LED guardrail lamp diode package structure and technology

Table 3 shows several dimensions of common SMD LEDs, as well as the best viewing distance calculated from the dimensions (plus the necessary clearance). The pad is an important channel for heat dissipation. The SMD LED data provided by the manufacturer is based on a 4.0×4.0mm pad. The reflow soldering can be used to design the pad to be equal to the pin. Ultra-high-brightness LED products can be packaged in PLCC (plastic package with lead chip carrier)-2, the external dimensions are 3.0×2.8mm, and the high-brightness die is assembled by a unique method. The thermal resistance of the product is 400K/W, which can be pressed. CECC soldering, its luminous intensity is 1250mcd at 50mA driving current. The seven-segment one, two, three and four digital SMD LED display devices have a character height of 5.08-12.7mm and a wide display size range. The PLCC package avoids the manual insertion and pin alignment processes required for the seven-segment digital display of the pin, and meets the production requirements of the automatic pick-and-place device. The application design space is flexible and the display is bright and clear. The multi-color PLCC package features an external reflector that can be easily combined with an LED or light guide to replace the current transmissive optical design with a reflective version to provide uniform illumination over a wide area, developed at 3.5V, 1A drive Power SMD LED package operating under conditions.

6 power package

The LED chip and package are developed in the direction of high power. Under the high current, the luminous flux is 10-20 times larger than that of the Φ5mm LED. The effective heat dissipation and non-degraded packaging materials must be used to solve the light decay problem. Therefore, the package and the package are also the key. Technology, LED packages that can withstand several W power have emerged. 5W series white, green, blue green, blue power LEDs have been available since the beginning of 2003. The white LED light output reaches 1871m, the light efficiency is 44.31m/W green light decay problem, and the LED that can withstand 10W power is developed. The area tube; the size of the crucible is 2.5×2.5mm, it can work under the current of 5A, and the light output reaches 2001m. It has great development space as a solid illumination source.

The Luxeon series power LEDs are flip-chip soldered to the silicon carrier with solder bumps, and then the flip-chip soldered silicon carrier is placed in the heat sink and the package, and the bonding leads are packaged. This package is optimized for light extraction efficiency, heat dissipation performance, and increased operating current density. Its main features: low thermal resistance, generally only 14 ° C / W, only 1 / 10 of conventional LED; high reliability, flexible gel filled inside the package, in the range of -40-120 ° C, not due to temperature The internal stress generated by the sudden change breaks the gold wire from the lead frame and prevents the epoxy lens from turning yellow, and the lead frame is not stained 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 package structure of the Norlux series of power LEDs is a multi-chip combination of a hexagonal aluminum plate as a base (which makes it non-conductive). The base has a diameter of 31.75mm, and the light-emitting area is located at the center thereof. The diameter is about 0.375×25.4 mm and can accommodate 40. Only the LED die, the aluminum plate acts as a heat sink at the same time. The bonding wires of the die are connected to the positive and negative electrodes through two contact points made on the base, and the number of aligned dies on the base is determined according to the required output optical power, and the packaged ultra-high brightness AlGaInN and AlGaInP can be combined. The die, which emits light in a single color, color or synthetic white, is finally encapsulated in an optically designed shape with a high refractive index material. The package adopts a conventional high-density package with high density, high light extraction efficiency, low thermal resistance, better protection of the die and bonding wires, and high light output power under high current, which is also a promising future. LED solid light source.

In the application, the packaged product can be assembled on a metal core PCB board with aluminum interlayer to form a power density LED. The PCB board is used as the wiring for connecting the device electrodes, and the aluminum core interlayer can be used as a heat sink. 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 illumination sources such as module type, light guide type, concentrating type, and reflective type.

The thermal characteristics of power LEDs directly affect the operating temperature, luminous efficiency, wavelength of illumination, and lifetime of LEDs. Therefore, the packaging design and manufacturing technology of power LED chips are particularly important.

