Ib, Cov yam ntxwv thiab kev sib tw tsav tsheb ntawm STN code breaking screen
1. Lub cev muaj zog ntawm hyper twisted nematic qauv
STN kua siv lead ua tau zoo txhim kho qhov kev sib hloov kho qhov muag los ntawm kev ua kom lub kaum sab xis ntawm cov kua siv lead ua kua molecules los ntawm 90℃ntawm TN hom mus rau 180℃-270 degree, optimizing cov xim tom qab ntawm daj ntseg ntawm TN rau xiav grey lossis daj ntsuab, thiab nce qhov sib piv rau 10: 1-20: 1. Txawm hais tias cov qauv no txhim kho cov kev ua tau zoo, nws tseem coj cov kev tswj hwm hluav taws xob ntau dua: cov kua siv lead ua kua molecules yuav tsum tau hloov pauv qhov zoo thiab qhov tsis zoo voltages kom tsis txhob muaj polarization, thiab cov tsav tsheb voltage waveform xav tau kom raug raws li cov lus teb cov yam ntxwv ntawm cov kua siv lead ua kua.
2. Inherent txwv ntawm passive matrix tsav
STN code breaking screen txais cov qauv passive matrix electrode, thiab nws txoj kev tsav tsheb yog qhov sib txawv ntawm cov active matrix TFT-LCD:
Tus naj npawb ntawm cov electrodes: A 16 × 2 cim STN screen yuav tsum muaj 32 SEG (segment) electrodes thiab 4 COM (common) electrodes, rau tag nrho ntawm 128 kev sib tshuam.
Dynamic scanning yuav tsum tau: Txhawm rau kom tsis txhob cuam tshuam kev cuam tshuam, txhua kab (COM) yuav tsum tau ua kom hloov pauv mus rau lub sijhawm- faib cov tshuab sib faib tshuab, nrog rau txhua kab teeb pom kev zoo tsuas yog 1/4 (1/4 lub voj voog lub luag haujlwm) lossis 1/8 (1/8 lub voj voog ua haujlwm) ntawm lub voj voog.
Kev tswj tsis zoo piv: Ntau theem voltage (xws li 1/3 thiab 1/2 bias) yuav tsum tau tsim los kho pixel transmittance thiab ua tiav cov zaub grey.
Kev sib tw engineering: Yog tias lub microcontroller IO tau siv ncaj qha los simulate tsav cov cim, ntau lub sijhawm AC waveforms yuav tsum tau tso tawm ib txhij, thiab qhov voltage amplitude yuav tsum tau hloov kho dynamically. Noj STM32F103 ua piv txwv, nws GPIO qhov tso zis ntau zaus tsuas yog 18MHz, uas nyuaj rau ua tau raws li 100Hz-400Hz scanning zaus feem ntau xav tau los ntawm STN cov ntxaij vab tshaus, thiab cov kev pab cuam nyuaj nce exponentially.
2, Kev soj ntsuam ntawm tus nqi tseem ceeb ntawm Dedicated Driver ICs
1. Kho vajtse qib optimization: los ntawm cov teeb liab tiam mus rau kev tswj fais fab
Cov neeg tsav tsheb tshwj xeeb ICs (xws li HT16K33, S6B33BOA) daws peb qhov teeb meem tseem ceeb los ntawm kev tsim qauv:
Waveform tiam: Tus tsim - hauv oscillator tuaj yeem tsim cov teeb liab AC tsav nrog kev hloov kho lub voj voog thiab kev tsis ncaj ncees, txhawb 1/2, 1/3, thiab 1/4 kev tsis ncaj ncees hom. Piv txwv li, sab hauv RC oscillator zaus ntawm HT16K33 tuaj yeem hloov kho mus rau 64Hz-512Hz los ntawm ib qho kev tiv thaiv sab nraud, zoo kawg nkaus phim cov kev xav tau tshiab ntawm STN cov ntxaij vab tshaus.
Kev tswj hluav taws xob: Kev sib koom ua ke twj tso kua mis lossis LDO regulator tuaj yeem tsim ± 12V tsis zoo voltage xav tau rau STN npo. Siv Samsung S6B33BOA ua piv txwv, nws lub twj tso kua mis sab hauv tuaj yeem txhawb nqa 3.3V cov tswv yim rau ± 15V, thiab qhov hluav taws xob ripple thaum tsav tsheb 65K xim STN screen tsawg dua 50mV.
