A Buying Guide for Flat Screen Televisions

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A Buying Guide for Flat Screen Televisions

Flat screen televisions have overtaken conventional CRT (Cathode Ray Tube) television sales all over the world. CRT televisions sales accounted for less than 10 per cent of the 237 million televisions sold worldwide in 2012. LCD TVs are the largest selling flat screen televisions globally, followed by LED and Plasma. A number of new technologies such as 4K and OLED have rejuvenated the flat screen television market and offer a number of benefits to consumers.

About Flat Screen Televisions

The invention of flat screen displays dates back to 1964 by researchers working at University of Illinois. The technology remained underutilised and underdeveloped for decades until the 1980s because of low commercial demand and dominance of CRT technology. The computing revolution of the 1980s spurred the development of flat screen technology in devices like PDAs and mobile phones. Flat screen technologies, particularly plasma and LCD, eventually found their way into television screens. User adoption of flat screen TVs remained low, however, because of high prices. Prices started dropping at the turn of the century and by 2003, flat screen television sales had overtaken CRT sales globally. By 2005, LCD TVs were the single largest selling TV type the world over with stiff competition from plasma. In 2012, plasma technology began to fade out with LCD (as LED and CCFL) accounting for up to 80 per cent of all global TV sales. A number of new technologies have been developed for flat screen TVs that offer better performance than LCD or plasma. These include 4K and OLED. Prices for these technologies continues to remain high, however, affecting user adoption. LCD remains the single largest selling flat screen technology in the world and finds use not just in TV, but also computer monitors, laptop tablets, mobile phones, digital cameras, etc.

Buying Flat Screen Televisions

Flat screen televisions utilise a number of different technologies such as LCD, LED, Plasma, OLED, etc. A television represents a significant investment. Any purchase decisions must be arrived at after considering a number of factors such as underlying technology, size, contrast ratio, etc. Some of these can be seen below.

Flat Screen Television Display Technologies

A number of technologies are being utilised to manufacture flat screen televisions. The prominent among these are LCD, LCD LED, plasma, and OLED. For smaller screens, technologies such as AMOLED have also been developed, though they haven't found their way to television sets so far. The five different television display technologies can be seen below:

LCD

LCD is the most popular TV display technology in the world. LCD is classified as a 'backlit' technology. That is, the TV screen is lit from the back by a set of CCFL lights. A matrix of TN crystals controls the amount of light filtering out to the screen which helps in the production of images and colour.

LCD LED

LCD LED utilises the same principles as conventional LCD screens, albeit with one crucial difference: instead of CCFL, they make use of LED lights. LED lights are more efficient than CCFL and produce crisper, brighter images. LCD LED is the second most popular TV display technology after conventional LCD.

Plasma

Plasma is another backlit display technology. The screen contains cells filled with ionised gases. Any electric current passing through the cells causes them to glow and emit light, which can then be filtered to produce images. Plasma technology produces better images than LCD TVs, but cannot be produced economically in sizes smaller than 32 inches. They also draw a significant amount of power. These two factors have contributed to a drastic reduction in plasma TV sales the world over.

OLED

OLED screens utilize an organic compound that emits light when electrically charged, which is then filtered to produce images. Unlike LCD and Plasma, OLED is not backlit. The picture quality, consequently, is much better. OLED screens can also be made exceptionally thin and are also flexible. However, high costs and technological hurdles in producing large screens have affected their widespread use in televisions.

As mentioned above, LCD is the most popular among these four technologies followed by LCD LED. Plasma technology has largely been abandoned in favour of LCD, while OLED is still in its nascent stages and priced extremely high. LCD or LCD LED represents the most cost-effective buy of the four technologies.

Flat Screen Television Resolution

All flat screen TVs are classified as 'High Definition' (HD). Resolutions of 720p (1280 x 720) and above are classified as HD. Standard Definition TV (SDTV), in contrast, has resolution of either 480p or 576p. In television technology, the higher the resolution, the better the picture quality. TV resolution is expressed as the number of vertical pixels suffixed by either 'p' or 'i'. 'p' stands for progressive scanning, while 'i' stands for interlaced scanning. In the former, the image is produced by drawing each line of the frame sequentially. In the latter, every alternate line is drawn, which saves bandwidth but leads to poorer quality. Interlace scanning is a deprecated technology that is found mostly in older television sets. Flat screen TV resolution can be classified as follows:

Type

Actual Resolution

Total Pixels

Description

576p

852 x 576

490,752

Classified as SD resolution, 576p is found only in older LCD TVs.

720p

1280 x 720

921,600

720p is classified as 'HD' resolution. Almost all TV sold today support 720p resolution at least.

1080p

1920 x 1080

2,073,600

Also called Full HD, 1080p resolution delivers crisp, high quality images.

1080i

1920 x 1080

2,073,600

The same resolution as 1080p, albeit with interlaced scanning. The image quality is poorer than 1080p but better than 720p.

