JP6359998B2 - Endoscope - Google Patents

Description

  The present invention relates to an endoscope.

  An endoscope apparatus that can realize switching of observation light without causing an increase in the size of the apparatus is known (see, for example, Patent Document 1). In the endoscope apparatus of Patent Document 1, a laser diode that emits light of a specific wavelength is provided as a light source, and an adapter is detachably provided at the distal end of an endoscope main body that is an emission end of laser light. This adapter is provided with a phosphor that emits light of another wavelength using light from a light source as excitation light. In the state where the adapter is not attached, the light of the light source of a specific wavelength is irradiated to the endoscope object as it is, and in the state where the adapter is attached, the light converted to another wavelength by the phosphor is applied to the endoscope object. Irradiated.

  Further, Patent Document 1 discloses an endoscope apparatus using a rotatable rotating member for an observation light switching structure. The endoscope apparatus of Patent Document 1 is provided with a rotating member that is rotatable in a direction intersecting the optical path of the light source, and the rotating member is provided with a window on which a phosphor is attached and a window on which the phosphor is not attached. ing. In this case, the observation light can be easily switched by switching the window by rotating the rotating member. In other words, according to the endoscope apparatus of Patent Document 1, it is possible to switch between light of a specific wavelength and light of other wavelengths only by an intervening operation of the phosphor by the switching structure. The observation light can be easily switched without increasing the size.

JP 2005-323738 A

  However, in the endoscope apparatus of Patent Document 1, when switching between light of a specific wavelength and light of other wavelengths, the adapter of the switching structure provided at the distal end of the endoscope body is detached and replaced, It is necessary to switch the window by rotating the rotating member. For this reason, for example, during the treatment, the wavelength of the illumination light that is the observation light (that is, the color of the illumination light) cannot be changed. In order to change the color of the illumination light, there is a disadvantage that the treatment must be interrupted. Moreover, the illumination light obtained by the switching structure with an adapter or a rotating member is an intermittent change, not a continuous change in color. Furthermore, providing the adapter attachment / detachment structure or the rotation structure of the rotating member at the distal end of the endoscope body complicates the distal end structure of the endoscope body, which is an obstacle to downsizing the endoscope body. It became.

  The present invention has been devised in view of the above-described conventional situation, and can easily and continuously switch the color of illumination light while observing a site to be observed without complicating the distal end structure of the endoscope body. An object is to provide an endoscope.

  The present invention provides a light source that emits light of a specific wavelength, an optical unit that collects the specific wavelength light emitted from the light source, and converts the wavelength of the specific wavelength light collected by the optical unit to different wavelengths. A phosphor having a plurality of layers, a condensing position control unit for condensing the specific wavelength light emitted from the light source on any of the layers of the phosphor, and any of the layers of the phosphor And an illumination fiber that irradiates the light emitted from the phosphor in response to the light condensing and irradiates the incident light toward the observation target.

  According to the present invention, the color of illumination light can be easily and continuously switched while observing a site to be observed without complicating the distal end structure of the endoscope body.

The figure which shows an example of a principal part structure of the endoscope of 1st Embodiment. The figure which shows an example of the whole structure of the endoscope of each embodiment. The figure which shows an example of a structure of the camera in the endoscope of each embodiment. Enlarged view of the main part of the camera head shown in FIG. (A) Cross-sectional view of the wavelength conversion unit arranged in the phosphor on the light source side, (B) Cross-sectional view of the wavelength conversion unit arranged in the phosphor on the illumination fiber side. (A) Cross-sectional view of a wavelength conversion unit according to a modification provided with three layers of phosphors, (B) Cross-sectional view of a wavelength conversion unit with a non-uniform phosphor film thickness, (C) Phosphor concentration distribution Sectional view of wavelength converter with different Graph showing an example of the relationship between phosphor output light energy and excitation light input energy Main part block diagram of endoscope of 2nd Embodiment Explanatory drawing showing an example of shades obtained by controlling the irradiation of excitation light to different phosphors Explanatory drawing showing an example of the pulse emission number of the excitation light corresponding to 1 frame of a captured image (A) Front view of a holding unit according to a modification in which a plurality of phosphors are irregularly arranged in the circumferential direction, (B) Holding in which the phosphor is provided by dividing the circumferential direction into a plurality of arcs Front view

