Basics of the method The very first samples of TVs with the so-called "LCD lighting", carried out by means of conventional fluorescent lamps, were much inferior in image quality to the same plasma panels. At the same time, the search for more effective solutions to increase the contrast of the picture,
which was considered the most important indicator of the quality of the image on the screen, did not stop.
A direct consequence of such a search was the optimal solution, involving the use of a completely new type of illumination, implemented through LEDs. This method of improving the quality of the image by highlighting it from the inside is called the LED method.
Nowadays, this approach to providing illumination of the LCD matrix screen is basic, that is, used in almost all modern models of television receivers. There are several ways to provide LED illumination of the screen, mainly differing in the location of the LEDs themselves, as well as the control scheme used.
Types of lights
Due to the fact that all existing approaches are somewhat different from each other - individual TV models that fall under this category will have pictures different in their parameters. The most common methods of illumination today are:
The so-called "full array". Pure side or peripheral illumination. The first option, but in the presence of local dimming. Side illumination in conjunction with dimming.
Let's look at each of these methods in more detail. Let's turn to the first of the methods listed above, called a "full LED array". With this approach, individual LEDs are located directly behind the matrix and are evenly placed over the entire surface of the substrate.
In this case, the local dimming effect is not specifically used. From the picture above it follows that this method is very similar to the usual illumination of the television screen through miniature light bulbs. Nowadays, its use is extremely limited.
Side lighting
The second of the considered techniques involves the use of side lighting, carried out without the effect of local dimming. This technology was developed in 2009, and by 2010 it began to be implemented everywhere. Since that time, it has been the most common technique for improving the quality of a television picture.
Thanks to its use, the developers manage to obtain the housings of LCD television receivers with a thickness of no more than 1 inch. This is achieved due to the fact that the LEDs themselves are placed in the side parts of the matrix and transmit a signal to the screen via ultra-thin fiber-optic channels. In terms of the quality of the resulting picture, this method is not much better than that of conventional LCD models. The disadvantages of this method include the presence of illumination at the edges of the screen field.
Full array plus local dimming
The third option for obtaining backlighting is a combination of a full array of LEDs with the simultaneous use of local dimming. The essence of the latter is to change the intensity of illumination by different groups of LED emitters, depending on the gradations of the image itself.
At the same time, in less bright areas of the picture, the LEDs are artificially darkened, and on lighter fragments they are illuminated with greater brightness. Thanks to this technique, it is possible to increase the "black level" in the reproduced image, as well as to achieve its better contrast.
This method is practically devoid of drawbacks and is considered today one of the most effective ways to form a backlight.
Side illumination with simultaneous local dimming
When considering this technology, we draw attention to the fact that when implementing it, an integrated approach is also used, consisting in the simultaneous action of side lighting and the local dimming already discussed earlier. This is achieved due to the fact that LEDs are also placed at the edges (perimeter) of the matrix. To improve the quality of the picture, the scheme additionally introduces darkening of individual areas of the screen with an intensity determined by the nature of the image.
The resulting species field is of good quality, but it is noticeably inferior to the characteristics of the picture formed by the previous method.
Choose the best backlight
Before you buy a TV in a retail outlet - be sure to pay attention to the method used in this model to implement backlighting. Based on the comparative analysis conducted earlier, it is most reasonable to opt for the third option. Making such a decision allows you to get an excellent ratio of the "black level" and the contrast of the reproduced image (at a completely acceptable cost of the television receiver itself).
