Tsev > Exhibition > Ntsiab lus

Cov kua siv lead ua kua

Jun 28, 2018

Cov kua siv lead ua kua

1. kua crystal qhia luv luv

Nyob rau hauv 1888, tus kws tshawb fawb Australian, Leni FM, coj los ua ib qho kev sib txawv ntawm cov organic, uas muaj ob lub ntsiab lus melting. Thaum cov khoom siv lead ua kom sov tau mus rau 145, nws yaj ua kua, tiam sis nws tsuas yog pos huab, thiab tag nrho cov ntshiab cov khoom tau los thaum lawv melted. Yog hais tias nws tseem sov mus txog 175 degrees, nws zoo li yaj dua thiab ua kua thiab tshau kua. Tom qab ntawd, Lehman, German physicist, hu ua turbid kua hauv "nruab nrab tsam" hu ua crystal. Nws zoo li ib tug tub qhe tsis nyiam ib tug nees los yog ib tug nees luav, yog li ntawd nws yog hu ua ib qho ntshav siab. Txij li cov kua siv lead ua kua, cov neeg tsis paub tias nws yuav siv li cas txog 1968, tib neeg tau muab nws ua ib yam khoom hauv kev lag luam hluav taws xob.

Lub xeev ntawm feem ntau ntawm cov tshuaj nrog me me molecular luj nthuav txog peb lub xeev ntawm qhov teeb meem nrog kev nce ntawm kub - khoom (solid), kua (kua) thiab roj (roj). Tab sis yog tias qhov hnyav ntawm lub cev loj yog qhov loj thiab cov qauv yog tshwj xeeb, qhov hloov ntawm nws lub xeev tsis yog li yooj yim. Xyoo 1888, thaum Reinizer tau rhaub rau lub pob txha hauv chiv nyhav, nws tau pom tias thaum heated rau 145.5 degrees, nws muab tso rau hauv ib lub pos huab dawb nplaum, uas hloov mus ua kua dej thaum uas rhuab mus rau 178.5 degrees. Lehman pom tau hais tias lub xeev ntawm cov siv lead ua kua thiab cov kua dej (theem) muaj qhov pom kev zoo ntawm cov khoom siv hauv lub cev, nws yog lub npe hu ua kua siv lead ua kua (kua siv ua kua). Cov kua siv lead ua kua (kua siv lead ua kua) yog cov kua hluav taws xob thiab siv lead ua, qhia tau hais tias cov kua muaj qhov dej (fluidity) thiab kuj muaj cov cim kho qhov muag uas tsis zoo (anisotropy optical) tib lub sijhawm. Vim hais tias nws tshwm sim hauv lub xeev ntawm cov khoom thiab kua, nws yog qhov tseeb tshaj yog hu rau nws lub npe (mesophase), tab sis feem ntau nws yog hu ua kua Crystal.

Nrog txoj kev tshawb fawb, kua crystal theem tau pom nyob hauv ntau cov tshuaj, thiab cov molecules nrog kua siv lead ua kua tau pom tias muaj cov txheej txheem molecular zoo ib yam los yog cov kab tawm suab (thov saib daim duab 1). Raws li pom hauv daim duab 2, cov khoom siv ua kua ua kua ua kua muaj txheej txheem ua raws li qee txoj cai ntawm qee yam qis, tab sis thaum twg lub ntsiab lus ntawm qhov nruab nrab (qhov pib ntawm qhov chaw), qhov chaw ntawm kev txav ceev, tab sis kev taw qhia ntawm lub bar tsim ib qho kev faib tawm ntawm lub cev anisotropic kua (anisotropic kua). Nws yog cov kua qaub ua kua. Qhov no yog lub ntsiab tseem ceeb vim li cas cov kua nplaum yuav muaj kev pom zoo anisotropy. Yog hais tias qhov kub siab tuaj nyob rau lub sijhawm no (qhov chaw clearing), cov roj molecules tsis tsuas yog qhov chaw ntawm cov huab cua, tab sis qhov kev taw qhia ntawm lub pluaj yog dawb faib, thiab ua kua yogotropic (isotropic kua).