  Hereinafter, an embodiment (hereinafter referred to as “the present embodiment”) that specifically discloses the configuration and operation of an endoscope according to the present invention will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

  FIG. 1 is a diagram illustrating an example of a main configuration of the endoscope 11 according to the first embodiment. The endoscope 11 of the present embodiment is used for observing the state of an affected part (for example, blood vessels, lymph nodes, upper gastrointestinal tract) in a human body in, for example, a treatment, and at least a light emitting element 13 as an example of a light source, An optical unit 15 composed of a plurality of lenses, a phosphor having a plurality of layers formed on the substrate SUB (specifically, a layer of phosphor 17 and a layer of phosphor 19), and an illumination fiber 21 And the condensing position control unit 23.

  In the endoscope 11 shown in FIG. 1, a configuration relating to an optical system (for example, the wavelength of excitation light as a result of condensing blue excitation light emitted from the light emitting element 13 on the phosphor 17 layer or the phosphor 19 layer). 1 is a diagram illustrating a configuration in which light converted into a different wavelength (hereinafter referred to as “fluorescence”) is incident on the illumination fiber 21 and irradiated, and a configuration related to the imaging system of the endoscope 11 (for example, the body of a patient). The configuration for capturing an image showing the state of the above is omitted.

  FIG. 2 is a diagram illustrating an example of the overall configuration of the endoscope 11 according to each embodiment. The endoscope 11 is roughly divided into a video processor 25, a monitor 27, and a camera 29 as an imaging unit or an endoscope unit. The camera 29 includes a plug 31 that can be connected to a video processor, an in-vivo insertion portion 33, and a camera head 35. The illumination fiber 21 having a role as a light guide is inserted into the in-body insertion portion 33. The illumination fiber 21 may be a single fiber or a bundle of a plurality of fibers. In this embodiment, the illumination fibers 21 are a pair (that is, two). Moreover, in addition to the illumination fiber 21, the transmission cable 37 (refer FIG. 4) is integrally attached to the insertion part 33 in a body. The transmission cable 37 includes, for example, a plurality of wires (signal lines, power lines, ground lines, etc.). In the present embodiment, the endoscope 11 has a small diameter. In the small-diameter endoscope 11, the maximum outer diameter of the exterior part 43 described later is about 3.0 mm or less.

  The camera 29 may have an operation unit (not shown) in addition to the above configuration. The operation unit performs an operation for bending or observing the camera head 35. In the camera 29, a space between the operation unit and the camera head 35 is an in-vivo insertion unit 33. That is, in the camera 29, the camera head 35 and the in-body insertion portion 33 are inserted into the body cavity, and the operation portion is operated outside the body, thereby performing a procedure such as observation.

  The video processor 25 includes a processor (not shown) that processes image data from the image sensor 39. The video processor 25 is electrically connected to the camera 29 by connecting a plug 31 provided at the end of the camera 29. The processor performs image processing on the captured image data transmitted from the camera 29 based on an instruction from the operation unit or the keyboard of the camera 29, generates image data that can be displayed on the monitor 27, and outputs the image data to the monitor 27. Supply.

  FIG. 3 is a diagram illustrating an example of the configuration of the camera 29 in the endoscope 11 according to each embodiment. In the camera 29, the plug 31 is detachably connected to a socket provided as a connection portion with the plug 31 in the video processor 25. The plug 31 is provided with a card edge substrate 41 connected to the card edge connector of the socket.

  The plug 31 is provided with a light emitting element 13 as an example of a light source that emits light having a specific wavelength (hereinafter simply referred to as “specific wavelength light”, for example, blue excitation light). In the present embodiment, for example, a laser diode element (LD) is used as the light emitting element 13. As the laser diode element, an InGaN-based laser diode can be used, and an InGaNAs-based laser diode, a GaNAs-based laser diode, or the like can also be used. In addition, it is good also as a structure using semiconductor light emitting elements, such as a light emitting diode element (LED), for the said light source. In addition to the semiconductor light emitting element, the light source may be light obtained by selecting a wavelength of light from a white light source such as a xenon lamp using a color filter. The light emitting element 13 generates and emits light (for example, blue excitation light) by power supplied from the power supply circuit of the video processor 25 through the plug 31.