7 LED Development and Application Prospects Table 3 shows several dimensions of common SMD LEDs, as well as the optimal viewing distance calculated from the dimensions (plus the necessary clearances). The pad is an important channel for heat dissipation. The SMD LED data provided by the manufacturer is based on a 4.0×4.0mm pad. The reflow soldering can be used to design the pad to be equal to the pin. Ultra-high-brightness LED products can be packaged in PLCC (plastic package with lead chip carrier)-2, the external dimensions are 3.0×2.8mm, and the high-brightness die is assembled by a unique method. The thermal resistance of the product is 400K/W, which can be pressed. CECC soldering, its luminous intensity is 1250mcd at 50mA driving current. The seven-segment one, two, three and four digital SMD LED display devices have a character height of 5.08-12.7mm and a wide display size range. The PLCC package avoids the manual insertion and pin alignment processes required for the seven-segment digital display of the pin, and meets the production requirements of the automatic pick-and-place device. The application design space is flexible and the display is bright and clear. The multi-color PLCC package features an external reflector that can be easily combined with an LED or light guide to replace the current transmissive optical design with a reflective version to provide uniform illumination over a wide area, developed at 3.5V, 1A drive Power SMD LED package operating under conditions.
6 power package
The LED chip and package are developed in the direction of high power. Under the high current, the luminous flux is 10-20 times larger than that of the Φ5mm LED. The effective heat dissipation and non-degraded packaging materials must be used to solve the light decay problem. Therefore, the package and the package are also the key. Technology, LED packages that can withstand several W power have emerged. 5W series white, green, blue green, blue power LEDs have been available since the beginning of 2003. The white LED light output reaches 1871m, the light efficiency is 44.31m/W green light decay problem, and the LED that can withstand 10W power is developed. The area tube; the size of the crucible is 2.5×2.5mm, it can work under the current of 5A, and the light output reaches 2001m. It has great development space as a solid illumination source.
The Luxeon series power LEDs are flip-chip soldered to the silicon carrier with solder bumps, and then the flip-chip soldered silicon carrier is placed in the heat sink and the package, and the bonding leads are packaged. This package is optimized for light extraction efficiency, heat dissipation performance, and increased operating current density. Its main features: low thermal resistance, generally only 14 ° C / W, only 1 / 10 of conventional LED; high reliability, flexible gel filled inside the package, in the range of -40-120 ° C, not due to temperature The internal stress generated by the sudden change breaks the gold wire from the lead frame and prevents the epoxy lens from turning yellow, and the lead frame is not stained 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 package structure of the Norlux series of power LEDs is a multi-chip combination of a hexagonal aluminum plate as a base (which makes it non-conductive). The base has a diameter of 31.75 mm, and the light-emitting area is located at the center thereof, and the diameter is about 0.375 × 25.4 mm. 40 LED dies, the aluminum plate acts as a heat sink at the same time. The bonding wires of the die are connected to the positive and negative electrodes through two contact points made on the base, and the number of aligned dies on the base is determined according to the required output optical power, and the packaged ultra-high brightness AlGaInN and AlGaInP can be combined. The die, which emits light in a single color, color or synthetic white, is finally encapsulated in an optically designed shape with a high refractive index material. The package adopts a conventional high-density package with high density, high light extraction efficiency, low thermal resistance, better protection of the die and bonding wires, and high light output power under high current, which is also a promising future. LED solid light source.
In the application, the packaged product can be assembled on a metal core PCB board with aluminum interlayer to form a power density LED. The PCB board is used as the wiring for connecting the device electrodes, and the aluminum core interlayer can be used as a heat sink. 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 illumination sources such as module type, light guide type, concentrating type, and reflective type.
The thermal characteristics of power LEDs directly affect the operating temperature, luminous efficiency, wavelength of illumination, and lifetime of LEDs. Therefore, the packaging design and manufacturing technology of power LED chips are particularly important.

7 LED development and application prospects

In recent years, the luminous efficiency of LEDs has increased by 100 times and the cost has decreased by 10 times. It is widely used in large-area graphic display full-color screens, status indication, sign illumination, signal display, backlight of liquid crystal display, automobile combination taillights and interior lighting. In terms of other aspects, its development prospects have attracted global lighting manufacturers to join the LED light source and market development. The development and application prospects are white LEDs, which are economical for solid lighting devices and environmentally friendly. They are gradually replacing traditional incandescent lamps, with an annual growth rate of over 20% in the world, the United States, Japan, Europe and Taiwan. The province has launched a semiconductor lighting program. 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 characteristics and optical characteristics of power LEDs are more suitable for the general lighting field, and are considered by the academic community and the industry to be the only way for LEDs to enter the lighting market. In order to replace fluorescent lamps, white LEDs must have a luminous efficacy of 150-2001 m/W, and the price per Im should be significantly lower than 0.015/Im (current price is about 0.25$/Im, red LED is 0.065/Im) There are still many technical issues that need to be studied to achieve this goal, but it is not a long way to overcome these problems. According to the principle of solid-state luminescence, the luminous efficiency of LED can be approximately 100%. Therefore, LED is known as a new light source in the 21st century and is expected to become the fourth generation light source after incandescent lamps, fluorescent lamps and high-intensity discharge lamps.

8 Conclusion

There are more than 20 domestic and midstream research and production units and more than 150 downstream packaging companies in the domestic LED industry. High-end packaging products have not yet been introduced to the market. At present, the GaN-based blue-green LED midstream technology industrialization research has been completed, and the performance index of the products has reached the level of similar products in foreign countries in the short term, striving to achieve the monthly production capacity of 10 kk in a short period of time and develop white light. 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 the terminal products, start with special products, take the automobile and urban landscape lighting as the market breakthrough, and put the high-power and high-brightness LEDs in the prominent position. The results will serve the Beijing Olympics and the Shanghai World Expo. Undoubtedly, the substrate, epitaxy, chip, package and application in the industrial chain need to be developed together, and multi-party interactive cultivation. Packaging is the part of the industry chain, which needs attention and attention.

In recent years, the luminous efficiency of LEDs has increased by 100 times and the cost has decreased by 10 times. It is widely used in large-area graphic display full-color screens, status indication, sign illumination, signal display, backlight of liquid crystal display, automobile combination taillights and interior lighting. In terms of other aspects, its development prospects have attracted global lighting manufacturers to join the LED light source and market development. The development and application prospects are white LEDs, which are economical for solid lighting devices and environmentally friendly. They are gradually replacing traditional incandescent lamps, with an annual growth rate of over 20% in the world, the United States, Japan, Europe and Taiwan. The province has launched a semiconductor lighting program. 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 characteristics and optical characteristics of power LEDs are more suitable for the general lighting field, and are considered by the academic community and the industry to be the only way for LEDs to enter the lighting market. In order to replace fluorescent lamps, white LEDs must have a luminous efficacy of 150-2001 m/W, and the price per Im should be significantly lower than 0.015/Im (current price is about 0.25$/Im, red LED is 0.065/Im) There are still many technical issues that need to be studied to achieve this goal, but it is not a long way to overcome these problems. According to the principle of solid-state luminescence, the luminous efficiency of LED can be approximately 100%. Therefore, LED is known as a new light source in the 21st century and is expected to become the fourth generation light source after incandescent lamps, fluorescent lamps and high-intensity discharge lamps.