Ophthalmic instrument
First Claim
1. An ophthalmic instrument comprising:
- measurement means for measuring a subject eye;
an optical alignment system having index projection means which projects index light onto a cornea of said subject eye and light receiving means which receives reflected light of said index light reflected at said cornea; and
arithmetic means for computing a positional relation between a body of said ophthalmic instrument and said cornea, based on a position of an index image formed on a light receiving surface of said light receiving means;
wherein said optical alignment system is provided with light quantity reducing means which has a transmittance distribution characteristic in which a quantity of light is gradually reduced from an optical axis in a radial direction.
1 Assignment
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Accused Products
Abstract
Disclosed herein is an ophthalmic instrument equipped with an optical alignment system. The optical alignment system has a Z-alignment index projection light system (60) which projects index light onto the cornea (C) of a subject eye (E) and a sensor (73) which receives reflected light of the index light reflected at the cornea (C). The ophthalmic instrument is further equipped with a Z-alignment detection circuit (74) which computes a positional relation between an index image formed on a light receiving surface of the sensor (73) and the cornea (C). When the result of computation by the detection circuit (74) is within a predetermined range, the subject eye is measured. The Z-alignment index projection light system (60) is provided with an aperture diaphragm (63) which has a transmittance distribution characteristic in which a quantity of light is gradually reduced from the optical axis of the system (60) in a radial direction.
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Citations
6 Claims
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1. An ophthalmic instrument comprising:
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measurement means for measuring a subject eye; an optical alignment system having index projection means which projects index light onto a cornea of said subject eye and light receiving means which receives reflected light of said index light reflected at said cornea; and arithmetic means for computing a positional relation between a body of said ophthalmic instrument and said cornea, based on a position of an index image formed on a light receiving surface of said light receiving means; wherein said optical alignment system is provided with light quantity reducing means which has a transmittance distribution characteristic in which a quantity of light is gradually reduced from an optical axis in a radial direction. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification