JP5173663B2 - LIGHT SOURCE DEVICE AND ENDOSCOPE DEVICE USING THE SAME - Google Patents

Description

  The present invention relates to a light source device.

Currently, an endoscope apparatus including a light source device that sequentially emits red light, green light, and blue light is known. Japanese Patent Laying-Open No. 2003-19112 discloses one such endoscope. In this endoscope, the light source device has three fluorescent fibers that emit red light, green light, and blue light, and the light incident ends of the three fluorescent fibers are connected to three excitation light sources, respectively. The light emission ends of the three fluorescent fibers are connected to the light incident ends of one optical fiber extending through the endoscope insertion portion. The three excitation light sources are sequentially turned on and off, and the corresponding fluorescent fibers are excited to emit fluorescence. The emitted fluorescence propagates through the optical fiber and is emitted from the light exit end of the optical fiber located at the distal end portion of the endoscope insertion portion.
JP 2003-19112 A

  In this light source device, most of the fluorescence generated by the fluorescent fiber is dissipated out of the optical fiber. Moreover, although three fluorescent fibers are connected to one optical fiber, it is difficult to connect the three fluorescent fibers to one optical fiber with high coupling efficiency. For this reason, it is difficult to obtain illumination light with sufficient brightness. Moreover, use of an optical member or the like for improving the coupling efficiency leads to an increase in the size of the apparatus.

  An object of the present invention is to provide a compact light source device that emits bright illumination light and can switch colors.

  The light source device of the present invention includes a first light source that emits first excitation light, a second light source that emits second excitation light, and the first excitation light emitted from the first light source. A first optical fiber that guides the second excitation light emitted from the second light source, and the first excitation light emitted from the first optical fiber. A first phosphor that emits a first fluorescence when excited by the light, and a second fluorescence that is different from the first fluorescence when excited by the second excitation light emitted from the second optical fiber. And a second phosphor. The first phosphor and the second phosphor are arranged side by side in the light emitting end direction, and the second phosphor is located closer to the light emitting end than the first phosphor. The light emission end faces of the first and second optical fibers are opposed to the first phosphor. The first phosphor transmits the second excitation light. The second phosphor has a first optical aperture that transmits the first fluorescence.

  ADVANTAGE OF THE INVENTION According to this invention, the small light source device which can switch the color which inject | emits bright illumination light is provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First embodiment]
<Configuration>
A light source device according to a first embodiment of the present invention is shown in FIG. As shown in FIG. 1, the light source device is a device that emits illumination light, and includes three excitation light sources 10A, 10B, and 10C, three optical fibers 20A, 20B, and 20C, and one wavelength conversion unit 40. Have. The wavelength conversion unit 40 includes three phosphors 30A, 30B, and 30C.

  The excitation light source 10A emits excitation light that excites the phosphor 30A. The excitation light source 10B emits excitation light that excites the phosphor 30B. The excitation light source 10C emits excitation light that excites the phosphor 30C. Excitation light emitted from the excitation light sources 10A, 10B, and 10C may be light having a wavelength that can excite the phosphors 30A, 30B, and 30C, respectively. Even light having different wavelengths may be light having the same wavelength. It may be. When each of the phosphors 30A, 30B, and 30C is turned on and off independently, the excitation light emitted from the excitation light sources 10A, 10B, and 10C can excite only the corresponding phosphors 30A, 30B, and 30C. It is desirable to transmit other phosphors. In the present embodiment, the phosphor and the excitation light source are selected so that they can be turned on and off independently.

  The excitation light sources 10A, 10B, and 10C are the semiconductor lasers 12A, 12B, and 12C that emit excitation light, and the lenses 14A that cause the excitation light emitted from the semiconductor lasers 12A, 12B, and 12C to enter the optical fibers 20A, 20B, and 20C, respectively. , 14B, 14C.

  The optical fiber 20A guides the excitation light emitted from the excitation light source 10A. The optical fiber 20B guides the excitation light emitted from the excitation light source 10B. The optical fiber 20C guides the excitation light emitted from the excitation light source 10C.

  The excitation light sources 10A, 10B, and 10C have high coupling efficiency with the optical fibers 20A, 20B, and 20C because the light emitting elements are constituted by the semiconductor lasers 12A, 12B, and 12C. For example, when the optical fibers 20A, 20B, and 20C are composed of multimode fibers, a coupling efficiency of 70% or more can be obtained.

  The phosphors 30A, 30B, 30C in the wavelength conversion unit 40 are shown in FIG. In FIG. 2, the right side is the light emitting end direction. As shown in FIG. 2, the phosphors 30A, 30B, and 30C are arranged side by side in the light emitting end direction. The phosphor 30B is located closer to the light emission end than the phosphor 30A, and the phosphor 30C is located closer to the light emission end than the phosphor 30B.

  The phosphor 30A is excited by excitation light emitted from the optical fiber 20A and emits first fluorescence. The phosphor 30A transmits the excitation light emitted from the optical fiber 20B and the excitation light emitted from the optical fiber 20C. The phosphor 30B is excited by the excitation light emitted from the optical fiber 20B and emits second fluorescence. The phosphor 30B transmits excitation light emitted from the optical fiber 20C. The phosphor 30C is excited by the excitation light emitted from the optical fiber 20C and emits third fluorescence. The wavelength of the first fluorescence is longer than the wavelength of the second fluorescence, and the wavelength of the second fluorescence is longer than the wavelength of the third fluorescence. For example, the phosphor 30A is composed of a red phosphor that emits red fluorescence, the phosphor 30B is composed of a green phosphor that emits green fluorescence, and the phosphor 30C is a blue phosphor that emits blue fluorescence. Composed. Furthermore, the phosphor 30 </ b> B has a through hole 32, and the phosphor 30 </ b> C has a through hole 34 and a through hole 36.

  In the following description, it is assumed that the phosphor 30A is basically composed of a red phosphor, the phosphor 30B is composed of a green phosphor, and the phosphor 30C is composed of a blue phosphor.

  Here, the phosphor may be composed of a single crystal phosphor or a transparent polycrystalline phosphor, and a normal powder phosphor or a so-called nanophosphor is sealed in a member such as a resin. It may be constituted by solidified. Furthermore, any phosphor may be used as long as it is a commonly used phosphor such as a fluorescent glass in which an element serving as a light emission center is added to glass or the like.

