Classification of LED Display Screens

LED electronic display screen is an electronic display, which is combined with computer technology, information processing technology, electronic technology, phonology, chromatics and other high and new technologies. The LED display screen can be divided into monochrome screen, double color screen and full color display. As the name implies, the monochrome screen is composed of a single color of LED (see figure 1). A pixel display which is in the red and green LED is called double color screen or color screen (see figure 2). And a pixel display consists of the red, green and blue LED is called the tri color screen or full color screen(see figure 3).

Full color display of LED screen can be divided into indoor and outdoor screens. In general, there are two driving methods, one is the change of current LED whose operating current had better be set below 20mA, and the other one is that using human visual inert, gray control can be realized with pulse modulation. People’s feeling about the average brightness of pixel depends on its duty ratio, which can change periodically. As long as the cycle is short enough, human eyes will not feel its duty ratio.

With the improvement of green chip brightness and the drop in price, the full color display is being popularized and promoted at unprecedented speed. Especially, the appeal of Beijing “Green Olympics” makes market prospects of the full color LED display more and more attractive. With the development of more than ten years, the progress of domestic display manufacturers is very fast. However, compared with the developed countries of Europe, America and Japan, there is still a certain gap, especially in the packaging technology of LED display devices and design level.For more information, please visit our website:http://www.analogtechnologies.com/product-LED-Related-Products.html

The Definition of Signal-Noise Ratio

SNR (SIGNAL-NOISE RATIO) refers to the ratio of signal and noise which is in an electronic device or electronic system. The electronic signals come from external device and need to be processed through the equipment, and the noise is additional signal without rules and does not exist in the original signal, and this noise does not vary with original signal.

The unit of signal-noise ratio is dB, and its calculation method is 10 lg (PS/PN), in which PS represents the effective power of the signal and PN represents the effective power of the noise, and they can also be converted to voltage amplitude ratio relations: 20 lg (VS /.vn), VS represents the valid value of signal voltage and Vn represents the valid value of noise voltage. In audio amplifier, the higher the signal-to-noise ratio, the better performance it will have. Please see the below figure.

For more information, please visit our website:http://www.analogtechnologies.com/thermistor.html

What Are the Key Features of TEC Temperature Control?

One of the attractive features of thermoelectric technology is that it offers an incredible degree of control ability. With a properly “tuned” controller, it is possible to maintain systems well within 0.1 degree Celsius of set point. The key features are:

• Precise case temperature control.

• High stability even for DUTs with dynamic heat load.

• Very fast thermal response and short temperature setting time.

• Both cooling and heating functions.

• Compact.

• No vibration.

• Energy saving in many cases.

The following is the picture of the TEC controller of Analog Technologies.

For more information, please visit our website:http://www.analogtechnologies.com/tec-controller.html

Analysis of LED Market Prospects

LED is the abbreviation of light emitting diode, which is a solid light emitting device of semiconductor. Using light emitting materials of solid semiconductor chips, carriers in semiconductor will composite, cause photon emission and produce light, when the two ends of LED are with forward voltage. LED can directly emit red, yellow, blue, green, green, orange, purple and white light.

Our country has huge lighting market of LED and also has strong industrial foundation of lighting. With the development of semiconductor lighting technology, performance improvement of LED lighting and the reducing of cost, China’s LED lighting market outlook will gradually appear.

(1) The huge demand of lighting.

In our country, lighting market is very huge because traditional lighting sources have disadvantages of big energy consumption, low brightness and unsafe. LED lighting will replace the traditional light source and lamp.

(2) A good lighting industrial base.

As lighting industry foundation is very strong, our country is the world’s largest producer of lighting sauce and light lamps. According to statistics of China Lighting Electric Appliance Association, in 2010, the outputs of national incandescent lamps are 3.8 billion and fluorescent lamp production are 6.69 billion, of which the yields of fluorescent lamps of straight tube are 1.83 billion, the yields of ring-shaped fluorescent lamps are 1.8 billion and the yields of CFL are 4.43 billion. In 2010, the national production of HID lamp is 174 million, of which high pressure mercury lamp production is 56 million, high pressure sodium lamp production is 54 million, and metal halide lamp production is 63 million. At the same time, China’s lighting consumption is mainly provided by the domestic production enterprises, andthe imported products accounted for less than 5% in the domestic consumer market. Nearly 70% of domestic production is for export. A good lighting industrial basewill not only provide a reliable supply of products in domestic market of LED lighting, but also provides a very good support of promoting cost performance of LED through scale effect.

(3) Government support policies

From a policy perspective, the State supports the LED lighting industry development through establishing the engineering research of national semiconductor lightingand industry alliance, introduce related financial support measures, policies and regulations and other means. Through fiscal subsidy way, the yields of efficient lighting products will be more than 150 million. In order to make the policy benefit more residents in rural areas, it is clearly demanded that the promotion proportion is not less than 30% of the total in this year. In addition, China will also produce hold the LED street lamps, landscape lighting and large billboard projects, which are needed in large-scale activities. These will have a great inspiration for LED industry prospects.

