JP2013090706A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device for emitting light to irradiate an observed portion, in which light with enough strength and uniform illumination distribution is irradiated to the observed portion.SOLUTION: The light source device makes lights emitted from a plurality of light sources 52, 53, and 54 enter one light guide 60 which guides and emits the incident light while repeating side reflection of the incident light, and makes each light enter at different angles from each other to an optical axis of the one light guide.

Description

  The present invention relates to a light source device including a plurality of light sources that emit light to be irradiated on an observed portion.

  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.

  Here, in the endoscope system for acquiring a fluorescence image as described above, the intensity of drug fluorescence or autofluorescence emitted from the observed part is very weak, so The illuminance of excitation light such as infrared light is preferably large.

  On the other hand, it has been proposed to use a semiconductor light source such as a laser light source or a light emitting diode as a light source for emitting excitation light such as near infrared light. However, if only one of these light sources is used, sufficient excitation light can be obtained. Unable to get illuminance. Thus, for example, Patent Document 1 proposes to use a plurality of light sources.

JP 2002-65603 A

  However, in general, when light emitted from a laser light source or a light emitting diode is incident on a light guide such as an optical fiber by a normal method, an illuminance distribution is obtained in which the illuminance at the center portion is large and the illuminance is small at the surrounding portion. Therefore, it is impossible to irradiate the observed part with excitation light having a uniform illuminance distribution. As described above, since the fluorescence intensity emitted from the observed part by the irradiation of the excitation light is 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 occurs and an appropriate fluorescent image cannot be acquired.

  Patent Document 1 discloses that light emitted from a plurality of light sources is incident on a light guide, but there is no suggestion of any method for making the illuminance distribution of the light irradiated to the observed portion uniform. It has not been.

  In view of the above-described problems, an object of the present invention is to provide a light source device that can irradiate a portion to be observed with light having sufficient intensity and uniform illuminance distribution.

  The light source device of the present invention has a plurality of light sources that emit light emitted to the observed portion, and the plurality of light sources guides and emits light while repeating side reflection of the incident light. The light emitted from each light source is incident on the guide, and the light is incident at different angles with respect to the optical axis of one light guide.

  In the light source device of the present invention, the second angle greater than the angle of 1 with respect to the optical axis of the light guide than the amount of light incident at the first angle with respect to the optical axis of the light guide. The amount of incident light can be increased.

  In addition, the number of light sources that cause light to enter the light guide at the second angle can be made larger than the number of light sources that cause light to enter the light guide at the first angle.

  Further, the intensity of the light emitted from the light source that causes the light guide to enter the light guide at the second angle can be made larger than the intensity of the light emitted from the light source that causes the light guide to enter the light guide at the first angle. .

  Further, the spread angle of light incident on the light guide at the second angle can be made smaller than the spread angle of light incident on the light guide at the first angle.

  A plurality of light sources can be arranged so that the incident angles formed by the optical axes of the light emitted from the respective light sources and the optical axis of the light guide are the same.

  Also, an optical system is provided that makes the beam cross-sectional shape of light incident from a plurality of light sources and incident on the light guide at an angle greater than 0 ° with respect to the optical axis of the light guide an ellipse. Can do.

  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, each light emitted from a plurality of light sources is incident on one light guide that is guided and emitted while repeating side reflection of the incident light, and the light guide. Since each light is incident at different angles with respect to the optical axis, each light incident on the light guide is averaged within the light guide, and is concentric with the angle component of the incident light. Light having an illuminance distribution is emitted from the light guide. As a result, a plurality of concentric illuminance distributions can be added, so that light with a substantially uniform illuminance distribution can be obtained at the exit end face of the light guide.

  Therefore, by irradiating the observed part with the light emitted from the exit end face of the light guide, it is possible to irradiate the observed part with light having sufficient intensity and uniform illuminance distribution.

