Eye refractometer

Claim 2

An eye refractometer comprising: a projection optical system including a light source for projecting a bundle of light rays and an objective lens disposed opposite to an eye under test and means for forming said bundle of light rays into a ring-shaped pattern, said light source projecting said bundle of rays to the eye under test through said objective lens and said ring-shaped pattern forming means and onto a peripheral area of a pupil surface of the eye under test to form a ring-shaped pattern image at the retina of the eye under test; a light receiving optical system for receiving said ring-shaped pattern reflected from the retina onto a photo-electric detector through a central portion of said pupil; and means for determining the coordinates of said ring-shaped pattern image formed on said photo-electric detector relative to a predetermined coordinate system, and means for determining the refractivity of the eye under test in accordance with the determined coordinates of said image.

Claim 3

An eye refractometer according to claim 1, wherein said light source is disposed at a nearly conjugate position with respect to the eye under test, and said projection optical system further includes a deflection optical member disposed at a nearly conjugate position with respect to the pupil of the eye under test, said deflection optical member adapted to deflect the bundle of rays from said light source at a predetermined angle with respect to an optical axis of said eye under test.

Claim 4

An eye refractometer according to claim 1, wherein said means for forming a ring-shaped pattern comrpises a diaphragm member having a ring-shaped transmission opening portion formed therein.

Claim 5

An eye refractometer according to claim 1, wherein said means for forming a ring-shaped pattern includes a diaphragm member having a plurality of pin holes arranged in a ring-shape.

Claim 6

The eye refractometer of claim 1, wherein said means for forming a ring-shaped pattern of said bundle of light rays includes a mirror, said mirror having a central perforation therein for passing a portion of said reflected light rays therethrough and onto said photo-electric detector.

Claim 7

An eye refractometer comprising: a projection optical system, including a light source disposed at a position nearly conjugate to the eye under test, for projecting a bundle of light rays; an objective lens disposed opposite to an eye under test and means for forming said bundle of light rays into a ring-shaped pattern, said light source projecting said bundle of rays to the eye under test through said objective lens and said ring-shaped pattern forming means and onto a peripheral area of a pupil surface of the eye under test to form a ring-shaped pattern image at the retina of the eye under test; said projection optical system further including a prism having a conical reflective surface, said prism being disposed nearly conjugate to the pupil of the eye under test and being adapted to deflect said bundle of light rays at a predetermined angle with respect to an optical axis of the eye under test, said optical axis coinciding with a central axis of said conical reflective surface; a light receiving optical system for receiving a portion of said ring-shaped pattern reflected from the retina onto a photo-electric detector through a central portion of said pupil; and means for measuring the size and the configuration of said ring-shaped pattern image formed on said photo-electric detector and for determining the refractivity of the eye under test in accordance with the measured size and configuration of said image.

Claim 8

An eye refractometer comprising: a projection optical system, including a light source disposed at a position nearly conjugate to the eye under test, for projecting a bundle of light rays; an objective lens disposed opposite to an eye under test and means for forming said bundle of light rays into a ring-shaped pattern, said light source projecting said bundle of rays to the eye under test through said objective lens and said ring-shaped pattern forming means and onto a peripheral area of a pupil surface of the eye under test to form a ring-shaped pattern image at the retina of the eye under test; said projection optical system further including a prism having a conical reflective surface, said prism being disposed nearly conjugate to the pupil of the eye under test and being adapted to deflect said bundle of light rays at a predetermined angle with respect to an optical axis of the eye under test, said optical axis coinciding with a central axis of said conical reflective surface; a light receiving optical system for receiving a portion of said ring-shaped pattern reflected from the retina onto a photo-electric detector through a central portion of said pupil; and means for measuring the size and the configuration of said ring-shaped pattern image formed on said photo-electric detector and for determining the refractivity of the eye under test in accordance with the measured size and configuration of said image.

Claim 9

An eye refractometer comprising: a projection optical system, including a light source disposed at a position nearly conjugate to the eye under test, for projecting a bundle of light rays; an objective lens disposed opposite to an eye under test and means for forming said bundle of light rays into a ring-shaped pattern, said light source projecting said bundle of rays to the eye under test through said objective lens and said ring-shaped pattern forming means and onto a peripheral area of a pupil surface of the eye under test to form a ring-shaped pattern image at the retina of the eye under test; said projection optical system further including a prism having a multi-angle conical-shaped refractive surface, said prism being disposed nearly conjugate to the pupil of the eye under test and being adapted to deflect said bundle of light rays at a predetermined angle with respect to an optical axis of the eye under test, said optical axis coinciding with a central axis of said conical-shaped refractive surface; a light receiving optical system for receiving a portion of said ring-shaped pattern reflected from the retina onto a photo-electric detector through a central portion of said pupil; and means for measuring the size and the configuration of said ring-shaped pattern image formed on said photo-electric detector, and for determining the refractivity of the eye under test in accordance with the measured size and configuration of said image.

Claim 10

An eye refractometer comprising: a projection optical system, including a light source disposed at a position nearly conjugate to the eye under test, for projecting a bundle of light rays; an objective lens disposed opposite to an eye under test and means for forming said bundle of light rays into a ring-shaped pattern, said light source projecting said bundle of rays to the eye under test through said objective lens and said ring-shaped pattern forming means and onto a peripheral area of a pupil surface of the eye under test to form a ring-shaped pattern image at the retina of the eye under test; said projection optical system further including a prism having a multi-angle conical-shaped refractive surface, said prism being disposed nearly conjugate to the pupil of the eye under test and being adapted to deflect said bundle of light rays at a predetermined angle with respect to an optical axis of the eye under test, said optical axis coinciding with a central axis of said conical-shaped refractive surface; a light receiving optical system for receiving a portion of said ring-shaped pattern reflected from the retina onto a photo-electric detector through a central portion of said pupil; and means for measuring the size and the configuration of said ring-shaped pattern image formed on said photo-electric detector, and for determining the refractivity of the eye under test in accordance with the measured size and configuration of said image.