Light emitting device

Abstract

To provide a light emitting device capable of improving light extraction efficiency for extracting fluorescent light from excitation light emitted from a light source part.SOLUTION: A light emitting device 1 includes a light source part 2, a fluorescent member 5, a cooling medium 4, a container 3 and a cooling device 6. The fluorescent member 5 converts excitation light C1 from the light source part 2 into fluorescent light C2, and emits the converted fluorescent light C2. The cooling medium 4 cools the fluorescent member 5. The container 3 stores the cooling medium 4 in the inside S1. The cooling device 6 cools the cooling medium 4. The container 3 includes a wall part 31, an incident part 32 and an emission part 33. The wall part 31 partitions the inside S1 and outside of the container 3. The incident part 32 is provided at the wall part 31, and allows the excitation light C1 from the light source part 2 to enter the inside S1 of the container 3. The emission part 33 is provided at the wall part 31, and allows the fluorescent light C2 from the fluorescent member 5 to emit to the outside of the container 3. The fluorescent member 5 is shared with the incident part 32 or the emission part 33.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates generally to light-emitting devices, and more particularly to a light-emitting device in which a fluorescent member that converts excitation light from a light source into fluorescent light is cooled by a cooling medium. [Background technology]

[0002] The light-emitting device described in Patent Document 1 includes a light source (light source unit), a fluorescent member, a cooling medium for cooling the fluorescent member, a container for storing the fluorescent member and the cooling medium, and a cooling device for cooling the cooling medium. In this light-emitting device, excitation light is emitted from the light source. The emitted excitation light enters the inside of the container from an entrance part of the container, propagates through the cooling medium in the container, and enters the fluorescent member. The excitation light that enters the fluorescent member is converted into fluorescence by the fluorescent medium and emitted from the fluorescent member. The emitted fluorescence propagates through the cooling medium in the container and is emitted to the outside of the container from the exit part of the container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-184434 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the light-emitting device described in Patent Document 1, the excitation light from the light source propagates through the cooling medium in the container and enters the fluorescent member, so the cooling medium reduces the efficiency of incidence of the excitation light to the fluorescent member. In addition, the fluorescence from the fluorescent member propagates through the cooling medium in the container and is emitted to the outside of the container, so the cooling medium reduces the efficiency of extracting the fluorescence from the fluorescent member. Thus, in Patent Document 1, attenuation of light (excitation light or fluorescence) occurs due to passing through the cooling medium both during the period from when the excitation light enters the container to when it enters the fluorescent member, and during the period from when the fluorescence is emitted from the fluorescent member to the outside of the container. As a result, the light extraction efficiency of extracting the fluorescence from the excitation light emitted from the light source decreases.

[0005] In view of the above problems, an object of the present disclosure is to provide a light-emitting device capable of improving the light extraction efficiency for extracting fluorescence from excitation light emitted from a light source unit. [Means for solving the problem]

[0006] A light-emitting device according to an aspect of the present disclosure includes a light source unit, a fluorescent member, a cooling medium, a container, and a cooling device. The light source unit emits excitation light. The fluorescent member converts the excitation light from the light source unit into fluorescence and emits the converted fluorescence. The cooling medium cools the fluorescent member. The container contains the cooling medium inside. The cooling device circulates the cooling medium between the container and cools the cooling medium. The container includes a wall unit, an entrance unit, and an exit unit. The container separates the inside and the outside of the container. The entrance unit is provided on the wall unit and causes the excitation light from the light source unit to enter the inside of the container. The exit unit is provided on the wall unit and causes the fluorescence from the fluorescent member to exit the outside of the container. The fluorescent member is used as the entrance unit or the exit unit. Effect of the Invention

[0007] A light-emitting device according to an aspect of the present disclosure has an advantage in that it can improve the light extraction efficiency for extracting fluorescence from excitation light emitted from a light source unit. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the configuration of a light-emitting device according to the first embodiment. [Diagram 2] FIG. 2 is a configuration diagram of a light emitting device according to Modification 1 of Embodiment 1. In FIG. [Diagram 3] FIG. 3 is a configuration diagram of a light emitting device according to Modification 3 of Embodiment 1. In FIG. [Figure 4] FIG. 4 is a configuration diagram of a light emitting device according to the second embodiment. [Diagram 5] FIG. 5 is a configuration diagram of a light emitting device according to Modification 1 of Embodiment 2. In FIG. [Figure 6] FIG. 6 is a configuration diagram of a light emitting device according to Modification 3 of Embodiment 2. In FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, light-emitting devices according to embodiments will be described with reference to the drawings.

[0010] (Embodiment 1) (1) Overview A light-emitting device 1 according to the present embodiment will be described with reference to FIG. 1. As shown in FIG. 1, the light-emitting device 1 includes a light source unit 2, a fluorescent member 5, a cooling medium 4, a container 3, and a cooling device 6. The light source unit 2 emits excitation light C1. The fluorescent member 5 converts the excitation light C1 from the light source unit 2 into fluorescence C2 and emits the converted fluorescence C2. The cooling medium 4 cools the fluorescent member 5. The container 3 accommodates the cooling medium 4 in its interior S1. The cooling device 6 circulates the cooling medium 4 between the container 3 and cools the cooling medium 4. The container 3 includes a wall portion 31, an entrance portion 32, and an exit portion 33. The wall portion 31 separates the interior S1 of the container 3 from the outside. The entrance portion 32 is provided on the wall portion 31 and causes the excitation light C1 from the light source unit 2 to enter the interior S1 of the container 3. The emission section 33 is provided on the wall section 31 and emits the fluorescence C2 from the fluorescent member 5 to the outside of the container 3. The fluorescent member 5 serves as both the incident section 32 and the emission section 33. In the example of FIG.

[0011] According to this configuration, in a configuration in which the fluorescent member 5 also serves as the emission section 33, when the fluorescent light C2 is emitted from the fluorescent member 5 to the outside of the container 3, the fluorescent light C2 does not pass through the cooling medium 4 in the container 3. Therefore, it is possible to reduce a decrease in the light extraction efficiency of the fluorescent light C2 from the fluorescent member 5 due to the cooling medium 4. As a result, it is possible to improve the light extraction efficiency of extracting the fluorescent light C2 from the excitation light C1 emitted from the light source section 2. Furthermore, in a configuration in which the fluorescent member 5 also serves as the incidence section 32, when the excitation light C1 from the light source section 2 is incident on the fluorescent member 5, the excitation light C1 does not pass through the cooling medium 4 in the container 3. Therefore, it is possible to reduce a decrease in the incidence efficiency of the excitation light C1 to the fluorescent member 5 due to the cooling medium 4. As a result, it is possible to improve the light extraction efficiency of extracting the fluorescent light C2 from the excitation light C1 emitted from the light source section 2.

[0012] Moreover, the fluorescent member 5 is provided inside S1 of the wall portion 31 of the container 3 by being used as the entrance portion 32 or the exit portion 33. This reduces the obstruction of the fluorescent member 5 to the flow of the cooling medium 4 inside the container 3. This improves the cooling efficiency of the fluorescent member 5 by the cooling medium 4.

[0013] (2) Detailed explanation 1, the light-emitting device 1 according to the first embodiment is a light-emitting device capable of utilizing, as illumination light, fluorescence C2 emitted from a fluorescent member 5 when excitation light C1 from a light source unit 2 is irradiated onto the fluorescent member 5. The light-emitting device 1 can be used in, for example, a projector, a vehicle headlamp, an endoscope, and the like.

[0014] As shown in FIG. 1, the light emitting device 1 includes a light source unit 2, a container 3, a cooling medium 4, a fluorescent member 5, and a cooling device 6.

[0015] The light source unit 2 emits excitation light C1 including light in a specific wavelength region (for example, a blue wavelength region). The light source unit 2 includes a substrate 21, one or more excitation light sources 22, and a lens 23. The substrate 21 is a member on which the excitation light source 22 is disposed (mounted). The excitation light source 22 is a semiconductor light-emitting element that emits excitation light C1 in a specific wavelength region (for example, a blue wavelength region). The excitation light source 22 is disposed (mounted) on the front surface of the substrate 21. The lens 23 is an optical component for focusing the excitation light C1 from the excitation light source 22 on an incident portion 32 of the container 3, which will be described later. The lens 23 is disposed on the front side of the substrate 21 (i.e., on the front side of the one or more excitation light sources 22).

[0016] The container 3 has an interior S1 that contains a cooling medium 4 that cools the excitation light C1 from the light source unit 2. The container 3 includes a wall unit 31, an entrance unit 32, an exit unit 33, an inlet hole 34, and an outlet hole 35.

