Larger LED boards may be prone to bending or warping. During component assembly, the LED circuit board passes though the convection reflow oven. This process allows solder paste to reflow, permanently attaching all optoelectronic components. However, the heat in this extreme environment can also cause the entire printed circuit board to warp to some extent. In other cases, long narrow circuit boards may be prone to natural bending during normal use in the field. In either case, it is important that these stresses do not result in damage to surface mount LED lights. This is why LED light and component orientation can play a critical role in many custom LED lighting design.
The PC board serves as the primary structure to physically connect and sustain each individual SMT LED light as well as other required electronic components. Custom LED circuit boards permit flexibility for strategic light emitting diode placement while guaranteeing a permanent physical bond. This is critical in many applications demanding precise LED light placement to ensure favorable optical results, such as with many LED tail lights. Traditional LEDs contain two wire leads that pass through small holes in the PC board. Manual LED soldering is an option; however, a wave-soldering machine is more suitable for high volume manufacturing. Modern LEDs are typically surface mount technology, referred to as SMT. SMT components physically bond to surface pads on the top or bottom circuit layer, so no holes are required through the circuit board.
Every LED as well as all other electronic components shares at least one electrical connection with another LED or component. A network of flattened copper conductors commonly referred to as traces, provides these simple LED circuit nets necessary for current flow between corresponding components. Trace length, width, and thickness directly affect the amount of total current that can safely pass though the trace. High-density layouts may contain too many traces to physically fit onto the top and bottom circuit layers. Multi-layer PC boards offer inner layers providing room additional traces. Incorporating interior circuit layers does not necessary increase the overall PC board thickness.
The most commonly overlooked function of the LED circuit board is the thermal function. Electrical current produces heat to some extent, whether it is passing through an LED or copper conductor. It is extremely important to manage this heat, taking into account that LED efficiency is lost as temperatures increase. Modern surface mount LEDs feature a specialized slug integrated into the LED casing. This slug performs the critical task of conducting heat produced by the interior die away from the LED. Traces and solid copper areas on the PC board can absorb and dissipate the thermal energy transferred from this slug. However, if printed circuit board design is not carefully considered, the thermal energy may have no place to dissipate. As a result, luminous output degrades and efficiency is lost. The LED may even suffer from irreversible damage to the internal die. Modern LED boards now contain a metal core to aid in heat disipation. The LED metal core PCB provides a much lower thermal resistance from the LED junction to ambient air within the surrounding environment.
Subsequent to completion of the circuit board layout, our engineering staff will produce a series of specialized files commonly referred to as Gerber files. The Gerber files are machine-readable files generated from a human readable version, referred to as design files. The Gerber files are required for the printed circuit board fabrication process. The files contain information such as trace, hole, and milling data. Lunar Accents Design maintains a client Gerber file archive for individual projects. However, we do furnish Gerber files to the client by special request, at no additional cost. All Gerber files must correspond with a project name and revision. Our standard revision code follows an alphabetical format starting form A. The Gerber Scientific Instruments Company originally conceived the Gerber file. Several common Gerber file extensions include .GBR, .GBX, .TOP, and .BOT. For additional information on Gerber files, please contact a member of our engineer team.
Lunar Accents Design Corporation also offers custom design services for customers who require circuit boards for a specialized LED lighting solution. If your lighting solution requires a custom fabricated printed circuit board, we offer a full range of LED PCBs containing various substrates and finishes. A standard FR4 circuit board is suitable for most traditional surface mount and through-hole LED applications. Optional finishes include standard tin/lead, lead-free, gold, copper, and silver. Circuit board thicknesses are available ranging from 0.020" to 0.125". Solder masking is also available in a variety of colors including green, white, black, red orange, blue, and yellow. Most high power LED applications require a specialized circuit board designed to dissipate large amounts of heat. Aluminum and steel substrate circuit boards contain a much lower thermal resistance when compared to traditional thermal via, FR4 configurations. Maintaining minimal thermal resistance is critical for many high power LED lighting applications. Lunar Accents Design recommends an LED metal core PCB for most "illumination" LED projects, which rely on the light source to illuminate a room or other specified area. Surprisingly, aluminum and steel substrate products are comparable in cost to standard FR4 materials. Our highly experienced engineering team specializes in custom circuit board layouts, thermal management, as well as LED circuit design including LED metal core pcbs. Please refer to our assembly page for details regarding component assembly.
Lunar Accents Design Corporation stocks a variety of circuit boards designed specifically for LED lighting applications. Before investing in a custom designed board, we recommend evaluating one of our stock LED circuit boards. Incorporating one of our stock LED boards into a custom lighting application can save valuable time as well as potentially expensive engineering fees. Many of our stock LED circuit boards are capable of being custom tailored to meet a wide range of custom lighting applications. We offer bare boards as well as fully populated or partially populated LED boards. Some clients prefer pre-populated surface mount components, and perform through-hole assembly in-house. This service is beneficial for customers who offer customized LED products, where each product contains several common surface mount components. Our standard, stock LED board accepts up to seventy-two 5mm or 3mm LEDs. The circuit board measures 21.6 inches long by 0.5 inch wide. The circuit architecture is ideal for RGB color mixing applications. Our current design revision is divisible into twelve increments each measuring 1.8 inches in length. For additional details on this PCB, refer to sample LED products located in the upper right corner of our webpage. We also stock a similar surface mount version capable of accepting 36 surface mount LEDs. The surface mount circuit board is suitable for LED taillight applications. Both boards contain pads to accept 1206 surface mount resistors, which are convenient for applications utilizing resistors to limit LED drive currents.