As is well known, LED displays are playing an increasingly important role in our lives. Everywhere can be seen in the streets and alleys. But many people are not very familiar with it. Today, we will further understand it through some terminology related to LED displays.
1. Pixel to pixel spacing
Pixel: The smallest independently adjustable light-emitting unit in an LED display screen, which is the basic element that constitutes the display image.
Pixel spacing: also known as dot spacing, refers to the distance between the center points of adjacent pixels, and is one of the core parameters that affect display accuracy.
2. Pixel density
The number of pixels contained within a unit area, measured in points per square meter. There is a fixed conversion relationship between pixel density and pixel spacing. The higher the density, the finer the displayed image, but the optimal viewing distance range is also relatively reduced.
3. Brightness index
Brightness refers to the luminous intensity per unit area of a display screen in a specific direction, measured in cd/m ², and is the core performance indicator of full-color LED screens. The requirements for brightness vary greatly in different usage scenarios, and the specific standards are as follows:
-Small distance screen: ≥ 200CD/m ²
-Indoor screen: ≤ 1500CD/m ²
-Half room screen:>2000CD/m ²
-Outdoor (facing south and north):>4000CD/m ²
-Outdoor (facing north and south):>8000CD/m ²
4. Viewing angle
The viewing angle needs to be professionally measured using an angle tester. When the observer is facing the LED screen, the maximum brightness can be obtained. As the observation direction shifts to the left and right, the brightness will gradually decrease; When the brightness drops to 50% of the maximum brightness, the sum of the angles between the left and right observation points and the screen normal is the horizontal viewing angle, and the vertical viewing angle is measured using the same method. The optimal viewing angle refers to the angle between the observation direction and the normal that allows for clear viewing of the screen content, without color distortion, and with the clearest image details.
5. Visual distance
The visible distance is divided into minimum viewing distance, optimal viewing distance, and farthest viewing distance, and the specific calculation formula is as follows:
-Minimum viewing distance (critical distance for presenting smooth images): LED display visual distance=pixel spacing (mm) × 1000
-Best viewing distance (the clearest distance of the image): Best viewing distance for LED display=pixel spacing (mm) × 3000
-Maximum viewing distance: LED display screen maximum viewing distance=screen height (meters) x 30 (times)
Taking P6 specification display screen as an example: minimum viewing distance=6mm × 1000=6m; optimal viewing distance=6mm × 3000=18m.
6. Protection level
The protection level is indicated by the IPXX symbol, with the first X representing the dustproof level and the second X representing the waterproof level. The specific grading standards are as follows:
Dust proof level (0-6 levels)
-Level 0: No dust protection at all
-Level 1: Prevent the intrusion of large solid foreign objects
-Level 2: Prevent the intrusion of medium-sized solid foreign objects
-Level 3: Prevent small solid foreign objects from entering
-Level 4: Prevent solid foreign objects larger than 1mm from entering
-Level 5: Prevent the accumulation of harmful dust
-Level 6: Completely isolate dust from entering
Waterproof rating (0-8 levels)
-Level 0: No waterproof protection
-Level 1: Water droplets splashing into the shell have no effect
-Level 2: When the shell is tilted at 15 degrees, water droplets splashing in have no effect
-Level 3: Rainwater splashing from a 60 degree angle has no impact
-Level 4: No damage caused by splashing liquid in any direction
-Level 5: High pressure water flow flushing without harm
-Level 6: Adapt to the humid environment inside the cabin
-Level 7: Can be immersed in water for a short period of time (within 1 minute)
-Level 8: Can be immersed in water for a long time under certain pressure
For example, an IP65 rating indicates that the product is completely dust-proof and can withstand high-pressure water flow without damage.
7. Grayscale level
Gray level refers to the number of gradient levels between pure white and pure black on a display screen at the same brightness. The higher the grayscale level, the richer the color expression and the finer the details of the picture. The common grayscale levels are 8-bit, 12 bit, and 16 bit.
8. Refresh rate and frame replacement frequency
Refresh Rate: Refers to the number of times a display screen repeatedly displays the same image per unit of time, measured in Hertz (Hz), and is a key indicator of image stability. The lower the refresh rate, the more noticeable the flickering and shaking of the screen, which can easily lead to visual fatigue.
Frame changing frequency: refers to the number of times the display screen updates its content per unit time. Common specifications include 25Hz, 30Hz, 50Hz, 60Hz, etc. The higher the frame switching frequency, the better the continuity of dynamic images and the smoother the viewing experience.
9. Contrast
Contrast is an indicator that measures the difference in brightness between the bright and dark areas of an image, that is, the ratio of brightness between the brightest and darkest parts of the image. Contrast has a significant impact on visual effects:
-The higher the contrast, the clearer and more eye-catching the image, and the higher the color saturation; If the contrast is low, the overall picture tends to be dark and the expression of details is poor.
-For dynamic video display, the impact of contrast is more prominent. High contrast allows the audience to more clearly distinguish rapid light and dark transitions in the image, enhancing the dynamic visual experience.
10. Color temperature
Color temperature is a parameter that describes the color of a light source. When the color of the light emitted by the light source is the same as the color of the blackbody radiation at a certain temperature, the blackbody temperature is the color temperature of the light source. When the light color is blue, the color temperature is higher, and when the light color is red, the color temperature is lower.
11. Pixel out of control rate
Pixel out of control rate refers to the proportion of pixels with abnormal operation in the total number of pixels in the display screen. Pixel loss of control can be mainly divided into two types: one is "blind spot" (blind spot), which means that it cannot be illuminated when needed; The second is the 'constant light point', which means it stays lit continuously when there is no need to emit light.
LED pixels are usually composed of combinations such as 2R1G1B (2 red lights, 1 green light, 1 blue light), 1R1G1B, or 2R1G. If any color light bead in the pixel loses control, it is determined that the pixel is out of control. According to the SJ/T11111-2003 industry standard, the pixel out of control rate for indoor screens should not exceed 0.03%, and for outdoor screens it should not exceed 0.2%, and the out of control pixels should be distributed discretely.
The above are some key terms about LED display screens. I hope this article can help you better understand LED display screens
Post time: Nov-18-2025
