고전력 초 고휘도 LED 인쇄 회로 기판2020-06-02
고전력 초 고휘도 LED 인쇄 회로 기판
Recently, combined with the latest achievements in the field of LED lighting, interest in creating light sources based on powerful ultra-bright LEDs has increased dramatically. The luminous efficiency of semiconductor LED has reached 100lm/W. This ultra-high-brightness LED replaces the traditional incandescent lamp and is used in almost all areas of lighting technology: street lamps, automotive lighting, emergency lighting, advertising signs, LED panels, indicators, traffic lanes, traffic lights, etc. These LEDs have become an integral part of decorative lighting and dynamic systems due to their monochrome and switching speed. They can also be used in places where substantial energy savings are required,
Compared with traditional light sources, the main advantages of powerful ultra-bright LEDs are:
Long service life (tens of times or even hundreds of times longer than traditional incandescent bulbs), so the possibility of replacing burning bulbs is greatly reduced, which is especially important for hard-to-reach places;
Efficiency and high efficiency: under similar brightness, the energy consumption of LED lamps is 3-5 times less than halogen lamps or incandescent lamps;
Easy to install and compact: surface mount installation and small size LEDs allow developers and designers to choose interesting solutions to create lighting systems;
A wide range of choices for white, color and RGB LED shadows: allows you to use dynamic changes in color and brightness to realize interesting ideas for lighting or decorative lighting developers;
The low heat radiation of LED lamps allows you to install them in places where incandescent lamps cannot be used due to high heat.
Unlike traditional incandescent lamps, LEDs do not radiate heat to the surrounding space, but conduct heat in the direction of the transition from pn to the heat sink in the LED housing (usually the output of the LED or a special metal plate). Therefore, the heat removal process is more complicated and specific. The heat dissipation path is composed of many thermal resistors: “pn junction-heat sink of the housing”, “heat sink of the housing-a printed circuit board”, “a printed circuit board-heat sink”, “heat sink-environment”. As a result, the use of high-power LEDs is associated with a high probability of an excessive increase in transition temperature, which directly affects the life, reliability, and light characteristics of the LED.
Research data shows that about 65-85% of the electrical energy is converted into heat when the LED is working. However, depending on the thermal conditions recommended by the LED manufacturer, the life of the LED can be as long as 10 years. However, if you violate the thermal specifications (usually operating at a transition temperature exceeding 120 … 125°C), the life of the LED may be shortened by 10 times! And in the case of serious failure to meet the recommended thermal conditions, for example, when the LED of the emitter type is turned on for more than 5-7 seconds without a heat sink, the LED will fail even during the first turn-on process. In addition, the increase in the transition temperature causes the brightness of the glow to decrease and the operating wavelength to shift. Moreover, the polymer used to make the LED housing cannot be heated above a certain limit because the LED components (contacts, frame, crystal, lens material) have different linear expansion coefficients and may break the contact connection. Therefore, it is very important to calculate the thermal state correctly and dissipate the heat generated by the LED as much as possible.
사용되는 전원 LED가 0.5 와트 미만이면 PCB 수준 FR-4 인쇄 회로 기판을 조립하는 기존 LED를 사용할 수 있습니다. 그러나 더 높은 전력을 발산하는 경우 열전도도가 향상되고 열 저항이 0.45 ~ 1.5K / W 인 금속베이스와 유전체층이있는 특수 인쇄 회로 기판을 사용해야 할 수도 있습니다.
The main manufacturers of high-power LEDs, such as Cree, Osram, Nichia, Luxeon, Seoul Semiconductor, Edison Optoelectronics, etc., have long been simplified and enabled for the expansion of LED applications, in the form of LED modules, or In the printed cluster circuit board and x with metal base (international classification IMPCB-insulated metal printed circuit board, or AL PCB-aluminum printed circuit board s). LED clusters are off-the-shelf connector plates of various shapes (star, circular, linear, rectangular, hexagonal) and one or more LED bases, lens (collimator) can be installed, simple power supply Connection and easy installation. By soldering to the contact pads of the circuit board s mounted on the circuit board e connector, a cluster connection for powering the LED driver can be achieved. Such clusters sometimes contain both limiting resistors and the power driver itself, so they can be directly connected to low-voltage power supplies.
