Displayer Technology
The mainstream displayer technologies are as followed:
-LCD
LCD technology is based on the properties of polarized light. Two thin, polarized panels sandwich a thin liquid-crystal gel that is divided into individual pixels. An X/Y grid of wires allows each pixel in the array to be activated individually. When an LCD pixel darkens, it polarizes at 90 degrees to the sandwiching polarizing screens. This cross-polarizing blocks light from passing through the LCD screen where that pixel has darkened. The pixel darkens in proportion to the voltage applied to it: For a bright detail, a low voltage is applied to the pixel; for a dark shadow area, a higher voltage is applied. LCDs are not completely opaque to light, however, some light will always penetrate even the blackest LCD pixels.
Life span of LCD screens, the number of viewing hours a television provides before dimming to half brightness, is one of the biggest advantages LCD has over plasma. Though the numbers vary among the different brands, plasma TVs offer 30,000 to 60,000 hours to half life, while LCD TVs last for up to 60,000 and possibly longer if bulb replacement is an option.
- OLED
Organic light-emitting diode (OLED), also Light Emitting Polymer (LEP) and Organic Electro-Luminescence (OEL), is any light-emitting diode (LED) whose emissive electroluminescent layer is composed of a film of organic compounds. The layer usually contains a polymer substance that allows suitable organic compounds to be deposited. They are deposited in rows and columns onto a flat carrier by a simple "printing" process. The resulting matrix of pixels can emit light of different colors.
Such systems can be used in television screens, computer displays, portable system screens, advertising, information and indication. OLEDs typically emit less light per area than inorganic solid-state based LEDs which are usually designed for use as point-light sources.
A significant benefit of OLED displays over traditional liquid crystal displays (LCDs) is that OLEDs do not require a backlight to function. Thus they draw far less power and, when powered from a battery, can operate longer on the same charge. Because there is no need to distribute the backlight, an OLED display can also be much thinner than an LCD panel. OLED-based display devices also can be more effectively manufactured than LCDs and plasma displays. But degradation of OLED materials has limited their use.
In summary, OLED displays have:
- High brightness and contrast
- Ultra-wide viewing angle
- No backlight required
- Thin, compact form factor
- Fast response time
- Low power consumption
-Plasma
Plasma screens are basically a network of red, green and blue phosphors (each triad makes up a single pixel) mounted between two thin layers of glass. Plasma screens use a small electric pulse for each pixel to excite the rare natural gases argon, neon and xenon used to produce the color information and light. As electrons excite the phosphors, oxygen atoms dissipate and create plasma, emitting UV light. These rare gases actually have a life and fade over time.
As all the phosphor-excited pixels react at the same time, there is never any flicker apparent to the viewer. There's also no backlight and no projection of any kind, so the light-emitting phosphors, result in a bright display with a penchant for rich color and a wide viewing angle.
Plasma Advantages:
- Excellent (real) contrast ratios and black levels
- Excellent color reproduction
- Excellent life expectancy
- Excellent viewing angle with no real loss of color or contrast
Plasma Disadvantages
- Fairly heavy
- Soon destined to be thicker than LCDs by a large margin, barring some practical technical advances
- Susceptible to screen burn-in (new models compensate with various screen-saving methods)
- Lower real peak brightness
- Uses a lot of power compared to LCD
Source:
http://www.dtvcity.com/lcdtv/lcdtvresources.html
http://www.siliconchip.com.au/cms/A_30650/article.html
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