JP4142402B2 - Confocal endoscope - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a confocal endoscope having a confocal microscope function for extracting only reflected light on a focal plane of an objective optical system by a pinhole, and a confocal endoscope apparatus including the confocal endoscope. .
[0002]
[Prior art]
2. Description of the Related Art Conventionally, endoscopes are configured so that when an operator inserts an endoscope into a body cavity, the inside of the body cavity can be observed with a wide field of view in order to easily grasp the observation position. However, in the case of an endoscope configured to observe the inside of a body cavity with such a field of view, the observation magnification is low even if the observation position of the endoscope in the body cavity can be grasped, so observe the details of the observation target. Has become difficult. As a result, in order to deal with this detail, an operator's skill in endoscope operation is required. Therefore, in order to solve this problem, an endoscope having a zoom function has been proposed and widely used (for example, see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-98945 (term 3, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, the endoscope having the zoom function described above is an electronic zoom that electrically enlarges and displays an image. Therefore, when the zoom magnification is increased, the image itself deteriorates, and a clear observation image can be obtained. Can not. As a result, the operator has to deal with the details of the observation target while observing the unclear image, and thus a skilled endoscope operation capability is required.
[0005]
Further, there is an optical zoom endoscope provided with an optical system having a variable focal length. However, since the zoom optical system needs to be disposed at the distal end of the endoscope, the scope diameter becomes large. Further, it is impossible to simultaneously observe both the high-magnification observation image and the low-magnification observation image.
[0006]
In addition, when examining a living tissue in a conventional precision diagnostic examination, in order to examine the inside of the living tissue, a part of the living tissue to be examined is cut out using a treatment tool such as a forceps, and is removed from the body. I put out and inspected. For this reason, the diagnosis time becomes long and the subject cannot be treated quickly.
[0007]
Therefore, in view of the above circumstances, the present invention can obtain a good high-magnification observation image so that an operator can easily perform a treatment on a living tissue, and can shorten a diagnosis time. It is an object of the present invention to provide an endoscope capable of promptly treating a person, and an endoscope apparatus including the endoscope.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, a confocal endoscope according to one aspect of the present invention includes a surface observation unit that observes a surface of a biological tissue in a body cavity at a first magnification, and a surface or a tomogram of the biological tissue. In order to observe at a second magnification higher than 1, the surface or slice of the living tissue is scanned by a scanning mirror, and only the reflected light at the focal plane of the objective optical system is extracted by a pinhole from the obtained reflected light A confocal extraction unit, and a deflection unit that is disposed downstream of the objective optical system and transmits or deflects a light beam incident from the objective optical system according to a polarization state. So that the non-polarized light beam incident from the objective optical system is transmitted and guided to the surface observation unit, and the linearly polarized light beam incident on the objective optical system is Deflection to extract the confocal Having a deflection unit to guide the. That is, the confocal endoscope includes two observation means, that is, a surface observation unit and a confocal extraction unit, and the optical path of the confocal extraction unit is deflected by the deflection unit. It is possible to observe the same observation object simultaneously with the observation means. Further, since the confocal extraction unit can observe the tomographic image of the living tissue at a high magnification, the operator can inspect the living tissue in the body cavity. Therefore, the diagnosis time can be shortened and the subject can be treated quickly.
[0009]
In the confocal endoscope, the surface observation unit and the confocal extraction unit may be configured to observe a living tissue by a common objective optical system. That is, when the confocal endoscope is configured so that the two observation means are observed with the same objective optical system, the parallax is eliminated and a good observation image can be obtained.
[0010]
In the above confocal endoscope, the deflection unit may be a polarization beam splitter. In this case, it is possible to easily configure the confocal endoscope so that the two observation units are observed with the same objective optical system.
[0011]
In the confocal endoscope, the pinhole is an end surface of a single mode optical fiber disposed at a position conjugate with the object side focal position of the objective optical system. That is, by disposing the end face of a single-mode optical fiber having a small core diameter at a position conjugate with the object side focal position of the objective optical system, this optical fiber has the function of a pinhole used in the confocal optical system, And a function of transmitting an observation image obtained by the confocal optical system to an external device such as an image generation unit.
