Abstract: Manufacturing method for variable shape mirrors suitable for mass production includes steps: for forming first grooves and second grooves along boundaries between areas to be variable shape mirrors on a surface of first wafer to be support substrate and a surface of second wafer to be mirror substrate; for arranging first and second wafer so that support pillars and piezoelectric elements are sandwiched between first and second wafer at areas with surface on which second grooves are formed facing inward for bonding; for dividing second wafer into mirror substrates by flattening process of outer surface of second wafer until at least reaching second groove; for dividing first wafer into the support substrates by breaking first wafer along first grooves; and for forming reflection film on outer surface of each of mirror substrates obtained by the dividing step.

Abstract: Manufacturing method for variable shape mirrors suitable for mass production includes steps: for forming first grooves and second grooves along boundaries between areas to be variable shape mirrors on a surface of first wafer to be support substrate and a surface of second wafer to be mirror substrate; for arranging first and second wafer so that support pillars and piezoelectric elements are sandwiched between first and second wafer at areas with surface on which second grooves are formed facing inward for bonding; for dividing second wafer into mirror substrates by flattening process of outer surface of second wafer until at least reaching second groove; for dividing first wafer into the support substrates by breaking first wafer along first grooves; and for forming reflection film on outer surface of each of mirror substrates obtained by the dividing step.

Abstract: A dynamic pressure bearing device induced a housing having a sleeve and a thrust receiver and a shaft fit into the sleeve. Herringbone-shaped grooves for generating dynamic pressure comprising outer groove segments and inner group segments are disposed to at least one of the inner cylindrical surface of the sleeve and the outer cylindrical surface of the shaft at two axially spaced apart positions. The axial length of the outer groove segment is longer than that of the inner groove segment, and the difference of the axial length for the outer and the inner groove segments is greater in the lower herringbone-shaped grooves than in the upper herringbone-shaped grooves.