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22 PCB007 MAGAZINE I OCTOBER 2022 SpeedLight 2D system. It features a twin stage, allowing imaging of the first panel while a sec- ond panel is being registered. e imager con- sists of 288 laser diode beams that are modu- lated by nine polygon mirror modules. Limata GmbH, the German supplier of laser direct imaging systems used in small lot PCB production and photochemical machining, has developed its established UV-P model into the advanced UV-R Series. It can make use of the latest UV diode lasers with multiple wave- lengths and a long operating life. Both models are equipped with one to eight laser heads. Res- olution down to 25-micron lines and spaces is being achieved. A pre-registration module can address up to 64 registration targets to achieve near perfect registration. Solder mask can be imaged using up to three wavelengths for max- imum intensity, to accommodate less sensitive photoresists. A robotic load and unload station can be added for enhanced throughput and optimal interface with other processing equip- ment. Canadian supplier Aiscent Technology has done R&D in digital imaging for more than 15 years. Its system uses DMDR-based photoli- thography and a proprietary high-power laser. Double-sided models currently offered are suitable for production of PCBs, high-resolu- tion photomasks, digital screen imaging, and other customized industrial use. Schmoll Maschinen, the well-known sup- plier of mechanical and laser drilling machines, offers a digital direct imaging (DDI) system ideal for prototyping inner layer, outer layer, and solder mask images. It is based on semi- conductor laser diodes and large (wide) optics. e imager is equipped with two to eight diode lasers. Schmoll also offers micromirror digi- tal imaging (MDI) systems. e unique "light engine" head is mounted to a granite platform providing a precision positioning system. is new technology transfers UV light images to the circuit board substrate utilizing over 2 mil- lion high-resolution micromirror chips. ese systems are available as a single-table unit, a tandem table unit, or the XXL model that can handle a maximum single panel size of 1371 x 914 mm. e units use high-power LEDs and DMDR with multiple wavelengths from 365 to 405 nm. e Swiss company First EIE SA supplies photoplotters, inkjet printers, and direct imag- ers suitable for quick-turn, small lot size shops. Its direct imager is named EDI500. e light source technology is based on TI's DMDR devices with advanced UV lens and very high- pressure mercury arc lamps. Panel registra- tion is done with a building CCD camera or by manual pin registration. Maximum panel size is 620 x 690 mm, but the newer EDI700 can handle an even larger panel size. Visitech is a Norwegian company that sup- plies optical modules (optical subsystems) for direct imagers. e Luxbeam Rapid System (LRS) is based on TI's DLPR (micromirrors) and multiwavelength LED light sources, emit- ting in the range of 350 to 440 nm. Five mod- ules are available with different resolution capabilities: LLS2500 (2.5-micron t/s); LLS04 (4-micron t/s); and LLS06 (6-micron t/s) with two more up to 30-micron t/s. Optical multi- plexing allows the units to achieve their very fine resolution. Front to Back Registration It is desirable to achieve good front-to-back registration. ere are several ways to achieve this, some without the need to drill target holes on the panel before exposure ("hole-less regis- tration"). Figure 3 shows four methods utiliz- A pre-registration module can address up to 64 registration targets to achieve near perfect registration.