[0012]
Further, a confocal endoscope device including the confocal endoscope according to any one of the above, an illumination unit that illuminates the surface of the biological tissue, a light source that irradiates the surface of the biological tissue or a tomogram, And an image generation unit that generates an observation image based on a signal obtained by the endoscope.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing a configuration of a confocal endoscope apparatus 500 according to an embodiment of the present invention. The confocal endoscope apparatus 500 includes a confocal endoscope 100, a processor 300, and a monitor 400.
[0014]
The confocal endoscope 100 has a surface observation unit that observes the inside of a body cavity with a wide field of view by reflected light obtained when the inside of the body cavity is illuminated with illumination light. The surface observation unit includes an objective lens 110, a CCD 120, a light guide 130, and an illumination lens 131.
[0015]
In this embodiment, the color image obtained by the CCD 120 is obtained by a frame sequential method. An RGB rotation filter 331 is provided in the illumination light path of the light source 330 included in the processor 300. The RGB rotation filter 331 includes three color filters of R, G, and B. As the RGB rotation filter 331 rotates, the illumination light of the light source 330 passes through the filters of each color, is guided to the observed site 200 by the light guide 130 via the condenser lens 332, and the observed site 200 is transmitted through each color. Illuminate with illumination light.
[0016]
The reflected light of the observation site 200 illuminated with the illumination light of each color is sequentially imaged by the CCD 120 via the objective lens 110 and the deflecting unit 150 described later. The image signals of each color are processed by the processor 300, and a color image is obtained by making the processed image signals of each color into one image.
[0017]
The image signal of the observed region 200 obtained by the CCD 120 is transmitted to a preprocess processing circuit 310 inside the processor 300. The preprocess processing circuit 310 amplifies the image signal and performs sampling and holding processing. The image signal is output to the A / D converter 311.
[0018]
The A / D converter 311 converts this image signal into a digital signal and outputs it to the endoscope image signal processing circuit 312. This digital signal is switched by the endoscope image signal processing circuit 312 in synchronization with the driving of the RGB rotation filter 331, separated into R, G, and B color image signals and output to the RGB memory 313.
[0019]
The RGB memory 313 includes three frame memories corresponding to each color, and each separated color image signal is stored in the corresponding frame memory. The stored color image signals are simultaneously read out, converted into analog signals by the D / A converter 314, and output to the endoscope video output signal circuit 315.
[0020]
The endoscope video output signal circuit 315 converts the analog signal into an RGB video signal output, a composite video signal, or an S video signal for display on the monitor 400 and outputs the signal. When these video signals are output to the monitor 400, an observation image with a wide field of view is displayed on the monitor. In the present embodiment, the color image is obtained by the frame sequential method. However, for example, a color simultaneous electronic endoscope that includes an RGB mosaic filter on the front surface of the CCD and images with a white light source may be used.
[0021]
The confocal endoscope 100 includes a GRIN lens 140, an optical fiber 141, a polarization unit 150, and micromirrors 153 and 156. These optical elements are confocal extraction units for observing a surface image or a tomographic image in a body cavity at a high magnification.
[0022]
The processor 300 has a laser light source 301. The laser light source 301 oscillates a He—Ne laser having an oscillation wavelength of 632 nm. The laser light source used for the confocal extraction unit can obtain higher resolution as the wavelength is shorter. That is, the laser light source 301 is not limited to a He—Ne laser, and may be, for example, a short wavelength Ar ⁺ laser. The laser light source 301 has a Brewster window, and a polarization separation film (not shown) is disposed in the vicinity thereof. The Brewster window and the polarization separation film are arranged so that the light beam emitted from the laser light source 301 becomes an s-polarized light beam with respect to the polarization separation film. The light beam emitted from the laser light source 301 is transmitted through the coupler 302 through the optical fiber 141 that is a single mode fiber.
[0023]
The GRIN lens 140 is a lens made of an optical material having a refractive index having a gradient inside the medium. The light beam emitted from the optical fiber 141 enters the GRIN lens 140, becomes a parallel light beam, and is emitted toward the polarizing film 151 included in the polarizing unit 150.
