Optical tomographic imaging apparatus

Abstract

Provided is an optical tomographic imaging apparatus which enables simplification and cost reduction without reducing accuracy when moving part of an object is moved in an optical axis direction of measuring beam. The apparatus using return beam of measuring beam reflected or scattered by an object and reference beam reflected by a reference mirror to image the tomographic image, includes: a reflecting position controlling device for controlling the reflecting position of the reference mirror; a detecting device for a position in a moving part having an optical system for observing the moving part illuminated by an optical system imaging the same on an area sensor based on the Scheimpflug principle and detects position information that the moving part is moved in the direction; and a device for driving the reflecting position controlling device to control the optical path length of the reference beam based on the position information.

1 . An optical tomographic imaging apparatus which splits light from a light source into measuring beam and reference beam, guides the measuring beam to an object, guides the reference beam to a reference mirror, and uses return beam of the measuring beam reflected or scattered by the object and the reference beam reflected by the reference mirror to image the tomographic image of the object, comprising:
 a reflecting position controlling device for controlling the reflecting position of the reference mirror;   a detecting device for detecting a position in a moving part which has an optical system for observing moving part of the object illuminated by an optical system for illumination with the light from the light source by imaging the same on an area sensor based on the Scheimpflug principle and detects position information that the moving part of the object is moving in an optical axis direction of the measuring beam; and   a device for driving the reflecting position controlling device to control the optical path length of the reference beam according to the position information detected by the detecting device for detecting a position in a moving part and reducing the deformation of the tomographic image of the object due to position displacement of the moving part of the object.   
     
     
         2 . The optical tomographic imaging apparatus according to  claim 1 , wherein the object is an eye, the moving part of the object is an anterior ocular segment, and the detecting device for detecting a position in a moving part can detect the positions back and forward the movement of the cornea of the eye in an optical axis direction of the measuring beam. 
     
     
         3 . The optical tomographic imaging apparatus according to  claim 1 , wherein when the depth resolution of the optical tomographic imaging apparatus is Δ, the optical magnification of the optical system for observing moving part is β, and the pitch of the area sensor is p, the following equation is satisfied:
   Δ×≈> p  
 
 
     
     
         4 . The optical tomographic imaging apparatus according to  claim 1 , wherein the optical system configured in the optical path of the measuring beam and the optical system for illuminating the moving part of the object in the optical tomographic imaging apparatus are partially shared. 
     
     
         5 . The optical tomographic imaging apparatus according to  claim 2 , wherein the detecting device for detecting a position in a moving part can derive the radius of curvature R of the cornea by illuminating the center position of the eye with a slit beam, and can calculate the coordinates of the apex of the cornea from the difference between the radius of curvature R and the radius of curvature R′ of the cornea derived in the tomographic image of the anterior ocular segment. 
     
     
         6 . The optical tomographic imaging apparatus according to  claim 2 , wherein the detecting device for detecting a position in a moving part can derive the radius of curvature R of the cornea by illuminating the center position of the eye with crossed light of two slit beams and calculate the coordinates of the apex of the cornea from the difference between the radius of curvature R and the radius of curvature R′ of the cornea derived in the tomographic image of the anterior ocular segment.