  Further, among the light incident on the light guide, the light averaged with the high angle component is averaged over a wider azimuth angle than the light averaged with the low angle component. Therefore, the amount of light incident at a second angle greater than the angle of 1 with respect to the optical axis of the light guide is greater than the amount of light incident at the first angle with respect to the optical axis of the light guide. In the case of increasing the value, light having a more uniform angle component can be obtained.

  Further, when the spread angle of the light incident on the light guide at the second angle is made smaller than the spread angle of the light incident on the light guide at the first angle, the end of the illuminance distribution It is possible to obtain light having an illuminance distribution that sharply attenuates the amount of light at the portion. Light incident at an angle greater than the light guide's acceptance angle is lost, so using light with an illuminance distribution that sharply attenuates the amount of light at the end of the illuminance distribution improves the efficiency of using light that contributes to illumination. can do.

  In addition, when the light itself incident on the light guide has a certain spread angle, the light source is adjusted so that the incident angle formed by the optical axis of the light emitted from each light source and the optical axis of the light guide is the same. Even if they are arranged, the decrease in illuminance due to averaging is small at low angles, and the decrease in illuminance due to averaging is large at high angles, so that light having a uniform illuminance distribution can be obtained.

  In addition, for 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 light incident face of the light guide is an ellipse. Specifically, assuming that the area of the light incident surface of the light guide 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 light also decreases.

  Therefore, an optical system is provided that makes the beam cross-sectional shape of light incident from a plurality of light sources and incident on the light guide at an angle greater than 0 ° with respect to the optical axis of the light guide elliptical. In this case, the amount of light can be concentrated within the expected size on the incident end face of the light guide, so that the above-described reduction in the amount of light can be avoided.

  In addition, when a diffusing portion for diffusing light emitted from the light emitting end face of the light guide is provided, light with a more uniform illuminance distribution can be obtained. Further, by using such a diffusing portion, uniform illumination light in a wider range than the light receiving angle of the light guide can be obtained. Note that the angle distribution of the 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 angle distribution of excitation light L2_1-L2_3 in the incident end surface of a light guide The figure which shows an example of the illuminance distribution graph (dotted line) of the excitation light in the output end surface of a light guide, and the illuminance distribution graph (solid line) of the excitation light radiate | emitted from a diffusion part The figure which shows the illumination intensity distribution of the excitation light in the output end surface of a light guide The figure which shows the other example of angle distribution of excitation light L2_1-L2_3 in the incident end surface of a light guide The figure which shows arrangement | positioning of the near-infrared laser light source for implement | achieving the angle distribution of excitation light L2_1-L2_3 shown in FIG. The figure which shows other embodiment of the light source device of this invention. The figure which shows angle distribution of excitation light L2_1-L2_3 in the incident end surface of the light guide of the light source device shown in FIG. The figure which shows other embodiment of the light source device of this invention. The figure for demonstrating the example which makes the divergence angle of the excitation light which injects from the angle of +/- 20 degrees smaller than the divergence angle of the excitation light which injects from the angle of +10 degrees

  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 imaging device 24 for imaging the image.

  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 55 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 aspheric lens 51 that emits substantially parallel light, first to third near-infrared laser light sources 52, 53, and 54 that emit excitation light that is near-infrared light of 750 nm to 790 nm, and first to first The LD driver 55 that drives the three near-infrared laser light sources 52, 53, and 54, and the excitation lights L2_1 to L2_3 emitted from the first to third near-infrared laser light sources 52, 53, and 54, respectively, are substantially parallel light. The first to third collimating lenses 56, 57, and 58 and the excitation light L2_1 to L2_3 emitted from the first to third collimating lenses 56, 57, and 58 are condensed to a light guide 60 that will be described later. Incident end face 6 A condensing lens 59 that is incident on 0a at different angles, a single light guide 60 that guides excitation light L2_1 to L2_3 that has been collected and incident by the condensing lens 59 and exits from the exit end face 60b, A diffusion unit 61 that diffuses the excitation lights L2_1 to L2_3 emitted from the light guide 60, and a collection unit that transmits the excitation light L2 emitted from the diffusion unit 61 and the normal light L1 emitted from the aspherical lens 51, which will be described later. The dichroic mirror 62 reflecting toward the optical lens 63, the excitation light L2 transmitted through the dichroic mirror 62, and the normal light L1 reflected by the dichroic mirror 62 are collected and incident on the light incident end face 70 of the light guide LG. And a condenser lens 63.

  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 600 μm and NA of 0.48 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 0.48, but also an optical fiber having an NA of 0.36, 0.22, or 0.12. Can be used.

  The excitation lights L2_1 to L2_3 emitted from the first to third near-infrared laser light sources 52, 53, and 54 are incident from different incident positions of the condenser lens 59 and are collected by the condenser lens 59. The excitation lights L2_1 to L2_3 are incident on the optical axis of the light guide 60 at an angle different from each other.

  Here, in the present embodiment, the first and third near-infrared laser light sources 52, so that the excitation light L <b> 2 </ b> _ <b> 1 and the excitation light L <b> 2 </ b> _ <b> 3 are incident at an angle of 20 ° with respect to the optical axis of the light guide 60. 54 is arranged, and the second near-infrared laser light source 53 is arranged so that the excitation light L2_2 is incident at an angle of 10 ° with respect to the optical axis of the light guide 60. In other words, the first and third near-infrared laser light sources 52 and 54 are arranged at positions farther from the optical axis of the condenser lens 59 than the second near-infrared laser light source 53.

  And although the excitation light L2_1-L2_3 condensed by the condensing lens 59 injects into the entrance end surface 60a of the light guide 60 at mutually different angles, as shown in FIG. 5, the excitation light L2_1 and the excitation light L2_3 However, the light is incident from a position farther from the center position of the incident end face 60a than the excitation light L2_2.

  The excitation lights L2_1 to L2_3 incident from the incident end face 60a of the light guide 60 as described above are averaged and guided in the light guide 60 and emitted from the emission end face 60b. The intensity distribution is shown in FIG. In addition, the graph shown with a dotted line in FIG. 6 shows the intensity distribution of the excitation light L2_1 to L2_3 emitted from the emission end face 60b of the light guide 60. Further, the horizontal axis shown in FIG. 6 indicates the emission angles of the excitation lights L2_1 to L2_3 emitted from the emission end face 60b of the light guide 60.

  As shown in FIG. 6, the excitation light L2_1 and the excitation light L2_3 are emitted from the emission end face 60b of the light guide 60 at an emission angle of ± 20 °, and the excitation light L2_2 is emitted at an emission angle of ± 10 °. Become. As a result, concentric excitation lights L2_1 to L2_3 as shown in FIG. 7 are emitted from the emission end face 60b of the light guide 60. The smaller circular ring-shaped emitted light shown in FIG. 7 is the excitation light L2_2, and the larger circular ring-shaped emitted light is the excitation light L2_1 and the excitation light L2_3.

  Note that the illuminance of light emitted from the emission end face 60b of the light guide 60 becomes smaller as the incident angle (= emission angle) of the light increases, but in this embodiment, the incident angle (= emission angle). Since the number of near-infrared laser light sources that emit excitation light having a larger incident light is set to be larger than the number of near-infrared laser light sources that emit excitation light having a smaller incident angle (= emission angle), the light The illuminance of the excitation light L2_1 and the excitation light L2_3 emitted at the emission angle of ± 20 ° from the emission end face 60b of the guide 60 and the illuminance of the excitation light L2_2 emitted at the emission angle of ± 10 ° are substantially the same. Can do. As a method for making the illuminance distribution uniform, in addition to the method of increasing the number of near-infrared laser light sources as described above, near-infrared light that emits excitation light having a larger incident angle (= emission angle) is emitted. You may make it make the intensity | strength of the excitation light of a laser light source larger than the intensity | strength of the excitation light of the near-infrared laser light source which radiate | emits excitation light with a smaller incident angle (= emission angle). Further, the illuminance distribution may be made uniform by adjusting both the number of near-infrared laser light sources and the intensity of excitation light emitted from each near-infrared laser light source.

