Is LED TV the best TV to buy? Are there better TVs than LED TVs?
An LED TV does not have the best picture quality, that honor goes to OLED TV followed by Plasma TV. But this does not mean that LED TV picture is not good, in fact, the latest LED TVs, both LED HDTVs and LED 4K ultra HDTVs, have such stunning high quality pictures that it is hard to believe that there are TVs with better picture quality.
This is because today all types of TVs have good picture quality and to differentiate between the picture qualities of TVs, even expert human eyes find it difficult. Sophisticated instruments are required to compare TV picture quality parameters like contrast, color, brightness, etc. In essence, what this means is that for everyday purpose there is no better TV than LED TV, because LED TVs are competitively priced, economical to run, light weight, long lasting and have very good picture quality.
Is LED TV same as LCD TV
Yes, an LED TV is basically an LCD TV with LED (Light Emitting Diode) bulbs as its backlight. The only difference between an LCD and LED TV is the projection light behind the LCD panel. Both LCD and LED TV have a LCD panel where the picture is formed. The LCD panel is made up of millions of tiny liquid crystals which form each pixel of a picture. The Liquid Crystals are sandwiched between two glass panes. Each Liquid crystal can independently turn 'on' or 'off' with an electric charge to become opaque to block light or become transparent to allow light to pass through. Thus the LCD panel is an electronic screen on which the TV picture is formed, but since the LCD Panel does not produce any light of its own, requires a bright light source at the back of the LCD panel to project the picture on to the TV screen.
The LCD panel in an LED TV is like the film rolls used in the projectors of old Cinema houses. The film has a picture, but for this picture to be projected on the cinema screen, the bright light of the projector is required. Same way the LCD panel picture requires bright lights to be placed behind the LCD panel to project the picture on to the TV screen. These lights behind the LCD panel are called 'back-light'.
When the first LCD TVs were introduced, they had CFL tube lights called CCFL (Cold Cathode Fluorescent light) as backlight. Some time later, LED bulbs become very efficient and bright, so TV manufacturers began to use LED bulbs as back light for LCD TV. To differentiate the LCD TVs with LED backlight, terms such as 'LCD TV with LED backlight' were used first, but in the course of time, LCD TV with LED backlight quickly became just LED TVs.
Now the old type LCD TVs with CCFL backlight are not being seen anywhere because major manufacturers have now standardized on LCD TVs with LED backlight or LED TV. The way the LED bulb backlight is arranged in an LED TV has created new types of TVs like LED Plus TV, Edge LED TV, etc.
LED Plus TV Vs. Edge LED TV
LED Plus TV has LEDs completely covering the back of the LCD panel and each LED or groups of LED can be controlled independently to enable local dimming as explained below. Edge LED TVs have LED bulbs around the edge of the TV and light is evenly projected on to the LCD panel with the use of reflectors. Such an arrangement allows for a very slim TV profile for the Edge LED TV.
In LED Plus TV the LED lights are at the back of the LCD display panel and will make the TV slightly thicker than an Edge lit LED TV. The advantage of LED Plus TV is that ‘local dimming’ is possible, that is individual LEDs at the back of the TV LCD Panel can be put off in areas where the TV picture is dark. This dramatically increases the contrast ratio and gives excellent TV picture quality.
LED TV compared to Plasma TV
The main advantage of LED TV over Plasma TV is that there is never a problem of screen burn-in in an LED TV. Even though Plasma TV has a much better picture quality than LED TV, Plasma TV suffers from Screen Burnin and dim TV picture. LCD TVs are bright and can be viewed even in brightly lit rooms, whereas Plasma TVs are not clearly visible in brightly lit rooms. LED TVs also consume less power than same size Plasma TV and is also much lighter in weight. One big disadvantage of LED TV, when compared with Plasma TV, is that in fast action scenes, LED TV picture becomes blurred. Plasma TV does not suffer from this problem because plasma TV pixels have much higher Response times, that is the pixels 'on' and 'off' or respond much faster to electronic signals.
