Tsev > Exhibition > Ntsiab lus

LCD-TFT ntxhais tsis

Oct 10, 2017

Ib, LCD kev faib tawm

(1) STN

Super Twisted Nematic, super twisted nematic, CSTN thiab DSTN, yog ib qho ntawm lub vijtsam tsis tshua muaj siab kawg hauv 4, tsuas yog qhov zoo ntawm kev siv zog tsawg, lub sijhawm teb yog kwv yees li 200ms.

(2) TFT

Nyias zaj duab xis Transistor nyias zaj duab xis transistor. Lub hwj huam noj tau yooj yim dua, lub sij hawm teb yog li 80ms.

(3) LTPS

Tsawg Hlis Polycrystalline Silicon, tsis tshua muaj kub hnyiab. Muab tau los ntawm TFT ntawm ib tiam tshiab ntawm cov khoom, lub sij hawm teb yog txog 12ms. vim yog qhov tsim ntawm lub vijtsam sab hauv siab yog siab tshaj qhov ntawm cov khoom tsim tau TFT npo, tam sim no tsuas muaj tsawg tsawg ntawm cov chaw tsim khoom lag luam uas tsim tau.

(4) OLED

Organic Light Emitting Diode, organic light-emitting diodes, qhov pom lub kaum ntse ntse loj heev, lub hwj huam yog tsawg heev, yog lub hauv paus ntawm txoj kev loj hlob yav tom ntej.

   二, LCD parameter

(1) qhov ntev

General LCD npo siv qhov ntev ntawm kab pheeb ces kaum sawv cev qhov luaj li cas ntawm qhov screen, hauv inches.

(2) daws teeb meem (Resolution)

Tus duab hu ua ib kablus (ncej), txhua kab ntawv muaj ntau hom kab thiab pixels txhua. Qhov kev daws teeb meem yog raws li nram no:

320 * 240 (QVGA) 640 * 480 (VGA) 800 * 480 (WVGA)

800 * 600 (SVGA) 1280 * 800 (WXGA)

(3) PPI

Pixels ib nti. nyob hauv daim duab, pes tsawg tus pixels ib nti muaj qhov tseem ceeb cwj pwm tseem yog qhov kev piav qhia ntawm daim duab duab. PPI nqi siab, daim duab ntau nplua nuj nthuav dav. Hom PPI qhov tseem ceeb yog 72ppi, 180ppi, 300ppi.

(4) xim tob (xim xim)

Cov xim ntawm txhua tus pixel siv cov ntaub ntawv binary cov ntaub ntawv los sawv cev, chav tsev yog BPP (me ntsis ntawm pixel). Cov xim uas sib sib zog nqus:

<1> 8BPP: 2 ^ 8 = 256 xim, xim ntawm txhua tus pixel siv cov duab 8 npawb hauv binary, piv txwv li lub pixel muaj 256 xim thiab peb cov xim thawj. Tab sis qhov nruab nrab, txhua xim tsuas yog siv tsawg tshaj 3 cov khoom ntawm cov ntaub ntawv uas txhua xim ntau dua 8 theem, qhov no tsis txaus los hais ntau xim nplua nuj. Yuav kom daws tau qhov teeb meem, yuav tsum tau hu rau palette. Cov ntaub ntawv 8 ntsis sib nug xov mus rau txhua tus pixel ntawm RGB tsis tau hais dua peb ntawm cov thawj xim, thiab nws cov qhabnias hauv tus nqi palette. Mus tso saib pixel, siv qhov Performance index uas tau txais RGB xim ntawm cov xim palette.

<2> 16BPP: 2 ^ 16 = 65k xim, hu ua pseudo colour, cov xim ntawm txhua pixel siv cov duab 16bit binary binary, piv txwv li ib pixel 65K txawv xim. Cov xim ntawm txhua tus pixel siv ob tug bytes, ob tug bytes ntawm cov ntaub ntawv yog muab faib ua ob hom: 5: 6: 5, 5: 5: 5: 1, tus qub siab 5 liab, nruab nrab 6 hais tias ntsuab, qis 5 sawv cev xiav; qhov tom kawg 15 los ntawm siab mus rau qis yog faib ua 3 5 khoom rau xim liab, ntsuab, xiav, qis qis. Yog li no, 5: 5: 5: 1 hom ntawv thiab hom ntawv RGBA (hu ua A: Alpha, said transparency).

