JP5848116B2 - Light source device - Google Patents

Description

  The present invention relates to a light source device that includes a light source that emits irradiation light that is irradiated to an observed portion, and in particular, emits light to a light guide that guides and emits incident light while repeating side reflection. The present invention relates to an incident light source device.

  Conventionally, endoscope systems for observing tissue in a body cavity are widely known, and a normal image is obtained by imaging a portion to be observed in a body cavity by irradiation with white light, and this normal image is displayed on a monitor screen. Electronic endoscope systems have been widely put into practical use.

  As one of such endoscope systems, for example, in order to observe blood vessels under fat and blood flow, lymph vessels, lymph flow, bile duct runs, bile flow and the like that do not normally appear on an image, An endoscope system has been proposed in which ICG (Indocyanine Green) is introduced into an observation unit, and a fluorescence image of ICG is acquired by irradiating the observation unit with near-infrared excitation light. In addition, an endoscope system has been proposed in which autofluorescence emitted from an observed portion is detected by irradiating the observed portion with excitation light to acquire a fluorescent image.

  In such an endoscope system for acquiring a fluorescent image, a laser light source, a light emitting diode, or the like is used as a light source for emitting excitation light, and the excitation light emitted from such a light source is used as a light source such as an optical fiber. The observation portion is irradiated with excitation light by being guided by the guide.

JP 2002-175702 A

  Here, in an endoscope system that captures a fluorescent image as described above, for example, a normal method in which the excitation light emitted from the light source matches the optical axis direction of the light guide with the optical axis direction of the excitation light. When the light is incident on the light guide, an illuminance distribution in which the illuminance at the central portion is large and the illuminance is small at the peripheral portion is obtained, and excitation light having a uniform illuminance distribution cannot be irradiated to the observed portion. Since the intensity of the above-described drug fluorescence and autofluorescence is very weak, if the illuminance distribution of the excitation light is non-uniform and there is a portion where the excitation light is not sufficiently irradiated, unevenness is generated on the fluorescence image and appropriate. A fluorescence image cannot be acquired.

  Patent Document 1 proposes to average the light amount distribution by dimming light emitted from a lamp light source with a donut-shaped light shielding plate. However, in this method, the light attenuation rate by the light shielding plate is large. There is a problem that utilization efficiency of light emitted from the light source is reduced.

  In view of the above problems, an object of the present invention is to provide a light source device capable of irradiating light with a sufficient and uniform illuminance distribution onto an observed portion.

  The light source device of the present invention emits irradiation light that irradiates the observed portion, and guides the incident light while repeating side-surface reflection and emits it with respect to the optical axis of the light guide. Is disposed between the light source and the light guide and the incident end face of the light guide irradiation light. The irradiation light is incident and the irradiation light is directed toward the optical axis center of the light guide. And a gradient filter configured to reduce transmittance.

  Further, in the light source device of the present invention, a tilting filter having a transmittance distribution in which the transmittance of irradiation light monotonously decreases toward the center of the optical axis of the light guide can be used.

  Moreover, what has the transmittance | permeability distribution which the transmittance | permeability of irradiation light reduces linearly toward the optical axis center of a light guide can be used as an inclination filter.

  In addition, an optical system that makes the beam cross-sectional shape of the irradiation light elliptical can be provided.

  In addition, it is possible to provide a diffusion unit that diffuses light emitted from the emission end face of the light guide.

  A single-core optical fiber can be used as the light guide.

  A semiconductor light source can be used as the light source.

  A laser light source can be used as the semiconductor light source.

  According to the light source device of the present invention, the light source is arranged so that the optical axis of the irradiation light is incident with the optical axis of the light guide being inclined with respect to the optical axis of the light guide that is guided and emitted while repeating side reflection of the incident light. In addition, since an inclined filter configured to reduce the transmittance of the irradiation light toward the optical axis center of the light guide is provided between the light source and the incident end surface of the irradiation light of the light guide, sufficient and uniform Light with a proper illuminance distribution can be emitted from the light guide.

  That is, the irradiation light incident on the light guide described above is averaged in the light guide, and the concentric illumination distribution irradiation light having the angle component of the incident irradiation light is emitted from the light guide. In this case, since the irradiation light averaged with the high angle component is averaged over a wider azimuth angle than the irradiation light averaged with the low angle component, for example, it is emitted from a laser light source or a light emitting diode. When irradiation light with a large amount of illuminance distributed at the center is incident obliquely with respect to the optical axis of the light guide as in the present invention, the high angle component increases, so that a uniform illuminance distribution can be obtained. it can. At this time, a tilt filter is provided so that the transmittance of the irradiation light decreases toward the center of the optical axis of the light guide, and the irradiation light transmitted through the tilt filter is incident on the light guide at a relatively small incident angle. Accordingly, it is possible to suppress a decrease in illuminance due to the incident light incident on the light guide from an oblique direction, and it is possible to emit irradiation light having a sufficient and uniform illuminance distribution from the light guide.