  Further, in the present embodiment, only one light guide 60 on which the excitation lights L2_1 to L2_3 collected by the condenser lens 59 are incident is provided. However, the present invention is not limited to this. A plurality of light guides 60 that allow a plurality of excitation lights to enter from an angle may be provided. For example, a bundle optical fiber in which a plurality of optical fibers into which a plurality of excitation lights are incident from different angles may be used.

  In the present embodiment, a condensing lens having a positive power is used as an optical element that causes the excitation lights L2_1 to L2_3 to enter 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 angles of the excitation lights L2_1 to L2_3 to the light guide 60 can be set by alignment of these optical elements with the first to third near-infrared laser light sources 52, 53, and 54.

  The diffusing section 61 diffuses the concentric excitation lights L2_1 to L2_3 emitted from the emission end face 60b of the light guide 60 and emits the excitation light L2 having a substantially uniform illuminance distribution. A graph indicated by a solid line in FIG. 6 shows the intensity distribution of the excitation light L2 emitted from the diffusing unit 61. 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, excitation lights L2_1 to L2_3 are emitted from the first to third near-infrared laser light sources 52, 53, and 54 of the light source device 2, and the excitation lights L2_1 to L2_3 are transmitted through the collimator lenses 56, 57, and 58, respectively. Thereafter, the light is incident from different incident positions of the condenser lenses 59.

  The excitation lights L2_1 to L2_3 incident on the condenser lens 59 are incident on the incident end surface 60a of the light guide 60 from different angles. The excitation lights L2_1 to L2_3 incident on the light guide 60 are averaged and guided by the light guide 60, and then emitted concentrically from the emission end face 60b of the light guide 60, and the concentric excitation lights L2_1 to L2_1. L2_3 is diffused by the diffusing unit 61, passes through the dichroic mirror 62, and then 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 a predetermined process 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 embodiment, each of the excitation lights L2_1 to L2_3 emitted from the plurality of near-infrared laser light sources 52, 53, and 54 is incident on one light guide 60, and the light guide thereof. Since the excitation lights L2_1 to L2_3 are incident at different angles with respect to the 60 optical axes, the excitation lights L2_1 to L2_3 incident on the light guide 60 are averaged in the light guide 60 and incident. The concentric illuminance distribution excitation light having the angle component of the excitation light emitted from the light guide 60 is emitted. As a result, a plurality of concentric illuminance distributions can be added, so that light with a substantially uniform illuminance distribution can be obtained at the emission end face 60 b of the light guide 60.

  Accordingly, by irradiating the observed part with the excitation light L2 emitted from the emission end face 60b of the light guide 60, the observed part can be irradiated with light having sufficient intensity and uniform illuminance distribution.

  Further, in the light source device 2 of the rigid endoscope system of the above embodiment, as shown in FIG. 5, the excitation light L2_2 having an angle of 10 ° is made incident in the upper semicircle of the incident end face 60a of the light guide 60. The excitation light L2_1 and the excitation light L2_3 having an angle of 20 ° are incident on the lower semicircle of the incident end face 60a of the light guide 60. However, the present invention is not limited to this, for example, as shown in FIG. All the excitation lights L2_1 to L2_3 may be incident on the upper semicircle of the incident end face 60a of the light guide 60.

  Specifically, as shown in FIG. 9, one of the set of the first near-infrared laser light source 52 and the collimating lens 56 and the set of the third near-infrared laser light source 54 and the collimating lens 58 are used. What is necessary is just to make it arrange | position close to the other group side. In FIG. 9, the set of the first near-infrared laser light source 52 and the collimating lens 56 and the set of the second near-infrared laser light source 54 and the collimating lens 58 are overlapped for easy understanding of the drawing. However, it is assumed that they are actually shifted slightly.