[0017] The wall 31 is formed of a material having a light blocking property (for example, a resin or a metal). The wall 31 separates the inside S1 of the container 3 from the outside of the container 3.

[0018] The incident part 32 is provided on the wall part 31, and is a part that allows the excitation light C1 from the light source part 2 to be incident on the inside S1 of the container 3. The incident part 32 is formed of a translucent material (e.g., resin or glass) that can transmit the excitation light C1.

[0019] The emission part 33 is provided on the wall part 31, and is a part that emits the fluorescence C2 emitted from the fluorescent member 5 to the outside of the container 3. The emission part 33 is made of a translucent member (e.g., resin or glass) that can transmit the fluorescence C2. In the first embodiment, the emission part 33 also serves as the fluorescent member 5.

[0020] The emission part 33 is provided in the wall part 31 at a position facing the incidence part 32 with the interior S1 of the container 3 interposed therebetween.

[0021] The inlet hole 34 is provided in the wall portion 31, and is a portion through which the cooling medium 4 from the cooling device 6 flows into the interior S1 of the container 3. A first end 7a of the first circulation flow path 7 is connected to the inlet hole 34. The first circulation flow path 7 is a flow path that sends the cooling medium 4 flowing out from the outlet 6a of the cooling device 6 to the inlet hole 34 of the container 3, and connects the inlet hole 34 of the container 3 to the outlet 6a of the cooling device 6.

[0022] The outlet hole 35 is provided in the wall portion 31, and is a portion through which the cooling medium 4 in the container 3 flows out to the outside of the container 3. A first end 8a of the second circulation flow path 8 is connected to the outlet hole 35. The second circulation flow path 8 is a flow path that sends the cooling medium 4 flowing out from the outlet hole 35 of the container 3 to the inlet 6b of the cooling device 6, and connects the outlet hole 35 of the container 3 and the inlet 6b of the cooling device 6.

[0023] The outflow hole 35 is provided in the wall portion 31 at a position facing the inflow hole 34 with the interior S1 of the container 3 interposed therebetween.

[0024] The cooling medium 4 is a medium for cooling the fluorescent member 5. The properties of the cooling medium 4 are preferably, for example, a high boiling point, high thermal conductivity, resistance to metal corrosion, ability to prevent the cooling medium from freezing in winter, resistance to air bubbles, and transparency. As the cooling medium 4, for example, pure water, glycol-based cooling medium, fluorine-based cooling medium, and other cooling mediums can be used. Examples of glycol-based cooling mediums include ethylene glycol and propylene glycol. Examples of fluorine-based cooling mediums include Fluorinert and Galden. Other cooling mediums include silicone oil and antifreeze.

[0025] The fluorescent member 5 is a member that converts the excitation light C1 from the light source unit 2 into fluorescence C2. The fluorescent member 5 contains a phosphor. For example, the fluorescent member 5 is formed by containing a phosphor in a transparent resin. The fluorescent member 5 may be formed of phosphor ceramics (transparent ceramics to which a phosphor is added). The phosphor is a phosphor having a complementary color (e.g., yellow) for converting the excitation light C1 in a specific wavelength range (e.g., blue wavelength range) emitted from the light source unit 2 into white light. The excitation light C1 in a specific wavelength range emitted from the light source unit 2 is converted into white light by hitting the phosphor in the fluorescent member 5. As a result, the fluorescent member 5 emits fluorescence C2, which is white light.

[0026] More specifically, the fluorescent member 5 has a fluorescent layer 51 and a substrate 52 having transparency. The fluorescent layer 51 is a main body of the fluorescent member 5 and is a portion including a phosphor. More specifically, the fluorescent layer 51 is formed by containing a phosphor in a transparent resin. The fluorescent layer 51 is provided on (in contact with) one of the main surfaces on both sides in the thickness direction of the substrate 52. The substrate 52 is a member that supports the fluorescent layer 51. The transparency of the substrate 52 includes translucency that transmits the excitation light C1 and the fluorescence C2. The substrate 52 has a heat dissipation function that dissipates heat generated from the fluorescent layer 51.

[0027] The fluorescent member 5 is formed, for example, in a flat plate shape, and is provided on the wall portion 31 of the container 3 as the emission portion 33. That is, the fluorescent member 5 also serves as the emission portion 33.

[0028] The fluorescent member 5 is disposed such that the substrate 52 faces the interior S1 of the container 3, and the fluorescent layer 51 faces the exterior of the container 3. The outer main surface 5a of the fluorescent member 5 (the outer main surface of the fluorescent layer 51) is flush with the outer main surface of the wall portion 31 (the outer main surface 311a of the first wall portion 311 described later). In other words, the main surface 5a of the two main surfaces in the thickness direction of the fluorescent layer 51 that is not in contact with the substrate 52 is flush with the outer main surface of the wall portion 31. The inner main surface 5b of the fluorescent member 5 (the inner main surface of the substrate 52) is flush with the inner main surface of the wall portion 31 (the inner main surface 311b of the first wall portion 311 described later). In other words, the main surface 5b of the two main surfaces in the thickness direction of the substrate 52 that is not in contact with the fluorescent layer 51 is flush with the inner main surface of the wall portion 31. Alternatively, the substrate 52 may be disposed so as to face the outside of the container 3 and the fluorescent layer 51 may be disposed so as to face the inside S 1 of the container 3 .

[0029] The cooling device 6 is a device that cools the cooling medium 4 and circulates the cooled cooling medium 4 between the container 3 and the cooling device 6. The cooling device 6 has an outlet 6a and an inlet 6b. The outlet 6a is a part that sends out the cooling medium 4 cooled inside the cooling device 6 to the outside (container 3) of the cooling device 6. The outlet 6a is connected to the second end 7b of the first circulation flow path 7. That is, the outlet 6a is connected to the inlet 34 of the container 3 via the first circulation flow path 7. The inlet 6b is a part where the cooling medium 4 that flows out from the outlet hole 35 of the container 3 flows into the cooling device 6. The inlet 6b is connected to the second end 8b of the second circulation flow path 8. That is, the inlet 6b is connected to the outlet hole 35 of the container 3 via the second circulation flow path 8.

[0030] The cooling device 6 cools the cooling medium 4 that has flowed into the inlet 6b, and causes the cooled cooling medium 4 to flow out of the cooling device 6 from the outlet 6a. As a result, the cooling medium 4 cooled by the cooling device 6 flows from the outlet 6a of the cooling device 6 through the first circulation flow path 7 into the interior S1 of the container 3 to cool the fluorescent member 5. Then, the cooling medium 4 that has cooled the fluorescent member 5 returns to the cooling device 6 from the outlet hole 35 of the container 3 through the second circulation flow path 8, and is cooled again. In this way, the cooling device 6 cools the cooling medium 4, and causes the cooled cooling medium 4 to circulate between the cooling device 6 and the container 3.

[0031] (3) Details of the container structure As shown in FIG. 1, the wall portion 31 is, for example, in the shape of a rectangular parallelepiped box, and has at least a first wall portion 311, a second wall portion 312, a third wall portion 313, and a fourth wall portion 314 when viewed in a plan view from a certain direction.

[0032] The first wall portion 311, the second wall portion 312, the third wall portion 313, and the fourth wall portion 314 are connected in an annular (or cylindrical) shape so as to surround the interior S1 of the container 3. More specifically, the first wall portion 311 and the second wall portion 312 are arranged to face each other via the interior S1. The third wall portion 313 and the fourth wall portion 314 are arranged to face each other via the interior S1. One end of both ends of the first wall portion 311 is connected to one end of both ends of the third wall portion 313. The other end of both ends of the first wall portion 311 is connected to one end of both ends of the fourth wall portion 314. One end of both ends of the second wall portion 312 is connected to the other end of both ends of the third wall portion 313. The other end of both ends of the second wall portion 312 is connected to the other end of both ends of the fourth wall portion 314.

[0033] The first wall 311 is provided with an exit portion 33 (i.e., fluorescent member 5). The second wall 312 is provided with an entrance portion 32. The third wall 313 is provided with an inlet hole 34. The fourth wall 314 is provided with an outlet hole 35. The interior S1 of the container 3 includes a flow path R1 that connects the inlet hole 34 and the outlet hole 35, and faces (i.e., contacts) each of the entrance portion 32 and the exit portion 33.