With the development of economy and technology, it is believed that LED will be more and more popular.For more information, please visit our website:http://www.analogtechnologies.com/product-LED-Related-Products.html

Super Resistor Kits

I am a designer. I have never used such a wonderful product. It is called RESISTOR KITS. It has 128 kinds of values from 0 ohm to 10M ohm in a box. The kits are very useful. It is easy to find any value of resister in E24 and I can place them on the work bench or the shelf. When I am doing an experiment, I only need to open the box and choose the label printed in the cover. Please look at the pictures below. Another reason I like it is the precision. It is 1%, much better than 5%.

This product is from Analog Technologies. A company which is founded in 1997, The main product lines include: laser drivers, TEC (Thermo-Electric Cooler) controllers, TECs (Thermo-Electric Coolers), high precision and high stability thermistors, customized heat sinks, SMT (SMD) resistor kits, SMT (SMD) capacitor kits, SMT (SMD) inductor kits, LED drivers, LED lights, etc.
I want to recommend this product to all of you. I hope you can like it.

For more information, please visit our website:http://www.analogtechnologies.com/resistorkits.html

Introduction to Heat Sinks

Heat sinks are a device which is used to dissipate heat of electronic elements in electrical appliances. There are many kinds of heat sink materials. The following describes are about the aluminum, copper and combinative radiation fins of copper and aluminum.
(1)Aluminum heat sink
Currently, heat sink of aluminum is one of heat sinks of the highest use rate. As the highest amount of metal in the earth’s crust, the main characteristics are low cost and low thermal capacity. Although the endothermic speed is very slow, the exothermic speed is fast. The effect of heat dissipation is proportion to its structure and work. If the number of heat sinks is more and the bottom polishing is better, the heat radiating effect will be better. However, it is also restricted by the manufacturing process because using manufacturing technology of extrusion aluminum, the minimum interval of radiator groove is only 1.1mm. The heat dissipation principle of aluminum heat sink is very simple: By using cooling fins to increasing the contact area with air and then using fans to accelerate the air flow, the heat from the fins will be taken away. The price of the heat sink is low. But compared with the following heat sinks, the cooling effect is very bad.

  

    (2)Copper heat sink
The material of heat sink is copper, which is the only difference with aluminum heat sink. The heat conduction efficiency of copper is 412w/mk, which is twice more than aluminum’s. But copper heat capacity is so high that the heat sink absorbs heat fast and release heat slowly. To achieve the ideal cooling effect, high power and high speed fans are needed. As the copper has good toughness and its manufacturing process is easier than aluminum, heat sink precision can be made higher and radiating area is correspondingly greater than the aluminum. All of these can make up for deficiency of heat slowly caused by its high heat capacity. Overall, its heat dissipation effect is much better than the aluminum but the cost is very high.

    (3)Aluminum heat sink inlaid with copper
Aluminum heat sink inlaid with copper use advantages of copper and aluminum. In touch with copper, the heat of the CPU is dissipated by using the characteristic of fast heat absorption of copper. And using fast exothermic characteristic of aluminum, the heat of copper is released. The radiating effect is better than the method of single pure copper or pure aluminum fins. However the drawback is that copper and aluminum can’t do 100% contact, the heat conduction efficiency will be affected to a certain extent.

For more information, please visit our website:http://www.analogtechnologies.com/Heat_sink.html

The Application Scope of LED

Because of LED’s advantages, LED is mainly used in the following aspects currently:

(1)LED is used in display screens and traffic signal lamps because LED lamps have characteristics of anti-seismic, impact resistance, fast speed of light response, electricity saving and long service life. LED has been widely used in various indoor and outdoor display screens, which can be divided into panchromatic, tri color and monochrome display screen. Traffic lights mainly use red, green and yellow LED of ultra-high brightness. As signal lamps of LED have advantages of energy saving and high reliability, LED market demand is very big in the national scope.

(2)In the automobile industry, automobile LED lamps include car interior lamps of aninstrument panel, a sound indicating lamp, back light of switches and reading lamps. And automobile LED lamps also include car external lamps of brake lights, tail lights, side lights and head lamps. If car lamps use incandescent lamps which are not impact resistance and easy damage, the lamps will often need to be replaced. Because LED has fast response speed, it can alert the driver brakes as early as possible and reduce the rear end accidents.

(3)Nowadays, the efficient side emitting of LED back light becomes the center of attention. As a LCD backlight application, LED has the advantages of long service life, high luminous efficiency, no interference and high performance price ratio. LED has been widely used in electronic watches, mobile phone, BP machine, electronic calculators and card reading machine. With the increasing miniaturization of portable electronic products, the advantages of LED backlight source are more and more obvious. Then the backlight production technology can develop toward more thin direction and low power consumption direction.