1.png


2.png

Daim duab 1. piv txwv ntawm cov kua siv lead ua kua molecular qauv, nematic kua siv lead ua 5CB thiab cov kua hluav taws xob ua kua dej ua kua DOBAMBC


3.png

 

(khoom: crystalline) (kua: anisotropic kua) (kua: isotropic kua)


Daim duab 2. raws li kev faib khoom thiab kev tsim kho ntawm cov qauv (theem).

(1) hom kua siv lead ua kua

Cov khoom siv ua kua ua kua muaj peev txheej ua tau rau ntau theem ntawm cov qauv los yog cov khoom tshwj xeeb, raws li tau hais yav tas los, nws muab faib ua kua crystalline (lyotropi) kua siv ua kua (lyotropi) nrog kua crystal theem thaum cov kua Crystal theem (thermotropic Crystal) nrog kua crystal theem hauv ib cheeb tsam ntawm cov kub thiab ib qho kev faib ua feem ntawm qhov hnyav hauv ib qho hnyav (lyotropi) C kua siv lead ua). Feem ntau cov kua nplaum uas siv los tso rau hauv cov khoom yog cov kua thermotropic cov kua, thiab cov kua lyotropic kua muaj feem ntau pom muaj hauv biofilms. Cov kua dej muaj peev xwm muab faib ua cov nematic (nematic), cholesteric (cholesteric) thiab ze crystalline (smectic) raws li lawv txoj haujlwm txoj haujlwm (qhov chaw nyob) thiab kev txiav txim siab (qhov kev txiav txim siab).

Nematic kua siv lead ua kua (kua roj kua nematic kua)

Qhov chaw ntawm cov nematic kua siv lead ua kua molecules yog txav xws li ib cov kua, thaum lub siab ntev ntawm txoj kab (molecular axis ntev) ntawm lub molecule muaj lub caij cua kub viav tab sis yog tusyees qhia nyob rau hauv ib qho kev taw qhia. Chav tsev vector tau teev nyob rau hauv qhov kev taw qhia no yog hu ua tus tswj (tus thawj coj). Yuav luag tag nrho cov cev nqaij daim tawv ntawm lub cev muaj zog ntawm cov kua nematic kua yog ib txoj kab nkaus xwb (uniaxial) nyob ntawm txoj kab sib txawv ntawm cov maub los. Tsis tas li xwb, tus maub los yog tsis ua kom haum ua ntej thiab tom qab (lub taub hau kom paub qhov sib npaug), yog li ntawd txawm tias nws cov khoom sib cais muaj polarity (polarity), tsis muaj polarity hauv cov kua nematic kua. Txawm hais tias nws cov qauv yog simplest rau peb hom kua muaju, feem ntau cov kua nplaum uas siv hauv cov ntsuas yog cov kua nematic kua. Nws yog tsuas yog qhia nyob rau hauv N.

