Defining TV Jargon
There's no other major item most of us own that is as confusing, unpredictable and unreliable as our personal computers. Everybody has questions about them, and we aim to help. This week's mailbox is devoted to answering the many questions I get about today's confusing television terminology.
If you have a question, send it to me at
mossberg@wsj.com, and I may select it to be answered here in Mossberg's Mailbox.
Because of the volume of e-mail I receive, I can't routinely answer individual questions by e-mail, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.
Q. Can you give a very brief, basic explanation of the differences between the main kinds of flat-screen TVs -- Plasma, LCD, and DLP? I get confused every time I walk into Circuit City.
A. Einstein would get confused in the TV aisles at Circuit City, so don't feel bad.
LCD flat-panel televisions use the same technology found in laptop screens and flat-panel desktop computer monitors. The vivid picture is produced using a costly, special glass panel with transistors attached to it. But they are expensive, especially in larger sizes above 40 inches. Some models can also be tough to see from side angles. Prices are expected to drop next year.
Plasma televisions produce rich, vivid pictures by using a gas trapped between sheets of glass. They are less expensive than LCDs, especially in sizes over 40 inches. Like LCDs, they are skinny. Until recently, many plasmas suffered from relatively short life cycles; the risk of burn-in of fixed images left on the screen a long time; and a failure to work at higher altitudes. But these problems have been mitigated, at least in better models.
DLP televisions are generally less expensive than either LCDs or Plasmas, though usually substantially thicker. They are actually a form of rear-projection TV -- the slimmed-down, digital successor to the old, room-filling rear projection models. They produce TV pictures in a special chip at the rear of the set. This chip, made by Texas Instruments , contains many thousands of tiny mirrors that project the picture onto the back of the screen, which is much simpler and cheaper than LCD or Plasma screens. The result is a very attractive picture, at large sizes, but at a lower price. The tradeoff is that these sets still aren't nearly as skinny as LCDs or Plasmas.
Watch out for some confusing terminology. Some makers, like Sony, sell "LCD" sets whose screens really aren't LCD panels. Instead, these sets are really rear-projection models that use tiny LCD monitors at the rear of the set, instead of a DLP chip. Other sets are advertised as "flat screen," even though they are just old-fashioned TVs with flat glass in front, instead of the usual curved glass.
Finally, don't confuse flat-panel or big-screen TVs with High Definition. Many flat-panel, big-screen TVs sold today aren't capable of displaying TV programming in high definition. By the same token, you can buy a fat, traditional-style TV that's equipped to receive HD. So, if you want both a big screen, flat-panel set, and high definition, you'll have to check carefully to make sure any set you buy has HD capability. And, you have to subscribe to a cable or satellite service that offers HD programming, via a special set-top box; or you have to use a rooftop antenna to capture over-the-air HD signals.
几种主要平板电视的区别
在我们大多数人拥有的大件电器中，再没有什么比个人电脑更令人费解、更变幻莫测的了。每个人或许都有些关于电脑的问题，而《莫博士信箱》将为您提供帮助。
本周我将回答读者有关平板电视的问题，介绍有关离子电视、液晶电视和数码光显背投电视的一些基本知识。
问：你能给我简要介绍一下等离子电视、液晶电视(LCD)、数码光显背投电视(DLP)这几种主要的平板电视之间的差别吗？我总是把它们混为一谈。
答：即使是爱因斯坦可能也会弄混的，所以这没有什么。
液晶电视使用的是和笔记本电脑及台式电脑平板显示器相同的显示技术。其生动的画面是由一个造价不菲的特殊玻璃嵌板以及上面的晶体管生成的。不过这种电视价格昂贵，特别是超过40英寸的大尺寸液晶电视。一些液晶电视在从侧面观看时，画面也不是十分清楚。预计明年液晶电视的价格将会有所下降。
等离子电视是利用两块玻璃基板之间的气体来显现出色彩丰富而生动的画面。这种电视较液晶电视稍便宜，特别是40英寸以上的大电视。和液晶电视一样，等离子电视厚度也很薄。直到最近，许多等离子电视还有不少缺点需要克服，包括使用寿命相对较短、有可能长时间在屏幕上留下一些固定的影像、在高纬度地区无法工作等。不过这些问题至少在一些较好的机型中已经得到部分解决。
数码光显背投电视通常比液晶电视和等离子电视都便宜，厚度也往往比它们厚得多。它实际上是背投电视的一种，以前老的背投电视体积较大，而这种新一代背投电视采用数字技术，外形也更为轻巧。数码光显背投电视是利用其后部一块特殊的晶片形成影像，这种由德州仪器公司(Texas Instruments)生产的晶片上包含了数千个小镜子，光源通过这些小镜子反射到显示屏上形成图像。数码光显背投电视的屏幕比液晶电视和等离子电视的屏幕都更简单，也更便宜。它的画面非常清晰动人，而价格也较低，但一个不足之处就是它不如液晶电视和等离子电视那么薄。
大家要注意一些容易引起混淆的术语。像索尼公司(Sony Corp., 又名:新力公司)等部分生产商销售的所谓“液晶”电视，它们的屏幕并不是真正的液晶屏幕，它们实际上属于背投电视，只不过在其后部使用的是微型液晶显示器，而不是数码光显背投晶片。还有一些电视号称是“平面”电视，实际上不过就是普通电视，只是电视机屏幕的玻璃由常用的曲面玻璃换成了平面玻璃。
最后，注意不要将平板电视或是大屏幕电视与高清电视相混淆。目前在市面上销售的许多平面电视、大屏幕电视并不能播放高清电视节目。你可以购买装配有高清电视节目接收装置的普通电视收看此类节目。如果你想买一台大屏幕平板电视，同时又想收看高清电视，你需要在购买时仔细检查一下所要购买的电视是否有高清节目功能。然后，你还须开通提供高清节目的有线电视或卫星电视服务，通过特殊机顶盒收看这些节目，或是使用屋顶天线接收高清电视信号。