[0024]
The polarizing unit 150 includes two polarizing beam splitter cubes bonded together, and a λ / 4 wavelength plate 152 and a λ / 4 wavelength plate 155 are provided on each surface of the cube located in a direction parallel to the optical axis direction. Each is pasted. The two polarizing beam splitter cubes have a polarizing film 151 and a polarizing film 154, respectively. Each of these polarizing films has a characteristic of reflecting p-polarized light by reflecting an s-polarized light beam out of linearly polarized light. The λ / 4 wave plates 152 and 156 convert linearly polarized light beams into circularly polarized light beams, and convert circularly polarized light beams into linearly polarized light beams.
[0025]
The s-polarized parallel light beam emitted from the GRIN lens 140 is bent 90 degrees by the polarizing film 151 and guided to the λ / 4 wavelength plate 152. The parallel light beam passes through the λ / 4 wavelength plate 152, is converted into a circularly polarized parallel light beam by the λ / 4 wavelength plate 152, and is guided to the micromirror 153.
[0026]
FIG. 2 is a diagram illustrating the configuration of the micromirrors 153 and 156. The micromirrors 153 and 156 include a plate 161, a torsion bar 162, and an instruction frame 163 that are integrally formed from a silicon plate by etching. The plate 161 has a mirror 164 formed by vapor-depositing aluminum at the center thereof. Furthermore, a planar coil 165 made of a copper thin film is provided on the plate 161, the torsion bar 162, and the instruction frame 163. A yoke portion 166 composed of a permanent magnet and a yoke is disposed in parallel to the longitudinal direction of the torsion bar 162.
[0027]
The yoke portion 166 generates a magnetic field in a direction (X ′ direction in FIG. 2) that is substantially parallel to the plate 161 and substantially perpendicular to the longitudinal direction of the torsion bar 162. When a driving current is supplied from a power source (not shown) to the planar coil 165, driving forces, that is, torques differing in the Z ′ direction are generated on the two sides of the plate 161 parallel to the torsion bar 162 in accordance with Fleming's left hand rule. To do. Note that the torque generated at this time increases in proportion to an increase in the drive current supplied to the planar coil 165.
[0028]
In response to the generated torque, the plate 161 swings in the direction of arrow A in the figure. At this time, since the plate 161 and the torsion bar 162 are integrally formed, the torsion bar 162 is twisted to generate a spring reaction force. As a result, the plate 161 rotates to an angle at which the torque and the spring reaction force are balanced. When the plate 161 reaches an angle at which the forces are balanced, the plate 161 stops at that angle.
[0029]
The micromirror 153 and the micromirror 156 are arranged so that their torsion bars are orthogonal to each other. When the plate of the micromirror 153 is rotated, the laser beam is scanned in the X direction with respect to the observation site 200, and when the plate of the micromirror 156 is rotated, the laser beam is scanned in the Y direction with respect to the observation site 200. Is done. Note that the X and Y directions here are directions orthogonal to the optical axis and indicate the plane direction with respect to the observed region 200.
[0030]
The micromirrors 153 and 156 have two detection coils (not shown) on the opposite side of the surface of the plate 161 on which the planar coil 165 is provided. A detection current for detecting the displacement angle of the plate 161 is superimposed on the drive current that flows through the planar coil 165. Based on this detection current, an induced voltage due to mutual inductance between the planar coil 165 and each detection coil is generated in each detection coil.
[0031]
The two detection coils are arranged equidistant from the planar coil 165, respectively. That is, when the plate 161 is in a horizontal state (a state where no torque is generated), the induced voltage difference is zero. However, when the plate 161 swings, one detection coil approaches the planar coil 165 and the other detection coil is separated from the planar coil 165, so that a difference occurs in the induced voltages generated in the mutual detection coils. In other words, the displacement angle of the micromirror can be detected by detecting the change in the induced voltage.
[0032]
The circularly polarized parallel light beam guided to the micromirror 153 is reflected by the mirror of the micromirror 153, passes through the λ / 4 wavelength plate 152 again, and becomes a p-polarized parallel light beam with respect to the polarizing films 151 and 154. Since the polarizing films 151 and 154 have the property of transmitting p-polarized light as described above, the parallel light beams of p-polarized light are transmitted through the polarizing films 151 and 154 and guided to the λ / 4 wavelength plate 155.
