JP2013089419A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device capable of improving an amount of light of wavelength-converted light of which the wavelength is converted and attaining bright illumination.SOLUTION: In the lighting device 100, a wavelength conversion unit 300 includes a wavelength conversion member 302 for converting excited light into a desired wavelength-converted light, a light transmission section 328 having a function for transmitting the excited light and the wavelength-converted light, and a holding member 304 having a through-hole 320 having a function for internally holding the light transmission section. An excited light emitting end 206 of a light source 200 separated from a light conversion member is arranged in the vicinity of a light-incident section 322 as one end of the through-hole. The light conversion section is separated from the holding member, and a part of the light transmission section is arranged at a gap between the excited-light emitting end and the light conversion member, and at least a part of the light conversion member is continuously formed from the light-incident section to a light-emitting section 324 as the other end of the through-hole of the holding member. Further, the lighting device 100 has a function for thermally connecting the light conversion member and the holding member, and has a heat conductive member 308 having a heat conductivity higher than that of a light transmission member 306 arranged at the light transmission section.

Description

  The present invention relates to a lighting device.

  Currently, fiber light sources combining a small solid light source and an optical fiber have been developed. This fiber light source is used, for example, as an illumination device that emits light from the tip of a thin structure.

  As such an illuminating device, for example, Patent Document 1 proposes a fiber light source device (light emitting device) using a solid light source. 9A and 9B show a conventional illumination device disclosed in Patent Document 1, wherein FIG. 9A is a diagram showing a schematic configuration around a wavelength conversion member, and FIG. 9B is a front view of a spacer used in the illumination device. , (C) is a perspective view of the spacer.

  In the fiber light source device disclosed in Patent Document 1, a fiber (optical fiber) 920 is connected to a small solid light source (not shown), and a wavelength conversion member (phosphor) 940 is installed at the tip of the fiber 920. . The fiber 920 is attached to the holding member 930, and a spacer 950 is installed between the fiber 920 and the wavelength conversion member 940. The spacer 950 has a through hole 950c, and a metal thin film 950a is formed on the surface. In this fiber light source device, the backward emission light emitted from the wavelength conversion member 940 to the fiber 920 side is reflected by the reflecting portion made of the metal thin film 950a provided on the inner surface of the through hole 950c of the spacer 950, thereby returning to the fiber 920 side. Is returned to the wavelength conversion member 940 side to increase the illumination light quantity of the wavelength conversion light.

  Such a fiber light source device disclosed in Patent Document 1 is provided on a light emitting element, a fiber that guides light from the light emitting element, a holding member that is attached to at least an emission side end of the fiber, and an emission side of the fiber, A wavelength conversion member that absorbs at least part of the light from the light emitting element and converts it into light of a different wavelength, and a rear side from the wavelength conversion member between the holding member or the fiber and the wavelength conversion member It has a structure with a spacer that reflects the emitted light, and this structure can reduce the loss of light caused by the light reflected or generated by the wavelength conversion member entering the end face of the holding member, thus improving the light output Can be made. Therefore, the brightness can be improved by providing means for reflecting the backward emission light that has not been used effectively until then in the direction in which the light should be output.

JP 2009-3228 A

  The above-described fiber light source device is configured to cover the entire exit side opening of the spacer 950 with the wavelength conversion member 940. For this reason, the backward emission light reflected by the reflection part which is the inner surface of the through-hole 950c of the spacer 950 passes through the wavelength conversion member 940 and is output to the outside. However, the wavelength conversion member 940 generally has a characteristic of scattering visible light and a characteristic of absorbing wavelength-converted wavelength light generated by itself. In this way, a part of the wavelength-converted light that has been wavelength-converted by itself is absorbed, or light that is originally output effectively is scattered, so that the amount of wavelength-converted light emitted to the outside is reduced. . Therefore, in the configuration of the above-described fiber light source device, there is a problem that the wavelength conversion light from the wavelength conversion member 940 cannot be sufficiently utilized, and the light extraction efficiency is not improved as expected.

  In addition, since the distance between the tip of the fiber (optical fiber) 920 and the wavelength conversion member (phosphor) 940 is close, and there is no material regulation for the wavelength conversion member 940 and its surrounding members, the wavelength conversion member The problem is that the amount of heat generated along with the wavelength conversion by the 940 is concentrated locally around the bottom surface of the wavelength conversion member 940, the wavelength conversion member 940 and its surrounding members are likely to be thermally deteriorated, and the light quantity of the light emitting element cannot be increased so much. There is.

  This invention is made | formed in view of said point, and it aims at providing the illuminating device which improves the light quantity of the wavelength conversion light wavelength-converted by the wavelength conversion member, and can obtain bright illumination.

