Patent
1994-10-18
1996-06-11
Perkey, W. B.
G03B 1302
Patent
active
055260829
ABSTRACT:
An automatic visibility regulator for a camera viewfinder includes a focusing detector system that is adapted to detecting whether or not an object image to be photographed, having passed through the viewfinder, is focused on the retina of the user's eyeball and a focal position shifting device adapted to shifting a focal position of an ocular system and thereby to shift a position at which the object image is focused. The focal position shifting device is actuated to shift the ocular system when the focusing detector system detects that the object image is not focused on the retina of the user's eyeball. The focal position shifting device is not actuated, and, consequently, the focal position of the ocular system is not changed, when the focusing detector system detects that the object image is focused on the retina. The focusing detector system includes a combination of a photo projector and a photodetector, wherein a beam of light projected from the projector passes through the ocular system and is reflected on the retina of the user's eyeball. The beam of light passes again through the ocular system and is received by the photodetector. Properties of the received beam of light determine whether or not the object image is focused on the retina. If it is determined that the object image is not focused on the retina, the focal position shifting device is actuated to shift the focal position of the ocular system until the object image is focused on the retina. In this manner, visibility is automatically adjusted to an appropriate value without any adjustment operation by user.
REFERENCES:
patent: 741102 (1903-10-01), Borsum
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patent: 5255033 (1993-10-01), Dassero
patent: 5335030 (1994-08-01), Suzuka
Pending U.S. patent application Ser. No. 08/302,049, filed Sep. 7, 1994, entitled Viewfinder Arrangement In Photographic Camera, filed by Tsuyuki et al.
Fuji Photo Optical Co., Ltd.
Perkey W. B.
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