Anti-ghost device for optical distance measuring system
AssigneeCanon Kabushiki Kaisha
InventorsHideo Yokota, Kazuya Hosoe
Life of this patent
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Abstract
In the disclosed optical distance measuring system, a pair of mirrors spaced from each other along a base line direct light coming from a scene along two optical paths onto reflecting surfaces of a prism positioned between them and through a pair of image forming lenses positioned between the prism and the mirrors so that the prism forms images of the scene on respective photoelectric element arrays. A light baffle in front of the photoelectric element arrays forms an aperture for limiting a desired field of view and includes a light shading projection at the edge of the aperture for preventing light rays from the lenses and outside the desired field of view from impinging upon the arrays.
Claims7
An optical distance measuring system comprising:
- first and second electro-optical arrays positioned adjacent each other;
- a prism having a pair of reflecting faces angular to each other and forming a bisecting plane transverse to the arrays and between the arrays;
- a pair of lenses positioned along an optical axis transverse to the bisecting plane on opposite sides of the bisecting plane;
- a plane of mirrors for collecting light along directions substantially transverse to the optical axis and positioned on opposite sides of the respective lenses so as to direct light through the lenses to the faces of said prism for reflecting toward said arrays;
- said arrays being spaced closer to said faces than said lenses;
- and
- a pair of opaque elements on opposite sides of the plane having first portions extending parallel to the arrays and transverse to said plane and having angular extensions projecting toward said faces so as to block light from said lenses toward said arrays.
An optical measuring system, comprising:
- a pair of spaced mirrors for directing light from a scene toward each other,
- means having a pair of reflecting surfaces between said mirrors for directing light from the mirrors along substantially parallel paths,
- a pair of electro-optical devices, each device of said pair being located in one of the paths,
- view field defining means positioned between the reflecting surfaces and the devices for limiting the field of view from the reflecting surfaces to the devices,
- said view field defining means having an aperture and a pair of projections each for preventing light from one of the mirrors from striking the one of the devices more remote from the one of the mirrors.
Dependencies are inferred from the claim text.