Radiant energy – Photocells; circuits and apparatus – Photocell controls its own optical systems
Reexamination Certificate
1999-05-26
2001-05-01
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controls its own optical systems
C250S208100, C396S052000
Reexamination Certificate
active
06225613
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical device, which is provided with a tremble preventing apparatus, to correct trembling caused by a hand tremble and so on.
2. Description of the Related Art
Conventionally, an optical device, for example, a pair of binoculars, is provided with a tremble preventing apparatus for performing a tremble preventing operation by which a tremble of a focused image, due to a hand tremble and so on, is corrected. The tremble preventing apparatus includes correcting optical systems. When the tremble of the focused image occurs due to hand tremble, the correcting optical systems are driven from a position, at which optical axes of the correcting optical systems are respectively coaxial with optical axes of other optical systems of the optical device, in a direction and by an amount such that a movement of the optical device is canceled, so that the tremble of the focused image is corrected. Note that the position is referred to as a “moving center position” hereinafter. In the optical device, the correcting optical systems are initialized at the moving center position, before starting the aforementioned tremble preventing operation.
For initialization, the correcting optical systems are driven to the moving center position after a supply of a power is started and before a tremble preventing switch, for starting and stopping the tremble preventing operation, is turned ON. The driving of the correcting optical systems to the moving center position is not performed when the supply of the power is stopped.
If the optical device is a single-lens reflex camera, an object can be viewed through a finder while the power is not supplied. Namely, there is a problem that an actual object image viewed by a user does not coincide with a theoretical (desired) object image that lies on an optical axis of a lens barrel of the single-lens reflex camera.
Further, there is a telescope or a pair of binoculars including the above-mentioned tremble preventing apparatus. Such an optical device is provided with a single switch for both a power switch and a tremble preventing switch. When the optical device is mounted on a tripod and so on, it can be used with the tremble preventing switch, namely the power switch, being OFF, as the tremble does not occur. Accordingly, there is a problem that an actual object image viewed through the eyepiece(s) does not coincide with a theoretical (desired) object image that lies on an optical axis of a lens barrel of the optical device.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide an optical device by which an actual object image coincide with a theoretical (desired) object image that lies on an optical axis of a lens barrel.
In accordance with an aspect of the present invention, there is provided an optical device, provided with a tremble preventing function, comprising: a detector that detects an amount of an optical device tremble; a correcting optical system that corrects a tremble of a focused image due to the optical device tremble; and a driving system that drives the correcting optical system in two directions on a plane perpendicular to an optical axis of the correcting optical system, such that the optical device tremble amount is canceled when a tremble preventing operation is performed, and the driving system maintains a position of the correcting optical system when a power supply to the optical device is stopped.
The correcting optical system is driven to a moving center position such that the optical axis of the correcting optical system coincides with an optical axis of another optical system of the optical device, when the power supply to the optical device is stopped.
The optical device further comprises a reset position detector that detects whether the correcting optical system is positioned at a reset position at which the optical axis of the correcting optical system is substantially coaxial with the optical axis of another optical system. The correcting optical system is driven to the reset position, before being driven to the moving center position.
The optical device further comprises a memory system that stores difference data indicating a difference between the reset position and the moving center position.
The correcting optical system is driven to the moving center position based on a comparison of the reset position detector and the difference data.
Preferably, the memory system is an erasable and programmable nonvolatile memory.
Each of the two directions has the reset position detector, and the difference data of each of the two directions is stored in the memory system.
The reset position detector comprises: a photo-interrupter that includes a light-emitting element and a photoreceptor element; and a thin plate. A change of positional relationship between the photo-interrupter and the thin plate is detected based on, whether a luminance flux, outputted from the light-emitting element, is inputted to the photoreceptor element, or whether an amount of the luminance flux inputted to the photoreceptor element changes.
Preferably, the photo-interrupter is a transmission-type photo-interrupter in which the light-emitting element and the photoreceptor element are disposed facing each other separated by a predetermined interval, and the thin plate is interposed between the light-emitting element and the photoreceptor element.
Preferably, the photo-interrupter is a reflection-type photo-interrupter in which the light-emitting element and the photoreceptor element are disposed such that a light emitting surface of the light-emitting element and a light receiving surface of the photoreceptor element face substantially a same direction, and the thin plate faces the light emitting surface and the light receiving surface.
Optionally, the thin plate is immovably fixed, and the photo-interrupter moves in accordance with the driving of the correcting optical system. Further, optionally, the photo-interrupter is immovably fixed, and the thin plate moves in accordance with the driving of the correcting optical system.
The driving system comprises: a motor that is mounted in a motor case; and a shaft that moves in a longitudinal direction thereof, in accordance with a rotational direction of the motor, to move the correcting optical system. A thread is formed on the shaft, and a female thread, that securely engages the shaft thread, is formed on an inner wall of the motor case, the motor being unable to rotate due to the secure engagement when the power supply to the optical device is stopped, so that the correcting optical system is fixedly disposed at the moving center position.
The optical device further comprises a tremble preventing switch which starts and ends the tremble preventing operation. The correcting optical system is driven to the moving center position, when the tremble preventing switch is turned OFF.
In accordance with an aspect of the present invention, an optical device provided with a tremble preventing function, comprises: a detector that detects an amount of an optical device tremble; a correcting optical system that corrects a tremble of a focused image due to the optical device tremble; and a driving system that drives the correcting optical system two-dimensionally on a plane perpendicular to optical axis of the correcting optical system.
The optical axis of the correcting optical system actually coincides with an optical axis of another optical system of the optical device, when a power supply to the optical device is stopped.
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Hirunuma Ken
Tsukamoto Shinji
Asahi Kogaku Kogyo Kabushiki Kaisha
Greenblum & Bernstein P.L.C.
Le Que T.
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