  Then, by irradiating the portion to be observed with the irradiation light emitted from the light guide, it is possible to irradiate the portion to be observed with irradiation light having a sufficient and uniform illuminance distribution.

  In addition, regarding the irradiation light incident at a high angle with respect to the incident end face of the light guide, the expected size is reduced because the shape of the incident surface of the irradiation light of the light guide is an ellipse. Specifically, assuming that the area of the incident surface of the light guide irradiated light is Ω and the incident angle is θ, the expected size at the incident end surface of the light guide is represented by Ω cos θ. As the expected size decreases, the amount of incident irradiation light also decreases.

  Therefore, when an optical system that makes the beam cross-sectional shape of the irradiation light incident on the light guide an ellipse is provided, the amount of irradiation light can be concentrated within the expected size at the incident end face of the light guide. It is possible to avoid the above-described decrease in the amount of light.

  In addition, in the case where a diffusing portion for diffusing the irradiation light emitted from the emission end face of the light guide is provided, light with a more uniform illuminance distribution can be obtained. Further, by using such a diffusing section, it is possible to obtain uniform irradiation light in a wider range than the light receiving angle of the light guide. Note that the angular distribution of the irradiation light incident on the light guide may be set in consideration of the averaging in the diffusion unit.

Schematic configuration diagram of a rigid endoscope system using an embodiment of a light source device of the present invention Schematic configuration diagram of body cavity insertion part Schematic configuration diagram of the imaging unit The figure which shows the internal structure of the processor and light source device in the rigid endoscope system shown in FIG. The figure which shows an example of the transmittance | permeability distribution of the excitation light of an inclination filter with respect to the incident angle to the light guide of excitation light The figure which shows an example of the calculated value of the incident angle distribution of the excitation light which injects into a light guide The figure which shows an example of the calculated value of the emitted light distribution of the excitation light when the inclined filter is used and the calculated value of the emitted light distribution of the excited light when the inclined filter is not used The figure which shows an example of the calculated value of angle distribution of incident light when excitation light injects with the incident angle of 35 degrees about the horizontal direction with respect to the optical axis of a light guide, without using an inclination filter. The figure which shows an example of the calculated value of the illumination intensity distribution of the emitted light radiate | emitted from a light guide when excitation light injects with the incident angle of 35 degrees about the horizontal direction with respect to the optical axis of a light guide, without using an inclination filter. The figure which shows other embodiment of the light source device of this invention.

  Hereinafter, a rigid endoscope system using an embodiment of a light source device of the present invention will be described in detail with reference to the drawings. The rigid endoscope system of this embodiment is characterized by the configuration of the light source device. First, the configuration of the entire rigid endoscope system will be described. FIG. 1 is an external view showing a schematic configuration of a rigid endoscope system 1 of the present embodiment.

  As shown in FIG. 1, the rigid endoscope system 1 according to the present embodiment guides the normal light and excitation light emitted from the light source device 2 and the light source device 2 that emits white normal light and excitation light. A rigid mirror imaging apparatus that irradiates the observation unit and captures a normal image based on reflected light reflected from the observed portion by irradiation of normal light and a fluorescent image based on fluorescence emitted from the observed portion by irradiation of excitation light 10, a processor 3 that performs a predetermined process on the image signal captured by the rigid endoscope imaging device 10, and a monitor 4 that displays a normal image and a fluorescence image of the observed portion based on a display control signal generated by the processor 3. And.

  As shown in FIG. 1, the rigid endoscope imaging apparatus 10 includes a body cavity insertion unit 30 that is inserted into a body cavity, and an imaging unit 20 that captures a normal image and a fluorescence image of the observed portion guided by the body cavity insertion unit 30. And.

  Moreover, as shown in FIG. 2, the rigid-scope imaging device 10 has the body cavity insertion part 30 and the imaging unit 20 connected detachably. The body cavity insertion portion 30 includes a connection member 30a, an insertion member 30b, a cable connection portion 30c, an irradiation window 30d, and an imaging window 30e.

  The connection member 30a is provided at one end 30X of the body cavity insertion portion 30 (insertion member 30b) on the imaging unit 20 side. For example, the connection member 30a is fitted into an opening 20a formed in the imaging unit 20, thereby The body cavity insertion part 30 is detachably connected.