One aspect of the lighting device of the present invention is:
In an illumination device having a primary light source unit and a light conversion unit unit,
The primary light source unit has a primary light emitting end for emitting primary light,
The light conversion unit is
A light conversion member that converts the primary light into desired secondary light;
A light transmission part having a function of transmitting the primary light and the secondary light;
A holding member having a through-hole having a function of holding the light transmitting portion therein;
Have
The incident portion which is one end of the through hole of the holding member is provided with the primary light emitting end in the vicinity thereof,
The primary light emitting end is separated from the light conversion member, and the light conversion member is separated from the holding member;
The light transmission part is at least partially installed in the gap between the primary light emission end and the light conversion member, and from the incident part to the emission part which is the other end of the through hole of the holding member. Is composed continuously,
The lighting device has a function of thermally connecting the light conversion member and the holding member, and a heat conduction member having a higher thermal conductivity than the light transmission member installed in the light transmission portion. Furthermore, it is characterized by comprising.

  According to the present invention, the heat generated simultaneously when the wavelength conversion member performs wavelength conversion can be efficiently dissipated through the heat conduction member serving as a heat conduction path, so the amount of excitation light incident on the wavelength conversion member is increased. Therefore, it is possible to provide an illuminating device in which the amount of wavelength-converted light that has been wavelength-converted by the wavelength conversion member can be improved and bright illumination can be obtained.

FIG. 1A is a diagram illustrating a schematic configuration of the illumination device according to the first embodiment of the present invention, and FIG. 1B is a wavelength diagram of FIG. It is a perspective view which expands and shows a part of conversion unit, and FIG.1 (C) is a schematic diagram for demonstrating the positional relationship of a light transmissive member, a wavelength conversion member bottom face, an excitation light irradiation area, and a heat conductive member. It is. FIG. 2 is a schematic diagram for explaining another arrangement example of the heat conducting members. FIG. 3A is a diagram illustrating a schematic configuration of a lighting device according to a modification of the first embodiment of the present invention, and FIG. 3B is a diagram in which some members are not illustrated. ) Is an enlarged perspective view showing a part of the wavelength conversion unit of FIG. 3, and FIG. 3C is for explaining the positional relationship among the light transmission member, the wavelength conversion member bottom surface, the excitation light irradiation area, and the heat conduction member. FIG. FIG. 4A is a diagram showing a schematic configuration of the illumination device according to the second embodiment, and FIG. 4B is a diagram of the wavelength conversion unit of FIG. FIG. 4C is a schematic diagram for explaining the positional relationship among the light transmission member, the wavelength conversion member bottom surface, the excitation light irradiation area, and the heat conduction member. FIG. 5 is a schematic diagram for explaining the positional relationship among a light transmission member, a wavelength conversion member bottom surface, an excitation light irradiation area, and a heat conduction member in a lighting device according to a first modification of the second embodiment of the present invention. It is. FIG. 6A is a diagram illustrating a schematic configuration of a lighting device according to a second modification of the second embodiment of the present invention, and FIG. 6B is a diagram in which illustration of some members is omitted. It is a perspective view which expands and shows a part of wavelength conversion unit of 6 (A). FIG. 7A is a diagram showing a schematic configuration of the illumination device according to the third embodiment, and FIG. 7B is a diagram of the wavelength conversion unit of FIG. FIG. 7C is a schematic diagram for explaining the positional relationship among the light transmission member, the wavelength conversion member bottom surface, the excitation light irradiation area, and the heat conduction member. FIG. 8A is a diagram showing a schematic configuration of the illumination device according to the fourth embodiment, and FIG. 8B is a diagram of the wavelength conversion unit of FIG. It is a perspective view which expands and shows a part. FIG. 9 is a diagram illustrating a configuration of a conventional lighting device.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
[First Embodiment]
(Constitution)
First, the configuration of the illumination device according to the first embodiment of the present invention will be described.

  As shown in FIG. 1A, the illumination device 100 according to the first embodiment of the present invention is mainly divided into a light source unit 200 as a primary light source unit and a wavelength conversion unit unit 300. The wavelength conversion member 302 in the wavelength conversion unit section 300 is irradiated with the excitation light that is the primary light emitted from the light, and is converted into desired secondary light. Here, an example will be described in which the primary light is excitation light, the secondary light is wavelength converted light, and the wavelength conversion member 302 is used as a light conversion member, but the present invention is not limited to this. Of course.

The detailed structure of each part will be described below.
The light source unit 200 includes a semiconductor laser 202 and a fiber 204 that is a light guide member. The semiconductor laser 202 emits excitation light as primary light. The fiber 204 has a surface facing an end surface connected to the semiconductor laser 202, and in this specification, this surface is referred to as an excitation light emitting end 206. The pumping light exit end 206 has a function of emitting the pumping light guided from the semiconductor laser 202 in the normal direction, and an axis from which the pumping light is emitted from the center of the pumping light exit end 206 is an optical axis O. And That is, the excitation light emission end 206 functions as a primary light emission end that emits primary light.

