| LCD, or liquid crystal display, televisions use a unique | | | | S-PVA LCD panel are able to deliver a very good |
| form of technology to produce their display, and | | | | viewing angle at up to 140 degrees, and they also can |
| although early models had a number of technological | | | | provide a good contract ratio for viewing both light |
| issues, those issues have largely been overcome, and | | | | scenes and dark ones. The downside of the PVA and |
| these days there are excellent quality LCD TVs | | | | S-PVA technology is that they often have problems |
| available from virtually every manufacturer of | | | | with "ghosting" when the scene moves between |
| electronics in the world. | | | | different shades of dark. |
| The earliest models of LCD televisions often had | | | | Traditional CRT televisions to not have this problem |
| problems with "ghosting", especially when displaying | | | | with "ghosting" since the phosphor contained in the |
| fast action or fast moving imaging, and these early | | | | CRT is charged by the strike of a beam of electrons, |
| televisions were best viewed straight on or from a | | | | and it emits most of the light in a fast period of time, |
| slight angle. These early problems have been | | | | generally less than 1 millisecond, compared to a refresh |
| overcome by advances in technology, and LCD and | | | | period of about 20 milliseconds. For an LCD TV, each |
| plasma TVs are making serious inroads on the | | | | pixel emits light of a set intensity for a period of about |
| traditional CRT (cathode ray tube) television market. | | | | 20 milliseconds, in addition to the time it takes to switch |
| The prices of LCD televisions have come down quite | | | | to the next state, which is typically between 12 and 25 |
| a bit as well, even as the technology they use has | | | | milliseconds. |
| continued to improve. These days the least expensive, | | | | This response time, also known as the response time, |
| small screen LCD TVs can often be purchased for a | | | | can be shortened by the design of the panel, and by |
| couple hundred dollars, while the largest displays sell for | | | | using overdriving technology, but the response time |
| several thousand dollars. There are even larger LCD | | | | can only be cut down to the length of the refresh |
| displays on the market, as large as 65" and even | | | | period. |
| more, that may sell for $10,000 or more. If price is no | | | | Getting the response time equal to the refresh period |
| object it is possible to find an LCD TV for virtually any | | | | is generally sufficient for watching films and television |
| taste. | | | | programs, but for videos shot at 50 or 60 frames a |
| The advent of these large screen LCD TVs is another | | | | second there can still be some ghosting issues with |
| indication of how much the technology has improved in | | | | some LCD TVs. |
| a short period of time. When LCD technology was first | | | | Fortunately, there are a number of emerging |
| being developed, the conventional wisdom was that it | | | | technologies within the world of the LCD TV, and |
| would be suitable only for small size televisions, and | | | | these technologies promise to eliminate some of the |
| that the LCD technology would not be able to | | | | ghosting and other issues that have been encountered |
| compete with plasma screens for larger sets. These | | | | by owners of these TVs. The first solution on the |
| days, however, ever larger LCD TVs are being | | | | horizon is to make the backlight of the LCD panel fire |
| developed and introduced, by the likes of Sony, Sharp, | | | | during a period of time that is shorter than the refresh |
| Samsung, Phillips and others. | | | | period. The goal is to make this period of time as short |
| The modern LCD TV is good for much more than | | | | as possible, and to time it for when the pixel has |
| watching TV, and the best sets on the market come | | | | already settled to its intended level of brightness. This |
| with a multisystem tuner, which allows the machine to | | | | technique, however, also introduces the problem of |
| display not only the NTSC format common throughout | | | | flicker that is so familiar to users of CRT computer |
| North America, but the PAL and SECAM signals that | | | | monitors. This flicker problem occurs because the |
| are common in other parts of the world. In addition, | | | | human eye is able to see flicker at the typical 50 or |
| many LCD TVs include a step down and step up | | | | 60Hz refresh rates used in this technology. |
| transformer which can automatically use either 110 or | | | | Another emerging response to the problem is to |
| 250 volt AC current, as well as universal grounded | | | | double the refresh rate of the LCD TV, and then to |
| adapter plugs for added versatility. | | | | reconstruct the intermediate frames using a variety of |
| In addition, virtually all modern LCD TVs on the market | | | | motion compensation techniques. This second method |
| today are capable of displaying the latest HDTV (high | | | | is being extensively studied on the new high end |
| definition television) and DTV (digital television) signals, | | | | televisions currently being designed in Europe. |
| and most can also be used as a computer monitor, by | | | | No matter what type of LCD TV technology you |
| connecting them to a VGA or DVI signal. Those TV | | | | decide to buy, however, it is important to shop around |
| shoppers planning to use their new LCD TV as a | | | | for the best possible price. These days even discount |
| monitor should be cautious, however, since the quality | | | | retailers often sell some very good LCD TVs, and of |
| of the resolution can vary widely between brands and | | | | course many electronics stores are virtually replacing |
| models. | | | | their existing stock of CRT TVs with the newest in |
| LCD TV Considerations | | | | LCD and plasma screen technology. As with any |
| Those in the market for an LCD TV to replace a | | | | major purchase, it is vital to shop around for the best |
| traditional CRT TV should be aware of the | | | | deal, and to read the reviews of each model carefully. |
| differences in the technology, and what those | | | | As with any piece of electronic equipment, the quality |
| differences mean in terms of viewing pleasure and | | | | of an LCD TV can vary quite widely from model to |
| lasting value. LCD televisions based on the PVA and | | | | model and brand to brand. |