[0034] The flow path R1 is a flow path that passes the cooling medium 4 that has flowed into the inlet hole 34 of the container 3 along the surface (the inner main surface 5b) of the fluorescent member 5, and sends it to the outlet hole 35 of the container 3. The flow path R1 has a first section flow path R11 and two second section flow paths R12. The first section flow path R11 is a section flow path that contacts the fluorescent member 5. The two second section flow paths R12 are section flow paths that are connected to both ends of the first section flow path R11 and do not contact the fluorescent member 5. Of the two second section flow paths R12, one second section flow path R12 is connected to the inlet hole 34 of the container 3. Of the two second section flow paths R12, the other second section flow path R12 is connected to the outlet hole 35 of the container 3.

[0035] As described above, the emission section 33 also serves as the fluorescent member 5. The emission section 33 is formed, for example, in a flat plate shape. The outer main surface of the emission section 33 (i.e., the outer main surface 5a of the fluorescent member 5) is flush with the outer main surface 311a of the first wall section 311. The inner main surface of the emission section 33 (i.e., the inner main surface 5b of the fluorescent member 5) is flush with the inner main surface 311b of the first wall section 311.

[0036] The incident portion 32 has a first major surface 321 and a second major surface 322 .

[0037] The second main surface 322 is a main surface that faces (i.e., is in contact with) the outside of the container 3, and is, for example, a flat surface. The second main surface 322 is flush with the outer main surface 312b of the second wall portion 312.

[0038] The first main surface 321 is a main surface facing (i.e. in contact with) the inside S1 (i.e., flow path R1) of the container 3. The first main surface 321 is a convex surface that protrudes, for example, in a trapezoidal shape from the inner main surface 312a of the second wall portion 312 toward the inside S1 side of the container 3. The first main surface 321 has a first surface portion 321a and two second surfaces 321b. The first surface portion 321a is a surface portion that contacts the first section flow path R11. The first surface portion 321a is a surface portion that corresponds to the upper base of the trapezoid, and is, for example, a plane parallel to the second main surface 322. The two second surfaces 321b are connected to both ends of the first surface portion 321a and are surfaces that contact the second section flow path R12. The two second surface portions 321b extend outward in the opposing direction and toward the second wall portion 312 in the opposing direction of the first wall portion 311 and the second wall portion 312. The two second surface portions 321b are surfaces facing the oblique sides on both sides of the trapezoid, and are, for example, flat surfaces inclined with respect to the first surface portion 321a. The above-mentioned first section flow path R11 contacts the first surface portion 321a. One of the two second section flow paths R12 contacts one of the two second surface portions 321b, and the other second section flow path R12 contacts the other second surface portion 321b.

[0039] The first surface portion 321a is disposed closer to the first wall portion 311 (i.e., closer to the emission portion 33) than the second surface portion 321b. As a result, the cross-sectional area S11 of the first section flow path R11 is smaller than the cross-sectional area S12 of the second section flow path R12. The cross-sectional area S11 of the first section flow path R11 is the cross-sectional area of ​​a cross section perpendicular to the direction P1 in which the cooling medium 4 flows in the first section flow path R11. The cross-sectional area S12 of the second section flow path R12 is the cross-sectional area of ​​a cross section perpendicular to the direction P1 in which the cooling medium 4 flows in the second section flow path R12.

[0040] In this way, since the cross-sectional area S11 of the first section flow path R11 is smaller than the cross-sectional area S12 of the second section flow path R12, the flow rate of the cooling medium 4 flowing through the first section flow path R11 in contact with the fluorescent member 5 is faster than the flow rate of the cooling medium 4 flowing through the second section flow path R12 not in contact with the fluorescent member 5. This improves the cooling performance of the cooling medium 4 for cooling the fluorescent member 5.

[0041] (4) Operation explanation The operation of the light emitting device 1 will now be described with reference to FIG.

[0042] The excitation light C1 emitted from the light source unit 2 crosses the inside S1 (flow path R1) of the container from the entrance unit 32 of the container 3, enters the exit unit 33 (i.e., the fluorescent member 5), and is converted into fluorescence C2 by the fluorescent layer 51 of the fluorescent member 5. The converted fluorescence C2 passes through the fluorescent member 5 and is emitted from the fluorescent member 5 (i.e., the exit unit 33) to the outside of the container 3. Since the fluorescent member 5 also serves as the exit unit 33, when the fluorescence C2 converted by the fluorescent member 5 is emitted to the outside of the container 3, the fluorescence C2 is emitted to the outside of the container 3 without passing through the cooling medium 4 in the container 3. For this reason, the decrease in the light extraction efficiency of the fluorescence C2 from the fluorescent member 5 due to the cooling medium 4 can be reduced. As a result, the light extraction efficiency of extracting the fluorescence C2 from the excitation light C1 emitted from the light source unit 2 can be improved. In this manner, the fluorescence C2 is emitted from the light-emitting device 1.

[0043] Furthermore, the fluorescent member 5 generates heat when converting the excitation light C1 into the fluorescent light C2. The generated heat is dissipated from the fluorescent member 5 to the cooling medium 4 in the container 3. As a result, the fluorescent member 5 is cooled by the cooling medium 4. This cooling can improve the light conversion efficiency in the fluorescent member 5.

[0044] More specifically, in the fluorescent member 5, heat is generated in the fluorescent layer 51. The generated heat is quickly transferred from the fluorescent layer 51 to the substrate 52 of the fluorescent member 5, and then dissipated from the substrate 52 to the cooling medium 4. Due to the presence of the substrate 52, the heat generated in the fluorescent layer 51 is quickly transferred to the substrate 52, so that the heat generated in the fluorescent layer 51 can be quickly removed from the fluorescent layer 51. This can reduce the temperature rise in the fluorescent layer 51, and further improve the light conversion efficiency in the fluorescent layer 51.

[0045] Furthermore, the cooling medium 4 in the interior S1 of the container 3 is cooled by the cooling device 6 and circulated between the cooling device 6. As a result, fresh cooling medium 4 always flows in the interior S1 (flow path R1) of the container 3, and the fluorescent member 5 is effectively cooled by the cooling medium 4. The fluorescent member 5 also serves as the emission section 33, and is not disposed in the interior S1 of the container 3. This makes it possible to reduce disturbance of the flow of the cooling medium 4 in the container 3 by the fluorescent member 5. Therefore, the cooling medium 4 can be made to flow smoothly in the flow path R1 of the container 3, and as a result, the cooling effect of the fluorescent member 5 by the cooling medium 4 can be improved.

[0046] Furthermore, in the flow paths R1 in the container 3, the cross-sectional area S11 of the first section flow path R11 that contacts the fluorescent member 5 is smaller than the cross-sectional area S12 of the second section flow path R12 that does not contact the fluorescent member 5. Therefore, the flow rate of the cooling medium 4 flowing through the first section flow path R11 is faster than the flow rate of the cooling medium 4 flowing through the second section flow path R12. This allows the heat generated in the fluorescent member 5 to be quickly dissipated to the cooling medium 4 flowing through the first section flow path R11. As a result, the cooling effect of the cooling medium 4 on the fluorescent member 5 can be further improved.

[0047] (5) Effects The light-emitting device 1 according to the first embodiment includes a light source unit 2, a fluorescent member 5, a cooling medium 4, a container 3, and a cooling device 6. The light source unit 2 emits excitation light C1. The fluorescent member 5 converts the excitation light C1 from the light source unit 2 into fluorescence C2 and emits the converted fluorescence C2. The cooling medium 4 cools the fluorescent member 5. The container 3 accommodates the cooling medium 4 in its interior S1. The cooling device 6 circulates the cooling medium 4 between the container 3 and the cooling medium 4. The container 3 includes a wall portion 31, an entrance portion 32, and an exit portion 33. The wall portion 31 separates the interior S1 of the container 3 from the outside. The entrance portion 32 is provided on the wall portion 31 and causes the excitation light C1 from the light source unit 2 to enter the interior S1 of the container 3. The exit portion 33 is provided on the wall portion 31 and causes the fluorescence C2 from the fluorescent member 5 to exit the container 3. The fluorescent member 5 also serves as the emission section 33 .

[0048] According to this configuration, since the fluorescent member 5 also serves as the emission section 33, when the fluorescent light C2 is emitted from the fluorescent member 5 to the outside of the container 3, the fluorescent light C2 does not pass through the cooling medium 4 in the container 3. This makes it possible to reduce a decrease in the light extraction efficiency of the fluorescent light C2 from the fluorescent member 5 caused by the cooling medium 4. As a result, it is possible to improve the light extraction efficiency of extracting the fluorescent light C2 from the excitation light C1 emitted from the light source section 2.

[0049] Furthermore, the fluorescent member 5 is provided on the wall 31 of the container 3 by also serving as the emission section 33. This reduces the interference of the fluorescent member 5 with the flow of the cooling medium 4 inside the container 3. As a result, the cooling performance of the cooling medium 4 for the fluorescent member 5 can be improved.

