some metal halide iodine lamp rare metal is filled between electrodes
high-pressure xenon argon gas and other inert gases are filled in Shi Ying glass tube
our general HID lamps are all metal halide lamps
also known as xenon headlights
Because of their high color rendering efficiency, the luminous efficiency reaches 8-12LM/ W
is widely used in various fields of mobile lighting for automobile lighting in theater, stage and factory
When the p>HID is hot or the lamp is not cooled
Because the inert gas in the lamp is still colliding
It takes more than 23, high voltage
to trigger the reignition to break down the two electrodes in 1NS
At the same time
The inert gas inside is ionized
and collided
. When the voltage drops to more than 2 V
, a communication channel is created inside the lamp
. In order to prevent the lamp from cooling down, a large current (continuous current) needs to be added
. The time is about a few seconds
. During this time, the lamp voltage rises slowly
The arc discharge is successful
and the lamp voltage is about 8-9V
. 23V trigger -2V- voltage duration -85V- normal
LED principle and related knowledge
Release date: 16: 12 on September 6, 26 Article source: China Lighting Business Network visits:
In order to let our customers have a brand-new understanding and understanding of LED display system and related products, and be familiar with our company's business scope. Our company specially arranges the basic knowledge of LED for everyone, so that everyone can improve their professional level and make your future work smoothly.
principle of LED and its control technology
1. what is led?
LED is the abbreviation of light-emitting diode. In the PN junction of some semiconductor materials, when the injected minority carriers recombine with the majority carriers, excess energy will be released in the form of light, thus directly converting electric energy into light energy. When reverse voltage is applied to PN junction, minority carriers are difficult to inject, so they do not emit light. This kind of diode made by injection electroluminescence principle is called light emitting diode, commonly known as LED.
second, the characteristics and advantages of LED electronic display screen
as a modern electronic media, led electronic display screen is irreplaceable by any other media because of its flexible display area (divisible and arbitrarily assembled), high brightness, long life, large capacity, digitalization and real-time performance.
LED electronic display screen is a high-tech information release terminal product that fully utilizes modern information technology, integrates and perfectly combines disciplines such as sound, light, electricity and machinery, and integrates video, animation, subtitles and pictures. LED display screen can also be extended to weak current systems such as network, communication, integrated wiring, monitoring and broadcasting.
what are the specific functions of the led electronic display?
1) video broadcasting
the led display system has a variety of video and audio input sources, that is, the video and audio sources are managed by array. The video and audio switching array has multiple video and audio inputs and outputs, which can introduce various forms of video and audio information sources into the system (such as broadcast TV and satellite TV signals, camera video signals, VCD video signals of video recorders, computer animation information, etc.). The following functions have been realized:
☆ Real-time display of video images
☆. Broadcast of radio and satellite TV
☆ Real-time playback of video signals such as TV, video camera and DVD
☆ Real-time editing and playback of close-up, slow motion and special effects
☆ ☆ Simultaneously playing left and right pictures and characters with different proportions
2. Computer information broadcast
☆ displays various graphics, images and computer three-dimensional animation
☆ There are many kinds of characters and fonts to choose from
☆ The broadcast system is equipped with multimedia software, which can be flexibly input and broadcast
☆ The broadcast modes are: screen up immediately, up, down, rolling, flashing, snow falling, horizontal opening, vertical closing, external expansion, internal closing and so on.
3) Other functions
☆ Equipped with standard network interface, it can be connected with other standard networks, and broadcast network information at the same time to realize network control. Enter the INTERNET through the network system and enjoy the infinite charm of the network.
☆ Equipped with sound card, with sound interface, it can be connected with the square broadcasting system, which can achieve audio-visual synchronization and is very stereoscopic.
Related knowledge
The luminous color and luminous efficiency of single primary color, multi-color and full-color LED electronic display screens and gray scale
LEDs are related to the materials and processes for making LEDs. At present, there are three basic colors: red, green and blue.
a display screen composed only of red is called a single red display screen; A display screen made by putting red and green LEDs together as a pixel is called a two-color screen or a color screen; A display screen with red, green and blue LED tubes together as a pixel is called a three-color screen or a full-color screen.
There are two kinds of diode sizes for making indoor LED screens: Φ 3.7 and Φ 5 matrix blocks, where 3.7 and 5 are diode diameters (unit: mm). In addition, LED dies with different primary colors are often packaged into a whole. The pixel size of outdoor LED screens is mostly 12-32 mm, and each pixel consists of several monochromatic LEDs. The common finished product is called a pixel tube, and the two-color pixel tubes are 2 red, 3 green, 2 red and 4 green. These specifications can fully meet the needs of customers in all aspects.
The matrix part of the display screen is composed of many light-emitting diodes. Firstly, the LED is integrated with pixels, and then the pixels are integrated with modules, and then the modules are assembled into a large screen. The luminous tube is packaged with colorless and transparent large oval silica gel, and a curved reflective bowl is installed in the tube, which greatly improves the brightness and contrast and makes the color more gorgeous!
no matter how to make a two-color or three-color screen with LEDs, in order to display an image, the luminous brightness of each LED that needs to constitute a pixel must be adjustable, and the fine degree of adjustment is the gray level of the display screen. The higher the gray level, the finer the displayed image, the richer the color, and the more complicated the corresponding display control system. Generally, the color transition of images with 256 gray levels is very soft. Therefore, multi-color and full-color LED screens are required to be made into 256 gray levels. For example, multi-color screens can display 65,536 colors and full-color screens can display 16.8 trillion colors. Monochrome screen has no gray scale problem.
classification, application scope and difference of LED electronic display screen
1 display screen can be divided into indoor screen and outdoor screen in a big way, and the biggest difference between them is that outdoor screen should consider the possible impact of outdoor conditions on the screen. Based on the relatively complex working environment of outdoor screen, in order to ensure its long-term stable operation, common protective measures are: waterproof, antistatic, lightning protection, windproof, moistureproof and antifreeze.
2 the display screen is divided into synchronous screen and asynchronous screen from the control mode. The so-called synchronous screen means that the contents displayed on the computer screen are displayed on the big screen point by point at the same time, which is an instant state, while the effectiveness of asynchronous screen is not as good as that of synchronous screen. Users can edit pictures, words and other contents first, and then send them to the display screen for display. Generally, synchronous screen is suitable for playing video information, such as live broadcast of football matches. The asynchronous screen displays text and pictures, three-dimensional animation and so on.
the display screen is all-weather products from monochrome and double primary colors to full color, from indoor to outdoor, and is widely used in:
★ city squares, convention and exhibition centers, electronic advertisements
★ trading centers, bidding centers
★ financial securities system applications
★ transportation, hospitals, communications, electric power
★ industrial and commercial taxation, courts, government agencies. Railway signal lamp
★ industrial control
★ military base command post
★ TV station, entertainment place
★ display system of sports factory and gymnasium, etc.
There are two methods to control the brightness of LED electronic display screen:
One is to change the current flowing through LED. Generally, LED tubes allow continuous working current of about 2 mA, except that red LED is saturated.
another method is to use the visual inertia of human eyes to realize gray scale control by pulse width modulation, that is, to change the light pulse width (that is, the duty ratio) periodically. As long as the repeated lighting period is short enough (that is, the refresh frequency is high enough), human eyes will not feel the light-emitting pixels shaking. Because pulse width modulation is more suitable for digital control, almost all LED screens use pulse width modulation to control gray scale today when microcomputers are widely used to provide LED display content. (R&D Department of Zhengzhou Anjia Electronic Technology Co., Ltd.)
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