Posts Tagged ‘televisions’

Should You buy a Plasma Television?

Friday, July 24th, 2009
by Graham Taylor

Buying a television used to be easy. There were only a few televisions of varying sizes in most stores and each television used the same technology. Today this is not the case. Shoppers much choose from LCD, Plasma, CRT, rear projection and other technologies when shopping for television. So, should you buy a plasma TV?

A plasma TV is a flat panel television and it has benefits and disadvantages just like every other piece of technological equipment. Therefore, you must weigh the advantages against the disadvantages to decide whether are not to buy a plasma TV. These advantages and disadvantages will be discussed at length.

Lets take a look at the disadvantages of plasma televisions. First, plasma TVs are normally heavier, require more power consumption and run hotter than LCD counterparts. Also, flat panel plasma TVs carry a bigger risk of screen burn in. but this risk is greatly diminished by the fact that most plasma televisions are up to date with the newest technologies. The final two disadvantages of flat panel plasma televisions are the fact that they do not perform well at high altitudes and they tend to have more glare on the screen.

There are also advantages to owning a plasma television. Other technologies cannot provide the superior motion tracking, deep blacks and collars, increased contrast ratio and the large assortment of big screen televisions sizes that plasma technology does. If you are purchasing a television specifically for the use of high definition cable services and Blu-ray picture, then you should probably purchase a plasma television if you want flat screens.

There is a common argument that is made by plasma television producers regarding the use of mercury in the manufacture of other flat panel television technologies. Many flat panel plasma TV manufacturers claim that LCD televisions are dangerous because they contain mercury. However, the amount of mercury is so small and well contained that this argument is a nonissue.

So, should you purchase a plasma television? That argument is largely based on your perception of the advantages and disadvantages of owning a flat screen plasma TV. Consider the following scenarios.

Most homes today are air conditioned and do not rely on a lot of natural sunlight. Therefore, the heat buildup and glare disadvantages of plasma televisions are likely be relevant to the modern home. On the other hand, if you relied mainly on primitive cooling methods and natural sunlight, then you may find that the disadvantages of owning a plasma television are more prevalent in your home.

The wisest decision you can make as a consumer is to fully research the benefits and disadvantages of owning every product you buy. Plasma televisions are no exception. Read the literature about the product, and make your decision. However, make sure to give plasma televisions a thorough look because they tend to be superior in picture and overall utility.

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LCD Televisions facts

Sunday, May 31st, 2009
by Michael Hiltone

The most popular way of generating an image on any modern day television is by the use of LCD television technology (liquid crystal display).

The nature of a television image is that it is constantly changing both in colour and in contrast.

An lcd television has a back light permanently turned on, which is the source of a televisions brightness. To create brightness and darkness it must be able to limit or increase flow of this light.

The inherent properties of a crystal will allow this to occur, as firstly a crystal state is cylindrical in nature and therefore has the ability to allow light to pass through; secondly it has a twisted property which can be accentuated dependant on how much electrical charge is submitted. Increase the current and the crystal will tighten and therefore become more opaque in nature. Reduce the current and it will relax and allow more light to pass through. Do be aware though that the complete restriction of light is impossible as a crystal cannot completely inhibit the transfer of light. Also as each pixel is so tightly arranged to the next, even with polarized glass, you do get a cross contamination from one pixel to another. Resultant issue is an inability to achieve a true real black.

To create colour in an lcd tv, the pixel has three coloured sub crystals which are made up of the primary colours (red, green, blue). The relationship between these crystals generates the colour and hue of the pixel ie the contrast ratio.

The liquid crystals are sandwiched between two pieces of polarized glass " sometimes described as mother glass. The polarization effect of the glass focuses the light source which is how LCD televisions can achieve such razor sharp images. One of these sheets of glass is coated with a special polymer which secures the thousands of crystals required to create an lcd television display.

Across the whole internal construct of an lcd tv`s panel is a matrix of micro thin transparent transistors. The matrix feeds information via electrical currents to each individual pixel which then controls the feed of information and ultimately the colour and temperature of an individual pixel. This then ultimately creates, over the whole matrix within the lcd television, the image.

An lcd television is a complex piece of equipment, that requires multiple processes to correspond instantaneously. The inability to create a true black is always an issue due to light bleed but with further developments in LED specific pixel lighting technology as opposed to a blanket back light the challenge is on to create the perfect screen.

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