4.png


Xam phaj 3. hom ua kua dej ua kua

cov roj siv lead ua kua cholesteric

Cholesteric kua crystals zoo li cov nematic kua crystals, tab sis nyias muaj nyias cov qauv qub nrog nws cov maub los ntawm nws txoj kab ntsig. Nyob hauv ib lub dav hlau mus rau txoj kab xuab zeb, tsis muaj qhov sib txawv ntawm cov kua roj nematic kua. Cov tshuaj uas muaj feem xyuam ntawm cov cholesteric kua crystal theem muaj chiral chiral chaw (chiral) tsis muaj symmetry, thiab molecules nrog chiral radicals nyob rau hauv cov kua nematic kua muaj tau tshwm. Yog li no, cov roj pleev cov kua muaj roj tseem hu ua chiral nematic. Tsis tas li ntawd xwb, raws li lub pob ntseg ntawm chiral molecules, qhov kev taw qhia ntawm txoj kab ntawm txoj leeg spiral yog txiav txim siab. Vim li no, cov roj cholesteric kua muaj txheej txheem nyob rau hauv ib qho kev txiav txim raws li kev txiav txim thiab qhov axis muab phom, nrog rau qhov kev txiav txim siab kom tsis tiav. Lub sijhawm 1 - lub sijhawm ntev ntawm cov roj siv roj pleev ua kua roj yog hu ua cov kawm (degree), ib yam li nws muaj lub taub hau - cov yeeb yam hauv qab ntawm lub khob nematic ua kua, yog li lub sijhawm ntawd tsuas yog ib nrab ntawm cov kawm. Nws yog tsuas yog qhia los ntawm CLC lossis ChLC. N * kuj raug siv los nthuav qhia lub ntsiab lus ntawm cov kua roj cholesterol kua. Tseemceeb txhais tau tias yog chiral.

     

5.png   

Daim duab 4. suab ntawm cov kua roj cholesterol kua

- haus kua pleev ua kua

Cov kua siv ua kua ua kua muaj cov txheej txheem nyias nyias (lamella structure), uas tau muab faib ua SmA, SmB, SmC thiab SmD raws li txoj hauj lwm sib lawv liag thiab kev taw qhia ntawm tus tswj hauv tib txheej. Vim tias cov txheej txheem nyias, cov txheej txheem ze li ntawm crystalline ntxiv rau hauv kev txiav txim thiab muaj qhov kev txiav txim siab ntawm ntau tshaj 1 co. SmA txhais tau hais tias qhov chaw ntawm lub plhaub taum hauv cov txheej hauv plawv yog dawb thiab cov kev taw qhia ntawm tus maub los yog saib rau sab nyias. Txawm hais tias qhov chaw loj ntawm lub molecule yog dawb, qhov kev taw qhia ntawm tus maub los yog me ntsis inclined mus rau feem ntsug lub xeev ntawm nyias txheej.
Tshwj xeeb, SmC * (chiral SmC) siv nyob rau hauv cov zaub muaj cov yam ntxwv ntawm cov phenomelectric phenomenon (ferroelectricity). Raws li pom hauv daim duab 5, cov kua siv lead ua kua molecules yog tig mus rau hauv nyias txheej thiab muaj cov qauv ntawm kev hloov raws cov txheej txheem nyias. Cov kua siv lead ua kua molecules nyob rau hauv txhua txheej nyias nyias yog ntev mus rau cov kab ntev thiab muaj lub sij hawm dlhau spontaneous (spontaneous dipole caij) nyob rau hauv cov kev taw qhia mus tib seem rau nyias txheej, nrog cov kab mob ferroelectric.

 

6.png

SmA SmC


Daim duab 5. Tus sawv cev ntawm tus neeg haus luam yeeb txawv nrog kev taw qhia ntawm tus maub los ntawm nyias txheej.

7.png

Daim duab 6. txoj kev sib dhos ntawm molecular thiab lub caij nyoog kis dipole ferroelectric kua Crystal SmC *

(2) yam ntxwv ntawm LCD daim ntawv thov hauv cov khoom

Yog vim li cas vim li cas LCD yog nrov raws li ib lub monitor yog tias theem retardation tus nqi yuav tau kho yooj yim nrog qis voltage. Cov kua Crystal yog cov khoom siv anisotropic uas yog txawv ntawm cov maub los ntawm kev coj mus rau cov tswj thiab cov cuab yeej ntawm lub cev, vim nws txoj kev haum asymmetric molecular. Ntawm ntau lub cev nqaij daim tawv, qhov zoo tshaj plaws cawv rau ntawm lub LCD yog qhov muag anisotropy thiab dielectiric anisotropy. Qhov txawv ntawm qhov ntsuas tau qeeb (li 0.05-0.2) yog qhov kev xav thiab kev xav ntawm lub teeb thaum lub teeb kis tau los ntawm cov kua siv lead ua kua thiab muaj feem xyuam rau qhov kev xav thiab kev xav ntawm lub teeb. Lub dielectric anisotropy (li 3.0-8.0) yuav siv los tswj lub cev ntev ntawm cov kua siv lead ua kua molecules los ntawm cov hluav taws xob. Daim duab 8 qhia txog tus txheej txheem ntawm theem ncua raws li kev coj ua ntawm cov kua siv lead ua kua thiab qhov kev coj ntawm lub teeb. Tshaj li, lub dielectric dissimilarity ua rau cov kua siv lead ua kua molecules mus ua ke los yog rau cov hluav taws xob, thiab tswj cov kev taw qhia ntawm qhov ntev ntawm txoj kab ntawm cov kua siv lead ua kua los ntawm qhov hluav taws xob. Lub hauv paus ntsiab lus no yog qhia hauv daim duab 7.