  The insertion member 30b is inserted into the body cavity when photographing inside the body cavity, and is formed of a hard material and has, for example, a cylindrical shape with a diameter of about 5 mm. Inside the body cavity insertion section 30, a normal image and a fluorescence image of the observed part incident from the imaging window 30e are formed, guided to one end 30X on the imaging unit 20 side of the body cavity insertion section 30, and one end thereof A relay lens 30f (see FIG. 4) that emits light from the portion 30X is provided. The normal image and the fluorescence image emitted from the relay lens 30 f are incident on the imaging unit 20.

  As shown in FIG. 2, a cable connection portion 30c is provided on the side surface of the insertion member 30b, and the light guide LG is mechanically connected to the cable connection portion 30c by a connector C. Thereby, the light source device 2 and the insertion member 30b are optically connected via the light guide LG.

  A connector 71 (see FIG. 4) is provided at the tip of the light guide LG, and the light guide LG is detachably connected to the light source device 2 via the connector 71. The light guide LG is composed of, for example, a bundled multimode optical fiber.

  In the body cavity insertion portion 30, a bundled multimode optical fiber 30g (see FIG. 4) that guides normal light and excitation light emitted from the light guide LG connected to the cable connection portion 30c. The multimode optical fiber 30g is provided to guide incident normal light and excitation light to the distal end portion 30Y of the insertion member 30b and irradiate the observed portion. The multimode optical fiber 30g provided in the insertion member 30b has its tip polished to form an irradiation window 30d.

  FIG. 3 is a diagram illustrating a schematic configuration of the imaging unit 20. The imaging unit 20 includes a first imaging system that captures the fluorescence image L4 of the observed part imaged by the relay lens 30f in the body cavity insertion part 30 and generates a fluorescence image signal of the observed part, and the body cavity insertion part And a second imaging system that generates a normal image signal by capturing a normal image L3 of the observed portion imaged by the relay lens 30f within 30. These imaging systems are divided into two optical axes orthogonal to each other by a dichroic prism 21 having a spectral characteristic that reflects the normal image L3 and transmits the fluorescent image L4.

  The first imaging system cuts light having a wavelength equal to or less than the wavelength of the excitation light reflected by the observed portion and transmitted through the dichroic prism 21 and an excitation light cut filter 22 that transmits fluorescent wavelength region illumination light, which will be described later, and a body cavity A first imaging optical system 23 that forms a fluorescent image L4 emitted from the insertion unit 30 and transmitted through the dichroic prism 21 and the excitation light cut filter 22, and a fluorescent image L4 imaged by the first imaging optical system 23 And a high-sensitivity image pickup device 24 for picking up images.

  The high-sensitivity imaging element 24 detects light in the wavelength band of the fluorescent image L4 with high sensitivity, converts it into a fluorescent image signal, and outputs it. As the high sensitivity image sensor 24, for example, a monochrome image sensor can be used.

  The second imaging system includes a second imaging optical system 25 that forms a normal image L3 emitted from the body cavity insertion unit 30 and reflected by the dichroic prism 21, and a normal image formed by the second imaging optical system 25. An image sensor 26 that captures the image L3 is provided.

  The image sensor 26 detects light in the wavelength band of the normal image, converts it into a normal image signal, and outputs it. On the image pickup surface of the image pickup element 26, color filters of three primary colors red (R), green (G) and blue (B), or cyan (C), magenta (M) and yellow (Y) are arranged in a Bayer array or a honeycomb. It is provided in an array.

  In addition, the imaging unit 20 includes an imaging control unit 27. The imaging control unit 27 performs CDS / AGC (correlated double sampling / automatic gain control) processing and A / A processing on the fluorescence image signal output from the high-sensitivity imaging device 24 and the normal image signal output from the imaging device 26. A D-conversion process is performed and output to the processor 3 via the cable 5 (see FIG. 1).

  As shown in FIG. 4, the processor 3 includes a normal image input controller 41, a fluorescence image input controller 42, an image processing unit 43, a memory 44, a video output unit 45, an operation unit 46, a TG (timing generator) 47, and a CPU 48. ing.

  The normal image input controller 41 and the fluorescence image input controller 42 include a line buffer having a predetermined capacity, and the normal image input controller 41 receives a normal image signal for each frame output from the imaging control unit 27 of the imaging unit 20. The fluorescent image input controller 42 temporarily stores a fluorescent image signal. The normal image signal stored in the normal image input controller 41 and the fluorescent image signal stored in the fluorescent image input controller 42 are stored in the memory 44 via the bus.

  The image processing unit 43 receives the normal image signal and the fluorescence image signal for each frame read from the memory 44, performs predetermined image processing on these image signals, and outputs them to the bus.

  The video output unit 45 receives the normal image signal and the fluorescence image signal output from the image processing unit 43 via the bus, performs predetermined processing to generate a display control signal, and outputs the display control signal to the monitor 4. Output.

  The operation unit 46 receives input by the operator such as various operation instructions and control parameters. As will be described in detail later, in particular, in the present embodiment, a change in the exit angle of excitation light or normal light is accepted.

