Abstract: A metal photoetching product comprising at least one large cavity of minor axis W1S, major axis W1L and depth D1 in a surface of the product, wherein one or more cavities are included inside at least one of the at least one large cavity, and a smallest hole among the cavities has minor axis of W2S, major axis W2L, and depth D2; and the product satisfies the following dimensions, D1+D2=plate thickness D, 0.02 mm?D?2 mm, 0.4×D<W1S<D, and 0.2×D<W2S<0.8×D.

Abstract: A motor driving device generates a first PWM control signal for PWM driving each phase (1u, 1v, 1w) of stator windings of a motor (1) and a second PWM control signal for synchronously rectifying the phases (1u, 1v, 1w) on the basis of a current command signal indicating the level of a current to be supplied to the motor (1) and a phase current signal indicating the level of a current actually supplied to the motor (1) and drives the motor (1) according to the first and second PWM control signals. The motor driving device includes a synchronous rectification control switching section (21) for controlling the presence or absence of a mask for the second PWM control signal according to a provided control switching signal.

Abstract: A metal photoetching product comprising at least one large cavity of minor axis W1S, major axis W1L and depth D1 in a surface of the product, wherein one or more cavities are included inside at least one of the at least one large cavity, and a smallest hole among the cavities has minor axis of W2S, major axis W2L, and depth D2; and the product satisfies the following dimensions, D1+D2=plate thickness D, 0.02 mm?D?2 mm, 0.4×D<W1S<D, and 0.2×D<W2S<0.8×D.

Abstract: In a color cathode-ray tube, only a foreign matter adhering to a shadow mask is removed effectively without thermal deformation of the shadow mask or thermal denaturation of phosphors.An electron beam produced by an electron gun incorporated in a cathode-ray tube itself is scanned or irradiated to all over a shadow mask of the color cathode-ray tube. The radiant state of a fluorescent screen at this stage is checked to detect a foreign matter adhering to the shadow mask. The electron beam is deflected to align with the position at which the foreign matter is detected, and then irradiated to the foreign matter in the form of pulses. Thus, the foreign matter is heated and removed.