Q: What are the advantages of TFT LCD compared with CRT?
A:In a CRT monitor, a gun shoots electrons and general light by colliding polarized electrons on fluorescent glass. Therefore, CRT monitors basically operate with an analogue RGB signal. A TFT LCD monitor is a device that displays an input image by operating a liquid crystal panel. The TFT has a fundamentally different structure than a CRT: Each cell has an active matrix structure and independent active elements. A TFT LCD has two glass panels and the space between them is filled in with liquid crystal. When each cell is connected with electrodes and impressed with voltage, the molecular structure of the liquid crystal is altered and controls the amount of inlet lighting to display images. A TFT LCD has several advantages over a CRT, since it can be very thin and no flickering occurs because it does not use the scanning method.
Q: Why is a vertical frequency of 60Hz optimal for an LCD monitor?
A:Unlike a CRT monitor, the TFT LCD panel has a fixed resolution. For example, an XGA monitor has 1024x3 (R, G, B) x 768 pixels and a higher resolution may not be available without additional software processing. The panel is designed to optimise the display for a 65MHz dot clock, one of the standards for XGA displays. Since the vertical/horizontal frequency for this dot clock is 60Hz/48kHz, the optimum frequency for this monitor is 60Hz.
Q: What kind of
A:The TFT LCD panel is an element that controls/displays the inlet of a backlight using the dual refraction of a liquid crystal. Using the property that the projection of inlet light refracts toward the major axis of the liquid element, it controls the direction of inlet light and displays it. Since the refraction ratio of inlet light on liquid crystal varies with the inlet angle of the light, the viewing angle of a TFT is much narrower than that of a CRT. Usually, the viewing angle refers to the point where the contrast ratio is 10. Many ways to widen the viewing angle are currently being developed and the most common approach is to use a wide viewing angle film, which widens the viewing angle by varying the refraction ratio. IPS (In Plane Switching) or MVA (Multi Vertical Aligned) is also used to give a wider viewing angle.
Q: Why is there no flicker on an LCD Monitor?
A:Technically speaking, LCDs do flicker, but the cause of the phenomenon is different from that of CRT monitor — and it has no impact of the ease of viewing. Flickering in an LCD monitor relates to usually undetectable luminance caused by the difference between positive and negative voltage. On the other hand, CRT flickering that can irritate the human eye occurs when the on/off action of the fluorescent object becomes visible. Since the reaction speed of liquid crystal in an LCD panel is much slower, this troublesome form of flickering is not present in an LCD display.
Q: Why is an LCD monitor virtually free of Electro Magnetic Interference?
A:Unlike a CRT, an LCD monitor does not have key parts that generate Electro Magnetic Interference, especially magnetic fields. Also, since an LCD display utilizes relatively low power, its power supply is extremely quiet.
DV300/DV301B 30" Multimedia Information Display
11.Technical Specifications
LCD PANEL |
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• Type |
| TFT LCD |
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• Screen size |
| 29.5 inch |
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• Pixel Pitch |
| 0.5025 x 0.1675 mm x RGB | ||
• LCD Panel type |
| 1280 x 768 pixels |
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| R.G.B. vertical stripe | ||
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| Hard coating surface, | ||
• Effective viewing area |
| (H) 643.2 x (V) 385.92mm | ||
• Display Colours |
| 8 bits interface (16.7M colours) | ||
PC SCANNING |
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• Vertical refresh rate |
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• Horizontal frequency |
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PC VIDEO |
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• Video dot rate |
| < 80 MHz |
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• Input impedance |
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- Video |
| 75 ohm |
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- Sync |
| 2.2K ohm |
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• Input signal levels |
| 0.7 Vpp |
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• Sync input signal |
| Separate sync |
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• Sync polarities |
| Positive and negative | ||
• Input Frequency |
| WXGA | Hsync | 48 kHz, Vsync 60 Hz (N.I.) |
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| SVGA | Hsync | 38 kHz, Vsync 60 Hz (N.I.) |
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| VGA | Hsync | 31 kHz, Vsync 60 Hz (N.I.) |
• Video interface |
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| components video (others) | ||
AUDIO |
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• Input level for PC/SVHS/SCART |
| 500 mV nominal |
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• Loudspeaker |
| 5W Stereo Audio (2.5W/channel RMS x2, 200Hz~10kHz, | ||
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| 4 ohm, 10% THD) |
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57 | 58 |
