Development of a grating interferometer with application to HDD servo-track writing

The development of a grating interferometer with application to the angular measurement of a hard disk drive actuator arm for application to the servo-track writing process is presented. First, the theoretical background related to the linear type grating interferometer is presented, and this theory is extended to the measurement of the angular displacement of a hard disk drive actuator arm using a linear grating. A vector based diffraction technique has also been developed as a tool for visualization and analysis of the grating interferometer design. Finally, experimental setups and results from a prototype grating interferometer design are presented and discussed to demonstrate the feasibility of the grating interferometer measurement system.