  FIGS. 3, 4, and 5 show the phosphors 30 </ b> A, 30 </ b> B, and 30 </ b> C as viewed from the light exit end direction of the wavelength conversion unit 40. As shown in FIGS. 3 to 5, the phosphors 30 </ b> A, 30 </ b> B, and 30 </ b> C each have a rotationally symmetric outline in projection onto a plane perpendicular to the light exit end direction. For example, each of the phosphors 30A, 30B, and 30C has a disk shape, and has a circular outline when projected onto a plane perpendicular to the light emitting end direction. This is because the beam pattern of the excitation light emitted from the optical fibers 20A, 20B, and 20C is substantially circular.

  As shown in FIG. 4, the phosphor 30 </ b> B has three through holes 32. The through holes 32 are arranged at equal intervals at positions equidistant from the center of the phosphor 30B having a circular outline. That is, the through holes 32 are arranged rotationally symmetrically with respect to the rotationally symmetric axis of the phosphor 30B having a circular outline. Specifically, the through-holes 32 are arranged substantially at the vertices of an equilateral triangle 37 having a center of gravity at the center of the phosphor 30B having a circular outline at the center thereof. The through hole 32 is for transmitting the red fluorescence emitted from the phosphor 30A. That is, the through hole 32 constitutes an optical opening that transmits red fluorescence emitted from the phosphor 30A.

  As shown in FIG. 5, the phosphor 30 </ b> C has three through holes 34 and three through holes 36. The through holes 34 and 36 are arranged at equal intervals at positions equidistant from the center of the phosphor 30C having a circular outline. That is, the through holes 34 and 36 are rotationally symmetric with respect to the rotationally symmetric axis of the phosphor 30B having a circular outline. Specifically, the through holes 34 and 36 are alternately arranged at the vertices of a regular hexagon 38 having the center of gravity at the center of the phosphor 30C having a circular outline. The through hole 34 is for transmitting red fluorescence emitted from the phosphor 30A, and the through hole 36 is for transmitting green fluorescence emitted from the phosphor 30B. That is, the through holes 34 and 36 constitute an optical opening that transmits the red fluorescence emitted from the phosphor 30A and the green fluorescence emitted from the phosphor 30B.

  The phosphor 30B and the phosphor 30C are arranged so that the through hole 32 and the through hole 34 overlap each other in projection onto a plane perpendicular to the light emitting end direction. That is, the through hole 32 and the through hole 34 are aligned. In other words, in the projection onto a plane perpendicular to the light emitting end direction, the optical aperture formed by the through holes 32 partially overlaps the optical aperture formed by the through holes 34 and 36.

  The size of the through hole 32 formed in the phosphor 30B and the size of the through holes 34 and 36 formed in the phosphor 30C is such that the mixed color of each fluorescence emitted from the light exit end becomes a desired color. Adjusted. That is, the red fluorescence as the sum of the red fluorescence passing through the through hole 32 and the through hole 34, the red fluorescence passing through the green phosphor 30B and the blue phosphor 30B, the green fluorescence passing through the through hole 36, and the phosphor The sizes of the through holes 32, 34, and 36 are adjusted so that the green fluorescence as the sum of the green fluorescence transmitted through 30C and the sum of the blue fluorescence emitted from the phosphor 30C have a desired color.

  Here, an example in which the number of through holes 32, 34, and 36 is three is shown, but the number of through holes 32, 34, and 36 is not limited to three.

  As shown in FIG. 6, the wavelength conversion unit 40 includes a housing 42 that holds the phosphors 30 </ b> A, 30 </ b> B, and 30 </ b> C in the arrangement relationship described above. The housing 42 holds the optical fibers 20A, 20B, and 20C so that the light emission end faces of the optical fibers 20A, 20B, and 20C face the phosphor 30A. The housing 42 preferably has a light shielding property, and prevents the excitation light emitted from the light emitting ends of the optical fibers 20A, 20B, and 20C and the fluorescence emitted from the phosphors 30A, 30B, and 30C from leaking to the outside. Good. More preferably, the inner surface of the housing 42 is formed of a reflection surface, and reflects the excitation light emitted from the light emission ends of the optical fibers 20A, 20B, and 20C and the fluorescence emitted from the phosphors 30A, 30B, and 30C. Good. This reduces light loss.

<Operation>
The operation of the light source device of this embodiment will be described.

  Returning to FIG. 1, the description will be continued. The excitation light sources 10A, 10B, and 10C are connected to a drive circuit (not shown) and are turned on and off independently.

  When the excitation light source 10A for exciting the phosphor 30A is turned on, excitation light is emitted from the excitation light source 10A. Excitation light emitted from the excitation light source 10A is guided to the wavelength conversion unit 40 by the optical fiber 20A, and emitted from the light emission end of the optical fiber 20A toward the phosphor 30A. Since the light emission end of the optical fiber 20A is arranged at a distance from the phosphor 30A, the excitation light emitted from the optical fiber 20A spreads at an emission angle corresponding to the NA of the optical fiber 20A and is irradiated to the phosphor 30A. All or part of the excitation light irradiated to the phosphor 30A excites the phosphor 30A, and the phosphor 30A emits red fluorescence almost uniformly in all directions. The phosphors 30B and 30C transmit part of the red fluorescence emitted from the phosphor 30A, but absorb or scatter the remaining part. This reduces the red fluorescence emitted from the light exit end of the wavelength conversion unit 40. However, since the phosphors 30B and 30C have through holes 32 and 34 for transmitting red fluorescence emitted from the phosphor 30A, respectively, the phosphors 30B and 30C extend from the phosphor 30A toward the light emission end of the wavelength conversion unit 40. Part of the emitted red fluorescence passes through the through holes 32 and 34 of the phosphors 30B and 30C, and is emitted as it is from the light exit end of the wavelength conversion unit 40 without being absorbed or scattered.