This type of cluster is used for the installation of non-standard luminaires, indoor and landscape lighting, and the creation of dynamic lighting shows-that is, you can arrange these size and shape LED clusters as elements of the LED matrix without increasing costs And place. But if the standard form is difficult or impossible to do-unsatisfactory size, LED or layout, then the spacing between the designs is customized yvaetsya, your personalized design printed circuit board trumpet-high-tech and adaptive lighting The best solution for the system.
If necessary, the cluster based on a printed circuit board with a metal base and the LEDs mounted thereon can be installed on an additional heat sink-the last link of the heat dissipation channel. The choice of the heat sink can be an aluminum heat sink or a metal shell of the product, depending on which part of the total budget of the thermal resistance “transition-environment” was “wasted” at the previous link of the thermal path.
소비 전력이 1W 인 LED (25 ° C에서 자연 대류가 복잡하지 않다고 가정)의 경우 보드를 사용해야하며 알루미늄베이스의 면적은 6.5cm2 이상이어야합니다. 영역 보드 크기는 대략 주어진 값에 해당하며 클러스터 장치에 추가 방열판이 필요하지 않은 경우 LED는 정격 작동 상태입니다. 밀폐 된 인클로저 및 주변 온도가 더 높은 환경에서 작업 할 때 추가 냉각 또는 추가 방열판 또는 증가 된 영역 보드 트럼펫이 필요하지 않습니다.
권장 작동 온도에서 LED 칩을 제공하기 위해 하부 기판 트럼펫은 다중 방열판-전도성 페이스트의 특수 플라스틱 혼합물을 통해 해당 유형에 해당하는 클러스터로 설정되거나 열 그리스로 채워질 때 호출되기 때문입니다. 시스템의 우수한 열 접촉 및 최대 열전도도를 제공합니다.
예를 들어 다른 방열판을 사용하는 경우 Cree XR-E LED가있는 클러스터의 전원 공급 장치 전류를 1A로 늘릴 수 있고, XP-E LED 클러스터의 전류를 700mA, XP-C, XR로 늘릴 수 있습니다. -C LED 클러스터의 전류가 500mA로 증가하여 광도가 약 70 % 증가합니다.
Let’s get entangled in the printed circuit board E for high-power LED clusters-printed circuit boards and metal bases. For example, in this type of board, a metal plate is used as the base, on which one or more conductive layers of copper foil Bond with glass fiber impregnated with resin (prepreg). This card trumpet is used in products in the entire area where there is a high local or distributed heat load. The simplest type of printed circuit board is small, so the most cost-effective LEDs for effective surface mounting are printed single-layer circuit boards and with aluminum bases. In essence, the circuit board a is a single-layer printed circuit board glued to an aluminum board. The generated heat easily passes through the insulator, and then quickly dissipates through the aluminum firmly attached heat sink formed as part of the printed circuit board s.
Circuit boards of ultra-high-brightness LEDs are usually covered with black or white solder resist layers, which further increase light absorption or light reflection, respectively, which beneficially affects the temperature conditions and the design of the lamp.
Briefly consider the materials used in the circuit board and x metal base:
Copper foil-copper foil with a thickness of 35-350 microns, is the standard for the production of printed circuit boards.
Dielectric-prepreg-glass fiber impregnated with epoxy resin with a thickness of 50-150 microns. As a prepreg, it can be used as a conventional epoxy glass fiber FR-4 and a special thermally conductive composition (T-preg) with optimal thermal and electrical insulation properties. It is a special chemical-resistant structure with a high thermal conductivity of 75-200μm and is made of a special dielectric-polymer and special ceramic mixture. The polymer is selected according to the dielectric properties of the polymer, and the ceramic filler is designed to increase thermal conductivity, so the material has excellent dielectric properties and very low thermal resistance. For example, the material of this layer Bond Ply Thermal Clad IMS (Bergquist) has a volume resistivity of at least 1014 ohm•cm. When the thickness of the dielectric layer is 75 μm, the allowable operating voltage between the layers is 5.5 kV AC or higher, and the thermal conductivity is not less than 1.3 W/mK, which is sufficient for most applications.
A circuit board with a metal base dielectric layer (copper core) and x are connected to a lower metal (aluminum or copper) core. The lower metal core serves as a heat sink for the entire printed circuit board s and plays from the upper layer to the lower layer (metal base) Thermal conductivity.
The main comparative characteristics of the dielectric are given in the table.