[0033]
The p-polarized parallel light beam guided to the λ / 4 wavelength plate 155 passes through the λ / 4 wavelength plate 155, is converted into a circularly polarized parallel light beam by the λ / 4 wavelength plate 155, and is guided to the micromirror 153. . Then, the circularly polarized parallel light beam is reflected by the mirror of the micromirror 156, passes through the λ / 4 wavelength plate 155 again, and becomes an s-polarized parallel light beam with respect to the polarizing film 154.
[0034]
The s-polarized parallel light beam is bent 90 degrees by the polarizing film 154. The optical axis of the folded parallel light beam is the same optical axis as the optical axis of the surface observation unit described above. This parallel light beam is focused on the surface portion or tomographic portion of the observed site 200 via the objective lens 110. That is, since the surface observation unit and the confocal extraction unit observe the observation site 200 using the same objective lens, no parallax occurs between these observation units.
[0035]
The laser light emitted to the observed region 200 is reflected by the observed region 200 and enters the objective lens 110. Then, it becomes a parallel light beam by the objective lens 110 and enters the GRIN lens 140 through the same optical path as described above.
[0036]
Since the optical fiber 141 is a single mode fiber as described above, its core diameter is about 3 to 9 μm (depending on the wavelength used) and is very small. The end face 141a of the optical fiber 141 is disposed at a position conjugate with the object side focal position of the objective lens 110. That is, of the light beam incident on the GRIN lens 140, the reflected light of the light beam focused on the observation site 200 is focused on the end surface 141a. The light beam focused on the end face 141 a enters the optical fiber 141 and is received by the light receiving element 303 via the coupler 302.
[0037]
However, the reflected light of the observed region 200 other than the reflected light from the object-side focal plane of the objective lens 110 is not focused on the end surface 141 a and does not enter the optical fiber 141, and thus is not transmitted to the processor 300. That is, the optical fiber 141 transmits only the reflected light of the observed region 200 on the focal plane of the objective lens 110 to the processor 300. That is, in the present embodiment, the end surface 141a of the optical fiber 141 is a processor that uses a pinhole function for blocking light other than the reflected light from the object-side focal plane of the objective lens 110 and the observation image obtained by the confocal extraction unit. It also has the function of transmitting to 300.
[0038]
Further, since a pinhole, that is, an aperture stop is provided on the focal plane of the GRIN lens 140, the confocal extraction unit is a telecentric optical system, and the loss of light amount is extremely small.
[0039]
The light beam received by the light receiving element 303 is photoelectrically converted and output to the preprocess processing circuit 320. The preprocess processing circuit 320 amplifies the image signal and performs sampling and holding processing. The image signal is output to the A / D converter 321. The A / D converter 321 converts this image signal into a digital signal and outputs it to the confocal image signal processing circuit 322. The digital signal is switched by the confocal image signal processing circuit 322 in synchronization with the driving of the RGB rotation filter 331, separated into R, G, and B color image signals and output to the RGB memory 323.
[0040]
The memory 323 stores this digital signal. The stored signal is read at a predetermined timing, converted into an analog signal by the D / A converter 324, and output to the confocal video output signal circuit 325. The confocal video output signal circuit 325 converts this analog signal into various video signals for display on the monitor 400. When these video signals are output to the monitor 400, the observation image of the observed region 200 on the focal plane of the objective lens 110 generated by the confocal extraction unit is displayed on the monitor at a high magnification.
[0041]
The operator can observe a desired image obtained by the confocal optical system by operating an operation panel 340 provided in the processor 300. Information input to the operation panel 340 by the operator is transmitted to the CPU 350. The CPU 350 controls the timing generator 351 based on the transmitted information.
[0042]
The timing generator 351 drives the micromirror 153 and the micromirror 156 included in the confocal endoscope 100 under the control of the CPU 350. When the micromirror 153 or the micromirror 156 is driven, the laser beam scans in the X direction or the Y direction (that is, the plane direction) with respect to the observation site 200 as described above. Then, the reflected light of the scanned part is transmitted to the processor 300 as an observation image.
[0043]
Furthermore, the magnification of the observed image can be easily changed by changing the scanning angle of the micromirror (that is, the range of the laser beam scanned at the observation site 200). When the scanning angle is small, the observation image has a high magnification. When the scanning angle is large, the observation image has a low magnification. In other words, it is possible to change the magnification of the observation image only by changing the scanning angle of the micromirror without having a zoom optical system composed of a plurality of groups and a plurality of lenses, and thus the size of the apparatus can be reduced. It becomes.