  As described above, the first near-infrared laser light source 52 and the collimating lens 56 and the third near-infrared laser light source 54 and the collimating lens 58 are disposed close to each other, thereby allowing the first to third. The near-infrared laser light source can be compactly arranged, and the size of the condensing lens 85 can be reduced, so that the size of the entire light source device can be reduced.

  Further, in the light source device 2 of the rigid endoscope system of the above embodiment, the excitation light is incident from the angle of + 10 ° and the angle of ± 20 ° with respect to the optical axis of the light guide 60. However, the present invention is not limited to this. Instead, for example, the excitation light may be incident from an angle of + 10 ° and an angle of −10 ° with respect to the optical axis of the light guide 60. That is, the excitation light may be incident so that the angle formed by the optical axis of the light guide 60 and the optical axis of each excitation light is the same.

  Specifically, for example, as shown in FIG. 10, a set of the first near infrared laser light source 80 and the collimating lens 82 and a set of the second near infrared laser light source 81 and the collimating lens 83 are combined. The excitation light L2_1 and the excitation light L2_2, which are provided symmetrically with respect to the optical axis of the light guide 60 and are respectively emitted from these sets, enter the condenser lens 84, and the incident end face 60a of the light guide 60 is incident on the condenser lens 84. You may make it inject into.

  As described above, when the excitation light L2_1 and the excitation light L2_2 are incident at an angle of + 10 ° and −10 ° with respect to the optical axis of the light guide 60, the emission end face 60b of the light guide 60 is incident. The circular ring-shaped excitation light L2_1 and excitation light L2_2 having the same radius are emitted from the center position of the emission end face 60b. Therefore, in order to make the illuminance distribution of the excitation light emitted from the emission end face 60b of the light guide 60 substantially uniform, for example, by increasing the focal length of the collimating lenses 82 and 83, as shown in FIG. The divergence angles of the excitation light L2_1 and the excitation light L2_2 incident on the incident end face 60a may be increased. In this way, the spreading angle of the excitation light L2_1 and the excitation light L2_2 is increased so that the excitation light is also incident near the center position of the incident end surface 60a of the light guide 60, thereby providing the diffusion unit 61 as in the above embodiment. The illuminance distribution of the excitation light emitted from the emission end face 60b of the light guide 60 can be made uniform.

  In the light source device 2 of the rigid endoscope system of the above embodiment, the excitation lights L2_1 and L2_3 are incident on the incident end face 60a of the light guide 60 from an angle of ± 20 °. When the excitation light is incident on the incident end face 60a from a direction inclined with respect to the optical axis 60, the incident direction of the excitation light with respect to the incident end face 60a is not vertical but inclined from the vertical direction. The shape of the surface becomes an ellipse, the expected size is reduced, and the amount of light is lost.

  Therefore, for example, as shown in FIG. 12, the beam cross-sectional shape of the excitation light L2_1 and L2_3 incident at an angle of ± 20 ° with respect to the incident end surface 60a of the light guide 60 and the shape of the excitation light incident surface are Optical systems 90 and 91 may be provided so that the beam cross-sectional shapes of the excitation light L2_1 and L2_3 are ellipses so as to be the same. As such optical systems 90 and 91, for example, an anamorphic prism as shown in FIG. 12 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 example shown in FIG. 12, the beam cross-sectional shape of the excitation light incident from an angle of ± 20 ° is made elliptical, but the beam cross-sectional shape of the excitation light incident from an angle of + 10 ° is also elliptical. You may make it. That is, with respect to the case of excitation light incident at an angle larger than 0 ° with respect to the optical axis of the light guide 60, the loss of the light amount can be reduced by providing an optical system that makes the beam cross-sectional shape elliptical, not limited to that angle. The effect of preventing can be acquired.