  When the excitation light source 10B for exciting the phosphor 30B is turned on, excitation light is emitted from the excitation light source 10B. Excitation light emitted from the excitation light source 10B is guided to the wavelength conversion unit 40 by the optical fiber 20B, and emitted from the light emission end of the optical fiber 20B toward the phosphor 30A. The excitation light emitted from the optical fiber 20B passes through the phosphor 30A and is irradiated to the phosphor 30B. All or a part of the excitation light applied to the phosphor 30B excites the phosphor 30B, and the phosphor 30B emits green fluorescence almost uniformly in all directions. The phosphor 30C transmits part of the green fluorescence emitted from the phosphor 30B, but absorbs or scatters the remaining part. This reduces the green fluorescence emitted from the light exit end of the wavelength conversion unit 40. However, since the phosphor 30C has the through hole 36 for transmitting the green fluorescence emitted from the phosphor 30B, the green light emitted from the phosphor 30B toward the light emission end of the wavelength conversion unit 40 is displayed. A part of the fluorescence passes through the through hole 36 of the phosphor 30C and is emitted from the light exit end of the wavelength conversion unit 40 as it is without being absorbed or scattered.

  When the excitation light source 10C for exciting the phosphor 30C is turned on, excitation light is emitted from the excitation light source 10C. Excitation light emitted from the excitation light source 10C is guided to the wavelength conversion unit 40 by the optical fiber 20C, and emitted from the light emission end of the optical fiber 20C toward the phosphor 30A. Excitation light emitted from the optical fiber 20C passes through the phosphors 30A and 30B and is irradiated to the phosphor 30C. All or part of the excitation light irradiated to the phosphor 30C excites the phosphor 30C, and the phosphor 30C emits blue fluorescence almost uniformly in all directions. Blue fluorescence emitted from the phosphor 30 </ b> C toward the light emission end of the wavelength conversion unit 40 is emitted from the light emission end of the wavelength conversion unit 40.

  In the wavelength conversion unit 40 shown in FIG. 6, the excitation light for exciting the phosphor 30B passes through the through holes 32 and 34 for transmitting the red fluorescence and the excitation for exciting the phosphor 30C. There is a concern that light is emitted through the through hole 36 for transmitting green fluorescence. A preferred configuration of the wavelength conversion unit 40 that avoids this is shown in FIG. The wavelength conversion unit 40 includes an excitation light blocking filter 50 disposed on the light emission end side of the wavelength conversion unit 40 with respect to the phosphor 30C.

  The excitation light shielding filter 50 has a characteristic of transmitting fluorescence emitted from the phosphors 30A, 30B, and 30C and shielding at least excitation light that excites the phosphors 30B and 30C. Since phosphor 30A does not have a through hole, leakage of excitation light for exciting phosphor 30A is small. For this reason, the excitation light shielding filter 50 does not necessarily need to have the characteristic of shielding the excitation light that excites the phosphor 30A. However, it is preferable that the excitation light blocking filter 50 further has a characteristic of blocking excitation light that excites the phosphor 30A.

<Action>
When the excitation light sources 10A, 10B, and 10C are sequentially turned on and off at a predetermined timing, the light source device of the present embodiment emits red fluorescence, green fluorescence, and blue fluorescence as illumination light at a desired timing. When two of the excitation light sources 10A, 10B, and 10C are turned on at the same time, light having a desired color tone in which two of the corresponding red fluorescence, green fluorescence, and blue fluorescence are mixed is used as illumination light. Inject as. Further, when all of the excitation light sources 10A, 10B, and 10C are turned on simultaneously, white light in which red fluorescence, green fluorescence, and blue fluorescence are mixed is emitted as illumination light. In addition, the emission intensity of each excitation light source 10A, 10B, 10C is adjusted by the drive current, or the length of time for which each excitation light source 10A, 10B, 10C is turned on is adjusted, thereby red fluorescence. It is possible to adjust the color temperature of white light in which green fluorescence and blue fluorescence are mixed.

  In the present embodiment, the red fluorescence emitted from the phosphor 30A to the light emission end side of the wavelength conversion unit 40 is emitted through the through holes 32 and 34 of the phosphors 30B and 30C. The amount of light absorbed or scattered by the bodies 30B and 30C is reduced. Further, since the green fluorescence emitted from the phosphor 30B to the light emitting end side of the wavelength conversion unit 40 is emitted through the through hole 34 of the phosphor 30C, the green fluorescence is absorbed or scattered by the phosphor 30C. The amount of light emitted is reduced. As a result, brighter illumination light can be obtained.

  Further, as shown in FIGS. 4 and 5, the through hole 32 is rotationally symmetrical with respect to the rotationally symmetric axis of the phosphor 30B, and the through holes 34 and 36 are rotationally symmetric axes of the phosphor 30C. Therefore, the influence of the through holes 32, 34, and 36 on the light distribution is reduced. For example, when the phosphor 30B is irradiated with excitation light, fluorescence having a distribution corresponding to the intensity of the excitation light is emitted from the portion of the phosphor 30B excluding the through hole 32, and no fluorescence is emitted from the through hole 32. . For this reason, the through hole 32 becomes a dark spot. However, the through hole 32 is arranged rotationally symmetrically with respect to the rotationally symmetric axis of the phosphor 30B, and the center of gravity of the green fluorescent light overlaps the rotationally symmetric axis of the fluorescent body 30B. It is suppressed well. The same can be said for the blue fluorescence emitted from the phosphor 30C.

  As can be seen from the above description, since the light source device of the present embodiment has a simple configuration, it can be easily configured in a small size, can switch colors, and emits bright illumination light.

[Second Embodiment]
<Configuration>
Next, a second embodiment of the present invention will be described with reference to FIGS. In the following, portions common to the first embodiment are omitted, and only different portions are described.

  The appearance of the light source device of this embodiment is configured in the same manner as the light source device of the first embodiment shown in FIG. 1, and the internal structure of the wavelength conversion unit 40 is different from that of the first embodiment. The phosphor in the wavelength conversion unit 40 according to the present embodiment is shown in FIGS.

  In the present embodiment, as shown in FIGS. 8 and 10, the wavelength conversion unit 40 includes three phosphors 30D, 30E, and 30F. The phosphors 30D, 30E, and 30F have the same optical characteristics as the phosphors 30A, 30B, and 30C of the first embodiment, respectively. The phosphors 30D, 30E, and 30F are arranged side by side in the light emitting end direction. The phosphor 30E is located closer to the light emission end than the phosphor 30D, and the phosphor 30F is located closer to the light emission end than the phosphor 30E.

