Dynamic Range: The Art of “Black”

LED display panels are famous for their long life, high dynamic range, and wide color gamut. Among them, high dynamic range represents high-performance display capabilities in the brightness level dimension, and is the basis for ensuring clear layers, clear details, and gorgeous colors.

In order to achieve a higher dynamic range, the industry has been committed to continuous breakthroughs in brightness. In the field of indoor LED display, the brightness ranges from 1000nit to 2000nit or even higher to achieve high-contrast picture presentation. However, another dimension has been overlooked: doing "black" well.

In fact, "black" and "bright" are equally important to the display screen!

Next, we will break down the nature of dynamic range and the "value of black" based on the characteristics of the real world and the human eye.

What does the real world look like to the human eye?

The brightness range in the real world is as high as 10^(-9) nit~10^(9) nit, from faint starlight to dazzling sunlight, of which the perceptible range of the human eye is 10^(-3) nit~10^(6) nit.

The reason why it is so powerful is related to the self-regulation of the human visual system. Rod cells play a major role in low-light conditions, while cone cells work in strong light conditions.The adaptive adjustment of cells and cones to weak and strong light enables the human eye to instantly perceive a light-dark difference ratio as high as 10^(5):1.

For a display to achieve the expressiveness of the real world in the human eye, it needs a sufficiently high dynamic range capability ("bright enough" and "dark" enough).

Of course, in addition to perceiving high dynamic range, the human eye also has several key characteristics:

1. Human eye nonlinearity

According to the Weber-Fechner Law, the human eye is naturally more sensitive to display effects at low brightness.

2. Mach band effect

The human eye is more sensitive to edges and contours, and the perception of low gray jumps is more obvious.

In summary, from the perspective of human eye characteristics, it can be seen that the value of being "black" lies in: meeting the high dynamic range requirements of the human eye, the low gray sensitivity characteristics of the human eye, and the human eye's jump perception characteristics, which can make the human eye's perception more natural, more accurate, and more comfortable.

PART 2: What kind of "black" is better?

The direct impact of "black" on display performance is that it can improve the dynamic range of the LED screen.

Dynamic range is the brightness range that the display can express. It determines whether the display can retain details in highlights and shadows.

As shown below, a display with a high dynamic range (right) has richer light and dark details, giving people a better sense of reality and comfort.

So what kind of "black" is good?

Combined with the industry's common process level and the real needs of the human eye, the dynamic range index of indoor LED displays should be as high as possible: under 10lux ambient light, the darkest: 0 gray scale brightness ≤ 0.05nit, the brightest: local peak brightness ≥ 600nit, and can achieve precise control of 0.01nit from low gray to high brightness, and color temperature deviation within 200K of different grayscales.

In the future, indoor LED displays should also impact higher dynamic ranges, for example, 0 grayscale brightness under 10lux ambient light ≤ 0.03nit, local peak brightness ≥ 1200nit, brightness control accuracy 0.001nit, color temperature deviation ≤ 100K...

How to do "black" well?

PART 1: Process Dimension

The process determines the ultimate performance of the "blackness" of the LED panel. There are three main ways to improve it:

PART 2: Display and Control Dimension

Good display control technology can allow LED panels to have better "black" color performance under low gray conditions, which is reflected in three key factors: gray brightness, gray scale transition, and perceived comfort. This puts forward "delicate, precise and comfortable" technical effect requirements for LED display and control.

1. The "black" is delicate

The limitations of the hardware's own performance will limit the grayscale levels of the display, making the display not delicate enough and causing a grayscale color cast.

Through Nova 22bit+ technology, double superposition processing in space and time can increase the number of gray levels that the LED can display, making the gray brightness lower and the display more delicate.

2. "Black" is accurate

LED display panel, in low grayREQUEST NOT VALIDWork with industry partners to build reality and create beauty together.