1 Introduction LED is a type of light-emitting device that can directly convert electrical energy into visible light and radiant energy. It has low working voltage, low power consumption, high luminous efficiency, extremely short luminous response time, pure light color, firm structure, impact resistance and vibration resistance. , A series of characteristics of stable and reliable performance, light weight, small size, low cost, etc., the development is rapid, and can now mass produce high-brightness, high-performance products of various colors in the entire visible spectrum. The production of domestic red, green, orange, and yellow LEDs accounts for about 12% of the world's total. The industrial goal during the "Tenth Five-Year Plan" period is to reach an annual output of 30 billion pieces, and to achieve ultra-high brightness AiGslnP LED epitaxial wafers and chips. Large-scale production, with an annual output of more than 1 billion red, orange, and yellow ultra-high-brightness LED dies, breaking through the key technology of GaN materials and realizing the mass production of blue, green, and white LEDs. It is predicted that by 2005, the international LED market demand will be about 200 billion, with sales of 80 billion US dollars. In the LED industry link, the upstream is the production of LED substrate wafers and substrates. The industrialization of the midstream is LED chip design and manufacturing. The downstream is LED packaging and testing. The development of low thermal resistance, excellent optical characteristics, and highly reliable packaging technology is The new LED is a necessary way for industrialization to be practical and to the market. In a sense, it is the link between the industry and the market. Only when it is packaged can it become a terminal product, can it be put into practical use, and can it provide services to customers. The industrial chains are interlocking and seamless. 2 Particularity of LED package LED packaging technology is mostly developed and evolved on the basis of discrete device packaging technology, but it has great specificity. In general, the dies of discrete devices are sealed in the package body, and the role of the package is mainly to protect the dies and complete the electrical interconnection. The LED package is to complete the output of electrical signals, protect the normal work of the die, and output: the function of visible light, which has both electrical parameters and optical parameter design and technical requirements. It is not easy to use discrete device packages for LEDs. The core light-emitting part of the LED is a pn junction die composed of p-type and n-type semiconductors. When the minority carrier injected into the pn junction recombines with the majority carrier, it will emit visible light, ultraviolet light or near infrared light. However, the photons emitted by the pn junction area are non-directional, that is, they have the same probability of being emitted in all directions. Therefore, not all light generated by the die can be released, which mainly depends on the quality of the semiconductor material, the die structure and the geometry 〠Encapsulate the internal structure and encapsulation material, and the application requires to improve the internal and external quantum efficiency of the LED. The conventional Φ5mm LED package is to bond or sinter a square die with a side length of 0.25mm to the lead frame. The positive electrode of the die is connected to the gold wire through the spherical contact, and the inner lead is bonded to a pin, and the negative electrode is reflected. The cup is connected to the other pin of the lead frame, and then its top is encapsulated with epoxy resin. The function of the reflective cup is to collect the light emitted from the side and interface of the die and emit it in the desired direction angle. The epoxy resin encapsulated at the top is made into a certain shape, which has several functions: protects the die and the like from external erosion; adopts different shapes and material properties (with or without dispersing agent) to act as a lens or a diffuse lens Function, control the divergence angle of light; the refractive index of the die is too related to the refractive index of air, so that the critical angle of total reflection inside the die is very small. Only a small part of the light generated by its active layer is taken out, and most of it is easy to The inside of the core is absorbed by multiple reflections, and total reflection is prone to cause excessive light loss. The epoxy resin of the corresponding refractive index is used as a transition to improve the light exit efficiency of the die. The epoxy resin used to form the shell must have moisture resistance, insulation, mechanical strength, high refractive index and transmittance to the core. Choose different encapsulation materials with different refractive index. The effect of encapsulation geometry on photon escape efficiency is different. The angular distribution of luminous intensity is also related to the die structure, light output method, and the material and shape of the encapsulation lens. If a sharp resin lens is used, the light can be concentrated in the direction