Whether it is a customer or a practitioner, the customer needs to purchase and communicate with the salesperson. Most of the time, the communication is very blind, because some of the parameters involved do not understand, and there are many people in the industry who often communicate with themselves. It is very unprofessional to understand, and many LED display parameters and terms are not understood, so whether it is a practitioner or a customer, it is necessary to have a general understanding of the common parameter terms of the LED display, which is conducive to the stable progress of the project. It is also conducive to communication with each other, and at the same time, it is a manifestation of being responsible for oneself to customers and projects.
Therefore, Winbond Ying Optoelectronics has sorted out the common parameter terms of LED display screens for explanation, and we will soon become professionals.
what is led
LED is the English abbreviation of light-emitting diode (LIGHTEMITTINGDIODE). The LED in the LED display industry refers to the LED that can emit visible wavelengths.
What is a pixel
The smallest light-emitting unit of the LED display has the same meaning as the pixel in the ordinary computer monitor.
What is dot pitch
The center distance between two adjacent pixels. The smaller the distance, the shorter the visible distance. People in the industry usually abbreviate P to indicate the dot pitch.
What is pixel density
Also called dot matrix density, it usually refers to the number of pixels per square meter of the display screen.
What is LED module (unit board)
It is composed of several display pixels, which are independent in structure and can form the smallest unit of the LED display screen. Typical ones are 8*8, 8*7, etc. There are basic units that have a certain circuit and installation structure, have display functions, and can realize display functions through simple assembly.
What is DIP
DIP is the abbreviation of DOUBLEIN-LINEPACKAGE, dual in-line assembly.
What is SMD/STM
SMT is the surface mount technology (abbreviation of SURFACEMOUNTEDtechnology), which is currently the most popular technology and process in the electronics assembly industry; SMD is the abbreviation of surface mounted device (surface mounted device).
What is LED display
Through a certain control method, a display screen composed of an array of LED devices.
What is in-line (plug-in light), what are the advantages and disadvantages
It means that the DIP packaged lamp passes the lamp pin through the PCB board, and fills the tin into the lamp hole by soldering. The module made by this process is the plug-in lamp module. The advantages are: high brightness, good heat dissipation, but the disadvantages are The pixel density is small.
What is a surface mount module? What are the advantages and disadvantages
Surface mount is also called SMT. The SMT packaged lamp is welded on the surface of the PCB board through a welding process, and the lamp pins do not need to pass through the PCB board. The module made by this process is called a surface mount module. The advantage is: good display effect. The pixel density is large, suitable for indoor viewing: the disadvantage is that the brightness is not high enough, and the heat dissipation of the lamp itself is not good enough.
What is 3 in 1? What are its advantages and disadvantages
Refers to the SMT lamps packaged with three different colors of RGB LED chips are arranged vertically together at a certain interval, which not only has all the advantages of 3 in 1, but also solves the various shortcomings of 3 in 1: complex process and difficult maintenance .
What is three in one
It is to vertically juxtapose three RGB SMT lamps with independent packages at a certain interval, which not only has the advantages of 3-in-1, but also solves the various shortcomings of 3-in-1.
What is dual-color, pseudo-color, full-color display
Different color LEDs can form different display screens. Dual primary colors are composed of red, green or yellow and green. Pseudo-color is composed of three different colors of red, yellow-green and blue. Full color is composed of red. , Pure green, pure blue three different colors.
What is luminous brightness
The light intensity emitted by a unit area of the LED display, the unit is CD/square meter, which is simply the light intensity emitted by one square meter of the display;
What is the brightness level
The level of manual or automatic adjustment of the brightness of the whole screen between the lowest and the highest brightness.
What is gray scale
Under the same brightness level, the technical processing level of the LED display from the darkest to the brightest. The gray level has a variety of descriptions, including descriptions
What is the maximum brightness
Under a certain environmental illuminance, each primary color of the LED display screen is at the maximum brightness and maximum gray level;
What is moiré
That is, when shooting a full-color LED display at work, some irregular water ripples will appear on the screen of the LED display. These water ripples are called "moir patterns" in physics.
