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| Liquid Crystal Display (LCD) plays a main role in flat panel display (FPD) which is widely used in mobile device, especially mobile phone, notebook, PDA, carnavigation system, etc. Among LCDs, TFT (Thin film transistor) addressed LCD is quickly increasing its significance in modern color FPD for its high quality image. The market for TFT-LCD is now growing much faster than expected and impacting new application fields, as well as conventional fields. |
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 Passive Matrix LCD (PMLCD) |
| Active Matrix LCD (AMLCD) |
 MIM-LCD |
| TFD-LCD |
| TFT-LCD |
 a-Si TFT-LCD |
| Poly-Si TFT-LCD |
 High Temperature poly-si TFT-LCD |
Low Temperature poly-si TFT-LCD
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| Display Mode |
Resolution |
Numbers of Pixels |
Description |
| QVGA |
320×240 |
230,400 |
Quarter VGA |
| EGA |
640×400 |
768,000 |
Enhanced Graphics Array |
| VGA |
640×480 |
921,600 |
Video Graphics Array |
| Wide VGA |
800×480 |
1,152,000 |
Wide VGA |
| Svga |
800×600 |
1,440,000 |
Super VGA |
| Wide SVGA |
1024×600 |
1,843,200 |
Wide SVGA |
| XGA |
1024×768 |
2,359,296 |
Extended Graphics Array |
| SXGA |
1280×1024 |
3,923160 |
Super XGA |
| SXGA+ |
1400×1050 |
4,410,000 |
Super XGA+ |
| UXGA |
1600×1200 |
5,760,000 |
Ultra XGA |
| Wide UXGA |
1920×1200 |
6,912,000 |
Wide UXGA |
| QXGA |
2048×1536 |
9,437,184 |
Quad XGA |
| QSXGA |
2560×2048 |
15,728,640 |
Quad Super XGA |
| QUXGA |
3200×2400 |
23,040,000 |
Quad Ultra XGA |
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| The complete TFT-LCD module, shown in Fig.1 and Fig.2, contains two glass substrates, a TFT substrate and a color filter substrate, within them liquid crystal is encapsulated. Two polarizers are pasted at the top and bottom of two glasses, respectively. The light source, which can be the fluorescent lamps or LEDs, are positioned directly beneath the rear polarizer. |
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| Fig. 1 The structure of TFT-LCD |
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| Fig.2 The vertical structure of a color TFT-LCD |
| TFT substrate |
| In AMLCD, the TFTs are used as switching devices. The TFT substrate
contains the TFTs, storage capacitors, pixel electrodes, and interconnect
wiring. The LSIs are also bonded on the TFT substrate to drive the TFT panel.
Figure 3 shows the TFT and the pixel structure, the equivalent circuits of
single-TFT and whole substrate are shown in Fig. 4 and Fig. 5.
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| Fig. 4 The TFT equivalent circuit |
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| Fig. 5 The equivalent circuit of TFT-array substrate |
| Color Filter |
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| Fig.6 The structure of color LCD |
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| Fig. 7 Types of color filter |
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| Fig. 8 The structure of color filter |
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| Fig. 9 Color filter layout |
| Polarizer |
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| Fig. 10 The theory of polarizer |
| Liquid crystal |
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| Fig. 11 Types of LC |
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| Fig. 12 Twist-nematic LC |
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| Fig. 13 Super twist-nematic LC |
| Backlight |
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| Fig.10 Types of backlight |
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| Fig. 11 The structure of backlight |