  The TG 47 outputs a drive pulse signal for driving the high-sensitivity image pickup device 24, the image pickup device 26 of the image pickup unit 20, and an LD driver 53 of the light source device 2 described later. The CPU 48 controls the entire apparatus.

  The processor 3 and the imaging unit 20 are connected via a cable 5 as shown in FIGS. 1 and 4. The cable 5 includes a signal wiring that propagates a normal image signal and a fluorescent image signal captured by the imaging unit 20, a control wiring that transmits a control signal output from the processor 3, and the like. A connector 5a and a connector 5b are provided at the tip of the cable 5. The cable 5 is detachably connected to the processor 3 via the connector 5a, and is detachably connected to the imaging unit 20 via the connector 5b. Is.

  As shown in FIG. 4, the light source device 2 emits a normal light (white light) L <b> 1 having a broadband wavelength of about 400 nm to 700 nm and a normal light L <b> 1 emitted from the visible light lamp 50. An aspherical lens 51 that emits substantially parallel light, a near-infrared laser light source 52 that emits excitation light that is near-infrared light of 750 nm to 790 nm, an LD driver 53 that drives the near-infrared laser light source 52, A condensing lens 54 that condenses the excitation light L2 emitted from the near-infrared laser light source 52 and makes the optical axis of the excitation light L2 tilt with respect to the optical axis of the light guide 60 described later, and condensing A tilt filter 55 installed between the lens 54 and the light guide 60 and configured to decrease the transmittance of the excitation light L2 toward the center of the optical axis of the light guide 60, and an excitation transmitted through the tilt filter 55. Light L2 is incident from the incident end face 60a, one light guide 60 that guides the incident excitation light L2 and exits from the exit end face 60b, and diffusion that diffuses the excitation light L2 emitted from the light guide 60 A dichroic mirror 62 that transmits the excitation light L2 emitted from the diffusing unit 61 and reflects the normal light L1 emitted from the aspherical lens 51 toward a condenser lens 63 described later, and a dichroic mirror 62. And a condensing lens 63 for condensing the normal light L1 reflected by the dichroic mirror 62 and making it incident on the light incident end face 70 of the light guide LG.

  As the visible light lamp 50, for example, a xenon lamp is used. In this embodiment, white light is used as the normal light L1 (visible light). However, the present invention is not limited to this, and other light may be used as long as it has a visible wavelength.

  In this embodiment, a near infrared laser light source is used as a light source that emits near infrared light as excitation light. However, the present invention is not limited to this, and a near infrared light emitting diode may be used. .

  The light guide 60 of this embodiment is a single-core optical fiber. Specifically, for example, an optical fiber having a core diameter of 200 μm and an NA of 0.36 can be used. However, the light guide is not limited to an optical fiber, and a light pipe that guides and emits light while repeating side reflection of incident light in the same manner as the optical fiber can be used. In addition, the light receiving angle of the light guide can be selected according to the required illumination range, and is not limited to an optical fiber having an NA of 0.36, but also an optical fiber having an NA of 0.48, 0.22, or 0.12. Can be used.

  Here, in this embodiment, the optical axis of the excitation light L2 emitted from the near-infrared laser light source 52 and condensed by the condenser lens 54 is 18 ° in the horizontal direction with respect to the optical axis of the light guide 60. It is assumed that the near-infrared laser light source 52 and the condenser lens 54 are arranged so as to have an angle of. Here, the horizontal incident angle described above is θx, the vertical incident angle θy, and the angle in the direction that coincides with the optical axis direction is 0 °. That is, it is assumed that the near-infrared laser light source 52 and the condenser lens 54 are arranged so that the optical axis of the excitation light L2 is θx = 18 °. In FIG. 4, in order to clearly show the incident angle θx = 18 ° of the excitation light with respect to the optical axis of the light guide 60, the horizontal direction is expressed as a vertical direction.

  In the present embodiment, the condensing lens 54 having a focal length of 6 mm is used to condense the excitation light L <b> 2 on the incident end surface 60 a of the light guide 60 at a double magnification. As shown in FIG. 4, the condenser lens 54 is disposed at a position of d1 = 18 mm in the direction of θx = 18 ° from the incident end face 60a of the light guide 60, and the near-infrared laser light source 52 is disposed from the condenser lens 54. It is arranged at a position of d2 = 9 mm in the direction of θx = 18 °.

Further, in the present embodiment, as shown in FIG. 4, the optical axis of the condenser lens 54 and the excitation light L2
However, the present invention is not limited to this, and the light of the excitation light L2 with respect to the optical axis of the light guide 60 is shifted by shifting the optical axis of the condenser lens 54 and the optical axis of the excitation light L2. You may make it inject by inclining an axis | shaft.