  As shown in FIG. 9, each of the phosphors 30D, 30E, and 30F has a rotationally symmetric outline in projection onto a plane perpendicular to the light exit end direction. For example, each of the phosphors 30D, 30E, and 30F has a disk shape, and has a circular outline when projected onto a plane perpendicular to the light emitting end direction. In projection onto a plane perpendicular to the light exit end direction, the contour of the phosphor 30E is smaller than the contour of the phosphor 30D, and the contour of the phosphor 30F is smaller than the contour of the phosphor 30E. Furthermore, the outline of the phosphor 30E is located inside the outline of the phosphor 30D, and the outline of the phosphor 30F is located inside the outline of the phosphor 30E. The phosphors 30D, 30E, and 30F are arranged such that the centers of their circular contours coincide with each other.

  As shown in FIG. 10, the phosphors 30D, 30E, and 30F are held in the casing 42 in the arrangement relationship described above. The phosphors 30E and 30F are attached to the housing 42 via transparent members 60E and 60F, respectively. The housing 42 holds the optical fibers 20A, 20B, and 20C so that the light emission end faces of the optical fibers 20A, 20B, and 20C face the phosphor 30D. As described in the first embodiment, the housing 42 preferably has a light shielding property, and more preferably, the inner surface is formed of a reflective surface.

<Operation>
The operation of the light source device of this embodiment will be described. Since the basic operation is the same as that of the light source device of the first embodiment, only different parts will be described here.

  When the excitation light source 10A for exciting the phosphor 30D is turned on, excitation light is emitted from the optical fiber 20A and applied to the phosphor 30D, and red fluorescence is emitted from the phosphor 30D. The red fluorescence emitted from the phosphor 30D toward the light exit end passes through the transparent member 60E, part of the light enters the phosphor 30E, and the other part passes outside the phosphor 30E. The red fluorescence incident on the phosphor 30E is absorbed or scattered by the phosphor 30E, and a part of the red fluorescence further enters the phosphor 30F and is absorbed or scattered by the phosphor 30F. The red fluorescence that has passed through the outside of the phosphor 30E passes through the transparent member 60E, and is emitted from the light exit end of the wavelength conversion unit 40 as it is without being absorbed or scattered.

  When the excitation light source 10B for exciting the phosphor 30E is turned on, excitation light is emitted from the optical fiber 20B, transmitted through the phosphor 30D, and irradiated to the phosphor 30E, and green fluorescence is emitted from the phosphor 30E. . The green fluorescence emitted from the phosphor 30E toward the light exit end passes through the transparent member 60F, a part thereof enters the phosphor 30F, and the other part passes outside the phosphor 30F. The green fluorescence incident on the phosphor 30F is absorbed or scattered by the phosphor 30F. The green fluorescence that has passed through the outside of the phosphor 30F is emitted as it is from the light exit end of the wavelength conversion unit 40 without being absorbed or scattered.

  When the excitation light source 10C for exciting the phosphor 30F is turned on, excitation light is emitted from the optical fiber 20C, transmitted through the phosphors 30D and 30E, and irradiated to the phosphor 30F, and blue light fluorescence is emitted from the phosphor 30F. Is emitted. Blue fluorescence emitted from the phosphor 30 </ b> F toward the light emission end is emitted from the light emission end of the wavelength conversion unit 40.

<Action>
In the present embodiment, since the contours of the phosphors 30E and 30F are located inside the contour of the phosphor 30D in the projection onto the plane perpendicular to the light emitting end direction, the phosphors 30D are emitted in the light emitting end direction. Some of the red fluorescence is absorbed or scattered by the phosphors 30E and 30F, but the portion passing through the outside of the phosphor 30E is emitted as it is from the light exit end of the wavelength conversion unit 40. As a result, the amount of red fluorescent light absorbed or scattered by the phosphors 30E and 30F is reduced. Further, since the contour of the phosphor 30F is located inside the contour of the phosphor 30E in the projection onto the plane perpendicular to the light exit end direction, the green fluorescence emitted from the phosphor 30E in the light exit end direction is Some of the light is absorbed or scattered by the phosphor 30F, but the portion that passes outside the phosphor 30F is directly emitted from the light exit end of the wavelength conversion unit 40. Thereby, the light quantity by which the green fluorescence is absorbed or scattered by the phosphor 30F is reduced. As a result, brighter illumination light can be obtained.

  Further, since the phosphors 30D, 30E, and 30F do not have through holes, unlike the phosphors 30B and 30C of the first embodiment, the fluorescence emitted from the phosphors 30D, 30E, and 30F does not generate a dark spot. . For this reason, more stable light distribution is achieved. Further, the phosphors 30D, 30E, and 30F do not need to be provided with a through hole as compared with the phosphors 30B and 30C of the first embodiment, and thus are easy to manufacture and advantageous in terms of cost.

[Third embodiment]
<Configuration>
Next, a third embodiment of the present invention will be described with reference to FIG. In the following, portions common to the first embodiment are omitted, and only different portions are described.

  The appearance of the light source device of this embodiment is configured in the same manner as the light source device of the first embodiment shown in FIG. 1, and the internal structure of the wavelength conversion unit 40 is different from that of the first embodiment. The internal structure of the wavelength conversion unit 40 according to this embodiment is shown in FIG.

  In the present embodiment, as shown in FIG. 11, the wavelength conversion unit 40 includes two filters 70A and 70B in addition to the phosphors 30A, 30B, and 30C. The filter 70A is disposed between the phosphor 30A and the phosphor 30B. The filter 70B is disposed between the phosphor 30B and the phosphor 30C.

  The filter 70A transmits red fluorescence emitted from the phosphor 30A, excitation light that excites the phosphor 30B, and excitation light that excites the phosphor 30C, and shields green fluorescence emitted from the phosphor 30B. have. More preferably, the filter 70A has a characteristic of reflecting green fluorescence. For example, the filter 70A is configured by an optical filter that transmits light in a red / orange region having a wavelength of 580 nm or longer and reflects light having a wavelength shorter than that. The filter 70B transmits red fluorescence emitted from the phosphor 30A, green fluorescence emitted from the phosphor 30B, and excitation light that excites the phosphor 30C, and blue fluorescence emitted from the phosphor 30C. It has the property of shielding light. More preferably, the filter 70B has a characteristic of reflecting blue fluorescence. For example, the filter 70B is an optical filter that transmits light in the green / red region having a wavelength of 500 nm or more and reflects light having a wavelength shorter than that.

