JP4137618B2 - Endoscope light source device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an endoscope light source device, and more particularly to a configuration of a light source device used for an endoscope that observes a specific element with light in a predetermined wavelength region.
[0002]
[Prior art]
In an endoscope apparatus (or an electronic endoscope apparatus), a light source device is used to obtain illumination light, and output light of the endoscope light source device is transmitted from a distal end portion of an endoscope (scope) by a light guide. The object to be observed is observed by irradiating illumination light from the tip.
[0003]
By the way, in endoscope apparatuses used in the medical field in recent years, observation of specific elements such as fluorescence observation, observation of oxygen saturation in blood hemoglobin, and blood vessel shape observation has been proposed. An endoscope for performing the fluorescence observation is disclosed in, for example, Japanese Patent Application Laid-Open No. 10-201707. A fluorescent substance having an affinity for a lesion such as cancer is administered into a body to be observed and output from a light source device. The fluorescence from the fluorescent substance taken into the lesion can be observed by irradiating the excitation light in the predetermined wavelength region.
[0004]
In addition, oxygen saturation in blood hemoglobin is generally measured with a pulse oximeter or the like. In this pulse oximeter, oxyhemoglobin in which hemoglobin and oxygen are combined has a high absorbance at a wavelength of 940 nm, and oxygen is absorbed. Oxygen saturation is measured by utilizing the fact that unbound hemoglobin (deoxyhemoglobin) has a high absorbance at a wavelength of 660 nm, and that the absorbances at 850 nm match. When performing image observation in consideration of the absorbance of each of such substances, for example, by irradiating light in a wavelength region centered on 578 nm which is an absorption band of hemoglobin, or by comparing this image with a normal image, It is possible to observe the difference between oxyhemoglobin and hemoglobin.
[0005]
On the other hand, FIG. 6 shows the light reflectance characteristics at wavelengths of 400 to 700 nm for oxyhemoglobin, hemoglobin, and blood, where the characteristic Ca is oxyhemoglobin, the characteristic Cb is hemoglobin, and the characteristic Cc is blood. . As understood from this figure, for example, the difference in reflectance between oxyhemoglobin (characteristic Ca) and hemoglobin (characteristic Cb) is large near the wavelength of 475 nm or 600 nm or more, and the difference in reflectance is small near 500 to 525 nm. Therefore, the difference between the two can be observed by the image when the light of these wavelengths is irradiated and the comparison of these images.
[0006]
Further, the applicant of the present application reduces the emission ratio of the red component of 600 nm or more with a red component cut filter for the purpose of clearly displaying the shape of the blood vessel in the subject to be observed, the running state, etc. from the mucous membrane. Has proposed.
[0007]
[Patent Document 1]
JP-A-10-201707 gazette
[Problems to be solved by the invention]
However, in conventional fluorescence observation, blood vessel shape observation, etc., an optical filter such as a band pass filter or a cut filter is required to obtain light of a specific wavelength, and this optical filter is unique depending on the observation purpose. Therefore, when these are performed by a single device, there is a problem that the configuration is complicated and the size and cost of the device are increased.
[0009]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an endoscope light source device that can easily obtain light in various wavelength regions according to the observation purpose without using an optical filter. There is to do.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a light guide for guiding light to the distal end portion of an endoscope and a light guide arranged on the light guide for outputting light source light to an incident end of the light guide and having axial chromatic aberration. The optical optical system and the condensing optical system or the light guide are moved in the optical axis direction, and the light guide incident end within each wavelength condensing (focal point) range on the optical axis caused by the chromatic aberration of the condensing optical system. An optical system moving means for changing the arrangement position, and by changing the relative positional relationship between the condensing optical system and the light guide by the optical system moving means, on the optical axis caused by the axial chromatic aberration. Is selected and output.
[0011]
According to the above configuration, a general condensing optical system in which chromatic aberration is removed as much as possible is used. Conversely, when a condensing optical system having large chromatic aberration is used, condensing on the optical axis ( The light of each wavelength is distributed in a predetermined light collection range (width) at the focal point position. Therefore, the present invention, for example, moves the condensing optical system and changes the position of the light guide incident end in each wavelength condensing range on the optical axis, thereby reducing the wavelength distribution (color distribution) caused by the axial chromatic aberration. The wavelength in a specific region is selected and extracted from the inside.