  A wavelength conversion unit unit 300 is formed in front of the optical axis O of the fiber 204 that is a part of the light source unit 200, and a holding member 304, a light transmission member 306, a wavelength conversion member 302, and heat conduction are formed therein. A member 308 is installed.

  A cylindrical light transmission member 306 as shown in FIG. 1B is bonded to the excitation light exit end 206 of the fiber 204. A central axis passing through the centers of the two circular planes of the light transmitting member 306 coincides with the optical axis O. Here, among the surfaces of the light transmitting member 306, a circular plane bonded to the excitation light emitting end 206 is defined as a light transmitting member incident surface 310, and a plane facing the surface is defined as a light transmitting member emitting surface 312.

  Connected to the light transmitting member exit surface 312 is a cylindrical wavelength conversion member 302 as shown in FIG. A central axis passing through the centers of the two circular planes of the wavelength conversion member 302 coincides with the optical axis O. Here, of the surfaces of the wavelength conversion member 302, the surface connected to the light transmission member exit surface 312 is referred to as the wavelength conversion member entrance surface 314, and the surface facing the surface is referred to as the wavelength conversion member exit surface 316. The side surface of the wavelength conversion member 302 that is in contact with the wavelength conversion member incident surface 314 and the wavelength conversion member emission surface 316 is referred to as a wavelength conversion member side surface 318.

  Further, as shown in FIG. 1B, a heat conducting member 308 is connected in a thin film shape or a rectangular column shape to a part of the light transmitting member exit surface 312 other than the wavelength conversion member incident surface 314 is connected. Has been. The heat conducting member 308 is connected to a part of the wavelength conversion member side surface 318 that is a side surface of the wavelength conversion member 302, a part of the light transmission member emission surface 312, and an inner wall of a through hole 320 of the holding member 304 described later. Yes. The heat conducting member 308 is installed in a part of the region excluding the wavelength conversion member incident surface 314 from the light transmitting member exit surface 312 without covering all the regions.

  The holding member 304 has a through hole 320, and the excitation light emitting end 206, the light transmitting member 306, the wavelength converting member 302, and the heat conducting member 308 of the fiber 204 are held in the through hole 320 so as to hold them. Surrounding. The outer shape of the holding member 304 has a cylindrical shape, and has an internal structure having a cup shape, in other words, a cylindrical cavity. The through-hole 320 has a small-diameter hole and a large-diameter hole communicating with each other, and a small-diameter hole is opened at the center of the inner bottom surface (circular shape) of the holding member 304. An excitation light exit end 206 of the fiber 204 is installed near the small hole. A small-diameter hole that is one end of the through-hole 320 is an incident portion 322, and a large-diameter opening that is the other end is an emission portion 324.

  The incident portion 322 is provided with an excitation light exit end 206 of the fiber 204, followed by a light transmission member 306, a wavelength conversion member 302, and a heat conduction member 308, and the emission portion 324 has a wavelength conversion member exit surface. 316 are installed substantially coincident with each other.

  The central axis of the through hole 320 of the holding member 304 coincides with the optical axis O. Further, the inner wall of the through hole 320 and the side surface of the light transmission member 306 are bonded, and a part of the inner wall of the through hole 320 and a part of the heat conducting member 308 are also bonded.

The diameters of the respective members in the direction perpendicular to the optical axis O are in the following order of magnitude.
Excitation light exit end 206 of fiber 204 (core end of fiber 204 not shown)
<Incoming portion 322 of holding member 304
<Wavelength conversion member incident surface 314
≒ Wavelength conversion member exit surface 316
<Light transmitting member incident surface 310
≒ Light transmission member exit surface 312
≒ injection part 324 of holding member 304.

  The wavelength conversion member emission surface 316 has a small diameter with respect to the emission part 324 of the holding member 304, and the wavelength conversion member side surface 318 is not in full contact with the inner wall of the through hole 320 of the holding member 304.

  A portion of the holding member 304 that is not filled with the inside of the through hole 320 is referred to as a light transmitting portion space 326, and a region where the light transmitting portion space 326 and the light transmitting member 306 are combined is referred to as a light transmitting portion 328. That is, the through hole 320 has a function of holding the light transmission part 328 therein. The light transmission unit 328 has a function of transmitting both excitation light that is primary light and wavelength converted light that is secondary light. The excitation light exit end 206 of the fiber 204 is separated from the wavelength conversion member 302, and the wavelength conversion member 302 is separated from the holding member 304. A part of the light transmission part 328 is installed in the gap between the excitation light emission end 206 and the wavelength conversion member 302, and at least part of the light transmission part 328 is continuously formed from the incident part 322 to the emission part 324.