[0050] Moreover, in the light-emitting device 1 according to the first embodiment, the fluorescent member 5 is a transmissive fluorescent member. With this configuration, when the fluorescent member 5 is a transmissive fluorescent member, it is possible to improve the light extraction efficiency of the fluorescence C2 from the fluorescent member 5. As a result, it is possible to improve the light extraction efficiency of extracting the fluorescence C2 from the excitation light C1 emitted from the light source unit 2.

[0051] In the light-emitting device 1 according to the first embodiment, the interior S1 of the container 3 includes a flow path R1 through which the cooling medium 4 flows. The flow path R1 has a first section flow path R11 and a second section flow path R12. The first section flow path R11 contacts the fluorescent member 5. The second section flow path R12 is connected to both ends of the first section flow path R11 and does not contact the fluorescent member 5. The cross-sectional area S11 of the first section flow path R11 is smaller than the cross-sectional area S12 of the second section flow path R12. According to this configuration, the flow rate of the cooling medium 4 flowing through the first section flow path R11 can be made faster than the flow rate of the cooling medium 4 flowing through the second section flow path R12. This can improve the cooling performance of cooling the fluorescent member 5 by the cooling medium 4.

[0052] In the light-emitting device 1 according to the first embodiment, the wall 31 of the container 3 has a first wall 311 and a second wall 312 that face each other with the flow path R1 in between. The incident part 32 is provided on the second wall 312. The emission part 33 is provided on the first wall 311. The incident part 32 has a first surface 321a and a second surface 321b. The first surface 321a contacts the first section flow path R11. The second surface 321b is connected to both ends of the first surface 321a and contacts the second section flow path R12. The first surface 321a is disposed closer to the first wall 311 than the second surface 321b, and the cross-sectional area S11 of the first section flow path R11 is smaller than the cross-sectional area S12 of the second section flow path R12. According to this configuration, by utilizing the shapes of the first surface portion 321a and the second surface portion 321b of the entrance portion 32, the cross-sectional area S11 of the first section flow path R11 can be made smaller than the cross-sectional area S12 of the second section flow path R12.

[0053] In the light-emitting device 1 according to the first embodiment, the fluorescent member 5 also serves as the emission section 33. With this configuration, the incidence section 32 does not have the shape-related condition (the condition that the first surface 321a is disposed closer to the first wall section 311 than the second surface 321b) as the incidence section 32 does.

[0054] Moreover, in the light-emitting device 1 according to the first embodiment, the fluorescent member 5 has a substrate 52 and a fluorescent layer 51. The substrate 52 is transparent. The fluorescent layer 51 is provided on the substrate 52. With this configuration, heat generated in the fluorescent layer 51 can be quickly transferred to the substrate 52. This allows the heat to be quickly removed from the fluorescent layer 51. As a result, the temperature rise in the fluorescent layer 51 can be reduced, and the efficiency of light conversion from the excitation light C1 to the fluorescent light C2 in the fluorescent member 5 can be further improved.

[0055] (6) Variations The first embodiment is merely one of various embodiments of the present disclosure. Various modifications of the first embodiment are possible depending on the design and the like, as long as the object of the present disclosure can be achieved. Modifications of the first embodiment are listed below. The modifications described below can be applied in appropriate combination.

[0056] (6-1) Variation 1 2, the light emitting device 1 according to the first modification is configured similarly to the light emitting device 1 according to the first embodiment, except that the lens 23 of the light source unit 2 is omitted, and instead of the lens 23, the entrance unit 32 has a light collecting function for collecting the excitation light C1 from the light source unit 2. The first modification will be described in detail below. In the following description, the configurations different from the first embodiment will be mainly described, and the same configurations as the first embodiment will be denoted by the same reference numerals as the first embodiment, and the description thereof may be omitted.

[0057] The light source section 2 of the first modification is configured similarly to the light source section 2 of the first embodiment, except that the lens 23 is omitted.

[0058] The incident section 32A of the first modification has the same configuration as the incident section 32 of the first embodiment, except that it has a light collecting function of collecting the excitation light C1 from the light source section 2 onto the fluorescent member 5.

[0059] The incident portion 32A has an incident portion main body 320 and two reflecting members 20.

[0060] The incident portion main body 320 is formed in the same manner as the incident portion 32 of the first embodiment. That is, the incident portion main body 320 has a first main surface 321 and a second main surface 322, and the first main surface 321 has a first surface portion 321a and a second surface portion 321b. The first main surface 321, the second main surface 322, the first surface portion 321a, and the second surface portion 321b of the incident portion main body 320 are formed in the same manner as the first main surface 321, the second main surface 322, the first surface portion 321a, and the second surface portion 321b of the incident portion 32 of the first embodiment.

[0061] The two reflecting members 20 are provided on the two second surface portions 321b of the incident portion main body 320. The reflecting members 20 totally reflect the excitation light C1 incident on the second surface portion 321b from the light source unit 2 toward the fluorescent member 5. The reflecting members 20 are, for example, a metal plate or a metal film having a mirror surface.

[0062] In the first modification, the excitation light C1a of the excitation light C1 from the light source unit 2 propagates from the light source unit 2 inside the incident unit 32A and propagates from the first surface 321a of the incident unit 32A toward the fluorescent member 5. Furthermore, the excitation light C1b of the excitation light C1 from the light source unit 2 propagates from the light source unit 2 inside the incident unit 32A and is incident on the second surface 321b of the incident unit 32A, and is totally reflected toward the fluorescent member 5 by the reflecting member 20 provided on the second surface 321b. Then, the totally reflected excitation light C1b passes through the first surface 321a of the incident unit 32A and propagates toward the fluorescent member 5. In this way, the excitation light C1a and C1b from the light source unit 2 are collected by the incident unit 32A and propagate from the first surface 321a of the incident unit 32A toward the fluorescent member 5. Then, the excitation light C1a and C1b incident on the fluorescent member 5 is converted into fluorescent light C2 and emitted to the outside of the container 3, in the same manner as in the first embodiment.

[0063] According to the first modification, the incident section 32A has a focusing function of focusing the excitation light C1 on the fluorescent member 5. With this configuration, the incident section 32A can efficiently focus the excitation light C1 on the fluorescent member 5. This can improve the efficiency of incidence of the excitation light C1 on the fluorescent member 5. In addition, since the incident section 32A also serves as the lens 23 of the light source section 2, it is no longer necessary to secure a space for providing the lens 23 in the light emitting device 1, which can contribute to miniaturization of the light emitting device 1.

[0064] (6-2) Variation 2 In the first modification, the incident portion 32A collects the excitation light C1 from the light source portion 2 by the reflection member 20. In contrast, in the second modification, the incident portion 32A collects the excitation light C1 from the light source portion 2 by total reflection at the second surface portion 321b of the incident portion 32A. More specifically, in the second modification, the reflection member 20 is omitted in the first modification. In the second modification, the excitation light C1 propagated from the light source portion 2 through the inside of the incident portion 32A and incident on the second surface portion 321b of the incident portion 32A is reflected toward the fluorescent member 5 by total reflection at the second surface portion 321b. That is, in the second modification, the inclination of the second surface portion 321b with respect to the first surface portion 321a is set so that the excitation light C1 propagated from the light source portion 2 through the inside of the incident portion 32A and incident on the second surface portion 321b is reflected toward the fluorescent member 5 by total reflection at the second surface portion 321b. The second modification also provides the same effects as the first modification.

[0065] (6-3) Variation 3 3, the light emitting device 1 according to the modification 3 is configured similarly to the light emitting device 1 according to the modification 1, except that the first main surface 321 of the incident portion 32B is a convex curved surface. The modification 3 will be described in detail below. Note that in the following description, the configuration different from the modification 1 will be mainly described, and the same configuration as the modification 1 will be denoted by the same reference numerals as the modification 1, and the description thereof may be omitted.

[0066] In the light source section 2 of the third modification, similarly to the light source section 2 of the first modification, the lens 23 is omitted.

[0067] The incident section 32B of the modified example 3 is a plano-convex lens having a focusing function of focusing the excitation light C1 from the light source section 2 on the fluorescent member 5. More specifically, the first main surface 321 of the incident section 32B is a convex curved surface protruding from the inner main surface 312a of the second wall section 312 into the interior S1 of the container 3. The second main surface 322 of the incident section 32B is a flat surface that is flush with the outer main surface 312b of the second wall section 312, similar to the case of the modified example 1 (i.e., similar to the case of the first embodiment).

