Eye fundus examining apparatus

• US 5,894,337 A
• Filed: 08/29/1997
• Issued: 04/13/1999
• Est. Priority Date: 09/03/1996
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Itoh, Hiroshi, Ono, Shigeaki, Tanaka, Shinya, Numajiri, Yasuyuki, Iwanaga, Tomoyuki, Okumura, Toshiaki, Okinishi, Satoru
• Primary Examiner(s): Manuel, George
• Application Number:
  US08/921,356
• Time in Patent Office: 592 Days
• Field of Search: 351/205, 351/206, 351/207, 351/208, 351/222, 351/214, 351/215, 351/246
• US Class Current: 351/205
• CPC Class Codes: A61B 3/1241 specially adapted for observation of ocular blood flow, e.g. by fluorescein angiography

Abstract

A eye fundus examining apparatus includes a first optical system for projecting measurement light onto the fundus of an eye, a deflecting member provided in the first optical system for deflecting the measurement light, a light receiving element for receiving the reflected light of the measurement light from the fundus of the eye, a predetermined parameter of a target on the fundus of the eye being measured from the light reception information of the light receiving element, a second optical system for projecting a tracking light beam to an area including the target on the fundus of the eye, an image pickup element for receiving the image of the target illuminated by the tracking light beam, and a control system for driving the deflecting member and directing the measurement light onto the target so that the distance of deviation from the illuminated point by the measurement light under an ideal condition on the fundus of the eye to the target image received on the image pickup element may become a set value, the set value being suitably resettable.

Claims

1. An eye fundus examining apparatus comprising:

a first optical system for projecting measurement light onto the fundus of an eye;

a deflecting member provided in said first optical system for deflecting said measurement light;

a light receiving element for receiving the measurement light reflected from the fundus of the eye, a predetermined parameter of a target on the fundus of the eye being measured from light reception information of said light receiving element;

a second optical system for projecting a tracking light beam to an area including said target on the fundus of the eye;

an image pickup element for receiving the image of said target illuminated by said tracking light beam; and

a control system for driving said deflecting member and directing said measurement light onto said target so that the distance of deviation from an illuminated point on the eye fundus illuminated by said measurement light under an ideal condition to said target image received on said image pickup element becomes a set value, said set value being suitably resettable.

2. An apparatus according to claim 1, wherein said measurement light and said tracking light beam are separable from each other due to their wavelengths.

3. An apparatus according to claim 1, wherein said control system has a detecting portion for detecting the distance of deviation from a tracking reference position on said image pickup element initially set at the conjugate position of the illuminated point on the eye fundus illuminated by said measurement light under the ideal condition to said target image received by said image pickup element, a directing system for driving said deflecting member so that the distance of deviation becomes zero, and directing said measurement light onto said target image, and tracking reference position correcting means for rendering said tracking reference position suitably movable and resettable.

4. An apparatus according to claim 1, further having changing means for changing the projection angle or the projected position of said measurement light on the incident side of said deflecting means.

5. An eye fundus examining apparatus comprising:

a light beam scanning system for deflecting a light beam in conformity with a control signal;

a light source emitting a tracking light beam;

a tracking light beam applying system for directing the tracking light beam from said light source to a measured portion of an eye to be examined through said light beam scanning system;

a beam power controlling portion for controlling the beam power of the tracking light beam provided in said tracking light beam applying system;

an imaging optical system for directing scattered reflected light of said tracking light beam scattered and reflected from the measured portion of the eye to be examined to a light receiving device through said light beam scanning system; and

a control system for controlling said light beam scanning system in conformity with the output from said light receiving device.

6. An apparatus according to claim 5, wherein said beam power controlling portion has an optical member partially differing in transmittance.

7. An eye fundus examining apparatus comprising:

a light beam scanning system for deflecting a light beam in conformity with a control signal;

a light source emitting a tracking light beam;

a tracking light beam applying system for directing the tracking light beam from said light source to a measured portion of an eye to be examined through said light beam scanning system;

a beam power controlling portion for controlling the beam power of the tracking light beam provided in said tracking light beam applying system;

an imaging optical system for directing scattered reflected light of said tracking light beam scattered and reflected from the measured portion of the eye to be examined to a light receiving device through said light beam scanning system; and

a control system for controlling said light beam scanning system and said beam power controlling portion in conformity with the output from said light receiving device.

8. An apparatus according to claim 7, wherein said beam power controlling portion has an optical member partially differing in transmittance.