JP4278086B2 - Scanning confocal probe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a scanning confocal probe capable of observing a tomographic image of a living tissue in a body cavity at a high magnification, and more particularly to a side-viewing scanning confocal probe that observes living tissue from the side of the probe.
[0002]
[Prior art]
Conventionally, when a biological tissue is inspected by a precision diagnostic inspection, a part of the biological tissue to be inspected is collected using a treatment tool such as a cutting forceps and then inspected outside the body. As a result, the diagnosis time becomes longer and the subject cannot be treated promptly.
[0003]
In recent years, confocal probe devices that can observe a tomographic image of a living tissue have become widespread. The confocal probe device includes a micro-machined small confocal probe used in a confocal microscope at the tip. The confocal probe device obtains a two-dimensional or three-dimensional observation image by scanning a laser beam on an observation target with a scanning mirror provided inside the probe. As such an apparatus, it is disclosed by the following patent document 1 or patent document 2, for example.
[0004]
[Patent Document 1]
Japanese Patent No. 3032720 (Items 3-5, FIGS. 1-5)
[Patent Document 2]
Japanese Patent No. 3052150 (3rd, 4th term, Fig. 1)
[0005]
The conventional confocal probe device has a probe. The inside of the probe has a cavity formed by cutting into a predetermined shape. A semiconductor material such as a silicon substrate, a scanning mirror, or the like is attached to the cavity. Specifically, the scanning mirror is mounted on a silicon substrate. And this board | substrate is attached to the probe inner wall by the board | substrate attachment part etc. Therefore, the number of processes in the probe assembling work increases and each process becomes complicated. In particular, the scanning mirror is required to be positioned with high accuracy because of the relationship with the optical system in the other probe, but it is extremely difficult to mount the scanning mirror while positioning it in the cavity with high accuracy. Further, the substrate mounting portion is provided on the outer side (probe inner wall side) with respect to the optical axis from the scanning mirror. Therefore, there are also disadvantages that the entire probe is enlarged and the diameter is increased.
[0006]
[Problems to be solved by the invention]
Therefore, in view of the above circumstances, the present invention provides a side-view type scanning confocal probe that can simplify the assembly process including the positioning operation of the scanning mirror and is miniaturized and reduced in diameter. For the purpose.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, a scanning confocal probe according to the present invention relates to a side-viewing scanning confocal probe that irradiates a light beam from a light source in a direction substantially orthogonal to a direction of insertion into a body cavity. A pentaprism which is disposed on the optical path and bends the optical path twice by the first surface and the second surface, and a scanning unit which is attached on the pentaprism and scans the light beam on the living tissue in the body cavity. It is characterized by that.
[0008]
By disposing a pentaprism for guiding the light beam for side view in the light path of the light beam from the light source, the space used as the light path and the space where the scanning means are disposed can be combined. Therefore, the housing which is the outer shape of the probe can be reduced, and the probe can be reduced in size and diameter.
[0009]
In addition, the scanning confocal probe further includes a condensing unit that condenses the light beam emitted from the pentaprism on a living tissue in the body cavity (claim 2). As the condensing means, besides the objective lens, a diffractive surface can be provided on the light exit end face of the pentaprism.
[0010]
According to the scanning confocal probe of claim 4, it is desirable that the scanning unit has a biaxial scanning mirror that scans the light beam in the first direction and the second direction orthogonal to the first direction. . The biaxial scanning mirror is mounted on either the first surface or the second surface of the pentaprism. By mounting a biaxial scanning mirror as a scanning unit on either surface of the pentaprism, relative positioning between the biaxial scanning mirror and the pentaprism can be easily performed with high accuracy. Thereby, simplification of a manufacturing and an assembly process can be aimed at.
[0011]
It should be noted that a loss of light quantity can be suppressed if a metal single layer film or the like is applied to the surface of the pentaprism where the biaxial scanning mirror is not mounted to form a mirror surface. Further, it is desirable that the scanning means such as a biaxial scanning mirror is disposed at a position that is focused when a parallel light beam is incident on the light collecting means from the living tissue side. As a result, the scanning means and the light collecting means have a telecentric relationship, and the light beam is incident at right angles on the living tissue that is the site to be observed. Therefore, it is possible to observe a brighter and finer image while suppressing the light loss.
[0012]
According to the invention described in claim 8, the scanning means includes a first scanning mirror that scans the light beam in the first direction, and a second scan that scans the light beam in the second direction orthogonal to the first direction. A configuration having a scanning mirror can also be adopted. In this case, the first scanning mirror and the second scanning mirror may be mounted on the first surface and the second surface of the pentaprism, respectively.
[0013]
According to the ninth aspect of the present invention, it is desirable that the light collecting means and the pentaprism are made of the same material. Thereby, the difference in the expansion coefficient of each optical element disposed in the probe is reduced. As a result, even when the temperature change received by the probe is large, it is possible to suppress the amount of deviation of the positional relationship between the optical elements due to the difference in expansion coefficient, and the temperature characteristics are improved.
[0014]
The scanning confocal probe according to claim 10 is disposed so as to remove reflected light other than the reflected light from the object-side focal plane of the light collecting means from the reflected light reflected by the biological tissue. Has a pinhole. The pinhole is an end face of a single mode optical fiber on which a light beam from the object side focal position of the light collecting means is incident. That is, by arranging 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 condensing means, the optical fiber has a function of a pinhole used in a confocal optical system, It is possible to have a function of transmitting an observation image obtained by the confocal optical system to an external device such as a processor.
[0015]
In addition, a confocal endoscope device including any of the above-described scanning confocal probes is based on a light source that irradiates a living tissue and reflected light of the living tissue transmitted from the scanning confocal probe. The image signal generating unit can generate an image signal.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing a schematic configuration of a scanning confocal probe device 500 according to an embodiment of the present invention. The scanning confocal probe device 500 includes a scanning confocal probe 100, a processor 300, and a monitor 400.
[0017]
The operator can insert the scanning confocal probe 100 into a forceps channel of an endoscope (not shown) and obtain an observation image in the body cavity through the probe. The observation image obtained by the probe is subjected to image processing by the processor 300 and displayed on the monitor 400.
[0018]
The processor 300 includes a laser light source 310, a coupler 320, a light receiving element 330, a CPU 340, an image processing circuit 350, and an operation panel 360.
[0019]
The laser light source 310 oscillates a He—Ne laser having an oscillation wavelength of 632 nm. The laser light source used for the confocal optical system can obtain higher resolution as the wavelength is shorter. That is, the laser light source 310 is not limited to a He—Ne laser, and may be, for example, a short wavelength Ar ⁺ laser.
[0020]
The light beam oscillated from the laser light source 310 is guided to the scanning confocal probe 100 through a coupler 320 which is an optical branching device.
[0021]
The probe 100 includes an optical fiber 110, a GRIN lens (or collimator lens) 120, a pentaprism 130, a micromirror 140, an objective lens 150, and a cable 160. The optical fiber 110, the GRIN lens 120, the pentaprism 130, and the objective lens 150 are installed and fixed along the inner wall of the probe 100 previously molded into a predetermined shape. Therefore, relative positioning between the members is performed very easily and with high accuracy. The probe 100 is a side view type that irradiates the light beam from the light source 310 in a direction substantially orthogonal to the insertion direction into the body cavity, that is, observes the observation site from the side surface of the probe.
[0022]
The probe 100 is electrically and optically connected to the processor 300 by a cable 160. The optical fiber 110 is a single mode fiber that transmits a single mode. The optical fiber 110 is arranged so as to enter the probe 100 from the end of the cable 160 on the processor 300 side through the cable 160. That is, the optical fiber 110 transmits the light beam output from the processor 300 toward the GRIN lens 120. In the cable 160, the optical fiber 110 is covered with a jacket 160a.
[0023]
The GRIN lens 120 is a lens molded from an optical material whose refractive index has a gradient inside the medium, and functions as a collimator lens. That is, the light beam emitted from the optical fiber 110 enters the GRIN lens 120 and becomes a parallel light beam and is emitted toward the pentaprism 130.
[0024]
The pentaprism 130 is formed of a glass material such as BK7 or synthetic quartz. The pentaprism 130 bends the optical path of the incident light beam at a right angle by the first surface 130b and the second surface 130c whose crossing angle is set to 45 °.
[0025]
The parallel light beam emitted from the GRIN lens 120 enters the pentaprism 130 via the surface 130a. In the present specification, of the surfaces of the pentaprism 130, the surface 130a on which the light beam from the light source 310 is incident is referred to as a light beam incident end surface for convenience. The first surface 130b is a mirror surface provided with a highly reflective film such as a metal film or a dielectric multilayer film. Therefore, the light beam incident on the pentaprism 130 is reflected by the first surface 130b and then enters the micromirror 140 mounted on the second surface 130c.
[0026]
The micromirror 140 has a mirror part (not shown) and a support base (not shown) that rotatably supports the mirror part. The micromirror 140 is mounted on the pentaprism 130 by bonding the support base to the second surface 130c. Under the control of the CPU 340, the micro mirror 140 scans the incident light beam simultaneously in the X direction and the Y direction orthogonal to the X direction by rotating the mirror unit. That is, the micromirror 140 used in the present embodiment is a biaxial scanning type. The X direction and the Y direction are directions orthogonal to the optical axis of an objective lens 150 described later. The surface defined by the X direction and the Y direction substantially coincides with the surface of the observed region 10.
[0027]
The parallel light beam deflected by the micromirror 140 is incident on the pentaprism 130 again through the second surface 130c. The parallel light beam incident on the pentaprism 130 is emitted from the surface 130 d and guided to the objective lens 150. In the present specification, among the surfaces of the pentaprism 130, a surface 130d from which a parallel light beam is emitted via the micromirror 140 is referred to as a light beam emission end surface for convenience.
[0028]
Here, if the probe 100 is constituted by optical members molded using different materials, a difference occurs in the expansion coefficient of each member due to a temperature change. If the temperature characteristics are poor as described above, the positional relationship between the optical members is shifted, and the optical path of the laser beam that scans the observation target is shifted in an unexpected direction. Therefore, it becomes difficult to obtain a necessary observation image.
[0029]
Therefore, in the present embodiment, a lens molded using the same optical material as that of the pentaprism 130 is used as the objective lens 150. Thus, by unifying the optical members disposed in the probe 100 with the same optical material, there is no adverse effect due to the temperature change around the probe 100 described above. The parallel light beam emitted from the light beam emission end face 130 d of the pentaprism 130 is focused on the surface portion or the tomographic portion of the observed site 10 through the objective lens 150.
[0030]
In the present embodiment, the micromirror 140 and the objective lens 150 are disposed at a position that is in a telecentric relationship so that light is incident at a substantially right angle with respect to the observation site 10 that is the focal plane. Specifically, the micromirror 140 is disposed at the focal position when a parallel light beam is incident on the objective lens 150 from the observed region 10 side. As a result, the light beam is not obliquely incident on the observed region 10 and the light amount loss is reduced.
[0031]
The light beam condensed at the observation site 10 is reflected at the observation site 10 and enters the objective lens 150. Then, it becomes a parallel light beam by the objective lens 150 and enters the GRIN lens 120 through the same optical path as described above.
[0032]
The optical fiber 110 is a single mode fiber as described above. Therefore, the core diameter, which varies depending on the wavelength used, is very small, about 3 to 9 μm. The end face 110a of the optical fiber 110 is disposed at a position conjugate with the object side focal position of the objective lens 150. That is, only the reflected light of the light beam focused on the observed region 10 out of the light beam incident on the GRIN lens 120 is focused on the end face 110a. The light beam focused on the end face 110 a enters the optical fiber 110 and is received by the light receiving element 330 through the coupler 320.
[0033]
Note that the reflected light of the observed portion 10 other than the reflected light from the object-side focal plane in the objective lens 150 is not focused on the end face 110 a and does not enter the optical fiber 110, and thus is not transmitted to the processor 300. That is, in this embodiment, the end face 110a of the optical fiber 110 is obtained by a pinhole function that blocks light other than the reflected light from the object-side focal plane of the objective lens 150 and the optical system that the scanning confocal probe 100 has. And a function of transmitting the observed image to the processor 300.
[0034]
The light beam received by the light receiving element 330 is photoelectrically converted into an image signal and output to the image processing circuit 350. The image processing circuit 350 performs predetermined image processing on the image signal and converts the image signal into various video signals such as a composite video signal, an RGB signal, and an S video signal. When these video signals are output to the monitor 400, an observation image of the observation site 10 in the focal plane of the objective lens 150 generated by the scanning confocal probe 100 is displayed on the monitor.
[0035]
The surgeon operates the operation panel 360 included in the processor 300 to set the image such as the scanning direction and the scanning angle of the micro mirror 140. For example, the field of view of the observation image can be easily changed by changing the scanning angle of the micromirror 140 (that is, the range of the laser beam scanned at the observation site 10). When the scanning angle is small, the observation image is a small region, and when the scanning angle is large, the observation image is a large region.
[0036]
Information input to the operation panel 360 by the surgeon is transmitted to the CPU 350. The CPU 350 controls the driving of the micromirror 140 based on the transmitted information. When the micro mirror 140 is driven, the laser beam scans in the X direction or the Y direction with respect to the observation site 10 as described above. Then, the reflected light of the scanned part is transmitted to the processor 300 as an observation image. Thereby, the surgeon can selectively observe an image obtained by the scanning confocal probe 100.
[0037]
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.
[0038]
FIG. 2 is a diagram illustrating a modified example of the probe 100. The probe 100 shown in FIG. 2 omits the objective lens 150 by providing the diffraction surface D on the light beam exit end face 130 c of the pentaprism 130. The transmissive parallel flat plate 170 is provided to protect the light exit end face 130c and the diffractive surface D provided on the end face 130c. According to the modification shown in FIG. 2, the dimensions of the probe 100 in the direction orthogonal to both the X direction and the Y direction, that is, the direction in which the light beam enters the site to be observed 10 can be further reduced.
