Design and analysis of gratings and diffractive optical elements for displays

Recent progress in the fabrication technology of micro surface relief structures realizes diffractive optical elements (DOEs) for various applications. Intensive researches on useful surface relief structures have been continued for many years. In this paper, our studies on the analysis and design of surface relief structures, especially for applications in displays, are introduced. In the first place, a binary surface relief structure on a subwavelength scale for general beam shaping is proposed and the optical characteristics of that are investigated by use of the rigorous electromagnetic analysis. The proposed structure enables both phase and amplitude distributions of the incident optical field to be modulated continuously. Next, the concepts and the design of boundary-modulated DOEs are introduced. It is noticed that the aperture shape of DOEs can be modified optimally to make more delicate diffraction images. What both researches have in common is to extend the degree of freedom in optimal design. Finally, as a component of the backlight system of LCD panel, the radiometric characteristics of a pyramidal prism sheet that is a kind of thick surface relief structure is discussed with computer simulation.