<3> 24BPP: 2 ^ 24 = 16M xim, hu ua tseeb xim, txhua lub binary pixel xim uas siv cov 24bit hais tias pixel 16M txawv xim. Cov xim ntawm txhua lub pixel siv peb bytes, txhua lub xim xim siv 8 xuab moos, LCD maub los ntawm VD [23: 0] cable mus rau LCD. nyob rau hauv thiaj li yuav pab txhawb cov kis ntawm DMA. 4 bytes sawv cev rau pixel hauv lub cim xeeb, thiab 3 bytes los ntawm siab mus rau qis yog xim liab, ntsuab thiab xiav, ib qho ntawm cov bytes ntxiv yog qhov tsis muaj tseeb. Qhov qis tshaj plaws los yog qhov siab tshaj byte yog qhov tseeb, nws yog qhov xaiv tau.

[saib]

Tus nab npawb ntawm bytes LCD duab cov ntaub ntawv, los sis = pixels * cov nab npawb ntawm bytes uas yog daim duab ntawm qhov sib sib zog nqus xim

Xws li 16BPP 320 * 240 LCD, = 320 * 240 * 2 = 153600 cov naj npawb ntawm bytes ntawm cov ntaub ntawv thav duab

(5) pointing bitmap

Bitmap txoj kev yog duab ua ntau pixels, txhua pixel nrog ib qhov khoom ntawm cov khoom pixel xim, ci ntsa iab thiab cov cwj pwm. Yog li tus duab ua los ntawm ntau cov lus piav qhia ntawm txhua cov ntaub ntawv pixel. Cov ntaub ntawv no feem ntau hu ua cov duab cov ntaub ntawv, thiab cov ntaub ntawv no feem ntau yog cov ntaub ntawv khaws cov ntaub ntawv, qhov no kuj hu ua daim duab duab.

(6) lub ntsiab xim

Raws li lub hauv paus ntsiab lus ntawm cov xim, txhua yam xim ntawm lub ntiaj teb no tuaj yeem tov los ntawm kev sib txawv ntawm cov xim ntsuab thiab xiav peb xim ua ke, cov xim peb hu ua xim los yog xim.

(7) grey scale

Grey yuav xav tias nws yog ci ntsa iab, ci ci rau txhua qhov xim. Cov xim ci raws li qhov kev siv ntawm kev faib, yog qhov txho. Qhov siab dua cov khoom ntsuas ntawm cov xim muaj peev xwm ua tau, cov duab xim ntau dua, tab sis tus nqi kuj tseem siab dua. Piv txwv li:

4 (= 2 ^ 2) gray xim, txhua xim siv 2bit, tuaj yeem tso xim rau (2 ^ 2) * (2 ^ 2) * (2 ^ 2) = 64

16 (= 2 ^ 4) gray colour, txhua qhov xim siv 4 lis, tuaj yeem pom cov xim rau (2 ^ 4) * (2 ^ 4) * (2 ^ 4) = 4096

256 (= 2 ^ 8) gray colour, txhua xim siv 8b, tuaj yeem tso xim rau (2 ^ 8) * (2 ^ 8) * (2 ^ 8) = 16777216

Raws li qhov muaj zog ntawm cov xim ntawm peb lub ntsiab xim yog muab faib ua 256 theem (0-255), koj tuaj yeem siv 255 qib 255 qib liab, xiav, 255 ntsuab dawb; siv tau qib 0 qib 0 liab, xiav, ntsuab 0 ua ke dub.

三, TFT_LCD interface
Qhov cim npe Lub npe piav qhia

VSYNC Ncej (ntsug) qhov teeb meem kev sib txuas Ua dua qhov pib ntawm ib kab lus (screen)

HSYNC kab rov tav (kab rov tav) Sawv cev thaum pib ntawm qhov sib txuas ntawm cov lus sib dhos

HCLK Pixel lub teeb liab Tsom kwm cov ntaub ntawv uas tau kis los ntawm ib lub pixel

VD [23: 0] cov ntaub ntawv teeb liab Kev qhia cov teeb liab mus txog 16M xim

LEND Line kawg lub teeb liab Uas yog nruab nrab ntawm qhov kawg ntawm kab ntawv

VM (VDEN) Cov ntaub ntawv siv tau tseeb Nyob hauv cov ntaub ntawv siv mus los, lub teeb liab raug tso 1

PWREN Fais fab teeb liab Qhov hluav taws xob hloov teeb liab

四, TFT_LCD sib lawv liag

图片1.png

Ib nrab ntawm ib nrab ntawm cov duab sib lawv liag yog ib qho luam ntawm cov cwj pwm coj

(1) VSYNC teeb liab, nruab nrab yog pib ntawm ib kab lus ntawm cov ntaub ntawv.

