The LED local dimming technology of LCD can help LCD to adjust the brightness of the picture locally, which is not possible for the previous LCD monitor.
LED local dimming technology makes the LCD’s picture quality to a higher level, there is about the technical principle of LED local dimming, let’s go through this article to understand.
What is LED local dimming?
LCD is a non-autonomous light-emitting displays, usually it needs to use the LED as a light source, through the backlight technology to provide light for the LCD screen.
This light-emitting technology leads to the LCD screen contrast is not high, and the overall brightness is low, the visual perception is more general. At this time, in order to display a better picture, LED local dimming technology has arisen.
LED local dimming technology by adjusting the LCD screen area light, so that the bright areas are brighter, darker areas are darker, the overall contrast of the screen is stronger, the visual experience of watching better.
Advantages of LED local dimming technology
Enhanced Contrast
After LED local dimming LCD screen light and dark areas will have a relatively large difference, the black is deeper, the bright screen is brighter, this contrast will make the screen better color rendering, visibility is stronger.
Let’s say, when the picture is all bright objects, you can hardly notice the subject of the content you want to express, and when you try to darken the picture outside the subject, the subject becomes brighter, then the audience can easily notice the subject.
Similar expression of the stage lighting, the surrounding lights off, leaving only one light to the protagonist, when the audience will feel more clear to watch the protagonist, more focused, LED local dimming technology is also based on the principle of the invention of this effect.
Minimizing the halo effect
LCD display screen will have a slight light leakage, so in the dark background, the brighter objects in the screen display will have a diffuse fuzzy halo, this fuzzy halo may also distort the surrounding picture, we call it halo effect.
When tuned with LED local dimming, which reduces the brightness of some areas, the halo effect can be partially eliminated, allowing for a clearer viewing of the picture.
Improved energy efficiency
LED local dimming makes dark areas darker, reduces unnecessary lighting, and only lights important areas, which focuses energy efficiency on necessary areas, reduces energy consumption to a certain extent, and maintains the viewing effect of bright areas while also reducing unnecessary energy waste.
Preserving details
Without the LED local dimming adjustment, even the shadows are brighter, which will make the overall picture look cluttered and unfocused, and the overall picture quality appears to be textureless.
With LED local dimming, the darker areas become darker and the brighter areas become brighter, resulting in a more vivid and realistic overall picture with more layers and a better viewer experience.
Types of LED local dimming technology
Full array local dimming
Full-array local dimming is to precisely control the brightness area by arranging a uniform array of LED lamp beads behind the screen.
This local dimming control method can ensure that the regulation of the area is very accurate, it can do accurate bright areas, but also to retain the shadow area, and reduce the halo effect.
But the full array of local dimming process is more complex, higher production costs, more for high-end series LCD products.
edge light type local dimming
edge light type LCD all LED are arranged in the edge of the display, by the edge of the screen to the center of the light-emitting design leads to the use of LED local dimming technology for dimming, dimming the range is relatively large, the region is difficult to control accurately.
But the edge light local dimming can make the display more thin and light, its manufacturing process is simple, low cost, so the use of a wider range.
direct down local dimming
direct down local dimming technology principle is similar to the full-array local dimming, through the screen behind the arrangement of the LED matrix to regulate, but direct down local dimming relative to the full-array local dimming, the number of LEDs is less, the matrix module is larger, the accuracy is slightly lower than the full-array local dimming, but higher than the edgelight local dimming.
direct down type local dimming process cost is also higher than the edge light type is lower than the full array type, is a more centered option.
Do LED displays need to use LED local dimming technology?
Compared with the LCD needs to be through the LED local dimming technology for local brightness control, LED display as a self-luminous display, it can be through the control software on the LED screen of each LED lamp bead brightness, color and refresh rate for accurate regulation, LED display at any time according to the environment and playback content to adjust the screen display parameters, do not need to use the LED local dimming technology to intervene.
Challenges and limitations of LED local dimming technology
Limited area accuracy
The precision of edge-light local dimming and direct-down local dimming is difficult to control. Sometimes, in the case of too strong contrast, the light that is supposed to enhance the bright area may leak into the dark area, resulting in halo effect.
This situation can be solved by using full-array local dimming, but the full-array type is more expensive, making it difficult to become a popular choice in the market.