8.png

Daim duab 7. txoj kev sib hloov ntawm cov kua siv lead ua kua molecules vim yog hluav taws xob


9.png

10.png

Daim duab 8. qhov sib txawv ntawm qhov ua rau ncua sij hawm theem (theem retardation) nrog kev coj ntawm cov kua siv lead ua kua.

2. kua siv lead ua kua

(1) tus maub los (tus thawj coj) thiab txiav txim siab parameter (yuam kev txiav txim siab).

Raws li tau hais los saum no, cov kua siv lead ua kua molecule yog ib qho bar nrog ntev txog 20 thiab txog 5 dav. Nws cov chaw loj yog zoo li cov lus tsa suab ntawm cov kua, thaum lub sij hawm ntev ntawm txoj kab xev tsiv tawm sai sai, tab sis cov ntsiab lus rau kev ua haujlwm tsis muaj teeb meem. Yog li ntawd, lub xeev cov kua muaj kua muaj peev xwm muab faib ua ob hom, namely cov kev coj ntawm qhov ntev ntawm txoj kab thiab qhov ntsuas ntawm thermal suab chaw nyob ntawm nws txoj kab. Qhia txog ob lub tswv yim no, lawv tswj hwm thiab txiav txim siab. Tus maub los tau muab txhais los ntawm ib chav tsev vector taw rau ib qho kev qhia tsis yeem. Tus maub los ntawm txoj haujlwm R feem ntau yog tuaj ntawm n (R). Qhov kev txwv parameter yog nruab nrab ntawm cov thermal suab, uas yog txhais raws li nram no.

11.png

Ntu 9. txhais ntawm cov tswj thiab lub theta thiab phi

12.png

Lub thauv theta, phi, raws li qhia hauv daim duab 9, sawv cev rau lub kaum sab xis ntawm lub qaij mus rau tus maub los. F (theta, phi) qhia tawm lub kaum sab laj ntawm qhov ntev ntawm txoj kab ntawm cov kua siv lead ua kua. Thaum ntev ntawm cov kua qaub ntawm cov kua qaub ua kua yog muab faib rau tag nrho cov khoom ntawm theta thiab phi, uas yog, nyob hauv isotropic theem (isotropic theem), f yuav ib qho thiab S = 0. Ntawm qhov tsis sib thooj, yog hais tias qhov ntev ntawm txoj kab ntawm cov kua siv lead ua kua molecules ua ke nrog N, nws yuav yog S = 1. Yog hais tias tus nqi ntawm cov khoom siv ua kua nematic ncav txog 0.3-08, lub siab dua qhov kub, qhov me me tus nqi.