  Further, in the present embodiment, the excitation light L2 is imaged by one condenser lens 54, that is, the excitation light L2 is incident on the light guide 60 by one optical element having a positive power. The collimating lens or the like makes the parallel light by one optical element having a positive power, and then the excitation light L2 is made incident on the light guide 60 by the one optical element having a positive power such as a condenser lens. Good. Further, the excitation light L2 emitted from the near-infrared laser light source 52 may be directly incident on the light guide 60 via the inclined filter 55 without using an optical element such as a condenser lens.

  In the present embodiment, the condensing lens 54 having positive power is used as an optical element that makes the excitation light L2 incident on the incident end surface 60a of the light guide 60. However, as such a condensing lens, For example, a spherical lens, an aspherical lens, or a Fresnel lens can be used. Further, as other optical elements, a diffraction grating, a concave mirror, and a parabolic mirror can be used, and a condensing lens and these optical elements may be used in combination. The incident angle of the excitation light L <b> 2 to the light guide 60 can be set by the alignment between these optical elements and the near-infrared laser light source 52.

  As described above, the inclined filter 55 is configured so that the transmittance of the excitation light L2 decreases toward the center of the optical axis of the light guide 60, and the incidence of the excitation light L2 incident on the light guide 60 at a low angle. It is provided to increase the incident light amount of the excitation light L2 incident on the light guide 60 at a higher angle than the light amount. The inclined filter 55 transmits the excitation light L2 in the radial direction of the light guide 60 so that the transmittance of the excitation light L2 becomes lower as it approaches the optical axis of the light guide 60 and the illuminance distribution of the light emitted from the light guide 60 becomes uniform. The rate is configured to change.

  The transmittance gradient of the gradient filter 55 is a known gradient such as continuously changing the thickness of a metal film coated on a substrate such as glass or continuously changing the concentration of particles arranged on the substrate. The filter can be formed by using a manufacturing method.

  The inclined filter 55 is disposed at a position of d3 = 10 mm from the incident end face 60a of the light guide 60, and adjusts the light amount distribution of the incident excitation light L2 according to the incident angle θx of the excitation light L2 to the light guide 60. . FIG. 5 shows an example of the transmittance distribution of the excitation light L2 with respect to the incident angle θx of the excitation light L2 included in the inclined filter 55 in the present embodiment. That is, in the present embodiment, the transmittance is 0 for the excitation light L2 incident on the light guide 60 at an incident angle smaller than θx = −10 °, and incident at an angle larger than θx = 20 °. The transmittance is 1 for the excitation light L2 to be emitted, and increases linearly for the excitation light L2 incident at an angle of θx = −10 ° to 20 ° (in the center of the optical axis of the light guide 60). A gradient filter 55 having a transmittance distribution such that the transmittance is linearly decreased) is used. In the present embodiment, the transmittance distribution has a transmittance that increases linearly with respect to the excitation light L2 incident at an angle of θx = −10 ° to 20 °. However, the transmittance distribution is not necessarily linear. It is sufficient to use a filter whose transmittance increases monotonously (monotonically decreases toward the center of the optical axis of the light guide 60). For example, a gradient filter having a transmittance distribution having a transmittance that increases in a quadratic function is used. You may do it.

  Here, the distance between the inclined filter 55 and the incident end face 60a of the light guide 60 is d3, and the distance between the point on the inclined filter 55 and the optical axis of the light guide 60 is x. At this time, the position x through which the excitation light L2 having an incident angle of θx passes on the inclined filter 55 can be expressed as x = d3 tan θx. As described above, since the tilt filter 55 is disposed at a position of d3 = 10 mm from the incident end face 60a of the light guide 60, the position on the tilt filter 55 corresponding to the incident angle of θx = −10 ° is x. = 10 × tan (−10 °) ≈−1.76 mm, and the position on the inclined filter corresponding to the incident angle of θx = + 20 ° is x = 10 × tan (+ 20 °) ≈3.63 mm. The position of the gradient filter 55 is adjusted so that the transmittance of the excitation light L2 at the position x becomes the transmittance shown in FIG. It is assumed that the transmittance of the gradient filter 55 does not depend on θy.

  In the present embodiment, the inclined filter 55 is disposed between the incident end face 60a of the light guide 60 and the condenser lens 54. However, the incident angle dependency similar to the above is applied to the excitation light L2. You may make it arrange | position in another place, as long as it is obtained. For example, it may be disposed between the near-infrared laser light source 52 and the condensing lens 54, and when a collimating lens is provided between the near-infrared laser light source 52 and the condensing lens 54, the collimating lens And the condensing lens 54 may be arranged.

