PerkinElmer Inc. of Wellesley, Mass., has purchased Elcos AG of Pfaffenhofen, Germany, for $15 million in cash and the potential for earn-out payments based on the performance of the business. Elcos supplies custom LEDs for biomedical and industrial applications, including blood glucose monitoring and pulse oximetry. The company's technology, customer and application bases combined with PerkinElmer's global sales, application and support organization are expected to result in expanded technological offerings.