(2) anisotropy (anisotropy)

Cov kua nplaum ua kua yog cov roj ntsha thiab cov dielectric anisotropy ntawm cov qauv thiab kev taw qhia ntawm kab txaij. Ua ntej, qhov kev sib tw ua ntsuas tau hais txog qhov kev hloov ntawm qhov hluav taws xob hauv hluav taws xob los ntawm qhov teeb meem ntawm lub teeb, uas ua rau lub sij hawm dipole, thiab ob lub teeb uas ua los ntawm nws qhov kev sib khoo overlaps nrog cov xwm txheej, uas qhia tau tias kev tshaj tawm ntawm lub teeb pom kev zoo ua rau qeeb ib ce tas li. Yog li ntawd, qhov zoo tshaj qhov molecule electronics huab yog reacted nyob rau hauv lub teb hluav taws xob ntawm qhov teeb meem lub teeb. Ntau dua tus nqi. Nyob rau hauv cov kua siv lead ua kua, cov teeb meem ntawm cov hluav taws xob hauv huab hauv qhov kev qhia ntawm qhov ntev thiab qhov kev qhia luv luv yog qhov sib txawv, yog li ua rau cov neeg tawg ua kom tsis muaj zog anisotropy. Raws li muaj nyob hauv daim duab. 10, tus thawj xibfwb ntawm tus txha caj qaum (lub ntsiab lus qis) yog txiav txim siab raws li kev taw qhia ntawm tus neeg saib xyuas n.
Uas yog hais tias, ib lub tsau ruaj khov yog tsim nyob rau hauv cov kev taw qhia mus rau ntawm tus neeg ua haujlwm, thiab ob lub ntsej muag rau daim ntawv no ua ib daim ntawv ruaj khov. Kev ntsuas ntawm kev txhawj xeeb los ntawm kev txhawj xeeb ntawm kev txhawj xeeb los ntawm kev txhim kho qhov Performance index los ntawm cov kev coj ua kom tsis muaj zog rau cov maub los yog tsis muaj, thaum lub ntsiab muag ntawm txoj hauv kev ntsug yog qhia tsis muaj, thiab cov lus nram qab no ntxiv E thiab o txhua tus sawv cev rau kev qhia tshwj xeeb thiab qhov kev ntsuas zoo tib yam. Cov kev qhia ntawm kev txheeb xyuas qhov muag tsis pom kev (anisotropy) (kev pom lub cev muaj zog) yog raws li nram no.

13..png

Ntawm qhov tod tes, lub peev xwm tseem yog ib lub cev tsis tu ncua uas qhia tias lub tshuab hluav taws xob molecular yog tsiv tawm ntawm sab nrauv sab nraum cov hluav taws xob, yog li qhov zoo dua qhov nqi ntawm lub zog ntawm cov huab cua hluav taws xob. Raws li nyob rau hauv qhov Performance index refractive, lub degree ntawm lub zog ntawm electron huab tau sib txawv ntawm qhov uas nyob rau ntawm qhov kev qhia ntev thiab axis luv luv, kom lub dielectric anisotropy tshwm sim nyob rau hauv cov kua siv lead ua kua. Lub zeem muag thiab cov kabmob ntawm tus maub los ntawm tus maub los yog qhia ntawm epsilon thiab epsilon. Dielectric anisotropy (dielectric anisotropy) muaj nyob hauv qab no.

14.png

15.png

Daim duab 10. txoj kev sib raug zoo ntawm cov maub los thiab cov spindle (thawj xib fwb)

(3) nruam nruab nrab txoj kev tshawb xav (Continuum Theory)