Ultra-thin screen performance degradation
The depth of the LED array is limited, so most of the LCD business will make the display into a slim and ultra-thin volume effect, thus making a product publicity gimmick, but this ultra-thin display often leads to a decline in the screen display performance, dark and light areas are difficult to achieve the desired effect, it may be brighter than expected or darker than expected, and sometimes lead to uneven lighting.
Energy efficiency
The luminous principle of backlighting technology has a large energy loss, sometimes even if the monitor screen display does not emit light, but the light behind the light source to provide light may have been emitting light, so energy loss is greater.
This is the LCD has always been the drawback, regardless of which type of local dimming technology is difficult to jump out of this limitation, but the use of full-array local dimming technology can slightly attenuate the energy damage, so that the dark areas to reduce the luminous.
Low Brightness
LCD backlighting principle leads to lower brightness of the display screen, the use of LED local dimming technology can not completely improve this problem, therefore, LCD is only suitable for use at night or in low-light environments, if the sunlight is more intense room, LCD screen viewing visibility is poor.
Compared to LCD, high brightness environment is more suitable for the use of LED display, LED display of high brightness so that the picture will not be affected by the ambient light.
Heat-related problems
LCD’s heat dissipation is poor, due to the heat and lead to the LCD’s component service life decline has also been there, especially the full array local dimming technology, its component density is higher, the heat emitted is also higher, this situation is more serious.
A similar heat generation situation would be better performed by OLEDs and LEDs as self-luminous displays.
LED local dimming and other contrast enhancement technologies
Local Dimming and Dynamic Contrast Ratio
Dynamic contrast is a global dimming process or image parameter modification based on different images to achieve a better display effect.
However, compared to LED local dimming, this global dimming can sometimes result in dark areas being too dark or highlight areas being overexposed, making it difficult to achieve a more accurate and higher quality display.
Local dimming and self-illuminated pixels
Self-illuminated displays, similar to LED and OLED, their picture black and white contrast is very good, LCD dimming is also to simulate the LED self-illuminated display effect, and to make the technical processing. Although LED local dimming technology makes LCD display better, overall, it is still different from LED, and it is difficult to reach it completely.
Which LED local dimming technology should I choose?
User requirements
First of all, of course, according to their own needs to choose LED local dimming technology, if you are a professional video producer, you need a clearer and more accurate display of the screen, of course, is better to choose the full array of local dimming technology.
If you just buy LCD as a small conference room display, or some simple digital signage, in this case, choose edge-light local dimming technology can be.
If it is similar to lecture halls, seminars and other lecture halls for the picture has certain requirements, but will not require too professional occasions, then you can choose direct down local dimming technology.
Scalability
Sometimes need to use LCD and larger devices connected to the picture displayed on a larger device, so we need to take into account the existing equipment and other equipment compatibility, which determines the size of the LCD scalability.
edge-light local dimming as a relatively early local dimming method, applicable to most monitor brackets and power systems, in most cases it can be compatible with other devices, so it is more expandable.
Durability
Most LCD products have a short service life due to the limitations of the light-emitting method.
Based on the craftsmanship and quality of different technologies, edge-lit local dimming displays have the shortest lifespan and are more suitable for less frequent use in home theaters or other similar occasions, direct-down local dimming displays have the middle lifespan, and full-array local dimming displays have the best materials, the most robust structure, and the longest lifespan.
Energy efficiency
For the need to use a large number of computer equipment room, or some environmentalists, the most important focus is on energy efficiency.
Usually, edge-lighting and direct-down local dimming will consume less power than full-array local dimming, which is more suitable for people who are concerned about energy consumption.
After-sales service
After-sales service is also a very important consideration, which determines whether you can quickly find the staff to help you solve the problem, if there is no staff to answer, the original glitch for you may also become a big problem.
Long-term return on investment
Electronic equipment belongs to the investment cost of large items, so in the purchase we need to combine the frequency of use and service life to conedger whether it is worthwhile for us to buy? Will it bring us long-term benefits?
The most expensive full-array local dimming, its long-term return is worth my investment? If we reduce the requirements of the screen, choose the lowest price edge-light local dimming can meet our needs?
All of these need to be conedgered in conjunction with our purpose of use and the benefits of use to consider whether it is worthwhile to purchase.
Conclusion
LED local dimming technology can improve the LCD’s display effect to a certain extent, but each of these local dimming technologies has its own advantages and disadvantages, and we need to choose according to our own needs.
In addition, if for the service life, brightness, picture quality and other more extreme pursuit, may wish to consider the LED display, which in these aspects far more than LCD, of course, the cost budget will be higher.
