Position adjusting device for ophthalmologic instrument

A position adjusting device attached to an ophthalmologic measuring instrument to accurately position an eye to be examined with respect to the ophthalmologic measuring instrument, said device comprising:

• (a) first projection means for projecting a predetermined projection pattern upon the eye to be examined;
• (b) an objective lens group for forming therethrough the reflected image of said projection pattern by the cornea of said eye to be examined;
• (c) a field stop provided at the image forming position of said objective lens group;
• (d) a light-intercepting member provided near said objective lens group and having two openings outside of the optic axis of said objective lens group;
• (e) a reflecting member obliquely disposed on the optic axis of said objective lens group rearwardly of and near said light-intercepting member;
• (f) second projection means for projecting a standard chart image onto the position of said field stop through the reflection on said reflecting member so as to coincide the center of the standard chart image with the optical axis of said objective lens;
• and
• (g) an eyepiece for observing the image of said projection pattern and the image of said standard chart both formed at the position of said field stop;
• whereby the distance adjustment between said ophthalmologic measuring instrument and said eye to be examined is achieved by moving said measuring instrument relative to said eye so that dual images resulting from light rays passing through said two openings of said light-intercepting member respectively coincide with each other, and whereby the position adjustment of said ophthalmologic measuring instrument and said eye to be examined may be achieved by moving said measuring instrument relative to said eye so that the image of said projection pattern and the image of said standard chart are formed in a predetermined positional relation at the position of said field stop.