  FIG. 4 is an enlarged view of a main part of the camera head 35 shown in FIG. The camera head 35 has a hard exterior portion 43 formed in a cylindrical shape made of a SUS tube or the like. A flexible exterior portion 45 formed in a cylindrical shape made of PFA (polytetrafluoroethylene) or the like is connected to the exterior of the in-body insertion portion 33. The exterior portion 43 includes a pair of irradiation ports 47 that irradiate the observation region with light from the illumination fiber 21, and a CCD (Charge Coupled Device) image sensor or CMOS (Complementary Metal-Oxide) that acquires image data of the observation region. Semiconductor) An image sensor 39 such as an image sensor is disposed. The image sensor 39 is connected to the transmission cable 37. A lens unit 49 including an objective lens is disposed on the light receiving surface side of the image sensor 39.

  Incidentally, in the plug 31 shown in FIG. 3, the wavelength of the specific wavelength light (that is, blue excitation light) from the light emitting element 13 is changed between the light emitting element 13 and the illumination fiber 21 to another wavelength (for example, the illumination fiber 21). A wavelength converter 51 is provided for converting the light emitted from the light into a wavelength for obtaining yellow fluorescent light necessary for white light. The wavelength conversion unit 51 includes an optical unit 15, a phosphor formed on the substrate SUB (that is, two layers of phosphors 17 and 19), and a condensing position control unit 23 (see FIG. 1). The optical unit 15 condenses the light from the light emitting element 13. The optical unit 15 includes a collimator lens 53 that refracts specific wavelength light from the light emitting element 13 into light parallel to the optical axis direction, and a phosphor formed on the substrate SUB by refracting collimated light in a direction intersecting the optical axis. And a condenser lens 55 for condensing light on any one of the layers. The substrate SUB is formed using, for example, sapphire or glass as a member, and can transmit blue excitation light that is collimated light.

In the wavelength conversion unit 51, the phosphor formed on the substrate SUB has a plurality of layers for converting light emitted from the optical unit 15 into different wavelengths. For example, the phosphor shown in FIG. 1 includes two layers of a phosphor 17 and a phosphor 19. That is, the phosphor constitutes a laminate 57 composed of the phosphor 17 and the phosphor 19. The phosphors 17 and 19 are converted to other wavelengths having different blue wavelengths (for example, wavelengths corresponding to yellow fluorescence and fluorescence with strong redness) by being excited by light of a specific wavelength from the light emitting element 13. Light is emitted. The phosphors 17 and 19 absorb a part of light of a specific wavelength (for example, blue laser light) from the light emitting element 13 and, for example, a plurality of types of phosphor materials (for example, YAG phosphor, or BAM _(BaMgAl 10 _{O 17)} phosphor) may be configured to include such. As a result, green to yellow excitation light that uses blue laser light as excitation light and blue laser light that is transmitted without being absorbed by the phosphors 17 and 19 are combined to produce white (that is, pseudo white) light. (Hereinafter referred to as “illumination light”) can be generated. This illumination light is incident on the illumination fiber 21.

  The illumination light incident on the illumination fiber 21 is irradiated from the camera head 35 toward the observation region of the subject (for example, a patient). Then, the state of the observation region irradiated with the illumination light is imaged by the imaging unit 39 by forming a subject image with the lens unit 49.

  The image data of the captured image output from the image sensor 39 is transmitted to the A / D converter of the video processor 25 through the transmission cable 37, converted into a digital signal, and input to the image processor of the video processor. The image processing unit performs various processes such as white balance correction, gamma correction, edge enhancement, and color correction on the image data from the image sensor 39 converted into a digital signal. The image data processed by the image processing unit is displayed on the monitor 27 as image data that can be displayed on the monitor 27 together with various information. Moreover, it is memorize | stored in the memory | storage part which consists of memory and a storage apparatus as needed.