In the design of plates with metal bases, the coefficient of thermal expansion (CTE) of the substrate material plays an important role. The use of materials with large KTP at high temperatures can cause internal mechanical stress in the structure. Therefore, for high temperature applications where this parameter is critical, materials with low KTP low carbon steel substrates (thicknesses 1 and 2.3 mm) are used.
구리는 열전도율이 가장 좋지만 알루미늄은 저렴하고 중요하게 가볍기 때문에 금속 기판이있는 판재에 가장 일반적으로 사용되는 재료입니다.
폐 알루미늄 기판의 열전도율 :
알루미늄 1100 (HELL의 아날로그) -222 W / mK
알루미늄 5052 (아날로그 AMg2.5) -138 W / mK
알루미늄 6061 (AD33과 유사) -167 W / mK
오늘날 열 및 전기 절연 재료의 여러 대형 제조업체는 금속 기판이있는 인쇄 회로 기판 제조를위한 기본 재료를 생산합니다.
Bergquist (United States)
Laird (Thermagon) (United States)
The materials provided with different characteristics can meet the most demanding tastes of electronic device developers and technicians, and are expected to directly obtain economic benefits in the production stage and subsequent operations of products. These materials themselves meet the requirements of commercial and military standards and can be used in almost any field: from household appliances to military equipment.
For example, a widely used (due to the high price/mass ratio in the production of LED clusters) thermal conductive polymer material based on aluminum and ceramic-T111 (Toke) has the following characteristics:
-1.5mm 유전체 두께 -100μm
동박의 두께는 35 마이크론입니다.
유전체 열 저항 -0.7 ° C / W
알루미늄 기판의 열전도율 (5052-Analog AMg2. 5) -138 W / mK
항복 전압 -3 KV
유리 전이 온도 (Tg) -130
부피 저항 -108MΩ × cm
표면 저항 -106MΩ
최대 작동 전압 (CTI) -600V
에칭, 보호 마스크 적용, 보호 금속 코팅 (HASL) 적용, 마킹 등과 같이 금속 기판으로 인쇄 회로 기판을 제조하는 대부분의 프로세스는 FR-4의 기존 회로 기판을 제조하는 프로세스와 유사합니다. 가공 및 윤곽.
Printed circuit board S is not limited to the use of high-power LEDs on metal substrates, and can also be used in any product, where heat is important and size. The use of such boards greatly simplifies the design of radio electronics, especially at high power, because heat dissipation is no longer strictly dependent on the relative position of the components and the surrounding free space board: heat is dissipated through the substrate. No additional radiators are needed-radiators, tires, etc. As a result, the degree of integration of components on the electronic board increases, and its size decreases.
Printed circuit board S has many advantages compared to traditional boards with metal alkali and E:
열을 발산하기 위해 다른 라디에이터와 특수 열 페이스트를 사용할 필요가 없습니다.
강제 공기 냉각 팬의 필요성을 줄이거 나 제거합니다.
제품의 기계적 강성을 높입니다.
높은 작동 온도에서 고전류 및 고전압에서 작동하는 고전력 장비 구성 요소의 통합을 증가시킵니다.
모든 구성 요소의 열 응력을 줄여 구성 요소의 수명과 제품 내구성을 늘립니다.
이러한 플레이트의 냉각 성능은 열 제거를 쉽게 구성 할 수있게하여 제품 비용에 유익한 영향을줍니다.
회로 기판의 모든 구성으로 인해 장비 공간을 크게 절약 할 수 있습니다.
이 보드는 전자기 호환성과 차폐 성능이 뛰어납니다.
이러한 보드를 사용하면 장비의 신뢰성 (평균 고장 시간)이 향상 될 수 있습니다.
단일 인쇄 회로 기판에 결합 할 수있는 가능성에는 다중 LED, 표준 자동 납땜 기술을 사용하여 장착 된 구성 요소 및 낮은 열이 포함됩니다. 이러한 모든 조합을 통해 소형 고성능 광원을 만들 수 있습니다.
The use of cost-effective lighting systems is one of the most important areas for introducing energy-saving technologies in industry and public utilities. Today, among the lighting energy-saving technologies, the most advanced is the creation of powerful semiconductor LEDs and lighting systems based on them. According to experts, as semiconductors replace electronic lamps in their time, the introduction of new LED lighting technology will gradually almost completely replace traditional luminaires around the world. It seems that the waiting time is not long.