  FIG. 6 shows calculated values of the incident angle distribution of the excitation light L2 incident on the light guide 60 with the above-described configuration. A dotted circle in FIG. 5 is an acceptance angle of the light guide 60, and the excitation light L <b> 2 incident within the acceptance angle propagates through the light guide 60. At this time, the angle distribution of the excitation light L2 is averaged in the azimuth direction while propagating through the light guide 60, and emitted with an illuminance distribution that is symmetric about the optical axis. FIG. 7 shows the calculated value of the emitted light distribution of the excitation light L2 when the inclined filter is used as in the present embodiment and the calculated value of the emitted light distribution of the excited light L2 when the inclined filter is not used. It is. As shown in FIG. 7, when the inclined filter 55 is used, high uniformity can be obtained within an irradiation range of ± 20 °. 7 does not propagate due to the allowable NA limit of the light guide 60.

  In this embodiment, only one light guide 60 to which the excitation light L2 is incident is provided. However, the present invention is not limited to this, and the excitation light L2 that has passed through the inclined filter 55 is incident as described above. A plurality of light guides 60 may be provided. For example, a bundle optical fiber in which a plurality of optical fibers are bundled may be used.

  The diffusion unit 61 diffuses the excitation light L2 emitted from the emission end face 60b of the light guide 60 and emits the excitation light L2 having a substantially uniform illuminance distribution. As the diffusing unit 61, for example, frosted glass, a microlens array, a micro uneven structure, a fine particle dispersed film, or other optical elements having a diffusing action can be used.

  As described above, the dichroic mirror 62 reflects the normal light L1 and transmits the excitation light L2, and is disposed with an inclination of 45 ° with respect to the optical axis direction of the condenser lens 63.

  As described above, the condenser lens 63 receives the normal light L1 that has been made substantially parallel light by the aspheric lens 51, and condenses the normal light L1 on the light incident end face 70 of the light guide LG. In addition, the excitation light L2 emitted from the diffusing unit 61 is incident, and the excitation light L2 is collected and incident on the light incident end face 70 of the light guide LG.

  In the present embodiment, near-infrared light is used as the excitation light. However, the present invention is not limited to this, and other wavelengths narrower than normal light having a wide-band wavelength can be used. And excitation light is not limited to the light of the said wavelength range, It determines suitably by the kind of fluorescent pigment | dye, or the kind of biological tissue made to autofluoresce.

  Next, the operation of the rigid endoscope system of this embodiment will be described.

  First, the connector C of the light guide LG connected to the light source device 2 is connected to the cable connection portion 30c of the insertion member 30b of the body cavity insertion portion 30, and the connector 5b of the cable 5 connected to the processor 3 is connected to the imaging unit 20. Connected to.

  Next, after the light source device 2 is turned on, the user inserts the body cavity insertion part 30 into the body cavity, and the tip of the body cavity insertion part 30 is installed in the vicinity of the observed part.

  Then, the normal light L 1 is emitted from the visible light lamp 50 of the light source device 2, and the normal light L 1 is made substantially parallel light by the aspherical lens 51 and then reflected by the dichroic mirror 62 in a right angle direction to the condenser lens 63. Then, the light is collected by the condenser lens 63 and is incident on the light incident end face 70 of the light guide LG.

  On the other hand, the excitation light L 2 is emitted from the near-infrared laser light source 52 of the light source device 2, and the excitation light L 2 enters the condenser lens 54.

  Then, the excitation light L2 incident on the condenser lens 59 is incident on the inclined filter 55, and is adjusted to a light amount distribution according to the incident angle in the inclined filter 55. Then, the excitation light L <b> 2 that has passed through the inclined filter 55 is incident such that the optical axis of the excitation light L <b> 2 is inclined with respect to the optical axis of the light guide 60. The excitation light L2 incident on the light guide 60 is averaged and guided by the light guide 60, and then emitted from the emission end face 60b of the light guide 60. The excitation light L2 is diffused by the diffusion unit 61 and is dichroic. After passing through the mirror 62, the light enters the condenser lens 63. Then, the excitation light L2 incident on the condenser lens 63 is condensed by the condenser lens 63 and incident on the light incident end face 70 of the light guide LG.

  Next, the normal light L1 and the excitation light L2 incident on the light incident end face 70 of the light guide LG as described above are guided by the light guide LG and incident on the multimode optical fiber 30g in the body cavity insertion portion 30. The normal light L1 and the excitation light L2 incident from the end face and guided by the multimode optical fiber 30g are irradiated from the distal end of the body cavity insertion portion 30 toward the observed portion.

  And the normal image based on the reflected light reflected from the observed part by the irradiation of the normal light L1 as described above is picked up, and the fluorescent image based on the fluorescence emitted from the observed part by the irradiation of the excitation light L2 is obtained. Imaged. It should be noted that ICG is administered to the observed part in advance, and fluorescence emitted from the ICG is imaged.