(Material of main components)
Here, materials of main members will be described.
The core portion (not shown) of the fiber 204 is preferably colorless transparent glass, and the light transmitting member 306 is preferably colorless transparent glass or colorless transparent resin.

  The wavelength conversion member 302 is a phosphor that converts all of the optical properties of light, such as peak wavelength, radiation angle, and spectral shape, and is obtained by uniformly dispersing inorganic powder phosphor particles in a colorless and transparent phosphor mold resin. Is desirable. The inorganic powder phosphor particles have a function of isotropically emitting visible light having a wavelength longer than that of excitation light by absorbing a short wavelength region of visible light such as ultraviolet light, blue-violet light, and blue light. . At the same time, heat is also generated.

  The heat conducting member 308 has a function of thermally connecting the wavelength conversion member 302 and the holding member 304. This heat conducting member 308 has a higher thermal conductivity than the light transmitting member 306 installed in the light transmitting portion 328, and for example, silver is desirable. This is because silver has a considerably high thermal conductivity among metals, and therefore can efficiently transfer the amount of heat generated in the wavelength conversion member 302. In addition, since it exhibits a very high reflectivity with respect to the entire visible light region, the excitation light and wavelength conversion light to be irradiated are reflected with high efficiency, and a part of the illumination light is effectively emitted from the emission unit 324 without loss. Can be injected as. In addition, a metal such as copper or aluminum, or a carbon material such as graphite, fullerene, carbon nanotube, or graphene, or a material containing them is particularly preferable because of high thermal conductivity.

  The holding member 304 is preferably made of a metal such as brass, and more desirably as the volume is larger. This is because if it is a metal, it can be manufactured at a low cost with good workability, and generally has high thermal conductivity, and quickly absorbs the amount of heat generated inside the wavelength conversion member 302 and transmitted through the heat conduction member 308. Because it can be done. Further, it is desirable that the outer surface of the holding member 304 is large. This is because the amount of heat transferred from the wavelength conversion member 302 via the heat conducting member 308 can be diffused through the outer surface of the holding member 304 into the outside air.

(Operation and function)
Next, the operation and function of the illumination device 100 according to the present embodiment will be described.

  The semiconductor laser 202 has a function of emitting light having a wavelength (= excitation light) that is efficient while the wavelength conversion member 302 performs wavelength conversion. By emitting the light in the direction of the incident end of the fiber 204, it is possible to enter the inside of a core portion (not shown) of the fiber 204 with high efficiency.

  The excitation light incident on the fiber 204 is guided in the core using the difference in refractive index between the core and cladding of the fiber 204, and almost no light is lost to the excitation light exit end 206 of the fiber 204. Communicate excitation light.

  The excitation light is emitted from the excitation light exit end 206 in a light distribution having an intensity distribution that maximizes the normal direction (= optical axis O) of the excitation light exit end 206. Excitation light emitted from the excitation light exit end 206 in front of the optical axis is incident on a light transmitting member 306 installed in front of the excitation light exit end 206 in the optical axis. At this time, it is necessary to have a function of allowing light to pass through between the fiber 204 and the light transmitting member 306 with high efficiency. Therefore, it is desirable that the core (not shown) of the fiber 204, the light transmitting member 306, and all the members for bonding them have substantially the same refractive index and have a characteristic of transmitting excitation light with high efficiency.

  Excitation light that has entered the light transmission member 306 with a certain light distribution travels through the light transmission member 306 with little absorption, and is emitted from the light transmission member exit surface 312 to the front of the optical axis. At this time, the excitation light is emitted with an in-plane distribution in which the central point of the light transmission member emission surface 312 is maximized. This excitation light enters the wavelength conversion member 302 disposed in front of the optical axis of the light transmission member 306 from the wavelength conversion member incident surface 314. At this time, the diameter of the excitation light emitting end 206 and the wavelength conversion member 302 and the thickness of the light transmission member 306 are determined so that almost all of the excitation light irradiates the wavelength conversion member incident surface 314.