[0012]
Here, the wavelength region (width) selected under the above-mentioned axial chromatic aberration is determined by the degree of chromatic aberration and the diameter of the light guide incident end, etc., and can be selected by reducing the diameter of the light guide. The wavelength region to be selected can be narrowed. Conversely, if the diameter is increased, the selected wavelength region can be widened. These wavelength regions are selected according to the purpose of observation, and light of the selected wavelength region is irradiated to the object to be observed, for example, fluorescence observation, observation of oxygen saturation in blood hemoglobin, blood vessel shape observation The specific elements such as are observed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a main configuration of an endoscope light source device according to an embodiment. As shown in the drawing, a light guide connector 12 at the distal end of an endoscope cable is connected to the light source device 10. Is done. A light guide storage bar 13 is provided at the end of the light guide connector 12, and a light guide 14 is disposed from the end (14e) of the light guide storage bar 13 to the distal end of the endoscope.
[0014]
A condenser lens (lens group) 15 that is a condensing optical system is optically connected to the incident end 14 e of the light guide 14, and a light amount control plate 16 is disposed behind the condenser lens 15. A light source lamp 17 composed of a halogen lamp or a xenon lamp is attached. A cooling fan 18 for cooling the light source lamp 17 is provided in the vicinity of the light source lamp 17, and the light quantity control plate 16 is provided with a light quantity control mechanism motor 21 via connecting gears 20A and 20B.
[0015]
The condenser lens 15 is configured to move back and forth on the optical axis of the light source lamp 17. That is, the lens barrel frame (lens holding frame) 24 of the condenser lens 15 is attached to the inside of the cylindrical lens barrel receiving portion 25 so as to be movable back and forth, and is urged to the rear side (light source lamp side) by the compression spring 26. Has been. Further, a drive shaft 29 of a linear drive motor 28 is attached to a support portion (support arm) 24 a provided so as to protrude from the lens barrel frame 24, and the condenser lens 15 is compressed by the linear drive motor 28. It moves back and forth in the direction of the optical axis while receiving the urging force of 26 (against the restoring force).
[0016]
Further, although not shown, the linear drive motor 28 and the light quantity control mechanism motor 21 are driven by the control of a microcomputer or the like, and the operation panel of the endoscope, the operation panel of the processor device, etc. An operation switch is provided, and the microcomputer outputs a drive command to the linear drive motor 28 by operating the operation switch. A potentiometer or the like for detecting the movement position of the condenser lens 15 is provided, and movement control based on this position information can be performed.
[0017]
2 and 3 show the relationship between the axial chromatic aberration formed by the condenser lens 15 and the light guide. As shown in FIG. 2, the light passing through the condenser lens 15 has, for example, a violet (wavelength near 420 nm) light beam La passing through the inside due to chromatic aberration, and a green (around 500 nm) light beam Lb passing slightly outside. The light ray Lc of red (in the vicinity of 625 nm) passes through the outermost side. As a result, the wavelength distribution of light is generated in the condensing range (width) D ₁ on the optical axis 100 at the focal length of the condenser lens 15. Thus, by arranging the entrance end 14e of the light guide 14 to a predetermined position of the condenser range D _1, it is possible to select light of a desired wavelength region.
[0018]
3A shows an enlarged view of the vicinity of the light guide incident end 14e. In FIG. 3A, light having a wavelength of about 500 nm of the light beam Lb is selected. Here, the light guide 14 is selected. If the set to the incident end 4c narrow diameter _{r 1,} for example 500nm light in a narrow wavelength region _{d 1} as the center is taken out of a wide wavelength range d around the 500nm If the incident end 4c and thick diameter _{r 2 2} light is extracted. FIG. 4 shows the incidence rate (transmittance) at the light guide 14 at this time. In the case of the thin diameter r ₁ , light having a wavelength in a narrow region of the characteristic C ₁ is selected, and the thick diameter is selected. for r ₂ light of a wide wavelength characteristics C ₂ area is selected. Note that the angles of the light beams La to Lc described with reference to FIG. 3A with respect to the optical axis 100 are set to be equal to or smaller than the opening angle (NA) of the light guide 14. For example, assuming that the angle αa of the light beam La with respect to the optical axis 100 is the maximum angle, the relationship with the opening angle β of the light guide 14 in FIG. 3B is configured to satisfy αa ≦ β.
