|Budget Amount *help
¥3,000,000 (Direct Cost : ¥3,000,000)
Fiscal Year 1999 : ¥3,000,000 (Direct Cost : ¥3,000,000)
Each elements such as laser source, polygon mirror, fθ lens, jitter measuring device were manufactured in order to measure the jitter. It can be used as a dry process setter after assembling these elements. First, stress analysis on the polygon mirror was carried out by FEM.Since the polygon mirror rotated at high speed, we examined how the centrifugal force distorted the shape of mirror surface. Material and shape for the shrink fitter were designed. Using each produced element, the dry process setter was constructed. Afterwards, the jitter was measured for an operation check. The consideration based on the geometry was carried out in order to clarify the effect of the mirror surface on the jitter, and the theoretical formula to calculate the jitter, as mirror surface deviated from the ideal plane, was completed. Next, the shape of each mirror surface of polygon mirror having the 6 planes was measured by laser interferometer. Measured mirror surface was approximated by the seventh or
eighth polynomial. By differentiating the approximation at the optional place, it is possible to obtain the gradient of the mirror surface at the optional place, and it is possible that the jitter is theoretically obtained. Using the test equipment, the jitter of polygon mirror of which the mirror surface shape had already been measured was measured. The measured value of the jitter was in good agreement with the theoretical value.
The shape of mirror surface was measured in the stationary state. The shape of the mirror surface will be distorted from the stationary state, since centrifugal force was acted on the rotational mirror. Then, the jitter analysis was carried out again, after the calculated shape change of mirror surface on the consideration of centrifugal force was added. As the result, the calculated value approached more experimental value. By the research done this time, the jitter of the rotational polygon mirror could be obtained by measuring shape mirror surface shape in the stationary state. Less