To officially launch its i-series of high-efficiency, environmentally friendly automobiles at the Frankfurt International Motor Show IAA, BMW used the services of Lobo (Aalen, Germany), a laser light-show company, to create effects that included a “birthing tunnel” of blue laser light. In keeping with the “green” theme of the launch, Lobo used energy-efficient optically pumped semiconductor laser (OPSL) technology in the show. A pre-launch for press and industry insiders was held two months before show opening. The launch was conceived by the BlueScope agency (Berlin) and managed by Rockservice (Salzgitter, Germany). The overarching concept was to unveil each of the cars through a birthing tunnel formed of light. The pre-launch presentation included other effects also, such as moving laser patterns and sheets of light that hid all areas of BMW’s large exhibition area that were not intended for the public viewing at that time. The lasers were also used to create a roof of light over the entire BMW exhibition, covering all of Hall 11.0 at the Exhibition Center in Frankfurt.
The laser birthing canal and other effects were created using nine of Lobo’s Sparks laser light engines, based on OPSL laser heads made by Coherent (Santa Clara, CA), resulting in a total output power of more than 150 W. “In addition to fulfilling the creative concept created by Bluescope, this unique laser display had to fulfill three other important prerequisites,” says Alex Hennig, Lobo’s creative director. “We had to exactly match BMW’s corporate blue color, we had to do this with a small carbon footprint congruent with the whole concept of these i-series cars, and we had to provide a visually bright yet eye-safe display.”
Two blue wavelengths for precise color control
Exactly matching BMW’s corporate blue was a particularly interesting challenge, says Hennig. “Color is actually a human perception and one that varies depending on the location, background lighting, and other factors,” he notes. “So we had to be able to tweak this on site to match the way other blue light components of the BMW display appeared in the actual show setting.” To do this, Hennig used modified RGB Sparks engines that incorporated two blue lasers, rather than a single laser. These were Coherent Taipan lasers emitting at 460 and 488 nm. This enabled more complete and subtle control over the final blue output than would be possible just using a standard red-green-blue setup.
The lasers’ small carbon footprint results from their diode-pumped solid-state nature; in addition, there is no internal requirement for tightly matching the diode output wavelength used to pump the OPSL’s semiconductor gain chip, thus eliminating the power required to closely control the diode operating temperature.
Sparks laser projectors also deliver the industry’s brightest laser effects for a given power level for two reasons. First, OPSL heads already deliver superior beam quality, enabling low divergence projection of beams and images. The Sparks laser projectors use Lobo’s post-collimated scanning (PCS) system, which lowers beam divergence by a factor of three, according to Lobo. This helped to enable a bright display having the minimum possible carbon footprint for its size.
John Wallace | Senior Technical Editor (1998-2022)
John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.