[0019]
The embodiment is configured as described above. When the operation switch for observing a specific element is pressed, the linear drive motor 28 is activated, and the condenser lens 15 is moved to a predetermined position on the optical axis 100 via the drive shaft 29. This movement of the condenser lens 15, as shown for example in FIG. 5, when the combined P ₁ position of each wavelength condensing range D ₁ of the axial chromatic aberration in the light guide incident end 14e, and the center wavelength lambda ₁ light in a predetermined wavelength region is selected to be, if the combined P ₂ located in the light guide incident end 14e, the predetermined wavelength region around a wavelength lambda _2, when the combined P ₃ located on the light guide incident end 14e , Light in a predetermined wavelength region centered on the wavelength λ ₃ is selected.
[0020]
For example, in the case of fluorescence observation, by moving the condenser lens 15 and selecting light in a predetermined region having a wavelength of 780 nm or less including excitation light, it is possible to observe the portion where the fluorescent material is taken in. In the case of observing oxygen saturation in blood hemoglobin, for example, when irradiating light in a predetermined region centered on a wavelength of 578 nm, which is an absorption band of hemoglobin, or the characteristics Ca and hemoglobin of oxyhemoglobin shown in FIG. It is possible to observe the oxygen saturation, the distribution of oxyhemoglobin, and the like by comparing images when irradiating light in a wavelength region having a large difference in the characteristic Cb.
[0021]
Furthermore, in the blood vessel shape observation, a reddish state in the body to be observed is selected by selecting a wavelength region that halves the light in the red wavelength region (may be 1/3 or the like), for example, light having a wavelength of 660 nm or less. Thus, it becomes possible to observe the shape of the blood vessel, the running state, etc. satisfactorily with sufficient contrast.
[0022]
In the above embodiment, the condenser lens 15 which is a condensing optical system is moved, but the incident end of the light guide 14 may be configured to be movable. For example, as a structure in which a dedicated light incident part similar to the incident end 14e is movably provided in the light source device 10 and this light incident part is optically coupled to the light guide 14 on the connector 12 side, the condenser lens 15 and the light The relative positional relationship with the guide dedicated light incident portion can be changed.
[0023]
In addition, the conventional normal light output unit is used as the first light output unit, and the light output unit that maintains the relationship between the condenser lens 15 and the light guide incident end 14e in the above embodiment is used as the second light output unit. It is also possible to provide two systems of light output units, mix the light of the first and second light output units with an optical coupler, and irradiate the object to be observed through the light guide 14.
[0024]
【The invention's effect】
As described above, according to the present invention, a condensing optical system having axial chromatic aberration is used as a condensing optical system that outputs light source light to the light guide incident end, and the condensing optical system or the light guide is moved in the optical axis direction. By moving and changing the arrangement position of the light guide incident end within each wavelength condensing range on the optical axis, light of any wavelength on the optical axis caused by axial chromatic aberration is selected and output. Without using an optical filter, it is possible to easily obtain light in various wavelength regions according to the purpose of observation, and to observe a specific element satisfactorily. Further, there is an advantage that the structure is simple and the apparatus is not increased in size and cost.
[Brief description of the drawings]
FIG. 1 is a diagram showing a main configuration of an endoscope light source device according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating axial chromatic aberration and a relationship between the chromatic aberration portion and the light guide in the condenser lens (condensing optical system) of the example.
3 is an enlarged view of an axial chromatic aberration generation unit of the condenser lens of FIG. 2;
4 is a diagram showing a wavelength region (incident rate with respect to wavelength) selected in the positional relationship of FIG. 3 in the embodiment.
FIG. 5 is a diagram showing a positional relationship of light guides arranged in each wavelength condensing range of the condenser lens of Example.
FIG. 6 is a characteristic diagram showing the reflectance of each wavelength with respect to oxyhemoglobin, hemoglobin, and blood.
[Explanation of symbols]
10: Light source device,
14 ... light guide, 14e ... incident end,
15 ... condenser lens, 17 ... light source lamp,
24 ... Lens barrel frame, 25 ... Lens barrel receiver,
28: Linear drive motor,
D _1. Each wavelength condensing range.

Claims (1)

A light guide to guide light to the endoscope tip,
A condensing optical system arranged to output light source light to the incident end of the light guide and having axial chromatic aberration,
Optical for moving the condensing optical system or the light guide in the optical axis direction and changing the arrangement position of the light guide incident end within each wavelength condensing range on the optical axis caused by the chromatic aberration of the condensing optical system System moving means,
By changing the relative positional relationship between the condensing optical system and the light guide by the optical system moving means, it is possible to select and output an arbitrary wavelength distribution light on the optical axis caused by the axial chromatic aberration. Endoscope light source device.

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