[0068] In the third modification, when the excitation light C1 from the light source unit 2 is incident on the second main surface 322 of the incident portion 32B and emitted from the first main surface 321 of the incident portion 32B, it is refracted at the first main surface 321 of the incident portion 32B and is collected and emitted by the fluorescent member 5. Then, the excitation light C1 incident on the fluorescent member 5 is converted into fluorescence C2 by the fluorescent member 5 and emitted to the outside of the container 3, similarly to the first modification.

[0069] According to the third modification, the incident section 32B has a focusing function of focusing the excitation light C1 on the fluorescent member 5. With this configuration, the incident section 32B can efficiently focus the excitation light C1 on the fluorescent member 5. This can improve the efficiency of incidence of the excitation light C1 on the fluorescent member 5. Furthermore, since the incident section 32B also serves as the lens 23 of the light source section 2, it is no longer necessary to secure a space for providing the lens 23 in the light emitting device 1, which can contribute to miniaturization of the light emitting device 1.

[0070] Furthermore, since incident portion 32B is a plano-convex lens in which first main surface 321 is a convex curved surface and second main surface 322 is a flat surface, it can be easily formed using general plano-convex lens techniques.

[0071] (6-4) Variation 4 In the first embodiment, the fluorescent member 5 may also serve as the incident portion 32, instead of serving as the exit portion 33. In this case as well, the same effects as those of the first embodiment can be achieved.

[0072] (Embodiment 2) A light emitting device 1 according to a second embodiment will be described with reference to the drawings.

[0073] (1) Composition 4, the light emitting device 1 according to the second embodiment is configured similarly to the light emitting device 1 according to the first embodiment, except that the fluorescent member 5 also serves as the incident portion 32, and the second main surface 332 of the exit portion 33 is a convex surface protruding into the interior S1 of the container 3. Hereinafter, the second embodiment will be described in detail. In the following description, the configurations different from the first embodiment will be mainly described, and the same configurations as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and the description thereof may be omitted.

[0074] In the second embodiment, the fluorescent member 5 is formed, for example, in a flat plate shape, and is provided on the wall portion 31 of the container 3 as the incident portion 32. That is, the fluorescent member 5 also serves as the incident portion 32.

[0075] The fluorescent member 5 has a fluorescent layer 51 and a substrate 52, similar to the fluorescent member 5 of the first embodiment. In the example of FIG. 4, the fluorescent member 5 is arranged so that the fluorescent layer 51 faces the interior S1 of the container 3, and the substrate 52 faces the exterior of the container 3. The inner main surface 5a of the fluorescent member 5 (the inner main surface of the fluorescent layer 51) is flush with the inner main surface of the wall portion 31 (the inner main surface 312a of the second wall portion 312). The outer main surface 5b of the fluorescent member 5 (the outer main surface of the substrate 52) is flush with the outer main surface of the wall portion 31 (the outer main surface 312b of the second wall portion 312). Note that the fluorescent layer 51 may be arranged to face the exterior of the container 3, and the substrate 52 may be arranged to face the interior S1 of the container 3.

[0076] The wall 31 of the container 3, like the wall 31 of embodiment 1, is, for example, a rectangular box-shaped, and when viewed in a plan view from a certain direction, has at least a first wall 311, a second wall 312, a third wall 313, and a fourth wall 314.

[0077] The first wall 311 is provided with an exit portion 33. The second wall 312 is provided with an entrance portion 32 (i.e., fluorescent member 5). The third wall 313 is provided with an inlet hole 34. The fourth wall 314 is provided with an outlet hole 35. The interior S1 of the container 3 includes a flow path R1 that connects the inlet hole 34 and the outlet hole 35, and faces (i.e., contacts) each of the entrance portion 32 and the exit portion 33.

[0078] The flow path R1 has a first section flow path R11 and two second section flow paths R12. The first section flow path R11 is a section flow path that contacts the fluorescent member 5. The two second section flow paths R12 are section flow paths that are connected to both ends of the first section flow path R11 and do not contact the fluorescent member 5.

[0079] In the second embodiment, as described above, the incident portion 32 also serves as the fluorescent member 5. The incident portion 32 is formed, for example, in a flat plate shape. The outer main surface of the incident portion 32 (i.e., the outer main surface 5a of the fluorescent member 5) is flush with the outer main surface 312b of the second wall portion 312. The inner main surface of the incident portion 32 (i.e., the inner main surface 5a of the fluorescent member 5) is flush with the inner main surface 312a of the second wall portion 312.

[0080] The emission section 33 has a first main surface 331 and a second main surface 332 .

[0081] The first main surface 331 is a main surface that faces the outside of the container 3, and is, for example, a flat surface. The first main surface 331 is flush with the outer main surface 311a of the first wall portion 311.

[0082] The second main surface 332 is a main surface facing the inside S1 of the container 3 (i.e., the flow path R1). The second main surface 332 is a convex surface that protrudes, for example, in a trapezoidal shape from the inner main surface 311b of the first wall portion 311 toward the inside S1 side of the container 3. The second main surface 332 has a first surface portion 332a and two second surfaces portion 332b. The first surface portion 332a is a surface portion that contacts the first section flow path R11. The first surface portion 332a is a surface portion that corresponds to the upper base of the trapezoid, and is, for example, a plane parallel to the first main surface 331. The two second surfaces portion 332b are connected to both ends of the first surface portion 332a and are surfaces that contact the second section flow path R12. The two second surfaces 332b extend outward in the opposing direction and toward the first wall 311 in the opposing direction between the first wall 311 and the second wall 312. The two second surfaces 332b are surfaces facing the oblique sides on both sides of the trapezoid, and are, for example, flat surfaces inclined with respect to the first surface 332a.

[0083] The first surface portion 332a is disposed closer to the second wall portion 312 (i.e., closer to the incident portion 32) than the second surface portion 332b. As a result, the cross-sectional area S11 of the first section flow path R11 is smaller than the cross-sectional area S12 of the second section flow path R12. The cross-sectional area S11 of the first section flow path R11 is the cross-sectional area of ​​a cross section perpendicular to the direction P1 in which the cooling medium 4 flows in the first section flow path R11. The cross-sectional area S12 of the second section flow path R12 is the cross-sectional area of ​​a cross section perpendicular to the direction P1 in which the cooling medium 4 flows in the second section flow path R12.

[0084] In this way, since the cross-sectional area S11 of the first section flow path R11 is smaller than the cross-sectional area S12 of the second section flow path R12, the flow rate of the cooling medium 4 flowing through the first section flow path R11 in contact with the fluorescent member 5 is faster than the flow rate of the cooling medium 4 flowing through the second section flow path R12 not in contact with the fluorescent member 5. This improves the cooling performance of the cooling medium 4 for cooling the fluorescent member 5.

[0085] (2) Operation Description The operation of the light emitting device 1 according to the second embodiment will be described with reference to FIG.

[0086] The excitation light C1 emitted from the light source unit 2 enters the fluorescent member 5 (incident section 32) and is converted into fluorescence C2 by the fluorescent layer 51 of the fluorescent member 5. The converted fluorescence C2 then traverses the inside S1 (flow path R1) of the container from the fluorescent member 5, passes through the exit section 33, and is emitted to the outside of the container 3. Since the fluorescent member 5 also serves as the incident section 32, the excitation light C1 incident on the fluorescent member 5 from the light source unit 2 enters the fluorescent member 5 without passing through the cooling medium 4 in the container 3. For this reason, the decrease in the efficiency of incidence of the excitation light C1 on the fluorescent member 5 caused by the cooling medium 4 can be reduced. In this manner, the fluorescence C2 is emitted from the light-emitting device 1.

[0087] Furthermore, in the fluorescent member 5, heat is generated when the excitation light C1 is converted into the fluorescent light C2. The generated heat is dissipated from the fluorescent member 5 to the cooling medium 4 in the container 3. As a result, the fluorescent member 5 is cooled by the cooling medium 4. In this manner, the fluorescent member 5 is cooled by the cooling medium 4, and thus the light conversion efficiency in the fluorescent member 5 can be improved.

[0088] Furthermore, the cooling medium 4 in the container 3 is cooled by the cooling device 6 and circulated between the container 3 and the cooling device 6. As a result, fresh cooling medium 4 always flows in the interior S1 (flow path R1) of the container 3, and the fluorescent member 5 is effectively cooled by the cooling medium 4. The fluorescent member 5 also serves as the entrance portion 32, and is not disposed in the interior S1 of the container 3. This makes it possible to reduce disturbance of the flow of the cooling medium 4 in the container 3 by the fluorescent member 5. Therefore, the cooling medium 4 can be made to flow smoothly in the flow path R1 of the container 3, and as a result, the cooling effect of the fluorescent member 5 by the cooling medium 4 can be improved.