of the axis of the LED, and the corresponding viewing angle is small; if the resin lens on the top is round or planar, the corresponding viewing angle will increase. Under normal circumstances, the luminous wavelength of the LED varies with temperature from 0.2 to 0.3 nm / ℃, and the spectral width increases accordingly, which affects the vividness of the color. In addition, when the forward current flows through the pn junction, the heat loss causes a temperature rise in the junction area. When the temperature rises by 1 ° C near the room temperature, the luminous intensity of the LED will be reduced by about 1% accordingly, and the package will dissipate heat; The purity and luminous intensity are very important. In the past, the method of reducing its driving current was used to reduce the junction temperature. The driving current of most LEDs is limited to about 20mA. However, the light output of LEDs will increase with the increase of current. At present, the driving current of many power LEDs can reach 70mA, 100mA or even 1A. It is necessary to improve the packaging structure. The new LED packaging design concept and low thermal resistance packaging structure and Technology to improve thermal characteristics. For example, a large-area chip flip structure is adopted, silver paste with good thermal conductivity is selected to increase the surface area of ​​the metal bracket, and the silicon carrier of the solder bump is directly mounted on the heat sink. In addition, in the application design, the thermal design and thermal conductivity of PCB circuit boards are also very important. After entering the 21st century, LED's high efficiency, ultra-high brightness, and full color have been continuously developed. The light efficiency of red and orange LEDs has reached 100Im / W, green LEDs are 501m / W, and the luminous flux of a single LED has also reached tens Im. LED chips and packaging no longer follow Gong's traditional design concepts and manufacturing production modes. In terms of increasing the light output of the chip, research and development is not limited to changing the amount of impurities in the material, lattice defects and dislocations to improve internal efficiency. At the same time, how to improve The internal structure of the die and the package enhances the chance of photon emission inside the LED, improves the light efficiency, solves the heat dissipation, optimizes the design of light extraction and heat sink, improves the optical performance, and accelerates the surface mount SMD process. . 3 Product packaging structure type Since the 1990s, many breakthroughs have been made in the research and development of LED chip and material manufacturing technology, transparent substrate trapezoidal structure, textured surface structure, chip flip structure, commercialized ultra-high brightness (above 1cd) red, orange, Yellow, green, and blue LED products have been asked to the market one after another. As shown in Table 1, they have been used in special lighting with low and medium luminous flux since 2000. The upstream and midstream industries of LED have received unprecedented attention, and further promote the development of downstream packaging technology and industry. The use of different packaging structures and sizes, different luminescent color dies and their two-color or three-color combinations can produce a variety of Series, variety, specification products. The type of LED product packaging structure is shown in Table 2, and it is also classified according to the characteristics of the light color, chip material, light brightness, size, etc. A single die generally constitutes a point light source, and the assembly of multiple die generally constitutes a surface light source and a line light source, which are used for information, status indication and display. The light-emitting display also uses multiple die, through the proper connection of the die (including series and (Parallel) combined with a suitable optical structure to form the light-emitting segment and light-emitting point of the light-emitting display. Surface-mount LEDs can gradually replace pin-type LEDs, and the application design is more flexible. It has occupied a certain share in the LED display market and has accelerated development trends. Some products of solid-state lighting sources are on the market, which will become the medium- and long-term development direction of LEDs in the future. 