  Specifically, when the normal image is captured, the normal image L3 based on the reflected light reflected from the observed portion by the irradiation of the normal light L1 is incident from the distal end portion 30Y of the insertion member 30b, and the inside of the insertion member 30b. Are guided by the relay lens 30 f and emitted toward the imaging unit 20.

  The normal image L3 incident on the imaging unit 20 is reflected by the dichroic prism 21 in the direction perpendicular to the imaging element 26, and is imaged on the imaging surface of the imaging element 26 by the second imaging optical system 25. 26 sequentially captures images at a predetermined frame rate.

  The normal image signals sequentially output from the image sensor 26 are subjected to CDS / AGC (correlated double sampling / automatic gain control) processing and A / D conversion processing in the imaging control unit 27, and then the processor via the cable 5. 3 are sequentially output.

  The normal image signal input to the processor 3 is temporarily stored in the normal image input controller 41 and then stored in the memory 44. Then, the normal image signal for each frame read from the memory 44 is subjected to gradation correction processing and sharpness correction processing in the image processing unit 43 and then sequentially output to the video output unit 45.

  Then, the video output unit 45 performs predetermined processing on the input normal image signal to generate a display control signal, and sequentially outputs the display control signal for each frame to the monitor 4. The monitor 4 displays a normal image based on the input display control signal.

  On the other hand, when capturing a fluorescent image, a fluorescent image L4 based on the fluorescence emitted from the observed portion by irradiation with the excitation light L2 is incident from the distal end portion 30Y of the insertion member 30b, and the relay lens 30f in the insertion member 30b. Is guided toward the image pickup unit 20.

  The fluorescent image L4 incident on the imaging unit 20 passes through the dichroic prism 21 and the excitation light cut filter 22, and is then imaged on the imaging surface of the high-sensitivity imaging element 24 by the first imaging optical system 23, and has high sensitivity. Images are taken at a predetermined frame rate by the image sensor 24.

  The fluorescent image signals sequentially output from the high-sensitivity image sensor 24 are subjected to CDS / AGC (correlated double sampling / automatic gain control) processing and A / D conversion processing in the imaging control unit 27, and then passed through the cable 5. Are sequentially output to the processor 3.

  The fluorescence image signal input to the processor 3 is temporarily stored in the fluorescence image input controller 42 and then stored in the memory 44. Then, the fluorescence image signal for each frame read from the memory 44 is subjected to predetermined image processing in the image processing unit 43 and then sequentially output to the video output unit 45.

  Then, the video output unit 45 performs a predetermined process on the input fluorescent image signal to generate a display control signal, and sequentially outputs the display control signal for each frame to the monitor 4. The monitor 4 displays a fluorescent image based on the input display control signal.

  According to the rigid endoscope system of the above-described embodiment, the optical axis of the excitation light L2 is inclined and incident with respect to the optical axis of the light guide 60 that is guided and emitted while repeating side reflection of the incident light. Since the near-infrared laser light source 51 is arranged, it is possible to increase the excitation light that is averaged with a high angle component in the light guide 60, thereby obtaining the excitation light having a uniform illuminance distribution. be able to. At this time, an inclined filter 55 is provided so that the transmittance of the excitation light L2 decreases toward the center of the optical axis of the light guide 60. The excitation light L2 transmitted through the inclined filter 55 is relatively small to the light guide 60. Since the incident light is incident at an incident angle, it is possible to suppress a decrease in illuminance due to the incidence of the excitation light L2 on the light guide 60 from an oblique direction. Can be emitted.

  Then, by irradiating the observed part with the excitation light L2 emitted from the emission end face 60b of the light guide 60, it is possible to irradiate the observed part with light having sufficient intensity and uniform illuminance distribution.

  Here, as a comparative example to the above-described embodiment, when the excitation light L2 is incident at an incident angle of 35 ° in the horizontal direction with respect to the optical axis of the light guide 60 without using the inclined filter as in the above-described embodiment. FIG. 8 shows the calculated value of the angular distribution of the incident light, and FIG. 9 shows the calculated value of the illuminance distribution of the emitted light emitted from the light guide 60. The dotted circle in FIG. 8 also shows the acceptance angle of the light guide 60. In this case, a flat illuminance distribution as shown in FIG. 9 can be obtained by entering at a higher angle than in the above embodiment, but the illuminance decreases due to the incidence of the excitation light L2 on the light guide 60 from an oblique direction. Therefore, only about 70% of illuminance can be obtained as compared with the case of using the gradient filter as in the above embodiment.

