Development of a PCB printer using an ultraviolet laser diode

Abstract

When electrical engineers are conducting research and development, they often require preliminary testing of their new circuit design. This requires a small production of printed circuit boards (PCBs) to be produced. This could lead to outsourcing to a board house, which adds time and cost to the project. Our goal is to develop a low-cost PCB printer, using an ultraviolet laser, in order to reduce turn-around time and to be cost effective. This project would serve valuable to all electrical engineers, whether it be a student, hobbyist, or full-time employee. Pre-sensitized copper clad boards have been around for several years. Traditionally, the desired circuit design is printed onto a transparency film which is then placed on top of the pre-sensitized board. Then, the board is exposed to a uniform ultraviolet fluorescent light for several minutes. The board then proceeds through the rest of the steps in the fabrication process (developer solution, etchant solution, cleaning, masking, etc.) However, the rise of consumer products such as Blu-Ray players and select home theater projectors has significantly reduced the cost of near-ultraviolet laser diodes in the 400-450nm range. These new diodes have the capability of replacing the ultraviolet lamp typically used in this process. By combining this focused beam of light with some precision mirrors (laser galvanometers) and basic circuits, we propose to “print” the circuit design directly onto the pre-sensitized board. This means no transparency film will be needed, which results in reduced time, cost and materials. By utilizing a new source of ultraviolet light (laser diodes vs. lamps), this project plans to revolutionize the way small scale PCB production takes place. The convenience of having a portable desktop PCB printer can serve useful to every electrical engineer. Without the hassle of transparency film and high-power UV lamps, this project plans to reduce time, waste materials, and power consumption for small scale PCB production.