4 pin package The LED foot package uses lead frames as the pins for various package appearances. It is the first package structure successfully developed and put on the market. It has a large number of varieties and a high degree of technical maturity. The structure and reflection layer in the package are still constantly improving. Standard LEDs are considered by most customers to be the most convenient and economical solution in the display industry. Typical traditional LEDs are housed in an enclosure that can withstand an input power of 0.1W. 90% of the heat is generated by the negative pole The rack is distributed to the PCB and then to the air. How to reduce the temperature rise of the pn junction during operation is a must for packaging and application. The encapsulation material mostly uses high temperature curing epoxy resin, which has excellent optical properties, good process adaptability, and high product reliability. It can be made into colored transparent or colorless transparent and colored scattering or colorless scattering lens packages, different lens shapes Various shapes and sizes are formed. For example, a circle is divided into several types such as Φ2mm, Φ3mm, Φ4.4mm, Φ5mm, and Φ7mm according to the diameter. Different components of epoxy resin can produce different luminous effects. The color point light source has a variety of different packaging structures: the ceramic base epoxy resin package has better operating temperature performance, the pins can be bent into the desired shape, and the volume is small; the metal base plastic reflector package is an energy-saving indicator , Suitable for power supply indication; flashing package of CMOS oscillator circuit chip and LED die, which can generate a strong visual impact of flashing light; two-color type is composed of two different luminous color dies, encapsulated in the same epoxy In the resin lens, the third mixed color can be obtained in addition to the double color. It is widely used in large-screen display systems and can be packaged to form a double color display device; the voltage type combines the constant current source chip and the LED die. Can directly replace various voltage indicators of 5-24V. The surface light source is formed by bonding a plurality of LED dies to the specified positions of the micro PCB board, using a plastic reflective frame cover and encapsulating epoxy resin. Different designs of the PCB board determine the arrangement and connection method of the outer leads. Structures such as insertion and single in-line insertion. Point and surface light sources have developed hundreds of package shapes and sizes for the market and customers. LED light-emitting display can be composed of digital tube, rice tube, symbol tube, rectangular tube, and various multi-bit products, which are designed into various shapes and structures according to actual needs. Take the nixie tube as an example, there are three kinds of packaging structures such as reflector, monolithic integrated, and single seven-segment type. There are two kinds of connection methods: common anode and common cathode. One bit is usually called the nixie tube, and two or more Generally called a display. The reflector type has the characteristics of large font, material saving, and flexible assembly. It is generally made of white plastic into a seven-segment shell with a reflective cavity, and a single LED die is bonded to the seven reflective cavities with the reflective cover On the PCB boards that are aligned with each other, the center of the bottom of each reflective cavity is the light-emitting area formed by the die. The wires are bonded by pressure welding, epoxy resin is dropped in the reflective cover, and the PCB board with the die is glued. Alignment bonding, and then cured. The reflector type is divided into two types: air seal and actual seal. The former uses epoxy resin with a scattering agent and a dye, which is mostly used for unit and double-position devices; the latter is covered with a color filter and a uniform light film, and is connected to the die The bottom plate is coated with transparent insulating glue to improve light output efficiency, and is generally used for digital display with more than four digits. The monolithic integrated type is to produce a large number of seven-segment digital display graphics dies on a luminescent material wafer, and then scribe and divide into single-chip graphics dies, bonding, pressure welding, and encapsulating the shell with lenses (commonly known as fish-eye lenses). A single seven-segment type divides the fabricated large-area LED chip into a light-emitting strip containing one or more dies, so the same seven strips are bonded to the digital font's Kovar frame, after pressure welding, epoxy Resin package structure. The monolithic and monolithic features are miniaturized and can be used in dual in-line packages, most of which are dedicated products. The LED light column display is equipped with 101 dies (up to 201 dies) on a circuit board with a length of 106mm. It is a high-density package. Using the principle of optical refraction, the point light source is imaged through the 13-15 gratings of the transparent cover. To complete the display of each die from point to line, the packaging technology is more complicated. The electroluminescence mechanism of the semiconductor pn junction determines that the LED cannot produce white light with a continuous spectrum. At the same time, it is impossible for a single LED to produce more than two types of high-brightness monochromatic light. Only fluorescent materials, blue or ultraviolet LEDs can be used during packaging The phosphor is coated on the die to indirectly generate a broadband spectrum and synthesize white light; or several (two or three or more) dies emitting different colors are packaged in a component housing, and the white LED is formed by the mixture of colored lights . Both of these methods have been put into practical use. In 2000, Japan produced 100 million white LEDs, developed into a class of products that stably emit white light, and designed and assembled multiple white LEDs to have low luminous flux requirements. Lord, pursue the trendy electric light source. 