Feem ntau, txoj kev faib cov pa nematic ua kua tshuaj tiv thaiv muaj cov cuab yeej los ntawm kev ua nyob rau hauv ib qho kev qhia hauv chaw. Txawm li cas los xij, yog hais tias muaj kev txwv los yog lwm cov chaw hluav taws xob thiab cov chaw ntom ntom ntws tawm ntawm qhov teeb meem, qhov kev sib faib ntawm cov tswj yuav tsis zoo ib yam, thiab nyob rau hauv cov txheej txheem no, cov kua siv lead ua kua yuav ua rau cov deformation no. Txawm li cas los xij, qhov kev deev ntawm cov tswj lub cev tsis yog feem ntau tsis tsim nyob rau theem molecular (molecular scale), tiam sis yog ua nyob rau theem micron. Yog li, nws zoo dua los piav cov kua siv lead ua kua (Continuum) los piav txog nws cov deformation dua los piav txog txoj kev sib tshuam ntawm cov khoom ntawm tus kheej los ntawm kev piav txog lub cev deformation ntawm tus maub los. Qhov no zoo ib yam li ntawd kom sau tau lub zog thaum lub caij nplooj ntoos hlav thaum muab lub zog rau lub caij nplooj ntoos hlav, nws yog qhov zoo tshaj rau siv ib lub caij nplooj ntoos hlav tas mus rau sau cov nyiaj ntawm cov hlau thiab cov hlau atoms. Qhov no mus kom ze rau qhov sib npaug ntawm cov khoom siv sib luag ntawm cov khoom siv ua kua los ntawm txoj kev ua tus zauv. Nruam lub zeem muag yog ib qho qauv kev tshawb xav uas tuaj yeem yuav luag tag nrho cov qauv siv hluav taws xob ntawm cov khoom ua kua. Txawm li cas los xij, nws siv tsis tau los ntawm NMR thiab ESR, uas yog feem ntau ntawm cov kev tawm tswv yim ntawm cov molecules.

Yog tias muaj qee qhov kev mob (kev txwv, kev siv hluav taws xob, kev sib nqus field, thiab lwm yam.), Qhov kev deformation ntawm tus neeg saib xyuas n (R) tshwm sim. Tom qab ntawd, cov kua tshuaj ua kua molecules yuav tiv thaiv lawv lub cev tsis sib haum xeeb los ntawm txoj kev sib tshuam, thiab qhov loj ntawm qhov ywj pheej ntawm kev lag luam rau qhov deformation no yog proportional to qhov degree ntawm qhov kev hloov ntawm n (R) (xav txog, thaum lub caij nplooj ntoos hlav qhib, lub zog ntawm qhov kev tawm dag zog yuam yog qhov sib npaug ntawm Txoj Cai Hook tias qhov ntev yog rub tawm). Nyob rau ntawm qhov no, yog hais tias cov degree ntawm qhov chaw me me yog me, n (R) siv tau los sawv cev rau qhov sib txawv ntawm qhov chaw. Yog hais tias qhov loj ntawm qhov hloov me me tsis loj, ntau qhov sib txawv ntawm ntau yam tsawg dua 1 qhov sib txawv. Nqa mus rau hauv tus account cov kev xav thiab ntau lub cim, lub zog ntim dawb uas tsim los ntawm lub tsev ntim yog xam raws li lub cev deformation ntawm tus maub los.

16.png

Raws li pom hauv daim duab 11, qhov loj (splay), distortion (twist) thiab dabtsi yog khoov (khoov) deformation, K11, K22, thiab K33 siv raws li qhov sib piv ntawm qhov hu ua expansion, distortion thiab bending elastic constants feem. Tsis tas li, cov mis nyuj tov saum toj no hu ua Frank-Oseen dawb zog ceev. Qo yog ib qho tas li raws li chiral (chirality) ntawm kua siv lead ua kua molecules. Yog tias cov roj siv roj cholesteric, nws yuav muaj tus nqi tsawg tsawg, yog Qo> 0, qhov kev coj ntawm cov roj siv roj cholesteric yuav ua rau txoj hlua (right hand).

17.png

> >

Daim duab 11. hom kev hloov ntawm lub cev los ntawm cov kua xaim yas ua kua

Ntawm qhov tod tes, thaum lub teb hluav taws xob ntxiv rau cov kua siv lead ua kua ua kua, qhov faib ntawm cov huab cua hloov hluav taws xob, thiab tib lub sijhawm, nws ua raws li kev sib txuas lus electrostatic. Qhov ceev ntawm lub zog dawb rau kev sib raug zoo no yog xam raws li hauv qab no.

