Data-imprinting optical system for camera
AssigneeFuji Photo Optical Co., Ltd.
InventorKazunori Ohno
Life of this patent
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Abstract
There is described a data-imprinting optical system for use with a camera which is composed of a single meniscus lens having a positive refracting power and a brightness aperture, which can be applied to a low-cost unsophisticated camera of manual advance type by satisfying predetermined conditional equations, and which enables miniaturization of and space-saving in a camera. Specifically, the data-imprinting optical system includes a single positive meniscus lens and a brightness aperture disposed on the part of a data display member. The positive meniscus lens is a plastic lens having an aspherical concave surface on the part thereof facing the data display member. An image of display information appearing on the data display member is projected on a film surface.
Claims9
An optical system which imprints, onto a film surface, data appearing on a photographing information/data display member located on an objective side relative to the film surface and which is separate from a photographing lens, wherein
- the optical system comprises one meniscus lens having a positive refractive power and a brightness aperture and satisfies conditional expressions (1) through (3) provided below:
- 3.9≦L/F<5.0 (1)
- 0.02<D1/F<0.10 (2)
- −0.5<R3/F<−0.2 (3)
- where,
- L:
- is a distance from the photographing data display member to the film surface along an optical axis of a photographing lens,
- F:
- is a focal length of the meniscus lens,
- D1:
- is a distance from an aperture to the surface of the meniscus lens facing the aperture along the optical axis of the data-imprinting optical system, and
- R3:
- is a radius of curvature of the surface of the meniscus lens opposite that facing the aperture.
Dependencies are inferred from the claim text.