  Further, in the light source device 2 of the rigid endoscope system of the above embodiment, the spread angle of the excitation lights L2_1 to L2_3 incident on the light guide 60 is not particularly mentioned, but an angle of + 10 ° as shown in FIG. It is desirable that the divergence angle of the excitation light incident from an angle of ± 20 ° is smaller than the divergence angle of the excitation light incident from. By setting the divergence angle in this way, the illuminance distribution of the excitation light L2 emitted from the emission end face 60b of the light guide 60 can be such that the amount of light is sharply attenuated at the end of the illuminance distribution. . Since the excitation light incident at an angle larger than the light receiving angle of the light guide 60 is lost, as described above, the illuminance distribution in which the amount of light sharply attenuates at the end of the illuminance distribution makes it possible to contribute to the illumination. Light utilization efficiency can be increased. As described above, as a method of providing a difference in the spread angles of the excitation lights L2_1 to L2_3, the power of the optical element used for condensing each of the excitation lights L2_1 to L2_3 is changed, and the magnification at the time of collection is changed. Alternatively, another light source having a different divergence angle may be used.

  Further, in the light source device 2 of the rigid endoscope system of the above-described embodiment, the excitation lights L2_1 to L2_3 are made incident on the single positive power condenser lens 59 from different positions by the excitation light L2_1 to L2_3. The light guides 60 are incident from different angles with respect to the optical axis of the light guide 60. However, the present invention is not limited to this, and the first to third near-infrared laser light sources are not condensed by the condenser lens 59 or the like. The excitation light L2_1 to L2_3 may be incident on the optical axis of the light guide 60 from different angles by causing the emitted excitation light L2_1 to L2_3 to directly enter the incident end surface 60a of the light guide 60. .

  In the rigid endoscope system of the above embodiment, the light guide 60 to which the excitation lights L2_1 to L2_3 are 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. When the optical fiber or the like is used, it is not necessary to provide the light guide 60 in the light source device, and the excitation lights L2_1 to L2_3 collected by the condenser lens 59 may be directly incident on the light guide LG. .

  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 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 1st Near-infrared laser light source 53 second near-infrared laser light source 54 third near-infrared laser light source 56, 57, 58 collimating lens 59 condensing lens 60 light guide 61 diffusing section 62 dichroic mirror 63 condensing lens 80 first 1 near-infrared laser light source 81 2nd near-infrared laser light source 82, 83 collimating lens 84 condensing lens 85 condensing lens

Claims (11)

It has a plurality of light sources that emit light that irradiates the observed part,
The plurality of light sources make light emitted from each of the light sources incident on one light guide that is guided and emitted while repeating side-surface reflection of incident light. A light source device, wherein the light beams are incident at different angles with respect to the optical axis.   The amount of light incident at a second angle greater than the first angle with respect to the optical axis of the light guide than the amount of light incident at a first angle with respect to the optical axis of the light guide. The light source device according to claim 1, wherein the light source device is larger.   3. The number of light sources that cause light to enter the light guide at the second angle is greater than the number of light sources that cause light to enter the light guide at the first angle. The light source device described.   The intensity of light emitted from the light source that causes light to enter the light guide at the second angle is greater than the intensity of light emitted from the light source that causes light to enter the light guide at the first angle. The light source device according to claim 2.   5. The spread angle of light incident on the light guide at the second angle is smaller than the spread angle of light incident on the light guide at the first angle. The light source device according to claim 1.   5. The plurality of light sources are arranged such that the incident angles formed by the optical axes of the light emitted from the light sources and the optical axis of the light guide are the same. The light source device according to claim 1.   An optical system that makes the beam cross-sectional shape of light incident from the light sources incident on the light guide at an angle greater than 0 ° with respect to the optical axis of the light guide elliptical The light source device according to claim 1, wherein   8. The light source device according to claim 1, further comprising a diffusion unit that diffuses light emitted from an emission end face of the light guide. 9.   9. The light source device according to claim 1, wherein the light guide is a single-core optical fiber.   The light source device according to claim 1, wherein the light source is a semiconductor light source.   The light source device according to claim 1, wherein the semiconductor light source is a laser light source.

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