Photography – With exposure objective focusing means – focusing aid – or... – Having viewfinder
Reexamination Certificate
2002-04-25
2003-07-01
Adams, Russell (Department: 2851)
Photography
With exposure objective focusing means, focusing aid, or...
Having viewfinder
C396S271000, C396S296000, C396S382000, C396S386000, C396S377000
Reexamination Certificate
active
06587644
ABSTRACT:
This application claims benefit of Japanese Applications No. H11-359500 filed on Dec. 17, 1999, No. H11-359501 filed on Dec. 17, 1999, No. H11-359502 filed on Dec. 17, 1999, and No. H11-359503 filed on Dec. 17, 1999, the contents of which are incorporated by this reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a finder unit, and more particularly to a finder unit, having a finder optical system, for verifying and observing a field-of-view range containing a desired photographic image, in a camera or the like for taking pictures or the like.
2. Description of the Related Art
Various real-image type finder units have been proposed, as in Japanese Patent Application Laid-Open No. H10-10440/1998, for example, and made generally practical, which are finder units for verifying and observing a field-of-view range containing a desired viewing image, in a camera or the like for taking pictures or the like, that have a finder optical system configured by an objective optical system, inverting optical system, and eyepiece optical system, configured such that the viewing image formed by the objective optical system is made an erecting normal image by the inverting optical system, and enlarged for viewing by the eyepiece optical system.
The finder optical system of the finder unit disclosed in Japanese Patent Application Laid-Open No. H10-10440/1998 is made so that, by displacing the interval between the image formation position of the viewing image formed by the objective optical system and the condenser lens close to the eyepiece optical system by a prescribed distance (more than approximately 4 diopters (1/m)), the dust, grime, and scratches on the surface, etc., of the condenser lens and the dust and the like inside the prism will not be observed. This [finder optical system] is thus such that a good viewing image can be obtained.
Nevertheless, in the finder unit disclosed in Japanese Patent Application Laid-Open No. H10-10440/1998 (published), although it is possible to make the configuration such that dust and grime and the like adhering to the surface of the optical components (condenser lens) on the eyepiece optical system side that is in opposition to the viewing image formation position are not observed, there is no mention whatever of the similar problem in the optical components of the objective optical system in opposition to that image formation position.
Meanwhile, for conventional real-image type finder units such as described above which comprise a visibility adjustment mechanism wherewith the user of the unit can adjust the viewing visibility of the finder optical system at his or her discretion, various proposals have been made in the past, such as for means configured so that the viewing visibility can be altered by moving at least one optical component (specifically, the eyepiece lens, etc., configuring part of the eyepiece optical system) of the finder optical system, and these have been made generally practical.
However, when consideration is given to employing, in the finder optical system of the finder unit disclosed in Japanese Patent Application Laid-Open No. H10-10440/1998 (published), noted earlier, a visibility adjustment mechanism wherewith the viewing visibility is adjusted by moving the eyepiece lens, the problems discussed below are encountered.
That is, in the finder optical system of the finder unit disclosed in Japanese Patent Application Laid-Open No. H10-10440/1998 (published), the arrangement of the [configuring] members is set so that the interval between the image formation position for the viewing image formed by the objective optical system and the condenser lens close to the eyepiece optical system is displaced a prescribed distance.
In the finder unit of Japanese Patent Application Laid-Open No. H10-10440/1998 (published) noted above, when the configuration is made so that the interval between the image formation position of the viewing image and the condenser lens is displaced by approximately 4 diopters (1/m), it is possible to view a viewing image that is appropriate to a person with normal vision. However, when used in this condition by a near-sighted or far-sighted person, it is not possible to view an appropriate viewing image.
That being so, consideration is given to providing a visibility adjustment mechanism wherewith appropriate viewing images can be viewed with the same unit by various individuals having respectively different visual acuity. Then, when this is used to move the eyepiece lens of the finder optical system in the direction of the optical axis of the finder optical system, by prescribed means, it becomes possible to adjust the viewing visibility. Thereupon, when a far-sighted person, for example, has used the visibility adjustment mechanism to adjust the viewing visibility so as to be appropriate for himself or herself, the eyepiece lens will be set in a position that is distanced from the viewing image as compared to the position at which a person of normal vision views. Accordingly, should a person of normal vision view a viewing image in this condition, as is, without making a readjustment, it is possible that he or she would be able to observe the dust and grime, etc., adhering to the surface, etc., of the condenser lens.
In other words, there is a problem in that, even when the means disclosed in Japanese Patent Application Laid-Open No. H10-10440/1998 (published) are augmented by a visibility adjustment mechanism, there is no guarantee that it will always be possible to obtain a good viewing image.
Other conventional real-image type finder units are also disclosed, as, for example, in Japanese Patent Application Laid-Open No. H10-307315/1998 (published).
The finder unit disclosed in Japanese Patent Application Laid-Open No. H10-307315/1998 (published) is a so-called bright-frame-finder unit that is configured by a plurality of optical elements, wherein, by deploying a translucent reflecting surface at a prescribed position in the light path of the finder optical system, means for displaying various kinds of information relating to photographing that are superimposed on the viewing image of a desired photographic subject, such as, for example, field of view frame information for-defining the field of view constituting the photographic range, or field of view information for displaying camera settings and operating conditions and the like in a form that can be visually distinguished (hereinafter called in-finder display), are deployed separately from the finder optical system.
In the configuration of the finder unit disclosed in the publication just cited, furthermore, light measuring means for performing light measuring operations for automatically setting the exposure are provided, and light flux division means are provided for making it possible to guide the light flux guided into the interior of the finder unit for those light measuring means and for the means for making the in-finder display described above, respectively. Thus it becomes possible, while viewing the viewing image of the photographic subject, to execute a prescribed light measuring operation using light flux equivalent to the light flux forming that viewing image and to set the exposure at the time of the shooting.
In general, in a bright-frame-finder unit, a display panel is used as means for effecting various kinds of displays in the finder, but this display panel must be deployed at a position that is substantially optically equivalent relative to the positional relationship between the eyepiece optical system and the image formation position of the viewing image formed by the objective optical system.
Based on the means disclosed in Japanese Patent Application Laid-Open No. H10-307315/1998 (published) noted earlier, however, in view of the fact that the configuration is such that there is a plurality of reflecting surfaces between the eyepiece optical system and the image formation position of the viewing image formed by the objective optical system, it is necessary to secure a lon
Kato Shigeru
Sugita Yukihiko
Takahashi Shinya
Takase Masami
Adams Russell
Blackman Rochelle Ann J
Frishauf Holtz Goodman & Chick P.C.
Olympus Optical Co,. Ltd.
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