<Operation>
The operation of the light source device of this embodiment will be described. Since the basic operation is the same as that of the light source device of the first embodiment, only different parts will be described here.

  When the excitation light source 10A for exciting the phosphor 30A is turned on, red fluorescence is emitted from the phosphor 30A. Since both the filters 70A and 70B transmit red fluorescence, a part of the red fluorescence emitted from the phosphor 30A toward the light emission end passes through the filter 70A and passes through the through hole 32 of the phosphor 30B. The light passes through the filter 70B, passes through the through holes 32 and 34 of the phosphors 30B and 30C, and is emitted from the light exit end of the wavelength conversion unit 40 without being absorbed or scattered.

  When the excitation light source 10B for exciting the phosphor 30B is turned on, green fluorescence is emitted from the phosphor 30B. Since the filter 70B transmits green fluorescence, a part of the green fluorescence emitted from the phosphor 30B toward the light exit end passes through the filter 70B and is absorbed or scattered through the through hole 36 of the phosphor 30C. The light is emitted from the light exit end of the wavelength conversion unit 40 without being emitted. Further, when the filter 70A has a characteristic of reflecting green fluorescence, the green fluorescence emitted from the phosphor 30B toward the light source side is reflected by the filter 70A toward the light emission end side. Part of the green fluorescence reflected by the filter 70A passes through the phosphor 30B and the filter 70B, passes through the through hole 36 of the phosphor 30C, and is not absorbed or scattered, so that the light of the wavelength conversion unit 40 is emitted. It is injected from the injection end.

  When the excitation light source 10C for exciting the phosphor 30C is turned on, blue light fluorescence is emitted from the phosphor 30C. Blue fluorescence emitted from the phosphor 30 </ b> C toward the light emission end is emitted from the light emission end of the wavelength conversion unit 40. Further, when the filter 70B has a characteristic of reflecting blue fluorescence, the green fluorescence emitted from the phosphor 30C toward the light source side is reflected by the filter 70B toward the light emission end side. Part of the green fluorescence reflected by the filter 70B passes through the phosphor 30C and is emitted from the light exit end of the wavelength conversion unit 40.

<Action>
In general, a phosphor is excited by light shorter than its own emission wavelength. Therefore, depending on the fluorescent material, the phosphor 30A is excited by green fluorescence emitted from the phosphor 30B or blue fluorescence emitted from the phosphor 30C, and emits red fluorescence although not desired. May end up. For example, when the excitation light source 10B is turned on, green fluorescence emitted from the phosphor 30B in the direction of the phosphor 30A excites the phosphor 30A, and red fluorescence is emitted from the phosphor 30A. there is a possibility. As a result, the intention is to emit green illumination light, but actually, illumination light of an undesired color in which green and red are mixed is emitted. However, in the light source device of the present embodiment, since the filter 70A for shielding green fluorescence is disposed between the phosphor 30A and the phosphor 30B, the green light emitted from the phosphor 30B toward the phosphor 30A is disposed. The fluorescence is shielded by the filter 70A and cannot reach the phosphor 30A. For this reason, the phosphor 30A is not excited undesirably, and when the excitation light source 10B is turned on, the light source device emits only green fluorescence as illumination light.

  Similarly, when the excitation light source 10C of the phosphor 30A is turned on, the blue fluorescence emitted from the phosphor 30C in the direction of the phosphor 30B is blocked by the filter 70B and cannot reach the phosphor 30B. The phosphor 30B is not excited undesirably, and the light source device emits only blue fluorescence as illumination light.

  Therefore, the light source device of this embodiment has the same advantages as the light source device of the first embodiment, and emits illumination light with improved red, green, and blue purity as compared to the light source device of the first embodiment. .

  In particular, when the filter 70 </ b> A has a characteristic of reflecting green fluorescence, the green fluorescence emitted from the phosphor 30 </ b> B is efficiently emitted from the wavelength conversion unit 40. Further, when the filter 70B has a characteristic of reflecting blue fluorescence, the blue fluorescence emitted from the phosphor 30C is efficiently emitted from the wavelength conversion unit 40.

  For this reason, the light source device of the present embodiment emits bright illumination light with higher use efficiency of fluorescence than the light source device of the first embodiment.

<Modification of Third Embodiment>
The wavelength conversion unit 40 shown in FIG. 11 has a configuration in which filters 70A and 70B are added to the wavelength conversion unit 40 of the first embodiment, but the wavelength conversion unit 40 of this embodiment is the same as that of the second embodiment. The structure which added filter 70A, 70B with respect to the wavelength conversion unit 40 may be sufficient. As a modification of this embodiment, a configuration in which filters 70A and 70B are added to the wavelength conversion unit 40 of the second embodiment is shown in FIG. As shown in FIG. 12, in the wavelength conversion unit 40 of this modification, the filter 70A is disposed between the phosphor 30D and the phosphor 30E. The filter 70B is disposed between the phosphor 30E and the phosphor 30F. The filter 70A may also serve as the transparent member 60E to which the phosphor 30E is fixed. Similarly, the filter 70B may also serve as the transparent member 60F to which the phosphor 30F is fixed.

  When the excitation light source 10A for exciting the phosphor 30A is turned on, red fluorescence is emitted from the phosphor 30D. Part of red fluorescence emitted from the phosphor 30D toward the light exit end passes through the filter 70A, passes through the outside of the phosphor 30E, passes through the filter 70B, and is not absorbed or scattered. The light is emitted from the light exit end of the wavelength conversion unit 40.

  When the excitation light source 10B for exciting the phosphor 30E is turned on, green fluorescence is emitted from the phosphor 30E. A part of green fluorescence emitted from the phosphor 30E toward the light emission end passes through the filter 70B, passes through the outside of the phosphor 30F, and is not absorbed or scattered, so that the light emission of the wavelength conversion unit 40 is performed. Ejected from the end. Further, when the filter 70A has a characteristic of reflecting green fluorescence, the green fluorescence emitted from the phosphor 30E toward the light source side is reflected by the filter 70A toward the light emission end side. A part of the green fluorescence reflected by the filter 70A passes through the phosphor 30E and the filter 70B, passes through the outside of the phosphor 30F, and is not absorbed or scattered. Is injected from.