  The condensing position control unit 23 relatively moves the optical unit 15 and the phosphors 17 and 19 so that the light emitted from the optical unit 15 is collected on any layer of the phosphor. Relative movement means that either one of the optical unit 15 and the phosphor may move or both may move. However, it is a condition that the distance between the two changes due to movement. As a result, the condensing position control unit 23 can place the focal point 59 at an arbitrary position in the thickness direction of the stacked body 57 composed of the phosphors 17 and 19.

  In the present embodiment, the condensing position control unit 23 moves the optical unit 15 and the phosphor relative to each other in the direction along the optical axis (the direction of the arrow a in the figure), so The focal point 59 is switched to the phosphor 17 or the phosphor 19).

  The endoscope 11 can be used for endoscopic diagnosis in which fine lesions are captured by special light observation. Examples of special light observation include narrow-band light observation that highlights surface blood vessels, fluorescence observation that observes autofluorescence of the living body, infrared light observation that extracts blood vessel information in the deep layer by fluorescence from the injected drug, etc. Can do. In normal observation, white light illumination is used, whereas in narrow-band light observation and fluorescence observation, for example, light with a wavelength of 405 nm is used as illumination light, and in infrared light observation, for example, light with a wavelength of 760 nm is used as illumination light. In addition, light having a wavelength of 405 nm is used as illumination light for photodynamic diagnosis (PDD), and light having a wavelength of 630 nm is used as illumination light for photodynamic therapy (PDT).

  In addition, for example, a plaque (cove on the inner wall of a blood vessel) that causes arteriosclerosis is greatly different in light spectrum reflection characteristics from normal aortic internal tissue. For example, if image analysis is performed at 580 nm (yellow region), it is possible to observe a difference between a region with a large plaque and a region with a small plaque. For example, “Martin R. P. et al.,“ Preferential Light Absorption in Atheromas In Vitro ”(1986)” is cited as a reference for reflection characteristics. In this reference, the reflectance of “aorta” and “atherome” in the range of 250 to 1300 nm is measured, and graph data is read and converted into numerical data. The aorta has a gray reflection characteristic and the asterome has a yellow reflection characteristic. If a wavelength of 580 nm or later is used as illumination light, the difference becomes large, and an improvement in color difference can be expected.

  The wavelength conversion unit 51 of this embodiment is provided in the plug 31. In addition, the endoscope 11 of the present embodiment can also include the wavelength conversion unit 51 in the video processor 25. In this case, an optical connection mechanism provided with a ferrule or the like for causing the illumination light from the video processor 25 to enter the illumination fiber 21 of the camera 29 is used at the connection portion between the video processor 25 and the plug 31 of the camera 29.

  Next, the operation of the endoscope 11 of the present embodiment will be described with reference to FIGS. 5 (A) and 5 (B). FIG. 5A is a cross-sectional view of the wavelength conversion unit 51 in which the focal point 59 is disposed on the phosphor 17 on the light source side. FIG. 5B is a cross-sectional view of the wavelength conversion unit 51 in which the focal point 59 is disposed on the phosphor 19 on the illumination fiber 21 side.

  In the endoscope 11 of the present embodiment, the specific wavelength light emitted from the light emitting element 13 that is a light source is collected by the optical unit 15. That is, in the optical unit 15, the light beam of the specific wavelength incident in parallel with the optical axis intersects the optical axis and the focal point 59. The condensing position control unit 23 relatively moves the optical unit 15 and the phosphors 17 and 19. As a result, the focal point 59 is formed of different phosphors (specifically, phosphor 17 or phosphors) formed as a plurality of layers for converting the wavelength of the specific wavelength light into different wavelengths by the condensing position control unit 23. 19) Move to one of the layers.

