JP4589670B2 - Endoscope light source device - Google Patents

Description

  The present invention generates visible light and excitation light by using an endoscope to enable normal observation of a body cavity wall by visible light and fluorescence observation by autofluorescence generated by exciting living tissue on the body cavity wall. The present invention relates to an endoscope light source device that is incident on an endoscope light guide.

  This type of endoscope light source device is disclosed in Patent Documents 1 and 2, for example. In FIG. 1 of Patent Document 1, parallel white light, a white light source 21 and an excitation light source 22 that emit excitation light, a dichroic mirror 24 that synthesizes an optical path of light from these light sources, and a wheel provided with RGB color filters. A condensing lens C for condensing W, parallel RGB color light and excitation light and making them incident on the light guide 12 of the endoscope is provided.

FIG. 2 of Patent Document 2 shows parallel white light, white light source unit 21 and excitation light source unit 22 that emit excitation light, and condensing lenses C1 and C2 that use light from these light source units as convergent light, respectively. In addition, a prism 26 for synthesizing these optical paths in the optical path of the convergent light is provided. An adjustment lens 13 a is provided on the end surface of the light guide 13, and the converged white light and excitation light are further refracted to enter the light guide 13.
JP 2002-65602 A FIG. Japanese Patent Laid-Open No. 2003-61909 FIG.

  However, each of the above publications does not disclose a configuration in which a plurality of types of light guides having different NAs (numerical apertures) are switched and connected. Quartz fibers for excitation light and ultraviolet transmission type multi-component fibers used for fluorescence observation have high light transmittance from the ultraviolet region to a wavelength of about 450 nm, but can illuminate only a narrow region because the NA is relatively small. On the other hand, the multi-component fiber for white light has a low light transmittance in the above region, but can illuminate a wide region because the NA is relatively large. Therefore, it is advantageous to use an excitation light fiber as a light guide for endoscopes that perform fluorescence observation. However, when taking a color image with white light illumination without performing fluorescence observation, a white light guide is used. It is desirable to use multicomponent fibers for light.

  In fluorescence observation, there are a mode for observing only the fluorescence image and a mode for observing the fluorescence image and the reference image by image processing. In the latter case, the fluorescence image obtained by photographing autofluorescence and white light are used. In order to compare with a reference image taken by illumination, excitation light and white light are alternately incident on the light guide for excitation light. Further, when observing a color image with an endoscope that does not perform fluorescence observation, white light is incident on a multi-component fiber for white light. For this reason, as a light source device, white light is incident on both light guides. When using a light guide for white light, it is possible to illuminate a wide range by making a light beam incident with a relatively large NA in accordance with the NA of the light guide. On the other hand, when white light is incident on a light guide for excitation light having a small NA, if light is incident at a large NA as in the case of using a light guide for white light, a part of light rays having a large incident angle is obtained. Passes through the boundary between the core and clad of the light guide for excitation light, generates heat on the outer surface of the clad layer, damages the light guide, or heats the light source insertion part of the light guide to the endoscope There is a problem that there is a risk of burns when the is removed from the light source.

  The present invention has been made in view of the above-described problems of the prior art. When a light guide for white light is used, a wide range can be illuminated and a light guide for excitation light is used. An object of the present invention is to provide an endoscope light source device capable of suppressing the generation of heat.

  An endoscope light source device according to the present invention uses visible light for observing a body cavity wall and excitation light for exciting a living tissue on the body cavity wall to emit autofluorescence as a light guide for the endoscope. In the configuration to be introduced, it is synthesized by a visible light source that emits visible light, an excitation light source that emits excitation light, an optical path synthesis element that synthesizes an optical path of excitation light emitted from the excitation light source and an optical path of visible light, and an optical path synthesis element. A converging lens that collects visible light and excitation light and enters the light guide, and a convergence angle switch that switches the convergence angle of visible light incident on the light guide according to the numerical aperture of the light guide. Means.

  As the convergence angle switching means, means for changing the beam diameter of visible light between the visible light source and the condenser lens in accordance with the numerical aperture of the light guide, or the focal point of the condenser lens in accordance with the numerical aperture of the light guide. By changing the distance, means for changing the convergence angle of visible light incident on the light guide can be used.

