Wavelength-tunable light generator and optical coherence tomography device

Abstract

The present invention provides an OCT technique that permits tomographic observation of a biological body parts that is difficult to restrain and also provides a tomographic observation technique for the observation of a constrainable part that does not require constraint and remove the burden from biological body. A wavelength-tunable light generator (wavelength-tunable light source) is employed as the light source of the optical coherence tomography device. The wavelength-tunable light generator has a wave number tunable range width of at least 4.7×10 −2 μm −1 and an emitted-light frequency width of no more than 13 GHz, for example, and includes means capable of changing the wave number stepwise at wave number intervals of no more than 3.1×10 −4 μm −1 and time intervals of no more than 530 μs.

1 . A wavelength-tunable light generator for dental optical coherence tomography, wherein the wavelength can be switched stepwise in the range 0.9 μm to 5.0 μm. 
     
     
         2 . The wavelength-tunable light generator for dental optical coherence tomography according to  claim 1 , wherein the width of the tunable range of said wave number is at least 4.7×10 −2  μm −1 , the frequency width of the emitted light is no more than 13 GHz, the wave number interval is no more than 3.1×10 −4  μm −1 , and said wave number can be switched stepwise at time intervals of no more than 530 μs. 
     
     
         3 . A dental optical coherence tomography device which uses the wavelength-tunable light generator according to  claim 1  in a light source as wavelength-tunable light generating means. 
     
     
         4 . The dental optical coherence tomography device according to  claim 3 , comprising:
 polarization characteristic measuring means for measuring the polarization characteristic of a tooth.   
     
     
         5 . The dental optical coherence tomography device according to  claim 4 , wherein said polarization characteristic measuring means comprise:
 main dividing means for dividing the light from said wavelength-tunable light generating means into measurement light and reference light with controlling the polarization direction of the light;   measurement light irradiating means for irradiating a tooth in an oral cavity with said measurement light divided by said main dividing means;   signal light collecting means for collecting signal light that is reflected by the tooth following irradiation of said tooth;   combining means for separating said signal light collected by said signal light collecting means into components of two or more polarization directions and for respectively combining the separated light components with said reference light divided by said main dividing means; and   computation control means for finding the polarization characteristic of said tooth on the basis of the intensity of the signal light of different polarization directions thus combined.   
     
     
         6 . The dental optical coherence tomography device according to  claim 3 , wherein said polarization characteristic measuring means comprise:
 main dividing means for dividing the light from said wavelength-tunable light generating means into measurement light and reference light;   measurement light irradiating means for irradiating a tooth in an oral cavity with said measurement light divided by said main dividing means;   signal light collecting means for collecting said signal light that is reflected by the tooth following the irradiation of said tooth;   combining means for combining the signal light collected by said signal light collecting means and said reference light divided by said main dividing means; and   computation control means for controlling said wavelength-tunable light generating means so that said light from said wavelength-tunable light generating means has the intended wavelength range and for finding the characteristics of said tooth on the basis of the wavelength range of the light from said wavelength-tunable light generating means and the intensity of the light combined by said combining means,   wherein said computation control means control said wavelength-tunable light generating means so that light of a plurality of different wavelength ranges is output and find the characteristics of said tooth by finding the intensity of said light combined by said combining means for each wavelength range.