Specifically, as shown in FIG. 1C, a beam spot 330 formed by excitation light emitted from the excitation light exit end 206 on a plane including the wavelength conversion member incident surface 314 is a wavelength conversion member incident surface. It is configured to be smaller than 314. Here, the beam spot 330 is defined as a region having a light intensity greater than 1 / e ² with respect to the maximum intensity of the excitation light emitted from the excitation light exit end 206 in the wavelength conversion member incident surface 314. , E is the Napier number as the base of the natural number. Further, in this beam spot 330, a region where the excitation light mainly irradiates the wavelength conversion member 302 is defined as a main excitation light irradiation region 332, and the other region is defined as a quasi-excitation light irradiation region 334. Here, the main excitation light irradiation region 332 is a circular region irradiated with a light amount of 1 / e or more with respect to the maximum intensity of the excitation light. Since light emitted from the fiber 204 connected to various light sources generally exhibits a substantially circularly symmetric light distribution with respect to the optical axis O, a region irradiated with a light quantity of 1 / e or more is the optical axis O. A circular region including

  The wavelength converting member 302 has a function of transmitting or scattering a part of the light into a light having a wavelength different from that of the excitation light (that is, a wavelength converted light), a part of the light into heat, and the other when the excitation light is incident on the inside thereof. Have Accordingly, almost all of the excitation light emitted in front of the optical axis enters the wavelength conversion member 302 from the wavelength conversion member incident surface 314. These excitation lights are scattered and transmitted while converting their energy into wavelength conversion light and heat, and almost all of the excitation light is converted before exiting from the wavelength conversion member exit surface 316. The wavelength conversion member 302 determines the thickness and the concentration of the wavelength conversion function so as to have such excitation light transmittance.

(Movement of wavelength conversion light)
Here, the movement of the wavelength converted light will be described.
The wavelength-converted light that has been wavelength-converted inside the wavelength conversion member 302 mainly (1) partly reaches the incident part 322, (2) partly reaches the inner wall of the holding member 304, and (3) partly. Is absorbed by the inside of the wavelength converting member 302, the light transmitting member 306, or the heat conducting member 308, and (4) part of the light reaches the emitting portion 324.

  Of these, the wavelength-converted light that has reached the incident portion 322 in (1) above is incident on the fiber 204, is guided through a core portion (not shown) of the fiber 204, and is almost absorbed inside the semiconductor laser 202 and the like.

  Further, the wavelength-converted light that has reached the inner wall of the holding member 304 in (2) is partially reflected by the wavelength-converted light reflecting function of the inner wall (including the inner bottom surface) of the holding member 304, and partly the holding member. 304 is absorbed. This reflection function may be provided on the inner wall of the holding member 304 or may be provided on the side surface of the light transmission member 306. This reflection function is called a reflection layer. The wavelength-converted light reflected from the reflective layer repeats any one of the above (1) to (4). At this time, since the diameter of the wavelength conversion member 302 is smaller than the diameter of the light transmission member 306, a space (see FIG. 3) between the inner wall of the through hole 320 of the holding member 304 and the wavelength conversion member 302 is viewed from the excitation light emission end 206 side. That is, there is a light transmitting portion space 326). Therefore, all the wavelength converted light reflected by the reflective layer does not re-enter the wavelength converting member 302 from the wavelength converting member incident surface 314, but from a portion in contact with the light transmitting portion space 326 of the light transmitting member exit surface 312. The wavelength-converted light (4) that is incident on the light transmitting portion space 326 and is emitted to the outside from the emitting portion 324 is present at a constant rate. This ratio increases as the difference between the diameter of the light transmitting member 306 (≈the inner wall diameter of the through hole 320 ≈the diameter of the emission portion 324) and the diameter of the wavelength conversion member 302 increases.

  As disclosed in Patent Document 1, conventionally, the excitation light emission end and the wavelength conversion member (940) are in contact with each other or close to each other, and the entire emission part is almost entirely covered with the wavelength conversion member. The structure is common. However, in the case of such a structure, when the wavelength converted light is effectively emitted as illumination light from the emitting portion, it must pass through the wavelength converting member. However, a general wavelength conversion member such as inorganic powder fluorescent particles has a characteristic of absorbing or scattering wavelength-converted light that has been wavelength-converted by itself. For this reason, it absorbs part of the wavelength-converted light that has been wavelength-converted by itself or scatters the light that is originally output to the outside, so it is not easily emitted from the emitting part and is converted into heat during that time. As a result, the amount of wavelength-converted light emitted to the outside is reduced. Further, when the excitation light exit end and the wavelength conversion member are in contact with each other, the region where the wavelength is converted inside the wavelength conversion member becomes considerably small, and heat is generated locally from that portion. For this reason, only a small region of the wavelength conversion member in the vicinity of the excitation light emission end becomes high temperature and deteriorates, and therefore, only low output can be input for safety reasons.

  In addition, it is important that the heat conducting member 308 is installed in a part of the region excluding the wavelength conversion member incident surface 314 from the light transmitting member exit surface 312 without covering all the regions. This is because if there is a member that absorbs or scatters visible light between the reflective layer and the emission part 324, the amount of illumination light from the emission part 324 decreases. Therefore, it is desirable to manufacture the heat conducting member 308 with as small an area as possible.