  When changing the beam diameter, an aperture stop is selectively inserted into the optical path of visible light between the visible light source and the condenser lens, and when the numerical aperture of the light guide is small, an aperture stop is inserted into the optical path. When the numerical aperture of the light guide is large, an aperture switching mechanism that retracts the aperture stop from the optical path may be provided. Alternatively, a variable aperture may be used to change the aperture diameter according to the numerical aperture. Further, two positive and negative lenses or a light beam diameter conversion optical system combining two positive lenses may be inserted into the optical path and retracted.

  When changing the focal length of the condensing lens, a plurality of condensing lenses that are selectively inserted into the optical path are different from each other, and a condensing lens with a long focal length when the numerical aperture of the light guide is small. A lens switching mechanism that is arranged in the optical path and that has a short focal length in the optical path when the numerical aperture of the light guide is large may be provided. Alternatively, the focal length may be changed according to the numerical aperture using a variable focal length lens.

  The aperture switching mechanism or lens switching mechanism detects the numerical aperture of the light guide mounted on the endoscope and automatically inserts / retracts the aperture diaphragm into the optical path according to the numerical aperture, or the numerical aperture A condensing lens having a focal length suitable for the above may be automatically arranged in the optical path.

  When the aperture stop is inserted / retracted, the aperture stop is configured to move integrally with the optical path combining element, and the aperture stop and the optical path combining element are integrally inserted into the optical path by the stop switching means, or retracted. You may make it make it.

  According to the present invention, since the NA of visible light can be changed according to the numerical aperture of the light guide, the numerical aperture of incident light is set to be large when performing color photography using the light guide for visible light. Can illuminate a wide area, and in the case of fluorescent imaging using a light guide for excitation light, generation of heat in the light guide can be prevented by setting the numerical aperture of incident light small. .

  Hereinafter, three examples of an endoscope light source device according to the present invention will be described with reference to the drawings. The light source device of any of the embodiments uses a visible light (white light) for observing the body cavity wall and an excitation light for exciting the living tissue on the body cavity wall to emit autofluorescence. It is for introduction to.

  FIG. 1 is an external view of an endoscope system including an endoscope light source device according to Embodiment 1 of the present invention, and FIG. 2 is a block diagram showing the internal configuration thereof. As shown in FIG. 1, the endoscope system includes a fluorescence observation endoscope 10, a light source device 20, and a monitor 60.

  The fluorescence observation endoscope 10 is obtained by adding a modification for fluorescence observation to a normal electronic endoscope. The fluorescence observation endoscope 10 is formed in an elongated shape so as to be inserted into a body cavity, and is provided with a bending portion that can be bent at a distal end. A light guide flexible tube 10c for connecting the operation unit 10b and the light source device 20 and the light guide flexible member 10a, an operation unit 10b having an angle knob for operating the bending portion of the insertion unit 10a, and the like. A connector 10d provided at the proximal end of the tube 10c is provided.

  On the other hand, on the front surface of the light source device 20, a key switch 22 for turning on and off the main power source of the light source device 20 and a switch panel 23 on which various operation switches are arranged are provided.

  Hereinafter, detailed configurations of the fluorescence observation endoscope 10 and the light source device 20 will be described in order according to FIG. A light distribution lens 11 and an objective lens 12 are provided on the distal end surface of the insertion portion 10 a of the fluorescence observation endoscope 10. Then, inside the insertion portion 10 a, the light is emitted from an imaging element 13 such as a CCD image sensor that captures an image of a subject formed by the objective lens 12, a drive circuit 15 that drives the imaging element 13, and the objective lens 12. A laser light cut filter 14 for removing a wavelength component corresponding to the laser light for fluorescence excitation described later from the light is incorporated.

  A signal cable 18 for transmitting an image signal output from the image sensor 13 and processed by the drive circuit 15 is routed through the insertion portion 10a, the operation portion 10b, and the light guide flexible tube 10c, and is connected to the connector 10d. It is connected to a connector pin 31a formed on the end face.

  In parallel with the signal cable 18, in the insertion portion 10 a, the operation portion 10 b and the light guide flexible tube 10 c, quartz fiber or ultraviolet transmission type multi-component fiber having a high light transmittance from the ultraviolet region to a wavelength of about 450 nm. The light guide 16 for excitation light configured by bundling a large number of them is passed through. The distal end of the light guide 16 for excitation light faces the light distribution lens 11 in the distal end portion of the insertion portion 10a, and the proximal end thereof is fixed in a state where it protrudes from the end face of the connector 10d and is inserted into the light source device 20. ing.

