aluminum substrate and glass fiber board, belong to the carrier of printed circuit board, FR4 uses insulation material. The difference is that aluminum substrate uses conductive aluminum plate, thermal conductivity is much higher than glass fiber board, so it is generally used in power components such as easy to heat occasions, such as LED lighting, switches and power drivers.
There are two kinds of printed circuit boards that use insulating materials. One is the board made of fiber braided fabrIC, also known as epoxy board. The texture of the braided fabric can be clearly seen from the appearance. This kind of plate strength and toughness are relatively good, not easy to crack, but the price is also higher. Today's mobile phones and computers use this circuit board. The other is a board made of insulating paper, commonly known as "paper board". It is brittle but much cheaper, and is often used in cheap appliances.
One is the glass fiber board is the most commonly used medium in the circuit board, such as the commonly used FR4 board, which is based on glass fiber, the copper sheet is attached to form a copper coated plate, after a series of reprocessing to form the printed circuit board. The copper foil of glass fiber board is fixed by binder and glass fiber board, generally resin type. Glass fiber board itself is insulated, and has a certain flame retardant, but its thermal conductivity is relatively poor. In order to solve the problem of thermal conductivity of glass fiber board, some components that have requirements for heat dissipation generally adopt the way of heat conduction through holes, and then heat dissipation through the auxiliary heat sink. But for LED, it can not be heat dissipation through the positive contact with the heat sink. If the heat conduction through holes is used, the effect is far from enough. So LED will generally use aluminum substrate as circuit board material.
printed circuit boards made of insulating materials can be divided into single panel, double panel and Multilayer board. This is mainly because the conductive copper thin printed circuit can not cross, like an overpass, only with multi-layer three-dimensional cross way to meet the needs of the criss-cross. The layers are joined by sunk holes.
Aluminum substrate is a printed circuit board that has been widely used in recent years. At present, it is mainly used for lamp bead cooling in LED lamps. Since aluminum is conductive, there is an insulating film between the conductive copper sheet and the aluminum sheet. This layer of film determines the quality of the aluminum substrate, which must meet the requirements of insulation and bonding firmly, while also having very low thermal resistance. Some high power LED lights short life, and the use of inferior aluminum substrate has a certain relationship.
The structure of aluminum substrate and glass fiber board is basically SIMilar, the difference is that the glass fiber is replaced by aluminum. Because aluminum itself is conductive, if the aluminum is directly covered with copper, it will cause short circuit, so the binder in the aluminum substrate in addition to the binding material, but also as the insulation material between copper and aluminum plate. The thickness of the binder will have a certain impact on the insulation of the plate, too thin insulation is not good, too thick will affect the heat conduction.
Although aluminum is conductive, but between copper foil and aluminum is insulated by resin, so the front of the copper foil is as a conductive line, the back of the aluminum as a thermal conductivity material, it is not communicated with the front of the copper foil. The aluminum is insulated from the copper foil by a resin, but it has a pressure range. In addition to aluminum substrate, there is a higher thermal conductivity of the Copper substrate, this plate is commonly used in power components, its cost is much higher than aluminum substrate.