5 Surface mount package In 2002, surface-mount packaged LEDs (SMD LEDs) were gradually accepted by the market and gained a certain market share. The shift from leaded packages to SMD is in line with the development trend of the entire electronics industry. Many manufacturers have introduced such products. The early SMD LEDs mostly used the SOT-23 improved type with transparent plastic body, the overall size was 3.04 & TImes; 1.11mm, and the reel-type container was taped and packed. Based on SOT-23, the SLM-125 series of high-brightness SMD with lenses and the SLM-245 series of LEDs were developed. The former is monochromatic, and the latter is bicolor or tricolor. In recent years, SMD LED has become a hot spot for development, which has solved the problems of brightness, viewing angle, flatness, reliability, consistency and so on. It adopts lighter PCB board and reflective layer materials. Less oxygen resin, and remove the heavier carbon steel material pins, by reducing the size and weight, you can easily reduce the weight of the product by half, and finally make the application more perfect, especially suitable for indoor, semi-outdoor full-color display application. The pad is an important channel for its heat dissipation. The SMD LED data provided by the manufacturer are based on the 4.0 & TImes; 4.0mm pad. The pad can be designed to be equal to the pin by reflow soldering. Ultra-high-brightness LED products can be packaged with PLCC (plastic packaged leaded chip carrier) -2, the overall size is 3.0 & TImes; 2.8mm, the high-brightness die is assembled by a unique method, and the thermal resistance of the product is 400K / W. CECC welding, its luminous intensity reaches 1250mcd under 50mA drive current. The character height of the seven-segment one-digit, two-digit, three-digit and four-digit SMD LED display devices is 5.08-12.7mm, and the display size can be selected from a wide range. The PLCC package avoids the manual insertion and pin alignment process required for the seven-segment digital display of the pin, and meets the production requirements of the automatic pick-and-place equipment. The application design space is flexible and the display is bright and clear. The multi-color PLCC package has an external reflector, which can be easily combined with a light emitting tube or light guide. The reflective type replaces the current transmissive optical design to provide uniform illumination for a large area. The research and development is driven at 3.5V, 1A Power SMD LED package working under conditions. 6 Power package LED chips and packages are developing towards high power, and generate luminous fluxes that are 10-20 times larger than Φ5mm LEDs under high current. Effective heat dissipation and non-degradable packaging materials must be used to solve the problem of light attenuation. Therefore, the package and packaging are also the key Technology, LED packages that can withstand several W power have appeared. The 5W series of white, green, blue green and blue power LEDs have been available since the beginning of 2003. The white LED has a light output of 1871m and a light efficiency of 44.31m / W. The problem of green light attenuation has been developed. It has developed LEDs that can withstand 10W power. Area tube; Dagger size is 2.5 & TImes; 2.5mm, can work under 5A current, and the light output reaches 2001m, which has great room for development as a solid lighting source. Luxeon series power LED is to flip-chip solder A1GalnN power type flip-chip on silicon carrier with solder bumps, then put the silicon carrier that has been flip-chip soldered into the heat sink and the shell, and bond the wire to encapsulate. This package is the best for the design of light extraction efficiency, heat dissipation performance, and increased operating current density. Its main features: low thermal resistance, generally only 14 ℃ / W, only 1/10 of conventional LEDs; high reliability, filled with stable flexible gel inside the package, in the range of -40-120 ℃, will not be affected by temperature The internal stress generated by the sudden change disconnects the gold wire from the lead frame and prevents the epoxy lens from turning yellow, and the lead frame will not be contaminated by oxidation; the optimal design of the reflective cup and lens makes the radiation pattern controllable and optical The most efficient. In addition, its output optical power, external quantum efficiency and other properties are excellent, and the LED solid light source has been developed to a new level. The packaging structure of Norlux series power LEDs is a multi-chip combination with hexagonal aluminum plate as the base (making it non-conductive). The base diameter is 31.75mm, the light-emitting area is located at the center of it, and the diameter is about (0.375 × 25.4) mm, which can accommodate 40 LED die, aluminum plate as heat sink at the same time. The bonding wires of the die are connected to the positive