Patent ID: 8025449
Filing Date: 2011-09-27
Classification: G03B

Abstract:
1. An image pickup apparatus comprising: a shutter device; an image pickup element adapted to sequentially acquire time-series images regarding object images passing through an exposure opening of the shutter device; and control means for controlling operation of the shutter device and operation of the image pickup element; wherein the shutter device includes a rear curtain traveling from an exposure start position to an exposure end position and then covering the opening, a rear curtain drive member allowing the rear curtain to travel from the exposure start position to the exposure end position, biasing force application means for applying a biasing force to the rear curtain drive member, the biasing force being adapted to shift the rear curtain in a direction from the exposure start position toward the exposure end position, holding means for holding the rear curtain drive member against the biasing force through an attractive force based on an magnetic force of a permanent magnet, and holding-releasing means for releasing the holding of the rear curtain drive member by allowing energization of an electromagnet to generate a magnetic flux having a direction of cancelling a magnetic flux of the permanent magnet to reduce the attractive force, the control means allows the image pickup element to acquire the time-series images regarding the object image passing through the opening, in a state where the rear curtain drive member is held at a given position by being attracted by the holding means through the attractive force based on the magnetic force of the permanent magnet and the rear curtain is maintained at the exposure start position, and the control means allows the energization of the electromagnet to start at given timing after issuance of a shooting instruction regarding an actual shooting image to release the holding of the rear curtain drive member and allows the rear curtain through the biasing force to travel from the exposure start position to the exposure end position, wherein the shutter device further includes a charge member adapted to increase the biasing force by shifting the rear curtain drive member to the given position, an attracting surface of the holding means is disposed at a position opposed to a to-be-attracted member of the rear curtain drive member when the rear curtain drive member is at the given position, and the charge member shifts the rear curtain drive member to the given position to allow the to-be-attracted member to be attracted to the attractive surface through the magnetic force of the permanent magnet, thereby holding the rear curtain drive member at the given position through the magnetic force of the permanent magnet.