Patent ID: 6813030
Filing Date: 2004-11-02
Classification: A61B,G01B,G01N,G02B

Abstract:
An optical interference tomographic image observing apparatus, characterized by comprising a rotary prism apparatus which includes a Littrow reflector prism having a 90-degree vertex and disposed near a circumference of a rotary body in such a manner that a surface facing the vertex extends substantially perpendicular to a tangential line of the circumference, the prism having a characteristics such that when a light beam impinges the surface, the light beam is reflected in a direction parallel to the incidence direction, wherein through utilization of the characteristics, the reflection point can be scanned in a predetermined direction as the rotary body rotates; and a delay reflection light beam is periodically generated when the rotary body rotates in the travel direction of the light beam and a progressive reflection light beam is periodically generated when the rotary body rotates in the opposite direction, wherein the optical interference tomographic image observing apparatus further comprises: means for splitting a light beam from a low-coherence light source into two light beams, one of the light beams, serving as reference light, being delayed or advanced by means of rotary scanning of the reflection point in order to obtain a reflection light beam having a Doppler shift frequency, and the other light beam being converged to an object to be measured which has a multilayer structure in terms of refraction index distribution; an objective lens for capturing object reflection light from a scattering potential portion at a deep portion of the multilayer object; a photo detector for performing heterodyne detection for obtaining a beat signal of the shift frequency, which is generated on the basis of the low coherence, characterized in that a maximum interference signal can be obtained only when the reference light and the object reflection light merge together after passage through respective optical paths having the same optical path length as measured from the split point; means for calculating, in the form of coordinates, the scanned reflection point of the delay or progressive reflection light beam; and a signal control processing system, a computer, and a display which measure and display a reflection tomographic image, while using, as image data, the coordinates and an amplitude of the beat signal representing reflection light from the scattering potential at the deep portion of the object to be measured.