OPHTHALMOLOGIC APPARATUS AND METHOD FOR CONTROLLING THE SAME

• US 20140146287A1
• Filed: 11/22/2013
• Published: 05/29/2014
• Est. Priority Date: 11/26/2012
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Ota, Yuji
• Granted Patent: US 9,706,919 B2
• Time in Patent Office: Days
• US Class Current: 351/206
• CPC Class Codes: A61B 3/0008 provided with illuminating means A61B3/117 takes precedence; goniolenses used for laser treatment A61F9/009; illuminating means for optical instruments G02B27/00
• CPC Class Codes: A61B 3/0091 Fixation targets for viewing direction
• CPC Class Codes: A61B 3/12 for looking at the eye fundus, e.g. ophthalmoscopes A61B3/13 takes precedence
• CPC Class Codes: A61B 3/14 Arrangements specially adapted for eye photography apparatus or arrangements for taking photographs per se G03B
• CPC Class Codes: A61B 3/152 for aligning

Abstract

An ophthalmologic apparatus includes a photographing optical system configured to photograph a fundus of a subject'"'"'s eye via a focusing lens, a projection unit configured to project, via a mask portion including an opening, a focusing index corresponding to the opening, and a driving unit configured to drive the focusing lens along an optical path based on a position of an image corresponding to the mask portion and a position of a focusing index image corresponding to the opening in a fundus image of the subject'"'"'s eye.

Claims

1. An ophthalmologic apparatus comprising:

a photographing optical system configured to photograph a fundus of a subject'"'"'s eye via a focusing lens;

a projection unit configured to project, via a mask portion including an opening, a focusing index corresponding to the opening; and

a driving unit configured to drive the focusing lens along an optical path based on a position of an image corresponding to the mask portion and a position of a focusing index image corresponding to the opening in a fundus image of the subject'"'"'s eye.

2. The ophthalmologic apparatus according to claim 1, wherein the driving unit is configured to drive, when there is a plurality of focusing indices in the fundus image of the subject'"'"'s eye, the focusing lens along the optical path so that a predetermined positional relationship is set among the plurality of focusing indices in the fundus, and

wherein the driving unit is configured to drive, when there is one focusing index in the fundus image, the focusing lens along the optical path based on the position of the image corresponding to the mask portion and the position of the focusing index image corresponding to the opening in the fundus image of the subject'"'"'s eye.

3. The ophthalmologic apparatus according to claim 2, wherein when the fundus of the subject'"'"'s eye and the projection unit are optically conjugate with each other, the predetermined positional relationship is set among the plurality of focusing indices in the fundus.

4. The ophthalmologic apparatus according to claim 1, wherein the driving unit is configured to change a position of the projection unit in conjunction with a position of the focusing lens.

5. The ophthalmologic apparatus according to claim 1, further comprising an illumination optical system configured to illuminate the fundus of the subject'"'"'s eye,

wherein the projection unit is disposed to be insertable into and detachable from an optical path of the illumination optical system.

6. The ophthalmologic apparatus according to claim 1, wherein when there is one focusing index in the fundus image of the subject'"'"'s eye, illuminance of illuminating the projection unit is higher than that when there is a plurality of focusing indices in the fundus image.

7. The ophthalmologic apparatus according to claim 1, wherein the driving unit is configured to drive the focusing lens along the optical path based on the position of the image corresponding to the mask portion and the position of the focusing index image corresponding to the opening in the fundus image of the subject'"'"'s eye so that the projection unit and an imaging unit in the photographing optical system become approximately conjugate with each other.

8. The ophthalmologic apparatus according to claim 1, wherein the projection unit includes a prism having prism planes of angles symmetrical to each other arranged at the opening of the mask portion, and

wherein light fluxes transmitted through the prism planes pass through the rectangular opening of the mask portion and are projected as a plurality of focusing indices onto the fundus.

9. The ophthalmologic apparatus according to claim 1, further comprising a focusing control unit configured to extract a region of the mask portion of the focusing index and a position of the focusing index from the fundus image, and to output a driving signal to the driving unit based on a positional relationship between the extracted region and position.

10. The ophthalmologic apparatus according to claim 9, wherein the focusing control unit is configured to extract the region of the mask portion of the focusing index and the position of the focusing index from the fundus image, and to output the driving signal to the driving unit so that a center of the opening for projecting the focusing index of the mask portion and the position of the focusing index coincide with each other.

11. A method for controlling an ophthalmologic apparatus that includes a photographing optical system configured to photograph a fundus of a subject'"'"'s eye via a focusing lens and a projection unit configured to project, via a mask portion including an opening, a focusing index corresponding to the opening, the method comprising:

driving the focusing lens along an optical path based on a position of an image corresponding to the mask portion and a position of a focusing index image corresponding to the opening in a fundus image of the subject'"'"'s eye.

12. The method according to claim 11, further comprising:

driving, when there is a plurality of focusing indices in the fundus image of the subject'"'"'s eye, the focusing lens along the optical path so that a predetermined positional relationship is set among the plurality of focusing indices in the fundus; and

driving, when there is one focusing index in the fundus image, the focusing lens along the optical path based on the position of the image corresponding to the mask portion and the position of the focusing index image corresponding to the opening in the fundus image of the subject'"'"'s eye.

13. A computer-readable storage medium storing a program that causes a computer to perform the method according to claim 11.