Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Reexamination Certificate
2001-03-15
2002-12-17
Manuel, George (Department: 3737)
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
Reexamination Certificate
active
06494577
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ophthalmologic apparatus for obtaining information inherent in an eye of a patient, such as information relating to eye refractive power, eye fundus image, and volume of eye fundus blood flow.
2. Related Background Art
In this type of an ophthalmologic apparatus, before an examination, it is necessary to perform positioning (alignment) of an examination unit to an eye of a person to be examined (patient). This alignment is performed as follows. An operator observes an anterior eye part image of a patient displayed on a display unit, and operates an operation device to rough align an examination unit with an eye. After a cornea reflected image or a pupil image due to an index light flux projected to an cornea of the eye is displayed on the display unit, the operator operates the operation device such that the cornea reflected image or the pupil image is aligned with a mark for alignment displayed around an optical axis, whereby exact alignment is performed. In this ophthalmologic apparatus, an acceptable range with respect to alignment between a standard position of the eye and an optical axis of the examination unit is related to an acceptable degree of deviation in a measurement value due to change in a position of the examination unit, whereby an alignment acceptable range, that is, a measurement acceptable area is determined.
Recently, a method for performing automatic alignment of the examination unit to be actuated by an actuator has been proposed. In this method, a reflected index image from the eye is detected photoelectrically, and the actuator is controlled so as to align an optical axis of the examination unit with the detected reflected index image. Here, there are a method for controlling the actuator continuously after the standard position of the eye enters the measurement acceptable area, a method for stopping control of the actuator when the standard position of the eye enters the measurement acceptable area and restarting control of the actuator when the standard position of the eye is apart from the measurement acceptable area, and the like. However, in the former method, even if the apparatus is in the state where a measurement value is obtained with a high precision, the actuator may be repeatedly controlled more than necessary. This prevents rapid measurement. On the other hand, in the latter method, when the standard position of the eye is located in an end of the measurement acceptable area and thus control of the actuator is stopped, the standard position of the eye may be apart from the measurement acceptable area in accordance with slight movement of the eye. This prevents stable measurement.
Here, although a degree is different depending on personal equation or disease factor, it is known that a vertex of the cornea is eccentric to the center of the pupil in most of the human eyes. Thus, when exact alignment of the apparatus and the eye is performed to the center of the index image, the pupil is eccentric to a light ring, whereby a light flux necessary for measurement may be shaded by the pupil. This prevents stable measurement.
Commonly, a radius of the pupil in the eye of the human becomes larger or smaller by accommodation of eye function. Thus, it is required that an operator is in practice with respect to alignment between the pupil and the apparatus examination unit. Also, in the apparatus for automatic alignment, since complicated processing is necessary to detect the center of the pupil photoelectrically, it takes a long time, whereby preventing the rapidity of measurement.
SUMMARY OF THE INVENTION
The present invention is started from the above attention. One object of the present invention is to provide an ophthalmologic apparatus in which stable measurement can be performed rapidly. Another object of the present invention is to provide an ophthalmologic apparatus in which simplification and miniaturization can be attained.
To attain the above object, according to one aspect of the present invention, there is provided an ophthalmologic apparatus comprising:
a measuring system for measuring inherent information of an eye;
a detecting system for detecting a standard position of the eye;
an actuator for actuating an optical system including the measuring system and the detecting system; and
a controller for dividing a processing procedure of alignment between the standard position of the eye and the measuring system in accordance with each of a plurality of areas, and changing a control method for at least one of the measuring system and the actuator in accordance with an area in which the standard position is located.
In the aspect of the invention, there may be provided an ophthalmologic apparatus, further comprising an light source for measurement and index projection commonly, and an optical system for performing both pickup of an index image and observation of the eye.
In the aspect of the invention, there may be provided an ophthalmologic apparatus, wherein the controller controls to perform measurement by the measuring system plural times.
In the aspect of the invention, there may be provided an ophthalmologic apparatus, wherein the plurality of areas have a first area which is a measurement acceptable area of a relative position between the standard position and the measuring system, a second area which is within the first area and is smaller than the first area, and a third area which is outside the first and second areas, and
the controller has a first step of determining that the standard position is within which of the first, second and third areas, a second step of controlling the actuator so as to enter the standard position into the second area, and a third step of allowing measurement, and performs the second and third steps when the standard position is within the first area in the first step, performs the third step when the standard position is within the second area in the first step, and performs the second step when the standard position is within the third area in the first step.
In the aspect of the invention, there may be provided an ophthalmologic apparatus, wherein the detecting system has a system for projecting an index light flux for alignment and dividing the index light flux reflected from the eye into a plurality of light flux.
In the aspect of the invention, there may be provided an ophthalmologic apparatus, further comprising a display for displaying the eye with the plurality of areas.
In the aspect of the invention, there is provided an ophthalmologic apparatus, wherein the controller controls to start measurement automatically when the standard position of the eye is within the processing procedure.
According to other aspect of the present invention, there is provided an ophthalmologic apparatus comprising:
a measuring system for measuring inherent information of an eye;
an index system for projecting an index light flux onto a cornea of the eye;
an image pickup device for picking an anterior eye part of the eye together with an index image of an index light flux reflected from the cornea;
a display for displaying an anterior eye part image picked by the image pickup device together with the index image;
an operation device for allowing an operator to operate; and
a controller for detecting a position of the index image in accordance with operation by the operation device, and performing control to display an alignment mark representing a position of the index image around the index image on the display.
In the aspect of the invention, there may be provided an ophthalmologic apparatus, further comprising an indicator for indicating to the operator whether the index image is within an area represented by the alignment mark or not.
In the other aspect of the invention, there may be provided an ophthalmologic apparatus, wherein the controller determines whether the index image is within an area represented by the alignment mark or not, and controls to automatically repeat measurement executed by the measuring system pre
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Manuel George
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