The picture on a Plasma TV disappears from the screen immediately upon the TV signal being switched off. An LCD TV picture, on the other hand, has a slight retention period on the TV screen even after the TV signal is switched off. This is an inherent problem of LCD panels and, even though LCD panel manufacturers try to overcome this with more frames per second than what is there in the original TV Video broadcast, they are not able to completely eliminate the blurred or trailing image of fast moving objects in a TV picture. This is the main reason why Plasma TVs were the preferred TV to watch sports events, especially in bars and pubs. Since Plasma TVs are being phased out, in future we can expect OLED TVs to take the place of Plasma TVs, since OLED TVs also have very fast response times. LED TVs are catching up with faster response time LCD crystals and by including higher refresh rates or Hz.
Latest LED TV features
Some of the latest features and improvements to LED TVs are as follows
LED TV with high Refresh Rates or Hz
The LCD panel in an LED TV has an inherent problem of picture retention on the TV screen even after the picture signal has been switched off. Even though the period of this picture retention is very minute it is enough to cause a problem in LED TV picture known as trailing image. Trailing image is a blurred image behind fast moving objects in a TV picture - like a fast moving football or a racing car in a car race.
To overcome this problem LED TV manufacturers resort to a technique of having faster refresh rates or more picture frames per second (Hertz) than what is there in the original TV Video broadcast. The trick is to add duplicate frames in-between the actual video frames, the technical name for this is 'frame interpolation'. For example in a 120 HZ refresh rate TV, where a normal video has 60 picture frames per second, special chips in the TV makes a duplicate of the adjacent picture frame and puts it between each of the normal 60 frames per second to create a frame rate of 120 frames per second or 120 Hz. This way some of the blurring in fast scenes can be corrected, but there is a limit. To the question: is higher Hz better for TV? Several TV experts say that higher than 120 Hz does not matter with LED TV, if there is any improvement in TV picture motion blur over 120 Hz, it is not so obvious.
All TV manufacturers have special names for their enhanced refresh rate Hz, like LG: TruMotion and Motion Clarity Index (MCI), Panasonic: Backlight Scan, Philips: Perfect Motion Rate (PMR), Samsung: Motion Rate, Sharp: AquoMotion, Sony: MotionFlow, Toshiba: ClearScan, Vizio: Effective Refresh Rate.
Backlight local dimming in LED TV
In a 'Local Dimming' LED TV, the individual LED bulbs behind the 'LCD Panel' can be dimmed in dark areas of a TV picture and lit bright in areas where there are bright scenes. This arrangement will improve the 'Contrast Ratio' of the LED TV and make blacks appear darker and whites brighter.
Colored backlit LED TV
Some manufacturers are even trying to put RGB colored LED bulbs as backlight of LED TVs to match color of the screen picture. With RGB LED bulbs instead of pure white bulbs, any color of the spectrum can be output by the backlight to match that in the TV picture constantly. Manufacturers are still experimenting with this idea and we are not sure if any production models have been released.
IPS panel display LED TV
IPS stands for In Plane Switching. IPS LED TVs are now considered the top of the range in LED type TVs. LCD panels in an LED TV are mainly of two types: In-Plane Switching (IPS) and Twisted Nematic (TN) type. IPS is the superior technology because it gives much wider viewing angles and much better color to the TV screen. Contrast ratios were not so good in the earlier days, but now with the newer versions of Super IPS screens the contrast and other TV performance parameters have improved vastly.
4K Ultra HD LED TV
The latest LED TVs to hit the market are the super 4K LED TVs with screen pixel dimension of 3840x2160 pixels. When 4K TV compared to HDTV, 4K TV has 4 times the pixel density of HDTV. The 4KTVs pixels are packed so close together that you cannot make out the pixels even if you go close up to the TV.
Hand gesture based remote control for TV
Newest TVs can be remote controlled just by hand gestures or just by the waving your hands in a particular way. This is an innovation brought to the market by Samsung TV first. Gesture Control does not completely get rid of the TV remote control but is limited to just a few of the TV functions like changing channels and controlling TV volume.