Kev tswj lub sijhawm: Tau txais MCU cov lus qhia los ntawm I2C / SPI interface, tuaj yeem ua tiav thav duab scanning, cov ntaub ntawv xauv thiab lwm yam haujlwm. Noj 16 × 2 STN npo ua piv txwv, tus tsav tsheb IC tuaj yeem ua tiav puv npo refresh hauv 2ms, thaum lub microcontroller IO analog tsav tsheb yuav tsum muaj tsawg kawg yog 10ms thiab nquag mus rau ghosting.
2. Software theem Simplification: Los ntawm Register Configuration mus rau Ecological Support
Cov neeg tsav tsheb tshwj xeeb ICs txo qis kev txhim kho teeb meem los ntawm cov txheej txheem qhia:
RAM mapping technology: Piv txwv li, HT16K33 tau tsim - hauv 128 × 8-ntsis RAM, nrog rau txhua ntu sib txuas rau qhov chaw nyob ywj pheej. Cov kws ua haujlwm tsuas yog yuav tsum tau tswj qhov ci ntsa iab ntawm ib ntu los ntawm HT16K33WriteRAM (chaw nyob, cov ntaub ntawv) ua haujlwm, tsis tas yuav suav lub sijhawm.
Preset tsav hom: Mainstream tsav tsheb ICs (xws li RA8875) txhawb ntau hom zaub xws li hom cim, graphic dot matrix hom, thiab segment code hom, thiab tuaj yeem tswj cov logic nyuaj xws li cov cim hloov pauv hloov pauv thiab tus cursor positioning.
Kev txhawb nqa Toolchain: Cov neeg tsim khoom muab cov cuab yeej txhawb nqa PC teeb tsa (xws li Segger emWin), uas tuaj yeem pom cov ntaub ntawv tsim tawm thiab xa tawm raws li HEX cov ntaub ntawv pom tau los ntawm cov tsav tsheb ICs, txo qis kev loj hlob.
3, Feasibility ciam teb thiab siv scenarios ntawm kev tsav ncaj qha
1. Technical feasibility tej yam kev mob
Hauv cov xwm txheej tshwj xeeb, nws muaj peev xwm ua tau rau lub microcontroller ncaj qha tsav STN tawm ntawm lub vijtsam
Minimalist zaub yuav tsum tau: Yog tias tsuas yog ib qho me me ntawm cov cim ruaj khov (xws li 1-2 tus lej digital cov raj) yuav tsum tau muab tso tawm thiab cov kev xav tau tshiab thiab qhov sib txawv tsis siab, cov tsav tsheb zoo li qub tuaj yeem simulated los ntawm IO ports. Piv txwv li, siv PWM tso zis muaj nuj nqi ntawm STM32 los tsim ib tug square yoj nrog adjustable lub luag hauj lwm voj voog, tsav ib tug 2-tus lej 7-segment digital raj.
Kev txwv tus nqi qis: Hauv cov khoom siv roj teeb, yog tias nws tsis tuaj yeem them tus nqi ntawm cov tsav tsheb ICs (feem ntau
0.3−
1.5), lub tswv yim ntawm kev faib hluav taws xob tiv thaiv + IO simulation tuaj yeem txais yuav. Tab sis nws yog ib qho tsim nyog yuav tsum lees txais kev cuam tshuam hauv kev ua yeeb yam: 30% txo qis hauv qhov sib piv, tus nqi refresh<30Hz, and a high risk of ghosting.
2. Engineering Practice Case: Tsav Scheme rau kev ntsuas kub ntawm kev lag luam
Ib lub tuam txhab ib zaug sim siv STM32 ncaj qha tsav STN cov ntxaij vab tshaus hauv cov ntsuas kub, tab sis thaum kawg tau hloov mus rau ICs vim muaj teeb meem hauv qab no:
Lub sij hawm poob ntawm kev tswj: Nyob rau hauv qhov kub thiab txias ib puag ncig ntawm -20 degree, lub moos drift ntawm lub microcontroller ua rau scanning zaus poob los ntawm 120Hz mus rau 80Hz, uas ua rau flickering tseem ceeb.
Kev siv hluav taws xob ntau tshaj li tus qauv: Thaum IO analog tsav tsheb, lub microcontroller yuav tsum tau ua kom cov zis siab tsis tu ncua, thiab tag nrho lub zog siv ntawm lub tshuab nce los ntawm 2mA (raug muab IC daws) mus rau 15mA, txo lub roj teeb lub neej los ntawm 50%.
EMC cuam tshuam: Cov zis ncaj qha ntawm square waves los ntawm IO chaw nres nkoj ua rau siab - nrov nrov, ua rau kub sensor nyeem ntawv hloov pauv los ntawm ± 0.5 degree, tshaj qhov yuav tsum tau muaj.