(2) VSPN VSYNC pulse width signal rau (VSPW + 1) HSYNC (VSPW + 1). Lub voj voog cov teeb meem rau cov ntaub ntawv tsis muaj tseeb.

(3) thiab tom qab (VBPD + 1) HSYNC teeb liab, rau cov ntaub ntawv zoo los tshwm. Yog li no, VSYNC teeb liab, tab sis kuj tom qab tag nrho (VSPW + 1 + VBPD + 1) tsis muaj tseeb, ces thawj kab ntawv tsuas yog (VDEN teeb liab, yog cov ntaub ntawv siv tau, tsis li ntawd nws yuav raug suav hais tias tsis muaj tseeb cov ntaub ntawv).

(4) tom qab muab cov kab ntawv sib law liag (LINEVAL + 1).

(5) thiab (VFPD + 1) tsis muaj tseeb. Kev ua tiav kawg ntawm tus ncej kawg, raws li cov xwm txheej ntxiv tom qab. Qhov ntawd yog VSYNC teeb liab.

Qhov qis dua ib nrab ntawm cov duab kos yog ib daim duab ntawm pixels hauv txhua kab

(1) HSYNC teeb liab, nruab nrab yog pib ntawm kab kev qhia.

(2) HSPW tau hais tias qhov laj thawj ntawm HSYNC teeb liab mus rau VCLK teeb liab (HSPW + 1). Cov voj voog no (HSPW + 1) pixel cov ntaub ntawv tsis muaj tseeb.

(3) thiab tom qab (HBPD + 1) VCLK lub voj voog teeb, cov ntaub ntawv pixel zoo tuaj. Yog li, HSYNC teeb liab, tab sis kuj tom qab tag nrho (HSPW + 1 + HBPD + 1) tsis pixels, ces thawj zaug pixel tsuas (VDEN teeb liab teeb, yog pixels zoo.) Yog tias tsis yog nws yuav pom tias pixels invalid).

(4) tom qab muab cov kab sib law liag (HOZVAL + 1) sib law liag.

(5) thiab (HFPD + 1) tsis pixels. Qhov kawg ntawm txoj kab tiav, ua raws li ntawm kab lus. Qhov ntawd yog HSYNC teeb liab.

[saib]

Los ntawm TFT_LCD cov kab kos duab qhia tau hais tias nyob rau hauv kev ua hauj lwm ntawm cov zaub, pom ncig lub ciam teb dub. Lub npov dub saum toj no yog vim hais tias thaum lub teeb liab VSYNC, yuav tsum tau los ntawm ntau tus kab tom qab thawj kab ntawm cov ntaub ntawv siv tau. Lub npov dub hauv qab cov duab kawg vim hais tias tag nrho cov kab ntawm cov ntaub ntawv thaum VSYNC cov teeb liab tsis muaj cov ntaub ntawv tau muab, lub thawv ntim ntawm sab laug yog qhov tseeb. Vim tias thaum muaj HSYNC teeb liab, xav tau los ntawm ntau hom pixels tom qab kab ntawv thawj ntawm cov ntaub ntawv siv tau. Lub thawv dub ntawm sab xis yog vim cov ntaub ntawv kawg ntawm cov kab ntawv kab, cov zaub tsis yog xa mus rau sab xis (HSYNC teeb liab tsis tau muab), ces cov ntaub ntawv tsis muaj tseeb. Nco ntsoov tias cov zaub yuav tsuas yog raws li VSYNC, HSYNC teeb liab daim duab, tso cov ntaub ntawv, tsis hais seb cov ntaub ntawv puas siv tau, thaum cov ntaub ntawv siv tau los ntawm cov duab.

VSYNC teeb liab lub sijhawm ntawm qhov hais tias 1s tuaj yeem pom ntau npaum li cas cov duab, hu ua feem ntau ntawm qhov feem pua lossis feem ntau ntawm daim teb.HSYNC teeb liab, nws feem ntau hais tias qhov tso tawm zaus hu ua zaus ntau tshaj.

Cov ntaub ntawv muaj tseeb ntawm tus lej thiab tus lej ntawm tus lej, uas yog qhov kev daws teeb meem ntawm nws thiab VSYNC, HSYNC teeb liab raug teeb tsa, cov hauj lwm no yog ua los ntawm daim card graphics.