Light-weight objective lens for DVD pickup

The size and weight of the pickup head will influence the form factor and the bandwidth of DVD. A MEMS-type DVD pickup was proposed, in which the objective lens will be manipulated with a micro actuator for focusing. A high order diffractive objective lens has been designed specially for meeting the request on reduced weight by optimizing the surface relief profile of each zone one by one. The simulation by ray tracing tool shows a well corrected geometrical aberration and a near diffraction limit focal spot. The lens is expected to be produced with gray scale mask photolithography, and the weight will have only one third of that of its refractive counterpart.