  Other operations and actions are the same as those of the wavelength conversion unit 40 shown in FIG.

[Fourth embodiment]
<Configuration>
Next, a fourth embodiment of the present invention will be described with reference to FIG. In the following, portions common to the first embodiment are omitted, and only different portions are described.

  The appearance of the light source device of this embodiment is configured in the same manner as the light source device of the first embodiment shown in FIG. 1, and the internal structure of the wavelength conversion unit 40 is different from that of the first embodiment. The internal structure of the wavelength conversion unit 40 according to this embodiment is shown in FIG.

  In this embodiment, as shown in FIG. 13, the wavelength conversion unit 40 extends through the through hole 32 of the phosphor 30B and the through hole 34 of the phosphor 30C in addition to the phosphors 30A, 30B, and 30C. A light guide path 80A and a light guide path 80B extending through the through hole 36 of the phosphor 30C are provided. The end surface on the light source side of the light guide path 80A is in contact with the phosphor 30B. The end surface of the light guide path 80B on the light source side is in contact with the phosphor 30B. The light guide 80A guides red fluorescence emitted from the phosphor 30A. The light guide 80B guides green fluorescence emitted from the phosphor 30B. The light guide paths 80A and 80B are not limited to this, but are constituted by, for example, optical fibers having a core = cladding structure.

<Action>
In the present embodiment, red fluorescence emitted from the phosphor 30 </ b> A and incident on the light guide path 80 </ b> A is efficiently guided by the light guide path 80 </ b> A and emitted from the light exit end of the wavelength conversion unit 40. Similarly, the green fluorescence emitted from the phosphor 30B and incident on the light guide path 80B is efficiently guided by the light guide path 80B and emitted from the light exit end of the wavelength conversion unit 40. Thereby, brighter illumination light can be obtained. Furthermore, when the light guides 80A and 80B are configured by optical fibers having a core = cladding structure, the phosphors 30A, 30B, and 30C are far apart, or the casing 42 of the wavelength conversion unit 40 is deformed. The loss of red fluorescence and green fluorescence is kept low.

<Modifications of First Embodiment to Fourth Embodiment>
In the first embodiment, the third embodiment, and the fourth embodiment, the phosphors 30A, 30B, and 30C are arranged at intervals in the light emitting end direction, but as shown in FIG. 30B and 30C may be arranged in contact with each other. Further, in the second embodiment and the third embodiment, the phosphors 30D, 30E, and 30F are arranged at intervals in the light emission end direction. However, as shown in FIG. 15, the phosphors 30D, 30E, and 30F. May be arranged in contact with each other. By adopting such a configuration, the wavelength conversion unit 40 can be reduced in size. In addition, the red fluorescence emitted from the phosphor 30 </ b> A and the green fluorescence emitted from the phosphor 30 </ b> B can be easily guided to the light exit end of the wavelength conversion unit 40.

[Fifth embodiment]
<Configuration>
A fifth embodiment of the present invention will be described with reference to FIG. In the following, portions common to the first embodiment are omitted, and only different portions are described.

  A light source device according to a fifth embodiment of the present invention is shown in FIG. In the present embodiment, as shown in FIG. 16, the light source device has red fluorescence and green fluorescence emitted from the wavelength conversion unit 40 in addition to the configuration of the light source device of the first embodiment shown in FIG. 1. And a light guide portion for guiding illumination light including blue fluorescence. The light guide part is composed of a bundle fiber 90. The bundle fiber 90 is connected to the light emission end side of the wavelength conversion unit 40, guides the illumination light emitted from the wavelength conversion unit 40, and emits it from the light emission end of the bundle fiber 90. Since the bundle fiber 90 receives and guides the fluorescence emitted from the wavelength conversion unit 40, it is desirable that the bundle fiber 90 has a large NA.

<Operation>
The operation of the light source device of the present embodiment is the same as that of the light source device of the first embodiment until the fluorescence emitted from the phosphors 30A, 30B, 30C is emitted from the wavelength conversion unit 40. In the present embodiment, the fluorescence emitted from the wavelength conversion unit 40 within the NA range of the bundle fiber 90 enters the bundle fiber 90, is guided by the bundle fiber 90, and is emitted from the light emission end of the bundle fiber 90. .

<Action>
In the present embodiment, the light emission end of the light source device is downsized as compared with the light source devices of the first embodiment and the second embodiment in which the wavelength conversion unit 40 is disposed at the light emission end of the light source device. Furthermore, although the phosphors 30A to 30C generate heat when emitting fluorescence, in the light source device of the present embodiment, the phosphors 30A to 30C are relatively far from the light emitting end of the light source device, and thus the light emission of the light source device. Heat generation near the edges is suppressed. This is useful for applications that are incorporated into endoscopes.

  Here, an example in which the light guide unit that guides the illumination light emitted from the wavelength conversion unit 40 is configured by the bundle fiber 90 is shown, but the present invention is not limited to this, and a multimode single fiber having a large NA. Or a light guide having a core = cladding structure. A single fiber is suitable when the light guide is particularly small.

  In addition, the example in which the bundle fiber 90 and the wavelength conversion unit 40 are directly connected has been shown. However, the present invention is not limited to this, and for example, the bundle fiber 90 and the wavelength conversion unit 40 are connected via an optical element such as a lens or a reflector. It may be connected.

  Furthermore, the wavelength conversion unit 40 is not limited to the configuration of the first embodiment, but may be the configuration of the second embodiment to the fourth embodiment.

<Modification of Fifth Embodiment>
A modification of the fifth embodiment of the present invention is shown in FIG. As shown in FIG. 17, in the light source device of the present modification, the light guide unit that guides the illumination light emitted from the wavelength conversion unit 40 is a bundle fiber 92 instead of the bundle fiber 90 shown in FIG. 16. It is configured. The bundle fiber 92 is branched into two on the way, and has two light exit ends 94.

  Since the light source device of this modification has the two light emission ends 94, it has the advantage that it is difficult to cause shadows on the object to be illuminated.