  Further, a ROM (Read Only Memory) 17 storing identification information indicating the attributes of the endoscope is built in the connector 10d, and each terminal of the ROM 17 is connected to a connector pin 31b. The identification information stored in the ROM 17 of the fluorescence observation endoscope 10 includes the value of the numerical aperture (NA) of the built-in excitation light guide 16. Note that a normal electronic endoscope (not shown) that can be used in place of the fluorescence observation endoscope 10 uses a multi-component fiber having high white light transmittance instead of the excitation light guide 16. The point that the light guide for white light configured by bundling is incorporated, the point that the laser light cut filter 14 is not provided, and the point that the identification information stored in the ROM 17 includes the value of NA of the light guide for white light Except for this, it has the same configuration as the fluorescence observation endoscope 10.

  The light source device 20 includes white light for observing the body cavity wall on the end face of the excitation light guide 16 for the fluorescence observation endoscope 10 and excitation light for exciting the living tissue on the body cavity wall to emit autofluorescence. Are selectively introduced, and the image data received from the drive circuit 15 through the connector pin 31a of the fluorescence observation endoscope 10 is processed to generate a video signal, which is output to the monitor 60.

  The optical system of the light source device 20 according to the first embodiment includes a white light source (discharge tube lamp) 30 that emits white light and a reflector (parabolic surface) that is a converging optical system that converts the white light emitted from the white light source 30 into a substantially parallel light beam. Mirror) 31, an aperture stop 32 that reduces the beam diameter of the white light that has been collimated by the reflector 31, and the white light whose beam diameter has been reduced by the aperture stop 32 is collected to concentrate the light guide 16 for excitation light. And a condensing lens 33 to be incident on.

  In addition, the light source device 20 includes a semiconductor laser 40 as an excitation light source that emits excitation light, and a collimator lens 41 that collimates the divergent light emitted from the semiconductor laser 40. The excitation light is light having a short wavelength of about 450 nm from the ultraviolet region that excites the autofluorescence of the living body.

  The optical path from the white light source 30 to the excitation light guide 16 is linear, and the optical path of the excitation light that intersects the optical path perpendicularly is synthesized by a dichroic mirror 51 that is an optical path synthesis element. That is, the dichroic mirror 51 combines the optical path of the excitation light emitted from the excitation light source and the optical path of the white light. In this example, the dichroic mirror 51 has a characteristic of transmitting light having a specific wavelength or more and reflecting light having a specific wavelength or less, thereby transmitting most of the white light and reflecting the excitation light.

  Between the white light source 30 and the aperture stop 32, an infrared cut filter 34 that cuts infrared rays and transmits visible light is disposed. A rotating wheel 52 is disposed between the aperture stop 32 and the dichroic mirror 51 as a shutter for intermittently turning on and off white light. As shown in FIG. 3, the rotating wheel 52 has two fan-shaped windows 52 </ b> H having a central angle of 90 ° that are point-symmetric about the center. The size of the window 52H is set larger than the diameter of the white light, and the white light is intermittently turned on and off by driving the motor 53 and rotating the rotating wheel 52.

  Note that the aperture stop 32, the dichroic mirror 51, the rotating wheel 52, and the motor 53 surrounded by a broken line in FIG. 2 are integrated as a unit 50 in the vertical direction (direction perpendicular to the optical path of white light) in FIG. As shown in FIG. 2, the aperture stop 32, the dichroic mirror 51, and the rotary wheel 52 are arranged in the optical path, and as shown in FIG. Switching between the saved position is possible.

  The light source device 20 includes a lamp power supply 71 for supplying current to the white light source 30, a laser driver 72 for driving the semiconductor laser 40, a switching mechanism 73 for sliding the unit 50, and a drive circuit 15 connected to the connector pin 31a. And a video signal processing circuit 74 for processing the image data received from the video signal to generate a video signal, and a system controller 70 for controlling the whole.

  The system controller 70 controls the lamp power supply 71 and the laser driver 72 based on the settings of various switches arranged on the switch panel 23 to control the emission and stop of white light and excitation light, and the video signal processing circuit 74. Controls image processing by. Further, the system controller 70 reads the identification information from the ROM 17 connected to the connector pin 31b, and controls the switching mechanism 73 based on this identification information to slide the unit 50.

  Next, the operation of the endoscope system according to the first embodiment configured as described above will be described. First, the operation in the case where a lesion is displayed on the monitor 60 by fluorescence observation will be described.

