The light source is a tiny LED. Only a reflector turns this point of light into a purposefully targeted light field. To give the light its precise direction, many calculations, measurements and prototype experiments are required. It takes many months for a new “light design” to enter mass production.
At the end of assembly all functions of every headlight or rear light are tested. It is not enough for the product to simply shine, we check light output, light field, light/dark boundary and much more. This, supported by measuring devises, is done manually by Busch + Müller employees.