaum qhib - kab ntsig kab ntsig - tsuas yog qhia qhov qhib hla teeb meem thaum qhib -circuit LED hlaws yog teeb. Qhov no feem ntau yog daws los ntawm kev ua kom cov kab rov tav tso zis transistor lub blanking voltage kom qhov sib txawv voltage tsawg dua li LED lub pem hauv ntej voltage VF, piv txwv li, VLED - VH < VF. Feem ntau, rau pem hauv ntej voltage VF rau liab LED hlaws yog 1.6 ~ 2.4V, thiab rau ntsuab thiab xiav LED hlaws nws yog 2.4 ~ 3.4V. Kev ntsuam xyuas pom tias cov hlaws liab LED tuaj yeem teeb nrog 1.4V; Yog li ntawd, siv cov hlaws liab LED ua piv txwv, thaum VH > VCC - 1.4V, luv luv - teeb meem kab ntsig kab ntsig tau daws tag nrho. Thaum VCC - 2V < VH < VCC - 1.4V, tsuas yog ib lub LED liab hauv qab lub luv luv - lub voj voog taw tes tsis muaj zog.
Qhib Hla
Thaum qhib - LED Circuit Court tshwm rau ntawm qhov screen scanning thiab qhov taw tes ntawd tau teeb, qhov voltage ntawm channel OUT1 yog rub mus rau qis dua 0.5V. Yog hais tias qhov blanking voltage VH ntawm qhov scanning kab muaj peev xwm yog 3.5V, ib txoj kev conductive yuav raug tsim rau cov kab ntawm LEDs, tsim ib qho qhib -circuit "cav" nyhuv.
Thaum lub LED qhib -circuited, qhov voltage ntawm channel OUT1 yog rub mus rau hauv qab 0.5V lossis txawm 0V. Qhov no cuam tshuam rau kab cab kab mob Cr los ntawm kab mob cab C1 thiab C2. Thaum lub peev xwm ntawm Cr raug rub qis, LEDs nyob rau hauv tib kab raws li qhov qhib -circuited LED yuav dim.
Txo qhov blanking voltage ntawm kab rov tav tso zis transistor (tso tawm transistor) tuaj yeem daws tau qhov qhib - teeb meem ntawm qhov hluav taws xob, piv txwv li, blanking voltage VH < 1.4V. Qee qhov tso zis transistors hauv kev lag luam kuj tseem siv cov hluav taws xob hloov kho kom txo qis qhov hluav taws xob qis dua 1.4V los daws qhov qhib - qhov teeb meem ntawm qhov hluav taws xob, tab sis qhov no yuav ua rau cov hluav taws xob rov qab ntawm LED, ua kom muaj kev puas tsuaj ntawm LED, thiab ua rau luv luv Circuit Court.
Tus nqi VF ntawm LED yog siab dhau.
Qhov teeb meem ntawm cov kab uas tseem tshuav tsis tu ncua vim qhov muaj txiaj ntsig VF ntau dhau hauv LEDs yog lwm qhov teeb meem uas plagues cov neeg siv. Feem ntau, qhov nominal rau pem hauv ntej voltage VF ntawm ib tug ntsuab LED yog 2.4 ~ 3.4V. Nquag, qhov sib txawv ntawm qhov sib txawv ntawm 1.8V ntawm lub anode thiab cathode ntawm ntsuab LED yog txaus los teeb nws. Txawm li cas los xij, ib qho hluav taws xob ntau dhau ntawm VH ntawm kab rov tav tso zis transistor yuav ua rau kem kom nyob twj ywm tsis tu ncua.
Noj ib qho LED nrog rau pem hauv ntej voltage VF1=3.4V ua kem, thaum scanning mus txog rau tom ntej no LED, VOUT thiab VLED1 tig rau ib txhij. Channel davhlau ya nyob twg voltage yog: VOUT=VLED1 - VF1. Cov voltages hla lwm cov LEDs hauv kab ntawv yog: VΔ=VH - VOUT=VH - VLED1 + VF1. Yog tias VΔ > 1.8V, nws yuav ua rau cov kab txuas txuas mus tas li, piv txwv li, VH - VLED1 + VF1 > 1.8V, qhov twg VLED=VCC (tsis quav ntsej cov kab rov tav tso zis transistor voltage poob). Yog li ntawd, VH > VCC - 1.6V tsis yog qhov tsim nyog los daws qhov teeb meem ntawm cov kab uas tseem tshuav tsis tu ncua vim qhov muaj txiaj ntsig VF ntau dhau hauv LEDs.
High contrast coupling
High contrast coupling yog hais txog qhov tshwm sim uas cov duab ci yog superimposed nyob rau hauv qis -brightness tom qab, ua rau xim hloov thiab darkening nyob rau hauv qhov chaw uas qhov tsawg - brightness thiab ci - brightness dluab yog sib npaug, raws li qhia los ntawm kab dotted nyob rau hauv daim duab saum toj no, uas sawv cev rau superimposed ci duab. Qhov sib txawv siab sib txuas no yog tshwm sim los ntawm kev cuam tshuam ntawm kab kem los ntawm cov kab rov tav tso zis transistors. Nws tuaj yeem txo qis rau qee qhov los ntawm kev tsim lub clamping voltage, tswj nws ntawm qee theem tom qab tso tawm, yog li txo qis cov kab rov tav tso tawm transistor lub blanking voltage. Txawm li cas los xij, txoj kev tsim qauv no qhia txog cov teeb meem xws li luv luv- kab hluav taws xob kab hluav taws xob tsaus nti, qis- thaj chaw grey tshwm liab liab, thiab cov nqi VF siab heev rau LEDs. Kev txhim kho qhov sib txawv ntawm qhov sib txawv ntawm qhov kev xav ntawm kab rov tav tsav tuaj yeem ua tiav los ntawm kev txo qis qhov tsis muaj hluav taws xob, tab sis qhov no ua rau muaj qhov hluav taws xob rov qab ntau dhau rau cov LEDs thiab "cav" luv luv - teeb meem hauv Circuit Court.
Xaiv cov kab rov tav tso zis blanking voltage
Hauv cov ntsiab lus, xaiv qhov blanking voltage rau kab rov tav tso zis transistor (HIP) ntsib cov teeb meem cuam tshuam nrog rau rau qhov teeb meem tau hais los saum no, txhua tus muaj nws tus kheej cov teeb meem tshwj xeeb. Lub blanking voltage tsis tuaj yeem siab dhau lossis qis dhau. Feem ntau, qhov qhib -circuit crosshair raug tshem tawm los ntawm kev tshawb pom qhov tsav tam sim no, vim tias qhov hluav taws xob qis qis dhau los txo qhov kev cia siab ntev ntawm LED. Cov lus hauv qab no qhia txog qhov tsim nyog ntawm qhov hluav taws xob blanking nyob rau hauv ntau yam mob.
Yog li ntawd, xav txog ntau yam teeb meem ntawm daim ntawv thov, qhov hluav taws xob blanking ntawm 3V ~ 3.4V (VCC=5V) yog qhov kev xaiv tsim nyog. Qhov no tuaj yeem ua tau raws li cov qauv tsim ntawm ntau cov qauv scanning thiab yog li tsim nyog daws tau ntau yam teeb meem ntawm daim ntawv thov.