4k Ultra HD

4096 x 2160

8,847,360

4k is classified as Ultra HD and supports a resolution four times as high as full HD (1080p). The resulting image quality is exceptionally high, although uptake of 4k TVs is hampered by high prices and lack of supporting hardware.

TV Resolution and Media Devices

A television set can only display the resolution supported by the input media device (video game console, Blu-Ray/DVD player, set-top box, etc.). DVD players usually support a resolution only as high as 720p. Using a 4k UHD TV with a DVD player, therefore, would show pictures only in 720p, not 2160p. Therefore, any purchase decision about flat screen television resolution must take into account the display resolution of the media device.

Flat Screen Television Screen Size

Flat screen TVs are meant for large screen viewing. The higher resolution is suitable for screen sizes of 32 inches and up, although smaller TVs are also available. The preferred screen size varies according to the distance of the TV from the viewer. The closer the viewer sits to the TV, the smaller the screen size requirement. General guidelines for selecting flat screen TV screen size depending on viewing distance can be seen below:

Screen Size

Viewing Distance

Description

23-27 inches

3 to 5.5

Small screens are appropriate when the TV will be placed very close to the viewer. At a distance greater than 6 feet, however, small screens tend to become ineffective.

28-32 inches

4.5 to 7.5 feet

Up to 7.5 feet, screens smaller than 32 inches are quite effective. This is appropriate in small bedrooms or study rooms where the viewer will sit quite close to the TV.

33-41 inches

5 to 10 feet

40 inches is the preferred screen size for mid-size bedrooms and living rooms.

42+ inches

10 feet and up

TVs above 42 inches are classified as 'large screen' and are recommended for larger bedrooms.

Flat Screen Television 3D Support

3D televisions imitate the 3D effect found in theatres. Most manufacturers have a range of 3DTVs which utilise either active or passive 3D. The primary differences between the two types of 3D technology are:

Active 3D

Active 3D TVs utilize a pair of expensive 3D glasses that constantly sync with the TV to produce a crisp, high quality 3D effect. These glasses tend to be expensive and are quite heavy, but the overall image quality is very high. They are called 'active' because the glasses are battery powered and actively work with the TV.

Passive 3D

Passive 3D TVs use glasses with coloured lenses to produce the 3D effect. This is the same as the 3D in movie theatres. Since the glasses must filter out some light to create the 3D effect, overall picture quality tends to suffer. On the plus side, passive 3D glasses are extremely cheap, light and comfortable to wear.

Other Flat Screen Television Features

Besides resolution, screen size and display technology, there are a few other factors that must be considered when buying a flat screen television. Some of these are:

Contrast Ratio

Contrast ratio is defined as the ratio of the whitest white to the darkest black in any image. Thus, a contrast ratio of 100:1 means that the brightest white is 100 times brighter than the darkest black. TVs with high contrast ratio produce better contrast, darker blacks, and an overall brighter image. Unfortunately, there is no industry standard for measuring contrast ratio and each manufacturer tends to utilize its own methodology. Comparing contrast ratio between manufacturers, therefore, can be misleading. However, contrast ratio is a useful figure when comparing models from the same manufacturer. Typically, higher contrast ratio equates to better image quality.

Refresh Rate

Refresh rate is the number of times the screen redraws itself every second. It is expressed in Hertz (Hz). A refresh rate of 60Hz, therefore, means that the TV screen redraws itself 60 times every second. Most flat screen TVs have a refresh rate between 120Hz all the way up to 600Hz. A high refresh rate is desirable when viewing quick changing action, such as an action movie, a football match or a video game. Sometimes, refresh rate is also called 'response time'.

Ports and Connectivity

A flat screen television needs to accommodate a number of accessories and media devices. A large number of ports is highly desirable. HDMI, Component and Coaxial ports are the most common. HDMI is the standard connecting cable for high definition media such as Blu-Ray players and video game consoles. Component cables are used to connect DVD players, while coaxial ports are used for connecting ordinary cable wire. Some TVs also have USB ports for connecting USB storage drives, and optical ports for connecting high quality surround sound systems.

How to Buy Flat Screen Televisions on eBay

eBay has a large inventory of attractively priced flat screen televisions. To buy flat screen TVs on eBay, go to the eBay UK homepage and search for flat screen TV in the Sound & Vision category. From the search results, choose Televisions category in the left pane. The searches can be further filtered as per different criteria. Searches can be filtered according to screen size such as less than 20 inches , 20-29 inches , 30-39 inches , etc., by brand - Samsung , LG , Toshiba , to name a few - and by display technology: LCD , LED LCD , Plasma . Searches can also be further narrowed by maximum resolution - 1080p , 720p - by 3D features such as Active 3D , and built-in digital tuner .

Conclusion

Flat screen televisions have overtaken CRTs as the largest selling television type globally. Flat screen TVs utilizes different display technologies such as LCD, Plasma, OLED, etc. Screen size, resolution, 3D, contrast ratio, refresh rates and connectivity are some important considerations when buying flat screen televisions. Affordable flat screen televisions can be bought from eBay's extensive inventory.

 
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