Abstract: In the assembly of a device package, an optoelectronic device, such as a light emitting diode (LED) or a photodiode, mounted on a header is aligned with a lens, such as a spherical lens, mounted in a housing by making a light beam from a microscope incident on the lens so that light reflected from the lens creates a symmetrical reference image. Light emitted by the device (LED) or reflected from the device (photodiode) forms an object image of the active area of the device. The two images are detected by a camera and are compared (real-image observation by an operator or electronic image comparison by a computer). The device on an x-y table is moved until the object image is centered with respect to the reference image. Then the position of the device within the package is fixed by epoxying, or otherwise securing, the header to the housing.