  Further, the wavelength conversion light absorbed by the inside of the wavelength conversion member 302 of the above (3), the light transmission member 306, or the heat conduction member 308 is transmitted to the wavelength conversion member 302, the light transmission member 306, and the heat conduction member 308. It is converted into heat inside each member by the absorption function for the wavelength-converted light. In particular, the wavelength converting member 302 has many materials having a function of partially absorbing wavelength converted light. Therefore, the amount of light absorbed in the wavelength conversion member 302 in the wavelength conversion light (3) is present at a constant rate. The wavelength conversion light generated inside the wavelength conversion member 302 or the wavelength conversion light incident from the wavelength conversion member incident surface 314 and the wavelength conversion member side surface 318 is absorbed at a constant rate.

  Further, the wavelength-converted light reaching the emission part 324 in (4) is effectively emitted to the outside as illumination light that passes through the emission part 324 and illuminates the object or the like.

(Movement of heat)
Next, the movement of heat will be described.
The heat converted inside the wavelength conversion member 302 is diffused to each member in contact with the wavelength conversion member 302. The diffusion route is mainly
(1) Wavelength converting member 302 → light transmitting part space 326 → external space (2) Wavelength converting member 302 → light transmitting part space 326 → holding member 304 → external space (3) Wavelength converting member 302 → external space (4) Wavelength Conversion member 302 → heat conduction member 308 → holding member 304 → external space (5) Wavelength conversion member 302 → light transmission member 306 → holding member 304 → external space (6) Wavelength conversion member 302 → light transmission member 306 → fiber 204 → There are six types of external space.

  Of these, priority is given to the thermal conductivity of each member. For example, since the light transmission space 326 and the external space are filled with air, the thermal conductivity is considerably low at about 0.02 W / mK, and others are given priority. In addition, when each of the thermal conductivity of the members related to all of these orders is low with respect to the amount of heat generated in the wavelength conversion member 302, heat diffusion from the wavelength conversion member 302 is not efficiently performed, and a long time, wavelength It remains on the conversion member 302. Since the present invention relates to an illuminating device, the wavelength conversion member 302 is continuously irradiated with excitation light, and wavelength conversion light is continuously emitted from the emission unit 324. Therefore, in such a case, the heat generation amount increases, the internal temperature of the wavelength conversion member 302 rises, and the inside of the member is stabilized at a high temperature. When the temperature is as high as 300 degrees, the wavelength conversion member 302 and its peripheral members are thermally deteriorated. When the wavelength conversion member 302 and its peripheral members are thermally deteriorated, the light absorption function with respect to visible light is increased and heat generation is further promoted, leading to failure of the apparatus. Therefore, in consideration of safety, only weak excitation light can enter, resulting in a dark illumination device.

  The wavelength conversion member 302 is desirably glass (1 W / mK) or resin (0.2 W / mK) from an optical viewpoint, and its thermal conductivity is not large compared to metal or the like. Compared with them, silver used as the heat conducting member 308 is considerably large at about 420 W / mK, and therefore, the diffusion route of the above (4) is prioritized over other diffusion routes and thermally diffuses. Since the holding member 304 is also made of metal and has a large volume and surface area, even if heat continues to be incident and the heat is continuously generated, the wavelength conversion member 302 or the heat conducting member 308 holds the heat one after another without stagnation. Heat is diffused from the member 304 to the outside.

(effect)
With the structure as described above, it is possible to provide an illuminating device that creates a larger amount of emitted light than before. That is, since the light transmission part 328 exists on the side of the wavelength conversion member 302, the wavelength conversion light reflected by the reflection layer and emitted in the forward direction of the optical axis is not incident on the wavelength conversion member 302 and is emitted. The ratio of the amount of light emitted from 324 is greatly increased. If the wavelength conversion light reflected by the reflection layer and emitted in the forward direction of the optical axis is irradiated to the wavelength conversion member, the light is reduced by being absorbed by the light absorption function of the wavelength conversion member or not being directed toward the emission part due to scattering. However, since the lighting apparatus 100 according to the present embodiment avoids such a phenomenon, it is possible to create emission light of wavelength-converted light having a larger light amount than the conventional light amount with the same input excitation light amount.

  Further, since the heat generated inside the wavelength conversion member 302 can be effectively diffused by the heat conducting member 308, the wavelength conversion member 302 and its peripheral members are stabilized at a low temperature. Therefore, even if safety is taken into consideration, it is possible to input a larger amount of excitation light than in the past, and to create bright emission light of wavelength-converted light.

  Further, since the heat conducting member 308 is made of silver, it hardly absorbs light. Therefore, although it exists in the inside of the light transmission part 328, it absorbs light and hardly generates heat | fever and can produce | generate the emission light of wavelength conversion light efficiently.

  Note that the light source of the light source unit 200 is not limited to the semiconductor laser 202. For example, by using an LED, a device can be manufactured at a lower cost.