<Modification of First Embodiment to Fifth Embodiment>
Each of the light source devices of the embodiments described so far includes three excitation light sources 10A, 10B, and 10C, three optical fibers 20A, 20B, and 20C, and three phosphors 30A, 30B, 30C, or 30D, 30E, and 30F. However, the configuration may include two excitation light sources 10A and 10B, two optical fibers 20A and 20B, and two phosphors 30A and 30B or 30D and 30E. For example, a configuration in which the excitation light source 10C, the optical fiber 20C, and the phosphor 30C are omitted from the light source device shown in FIG. 1, FIG. 16, or FIG. Further, a configuration in which the optical fiber 20C and the phosphor 30C are omitted from the wavelength conversion unit 40 illustrated in FIG. 7, a configuration in which the phosphor 30C and the transparent member 60F are omitted from the wavelength conversion unit 40 illustrated in FIG. 10, and a configuration illustrated in FIG. The configuration in which the phosphor 30C and the filter 70B are omitted from the wavelength conversion unit 40, the configuration in which the phosphor 30F and the filter 70B are omitted from the wavelength conversion unit 40 shown in FIG. 12, and the phosphor from the wavelength conversion unit 40 shown in FIG. The configuration may be such that 30C and the light guide path 80B are omitted.

  In such a configuration, for example, in the combination of the phosphors 30A, 30B or 30D, 30F, the fluorescence emitted from the phosphors 30A or 30D and the fluorescence emitted from the phosphors 30B or 30F are complementary to each other. For example, the relationship between blue and yellow or blue green and red is selected. In this case, when the phosphors 30A, 30B or 30D, 30F are excited together, the light source device emits white illumination light.

  Since the light source device of this modification has only two phosphors 30A, 30B or 30D, 30F, there are a wide variety of combinations of phosphors 30A, 30B or 30D, 30F that satisfy the required characteristics.

<Mounting the light source device to the endoscope device>
In addition, the light source device of the above-described embodiment is particularly suitable for mounting on an endoscope apparatus.

  A general endoscope apparatus is schematically shown in FIG. As shown in FIG. 18, the endoscope apparatus 100 includes an operation unit 110, an insertion unit 120 extending from the operation unit 110, and an endoscope distal end unit 130 positioned at the distal end of the insertion unit 120. Yes.

  Further, FIG. 19 shows a configuration of a general endoscope distal end portion 130. As shown in FIG. 19, the endoscope distal end portion 130 includes three distal end metal members 132A, 132B, and 132C and a cover 144 that covers them. The two tip metal members 132A and 132C are coupled via a heat insulating material 134A, and the two tip metal members 132B and 132C are coupled via a heat insulating material 134B. A solid-state imaging device 136, an air / water supply nozzle 138, and a suction channel 140 are provided on the distal end metal member 132C. Further, one light guide unit 142 for illumination is provided on each of the front end metal members 132A and 132B.

  Thus, the endoscope apparatus generally has two light guide units 142. For this reason, when the light source device of the above-described embodiment is mounted on an endoscope device, as shown in FIG. 1 or FIG. 9, two light source devices having one light emitting unit may be incorporated in the endoscope device. Alternatively, as shown in FIG. 12, only one light source device having two light emitting portions may be incorporated in the endoscope device.

  The configuration incorporating the light source device shown in FIG. 1 is convenient for obtaining illumination light with high luminance. The configuration incorporating the light source device shown in FIG. 9 or FIG. 12 is to suppress the heat generation in the vicinity of the distal end portion of the endoscope because the wavelength converting unit 40 that generates heat is disposed away from the distal end portion of the endoscope. convenient.

  The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to these embodiments, and various modifications and changes can be made without departing from the scope of the present invention. Also good.

  In all the embodiments described above, the light source is configured by a semiconductor laser, but the light source is not limited to this, and may be configured by another semiconductor light source such as a light emitting diode. When a light emitting diode is used, a cheaper light source device can be obtained as compared with the case where a semiconductor laser is used.

  In the first embodiment, the example in which the optical apertures of the phosphors 30B and 30C that transmit the fluorescence emitted from the phosphors 30A and 30B are each constituted by a plurality of through holes has been described. 30B and 30C may be replaced with phosphors 30G and 30H having single through holes 33 and 35, respectively, as shown in FIG.

1 shows a light source device according to a first embodiment of the present invention. The phosphor shown in FIG. 1 is shown. It is the figure which looked at the fluorescent substance by the side of the light source shown in FIG. 1 from the light emission end direction. It is the figure which looked at the center fluorescent substance shown in FIG. 1 from the light emission end direction. It is the figure which looked at the fluorescent substance of the light emission end side shown in FIG. 1 from the light emission end direction. The wavelength conversion unit shown in FIG. 1 is shown. 7 shows another wavelength conversion unit that replaces the wavelength conversion unit shown in FIG. 6. The wavelength conversion unit by 2nd embodiment of this invention is shown. It is the figure which looked at the fluorescent substance shown in FIG. 8 from the light emission end direction. The wavelength conversion unit shown in FIG. 1 is shown. 7 shows a wavelength conversion unit according to a third embodiment of the present invention. The modification of 3rd embodiment of this invention is shown. 10 shows a wavelength conversion unit according to a fourth embodiment of the present invention. The modification of 1st embodiment, 3rd embodiment, and 4th embodiment is shown. The modification of 2nd embodiment and 3rd embodiment is shown. 10 shows a light source device according to a fifth embodiment. The modification of 5th embodiment is shown. 1 schematically shows a general endoscope apparatus. The structure of the endoscope front-end | tip part shown in FIG. 18 is shown. The modification of 1st embodiment is shown.

Explanation of symbols

10A, 10B, 10C: Excitation light source, 12A, 12B, 12C ... Semiconductor laser, 14A, 14B, 14C ... Lens, 20A, 20B, 20C ... Optical fiber, 22A, 22B, 22C ... Light exit end, 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H ... phosphor, 32, 34, 36 ... through hole, 40 ... wavelength conversion unit, 40 ... wavelength conversion unit, 42 ... housing, 50 ... excitation light shielding filter, 60E, 60F ... Transparent member, 70A, 70B, 70C ... Filter, 80A, 80B ... Light guide, 90, 92 ... Bundle fiber, 94 ... Light exit end, 100 ... Endoscope device, 110 ... Operation unit, 120 ... Insertion unit, 130 ... End of endoscope, 132A, 132B, 132C ... tip metal member, 134A, 134B ... heat insulating material, 136 ... individual imaging device, 38 ... air and water supply nozzle, 140 ... suction channel, 142 ... light guide unit, 144 ... cover.

