LCD

LCD HDTV can be defined or explained in a complex way.  I will try to explain LCD in a simplified manner.

LCD stands for liquid crystal display.  LCD displays use sheets of polarizing material. One layer is coated with a special polymer that holds the individual liquid crystals.  An electric current is passed through the individual crystals, which each crystal then acts like a shutter either allowing light to pass through or blocking the light to create images.  Individual LCD shutters open and close which allow a metered amount of the white light through. Each shutter is paired with a colored filter to remove all but the red, green, or blue  portion of the light.
LCD does not produce it's own light.  An external light source is needed to become visible to the viewer.  The light is usually a series of cold cathode fluorescent lamps although some use white or colored LED's.  LCD's are thin and don't require a lot of power to operate.  LCD TV pixels are turned off or on at a specific refresh rate.  This is where you get the 60hz, 120hz, or 240hz ratings from.  It is the rate in which the image is refreshed.
The lifespan of an LCD TV is debatable.  For the most post LCD TV's have a lifespan of 60,000 hours in a controlled environment.  Many manufacturers have claimed a lifespan up to 80,000 hours or more.  This is, of course, in a controlled environment and used continuously.  It is to note that LCD will have signs of "wear".  This is due to the light source which will dim over time causing the picture you see to dim also.  Therefore, the most important factor to the lifespan of an LCD is the lifespan of the light source.
Some manufacturers have started to product LCD TV's whose light source (lamps) can be changed thus giving you a "like new" picture after it has been changed.

HDTV

As HDTV service grows in popularity so does the stress of understanding not only what HDTV is, but also choosing from the different products and services that come with HDTV. With so much advertising on this subject many people find themselves confused with all the choices that are out there. I am going to try to explain and simplify the many subjects surrounding HDTV.  This blog will also discuss LCD, Plasma, DLP, LED, and other HDTV products and services.

HDTV stands for High Definition Television. First, let's explain what makes a TV high definition.
The picture of HDTV's is derived from combination's of smaller pixels, wider aspect ratio, and higher resolution.

• Pixels — Pixels are small elements on a TV. Pixels are three closely spaced dots consisting of red, blue and green. HDTV pixels are smaller and spaced closer together than non high definition TV's. This gives you more visual detail creating much crisper pictures.
  
  
• Aspect Ratio — Aspect ratio is the relationship of the width to its height. HDTV has a 16:9 ratio while standard definition TV has a 4:3 ratio. This gives a wider view of the picture or image being produced.

• Resolution — The pixels are arranged in horizontal lines on a TV. The more lines you have the better the picture quality. Standard TV's produce 480 lines per frame, while HDTV produce up to 1080 lines per frame. Lines are drawn on the TV screen in a process called scanning. There are two kinds of scanning:
  

1. Interlaced scanning — In interlaced scanning every other line of pixels is redrawn at the refresh rate capability of the HDTV. This is often associated with 1080i. The "i" being interlaced.
   
2. Progressive scanning — In progressive scanning every line of pixels is redrawn at the refresh rate capability of the HDTV. In 1080p the "p" is standing for progressive scan.
   

The #1 misconception of HDTV, I have noticed, is that if you buy an HDTV you now have a high definition quality picture. This is simply not true.

In order to have a high definition quality picture you must have two major components:

• Own or purchase a HDTV
  
• Receive High Definition Service either through a cable, satellite, or over the air provider through subscription or free high definition service.
  

One without the other will not produce the high definition picture we all are looking for when investing in a HDTV.

I hope this blog will be informative to you during your search for different HD products out there on the market. Updates will be posted to be informative on these products and services. I would love to have any of your input on the subject or HD products you may have knowledge of.

Has this better helped your understanding of HDTV?