18.png

Yog li ntawd, thaum cov kua siv lead ua kua yog cuam tshuam vim hluav taws xob, tag nrho cov zog tsis pub muaj zog

19.png

Raws li txoj cai ntawm thermodynamics, cov kua siv lead ua kua muaj qhov faib rau kev txhim kho saum toj no f. Piv txwv li, yog tias ib qho hluav taws xob ntxiv ntxiv rau cov kua siv lead ua kua, yog tias tsuas yog cov kua siv kua roj (FE), suav tias cov maub los yuav tsum mus ua ke nrog fais fab; yog tias FD nkaus xwb, lub zog yuav tsum tau txo kom tsis muaj chaw pauv. Tab sis qhov tseeb, vim hais tias qhov sib tw ntawm ob hom zog yuav tsum tau qis dua, qhov chaw faib cov kua qia hlau siv tau yog txiav txim siab ntawm qhov kev hloov pauv thiab qhov sib luag ntawm qhov tsim nyog tau txais kev ua haujlwm.

20.png

21.png

Daim duab 12. thaum siv lub tshuab fais fab, lub zog (torque) txuas nrog cov kua siv lead ua kua.

Kev daws ntawm qhov sib npaug sib npaug no yuav txiav txim siab faib rau cov khoom siv dej ua kua. Nws zoo li me ntsis nyuab, tab sis tom qab ob peb yam yooj yim, txoj kev daws teeb meem yog nyob rau hauv cov ntawv qhia appendix. Cov mis nyuj uas tau hais los saum no yog hais txog cov qauv formula. Yuav kom paub qhov kev coj cwj pwm ntawm tus LCD controller, peb yuav tsum tau ua qee qhov kev hloov me me. Yog tias qhov chaw pw kom zoo tshaj, feem ntau cov kinetics ntawm cov kua Crystal yuav ua tau raws li cov nram no.

22.png

Ntawm lawv, t qhia lub sijhawm, thiab gamma 1 ua tus cev viscosity. Tus me dua qhov kev hloov viscosity, ceev cov sij hawm hloov ntawm tus LCD controller.

(4) qhov kub nyob ntawm lub cev tsis tu ncua

Cov khoom siv kho qhov muag ntawm cov kua siv lead ua kua yog txiav txim siab los ntawm kev faib khoom thiab kev ntsuas qis ntawm cov maub los, thiab kev faib rau cov maub los nyob ntawm sab nrauv hluav taws xob, kev limiting, qhov muaj peev txheej thiab qhov hloov ntawm lub cev. Nyob rau hauv no txoj kev, peb yuav paub qhov tseem ceeb ntawm refractive index, permittivity thiab elastic constants ntawm lub kua crystal nws tus kheej nyob rau hauv tus txheej txheem ntawm kev nkag siab LCD. Tsis tas li ntawd, qhov tseem ceeb nyob rau hauv cov lus teb ntawm cov kua kua muaj zog yog qhov ua daim phiaj viscosity.

Nws tau tshaj tawm hais tias qhov kev txiav txim nram qab no S cuam tshuam rau dielectric anisotropy, refractive index anisotropy thiab elastic constants.

23.png

Qhov kev txwv parameter S txo thaum rhuab, yog li nws muaj peev xwm yuav kwv yees tias cov qauv siv hluav taws xob ntawm cov kua siv lead ua sib txawv rau qhov kub thiab txias. Tsis tas li ntawd, txawm hais tias tsis yog nyob hauv cov kua muaj kuab, lub Kwj Qis K33 / K11 tseem muaj feem xyuam rau qhov ntev ntawm qhov ntev ntawm txoj kab thiab luv luv ntawm cov kua siv lead ua kua, uas yog proportional to L / W.

