LCD

200600226

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................................................................................... 5

1.1 ; ...................................................................................... 5

1.2 .............................................................. 6

1.3 ............................................................................................ 7

1.3.1 (nematic) ...................................................................................... 7

1.3.2 (smectic) ......................................................................................... 8

1.3.3 (cholesteric) .............................................................................. 9

1.3.4 (columnar) ................................................................................. 11

1.4 ...................................................................... 11

1.5 .................................................... 13

1.5.1 ........................................................... 13

1.5.2 ......................................................................................... 13

1.5.3 Freedericksz ........................................................................................ 14

1.6 ....................................................................................................... 15

1.7 .................................................................. 16

1.8 ........................................................................................... 18

1.8.1 ................................................................................. 18

1.8.2 ............................................................................... 18

1.9 ............................................................... 19

................................................... 21

2.1 (LCD) ...................................................... 21

2.2 ................................................ 23

2.3 LCD ............................................................. 24

2.4 ..................................................................................................... 25

2.5 .................................................................................................................... 25

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2.6 ................................................................................... 25

2.7 ........................................................................................................... 26

2.8 .......................................................................................... 26

2.8.1 (Twisted Nematics TN) ................................. 28

2.8.2 (Super Twisted Nematics STN) ............... 30

2.9 .............................................................................................. 33

2.9.1 (Thin Film Transistor TFT) .................................... 34

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1888 , Friedrich Reinitzer . , Reinitzer . , , . , Reinitzer - . . , .

1.1 ;

. , , . (mesogens) . , . , . . .

. .

6

. , . , (S). :

. . , . . 0.3 0.9, , . .

. . .

1.2

:

7

. . . . , . . , , .

1.3

() () . , .

1.3.1 (nematic)

.

, . , . , , . (chiral nematic). .

8

1.3.2 (smectic)

. , , . , . , .

. , . - , , . , - , . - - , .

- -

9

- -

, - *. - , . . , - , .

-

, . .

1.3.3 (cholesteric)

( ) (mesogens) . . .

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. . . , p, 360, . , . , . , , . . , . , , , , "". , . .

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1.3.4 (columnar)

. .

. .

1.4

(Differential Scanning Calorimetry DSC) . . , DSC 8 OCB (octyloxy cyanobyphenyl) 1 C/min . (a) . , . ( ). (-) 55C - 67C (NI) 80C. , , , . - - . , .

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(a) : DSC

(b) , - , . - DSC .

(b) : DSC

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1.5

, . . , . , .

1.5.1

. . . , . , .

, . , . , . . , . , .

1.5.2

, . , ,

14

. , ( ) , . .

1.5.3 Freedericksz

. , :

, , . , . . Freedericksz . Freedericksz , ( ) .

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1.6

, . , XZ . . , .

. , , , . . , . , . , 90, . . .

. , YZ

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XY. , , , 45 . .

, 180 , 45 .

90 ( ), . , . .

. .

1.7

. ( ).

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( ) . , .

, , , , ( ) ( ). , . , .

.

, n, . ,

, , ne = c/V no = c/V ,

, n = ne no.

, n , . ne >no , . , no 1.5 n.

, n, 0,05 0,5. , .

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. , , . L , nL

L (ne no) = Ln. (

) 2 Ln/v v .

1.8

. .

1.8.1

. , . ( ) (planar) , . , , (homeotropic) , .

1.8.2

disclination.

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. disclination.

. .

1.9

: (thermotropic) (lyotropic) . , . , . , . : (enantiotropic)

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, , (monotropic) , . , . , . (micellar). , (lyophilic) (solvent-repelling) . (micellar) . , . . . , . : . . . . (low molar mass LMM) , 5CB :

. , , . . -(CH=N)-, -N=N-, -(CH=CH)n-, -CH=N-N=CH-, . . , . .

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2.1 (LCD)

LCD, (CRT). . , . (), ( ). , , , , . . 90, LCD , , , CRT. 19 , LCD RCA's David Sarnoff Research Center George Heilmeier 1968,

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1970 Nunzio Luce, Louis Zanom, George Graham, Joel Goldmacher RCA Optel Corporation, LCD , . 70, LCD, Seiko-Epson LCD , Casio Sharp . 1971, M. Schadt, W. Helfrich James Fergason (twisted nematic TN) , , LCDs. , - (direct view) , . (super twisted nematic STN) T. Scheff J. Nehring, . STN . - . , . Lechner , Marlowe Nester pixel . P.Brody (thin film transistor TFT) CdSe 1973 pixel. CdSe TFT , . , TFT LCD. , Si-TFT , Si-TFT. LCD.