  In the case of fluorescence observation, as shown in FIG. 2, the fluorescence observation endoscope 10 is connected to the light source device 20, the key switch 22 is turned on, and the main power supply is turned on. The system controller 70 reads from the identification information in the ROM 17 that the connected fluorescence observation endoscope 10 and the NA value of the excitation light guide 16 are read. As a result, since it is found that the NA of the light guide is a relatively small value, the switching mechanism 73 is controlled to insert the unit 50 including the aperture stop 32 into the optical path as shown in FIG. Thereby, the diameter of the white light is limited to be small, and the convergence angle of the white light is set in accordance with the NA of the excitation light guide 16.

  Subsequently, when the insertion portion 10a of the fluorescence observation endoscope 10 is inserted into the body cavity and an observation start switch (not shown) disposed on the switch panel 23 is turned on, the system controller 70 controls the lamp power supply 71. Then, the white light source 30 is caused to emit light, the motor 53 is controlled to rotate the rotating wheel 52, and the semiconductor laser 40 is switched on and off. That is, the semiconductor laser 40 is turned off at the timing when the window 52H of the rotating wheel 52 is positioned in the optical path (timing when white light is transmitted), and the timing when the portion other than the window of the rotating wheel 52 is positioned in the optical path (white light is transmitted). The semiconductor laser 40 is turned on at the timing of being cut off. As a result, white light emitted from the white light source 10 is intermittently transmitted through the dichroic mirror 51 and enters the excitation light guide 16, and the excitation light from the semiconductor laser 40 is reflected by the dichroic mirror 51 to be white. The light enters the excitation light guide 16 alternately and intermittently.

  The imaging device 13 provided at the distal end of the fluorescence observation endoscope 10 alternately captures an image in a body cavity illuminated with white light and an image due to autofluorescence emitted by a tissue excited by excitation light. The image signal output from the imaging device 13 is input to the video signal processing circuit 74 via the drive circuit 15 and the signal line 18, and the video signal processing circuit 74 calculates the fluorescence image data and the reference image data. As a result, a specific image in which the lesion is emphasized is generated and displayed on the monitor 60.

  On the other hand, when illuminating and observing the body cavity wall with white light, the fluorescence observation endoscope 10 is removed, a normal electronic endoscope is connected to the light source device 20, the key switch 22 is turned on, and the main power supply is turned on. throw into. Based on the identification information of the ROM built in the electronic endoscope, the system controller 70 determines that the normal electronic endoscope is connected and the NA value of the built-in white light guide. read. As a result, since it is found that the NA of the light guide is a relatively large value, the switching mechanism 73 is controlled to retract the unit 50 including the aperture stop 32 outside the optical path as shown in FIG. As a result, the diameter of the white light is greatly changed, and the convergence angle of the white light is set in accordance with the NA of the white light light guide 19.

  Subsequently, when the insertion portion 10a of the fluorescence observation endoscope 10 is inserted into the body cavity and an observation start switch (not shown) disposed on the switch panel 23 is turned on, the system controller 70 controls the lamp power supply 71. Then, the white light source 30 emits light. However, both the motor 53 and the semiconductor laser 40 remain off. Thereby, the white light emitted from the white light source 10 continuously enters the light guide 19 for white light. An image sensor provided at the tip of the electronic endoscope captures an image of the body cavity illuminated with white light. The image signal output from the imaging device is input to the video signal processing circuit 74, and the video signal processing circuit 74 generates a normal observation image based on the data of the normal image and displays it on the monitor 60.

  That is, the light source device 20 of the first embodiment is configured to switch the convergence angle of the white light incident on the light guide by using the aperture stop and changing the light beam diameter of the white light according to the NA of the light guide. In addition, the aperture stop is automatically inserted into the optical path or retracted based on the identification information stored in the ROM. Here, the aperture stop 32, the switching mechanism 73, and the system controller 70 constitute a convergence angle switching means, and the switching mechanism 73 and the system controller 70 constitute an aperture switching mechanism.

  If a dichroic mirror 51 is arranged in the optical path of white light at the time of photographing a color image with white light, a component on the short wavelength side included in the white light is reflected by the dichroic mirror 51 and becomes a light guide for white light. The color reproducibility of the image data captured by the image sensor without being incident is deteriorated. Further, in order to place the rotating wheel 52 in the optical path during normal observation, it is necessary to stop the rotating wheel 52 at a position where the window 52H coincides with the optical path. Have difficulty. Therefore, during normal observation, the dichroic mirror 51 and the rotating wheel 52 are retracted from the optical path as an integral unit 50 together with the aperture stop 32.

