Optical: systems and elements – Single channel simultaneously to or from plural channels
Reexamination Certificate
2002-07-29
2004-10-26
Mack, Ricky (Department: 2873)
Optical: systems and elements
Single channel simultaneously to or from plural channels
C359S212100, C359S223100, C359S626000, C359S627000
Reexamination Certificate
active
06809866
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical imaging apparatus for obtaining optical image information of a subject portion by scanning with beams from a light source.
2. Description of the Related Art
Recently, an optical imaging apparatus called an OCT (Optical Coherence Tomography) has widely been used. The optical imaging apparatus forms a tomogram of the inside of a subject portion based on information on light which returns from the subject portion by irradiating the subject portion with light having low coherence caused in a light source and then scanning a focus position.
As disclosed in U.S. Pat. No. 6,151,127, Optics Express Vol. 6, No. 7, 136-145 (Optical Society of America, on March, 2000), and Japanese Unexamined Patent Application Publication No. 11-72431 which was applied by the present applicant, the above-mentioned optical imaging apparatus can obtain a three-dimensional tomogram of a subject portion by two-dimensionally scanning the subject portion with an objective optical system for condensing light with low coherence to the subject portion and by scanning it in an optical axis direction.
An optical system of the above-mentioned conventional optical imaging apparatus separates the light with the low coherence generated by the light source into irradiation light and reference light by light separating means, scans (two-dimensionally scans) the subject portion with the separated irradiation light, and condenses the light to the subject portion at a focus point of the objective optical system. Then, reflection light and scattering light of the subject portion from the focus point pass through the same optical path as that of the irradiation light, and return to the light separating means again. In this case, the subject portion in the depth direction is scanned by the scanning operation in the optical direction with the objective optical system.
On the other hand, the reference light separated by the light separating means is reflected by reference light reflecting means, and is returned to the light separating means again. Then, the reference light reflecting means advances and regresses in the optical axis direction so that the length of the optical path of the reflected reference light is almost equal to the lengths of the optical paths of the reflection light and the scattering light from the subject portion.
The reflected reference light and the reflection light and scattering light from the subject portion, having almost the same length of the optical paths interfere each other, and an optical detector as optical detecting means detects these light. An output of the optical detector is demodulated by a demodulator and an interfered optical signal is extracted. The extracted optical signal is converted into a digital signal, is thereafter subjected to signal processing, and image data corresponding to the tomogram is generated. The generated image data is displayed on a monitor as a three-dimensional tomogram of the subject portion.
However, the above-mentioned conventional optical imaging apparatus independently comprises means for advancing and regressing the above-described objective optical system in the optical axis direction and means for advancing and regressing the reference-light reflecting means in the optical axis so that the length of the optical path of instrumentation light matches that of the reference light. Consequently, the above-mentioned conventional optical imaging apparatus has two drive systems.
Thus, the above-mentioned conventional optical imaging apparatus has a larger optical system. When it is incorporated in an endoscope insertion portion or an optical scanning probe which is used by being inserted into the body cavity, there is such a problem that the diameter of these insertion portions becomes large.
Further, the above-mentioned conventional optical imaging apparatus has two control systems for individually controlling the above drive systems. The two drive systems must be controlled synchronously with the two control systems. Therefore, the above-mentioned optical imaging apparatus has complex structures of the control systems and, thus, costs are increased.
The optical imaging apparatus has, for example, an optical probe for scanning the anatomy of the subject portion with laser beams (coherent beams) from the light source and for condensing the light at the focus point of the objective optical system. The optical probe has a conjugate focus-point optical system for obtaining the tomogram of the anatomy by receiving return light, as the reflection light and the scattering light from the anatomy of the subject portion obtained via the objective optical system, by receiving light means having a conjugate focus point of the objective optical system.
As disclosed in, for example, U.S. Pat. No. 5,788,639, the above optical imaging apparatus is proposed, in which the entire optical system is arranged onto a single base and this base is moved in the horizontal direction, thus adjusting a range of a field of view for observation in the horizontal direction. Therefore, in the optical imaging apparatus disclosed in the U.S. Pat. No. 5,788,639, the range of the field of view for observation as a fine observation range is moved in the horizontal direction of the subject portion and the field of view of the objective optical system can be arranged.
On the other hand, as disclosed in, for example, U.S. Pat. No. 5,120,953, an optical imaging apparatus is proposed, in which a surface of the anatomy of a subject portion is absorbed, thereby adjusting the range of the field of view for observation in the vertical direction (depth direction) of the subject portion. Thus, in the optical imaging apparatus disclosed in U.S. Pat. No. 5,120,953, the range of the field of view for observation as a fine observation range can be adjusted in the vertical direction.
As disclosed in Japanese Unexamined Patent Application Publication No. 6-154228 which was applied by the present applicant, an optical imaging apparatus is proposed, in which a TV camera for image pick-up of a surface observation image within the range of the field of view for observation is provided. Consequently, the optical imaging apparatus disclosed in Japanese Unexamined Patent Application Publication No. 6-154228 can simultaneously display both the surface observation image and the tomogram of the subject portion.
Upon moving and adjusting the base on which the entire optical system is arranged, the optical imaging apparatus disclosed in U.S. Pat. No. 5,788,639 requires the adjustment of the optical axis with high accuracy. Thus, in the optical imaging apparatus disclosed in the U.S. Pat. No. 5,788,639, the adjustment of the optical axis is complicated and is difficult.
In the optical imaging apparatus disclosed in U.S. Pat. No. 5,788,639, the base on which the entire optical system is arranged is moved and adjusted. Therefore, the arrangement of the moving and adjusting means in the optical probe causes such a problem that the whole optical probe is increased.
Meanwhile, in the optical imaging apparatus disclosed in U.S. Pat. No. 5,120,953, the range of the field of view for observation can be adjusted in the vertical direction (depth direction) of the subject portion. However, there is such a problem that the range of the field of view for observation cannot be adjusted in the horizontal direction of the subject portion.
Further, in the optical imaging apparatus disclosed in Japanese Unexamined Patent Application Publication No. 6-154228, both the surface observation image and the tomogram of the subject portion can simultaneously be displayed. However, there is such a problem that the range of the field of view for observation cannot be adjusted in the horizontal direction and the vertical direction (depth direction) of the subject portion.
Recently, endoscopes have widely been used in medical fields and industrial fields. As disclosed in Japanese Unexamined Patent Application Publication No. 6-154228, in addition to a normal
Kamihara Yasuhiro
Kaneko Mamoru
Okamura Toshiro
Xie Tianyu
Mack Ricky
Olympus Corporation
Scully Scott Murphy & Presser
Thomas Brandi N
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