LCD Televisions facts
LCD is an abbreviation for Liquid Crystal Display and this is the most popular method used by lcd television manufacturers.
The nature of a television image is that it is constantly changing both in colour and in contrast.
To create different levels of brightness and contrast there must be a mechanism to enable and restrict the amount of light passing through the lcd television. All LCD televisions have at the back of the appliance a backlight.
The cylindrical property of a crystal allows light to flow through it. The twisted element of a crystal allows the regulation of the amount of light passing through. The amount of twist is dependent on the amount of electrical current passing through. Increase the current to tighten the crystal and therefore reduce/prevent light passing through ie dark scenes. Decrease the current to relax the crystal and allow light to flow through freely ie light colours. The complete restriction of light is impossible on this method though as however much current is passed into a crystal it can never fully prevent light passing through. Also, the close proximity of other pixels means light seepage to neighbouring crystals although this is kept to a minimum with polarized glass (see later). This is why it is well documented that LCD televisions cannot achieve and will not achieve a real true black.
The colour issue is created by sub dividing each pixel with three colour elements/crystals ie red, green and blue (primary colours). The interaction of these three colours creates the colour palette (contrast ratio) of the television.
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.
The driving force of the lcd television is the matrix of transistors which disseminates the information to each of the individual pixels. By distributing the information effectively, the appropriate pixel produces the necessary colour and hue, and as this can be performed upto 100 times a second, this is more than enough to create a very fluid and accurate 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.
Tags: LIVE TV