[0044]
Further, the operator can select a display method of the observation image displayed on the monitor 400 by operating the operation panel 340. For example, the observation image by the surface observation unit and the observation image by the confocal extraction unit are selectively switched and displayed over the entire display area of the observation image of the monitor 400, or the display area is divided into two and the observation image by both optical systems. Can be displayed simultaneously. Moreover, since the observation image by the observation image by the surface observation part has a wide viewing angle, it can be used as a finder of the confocal extraction part.
[0045]
The above is the embodiment of the present invention. The present invention is not limited to these embodiments and can be modified in various ranges.
[0046]
In this embodiment, the observation image of the observed region 200 obtained by the confocal extraction unit is a two-dimensional image obtained using a micromirror that scans laser light in the XY directions. You may comprise so that a three-dimensional image may be acquired by adding the micromirror which scans to the depth direction of 200. FIG.
[0047]
Further, in the present embodiment, there is one monitor that displays an observation image, but a plurality of monitors are connected to the processor 300, and the observation image by the optical system of the endoscope and the observation image by the confocal extraction unit are separately provided. You may comprise so that it may display on a monitor.
[0048]
In the present embodiment, the observation image having a wide viewing angle is an electronic image captured by a CCD. However, the operator may directly observe the image using a fiber.
[0049]
In this embodiment, the He—Ne laser is used as the light source for irradiating the site 200 to be observed. However, an ultrahigh pressure mercury lamp that irradiates light having a short wavelength including near ultraviolet rays may be used as the light source. . In this case, the fluorescence emitted from the observed site 200 can be observed.
[0050]
【The invention's effect】
As described above, the confocal endoscope and the confocal endoscope apparatus of the present invention include a surface observation unit that observes the surface of a biological tissue with a wide field of view, and a common observation that observes the surface or a tomogram of the biological tissue at high magnification. Since the optical path of the confocal extraction unit is deflected by the deflecting unit, the same observation object can be simultaneously observed by the observation units having different magnifications. Therefore, the operator can easily treat the details of the living tissue with the high-magnification observation image while grasping the observation position with the low-magnification observation image. In addition, since the confocal optical system can observe a tomographic image of a living tissue at a high magnification, it is not necessary to cut out a part of the living tissue and take it out of the body for inspection. As a result, the diagnosis time can be shortened and the subject can be treated quickly.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a confocal endoscope apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a micromirror used in an embodiment of the present invention.
[Explanation of symbols]
100 confocal endoscope 300 processor 500 confocal endoscope apparatus

Claims (5)

A surface observation unit for observing the surface of the biological tissue in the body cavity at a first magnification;
To observe the surface or fault of the living tissue in the above first magnification second magnification, to scan the surface or fault of the biological tissue by the scanning mirror, the reflected light obtained, the focus of the objective optical system A confocal extraction unit that extracts only reflected light on the surface by a pinhole;
A deflection unit that is arranged at a subsequent stage of the objective optical system and transmits or deflects a light beam incident from the objective optical system according to a polarization state, and a part of an observation region by the surface observation unit is the confocal point The unpolarized light beam incident from the objective optical system is transmitted through the objective optical system so as to be magnified and observed by the extraction unit and guided to the surface observation unit, and the linearly polarized light beam incident on the objective optical system is deflected to A deflection unit leading to the confocal extraction unit ;
Having a confocal endoscope.   The confocal endoscope according to claim 1, wherein the surface observation unit and the confocal extraction unit observe a living tissue by the common objective optical system. The deflection unit, a confocal endoscope according to claim 1 or claim 2, characterized in that a polarizing beam splitter.   The said pinhole is an end surface of the single mode optical fiber arrange | positioned in the position conjugate with the object side focal position of the said objective optical system, The Claim 1 characterized by the above-mentioned. Confocal endoscope. The confocal endoscope according to any one of claims 1 to 4,
Illumination means for illuminating the surface of the biological tissue;
A light source that illuminates the surface or tomography of a biological tissue;
An image generation unit that generates an observation image based on a signal obtained by the confocal endoscope;
A confocal endoscope device characterized by comprising:

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