US Patent 7324717 Photonic device with integrated hybrid microlens array

A microlens structure is mounted directly onto the upper surface of a packaged VCSEL device and positioned to locate microlenses directly over corresponding VCSEL elements. The microlens structure includes a block-like pedestal having a lower surface that faces the upper surface of the VSCEL device. The microlenses are formed in a central region of the lower surface, and several legs (stand-offs) extend from peripheral edges of the lower surface. During assembly, the VCSEL device is positioned under the microlens structure such that each microlens is aligned over its corresponding VCSEL element, and then raised until the legs contact the upper surface of the VCSEL device. The legs serve to self-align the microlenses to the VCSEL device, and are sized to maintain an optimal distance between the microlenses and the VCSEL elements. The pedestal is attached to a carrier plate that is secured to an IC package housing the VCSEL device.