Plasma Televisions

The name plasma makes people think of it as a new technology and one would be surprised to hear that these screens have been around for more than 40 years now! Only recently, there has been much improvement in the making of these displays. Plasma televisions (a.k.a. plasma display panels) are emissive flat panel displays where light is created by phosphors excited by a plasma discharge between two flat panels of glass. This plasma/gas discharge uses an inert mixture of noble gases (such as Neon and Xenon). The plasma is sandwiched between two glass panes coated with phosphor material.

The television controller controls the plasma through electronic signals delivered with beams of electrons. Each pixel of a plasma display panel can turn red, green, or blue, and the controller combines them and varies their intensities to produce the entire color spectrum.


Nowadays, most plasma televisions support high definition resolutions such as 800×600 and 1,280×1,024 pixel resolutions. Plasma displays are also quite bright (1,000 lx or higher, with "lx" being the standard of measure for illuminance, lux). Plasma television manufacturers claim that their products can last about 60,000 hours (almost 7 years). However, unwise use of these displays can shorten their lifetime; these include, but are not limited to, setting the contrast to high levels or leaving still images on the display for too long as they can cause burn-ins.

How to calibrate your plasma television?
Plasma televisions are the showroom boast bright, flashy displays that draw you into buying them. However, once you install the television in your home, the same bright, flashy display will be excessive and even damaging to your new appliance. Here is why:

• Plasma televisions in the showroom have their settings configured to attract customers and "out-dazzle" the competing sets sharing the floor. For example, showroom televisions have their brightness levels set too high.
• Each home and television surroundings have different ambient light conditions, which means the optimal settings for one household might not work for the next.
• The default high contrast and brightness levels will prematurely age your plasma screen.
• The default brightness levels consume a tad more power than "normal" and toned down settings.
• Showroom settings might cause eyestrain in the long run.
  

Calibrating your plasma television gives you four things:

• More vivid images optimized for your environment and preferred lighting conditions.
• Longer lifespan for your beautiful television.
• A few more dollars off the monthly power bill.
• A comfortable experience for your eyes and senses.
  

Thus, you need to tone down the default settings of your plasma television, and adjust them to match the conditions of your living room/home theatre surroundings. The question is, how do you know which settings are right or wrong? And before that, what settings do you need to tweak? There are three ways to calibrate your plasma television:

1. Do it yourself (free)
2. Calibration disk (moderate)
3. Professional help (very expensive)

1. Do It Yourself
This method costs nothing but some mind and eye-work is necessary. Important things to note while doing the adjustments, in this order, are:

1. Room lighting
2. Viewing distance
3. Avoiding active modes such as Sports, Dynamics, and Vivid
4. Disabling factory settings and enhancements
5. Adjusting the colour temperature to 6,500K
6. Adjusting the brightness
7. Adjusting the contrast
8. Adjusting the sharpness
9. Adjusting the colour and tint

2. Calibration Disk
These disks provide step-by-step guides and also include test images and videos for adjusting. They also do audio calibration.

3. Professional Help
Have you ever heard of an ISF (Imaging Science Foundation) technician? These guys are the masters of plasma television calibration. ISF calibration, as it is called, will cost you seriously (check their website), but in the end, the expense will be worth it. ISF professionals can adjust settings that few laymen television owners can understand, and they have thousands of dollars worth of calibrating equipment to help them do the job. A plasma television calibrated by an ISF professional will give you stunning results.

LCD (Liquid Crystal Display) Televisions

An LCD television is sometimes called a "transmissive" display, as light is not created by the liquid crystals themselves; a light source behind the panel shines light through the display. A white diffusion panel behind the LCD redirects and scatters the light evenly to ensure a uniform image.

The display consists of two polarizing transparent panels and a liquid crystal solution sandwiched in between. The screen's front layer of glass is etched on the inside surface in a grid pattern to form a template for the layer of liquid crystals. Liquid crystals are rod-shaped molecules that bend light in response to an electric current; the crystals align so that light cannot pass through them. Each crystal acts like a shutter, either allowing light to pass through or blocking the light. The pattern of transparent and dark crystals forms the image.


LCD televisions use the most advanced type of LCD, known as an "active-matrix" LCD. This design is based on thin film transistors (TFT) which are, basically, tiny switching transistors and capacitors that are arranged in a matrix on a glass substrate. Their job is to rapidly switch the LCD's pixels on and off. In a colour LCD television, each color pixel is created by three sub-pixels with red, green and blue colour filters.

An important difference between plasma and LCD technology is that an LCD screen does not have a coating of phosphor dots (colours are created through the use of filters). That means you will never have to worry about image burn-in, which is great news, especially for anyone planning to connect a PC or video game system. LCD televisions are extremely energy-efficient, typically consuming 60% less power than comparably-sized tube-type direct-view televisions.

Older models of these televisions had a delay problem called "ghosting". As the pixels were not able to change colour instantly, fast moving objects left a trace on the screen. Newer models have decreased this delay to 8 milliseconds (recently 4ms), so unless you have a very large screen (more than 40"), the delay is not noticeable at all. Another problem of these screens is the black level. In order for the black colour to show on the screen, the back light must be completely blocked. This poses a problem as there is always a small amount of white light leaking from the narrow space between pixels. So most LCD televisions have difficulty going completely “black” and instead of showing black, a very dark grey is shown. Contrary to manufacturers’ claims, LCD televisions have a limited viewing angle. So at 170 degrees you will see “a picture” but it is not of high quality. Moreover, if you want to use your television as a computer monitor, it is advisable to buy an LCD television that has a computer input, not an LCD monitor that has a television tuner; as the latter acts as a very poor quality television whilst the former introduces good quality in both applications.

Nowadays almost all LCD televisions are high-definition televisions (HDTVs). This means that they are compliant with the recently-approved ATSC standard in North America. There are different resolutions available for LCD televisions. They include: 480p, 480i, 720p, 1080p, 1080i, and 2160p. These are the number of horizontal lines the television can display and the letter that follows shows the type of scan used to refresh the display (interlaced or progressive, for details see CRT televisions). In 480 models, the resolution is about the same as CRT televisions, although they are not called high definition anymore. In 720p models the resolutions that are supported include 1,024×768, 1,280×720, and 1,366×768. In 1080i models the resolution that is supported is 1280×1080 and in 1080p models resolution 1,920×1,080 is supported. In 2160p models, 3,840×2,160 is supported which is even higher than ATSC standard.

Technically speaking, all of these numbers are accurate and useful, but do not put too much stock in them. In the real world, it is difficult to tell the difference between native resolutions once you get into high definition. An important factor is the number of pixels the LCD can support which is dependent on its physical size. For example, a 37" LCD with "only" 1,366×768 pixels has to throw away a good deal of information to display a 1080i picture and there is really no way for you to see more details on a similar 37" LCD with 1080 resolution. This used to be the case when there was a huge price difference between 1080 and 720 versions of LCDs with the same size, but nowadays 1080p native resolution is so common among high definition televisions that you should not even consider it as a factor in your purchasing decision.