Switching devices Mobility* (cm2/Vsec)

Highest process temperature

Major applications

a-Si TFT 0.3-1 ~ 3000C (glass) Laptop screen, PC monitor, LCD TV

High-T poly-Si TFT 100-300 ~ 10000C (quartz) Projection light valves, viewfinders

Low-T poly-Si TFT 10-200 ~ 5000C (glass) PDA and laptop screens, Projection light valves, viewfinders

Crystalline Si MOSFET 400 ~ 11000C (C-Si) Projection light valves, viewfinders

Thin film diode < 3000C (glass) Handheld devices' screen

Table. 1 different types of switching devices for active matrix LCD.

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LCD, . In-Plane-Switching (IPS) , Samsung Patterned Vertical Alignment (PVA) , . , Optical Compensated Bend (OCB), Multi-domain Vertical Alignment . (direct-view), 70. (LCoS) , TV LCD - . , , LCD , , .

2.2

, . . . , . , LCD. . , (twisted nematic) . , . LCD . LCD :

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(A) , . (B) , (C) () . LCD. (D). (E) (F), . . , LCD . , . .

2.3 LCD

. LCD , , . LCD . . LED , . LCD . , LED:

, , .

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(reflective) , . . LCD (transmissive) . . , . LCD . , . .

2.4

pixel. as Ton Toff , / 90% /. Toff , , , . , . , .

2.5

. pixel , . , . LCD . , . . .

2.6

, , . LCD , .

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, , , , ..

2.7

. . . 7 , , . .

2.8

LCD pixel . . , . , . pixel, . pixel, pixel. pixel ( ) , , . , pixel .

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. . , pixel . . , pixel , pixel . . , . , , pixel 1/ . , . , pixel . . 3x3 :

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pixel . (strobe signal), . pixel , . pixel RMS . pixel (strobe signals) .

2.8.1 (Twisted Nematics TN)

. . 90 , .

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, . . , . , 6 8 , 90 . , , . , . . . , .

, on off . , ,

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pixel, . , . . . , . :

pixel pixels, ( ghosting). , 150 milliseconds. . , ( ). , . UON/UOFF pixel VGA . , - . - 90.

2.8.2 (Super Twisted Nematics STN)

STN . N OFF

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. , . 80 STN . , 270, 90 TN. - :

, 270. :

- , . STN 210. . STN STN . STN, . STN 500 .

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, . TNLCs, 200 milliseconds 60 milliseconds. , STN . STN LCDs - , ON OFF . STN , . STN LCD. LCD, , , . , RGB, . , . -pixel . -pixel, - , pixel . -pixel -pixel. pixel . STN 320 x 240 pixel 960 x 240 pixels. TFT, , , . , STN . . , , . STN , , . STN "double super twisted nematic LCD" DSTN LCD. DSTN STN . LCD, , . DSTN LCD STN, . . DSTN LCD ,

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. -30C 80C. -40C 90C. , . FSTN (Film Compensated Super Twisted Nematic) . / , . , , , , FSTN , GPS, , PDAs.

2.9

, . :

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2.9.1 (Thin Film Transistor TFT)

TFT. , TFT active matrix, . , , . , pixel , . (TFT) , pixel (refresh) . TFT: (amorphous silicon a-Si), (polycrystalline silicon p-Si), (single crystal silicon x-Si). TFT (a-Si). TFT , , . - (area/voltage seconds), pixel. a-Si TFT , 14. TFT, (RGB) pixel. pixels, -TFT LCDs. 25ms, 200:1 400:1, 200 250cd/m2(candela per square meter). TFT LCD, , pixel CRTs 10 DSTN. VGA 921,000 (640 x 480 x 3), 1024 x 768 2,359,296 . , wafer wafer . TFT. TFT pixels . LCD pixel. pixel, pixel , pixel, . , , -pixel . pixel . pixel laser. , . pixel LCD -

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pixel LCD . pixels. , 1024 x 768, 2,359,296 (1024 x 768 x 3) pixel. 20 pixel, pixel (20/2,359,296) x 100 = 0.0008%. TFT :

TFT LCD , STN DSTN, , , . pixel. , laptop, , HD FullHD, , healthcare equipment, TFT .

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