  FIG. 5 is a block diagram illustrating an internal configuration of an endoscope system that includes the endoscope light source device according to the second embodiment of the present invention. As shown in FIG. 5, the endoscope system includes a fluorescence observation endoscope 10, a light source device 20 a, and a monitor 60. The fluorescence observation endoscope 10 is the same as that shown in the first embodiment. Also, since the endoscope light source device 20a has many common parts with the device of the first embodiment, the corresponding members are denoted by the same reference numerals, and redundant description is omitted. The difference from the first embodiment is that the first and second condenser lenses 33a and 33b having different focal lengths are used as a means for changing the convergence angle of white light. .

  The optical system of the light source device 20a according to the second embodiment includes a white light source 30, a reflector 31, and a first condenser lens that condenses the white light that has been collimated by the reflector 31 and enters the light guide 16 for excitation light. 33a and a second condenser lens 33b. The light source device 20a includes a semiconductor laser 40 that emits excitation light, and a collimator lens 41a that converts the divergent light emitted from the semiconductor laser 40 into parallel light.

  The optical path from the white light source 30 to the excitation light guide 16 is linear, and the optical path of the excitation light that intersects the optical path perpendicularly is synthesized by the dichroic mirror 51a.

  An infrared cut filter 34 is disposed between the white light source 30 and the dichroic mirror 51a. A rotating wheel 52a is disposed between the infrared cut filter 34 and the dichroic mirror 51a. The rotating wheel 52a of the second embodiment is designed to be larger than that of the first embodiment in accordance with the light beam diameter of white light, but the basic configuration is the same as that of the rotating wheel 52 of the first embodiment shown in FIG. is there.

  Note that the dichroic mirror 51a, the rotating wheel 52a, the motor 53, and the first and second condenser lenses 33a and 33b surrounded by a broken line in FIG. 5 are integrally slid in the vertical direction in FIG. 5 as a unit 50a. As shown in FIG. 5, the first condensing lens 33a, the dichroic mirror 51a and the rotating wheel 52a having a long focal length as shown in FIG. 5 are disposed in the optical path, and the focal length as shown in FIG. The second condensing lens 33b having a short length can be switched between a position where the dichroic mirror 51a and the rotating wheel 52a are retracted from the optical path.

  In the light source device 20a, a lamp power supply 71 for supplying current to the white light source 30, a laser driver 72 for driving the semiconductor laser 40, a switching mechanism 73a for sliding the unit 50a, and image data received from the drive circuit 15 are processed. And a video signal processing circuit 74 for generating a video signal, and a system controller 70 for controlling the whole. The system controller 70 reads the identification information from the ROM 17 connected to the connector pin 31b, and controls the switching mechanism 73 based on this identification information to slide the unit 50a.

  Next, the operation of the endoscope system according to the second embodiment configured as described above will be described. In the case of fluorescence observation, as shown in FIG. 5, the fluorescence observation endoscope 10 is connected to the light source device 20, the key switch 22 is turned on, and the main power supply is turned on. The system controller 70 reads from the identification information in the ROM 17 that the connected fluorescence observation endoscope 10 and the NA value of the excitation light guide 16 are read. As a result, since the NA of the light guide is found to be a relatively small value, the switching mechanism 73a is controlled to set the unit 50a so that the first condenser lens 33a is arranged in the optical path. Thereby, the convergence angle of the white light is set in accordance with the NA of the excitation light guide 16. Control of each light source and processing of image data in fluorescence observation are the same as in the first embodiment.

  On the other hand, when illuminating and observing the body cavity wall with white light, the fluorescence observation endoscope 10 is removed, a normal electronic endoscope is connected to the light source device 20a, the key switch 22 is turned on, and the main power supply is turned on. throw into. From the identification information of the ROM built in the electronic endoscope, the system controller 70 is connected to the normal electronic endoscope, and the NA value of the built-in white light guide 19 Read. As a result, since it is found that the NA of the light guide is a relatively large value, the switching mechanism 73a is controlled so that the second condenser lens 33b is arranged in the optical path as shown in FIG. Set the unit 50a. At the same time, the dichroic mirror 51a and the rotating wheel 52a are retracted outside the optical path. Thereby, the convergence angle of the white light is set in accordance with the NA of the white light guide 19. Control of each light source and processing of image data in normal observation are the same as in the first embodiment.

