background FPC, flexible circuit board. The number of circuits of an FPC can exceed 100, but only occupy a thickness of 0.2mm. Although more expensive than cables, it is widely used in compact smart hardware. Especially mobile phones, smart watches and other scenes. Today's focus is on soldering FPC gold finger design techniques. The quality of hardware products is good or bad, and design accounts for more than half! The benefits of welding FPC FPC welding can save two board-to-board connectors, or save one Zif plug connector, saving the cost of 1-2 dollars. Therefore, in many low-end products, the use of welded FPC. (Manual welding, faster than machine placement.) Welding FPCs, if designed well, save money over connectors and are stronger than connectors: Welding is definitely more solid than buckles. The disadvantage is that the welding area is larger than the connector, and maintenance is more complicated. Double-sided gold finger + tin hole Although the gold finger corresponds to only one layer of the pad, the FPC's gold finger can't do only one layer. FPC is a non-metallic substrate and heat transfer is slow. If there is only one layer of gold finger, the heat transfer of the soldering iron during manual soldering will not pass and it will be difficult to solder. In the same way, tin holes are punched in the pads for the purpose of heat transfer and allow molten solder to flow between the upper and lower layers. This is the two sides of the same welded FPC Double-sided wiring + extra vias Early engineers only made double-sided pads. However, FPC circuit breakers often occur during product production. Later, it was found that the quality of the FPC manufacturers cannot be blamed. Instead, they are too stressful and easy to break. They must be improved through design methods. Finally, we invented the "double-sided routing + additional vias" approach, and ultimately solved this problem. No matter how you fold, FPC will not be bad. The reason for the damage: The FPC can be bent and is based on the fact that the copper foil is stretched as a whole. After welding by FPC, the welding surface cannot be stretched. Once pulled up, the stress point is concentrated on the edge of the welding surface and the edge will be broken. After the double-sided wiring was changed, the problem of bottom cracking was not solved. However, because there were two layers of wiring, one layer and one broken layer would not cause a signal break. In the near-infrared, the wide spectrum of the infrared spectrum, the total reflection mirror is coated with a high reflectivity gold film. Gold Mirror,Gold Reflector,Protected Gold Reflector,Protected Gold Mirror Bohr Optics Co.,Ltd , https://www.bohr-optics.com
In order to enhance the adhesion of the gold film, a very thin chromium base film is plated.
The gold film of the silicon substrate has strong adhesion, high thermal conductivity (the thermal conductivity is about 111 times that of glass), and the heat resistance is much better than that of the glass substrate.
Because it is a metal film, the reflectance or reflectance wavelength characteristics will not change greatly with the incident angle.
·The gold film has a high reflectivity in the infrared spectrum. The light that is not reflected is completely absorbed by the film and will not pass through.