  The phosphors 17 and 19 emit fluorescent light obtained by converting the wavelength of the specific wavelength light into a different wavelength in the vicinity of the focal point 59 moving. Further, a part of the specific wavelength light (that is, blue excitation light) from the light emitting element 13 is not excited in the phosphors 17 and 19 but is transmitted through the phosphors 17 and 19 as they are. The light incident on the illumination fiber 21 becomes light (illumination light) in which the fluorescence having these different wavelengths and the specific wavelength light are mixed. By changing the position of the focal point 59 by the condensing position control unit 23, fluorescence converted into different wavelengths can be obtained. Further, by changing the position of the focal point 59, the ratio of the fluorescence and the specific wavelength light (that is, the excitation light) in all illumination light components can be increased or decreased continuously (that is, not intermittently). Thereby, the illumination light of the color balance shown in FIG. 5A is obtained and enters the illumination fiber 21, and the illumination light of the color balance shown in FIG. 5B is obtained and enters the illumination fiber 21. . The phosphor (layer of phosphor 17) in which the position of the focal point 59 shown in FIG. 5A is formed, and the phosphor (layer of phosphor 19) in which the position of the focal point 59 shown in FIG. 5B is formed. Therefore, the color balances shown in FIGS. 5A and 5B are different.

  FIG. 7 is a graph showing an example of the relationship between the output light energy of the phosphor and the input light energy of the excitation light. In FIG. 7, the phosphor A layer indicates, for example, a layer of the phosphor 17 (see FIG. 1). The phosphor B layer is, for example, a layer of phosphor 19 (see FIG. 1). FIG. 7 shows the input light energy and the output light energy of the phosphor when the focal point 59 is positioned on the phosphor 17 shown in FIG.

  In FIG. 7, the region where the relationship between excitation light (that is, input light energy) and fluorescence (that is, output light energy) is linear is the phosphor A layer or the phosphor B layer, and excitation that is input light energy. In the process in which each phosphor absorbs a part of light and emits fluorescence, this is a region where the ratio of the increase in fluorescence to the increase in excitation light maintains a linear relationship.

  A region where the relationship between excitation light (that is, input light energy) and fluorescence (that is, output light energy) is curved will be described below.

  When the input light energy of the specific wavelength light emitted from the light emitting element 13 (that is, blue excitation light) is X, the excitation light is condensed in the phosphor A layer, so that the input light energy density is too high. is there. For this reason, in the phosphor A layer in which the input light energy density becomes too high, the relationship between the excitation light input light energy and the fluorescence output light energy is nonlinear due to the effects of “excitation saturation” and “temperature quenching”. Become. In other words, the amount of emitted fluorescence is reduced and the fluorescence efficiency is degraded.

  On the other hand, in the phosphor B layer, when the input light energy of the specific wavelength light (that is, blue excitation light) emitted from the light emitting element 13 is X, the phosphor B layer is incident on the phosphor B layer compared to the phosphor A layer. The input light energy density is low due to the large surface area of the excitation light, and it is not affected by “excitation saturation” and “temperature quenching”, and the relationship between the input light energy of the excitation light and the output light energy of the fluorescence is linear. . As described above, it can be seen that the wavelength conversion efficiency in the phosphor is easily influenced by the input light energy of the excitation light, and when the input light energy density of the excitation light becomes too high, it becomes lower than a certain temperature. For this reason, it is desirable that the temperature rise of the phosphor is suppressed by a cooling unit (not shown) or the like.

  As described above, the endoscope 11 of the present embodiment is illuminated while being observed by a user (for example, a doctor) without complicating the structure of the tip (that is, the camera head 35) of the endoscope body (that is, the camera 29). It is possible to change the hue of light. Further, the endoscope 11 can continuously change the color of the illumination light sent to the illumination fiber 21 by moving the focal point 59 in the thickness direction of the stacked body 57 by the condensing position control unit 23. .

  Further, in the endoscope 11, the optical unit 15 and the phosphor are relatively moved by the condensing position control unit 23. The distance between the optical unit 15 and the phosphor changes due to relative movement. As a result, the focal point 59 can be moved to the desired phosphor by a simple mechanism. For example, when the optical unit 15 includes a light source side collimator lens 53 and a phosphor side condenser lens 55, the focal point 59 can be moved by moving the condenser lens 55 along the optical axis. .

  Next, an endoscope 11 according to a modification of the first embodiment will be described with reference to FIGS. FIG. 6A is a cross-sectional view of a wavelength conversion unit 61 according to a modification in which three layers of phosphors 17, 19, and 67 are provided. FIG. 6B is a cross-sectional view of the wavelength conversion unit 63 in which the phosphor film thickness is not uniform. FIG. 6C is a cross-sectional view of the wavelength conversion unit 65 having a different phosphor concentration distribution.

