Patent ID: 7248371

Claim:
An optical image measuring apparatus for obtaining an image of an object to be measured at a depth corresponding to a position of a reference object based on interference light, comprising: a light source for emitting a light beam; an interference optical system that divides the light beam emitted from the light source into signal light propagating through the object to be measured and reference light propagating through the reference object, shifts a frequency of the signal light and a frequency of the reference light relative to each other, and then superimposes the signal light propagating through the object to be measured and the reference light propagating through the reference object on each other to produce the interference light; intensity modulating means for periodically modulating an intensity of the interference light from the interference optical system at a predetermined frequency; photo detection means for receiving the interference light whose intensity is modulated by the intensity modulating means to perform photoelectric conversion, storing a charge for only a predetermined storage time, and outputting an electrical signal corresponding to an amount of charge stored; control means for changing the storage time of the photo detection means; and calculation means for calculating a phase and an intensity of the interference light at a depth of the object to be measured, which is detected by the photo detection means based on the electrical signal outputted from the photo detection means every storage time changed by the control means.