Abstract: It is included an internal gear (2), an external gear (3) having flexibility, and a wave generator (4) that forms a meshing part (P) with the internal gear (2) in the external gear (3) and moves the meshing part (P) in a circumferential direction of the internal gear (2). The wave generator (4) is configured such that the meshing part (P) is formed at three or more positions in a circumferential direction of the external gear (3). A value (DpF/ZF) obtained by dividing a working pitch diameter DpF of the external gear (3) by the number of teeth ZF is greater than a value (DpR/ZR) obtained by dividing a working pitch diameter DpR of the internal gear (2) by the number of teeth ZR.

Abstract: It is included an internal gear (2), an external gear (3) having flexibility, and a wave generator (4) that forms a meshing part (P) with the internal gear (2) in the external gear (3) and moves the meshing part (P) in a circumferential direction of the internal gear (2). The wave generator (4) is configured such that the meshing part (P) is formed at three or more positions in a circumferential direction of the external gear (3). A value (DpF/ZF) obtained by dividing a working pitch diameter DpF of the external gear (3) by the number of teeth ZF is greater than a value (DpR/ZR) obtained by dividing a working pitch diameter DpR of the internal gear (2) by the number of teeth ZR.

Abstract: A method of and apparatus for efficiently correcting an aberration of an optical system used to record a hologram at the stage of reconstructing an image of the hologram. At the stage of reconstructing an image of a hologram (3), which contains the record of interference fringes formed by a reference plane wave and an object wave modulated by a sample, by applying a plane wave for reconstruction to the hologram (3) from a laser (1), an aberration of an optical system used to record the hologram (3) is canceled by the phase distribution on a liquid crystal panel (6) having a spatial phase modulation function, which is disposed on the Fourier transform plane, thereby correcting the aberration. The phase distribution on the liquid crystal panel (6) can be changed flexibly by a computer (9) in accordance with the aberration coefficients or degree of defocusing of the recording optical system.