초록 ▼

A focus detecting optical system including a condenser lens disposed in a vicinity of or rearwardly of a predetermined focal plane of a photographic lens, an image forming lens unit having a pair of image forming lens sections disposed symmetrically relative to a main optical axis, a light blocking

A focus detecting optical system including a condenser lens disposed in a vicinity of or rearwardly of a predetermined focal plane of a photographic lens, an image forming lens unit having a pair of image forming lens sections disposed symmetrically relative to a main optical axis, a light blocking member having an opening for regulating a luminous flux coming into the image forming lens unit, a first prism for refracting the luminous flux in a direction departing from the main optical axis, a second prism for refracting the luminous flux in a direction nearing the main optical axis and a light receiving element array. An image formed on the light receiving element array and formed of the luminous flux carried through the condenser lens, the first prism, one of the image forming lens sections and the second prism and an image formed on the light receiving element array and formed of the luminous flux carried through the condenser lens, the first prism, the other image forming lens section and the second prism are placed with a sufficient distance therebetween by working of the first and second prisms. A focus detecting operation is carried out by comparing these images.

대표청구항 ▼

A focus detecting optical system, comprising: a condenser lens disposed in a vicinity of or rearwardly of a predetermined focal plane of a photographic lens; image forming lens means disposed rearwardly of said condenser lens and including a pair of image forming lens sections disposed symmetrically

A focus detecting optical system, comprising: a condenser lens disposed in a vicinity of or rearwardly of a predetermined focal plane of a photographic lens; image forming lens means disposed rearwardly of said condenser lens and including a pair of image forming lens sections disposed symmetrically relative to a main optical axis; a light blocking member disposed forwardly of said image forming lens means and having an opening for regulating a luminous flux coming into said image forming lens means; first prism means disposed between said image forming lens means and said light blocking member and adapted for refracting the luminous flux in a direction departing from the main optical axis; second prism means disposed rearwardly of said first prism means and adapted for refracting the luminous flux in a direction towards the main optical axis; and a light receiving element array disposed rearwardly of said second prism means, said light receiving element array having formed thereon images by said image forming lens means; whereby a focus detecting operation is carried out by comparing one of the images formed on said light receiving element array and formed of the luminous flux carried through said condenser lens, said first prism means, one of said image forming lens sections and said second prism means with the other of the images formed on said light receiving element array and formed of the luminous flux carried through said condenser lens, said first prism means, the other of said image forming lens sections and said second prism means.