Difference between Local Dimming and Precision Dimming
People who are on the lookout for a new HDTV are often confused by the myriad terminologies and catch phrases that characterize the industry nowadays, and some would probably reminisce about the days when buying a TV was a simple matter of choosing between B&W or colored. Particularly confusing are the terms "local dimming" and "precision dimming", which certain companies are now touting as the next big step in the constant evolution of the TV. What are the differences between each one? The surprising answer is that they are actually a lot more similar than TV manufacturers would have you believe, as you will see from this comparison article.
The Basics
Local dimming relies on the principle of using different local dimming areas across the screen. This results in a more precise dimming, which basically means that "local dimming" and "precision dimming" are the same technologies under different names. The main characteristics of local dimming and precision dimming are more natural looking colors that span a broader range of the colors available in nature. This in turn results in a much better picture quality that you would get with other technologies. In fact, proponents of local dimming and precision dimming claim that such TVs can approximate plasma screen image quality. The term "precision dimming" was first used by Samsung in reference to the local dimming technology used in their line of edge-lit LED LCD HDTVs. The term specifically refers to the technology’s ability to dim LED lights individually rather than in groups.
In Operation
HDTV units with local dimming are constructed with an even array of LED backlights, which is placed behind the diffuser and the liquid crystal display. The diffuser is used to spread the light from the LED backlighting more uniformly across the LCD screen. The terms itself refers to the dimming of the LED backlighting in some parts of the display, allowing for a wider range of contrast ratios and black levels. This makes local dimming HDTVs almost on par with plasma displays in terms of clarity and image quality. Precision dimming on the other hand, uses edge mounted LEDs that allow the precise lighting of diamond-shaped areas on the LCD screen. This gives the same benefits as local dimming HDTVs in terms of higher contrast ratios and deeper blacks. In addition, the diamond patterns also consume less energy.
Advantages And Disadvantages
One of the main drawbacks of local dimming HDTVs is its tendency to display halos around objects that have a darker background. This is caused by light leaking through the liquid crystal shutters. Among some of the attempts made to rectify this issue we see the use of more LEDs and the reduction of LEDs in controlled backlighting blocks, resulting in a much finer degree of control. The main benefit of precision dimming units is its improved image clarity and accuracy. That said, the technology relies in large part on lighting uniformity, and larger units can be quite expensive.
Summary
Local Dimming
- Often refers to the same technology as "precision dimming"
- Uses several local dimming areas placed across the screen
- Results in more natural and lifelike colors
- Is said to approximate plasma sets in terms of clarity
Precision Dimming
- The term used by Samsung to refer to the local dimming units
- Provides many of the same image benefits as local dimming sets
- Larger screened units may be quite expensive