3. kua siv lead ua kua

(1) kua siv ua kua ua kom sib haum (sib law)

Thaum cov kua siv lead ua kua tso rau hauv lub raj mis (lub raj mis), nws yog xim dawb vim tsis muaj hluav taws xob hauv av. Nws yuav ua tsis muaj xim thiab pob tshab thaum muab tso rau ntawm cov saum npoo ob iav daim hlau, vim hais tias lub LCD tswj yog nyob rau hauv ib txoj kev qhia. Rau qhov kawg no, qhov kev kho mob saum npoo yog qhov tseem ceeb heev. Nyob rau hauv txoj kev no, xws li hauv daim duab 14, cov kua siv lead ua kua tshuaj yuav muab kho rau ib txoj kab sib ntsug ntsug (homeotropic) rau saum npoo av, ib txoj kab sib sib koom ua ke (hom phom sij) npaj mus rau ntawm qhov chaw, ib hom kab tsho, uas yog tsa hauv tej lub kaum ntse ntse, thiab lwm yam. Yog tias koj xav tsa ib txoj kab sib ntsug ntsug, koj tuaj yeem thov lub ncov qaumteb qabteb zoo li lecithin mus rau iav substrate. Kab rov tav los sis lub kaum sab xis qis tsis tiav los ntawm lub nplaum deg ntawm iav substrate thiab so tawm ntawm daim ntaub. Qhov no hu ua rubbing. Feem ntau, kev sib txuas ntawm lub cawv yog tias qhov kev nthuav dav yog tsim kom muaj cov khoom siv coj los ua kua (cov qee cov dej uas siv los ntawm kev txuas ntxiv).

24.png

Daim duab 13. sib tawg ntawm lub teeb nyob rau hauv cov kua nplaum uas muaj kua txig thiab txwv cov txwv tsis pub sib khi

25.png

Daim duab 14. hom kua siv ua kua


26.png

Daim duab 15. ua lub hauv paus (pretilt angle) theta

Nyob rau lub sij hawm no, tag nrho cov kua qaub tsim kua hlau tsis sib haum xeeb rau cov substrate, tab sis qaij rau lub substrate ntawm lub kaum ntse ntse. Lub kaum sab xis no yog hu ua lub hauv ntej.

(2) ECB (hom tshuaj tswj fwm ib leeg)

Nrog rau qhov tshwm sim no, cov ntaub ntawv yuav muab kho los ntawm lub teeb hloov ntawm qhov voltage. Raws li hauv daim duab 16, ib lub teeb tawm ntawm lub ncov yog tau los ntawm lub ncov (Polarizer), thiab lub xeev qhov ci ntawm lub teeb sib txawv nrog lub txiv neeb ntawm cov kua siv ua kua thaum lub teeb ntsuab tuaj ntawm cov kua siv kua qaub. Thaum lub teeb ci no dhau los ntawm tus neeg soj ntsuam (tus txheeb xyuas), qhov kev siv ntawm lub teeb ntawm tus neeg soj ntsuam kuj tseem yuav hloov nrog lub sij hawm ntawm theem ncua (theem retardation) uas ua los ntawm cov khoom siv ntawm cov kua siv ua kua. Ntawm lub sij hawm no, qhov sib tw ntawm cov kua siv lead ua kua ua rau lub siab ntawm cov kua qaub ntawm cov kua qaub ua kua (refractory index) ellipsoid thiab lub teeb pom kev ntawm lub teeb yog tias cov kua siv lead ua tau muab tso rau ntawm ob iav daim hlau dhau los ntawm txoj kab nruab ntug (qhov no hu ua kua siv lead ua kua (cell)), xws li cov kua tshuaj siv ua kua molecules nyob hauv daim duab. 15 (a). Ntawm no voltage, lub dielectric anisotropy ntawm kua siv lead ua molecules.

Cov kev taw qhia ntawm qhov hluav taws xob yog tib seem, yog li qhov ncua sij hawm qeeb vim yog kua kua qia cell yog me dua (saib Daim Duab 4). Yog li, kho qhov voltage tuaj yeem hloov qhov kev hloov ntawm lub teeb.

27.png

Daim duab 15. kev hloov ntawm cov neeg tswj hauv LCD hauv ECB hom mob hloov qhov hloov


28.png

Daim duab 16. cov cuab yeej sim rau kev hloov cov teeb ntawm lub teeb raws li qhov hloov ntawm cov kua siv lead ua kua tshuaj