  In the light source device 2 of the rigid endoscope system according to the above embodiment, the excitation light L2 is incident on the optical axis of the light guide 60 from an oblique direction. When the excitation light is incident on the incident end surface 60a from an oblique direction, the incident direction of the excitation light with respect to the incident end surface 60a is not vertical, but is inclined from the vertical direction, so that the shape of the excitation light incident surface is an ellipse. As a result, the expected size is reduced and the amount of light is lost.

  Therefore, for example, the beam cross-sectional shape of the excitation light L2 so that the beam cross-sectional shape of the excitation light L2 incident from the oblique direction with respect to the optical axis of the light guide 60 is the same as the shape of the incident surface of the excitation light. An optical system having an ellipse may be provided.

  As a configuration using such an optical system, for example, as shown in FIG. 10, the excitation light L2 emitted from the near-infrared laser light source 52 is collimated by a collimating lens 56 having a focal length d4 = 9 mm, and then anamorphic. It is possible to adopt a configuration in which the beam cross-sectional shape is made into an ellipse by the Fick prism pair 57 and made incident on the condensing lens 54 having a focal length d1 = 18 mm. The material of the light guide 60, the incident angle to the light guide 60, the arrangement of the inclined filter 55, the transmittance distribution, and the like are the same as in the above embodiment. Further, the distance d3 between the incident end face 60a of the light guide 60 and the inclined filter 55 is also d3 = 10 mm as in the above embodiment. Even in such a configuration, similarly to the above-described embodiment, the excitation light L2 incident on the light guide 60 is averaged in the light guide 60, and emitted light having a uniform illuminance distribution can be obtained. Since the optical axis of the excitation light L2 incident on the light guide 60 is inclined by θx = 18 ° with respect to the optical axis of the light guide 60, the expected size of the incident end face 60a of the light guide 60 is 95 of the original size. However, by making the beam cross-sectional shape of the excitation light L2 elliptical by the optical system, it is possible to reduce the loss of light quantity due to the reduction in the expected size of the incident end face 60a.

  As the optical system, for example, an anamorphic prism as shown in FIG. 10 can be used. However, the present invention is not limited to this, and other known optical systems can be used. For example, a wedge plate or a cylindrical lens can also be used.

  Thus, by providing the optical system that makes the beam cross-sectional shape of the excitation light elliptical, it is possible to prevent the above-described loss of light amount.

  In the rigid endoscope system of the above embodiment, the light guide 60 to which the excitation light L2 is incident is provided in the light source device. However, for example, the light guide LG connected to the body cavity insertion unit 30 is a single-core light. When using a fiber or the like, it is not necessary to provide the light guide 60 in the light source device, and the excitation light L2 collected by the condenser lens 54 is directly incident on the light guide LG through the inclined filter 55. That's fine.

  In the rigid endoscope system of the above-described embodiment, the fluorescent image is captured by the first imaging system. However, the present invention is not limited to this, and the light absorption characteristics of the observed part due to the irradiation of the special light to the observed part are not limited. You may make it image the image based on.

  Moreover, although the said embodiment applies the light source device of this invention to a rigid endoscope system, you may apply not only to this but a flexible endoscope system, for example.

DESCRIPTION OF SYMBOLS 1 Rigid endoscope system 2 Light source device 3 Processor 4 Monitor 5 Cable 10 Rigid endoscope imaging device 20 Imaging unit 24 High sensitivity imaging device 26 Imaging device 30 Body cavity insertion part 30f Relay lens 30g Multimode optical fiber 50 Visible light lamp 51 Aspherical lens 52 Near-infrared laser light source 54 Condensing lens 55 Tilting filter 59 Condensing lens 60 Light guide 60a Incident end face 60b Outgoing end face 61 Diffusion part 62 Dichroic mirror 63 Condensing lens

Claims (7)

The irradiated light is emitted to the observed part, and the incident light is incident with the optical axis of the irradiated light being inclined with respect to the optical axis of the light guide that guides and emits the incident light while repeating side reflection. A light source arranged so that
Transmission between the light source and the incident end face of the light guide of the light guide, where the light is incident and the transmittance of the light is monotonously decreased toward the optical axis center of the light guide A light source device comprising a gradient filter having a rate distribution . The inclined filter, the light source apparatus according to claim 1, wherein a transmittance of the illumination light and has a transmittance distribution that decreases linearly toward the optical axis of the light guide. 3. The light source device according to claim 1, further comprising an optical system that makes an elliptical cross-sectional shape of the irradiation light. The light source device according to any one of claims 1 to 3 , further comprising a diffusing unit that diffuses light emitted from an emission end face of the light guide. The light guide, a light source device of claim 1, wherein 4 describes that an optical fiber of a single core. Wherein the light source, the light source apparatus according to claim 1 to 5 any one of claims, characterized in that the semiconductor light source. The semiconductor light source is a light source apparatus according to claim 1 to 6 or 1, wherein said is a laser light source.