  That is, the light source device 20a according to the second embodiment is configured to switch the convergence angle of white light according to the NA of the light guide, using a plurality of condensing lenses having different focal lengths, and stored in the ROM. In this configuration, the condenser lens is automatically changed based on the identification information. Here, the first and second condenser lenses 33a and 33b, the switching mechanism 73a, and the system controller 70 constitute a convergence angle switching means, and the switching mechanism 73a and the system controller 70 constitute a lens switching mechanism. ing.

7 and 8 are explanatory diagrams showing the configuration of the optical system that is the main part of the endoscope light source device according to the third embodiment of the present invention. Since there are many common parts with the apparatus of Example 1, the same code | symbol is attached | subjected to a corresponding member and the overlapping description is abbreviate | omitted. The difference from the first embodiment is that, as a means for changing the convergence angle of white light, in place of the aperture stop 32 of the first embodiment, a light beam diameter converting optical system 35 composed of two positive and negative lenses 35a and 35b. Is inserted into the optical path or retracted.

  The optical system of the light source device according to the third embodiment includes a white light source 30, a reflector 31, and a condensing lens 33 that condenses the white light that has been collimated by the reflector 31 and enters the light guide 16 for excitation light. Yes. The light source device also includes a semiconductor laser 40 that emits excitation light, and a collimator lens 41a that converts the divergent light emitted from the semiconductor laser 40 into parallel light.

  The optical path from the white light source 30 to the excitation light guide 16 is linear, and the optical path of the excitation light that intersects the optical path perpendicularly is synthesized by the dichroic mirror 51. An infrared cut filter 34 is disposed between the white light source 30 and the dichroic mirror 51. Between the infrared cut filter 34 and the dichroic mirror 51, the light beam diameter converting optical system 35 and the rotating wheel 52 are arranged. The light beam diameter conversion optical system 35 is configured to return the light beam once converged by the positive lens 35a to parallel light by the negative lens 35b. In addition to such a combination of positive and negative lenses, two positive lenses may be combined. .

  The dichroic mirror 51, the rotating wheel 52, the motor 53, and the light beam diameter conversion optical system 35 surrounded by a broken line in FIG. 7 are configured to be integrally slidable in the vertical direction in FIG. 7 as a unit 50b. 7 can be switched between a position where the optical elements in the unit 50b are arranged in the optical path as shown in FIG. 7 and a position where these optical elements are retracted from the optical path as shown in FIG.

  Next, the operation of the endoscope light source device of the third embodiment configured as described above will be described. In the case of fluorescence observation, a fluorescence observation endoscope is connected to the light source device, and as shown in FIG. 7, the unit 50b is arranged so that the light beam diameter conversion optical system 35, the rotating wheel 52, and the dichroic mirror 51 are arranged in the optical path. Set. Thereby, the convergence angle of the white light is set in accordance with the NA of the excitation light guide 16.

  On the other hand, when illuminating and observing the body cavity wall with white light, a normal electronic endoscope is connected to the light source device, and as shown in FIG. 8, a light beam diameter conversion optical system 35, a rotating wheel 52, a dichroic mirror. The unit 50b is set so that 51 is arranged outside the optical path. Thereby, the convergence angle of the white light is set in accordance with the NA of the white light guide 19.

  That is, the light source device of the third embodiment uses the light beam diameter conversion optical system 35 to change the convergence angle of the white light incident on the light guide by changing the light beam diameter of the white light according to the NA of the light guide. It is a configuration. In switching, the light beam diameter converting optical system 35 is automatically inserted into the optical path or retracted based on the identification information stored in the endoscope built-in ROM, as described in the first embodiment. Can be made. Although only the light beam diameter conversion optical system 35 is shown here, the light source device of the third embodiment is also provided with a switching mechanism and system controller similar to those of the first embodiment as convergence angle switching means, of which the switching mechanism and The system controller constitutes an optical system switching mechanism.

  In each of the above embodiments, only an example in which a single semiconductor laser is used as an excitation light source has been described. However, laser light from a plurality of semiconductor lasers may be synthesized and used, or a solid laser or gas laser may be used. Alternatively, a discharge tube such as a xenon lamp can be used. However, when a discharge tube is used, a shutter similar to the rotating wheel is also required in the optical path for excitation light.

