Cylindrical plastic lens array fabricated by a micro intrusion process

A cylindrical plastic lens array fabricated by a newly developed micro intrusion process is demonstrated and characterized. A 500 /spl mu/m thick PC (polycarbonate) film is used as the raw material and hot embossed with nickel mold inserts that are made by a single-layer LIGA process. High-aspect-ratio circular holes of 80 /spl mu/m in diameter and 200 /spl mu/m in depth are designed to form the plastic cylindrical lens. The plastic material is intruded into the circular holes and stopped at desired distance by adjusting the embossing load, temperature and time. The optical properties of these microlenses have been characterized by measuring their focal lengths. The average radius of curvature is 56.1 /spl mu/m with a standard deviation of 0.46 /spl mu/m and the average height is 190.6 /spl mu/m with a standard deviation of 4.9 /spl mu/m. The focusing capability of the lens is demonstrated by comparing the image of laser light with and without using the lens. When the projection screen is placed 200 /spl mu/m away from the lens, the FWHM for the lens is 110 /spl mu/m while the FWHM of the optical fiber is 300 /spl mu/m.