  In the wavelength converter 61 of the endoscope 11 shown in FIG. 6A, three layers of phosphors 17, 19, and 67 are formed on the substrate SUB. Thus, the endoscope 11 can be provided with three or more layers of phosphors. In this wavelength conversion unit 61, it is possible to more easily obtain a wide range of desired shades as compared with the case where the two layers of phosphors 17 and 19 are provided.

  The wavelength converter 63 of the endoscope 11 shown in FIG. 6B has a thickness of each layer of phosphors (phosphors 17 and 19) formed on the substrate SUB at each position in a direction perpendicular to the optical axis. Is different. In this case, in the endoscope 11, the condensing position control unit 23 is relative to the optical unit 15 and the phosphor (that is, the phosphors 17 and 19) in the direction intersecting the optical axis (the direction of the arrow b in the figure). Move. Relative movement means that either one of the optical unit 15 and the phosphor may move or both may move. However, the condition is that the incident position of the specific wavelength light on the surface of the laminate changes as a result of movement.

  In the wavelength conversion unit 63, a plurality of phosphors overlap in the direction along the optical axis to form a stacked body 69. The specific wavelength light is incident on the stacked body 69 from the surface of one stacked body in the stacking direction of the stacked body 69. In the laminate 69, the ratios of the thicknesses of the phosphors 17 and 19 in the respective layers are different at different positions on the laminate surface orthogonal to the optical axis. That is, the condensing position control unit 23 can increase or decrease the ratio of each fluorescence in all illumination light components by causing the specific wavelength light to be incident on different positions on the surface of the stacked body. Moreover, the condensing position control part 23 can also increase / decrease the ratio of fluorescence and specific wavelength light simultaneously.

  In this endoscope, the position of the specific wavelength light incident on the surface of the laminated body is changed by relatively moving the optical unit 15 and the phosphor in the direction intersecting the optical axis.

  In the wavelength converter 65 of the endoscope 11 shown in FIG. 6C, a phosphor 71 having a concentration distribution is formed on the substrate SUB in the film thickness direction. In the wavelength conversion unit 65, continuous gradation can be easily obtained.

  Next, an endoscope 11A according to a second embodiment will be described with reference to the drawings.

  FIG. 8 is a main part configuration diagram of the endoscope 11A of the second embodiment. In addition, the same code | symbol is attached | subjected to the member same as the member shown in FIGS. 1-6, and the overlapping description is abbreviate | omitted. The endoscope 11A according to the present embodiment includes at least a light emitting element 13 as an example of a light source, a light emission control unit 79 that controls driving of the light emitting element 13 as an example of a light source, and an optical device that includes a plurality of lenses. The unit 73 includes a plurality of phosphors (specifically, phosphors 17 and 19) applied on the holding unit 81, an illumination fiber 21, and a phosphor moving unit 75. In the endoscope 11A of the present embodiment, the optical unit 73 and the phosphor moving unit 75 are different from the endoscope 11 of the first embodiment. The optical unit 73 and the phosphor moving unit 75 constitute a wavelength converting unit 77.

  The light emission control unit 79 controls a light emission drive circuit provided in the video processor 25 so that the light emitting element 13 emits light periodically at a predetermined timing.

  The phosphor moving unit 75 places any of a plurality of different phosphors on the optical path of the optical unit 73.

  In the present embodiment, the phosphor moving unit 75 includes a holding unit 81 and a rotation driving unit 83. The holding part 81 is a housing formed of a disc shape having a plurality of different phosphors arranged at predetermined intervals in the circumferential direction and having light transmittance. In the present embodiment, 16 different two types of phosphors 17A and 19A are applied and arranged on the circumference of the holding portion 81 (see FIG. 9). The rotation driving unit 83 rotates the holding unit 81 around a central axis that passes through the center of the holding unit 81.

  When the light emission control unit 79 receives an operation signal corresponding to a user operation (for example, an operation by a switch (not shown) of a doctor or an assistant during the operation), a plurality of different light emission control units 79 are synchronized with the rotation of the holding unit 81. Of the phosphors (that is, phosphors 17A and 19A), only a specific phosphor is irradiated with light having a specific wavelength (that is, blue excitation light). The holding part 81 is made of a material having a high thermal conductivity. Furthermore, the holding part 81 is made of a material having a high light transmittance.

FIG. 9 is an explanatory diagram illustrating a color example obtained by pulse-controlling irradiation of excitation light to different phosphors.
In the endoscope 11A, the light emission control unit 79 rotates the holding unit 81 in the circumferential direction, and performs pulse control of irradiation with the specific wavelength light (that is, blue excitation light) from the light emitting element 13, for example, the phosphor 17A. Only light having a specific wavelength (that is, blue excitation light) is irradiated. Then, a part of the blue excitation light is absorbed by the phosphor 17A, and illumination light having a hue A1 in which the wavelength-converted fluorescence (that is, yellow fluorescence) and the blue excitation light itself are mixed is obtained.

  In the endoscope 11A, the light emission control unit 79 rotates the holding unit 81 in the circumferential direction, and performs pulse control of irradiation with the specific wavelength light (that is, blue excitation light) from the light emitting element 13, for example, the phosphor 19A. Only light having a specific wavelength (that is, blue excitation light) is irradiated. Then, a part of the blue excitation light is absorbed by the phosphor 19A, and illumination light having a hue B1 in which the fluorescence converted in wavelength (that is, fluorescence with strong redness) and the blue excitation light itself are mixed is obtained.

  In the endoscope 11A, the light emission control unit 79 rotates the holding unit 81 in the circumferential direction, and performs pulse control of irradiation with the specific wavelength light (that is, blue excitation light) from the light emitting element 13, for example, the phosphor 17A. , 19A are irradiated with specific wavelength light (that is, blue excitation light). Then, a part of the blue excitation light is absorbed by the phosphor 17A and converted in wavelength (that is, yellow fluorescence), and a part of the blue excitation light is absorbed in the phosphor 19A and converted in wavelength (the wavelength converted). That is, illumination light having a hue C1 in which the fluorescence having strong redness and the blue excitation light itself are mixed can be obtained.

  FIG. 10 is an explanatory diagram illustrating an example of the number of excitation light pulses corresponding to one frame of a captured image. The endoscope 11A transmits blue excitation light, which is light having a specific wavelength, from the light emitting element 13 while synchronizing with an imaging frame by the imaging element 39, and the phosphor 17A or the phosphor 19A, or the phosphor 17A and the fluorescence of the holding unit 81. The body 19A is periodically irradiated. The hues A1, B1, and C1 have been described with reference to FIG.

  In this case, when the imaging frame rate of the endoscope 11A is 60 fps, the reading time (imaging period) of one frame is 0.017 sec (= 17 msec). For example, in the case where 60 phosphors 17A and 19A are arranged on the circumference of the holding unit 81, if the holding unit 81 rotates at 1000 rpm, the number of the phosphors 17A and 19A becomes 17 × 60 / min. Is irradiated with excitation light. Therefore, the endoscope 11A can pulse-emit blue excitation light to 17 phosphors in one frame in the wavelength converter 77. In other words, the endoscope 11A can irradiate illumination light (that is, pseudo white color) in which blue excitation light and yellow fluorescence are mixed in one frame 17 times, or blue excitation light and redness are emitted in one frame. Illumination light mixed with strong fluorescence can be irradiated 17 times, or illumination light mixed with blue excitation light, yellow fluorescence, and strong redness can be irradiated 17 times in one frame.

  FIG. 11A is a front view of a holding portion 85 according to a modified example in which a plurality of phosphors are irregularly arranged in the circumferential direction. FIG. 11B is a front view of the holding portion 87 in which the phosphor is provided by dividing the circumferential direction into a plurality of arcs. In the endoscope 11A, the phosphors 17A, the phosphors 19A, and the phosphors 67 are arranged in a predetermined arrangement pattern like the holding unit 85 shown in FIG. It may be a thing. Further, as in the holding portion 87 shown in FIG. 11B, two or more kinds of phosphors 17A, phosphors 19A, and phosphors C67 are applied with fluorescence divided into a plurality of arcs. May be provided.