  Alternatively, the fiber 204 may not be installed, and the laser emission end of the semiconductor laser 202 may be directly set near the incident portion 322 of the holding member 304 as the excitation light emission end 206.

  Further, the shape of the through hole 320 of the holding member 304 may be a tapered conical shape. In that case, the light transmission part has a truncated cone shape.

  Furthermore, the wavelength conversion member 302 need not be a cylinder. A cone, a truncated cone, a dome shape, or a quadrangular prism may be used.

  Further, the light transmission part space 326 may be filled with a transparent material. For example, the entire light transmission part 328 may be filled with the light transmission member 306.

  Further, the light transmitting member 306 may have a function of scattering excitation light or wavelength converted light. It is important to transmit both lights to adjacent members without absorbing light.

  Further, when the heat conducting member 308 is in contact with the holding member 304 or the wavelength conversion member side surface 318, it is desirable that the heat conducting member 308 is in physical contact with the holding member 304 or the wavelength conversion member side surface 318, but this is not a limitation. This is because, when both are in physical contact with each other, heat is effectively transferred, but even if they are not in contact with each other, they are generally efficiently transferred if they are close to each other at a short distance of 50 μm or less. Because. Even if a reflective layer, an adhesive layer, an air layer or the like is interposed in the gap, it is efficiently and efficiently transmitted regardless of the material of the interposed layer. That is, the term “thermally connected” means that the contact is physically made regardless of the presence / absence of the material of the gap or is close to 50 μm or less.

  Further, the number of heat conducting members 308 is not limited to one. There may be two or more as shown in FIG. That is, at least one heat conducting member 308 may be provided, and the number may be determined according to the amount of heat generation, the heat resistant temperature, the temperature of the outer surface that must be protected in the use environment, and the like. In addition, when providing two or more, it is preferable to arrange | position diagonally or equidistantly.

[Modification]
Next, a modification of this embodiment will be described.
As shown in FIGS. 3A to 3C, the heat conducting member 308 is formed integrally with the wavelength conversion member 302, that is, a part of the wavelength conversion member 302 is extended to the holding member 304. You may do it. This is because the inorganic powder phosphor used also as a part of the wavelength conversion member 302 has a characteristic higher than that of resin or glass of about 10 W / mk. This is because it can be diffused. In such a configuration, the wavelength conversion member 302 is not physically separated from the holding member 304, but most of the wavelength conversion member 302 contributing to heat generation is thermally separated from the holding member 304. ing.

  In the case of this configuration, the other effect is that the number of members is reduced as compared with the first embodiment and the manufacturing process is simplified. In addition, since a part of the excitation light that is not absorbed in the wavelength conversion member 302 and is scattered and reflected by the reflection layer is converted into wavelength converted light by the wavelength conversion member 302 installed as the heat conducting member 308, the excitation light Omission is reduced and wavelength converted light can be efficiently created.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
(Constitution)
The second embodiment is different from the first embodiment in the installation position of the heat conducting member 308. That is, as shown in FIGS. 4A to 4C, in the illuminating device 100 according to the second embodiment, a silver thin film is formed from the place including the optical axis center of the wavelength conversion member incident surface 314 to the holding member 304. A heat conduction member 308 is formed.

(effect)
By setting it as such a structure, the illuminating device 100 which concerns on this embodiment can enlarge the input light of excitation light. That is, the excitation light emitted from the excitation light exit end 206 of the fiber 204 is emitted most strongly in the optical axis direction, and generally tends to decrease in light quantity as it is tilted from the optical axis O. Therefore, in the case of the structure as in the present embodiment, the excitation light is strongly irradiated on the wavelength conversion member incident surface 314, and the heat conduction member 308 extends to a place where the heat generation amount is large. The amount can be thermally diffused to the holding member 304.

  Note that the excitation light directly irradiated on the heat conducting member 308 is formed into a thin film with silver, so that it is hardly converted into heat by loss, and is reflected and scattered, and a part thereof is again the wavelength converting member 302. It is possible to make an incident from another part of the light and contribute to wavelength conversion.

[First Modification]
Here, a first modification of the second embodiment will be described.
In the lighting device 100 according to the second embodiment, the heat conducting member 308 is made of silver. However, as shown in FIG. 5, the heat conducting member 308 may be made of a transparent conductor used for so-called transparent electrode applications. good. As this transparent conductor, for example, ITO (indium tin oxide), ZnO (zinc oxide), SnO (tin oxide) and the like are known. These have a relatively high thermal conductivity of 8 to 100 W / mK and are transparent.

