With the development of technology, the LED screen point spacing smaller and smaller, the display effect is getting better and better, has become the main means of displaying of an outdoor publicity, indoor exhibition, command and meeting.
Since 1923, Rousseff developed a light-emitting diode, there has been a hundred years of history.
On the basis of light-emitting diodes, through certain control methods, the LED device will form an array, thus forming a display screen.
Each LED represents a pixel and the LEDs in an LED display are organized into different columns and rows to form a grid-like structure.
When specific content is to be displayed, the desired image or text can be created by controlling the brightness and color of each LED.
1. LED screen basic components
LED unit board:
this is one of the core components of LED display, which is composed of LED module, driver chip and PCB circuit board.
Control card:
used to control the LED unit board, can control 1/16 sweep of 256×16 points of the two-color screen, can be assembled with cost advantage of the LED screen.
Connecting lines:
including data lines, transmission lines and power lines.
The data line is used to connect the control card and LED unit board, the transmission line is used to connect the control card and computer, and the power line is used to connect the power supply to the control card and LED unit board.
Power supply:
Generally used switching power supply, 220V input, 5V DC output.
2. The classification of LED screen
Single-color LED display:
including red LED electronic display, white LED electronic display, green LED electronic display and so on.
Two-color LED display:
red, green two-color, can display red, green, mixed color (yellow).
Full-color LED display:
red, green, blue three-color, 256-level gray scale full-color display, can display more than 160,000 colors.
In the market to occupy a major position is the full-color LED display, this article on the full-color LED to introduce.
3. Package Type
Its full-color LED display package, commonly COB package and SMD package.
SMD:
LED devices with pins or pads mounted on the PCB, these devices contain encapsulated LED chips that are soldered to the PCB through surface mount technology (SMT).
SMD packaged LEDs have a distinctive independent lamp bead structure, and each lamp bead is an independent point light source.
The SMD package is limited by the physical size of each bead, usually slightly larger than the COB package component size, the point pitch is correspondingly larger, so the common indoor models are basically more than 1mm, outdoor models pixel pitch is generally more than 2mm.
SMD is a point light source and may be able to see the pixel structure when viewed at close range, but color consistency can be ensured by binning the optical performance of individual lamp beads.
For subsequent maintenance, individual lamp beads are easy to replace when damaged, and maintenance is relatively simple.
COB:
Directly encapsulate the LED chip on the PCB board, then use polymer material to bind and wrap it to form a flat light source. This approach eliminates the brackets and pins in traditional packages, reducing component size and making the package more compact.
COB package can achieve smaller package size and higher pixel dot density due to the removal of the lamp bead’s shell, which helps to reduce the pixel pitch of the display and improve the display finesse, such as the P1.25, P1.8 and other series that are currently on sale, which can be easily realized by COB package.
As a surface light source, COB can provide more uniform brightness and wider viewing angle, reduced granularity and softer display interface for close viewing.
The LED chip of COB package is directly wrapped by the protective material, which usually has better dustproof, moistureproof and shockproof performance. After upgrading, the COB display of Zhongpinrui is able to provide 4H hardness on the surface, which is able to avoid the damage of lamp beads due to bumping.
4. The Chip Installation Method:
At present, the LED chip installation is common is positive and reverse mounting; the difference between the two is as follows:
Positive mounting:
From top to bottom, they are: electrode, p-type semiconductor layer, light-emitting layer, n-type semiconductor layer and substrate.
The heat generated by the pn junction in this structure must be conducted to the heat sink through the sapphire substrate.
The poor thermal conductivity of the sapphire substrate leads to poor thermal conductivity in this structure, thereby reducing the luminous efficiency and reliability of the chip.
Flip-flop:
From top to bottom are the sapphire substrate, N-type semiconductor light-emitting layer, P-type semiconductor layer and electrodes.
Compared to the front-mounted chip structure, the heat generated by the PN junction in this structure can be directly transferred to the heat sink without passing through the substrate.
In the flip structure, both the p-electrode and the n-electrode are on the bottom surface, avoiding the blocking of light and improving the efficiency of light output.
LED display with its unique advantages and a wide range of application prospects are changing our visual experience, bringing more color and vitality to our lives.
With the continuous progress of technology and the continuous expansion of application fields, LEGIDATECH believes that LED display will play a more important role in the future to create a better visual world for us.
Author； Lucy
FAQ
1.What is the service life of LED display?
The service life of a high quality LED display is 11 years without any human damage.
- What are the main applications of single color LED display?
Taxi LED displays are usually single color LED displays. This type of display mainly shows one color and is usually used to display advertisements on top of cabs, as well as to display road sign information on the front and rear sides of buses.
The characteristics of monochrome display include high brightness, single color display, through the control software will be edited image text and the corresponding control commands transmitted to the control part of the display system.
Then according to the user’s choice of display mode page by page cycle to display the user’s edited image text.
