LCD TVs > DM Technology LCD TVs

Conventional CRT TVs are almost a thing of the past – the future belongs firmly to flat screen TVs. The sizes and colours of flat screen TVs available today are many and varied, but so too is the quality.

In general, there are two major product categories: LCD (Liquid Crystal Display) and Plasma TVs.

As there are only a few small plasma TVs the choice between LCD and plasma only really becomes relevant if you are looking at a 37 inch or larger TV screen. While both systems offer a high image quality, potential buyers should consider the following issues before purchasing.

As with many things in life the choice of the right television depends on the way it is used. Where should it be placed? Do I want to enjoy movies at cinema quality or to play console games instead?

LCDs work with liquid crystals. These create an image by breaking the light in a certain way. To avoid reflections and other interferences most devices are featured with matt fronts. Compared to plasma TVs colours are more luminous and provide brilliant colours even in bright rooms. However, many TVs have problems displaying a deep black, which can sometimes appear faded. In addition, most will only deliver a high quality image if the viewer sits directly in front of it. If you’re watching from more than a 45 degree visual angle (i.e. outside the principal axis of the TV) the contrast is reduced and the image can appear grey. This is a result of the LCD backlight format.

Plasma devices were at the forefront of the flat screen movement. The technology is based upon ionised gas or plasma, which is illuminated through electronic impulses. The devices deliver true colours even outside the principal axis. As plasma has a very short response time it is perfectly suited for quick image changes such as sport broadcasts.

However, one problem with plasma TVs is the so-called burning-in or after image. Do you watch a lot of non-standard format videos (black bars) or play console games with static graphics? If this is the case, the overcharging of the light beams can sometimes burn a visible pattern into the TV screen. This can also occur through static TV station logos. This is much more unlikely with newer plasma models but the risk should still be taken into account.

The resolution and to a lesser degree the contrast determine the image quality and sharpness. Flat screens feature single fields of determined points which produce light patterns known as pixels. The multiplied horizontal and vertical amount of pixels, for example 640x480 or 1280x720, represents the resolution.

Currently digital content is delivered in three formats: 480i/ 480p (704x480 widescreen/ 640x480 4:3 format), 720p (1280x720) as well as 1080p and 1080i for antenna reception (1920x1080). Products with more than 900.000 pixels (1280x720, 1366x768 or 1920x1080) are defined as high definition (HD). They are ideally suited for broadcast or movies in HD.”HD ready” is an industry standard confirming the quality. Other common industry standards are “HD-Ready 1080p” and “Full HD”.

“HD-Ready” means that the TV is able to show high definition broadcasts with a resolution of 1280x720. This resolution is necessary to carry the “HD-Ready” logo. “Full HD” and “HD-Ready 1080p” currently offer the maximum resolution of 1920x1080 and therefore even better images. “HD-Ready” devices can also receive “Full HD” signals but will display them in a reduced format. With that said, only a few TV stations are broadcasting in HD quality at the moment. The highest resolution is currently deployed by DVD and Blu-Ray players.

The contrast ratio refers to the brightest and darkest light value, which can be displayed at the same time. LCDs should have a ratio between 500:1 and 1500:1 (bright:dark). Plasma TVs start at 1200:1; very good contrast ratios start at 1900:1. Plasma technology hasn’t yet reached a perfect black value as the remaining single pixel discharge creates a dark grey illuminated panel, which is balanced by a higher contrast value. TVs with high contrast values show black scenarios in a true black and many detailed subtle shadows. In comparison, TVs with a low contrast appear grey in black areas and the whole image can look rather flat.

For TVs in living rooms a contrast of at least 400:1 is recommended. For rooms with predominantly artificial lighting like home cinemas you should aim for a contrast of at least 2000:1.

Some manufacturers also have values for dynamic contrasts. These adjust the background lighting according to the image content. For example, when watching a film like “Ice Age” which is dominated by light colours, the dynamic contrast is very high. For dark movies such as “Alien” the TV automatically decreases the contrast. Good dynamic contrast values for light and dark scenarios start around 5000:1. However, the dynamic contrast cannot compensate for an original low contrast value.

For better colour handling most devices have an additional colour enhancer which optimises the fundamental colours. This should have at least 10 Bits.

