In this modern world we would commonly see only two type of tv (television). These two types are LCD tv and the plasma tv. There are many different in these two types of tv, in term of production, parts, technology and pricing. In addition, both of them, the LCD tv and plasma tv, are also have pros and cons to it and they are fitted to diffenrent type of use depend on the user preferrence.
Plasma TV...?Plasma tv is a falt screen tv which commonly use in a large size television. The screen is produce from two set of thin glass sheet place close to each other. The gap between them is seperated for the light cell which is 100-200 micron wide. There is a layer to protect it. In the plasma tv, the position light cell will be control by the glass sheet. This is happen by running elestric charge into the glass sheet. In each cell will contain the mixture of zenon gas and other noble gas (inert gas).
The plasma tv works by the fact that it can glow by itseft as it does in the fluolesence light. In other word, the gases in the cell will ionised when it is activated by the use of electrical pressure. When it ionised, they will give out electron and this will cause the production of the ultraviolet rays. The emitted ultraviolet ray is then pass through a phosphors and then ture into a visible light. Thus, made us able to see an image on the plasma tv screen. The image that was created is produced from many tiny dot which called "pixel". Each pixel is constructed by a combination of 3 colour cell, which is red blue and yellow cell. From these fact, it is clearly show that why plasma tv has many advantages which will be discuss later.
LCD...?
LCD stand for liquid crystal display. As the name suggest, LCD tv has a LCD screen in which the screen is made as a liquid cryatal display. LCD tv has a flat screen which is contructed by many tiny little colour pixel or monocrom pixel, which positioned itseft infront of the light source or the reflector. LCD tv is also one of the widely used televion in this era. This is because the fact that LCD tv used up lesser electrical power, hence it is suitable for the battery power supply. In the LCD tv, each pixel compose of layers of liquid crystal molecules what is suspended between two transparent electrode which is made out of Indium tin oxide and two polarised filter. The core of the two polarised filter is to be perpendicular to each other.
When there is no liquid crystal in the middle of the transparent electrode, the light will pass the first filter, but it will be block by the second filter before the electricity is supply to the LCD screen. The liquid crystal molecules will be in the chaotic state. This will makes the charge on these molecules place itseft into the small tiny gaps in the Electric Otrd stem. The molecule will place itself into a spiral or cross shape.
The light that pass the first filter will bend by as it pass through the liquid crystal. This enable the light to be able to pass through the second polarised filter. However not all 100 percent of the light are able to pass through. Half of the light intensity is blocked by the first filter and the other half are able to pass through the second filter.
In LCD, when the electricity is supply to the electrode the liquid cryatal molecule will be made parallel to the electric field. This made the decrease on the rotation of the light. If the liquid crystal in the LCD screen is to completely adjust its rotation the light that passes through will also be force to be perpendicular to the second polarised filter. This will produced the complete blockage of light and a black pixel will be made. Hence by controlling the rotation of the liquid crystal it will determine the light intensity that are able to pass through differntly. Thus ,made the pixel to appear at different brightness.