  As described above, in the endoscope 11 </ b> A of the present embodiment, the phosphor moving unit 75 selectively places any one of the plurality of different phosphors 17 </ b> A and 19 </ b> A that perform different wavelength conversions on the optical path. At this time, only when the desired phosphor is disposed on the optical path, the light emission control unit 79 can cause the specific wavelength light to enter the phosphor. Therefore, it is possible to mix fluorescence of different wavelengths within a unit time. That is, the ratio of the plurality of fluorescence and the specific wavelength light (that is, blue excitation light) in all illumination light components can be continuously increased or decreased. Thereby, the endoscope 11 </ b> A can continuously change the hue of the illumination light sent to the illumination fiber 21.

  In the endoscope 11 </ b> A, a plurality of different phosphors are arranged concentrically on the holding portion 81. The optical unit 73 causes the specific wavelength light to enter one place on the concentric circle. When the holding unit 81 is rotated by the rotation driving unit 83, different phosphors are sequentially arranged at the incident portions of the specific wavelength light. At this time, when a desired phosphor is disposed at an incident location, light of a specific wavelength is incident. By making light of a specific wavelength incident on a desired phosphor by the light emission control unit 79, it becomes possible to mix fluorescence of different wavelengths within a unit time. That is, the ratio of fluorescence and specific wavelength light in all illumination light components can be continuously increased or decreased. Thereby, the endoscope 11 </ b> A can continuously change the hue of the illumination light sent to the illumination fiber 21.

  Further, in the endoscope 11A, the fluorescent component by a specific phosphor is increased, and the color tone is easily emphasized.

  Further, in the endoscope 11A, the temperature rise of the holding unit 81 due to the irradiation with the specific wavelength light is suppressed. Thereby, the endoscope 11A can suppress the phosphor from becoming high temperature, and can suppress a decrease in the wavelength conversion efficiency of the phosphor due to the influence of excitation saturation, temperature quenching, and the like.

  Further, in the endoscope 11A, the light transmittance of the holding unit 81 is increased, so that the specific wavelength light passes through the holding unit 81 and enters the phosphor (the phosphor is provided on the light source side of the holding unit 81). Or when the fluorescence excited by the specific wavelength light is transmitted through the holding unit 81 (when the phosphor is provided on the illumination fiber side of the holding unit 81), the light use efficiency is increased and the light intensity is increased. High illumination light can be obtained.

  As described above, the embodiments of the endoscope according to the present invention have been described with reference to the drawings, but the present disclosure is not limited to such examples. It is obvious for those skilled in the art that various changes, modifications, substitutions, additions, deletions, and equivalents can be conceived within the scope of the claims. Of course, it is understood that it belongs to the technical scope of the present disclosure.

DESCRIPTION OF SYMBOLS 11, 11A Endoscope 13 Light emitting element 15 Optical part 17 Phosphor 19 Phosphor 21 Illumination fiber 23 Condensing position control part 25 Video processor 27 Monitor 53 Collimating lens 55 Condenser lens 57 Laminate 59 Focus 75 Phosphor moving part 79 Light emission Control unit 81 Holding unit 83 Rotation drive unit

Claims (4)

A light source that emits light of a specific wavelength;
An optical unit for condensing the specific wavelength light emitted from the light source;
A phosphor having a plurality of layers that convert the wavelengths of the specific wavelength light collected by the optical unit into different wavelengths, and
A condensing position control unit that condenses the specific wavelength light emitted from the light source on any of the layers of the phosphor;
An illumination fiber that enters the light emitted from the phosphor in response to light collection on any one of the layers of the phosphor, and irradiates the incident light toward the observation target; and
Endoscope. The endoscope according to claim 1, wherein
The condensing position control unit collects the specific wavelength light emitted from the light source in one of the layers of the phosphor by relatively moving the optical unit and the phosphor along the optical axis. Light,
Endoscope. The endoscope according to claim 1, wherein
Each of the layers of the phosphors has a different thickness at each position in a direction perpendicular to the optical axis.
Endoscope. The endoscope according to claim 3, wherein
The condensing position control unit moves the phosphor relative to the optical unit in a direction intersecting the optical axis;
Endoscope.

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