Most TVs today feature good integrated speakers with at least 15 x 15 watts. However, those values do not reveal any detail about the volume range or sound quality. As the real sound quality is dependent on the actual processing and the proportions of the room in which it is played, product reviews and tests can offer valuable information. If purchasing a large plasma TV attention bear in mind that stand and speakers are often sold separately. On the other hand, with large LCDs they are usually included.

The transfer from analog to digital TV has already begun in the UK. If you don’t have a cable connection or satellite reception with the relevant receiver, you should ensure that your new TV supports DVB-T (Digital Video Broadcasting Terrestrial) either via an integrated or separate receiver. However, traditional antennae and cable signals are often not as good as displayed as with conventional CRT TVs since they were built for HD. Flat screens have the advantage for digital signals, DVDs or video games.

It is worth taking a closer look at the devices which you will want to connect to the TV. Relevant connections should be an integral part of the shopping list. To avoid a complicated exchange of cables it is also worthwhile ensuring that the model you choose has several plug and socket connections.

While SCART connections are the most popular audio and video connections, HDMI enables the highest quality digital transmission, which is ideal for flat screens. HDMI already comes as standard with new high quality DVD, multimedia and Blu-Ray players.

To connect PC or data storage special PC and USB connectors are needed. If a particular connection is missing it usually can be refitted at an extra charge.

The power consumption plays an integral role when choosing a flat screen TV. At an average viewing time of four hours a day 100 watts more can easily account for additional expenses of as much as £300 per year. LCDs usually consume less energy than a similar size of plasma TV. Small LCDs are available with an energy consumption of 120 watts and generally should not have more than 200 watts. A plasma TV with a 37 inch or 94 centimetre screen should not consume more than 260 watts and generally should not exceed 380 watts.

LCD TVs are usually 15 to 50 inches in size. However, high end products can have a screen size of up to 65 inches (165 centimetres). Prices can range from £300 to £2,500 or more for devices starting at 30 inches.

Small LCD TVs are available from £100. Although the same characteristics are important when purchasing a LCD device less than 37 inches in size, lower resolutions are sufficient as well. HD quality is not needed. As some LCD computer screens can also be used as TVs it is possible to kill two birds with one stone when purchasing a smaller device. There are also 9.6 inch portable LCD devices.

Plasma TVs which are solely available from a 100 centimetre screen size onwards are usually cheaper than comparable LCD TVs. Since the overall production of LCD TVs is more expensive only recently larger LCDs became available. While this situation has changed slightly they still tend to be more expensive than plasma devices.

For different screen sizes the following viewing distances are recommended:

Tip: TV sizes are usually stated in inches. One inch equals 2.54 centimetres. If you watch a lot of cinema style movies the TV should support 16:9 formats. Also, depending on the TV size various viewing distances are recommended. For a 30 inch TV the recommended viewing distance is between 1.15 and 2.3 metres, for a 55 inch TV between 2.00 and 3.95 metres respectively.

If all these points are considered it should be easy to choose the right TV for your individual requirements. If you plan to mount the TV to the wall you should consider a smaller sized device and ensure that the wall fixture is able to carry the weight of the TV. There are different fixtures aligned to the different TV models. In transport plasma screens should be kept upright as otherwise the screen could break under its own weight. There is no danger with LCD devices.

Large TVs are not only deeper and heavier but also radiate more heat. Ideally the devices should be placed with some distance to the wall. Also, pay attention to the ease of use. If possible test if the menu follows a logical set up. A timer and electronic TV guides can also add some comfort.

The pros and cons of LCD and plasma TVs summarised:

New models are rolled out in ever-shorter periods of time and the choice of features is larger than ever before. More and more devices now have image-in-image and gallery features. The gallery feature is essentially a standby mode to show high resolution images either from your photo collection or stock images. Many manufacturers also offer storage card readers and USB ports to connect MP3 player and digital cameras to the TV. Some devices even offer WLAN and Internet connections.

Finally, it can be safely said that plasma TVs are more suitable for home cinemas, where a larger TV screen is required for the best experience. For devices of less than 37 inches LCD technology is more suitable, while between 37 and 42 inches customers are pretty much spoilt for choice. However, the subsequent costs (such as energy consumption) of plasma TVs are usually higher.

With all this said, the most important thing is to get a personal experience of the TV you’re considering. A great starting point is the review section of the Ciao community, which can help you find the best possible TV for you.