1. Field of the Invention
The present invention relates to a light adjusting apparatus that adjusts light by inserting/removing a light adjusting section into/from an optical path.
2. Description of the Related Art
Image pickup devices having an image pickup function are widely used in various fields, and among those fields, there is a field of small image pickup devices having a relatively small shape. Examples of such small image pickup devices include electronic endoscopes including a micro-video scope, optical microscopes provided with an image pickup function and portable devices provided with an image pickup function.
Since downsizing is given priority in conventional small image pickup devices, a fixed focus lens, a fixed opening diaphragm, a fixed characteristic filter and the like are adopted as optical elements such as a lens, a diaphragm or an optical filter.
In contrast, high image quality is required also for such small image pickup devices in recent years, and there is a growing demand for adopting a focus lens, a variable diaphragm, and a variable characteristic filter as the aforementioned optical elements of light adjusting apparatuses, that is, functioning as a light adjusting apparatus that adjusts light.
Thus, many techniques are proposed which seek to downsize light adjusting apparatuses so as to be applicable to small image pickup devices.
As an example, Japanese Patent Application Laid-Open Publication No. 9-22042 describes an electromagnetic drive apparatus disposed around a taking lens which is provided with a yoke, a coil and a permanent magnet opposed to the yoke, the electromagnetic drive apparatus being configured to generate a magnetic force in the yoke by energizing the coil to cause the permanent magnet to rotate. By attaching, for example, a shutter blade rotatably and integrally to the permanent magnet as a light adjusting section, it is possible to switch between a state in which the shutter blade is positioned on an optical path and a state in which the shutter blade is retracted from the optical path.