(4)In other applications, children’s flash shoes are very popular. When walking, the built-in LED will flash light. Because of the novel shape, the rich colors, not brittle breaking and low usage safety, LED Christmas lights are also becoming more and more popular.

For more information, please visit our website:http://www.analogtechnologies.com/product-LED-Related-Products.html

Temperature Control

Each one has its specific temperature. For example, my temperature is 36.5℃. If my temperature changes more than 0.1℃, I will get sick. Just like people, laser also has the specific temperature when it is working. If the temperature of laser changes more than 0.1℃, it will not work normally, and we cannot get the result what we would like to have. So we need to control the laser’s temperature seriously. We offer you the best devices to control the laser temperature.

The following picture is a physical figure of our temperature controller.

For more information, please visit our website:http://www.analogtechnologies.com/tec-controller.html

The design of all heat sinks of LED lighting lamps(2)

There are many kinds of heat sinks. In the view of manufacture, air cooled heat sinks can be divided into nano imprint lithography fins, extrusion heat sinks, casting heat sinks, folding heat sinks, improved casting heat sinks, forging heat sinks, cutting heat sinks, mechanical processing heat sinks and so on.
The size and thickness of heat sinks can directly affect the effective radiating area and heal removal capability. Good heat sinks should be greater than the contact surface, and have a radiating area as much as possible. The materials of the heat dissipation pad are also a kind of excellent materials. It combined with heat sinks can improve the heat radiating effect. Envelope volume refers to the volume occupied by heat sinks. If the heating power is large, the required heat sink area will be big. The preliminary design of heat sinks is based on envelope volume, and then the detail design will be considered. Heating wattage and envelope volume have the following formula:
LogV=1.4*logW-0.8(Min 1.5cm3)
In order to increase the fin efficiency which has a great influence on the thickness of the bottom of heat sinks, the bottom must be thick enough to make the hot transfer to all fins smoothly. And that can make all fins have the best utilization efficiency. If the bottom is too thick, it can cause the waste of materials and the heat accumulation, and also can reduce the heat conducting ability. The good design of the bottom thickness demand that the thickness of the heat source part should become thin in the part of edge. So it can make heat sink absorb enough heat by the heat source part and then it can quickly transfer the heat to the surrounding part. Radiating wattage and the thickness of the bottom have the following formula: t=7*logW-6(Min, 2mm)
The heat sink surface which is took acid aluminum processing, can increase the heat radiation performance and also increase the heat radiation effect. In general, exterior color is white or black. Convex surface can increase the heat dissipation area, but in the natural convection suasion, it may block the air flow and reduce the efficiency.
The above design is for your reference only. The actual heat sink design needs to consider the device and environment cooperation. Especially the design of high performance heat sink is required with the experimental proof and computer simulation. At present, the heat sink design has tended to limit, and air cooling mode can meet the requirements of the heat dissipation of high power LED. So the heat sink design should combine with characteristics of the power numbers of the LED, and that can make the design more diversified. In any case, the heat sinks are still the most common way of radiating. *The good design of heat sinks can improve the LED.For more information, please visit our website:http://www.analogtechnologies.com/product-LED-Related-Products.html

The characteristic analysis of LED heat dissipation substrate(1)

As the active area of the LED chip is small and its working current is big, the operating temperature of the LED ship can increase in a short time. The rise of pn junction temperature of LED can make the optical output power decrease, accelerate the aging of a chip, and shorten the service life of the device. With the rise in junction temperature, the LED wavelength will have “red shift”. (The drift visual effect of the orange and amber LED is more obvious). So in view of adverse effects of color drift in the practical application, the thermal design will limit the highest junction temperature. In the high power LED cooling channel, the heat radiating substrate is the key link between internal and external cooling channel. It has the following functions at least.
(1)A cooling channel of the LED chip.
(2)An electrical connection sub state of the LED chip.
(3)A physical support of the LED chip.
Substrate materials of the high power LED must meet requirements of the high insulating property, high stability, high thermal conductivity, and also have similar coefficients of thermal expansion, smoothness and high strength with chips.
The traditional materials of heat sinks are aluminum alloy or copper. Aluminum thermal conductivity can reach 209w/m.k, and aluminum has good processing characteristics and low cost. So it is widely used. Copper thermal conductivity can reach 390w/m.k, and it increases by 70% compared with aluminum. But the disadvantage is that its weight is about three times as much as aluminum and it has bad processing characteristics.
However, when applications are limited to the conduction characteristics as focus, the copper is used usually. In addition to the two kinds of materials, the increasing radiating materials are high-profile, such as compound materials based on carbon, metal powder sintered material, combined diamond, graphite, etc. aspic is the most new materials at present. It consists of many kinds of aluminum alloy and has special physical properties like control of thermal expansion properties, high conductivity and significant strength. Because of the cost, these new materials are used in the bottom of the power module and the substrate which is directly connected with chips.For more information, please visit our website:http://www.analogtechnologies.com/product-LED-Related-Products.html