Lub ci ci ntawm ib qho screen loj LED yog tsau thiab feem ntau tswj tsis tau. Txawm li cas los xij, theoretically, muaj ob txoj kev tswj hwm:
1. Daim npav txais daim npav serially xa tsis tau lub teeb liab rau / tawm rau txhua lub LED, tab sis tus nqi 8-ntsis binary brightness. Txhua LED muaj nws tus kheej pulse dav modulator los tswj nws lub sijhawm teeb pom kev zoo.
Yog li, nyob rau hauv ib lub voj voog rov qab teeb pom kev zoo, txhua lub pixel yuav tsum tsuas yog 4 pulses rau 16 qib greyscale thiab tsuas yog 8 pulses rau 256 qib greyscale, txo qhov kev sib kis ntau zaus. Qhov kev faib tswj ntawm LED greyscale tau yooj yim ua tiav 256-theem greyscale tswj.
Ib txoj hauv kev suav nrog kev hloov pauv tam sim no ntws los ntawm LED zaub screen. Feem ntau, cov raj LED tuaj yeem ua haujlwm tsis tu ncua ntawm thaj tsam 20 mA. Tsuas yog cov xim liab -chip LEDs uas muaj qhov saturation, qhov ci ntsa iab ntawm lwm cov raj LED yog qhov sib piv rau qhov tam sim no ntws los ntawm lawv.
Txoj kev no siv qhov pom kev tsis pom kev thiab tsis pom kev pom ntawm tib neeg lub qhov muag, siv pulse width modulation (PWM) kom ua tiav greyscale tswj. Qhov no suav nrog hloov pauv qhov dav ntawm lub teeb mem tes (piv txwv li, lub voj voog lub luag haujlwm). Ntev npaum li qhov teeb pom kev rov ua dua tshiab no luv luv txaus (piv txwv li, tus nqi refresh yog siab txaus), tib neeg lub qhov muag tsis tuaj yeem pom qhov flickering ntawm lub teeb -emitting pixels.
Vim tias PWM yog qhov tsim nyog rau kev tswj hwm digital, yuav luag txhua qhov LED qhia hnub no siv PWM los tswj cov qib grey, tshwj xeeb tshaj yog vim cov tshuab microcomputers feem ntau siv los muab cov ntsiab lus tso tawm ntawm cov ntxaij vab tshaus LED.
Cov ntaub ntawv txuas ntxiv: Ib qho kev tswj hwm LED feem ntau muaj peb qhov tseem ceeb: lub thawv tswj lub ntsiab, lub tshuab luam ntawv, thiab cov khoom siv tswj. Lub thawv tswj lub ntsiab tau txais cov ntaub ntawv xim ci ci ntawm lub vijtsam pixels los ntawm lub khoos phis tawj daim npav duab, thiab tom qab ntawd rov faib nws mus rau ntau lub scanning boards. Txhua lub scanning board yog lub luag hauj lwm rau kev tswj ob peb kab (kem) ntawm lub LED screen, thiab cov zaub tswj cov cim qhia rau txhua kab (kem) ntawm LEDs yog kis serially.
Tam sim no, muaj ob txoj hauv kev rau serially transmitting zaub tswj cov cim: ib qho yog tias cov scanning boards centrally tswj cov grayscale ntawm txhua pixel. Lub scanning boards decompose lub brightness qhov tseem ceeb ntawm txhua kab ntawm pixels los ntawm lub thawv tswj (xws li, mem tes dav modulation), thiab ces xa cov LED on / off signals ntawm txhua kab ntawm LEDs nyob rau hauv daim ntawv mem tes (1 rau lit, 0 rau unlit) serially rau cov coj LEDs, tswj seb lawv puas.
Txoj kev no siv cov khoom siv tsawg dua, tab sis cov ntaub ntawv xa mus ua ntu loj dua vim tias, nyob rau hauv lub voj voog rov qab teeb pom kev zoo, txhua pixel xav tau 16 pulses rau 16 qib greyscale thiab 256 pulses rau 256 qib greyscale. Vim muaj kev txwv ntawm cov cuab yeej ua haujlwm zaus, LED npo feem ntau tsuas yog ua tiav 16 qib greyscale.
Txoj kev no siv cov khoom tsawg dua, tab sis xa cov ntaub ntawv ntau heev. Qhov no yog vim hais tias txhua pixel xav tau 16 pulses ntawm 16 qib grey thiab 256 pulses ntawm 256 grey theem nyob rau hauv ib lub voj voog ntawm rov illumination. Vim muaj kev txwv ntawm cov cuab yeej ua haujlwm zaus, LED cov ntxaij vab tshaus feem ntau tsuas yog ua tiav 16 qib grey.
