Zoom lens design is complicated. The application of rapid and disciplined procedures in nested iterative loops, with the designer interactively included is the best chance we have to be creative in this situation. This feature of the design process gives us the opportunity to use small computers. The complete zoom lens design procedure is presented from this standpoint with details of many important procedures.

Aspherical projection lens for large screen television has been designed with a peW idea. The designing process based on this idea is analysed. :L INTRODUCTIONAccording to the recent innovation in plastic molding technology for aspherical lenses, an unique lens system, actively using aspherical lenses has been apPariflg.A typical and successful example is the projection lens for a large screen television, which is expected to become the main stream for the coming HDTV era in the near future, because of its compactness, light weight, and proper luminance level.The design of such lens system is quite exhosting work because the limit of aberration correcting ability of aspherical lenses is inestimable and the shape of a designed aspherical lens are not always suitable for molding in consideration with the precision and the productivity.We have been strugling to find an efficient and explicit way in the aspherical optical design for projection lens. The results we have got so far are described here.

According to the recent innovation in plastic molding technology for aspherical lenses, an unique lens system, mostly constructed by aspherical lenses has been appearing. A typical and successful example of such lens system is the projection lens for a large screen television, which is expected to become the main stream for the coming HDTV era in the near future, because of its compactness, light weight, and proper luminance level. We have been trying to find an explicit way in the aspherical optical design for this projection lens.