[0089] Furthermore, in the flow passage R1 of the container 3, the cross-sectional area S11 of the first section flow passage R11 that contacts the fluorescent member 5 is smaller than the cross-sectional area S12 of the second section flow passage R12 that does not contact the fluorescent member 5. Therefore, the flow rate of the cooling medium 4 flowing through the first section flow passage R11 is faster than the flow rate of the cooling medium 4 flowing through the second section flow passage R12. This allows the heat generated in the fluorescent member 5 to be quickly dissipated to the cooling medium 4 flowing through the first section flow passage R11. As a result, the cooling effect of the cooling medium 4 on the fluorescent member 5 can be further improved.

[0090] (3) Effects In the light emitting device 1 according to the second embodiment, the same components as those of the light emitting device 1 according to the first embodiment provide the same effects as those of the first embodiment.

[0091] The light-emitting device 1 according to the second embodiment includes a light source unit 2, a fluorescent member 5, a cooling medium 4, a container 3, and a cooling device 6. The light source unit 2 emits excitation light C1. The fluorescent member 5 converts the excitation light C1 from the light source unit 2 into fluorescence C2 and emits the converted fluorescence C2. The cooling medium 4 cools the fluorescent member 5. The container 3 accommodates the cooling medium 4 in its interior S1. The cooling device 6 circulates the cooling medium 4 between the container 3 and the cooling medium 4. The container 3 includes a wall portion 31, an entrance portion 32, and an exit portion 33. The wall portion 31 separates the interior S1 of the container 3 from the outside. The entrance portion 32 is provided on the wall portion 31 and causes the excitation light C1 from the light source unit 2 to enter the interior S1 of the container 3. The exit portion 33 is provided on the wall portion 31 and causes the fluorescence C2 from the fluorescent member 5 to exit the container 3. The fluorescent member 5 also serves as the incident portion 32 .

[0092] According to this configuration, the fluorescent member 5 also serves as the incident portion 32, so when the excitation light C1 from the light source unit 2 is incident on the fluorescent member 5, the excitation light C1 does not pass through the cooling medium 4 in the container 3. This makes it possible to reduce a decrease in the incidence efficiency of the excitation light C1 on the fluorescent member 5 caused by the cooling medium 4. As a result, it is possible to improve the light extraction efficiency for extracting the fluorescence C2 from the excitation light C1 emitted from the light source unit 2.

[0093] In the light-emitting device 1 according to the second embodiment, the wall 31 of the container 3 has a first wall 311 and a second wall 312. The first wall 311 and the second wall 312 face each other across the flow path R1. The incident part 32 is provided on the second wall 312. The emission part 33 is provided on the first wall 311. The emission part 33 has a first surface 332a and a second surface 332b. The first surface 332a contacts the first section flow path R11. The second surface 332b is connected to an end of the first surface 332a and contacts the second section flow path R12. The first surface 332a is disposed closer to the second wall 312 than the second surface 332b, and the cross-sectional area S11 of the first section flow path R11 is smaller than the cross-sectional area S12 of the second section flow path R12.

[0094] According to this configuration, by utilizing the shapes of the first surface portion 332a and the second surface portion 332b of the emission portion 33, the cross-sectional area S11 of the first section flow path R11 can be made smaller than the cross-sectional area S12 of the second section flow path R12.

[0095] In the light-emitting device 1 according to the second embodiment, the fluorescent member 5 also serves as the incident portion 32. With this configuration, the incident portion 32 does not have the shape-related condition (the condition that the first surface portion 332a is disposed closer to the second wall portion 312 than the second surface portion 332b) as the incident portion 32 does.

[0096] In the light-emitting device 1 according to the second embodiment, the fluorescent member 5 also serves as the incident portion 32. With this configuration, the incident portion 32 does not have the shape-related condition (the condition that the first surface portion 332a is disposed closer to the second wall portion 312 than the second surface portion 332b) as the incident portion 32 does.

[0097] (4) Variations The second embodiment is merely one of various embodiments of the present disclosure. Various modifications of the second embodiment are possible depending on the design and the like, as long as the object of the present disclosure can be achieved. Modifications of the second embodiment are listed below. The modifications described below can be applied in appropriate combination.

[0098] (4-1) Variation 1 5, the light emitting device 1 according to the first modification has a similar configuration to the light emitting device 1 according to the second embodiment, except that the emission section 33A has a light collecting function for collecting the fluorescence C2 emitted from the fluorescent member 5. The first modification will be described in detail below. In the following description, the configuration different from the second embodiment will be mainly described, and the same configuration as the second embodiment will be denoted by the same reference numerals as the second embodiment, and the description thereof may be omitted.

[0099] The emission section 33A of the first modification is configured similarly to the emission section 33 of the second embodiment, except that the emission section 33A has a light collecting function for collecting the fluorescence C2 emitted from the fluorescent member 5.

[0100] The emission section 33A has an emission section main body 330 and two reflecting members 30.

[0101] The emission section main body 330 is formed in the same manner as the emission section 33 of the second embodiment. That is, the emission section main body 330 has a first main surface 331 and a second main surface 332, and the second main surface 332 has a first surface portion 332a and a second surface portion 332b. The first main surface 331, the second main surface 332, the first surface portion 332a, and the second surface portion 332b of the emission section main body 330 are formed in the same manner as the first main surface 331, the second main surface 332, the first surface portion 332a, and the second surface portion 332b of the emission section 33 of the second embodiment.

[0102] The two reflecting members 30 are provided on the two second surface portions 332b of the emitter main body 330. The reflecting members 30 totally reflect the fluorescence C2 that has propagated from the fluorescent member 5 through the inside of the emitter main body 330 and is incident on the second surface portions 332b, in a direction perpendicular to the first main surface 331 of the emitter 33. The reflecting members 30 are, for example, a metal plate or metal film having a mirror surface.

[0103] In the first modification, the excitation light C1 from the light source unit 2 is incident on the fluorescent member 5 (incident unit 32) and converted into fluorescence C2 by the fluorescent member 5. Then, the fluorescence C2a of the converted fluorescence C2 is incident on the first surface 332a of the emission unit 33A from the fluorescent member 5, propagates inside the emission unit 33A toward the first main surface 331 of the emission unit 33A, and is emitted from the first main surface 331 to the outside of the container 3. Meanwhile, the fluorescence C2b of the converted fluorescence C2 is propagated from the fluorescent member 5 inside the emission unit 33A, incident on the second surface 332b of the emission unit 33A, and is totally reflected by the reflecting member 30 provided on the second surface 332b toward the first main surface 331 of the emission unit 33A. Then, the totally reflected fluorescence C2 is emitted from the first main surface 331 of the emission unit 33A to the outside of the container 3. In this manner, the fluorescence C2a and C2b from the fluorescent member 5 are collected by the emission section 33A and emitted to the outside of the container 3 from the first main surface 331 of the emission section 33. For example, the fluorescence C2a and C2b from the fluorescent member 5 are converged in a direction perpendicular to the first main surface 331 of the emission section 33 and emitted to the outside of the container 3.

[0104] According to the first modification, the emission section 33A has a light collecting function for collecting the fluorescence C2 from the fluorescent member 5. According to this configuration, the emission section 33A can collect the fluorescence C2 and emit it to the outside of the container 3.

[0105] (4-2) Variation 2 In the first modification, the emission section 33A collects the fluorescence C2 from the fluorescent member 5 by the reflection member 30. In contrast to this, in the second modification, the emission section 33A collects the fluorescence C2 from the fluorescent member 5 by total reflection at the second surface 332b of the emission section 33A. More specifically, in the second modification, the reflection member 30 is omitted from the first modification. In the second modification, the fluorescence C2 propagated from the fluorescent member 5 inside the emission section 33A and incident on the second surface 332b of the emission section 33A is reflected toward the first main surface 331 of the emission section 33A by total reflection at the second surface 332b. That is, in Modification 2, the inclination of second surface 332b with respect to first surface 332a in emission section 33A is set so that fluorescence C2 which propagates from the fluorescent member 5 inside emission section 33A and enters second surface 332b is reflected by total reflection at second surface 332b toward first main surface 331 of emission section 33A. Modification 2 also provides the same effects as Modification 1.

[0106] (4-3) Variation 3 6, the light emitting device 1 according to the third modification is configured similarly to the light emitting device 1 according to the second embodiment, except that the first main surface 331 of the emission portion 33B is a convex curved surface. The second modification will be described in detail below. Note that in the following description, the configurations different from the second embodiment will be mainly described, and the same configurations as the second embodiment will be denoted by the same reference numerals as the second embodiment, and the description thereof may be omitted.

