Ophthalmic image sensing apparatus

Abstract

A focusing unit is constituted of a prism base, deflection prisms, and a slit chart having a slit opening, and the deflection prisms are arranged so that deflecting directions may become reverse. The slit opening is made equally to spread across the deflection prisms approximately and is impermeable except the slit opening, and light incident on the deflection prisms passes only this slit opening. In addition, the light which is emitted by a focus index illumination light source illuminates the slit opening through the deflection prisms. As to an image of the illuminated slit opening, two slit images are formed on a fundus of eye by actions of the deflection prisms. Focus adjustment is made by aligning these slit images in a straight line.

1 - 8 . (canceled) 
     
     
         9 . An ophthalmic image sensing apparatus comprising:
 a plurality of visible light sources located in conjugation positions with an anterior segment of an eye to be examined; and   a projection unit for projecting a fixation target at a different position on a fundus of the eye to be examined, in accordance with one selected among the plurality of visible light sources.   
     
     
         10 . The ophthalmic image sensing apparatus according to  claim 9 , further comprising a light source for emitting an infrared light to illuminate the fundus,
 wherein the projection unit transmits the infrared light.   
     
     
         11 . The ophthalmic image sensing apparatus according to  claim 10 , wherein the projection unit has as the fixation target, a plurality of openings slantly pierced in a direction different from an optical axis. 
     
     
         12 . The ophthalmic image sensing apparatus according to  claim 10 , wherein the projection unit has an opening which transmits a visible light, and prisms each of which is located in accordance with the opening and deflects the visible light in a direction different from others. 
     
     
         13 . The ophthalmic image sensing apparatus according to  claim 10 , wherein the plurality of visible light sources include a plurality of white LED light sources. 
     
     
         14 . The ophthalmic image sensing apparatus according to  claim 9 , further comprising a first relay lens and a second relay lens each of which has a focal position conjugating with an anterior segment of the eye to be examined,
 wherein the plurality of visible light sources are arranged circumferentially on a focal plane of the second relay lens, and   the projection unit is provided between the first relay lens and the second relay lens.   
     
     
         15 . The ophthalmic image sensing apparatus according to  claim 9 , further comprising a selection unit for selecting one visible light source among the plurality of visible light sources,
 wherein the projection unit projects the fixation target at the different position on the fundus by using the one visible light source selected by the selection unit.   
     
     
         16 . The ophthalmic image sensing apparatus according to  claim 15 , wherein the selection unit selects the one visible light source among the plurality of visible light sources in accordance with the right and left of the eye to be examined. 
     
     
         17 . The ophthalmic image sensing apparatus according to  claim 15 , further comprising a control unit for controlling the plurality of visible light sources so as to turn on the selected visible light source with luminance darker than that at a time of image sensing of the eye to be examined, to emit a stationary light. 
     
     
         18 . The ophthalmic image sensing apparatus according to  claim 15 , further comprising a control unit for controlling the plurality of visible light sources so as to turn on the selected visible light source at a time of image sensing of the eye to be examined, with luminance brighter than that at a time of projecting the fixation target. 
     
     
         19 . The ophthalmic image sensing apparatus according to  claim 18 , wherein the plurality of visible light sources and the projection unit are provided on an illumination optical system for illuminating the eye to be examined, and
 the control unit causes, at the time of image sensing of the eye to be examined, once the selected visible light source is turned off, the projection unit to remove from an optical path of the illumination optical system, and the selected visible light source to turn on with luminance brighter than that at the time of projecting the fixation target.   
     
     
         20 . The ophthalmic image sensing apparatus according to  claim 9 , wherein the plurality of visible light sources and the projection unit are provided on an illumination optical system for illuminating the eye to be examined,
 the ophthalmic image sensing apparatus further comprising a control unit for causing the projection unit to remove from an optical path of the illumination optical system at a time of image sensing of the eye to be examined.   
     
     
         21 . The ophthalmic image sensing apparatus according to  claim 9 , further comprising a right-left eye selection unit for selecting a right eye or a left eye as the eye to be examined,
 wherein the projection unit projects the fixation target at the different position on the fundus in accordance with a selection result of the right-left eye selection unit.