1. There have been many methods to fabricate microlens arrays, such as, the ion-exchanging, molding. plasma CVD, interfacial-gel copolymerising, photolytic, and monolithic techniques. Among them, the ion- exchange process has achieved the better improvements and results in theory and practice. The authors obtained analytic solutions of the diffusion equations for window and disc mask processes in fabricating ion-exchanged planar microlens array, derived the optimum index distribution for disc-mask microlens (DM lens), gave the image matrix of microlens, fabricated the divergent disc- mask planar microlens array and show the parameters and the picture taken with the array.