[0039]
In the above embodiment, the micromirror 140 is described as being mounted on the second surface 130c of the pentaprism 130. However, the micromirror 140 may be mounted on the first surface 130b. Furthermore, in the above embodiment, the micromirror 140 uses a biaxial scanning type, but uses two single-axis scanning micromirrors, a micromirror that can scan in the X direction and a micromirror that can scan in the Y direction. Even in this case, the same effect as the above configuration can be obtained. In this case, one single-axis scanning micromirror may be mounted on each of the first surface 130b and the second surface 130c. A single-axis scanning micromirror requires less driving space than the biaxial scanning type. Therefore, the configuration using two uniaxial scanning micromirrors has an advantage that the entire probe 100 can be further reduced in size, although the number of constituent members is increased as compared with the configuration of the above embodiment.
[0040]
In this embodiment, the He—Ne laser is used as the light source for irradiating the site 10 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, it is possible to observe the fluorescence emitted from the observed site 10.
[0041]
【The invention's effect】
As described above, in the scanning confocal probe and the scanning confocal probe apparatus of the present invention, the pentaprism, which is the light guiding means and on which the scanning means is mounted, is disposed in the space used as the optical path. Therefore, it is possible to share the space used as the optical path and the mounting space for the scanning means, and space can be saved. Thereby, the housing which is the outer shape of the probe can be made small, and the diameter of the probe can be easily reduced.
[0042]
Further, by mounting scanning means on the surface of the pentaprism, positioning between the optical members can be performed easily and with high accuracy. Accordingly, it is possible to reduce the number of assembly steps of the probe and shorten the assembly time, leading to cost reduction.
[0043]
Furthermore, each optical member constituting the probe according to the present invention is made of the same material. Thereby, the difference of the expansion coefficient of each optical element decreases. As a result, even when the temperature change received by the probe is large, it is possible to suppress the positional deviation between the optical elements due to the difference in expansion coefficient, and the temperature characteristics are improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a scanning confocal probe device according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a modification of the scanning confocal probe according to the embodiment of the present invention.
[Explanation of symbols]
100 Scanning Confocal Probe 130 Penta Prism 300 Processor 500 Scanning Confocal Probe Device

Claims (11)

A scanning confocal probe of a side view type that observes a living tissue in the body cavity by irradiating a light beam from a light source in a direction substantially orthogonal to the direction of insertion into the body cavity,
A pentaprism disposed in the optical path of the luminous flux and bending the optical path in a direction substantially orthogonal to the direction of incidence by the first surface and the second surface;
A scanning confocal probe, comprising: a scanning unit which is attached to at least one of the first surface and the second surface and scans the light beam on a living tissue in the body cavity. The scanning confocal probe according to claim 1,
2. A scanning confocal probe according to claim 1, further comprising condensing means for condensing the light beam emitted from the pentaprism on a living tissue in the body cavity. The scanning confocal probe according to claim 2,
2. The scanning confocal probe according to claim 1, wherein the condensing means is a diffractive surface provided on a light beam exit end surface of the pentaprism. The scanning confocal probe according to any one of claims 1 to 3,
The scanning confocal probe according to claim 1, wherein the scanning unit includes a biaxial scanning mirror that scans the light beam in a first direction and a second direction orthogonal to the first direction. The scanning confocal probe according to claim 4, wherein the biaxial scanning mirror is attached to either the first surface or the second surface. The scanning confocal probe according to claim 5,
Of the first surface and the second surface, a surface on which the biaxial scanning mirror is not attached is provided with a reflective film, and the scanning confocal probe is characterized in that: The scanning confocal probe according to any one of claims 4 to 6,
The scanning confocal probe according to claim 1, wherein the scanning unit is disposed at a position where a focal point is formed when a parallel light beam is incident on the condensing unit from the living tissue side. The scanning confocal probe according to any one of claims 1 to 3,
The scanning means includes a first scanning mirror that scans the light beam in a first direction, and a second scanning mirror that scans the light beam in a second direction orthogonal to the first direction. ,
The scanning confocal probe according to claim 1, wherein the first scanning mirror and the second scanning mirror are mounted on the first surface and the second surface, respectively. The scanning confocal probe according to any one of claims 2 to 8,
The condensing probe and the pentaprism are made of the same material, and the scanning confocal probe is characterized. The scanning confocal probe according to any one of claims 1 to 9,
Of the reflected light reflected by the biological tissue, has a pinhole arranged to remove reflected light other than the reflected light from the object-side focal plane of the light collecting means,
The scanning confocal probe according to claim 1, wherein the pinhole is an end face of a single mode optical fiber on which a light beam from an object-side focal position of the light collecting means is incident. A scanning confocal probe according to any one of claims 1 to 10,
A light source that emits a light beam that illuminates a living tissue;
An image signal generation unit that generates an image signal based on reflected light of the living tissue transmitted by the scanning confocal probe.

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