[0107] The emission section 33B of the third modification is a lens having a light collecting function for collecting fluorescence C2 from the fluorescent member 5 and emitting the light to the outside of the container 3. More specifically, the first main surface 331 of the emission section 33B is a convex curved surface protruding from the outer main surface 311a of the first wall section 311 to the outside of the container 3. The second main surface 332 of the emission section 33B is a convex surface protruding in a trapezoidal shape from the inner main surface 311b of the first wall section 311 to the inside S1 of the container 3, similar to the second main surface 322 of the emission section 33 of the second embodiment.

[0108] In the third modification, the excitation light C1 from the light source unit 2 is incident on the fluorescent member 5 (i.e., the incident portion 32) and converted into fluorescence C2 by the fluorescent member 5. The converted fluorescence C2 is emitted from the fluorescent member 5 and incident on the second main surface 332 of the emission portion 33. Then, when the fluorescence C2 from the fluorescent member 5 is incident on the second main surface 332 of the emission portion 33B and emitted from the first main surface 331 of the emission portion 33B, it is refracted by the first main surface 331 (convex curved surface) of the emission portion 33B and is converged and emitted to the outside of the container 3. For example, the fluorescence C2 is converged in a direction perpendicular to the outer main surface 311a of the first wall portion 311 and emitted to the outside of the container 3.

[0109] According to the third modification, the emission section 33B has a light collecting function for collecting the fluorescence C2 from the fluorescent member 5. According to this configuration, the fluorescence C2 emitted from the emission section 33B can be converged.

[0110] (4-4) Variation 4 The light-emitting device 1 of variant example 4 is configured in the same manner as the light-emitting device 1 of embodiment 2, except that the cooling medium 4 has the property of absorbing light in a specific wavelength range contained in the excitation light C1 emitted from the light source unit 2 (light absorption property).

[0111] The light source unit 2 of the fourth modification emits excitation light C1 including light in a specific wavelength region, similar to the light source unit 2 of the second embodiment. The specific wavelength region is, for example, a blue wavelength region (a wavelength region of 435 nm or more and 480 nm or less) or a violet wavelength region (a wavelength region of 380 nm or more and 435 nm or less).

[0112] The cooling medium 4 of the fourth modification has a property of absorbing light in the specific wavelength region (light absorption property). More specifically, the cooling medium 4 of the fourth modification contains a dye that absorbs light in the specific wavelength region. The cooling medium 4 of the fourth modification is required to have light absorbance, light resistance, and heat resistance as properties.

[0113] The dye contained in the cooling medium 4 is, for example, a phthalocyanine dye, a porphyrin dye, a coumarin dye, a rhodamine dye, or a cyanine dye. These dyes can absorb light in the blue wavelength region (wavelength region of 435 nm or more and 480 nm or less) and the violet wavelength region (wavelength region of 380 nm or more and 435 nm or less). In other words, by containing the above dye, the cooling medium 4 can absorb light in the above specific wavelength region emitted from the light source unit 2.

[0114] Consider a case where a crack occurs in the fluorescent member 5 in FIG. 4. In this case, most of the excitation light C1 from the light source unit 2 (i.e., excitation light including light in a specific wavelength region) is converted to fluorescence C2 by the fluorescent member 5 and emitted from the fluorescent member 5. However, the remaining part of the excitation light C1 from the light source unit 2 passes through the crack in the fluorescent member 5, and is emitted from the fluorescent member 5 as excitation light C1 without being converted to fluorescence C2. In this way, the light in the specific wavelength region contained in the excitation light C1 that has passed through the crack in the fluorescent member 5 without being converted to fluorescence C2 is absorbed by the light absorption characteristics of the cooling medium 4 when passing through the cooling medium 4 in the inside S1 of the container 3. For this reason, the light in the specific wavelength region that is a part of the excitation light C1 that has passed through the crack in the fluorescent member 5 without being converted to fluorescence C2 is not emitted to the outside of the container 3. Therefore, only the fluorescence C2 converted by the fluorescent member 5 is emitted to the outside of the container 3 through the emission part. In this way, since the cooling medium 4 has the light absorption property of absorbing light in a specific wavelength range, even if a crack occurs in the fluorescent component 5, it is possible to reduce the emission of light in the specific wavelength range contained in the excitation light C1 from the light source unit 2 to the outside of the container 3 from the emission unit 33.

[0115] According to the fourth modification, the fluorescent member 5 also serves as the incident section 32. The excitation light C1 emitted from the light source section 2 contains light in a specific wavelength region. The cooling medium 4 has the property of absorbing light in a specific wavelength region. According to this configuration, the light in the specific wavelength region contained in the excitation light C1 emitted from the fluorescent member 5 without being converted to fluorescence C2 in the fluorescent member 5 can be absorbed by the cooling medium 4. This makes it possible to reduce the emission of the light in the specific wavelength region contained in the excitation light C1 to the outside of the container 3.

[0116] (4-5) Variation 5 In the second embodiment, the fluorescent member 5 may also serve as the exit portion 33, instead of the entrance portion 32. In this case as well, the same effects as those of the second embodiment can be achieved.

[0117] (Aspect) As is apparent from the above-described embodiment and modified examples, the present specification discloses the following aspects.

[0118] The light emitting device (1) according to the first aspect includes a light source unit (2), a fluorescent member (5), a cooling medium (4), a container (3), and a cooling device (6). The light source unit (2) emits excitation light (C1). The fluorescent member (5) converts the excitation light (C1) from the light source unit (2) into fluorescent light (C2) and emits the converted fluorescent light (C2). The cooling medium (4) cools the fluorescent member (5). The container (3) accommodates the cooling medium (4) inside (S1). The cooling device (6) circulates the cooling medium (4) between the container (3) and the cooling device (6), and cools the cooling medium (4). The container (3) includes a wall portion (31), an entrance portion (32; 32A; 32B), and an exit portion (33; 33A; 33B). The wall portion (31) separates the inside (S1) and the outside of the container (3). The incident portion (32; 32A; 32B) is provided on the wall portion (31) and allows the excitation light (C1) from the light source portion (2) to enter the inside (S1) of the container (3). The exit portion (33; 33A; 33B) is provided on the wall portion (31) and allows the fluorescence (C2) from the fluorescent member (5) to exit the container (3). The fluorescent member (5) serves as both the incident portion (32) and the exit portion (33).

[0119] According to this configuration, in a configuration in which the fluorescent member (5) also serves as the entrance portion (32), when the excitation light (C1) from the light source portion (2) enters the fluorescent member (5), the excitation light (C1) does not pass through the cooling medium (4) in the container (3). Therefore, it is possible to reduce a decrease in the incidence efficiency of the excitation light (C1) on the fluorescent member (5) caused by the cooling medium (4). As a result, it is possible to improve the light extraction efficiency of extracting the fluorescent light (C2) from the excitation light (C1) emitted from the light source portion (2). Furthermore, in a configuration in which the fluorescent member (5) also serves as the exit portion (33), when the fluorescent light (C2) is emitted from the fluorescent member (5) to the outside of the container (3), the fluorescent light (C2) does not pass through the cooling medium (4) in the container (3). Therefore, it is possible to reduce a decrease in the light extraction efficiency of the fluorescent light (C2) from the fluorescent member (5) caused by the cooling medium (4). As a result, it is possible to improve the light extraction efficiency for extracting the fluorescent light (C2) from the excitation light (C1) emitted from the light source section (2).

[0120] Moreover, the fluorescent member (5) is provided inside the wall portion (31) of the container (3) by also serving as the entrance portion (32) or the exit portion (33). This reduces the fluorescent member (5) from interfering with the flow of the cooling medium (4) inside (S1) of the container (3). As a result, the cooling performance of the cooling medium (4) for the fluorescent member (5) can be improved.

[0121] In the light emitting device (1) according to the second aspect, the fluorescent member (5) in the first aspect is a transmissive fluorescent member.

[0122] According to this configuration, when the fluorescent member (5) is a transmissive fluorescent member, it is possible to improve the light extraction efficiency for extracting the fluorescent light (C2) from the excitation light (C1) emitted from the light source section (2).

[0123] In the light emitting device (1) according to the third aspect, in the first or second aspect, the interior (S1) of the container (3) includes a flow path (R1) through which the cooling medium (4) flows. The flow path (R1) has a first section flow path (R11) and a second section flow path (R12). The first section flow path (R11) contacts the fluorescent member (5). The second section flow path (R12) is connected to both ends of the first section flow path (R11) and does not contact the fluorescent member (5). The cross-sectional area (S11) of the first section flow path (R11) is smaller than the cross-sectional area (S12) of the second section flow path (R12).