  In each of the above embodiments, the optical path of the white light is made straight and the optical path of the excitation light is folded by the optical path synthesis element. Conversely, the optical path of the excitation light is made straight and the optical path of the white light is bent. You may do it. In the latter case, a dichroic mirror that reflects light having a specific wavelength or more and transmits light having a specific wavelength or less may be used as the optical path combining element.

1 is an external view of an endoscope system configured to include an endoscope light source device according to Embodiment 1 of the present invention. FIG. It is a block diagram which shows the internal structure of the endoscope system shown by FIG. 1, and shows the arrangement | positioning at the time of fluorescence observation. FIG. 3 is a front view of a rotating wheel provided in the optical system of FIG. 2. It is explanatory drawing which shows the arrangement | positioning at the time of normal observation of the optical system of FIG. It is a block diagram which shows the internal structure of the endoscope system comprised including the light source device for endoscopes which concerns on Example 2 of this invention, and shows the arrangement | positioning at the time of fluorescence observation. It is explanatory drawing which shows the arrangement | positioning at the time of normal observation of the optical system of FIG. It is explanatory drawing which shows the optical system of the light source device for endoscopes which concerns on Example 3 of this invention, and is explanatory drawing which shows arrangement | positioning at the time of fluorescence observation. It is explanatory drawing which shows the arrangement | positioning at the time of normal observation of the optical system of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fluorescence observation endoscope 16 Light guide for excitation light 19 Light guide for white light 20, 20a Light source device 30 White light source 31 Reflector (parabolic mirror)
32 Aperture stop 34 Infrared cut filter 33, 33a, 33b Condensing lens 40 Semiconductor laser (excitation light source)
41 Collimating lens 51, 51a Dichroic mirror 52, 52a Rotating wheel 53 Motor 60 Monitor 70 System controller 71 Lamp power supply 72 Laser driver 73, 73a Switching mechanism 74 Video signal processing circuit

Claims (6)

An endoscope light source device for introducing visible light for observing a body cavity wall and excitation light for exciting a living tissue on the body cavity wall to emit autofluorescence into a light guide of the endoscope. And
A visible light source that emits the visible light;
An excitation light source that emits the excitation light;
An optical path synthesis element that synthesizes the optical path of the excitation light emitted from the excitation light source and the optical path of the visible light;
A condensing lens disposed in an optical path synthesized by the optical path synthesizing element, and condensing the visible light and the excitation light and entering the light guide;
Detecting means for detecting the numerical aperture of the light guide;
A convergence angle switching means for automatically switching the convergence angle of visible light incident on the light guide by inserting or retracting an optical element in the optical path in accordance with the numerical aperture of the light guide detected by the detection means. An endoscope light source device comprising: The said convergence angle switching means changes the light beam diameter of the said visible light between the said visible light source and the said condensing lens according to the numerical aperture which the said detection means detected . Endoscope light source device. The convergence angle switching means includes
An aperture stop selectively inserted in the optical path of the visible light between the visible light source and the condenser lens;
An aperture switching mechanism is provided that inserts the aperture stop into the optical path when the numerical aperture detected by the detection means is small, and retracts the aperture stop from the optical path when the numerical aperture of the light guide is large. Item 3. The endoscope light source device according to Item 2. The aperture stop is configured to move integrally with the optical path combining element;
4. The endoscope light source device according to claim 3 , wherein the aperture switching unit inserts or retracts the aperture stop and the optical path combining element integrally in the optical path. The convergence angle switching means includes
A plurality of said condenser lens to a focal length that is selectively inserted into the optical path are different from each other,
A lens having a long focal length disposed in the optical path when the numerical aperture detected by the detecting means is small, and a lens having a short focal length disposed in the optical path when the numerical aperture detected by the detecting means is large. The endoscope light source device according to claim 1 , further comprising a switching mechanism. The convergence angle switching means includes
A beam diameter converting optical system that is selectively inserted into the optical path of the visible light between the visible light source and the condenser lens;
An optical system switching mechanism that inserts the light beam diameter converting optical system into the optical path when the numerical aperture detected by the detecting means is small, and retracts the light beam diameter converting optical system from the optical path when the numerical aperture detected by the detecting means is large. The endoscope light source device according to claim 2, further comprising: