Patent ID: 7099076
Filing Date: 2006-08-29
Classification: G02B

Abstract:
1. Binoculars which include a pair of observation optical systems each having an objective optical system, an erecting optical system and an eyepiece optical system, the binoculars comprising: a focusing mechanism that is used to move a part of observation optical systems for focusing; a convergence value compensating mechanism that compensates for a convergence value by displacing displaceable optical elements which are at least parts of the objective optical systems, respectively, in association with actuation of the focusing mechanism; and a light shielding mechanism configured to shield light for preventing light from entering through a clearance caused in accordance with displacement of the displaceable optical elements by actuation of the convergence value compensating mechanism; wherein the focusing mechanism is configured to carry out focusing by moving the pair of displaceable optical elements, wherein the binoculars further includes: a pair of guide shafts corresponding to the pair of displaceable optical elements, the pair of guide shafts being arranged in parallel with the corresponding displaceable optical elements, the pair of guide shafts guiding the corresponding displaceable optical elements when moved by actuation of the focusing mechanism, the pair of guide shafts serving as turning centers of the corresponding displaceable optical elements, respectively; a pair of engaging portions formed on a pair of frames that hold the pair of displaceable optical elements, respectively; and a pair of guide rails provided with respect to the pair of displaceable optical elements, respectively, the pair of engaging portions being slidably engaged with the pair of guide rails, respectively, the pair of guide rails having inclined portions that incline with respect to the optical axes of the pair of displaceable optical elements at least parts thereof, respectively, wherein, when the pair of displaceable optical elements are moved for focusing with the pair of engaging portions being engaged with the inclined portions of the pair of guide rails, respectively, the pair of displaceable optical elements turn about the pair of guide shafts, respectively, and a distance between the optical axes of the pair of displaceable optical elements changing as the pair of displaceable optical elements turn, whereby the convergence value is compensated; further comprising a main body that accommodates the displaceable optical elements, wherein the light shielding mechanism includes light shielding members, which are respectively displaced along with the displaceable optical elements, for preventing light from entering through the clearance produced outside each of the displaceable optical elements, when facing in a direction parallel to an optical axis direction of the displaceable optical elements, in a state in which the distance between the optical axes of the displaceable optical elements is comparatively small, and wherein each of the light shielding members includes an arc shape portion, whose outer circumferential shape has a form of an arc centering around the corresponding guide axis, in the vicinity of the farthest position from the corresponding guide axis, and the arc shape portion is brought into contact with or is in proximity to an inner wall of the main body.