What is a PCB board
PCB is (abbreviation of printedcircuitboard) printed circuit board
What is the cell board specification
Refers to the size of the cell plate, usually expressed by the expression of the cell plate length multiplied by the width, in millimeters. (48×244)
What is the resolution of the module (unit board)
It refers to the number of pixels in a unit board, usually expressed by multiplying the number of rows of pixels of the unit board by the number of columns. (Eg: 64×32)
What is BOM
BOM is (abbreviation of billofmaterial) bill of materials
What is white balance and what is white balance adjustment
What we call white balance refers to the balance of white, that is, the balance of the brightness ratio of the three colors of RGB; the adjustment of the brightness ratio of the three colors of RGB and the white coordinate is called white balance adjustment;
What is contrast
Under a certain environmental illumination, the ratio of the maximum brightness of the LED display to the background brightness.
What is color temperature
When the color emitted by the light source is the same as the color of the black body at a certain temperature, the temperature of the black body is called the color temperature of the light source.
What is chromatic aberration
The LED display screen is composed of red, green and blue to produce various colors, but these three colors are made of different materials, the viewing angle is different, and the spectral distribution of different LEDs are changed. These differences that can be observed are called For the color difference. When observing the LED from a certain angle, its color changes. The human eye's ability to judge the color of the real picture (such as a movie picture) is better than observing the picture produced by a computer.
What is the frame rate
The number of times the LED display screen information is updated per unit time is to divide the screen content we see into multiple segments for playback. The frame change frequency is generally about 60, which is almost invisible to the naked eye.
What is the refresh rate
The number of times that the display screen of the led display is repeatedly displayed by the display in a unit time, the higher the refresh frequency, the more delicate the picture.
What is the perspective? What is the viewing angle? What is the best perspective
The viewing angle is when the brightness of the viewing direction drops to 1/2 of the brightness of the normal line of the LED display screen. The angle formed by the two viewing directions of the same plane and the normal direction. Divided into horizontal and vertical viewing angles; the viewing angle is just the direction in which the image content on the display can be seen, and the angle formed by the normal of the display. The best viewing angle is to be able to just see the content on the display, and not flat, the angle formed by the clearest direction of the image content and the normal;
What is the best viewing distance
It is the vertical distance of the clearest position of the image content relative to the screen body that can just see the content on the display screen completely, and is not flat.
What is the point of out of control? Divided into several
Pixels whose light-emitting state does not meet the control requirements, out-of-control points are divided into three types: blind spots (also known as dead spots), constant bright spots (or dark spots) and flash points;
What is a static drive:? What is a scan driver? What is the difference between the two
The “point-to-point” control from the output pin of the driver IC to the pixel point is called static driving, and the “point-to-column” control from the output pin of the driver IC to the pixel point is called scan driving. It needs a row control circuit: It can be clearly seen from the driver board that static driving does not require a line control circuit, which is costly, but has good display effect, good stability, and low brightness loss; scanning driving requires a line control circuit, but the cost is low. Poor effect, high brightness loss, etc.;
What is constant current drive? What is constant voltage drive
Constant current refers to the constant output current value specified in the working environment allowed by the driver IC: constant voltage refers to the constant output voltage value specified in the working environment allowed by the driver IC;
What is the general aspect ratio of the LED display
Graphic screen: Determined according to the displayed content; Video screen: Generally 4:3 or close to 4:3; The ideal ratio is 16:9.
The number of points that a set of control system can control
Communication screen A card: single color, dual color 1024×64; communication screen B card: single color: 896×512 dual color: 896×256; DVI dual color screen: 1280×768; DVI full color screen: 1024×512.
What is nonlinear correction
If the digital signal output by the computer is displayed on the LED display without correction, there will be color distortion, so in the system control circuit, the original computer output signal is calculated through a non-linear function to calculate the signal required by the display. Because of the nonlinear relationship between the front and rear signals, we often call it nonlinear correction.
What is the rated working voltage? What is the working voltage? What is the supply voltage
The rated working voltage refers to the voltage when the voltage is used for normal operation; the working voltage refers to the voltage value of the electrical appliance in the rated voltage range and when working normally: the power supply voltage is divided into AC and tributary power supply voltages. Our actual AC power supply voltages are both AC220V-240V, DC power supply voltage is generally 5VDC 12V solar power supply is generally 12V
What is color distortion
It refers to the difference between the human eye's sensory vision and the display of the same object in the natural world and on the display.
