Conventionally it has been problematic when dust or the like exists in the neighborhood of the focal plane of a photograph lens of a digital single reflex camera with interchangeable lenses, because the solid-state image capturing device captures the shadow of the dust. It is believed that such dust comes into the lens from outside at the time of lens exchange, or is caused by microscopic abrasion powder of a resin or the like serving as a structural member of the camera, which is generated along with an operation of a shutter or mirror inside the camera. If the dust generated by such causes gets in between a protection cover glass of the solid-state image capturing device and an optical filter, such as an infrared-ray filter or an optical low-pass filter (hereinafter referred to as an LPF) arranged on the entire surface of the cover glass, the camera must be taken apart to remove the dust. For this reason, it is extremely effective to have a sealing structure to prevent dust from getting in between the cover glass and the optical filter of the solid-state image capturing device.
However, in a case where dust is attached to the surface of the optical filter that is opposite to the solid-state-image-capturing-device facing side, if the dust is in the neighborhood of the focal plane, a problem still remains in that the shadow of the dust is captured by the solid-state image capturing device.
To solve the above problem, there is a technique for cleaning the cover glass surface of the solid-state image capturing device with a wiper (e.g., refer to Japanese Patent Application Laid-Open (KOKAI) No. 2003-005254 (page 8, FIGS. 1 and 9)).
According to the camera structure described in KOKAI No. 2003-005254, it is possible to remove dust attached to the cover glass surface of the solid-state image capturing device or the outermost surface of a dust control structure without removing the lens or taking the camera apart.
However, because the cover glass surface of the solid-state image capturing device or the outermost surface of the dust control structure is rubbed by the wiper, in a case of hard dust such as metal powder, there is a risk of scratching the cover glass surface of the solid-state image capturing device or the outermost surface of the dust control structure. Furthermore, because the dust removed by the wiper floats in the camera, it is problematic that the dust that has once been removed is attached again to the cover glass surface of the solid-state image capturing device or the outermost surface of the dust control structure.
Besides the above, there is a structure that prevents dust attachment to the surface of an image capturing device by utilizing cleaning film inserted between a focal plane shutter and the image capturing device (e.g., Japanese Patent Application Laid-Open (KOKAI) No. 2002-271662 (page 7, FIG. 7)). More specifically, when dust is attached to the cleaning film, the portion of film is taken up to remove the dust attached to the surface. Accordingly, it is possible to remove dust without scratching the image capturing device surface.
However, since this structure requires space for loading and taking up the cleaning film, and also requires an exchange of the cleaning film at appropriate timing, it causes problems of an enlarged size of the camera and a complicated operation.
USPTO Backgrounds
USPTO Backgrounds