Claims (22)

A first light source that emits first excitation light;
A second light source that emits second excitation light;
A first optical fiber for guiding the first excitation light emitted from the first light source;
A second optical fiber for guiding the second excitation light emitted from the second light source;
A first phosphor that emits first fluorescence when excited by the first excitation light emitted from the first optical fiber;
A second phosphor that is excited by the second excitation light emitted from the second optical fiber and emits a second fluorescence different from the first fluorescence,
The first phosphor and the second phosphor are arranged side by side in the light emitting end direction, and the second phosphor is located closer to the light emitting end than the first phosphor, The light emitting end faces of the first and second optical fibers are opposed to the first phosphor, the first phosphor transmits the second excitation light, and the second phosphor is the first phosphor. A light source device having a first optical aperture that transmits the fluorescence of the light source. A third light source that emits third excitation light;
A third optical fiber for guiding the third excitation light emitted from the third light source;
A third phosphor that emits third fluorescence that is excited by the third excitation light emitted from the third optical fiber and that is different from any of the first and second fluorescence;
The first phosphor, the second phosphor, and the third phosphor are arranged side by side in the light emitting end direction, and the third phosphor is closer to the light emitting end side than the second phosphor. The light emitting end faces of the first, second and third optical fibers are opposed to the first phosphor, and the first phosphor emits the second and third excitation lights. The second phosphor transmits the third excitation light, the third phosphor has a second optical aperture that transmits the first and second fluorescence, The light source device according to claim 1.   The light source device according to claim 2, wherein the first optical aperture partially overlaps the second optical aperture in projection onto a plane perpendicular to the light emitting end direction.   The first optical aperture includes a plurality of first through holes formed in the second phosphor, and the second optical aperture includes a plurality of holes formed in the third phosphor. The second through hole and a plurality of third through holes formed in the third phosphor, wherein the first through hole and the second through hole are aligned. 4. The light source device according to 3.   2. The light source device according to claim 1, wherein the first optical opening is configured by a through hole formed in the second phosphor.   In projection onto a plane perpendicular to the light exit end direction, the first, second, and third phosphors each have a rotationally symmetric outline, and the first, second, and third through holes are respectively The light source device according to claim 4, wherein the light source device is arranged rotationally symmetric with respect to a rotationally symmetric axis.   In the projection onto the plane perpendicular to the light exit end direction, the first and second phosphors each have a rotationally symmetric outline, and the first through hole is rotationally symmetric with respect to a rotationally symmetric axis. The light source device according to claim 5, wherein the light source device is arranged.   A first light guide for guiding the first fluorescence extending through the first through hole and the second through hole; and the second extending through the third through hole. The light source device according to claim 6, further comprising a second light guide for guiding the fluorescence of the light.   The light source device according to claim 7, further comprising a light guide that guides the first fluorescence extending through the first through hole. A first light source that emits first excitation light;
A second light source that emits second excitation light;
A first optical fiber for guiding the first excitation light emitted from the first light source;
A second optical fiber for guiding the second excitation light emitted from the second light source;
A first phosphor that emits first fluorescence when excited by the first excitation light emitted from the first optical fiber;
A second phosphor that is excited by the second excitation light emitted from the second optical fiber and emits a second fluorescence different from the first fluorescence,
The first phosphor and the second phosphor are arranged side by side in the light emitting end direction, and the second phosphor is located closer to the light emitting end than the first phosphor, The light emission end faces of the first and second optical fibers are opposed to the first phosphor, and the first phosphor transmits the second excitation light to a plane perpendicular to the light emission end direction. The light source device in which the contour of the second phosphor is smaller than the contour of the first phosphor in the projection. A third light source that emits third excitation light;
A third optical fiber for guiding the third excitation light emitted from the third light source;
A third phosphor that emits third fluorescence that is excited by the third excitation light emitted from the third optical fiber and that is different from any of the first and second fluorescence;
The first phosphor, the second phosphor, and the third phosphor are arranged side by side in the light emitting end direction, and the third phosphor is closer to the light emitting end side than the second phosphor. The light emitting end faces of the first, second and third optical fibers are opposed to the first phosphor, and the first phosphor emits the second and third excitation lights. The second phosphor transmits the third excitation light, and the contour of the third phosphor is the contour of the second phosphor in the projection onto the plane perpendicular to the light exit end direction. The light source device according to claim 10, which is smaller than the light source device.   In projection onto a plane perpendicular to the light emitting end direction, the contour of the second phosphor is positioned inside the contour of the first phosphor, and the contour of the third phosphor is the second phosphor. The light source device according to claim 11, wherein the light source device is located inside a contour of the phosphor.   The light source device according to claim 10, wherein an outline of the second phosphor is located inside an outline of the first phosphor in a projection onto a plane perpendicular to the light emitting end direction. A first filter disposed between the first phosphor and the second phosphor;
A second filter disposed between the second phosphor and the third phosphor;
The first filter has a property of transmitting the first fluorescence and the second and third excitation light and shielding the second fluorescence,
The second filter has a characteristic of transmitting the first and second fluorescence and the second and third excitation lights and shielding the third fluorescence. The light source device according to 1.   The light source device according to claim 14, wherein the first filter has a characteristic of reflecting the second fluorescence, and the second filter has a characteristic of reflecting the third fluorescence. A filter disposed between the first phosphor and the second phosphor;
The light source device according to claim 1, wherein the filter has a characteristic of transmitting the first fluorescence and the second excitation light and shielding the second fluorescence.   The light source device according to claim 16, wherein the filter has a characteristic of reflecting the second fluorescence. An excitation filter disposed on the light emission end side of the third phosphor;
The said excitation filter has a characteristic which permeate | transmits said 1st, 2nd, and 3rd fluorescence, and has shielded said 1st, 2nd, and 3rd excitation light. Light source device. An excitation filter disposed on the light emission end side of the second phosphor;
The light source device according to claim 1, wherein the excitation filter has a characteristic of transmitting the first and second fluorescence and shielding the first and second excitation lights.   The light source device according to claim 2, further comprising an optical light guide that guides light including the first, second, and third fluorescence.   The light source device according to claim 1, further comprising an optical light guide that guides light including the first and second fluorescence.   An endoscope apparatus comprising the light source device according to any one of claims 1 to 20.

Images