What is a synchronous system and what is an asynchronous system
Synchronous and asynchronous are relative to the computer. The so-called synchronous system refers to the LED display control system that displays the content displayed on the display screen and the computer monitor synchronously; the asynchronous system refers to the pre-stored display data edited by the computer In the display control system, the normal display of the LED display will not be affected after the computer is shut down. Such a control system is an asynchronous control system
What is blind spot detection technology
Through the upper software and the underlying hardware, the blind spots (LED open and short) on the display can be detected, and a report can be formed to tell the LED screen manager. Such a technology is called blind spot detection technology;
What is power detection
Through the upper software and the underlying hardware, the working conditions of each power supply on the display can be detected, and a report can be formed to tell the LED screen manager. Such a technology is called power detection technology.
What is brightness detection? What is brightness adjustment
The brightness in the brightness detection refers to the brightness of the environment where the LED display is located. The light sensor detects the brightness of the environment where the display is currently located. This detection method is called brightness detection; the brightness mentioned in the brightness adjustment refers to the LED display The emitted brightness and the detected data are fed back to the LED display control system or control computer, and then the brightness of the display is adjusted according to this data, which is called brightness adjustment;
What are real pixels? What is a virtual pixel? What kinds of virtual pixels are there? What is pixel sharing
Real pixels refer to the 1:1 relationship between the number of physical pixels on the LED display screen and the actual displayed pixels. How many points are actually displayed on the display screen can only display image information. Virtual pixel refers to the 1:N (N=2, 4) relationship between the number of physical pixels of the display screen and the number of pixels actually displayed. It can display image pixels 2 or 4 times more than the actual pixels of the display screen; virtual Pixels can be divided into software virtual and hardware virtual according to the virtual method: according to the multiple relationship, they are divided into 2 times virtual and 4 times virtual, and according to the row of lights on a module, they are divided into: 1R1G1B virtual and 2R1G1B virtual;
What is remote control? Under what circumstances
The so-called long-distance is not necessarily long-distance. Remote control includes the main control end and the controlled end in a local area network, but the distance between them is not far; and the main control end and the controlled end are within a relatively long space distance. The customer requires or the customer control position exceeds the optical fiber directly. Control the distance, then use remote control;
What is fiber optic transmission? What is network cable transmission
Optical fiber transmission uses transparent glass fiber to convert electrical signals into optical signals, while network cable transmission uses metal wires to directly transmit electrical signals.
Under what circumstances use a network cable? When to use optical fiber
When the wiring distance between the display screen and the control computer is less than 100 meters, use a network cable for transmission; when the distance between the two is less than 500 meters and greater than 100 meters, use a multi-mode fiber, and when the distance is greater than 500 meters, use a single-mode fiber.
What is LAN control? What is internet control
In the local area network, one computer is used to control another computer or connected to other external devices. This control method is called local area network control. The main controller achieves the purpose of control through the IP address of the controller in the INTERNET network, which is called Internet control;
What is DVI? What is VGA
DVI is the abbreviation of DigitalVideointerface, that is, digital video interface. It is a digital video signal interface commonly used internationally.
What is a digital signal? What is a digital circuit
Digital signal means that the value of the signal amplitude is discrete, and the amplitude value is limited to two finite values of 0 and 1. The circuit that processes and controls this western signal is called a digital circuit.
What is an analog signal and what is an analog circuit
An analog signal means that the value of the signal amplitude is continuous in time; the circuit that processes and controls this signal is called an analog circuit
What is a PCI slot
PCI slot is an expansion slot based on PCI local bus (PEDPHERDcomponentinterconnect, peripheral component expansion interface). The PCI slot is the main expansion slot of the motherboard. Almost all the external functions that the current computer can achieve can be obtained by plugging in different expansion cards:
What is an AGP slot
Speed up the graphics interface. AGP is an interface specification that can use 3D graphics to be displayed at a faster speed on an ordinary personal computer. AGP is an interface designed to transmit 3D graphics faster and more smoothly. He uses the main memory of an ordinary personal computer to refresh the image displayed on the monitor, and supports 3D graphics technologies such as texture mapping, zero buffering and alpha blending.
What is GPRS and what is GSM? What is CDMA
GPRS is a new carrier service developed on the existing GSM system through packet radio service (GeneralPacketRadiosrvice), which is mainly used for radio communication; GSM is the "GlobalSystemForMobileCommunication" standard (Global System The abbreviation for communication system), which adopts digital communication technology and unified network standards to ensure the quality of communication and can develop more new services for users to use. Code Division Addressing (CODEDIVISIONMULTIPLEACCess): A new and mature wireless communication technology based on spread spectrum technology.
Where is the use of GPRS technology for the display
