Photography – Flash system responsive to focal length or distance – Illumination angle responds to focal length or distance
Reexamination Certificate
2001-07-06
2002-12-17
Perkey, W. B. (Department: 2851)
Photography
Flash system responsive to focal length or distance
Illumination angle responds to focal length or distance
Reexamination Certificate
active
06496650
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a camera with a flash unit in which the flash unit is moved by utilizing a lens-barrel driving motor which is for moving a taking lens.
2. Description of the Related Art
Conventionally, it is known that some compact zoom cameras have a flash-angle changing mechanism by which a flash angle of a flash unit is changed. As to the flash-angle changing mechanism, there are some types. In one of the types, an angle of a reflection member is changed. In another type, distances from an optical panel to a discharge tube and a reflector are changed. The optical panel is a diffusion plate or a condenser plate, for example.
It is necessary to adjust the flash angle to a photographic angle of view. In the case of the zoom camera, the flash angle is consecutively changed in association with a change of the photographic angle of view. Changing the flash angle is performed by utilizing a magnification varying motor which moves a taking lens in an optical axis direction at the time of varying the magnification. A rotation of the magnification varying motor is transmitted to a viewfinder as well to be used as a driving force for shifting a visual field of the viewfinder.
There are some ways for transmitting the driving force of the magnification varying motor to the flash-angle changing mechanism. In one of the ways, the driving force is directly transmitted from the magnification varying motor. In another way, the driving force is transmitted via a lens guiding mechanism which moves the taking lens in the optical axis direction. In the other way, the driving force is transmitted via the viewfinder. Meanwhile, the general camera includes a film containing chamber and a cartridge containing chamber respectively arranged at both sides of an exposure aperture. The viewfinder is disposed above a lens barrel. A zoom flash unit is separated from the taking lens as far as possible and is disposed above the film containing chamber or the cartridge containing chamber, in order to reduce red-eye effect.
In consideration of the above background, a mechanism for transmitting the driving force to the zoom flash unit must be constructed in any event such that the driving force is led from a front side of the camera to an above portion of either of the film containing chamber and the cartridge containing chamber via a periphery thereof. However, as the zoom camera becomes compact, its inside space is also downsized. When the mechanism for transmitting the driving force to the zoom flash unit is constructed only by gear trains, transmitting the driving force is efficiently performed, whereas this mechanism is difficult to be adopted because of a space for arranging plenty of gears. Meanwhile, when the transmitting mechanism employs an endless belt or an endless rubber band, a space and a number of parts may be reduced. In this case, however, the flash angle is likely to be shifted relative to a magnification position of the taking lens due to a slip. Thus, such a mechanism is also difficult to be adopted.
Moreover, regarding the route from the front side of the camera to the above portion of either of the film containing chamber and the cartridge containing chamber, it is necessary to provide a mechanism for changing a transmission direction crosswise by at least one time. As to such a mechanism, it is well known to use gears of an intersecting axis and a hyperboloidal axis, for example, a worm gear and a bevel gear. However, in case these gears are employed, assembly thereof is difficult. At the same time, a contact load of the gears is great so that it is necessary to use the magnification varying motor having large torque. Thus, there arises a problem in that the cost increases.
By the way, there is a type in which a flash unit is popped up from a retracted position to a flash-photographing position in association with the lens barrel moving from a collapsible-mount position to a photographing position. The flash unit is contained in the camera when kept in the retracted position, and emerges to the outside when kept in the flash-photographing position. This type has a problem similar to the above with respect to a mechanism for transmitting a driving force of a lens-barrel moving motor to the flash unit.
SUMMARY OF THE INVENTION
In view of the foregoing, it is a primary object of the present invention to provide a camera with a built-in flash unit in which a mechanism for transmitting a driving force of a motor to the flash unit is efficiently arranged in a small space.
It is a second object of the present invention to provide a camera with a built-in flash unit in which a mechanism for transmitting a driving force of a motor to the flash unit is easily assembled.
It is a third object of the present invention to provide a camera with a built-in flash unit in which a mechanism for transmitting a driving force of a motor to the flash unit has an advantage regarding its cost.
In order to achieve the above and other objects, the camera with the built-in flash unit according to the present invention comprises a driving-force transmission mechanism including a gear train and a rack plate.
The gear train is disposed in front of a camera main body and is rotated by a driving force of a motor which is used for moving a lens barrel to vary a magnification. The rack plate is disposed at a side of the camera main body so as to be movable in a vertical direction. The driving force of the motor is transmitted to the flash unit via the gear train and the rack plate to change a flash angle of the flash unit in accordance with a focal length of a taking lens.
In a preferred embodiment, the gear train is disposed in front of a film containing chamber of the camera main body, and the rack plate is disposed at a right side of the film containing chamber. The rack plate is provided with rack teeth meshing with an output gear of the gear train. A portion of the rack teeth is bent so as to be located in front of the film containing chamber.
According to the present invention, the driving force of the motor is easily and efficiently transmitted crosswise from the front of the film containing chamber to the right side thereof. Moreover, assembly of the driving-force transmission mechanism is easy. Further, rotating the gear train and moving the rack plate are respectively performed in a plane parallel with an outer wall of the film containing camber. Thus, the driving-force transmission mechanism is easily disposed in a small space formed between the film containing chamber and a cover of the camera. Hence, the camera may be downsized.
Incidentally, the gear train and the rack plate may be respectively disposed at the front and the right of a cartridge containing chamber instead of the film containing chamber.
REFERENCES:
patent: 4944030 (1990-07-01), Haraguchi et al.
patent: 5083146 (1992-01-01), Ueda
Fuji Photo Optical Co., Ltd.
Perkey W. B.
Young & Thompson
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