Enhancement of depth-of-field in a direct projection-type integral imaging system by a negative lens array

We propose a method for enhancing depth-of-field, in which the spot size on a marginal depth plane is reduced. This method is implemented in a projection-type integral imaging system using a negative lens array without a diffuser. Numerical simulation results show that the spot size is merely 5.7% of that in a conventional system. Thus, the depth-of-field in the proposed system is enhanced by 17.5 times over that in a conventional system. Optical experiments confirm good agreement between the results and numerical predictions.