and negative electrodes through the two contact points made on the base, and the number of arranged dies on the base is determined according to the required output optical power. The ultra-high brightness AlGaInN and AlGaInP of the package can be combined The die, whose emitted light is monochromatic, color or synthetic white, respectively, is finally encapsulated with a high refractive index material according to the optical design shape. This kind of package adopts the conventional high-density combination package of the die, which has high light extraction efficiency and low thermal resistance, and better protects the die and the bonding wire. It has a higher optical output power under high current and is also a promising prospect. LED solid light source. In application, the packaged product can be assembled on a metal core PCB board with an aluminum sandwich to form a power density LED. The PCB board is used for wiring of device electrode connections. The aluminum core sandwich can be used as a heat sink to obtain Higher luminous flux and photoelectric conversion efficiency. In addition, the packaged SMD LEDs are small in size and can be flexibly combined to form a variety of colorful light sources such as module type, light guide plate type, condensing type, and reflective type. The thermal characteristics of power LEDs directly affect the operating temperature, luminous efficiency, luminous wavelength, and service life of LEDs. Therefore, the packaging design and manufacturing technology of power LED chips are even more important. 7 LED development and application prospects In recent years, the luminous efficiency of LEDs has increased by 100 times, and the cost has dropped by 10 times. It is widely used in large-area graphic display full-color screens, status indicators, sign lighting, signal displays, LCD backlights, automobile combination tail lights and interior lighting In other aspects, its development prospects have attracted major global lighting manufacturers to join LED light sources and market development. White light LEDs with great development and application prospects are used as solid lighting devices, which are economically significant, and are environmentally friendly. They are gradually replacing traditional incandescent lamps. The world's annual growth rate is more than 20%. The United States, Japan, Europe and Taiwan The province has launched a semiconductor lighting plan. At present, the luminous efficiency of ordinary white LEDs is 251m / W, and experts predict that it may exceed 3001m / W in 2005. The excellent heat dissipation and optical characteristics of power LEDs are more suitable for the field of general lighting, and are considered by the academic and industrial circles as the only way for LEDs to enter the lighting market. To replace fluorescent lamps, white LEDs must have a light efficiency of 150-2001m / W, and the price per Im should be significantly lower than 0.015 / Im (the current price is about 0.25 $ / Im, and the red LED is 0.065 / Im) To achieve this goal, there are still many technical problems that need to be studied, but overcoming these problems is not very far away. According to the principles of solid-state luminescence physics, the luminous efficiency of LEDs can be approximately 100%. Therefore, LEDs are known as new light sources in the 21st century, and are expected to become the fourth generation light sources after incandescent lamps, fluorescent lamps, and high-intensity gas discharge lamps. 8 Conclusion There are more than 20 R & D and production units in the domestic LED industry and more than 150 back-end packaging companies in the domestic LED industry. High-end packaging products have not yet been brought to market. At present, we have completed the industrialization research of GaN-based blue-green LED midstream process technology, and strive to achieve the performance index of products in the short term to reach the level of similar foreign products in the same period. New products such as power LED chips for lighting sources. The Ministry of Science and Technology will invest 80 million yuan to start the national semiconductor lighting project, pay attention to terminal products, start with special products, and use automotive and urban landscape lighting as a market breakthrough, placing high-power, high-brightness LEDs in a prominent position. The results will serve the Beijing Olympics and Shanghai World Expo. There is no doubt that substrates, epitaxy, chips, packaging, and applications in the industrial chain need to develop together, and multi-party interactive cultivation. Packaging is a part of the industry chain that needs attention and attention.
Gaming Headset With Microphone/Good Gaming Headset with mic for pc/Gaming Headset Pc
Features:
1. Popular gaming headset with custom logo color
2. Manufacture with competitive price & good quality
4. Excellent sound performance
5. Custom packing design service
6. Samples are available
7. Headphone for personal use, for gift to friends
Gaming Headset With Microphone Gaming Headset With Microphone,Gaming Headset Pc,Ps4 Headset,Childrens Headphones With Microphone Shenzhen Greater Industry Co., Ltd. , https://www.szgreater.net