[0124] According to this configuration, the flow rate of the cooling medium (4) flowing through the first section flow path (R11) in contact with the fluorescent member (5) can be made faster than the flow rate of the cooling medium (4) flowing through the second section flow path (R12), thereby improving the cooling performance for cooling the fluorescent member (5).

[0125] In the light-emitting device (1) according to the fourth aspect, in the third aspect, the wall (31) of the container (3) has a first wall (311) and a second wall (312) facing each other with a flow path (R1) therebetween. The incident part (32) is provided on the second wall (312). The exit part (33) is provided on the first wall (311). The incident part (32) has a first surface (321a) and a second surface (321b). The first surface (321a) contacts the first section flow path (R11). The second surface (321b) is connected to both ends of the first surface (321a) and contacts the second section flow path (R12). The first surface portion (321a) is disposed closer to the first wall portion (311) than the second surface portion (321b), and the cross-sectional area (S11) of the first section flow path (R11) is smaller than the cross-sectional area (S12) of the second section flow path (R12).

[0126] According to this configuration, by utilizing the shapes of the first surface portion (321a) and the second surface portion (321b) of the incident portion (32), the cross-sectional area (S11) of the first section flow path (R11) can be made smaller than the cross-sectional area (S12) of the second section flow path (R12).

[0127] In the light emitting device (1) according to the fifth aspect, the fluorescent member (5) in the fourth aspect also serves as the emission part (33).

[0128] According to this configuration, the incident portion (32) does not have any shape-related condition like the exit portion (33) (the condition that the first surface portion (321a) is positioned closer to the first wall portion (311) than the second surface portion (321b)), so it is easy to use the fluorescent member (5) as both the incident portion (32).

[0129] In the light-emitting device (1) according to the sixth aspect, in the third aspect, the wall (31) of the container (3) has a first wall (311) and a second wall (312) facing each other with a flow path (R1) therebetween. The incident part (32) is provided on the second wall (312). The exit part (33) is provided on the first wall (311). The exit part (33) has a first surface (332a) and a second surface (332b). The first surface (332a) contacts the first section flow path (R11). The second surface (332b) is connected to both ends of the first surface (332a) and contacts the second section flow path (R12). The first surface portion (332a) is disposed closer to the second wall portion (312) than the second surface portion (332b), and the cross-sectional area (S11) of the first section flow path (R11) is smaller than the cross-sectional area (S12) of the second section flow path (R12).

[0130] According to this configuration, by utilizing the shapes of the first surface portion (332a) and the second surface portion (332b) of the emission portion (33), the cross-sectional area (S11) of the first section flow path (R11) can be made smaller than the cross-sectional area (S12) of the second section flow path (R12).

[0131] In the light emitting device (1) according to the seventh aspect, in the sixth aspect, the fluorescent member (5) also serves as the incident portion (32).

[0132] According to this configuration, the incident portion (32) does not have any shape-related conditions as the exit portion (33) does (the condition that the first surface portion (332a) is positioned closer to the second wall portion (312) than the second surface portion (332b)), so it is easy to use the fluorescent member (5) as both the incident portion (32).

[0133] In the light emitting device (1) according to an eighth aspect, in any one of the first to seventh aspects, the fluorescent member (5) has a substrate (52) and a fluorescent layer (51). The substrate (52) is transparent. The fluorescent layer (51) is provided on the substrate (52).

[0134] According to this configuration, heat generated in the fluorescent layer (51) can be quickly transferred to the substrate (52). This allows the heat to be quickly removed from the fluorescent layer (51). As a result, it is possible to reduce a temperature rise in the fluorescent layer (51) and improve the efficiency of light conversion from the excitation light (C1) to fluorescent light (C2) in the fluorescent layer (51).

[0135] In the light emitting device (1) according to a ninth aspect, in any one of the first to eighth aspects, the entrance portion (32A) has a light collecting function of collecting the excitation light (C1) on the fluorescent member (5).

[0136] According to this configuration, the excitation light (C1) can be efficiently collected on the fluorescent member (5) by the incident portion (32A). This improves the efficiency of incidence of the excitation light (C1) on the fluorescent member (5). In addition, since the incident portion (32) also serves as the light collecting member having the light collecting function, it is not necessary to secure a space for providing the light collecting member in the light-emitting device (1), which contributes to the miniaturization of the light-emitting device (1).

[0137] In the light emitting device (1) according to a tenth aspect, in any one of the first to ninth aspects, the emission part (33A) has a light collecting function for collecting the fluorescence (C2) from the fluorescent member (5).

[0138] According to this configuration, the fluorescent light (C2) emitted from the emission part (33A) can be converged.

[0139] In the light emitting device (1) according to an eleventh aspect, in any one of the first to tenth aspects, the fluorescent member (5) also serves as the incident part (32). The excitation light (C1) emitted from the light source part (2) includes light in a specific wavelength region. The cooling medium (4) has a property of absorbing light in the specific wavelength region.

[0140] According to this configuration, the light in a specific wavelength region contained in the excitation light (C1) emitted from the fluorescent member (5) without being converted to fluorescent light (C2) in the fluorescent member (5) can be absorbed by the cooling medium (4), thereby making it possible to reduce the emission of the light in the specific wavelength region contained in the excitation light (C1) to the outside of the container (3). [Explanation of symbols]

[0141] 1 Light-emitting devices 2 Light source section 3 containers 4 Cooling medium 5 Fluorescent materials 6 Cooling device 31 Wall 32,32A,32B Input part 33,33A,33B Output part 51 Fluorescent Layer 52 Substrate 311 1st wall section 312 2nd wall section 321a, 332a First side 321b,332b 2nd side part C1 Excitation light C2 Fluorescence Inside the S1 vessel R1 flow path R11 1st section flow path R12 2nd section flow path S1 internal S11 Cross-sectional area S12 cross-sectional area

Claims

1. A light source unit that emits excitation light; a fluorescent member that converts the excitation light from the light source unit into fluorescence and emits the converted fluorescence; A cooling medium for cooling the fluorescent member; A container containing the cooling medium therein; a cooling device that circulates the cooling medium between the container and the cooling medium and cools the cooling medium; The container comprises: A wall portion separating the interior and the exterior of the container; an incidence section provided on the wall section and allowing the excitation light from the light source section to be incident on the inside of the container; an emission portion provided on the wall portion to emit the fluorescent light from the fluorescent member to the outside of the container, The fluorescent member is used as either the incident portion or the exit portion. Light emitting device.

2. The fluorescent member is a transmissive fluorescent member.

10. The light emitting device of claim 1.

3. the interior of the container includes a flow path through which the cooling medium flows; The flow path is a first section flow path in contact with the fluorescent member; a second section flow path connected to both ends of the first section flow path and not in contact with the fluorescent member; A cross-sectional area of ​​the first section flow path is smaller than a cross-sectional area of ​​the second section flow path.

3. A light emitting device according to claim 1 or 2.

4. The wall portion of the container includes a first wall portion and a second wall portion opposed to each other across the flow path, the incidence portion is provided on the second wall portion, The emission portion is provided on the first wall portion, The incident portion is a first surface portion in contact with the first section flow path; a second surface portion connected to both ends of the first surface portion and in contact with the second section flow path, the first surface portion is disposed closer to the first wall portion than the second surface portion, and a cross-sectional area of ​​the first section flow path is smaller than a cross-sectional area of ​​the second section flow path; The light emitting device of claim 3.

5. The fluorescent member also serves as the emission portion.

5. The light emitting device of claim 4.

6. The wall portion of the container includes a first wall portion and a second wall portion opposed to each other across the flow path, the incidence portion is provided on the second wall portion, The emission portion is provided on the first wall portion, The emission section is a first surface portion in contact with the first section flow path; a second surface portion connected to an end of the first surface portion and in contact with the second section flow path, the first surface portion is disposed closer to the second wall portion than the second surface portion, and a cross-sectional area of ​​the first section flow path is smaller than a cross-sectional area of ​​the second section flow path; The light emitting device of claim 3.

7. The fluorescent member is also used as the incident portion.

7. The light emitting device of claim 6.

8. The fluorescent member is A transparent substrate; A fluorescent layer provided on the substrate.

3. A light emitting device according to claim 1 or 2.

9. The incident portion has a light collecting function of collecting the excitation light on the fluorescent member.

3. A light emitting device according to claim 1 or 2.

10. The emission section has a light collecting function of collecting the fluorescent light from the fluorescent member.

3. A light emitting device according to claim 1 or 2.

11. The fluorescent member also serves as the incident portion, the excitation light emitted from the light source unit includes light in a specific wavelength range, The cooling medium has a characteristic of absorbing light in the specific wavelength range.

3. A light emitting device according to claim 1 or 2.

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