  By using such a material as the heat conducting member 308 of the present embodiment, it is possible to prevent the excitation light from entering the wavelength conversion member 302 by the heat conducting member 308 and reduce the amount of the wavelength converted light. Can do. In addition, it is possible to prevent the wavelength conversion light from being blocked by the heat conducting member 308 to reduce the emission from the emission unit 324.

  Needless to say, such a transparent conductor may be used for the heat conducting member 308 also in the lighting device 100 according to the first embodiment.

[Second Modification]
Next, a second modification of the second embodiment will be described.
As shown in FIGS. 6A and 6B, in the lighting device 100 according to the present modification, the heat conductive member 308 using the transparent conductor as described in the first modification is emitted from the light transmitting member. It is formed on the entire surface 312.

  If the heat conducting member 308 is transparent, it is not absorbed or scattered with respect to the excitation light and the wavelength converted light, so that the thermal diffusion effect can be enhanced by increasing the thin film formation area. The highest thermal diffusion effect is to form a transparent heat conductor on the entire light transmitting member exit surface 312. In this case, since the heat conducting member 308 is transparent, it also serves as the light transmitting member 306, and the light transmitting portion 328 is continuously formed from the excitation light emitting end 206 to the emitting portion 324.

[Third Embodiment]
Next, a third embodiment of the present invention will be described.
(Constitution)
The third embodiment differs from the first embodiment in the installation position of the heat conducting member 308. That is, as shown in FIGS. 7A to 7C, in the lighting device 100 according to the third embodiment, the heat conducting member 308 is formed on a part of the light transmitting member exit surface 312, which is excitation light. Extends from the part of the peripheral edge of the main excitation light irradiation region 332, which is a region for mainly irradiating the wavelength conversion member 302, to the holding member 304 in a rectangular shape. As described above, the main excitation light irradiation region 332 is irradiated with a light amount of 1 / e or more of the excitation light amount emitted from the excitation light emission end 206 in the wavelength conversion member incident surface 314. This is a circular area. The heat conducting member 308 is arranged by forming silver from a part of the outer periphery of the circle to the outside and forming the holding member 304 with a certain width. That is, the heat conducting member 308 thermally connects the quasi-excitation light irradiation region 334 and the holding member 304.

(effect)
With such a structure, there is no member that prevents the excitation light from entering the main excitation light irradiation region 332 of the wavelength conversion member 302, so that wavelength conversion is performed efficiently and the heat conducting member 308 has a wavelength. Since the conversion member incident surface 314 extends to the outer periphery of the main excitation light irradiation region 332, heat generated mainly in the vicinity of the optical axis of the wavelength conversion member 302 can be efficiently diffused to the holding member 304.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described.
(Constitution)
The fourth embodiment is different from the first embodiment in the installation positions and shapes of the heat conducting member 308 and the light transmitting member 306. That is, as shown in FIGS. 8A and 8B, in the lighting device 100 according to the fourth embodiment, the heat conducting member 308 is held from the inside near the center in the thickness direction of the wavelength conversion member 302. Up to, it is made of rod-like or linear silver. Further, the light transmission member 306 is also filled in the light transmission portion space 326, that is, the light transmission portion 328 is entirely filled. The material of the light transmission member 306 is a transparent resin.

(effect)
The portion of the wavelength converted by the wavelength converting member 302 is mostly inside the wavelength converting member 302 close to the wavelength converting member incident surface 314, and then the conversion amount decreases exponentially as it advances in front of the optical axis. Further, both the heat generated in the wavelength converting member 302 and the wavelength converted light both start to diffuse 360 degrees isotropically. However, the wavelength converted light is likely to be scattered because the wavelength converting member 302 is installed in the direction of the emitting portion 324, and the transparent light transmitting member 306 is provided in the direction of the incident portion 322. Is injected into. On the other hand, for heat, there is a light transmission member 306 with low thermal conductivity in the direction of the incident portion 322, while a wavelength conversion member 302 with higher thermal conductivity than the light transmission member 306 is installed in front of the optical axis. It is preferentially diffused in front of the optical axis.

  Therefore, as in the present embodiment, the heat conducting member 308 is located in a place where neither the excitation light nor the wavelength converted light can easily reach by being thermally diffused from near the center in the thickness direction of the wavelength converting member 302 inside the wavelength converting member 302. Since it is installed, the heat generated inside the wavelength conversion member 302 can be efficiently transferred to the holding member 304 without substantially inhibiting the excitation light and the wavelength conversion light. For this reason, the wavelength conversion member 302 does not generate much heat, the input excitation light can be largely input, the excitation light can be efficiently converted into the wavelength conversion light, and the wavelength conversion light is emitted from the emission unit 324 to the outside. be able to.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the gist of the present invention. is there.

  For example, in all of the above-described embodiments, the example relating to the illumination device 100 in which the semiconductor laser 202 serving as the excitation light source and the wavelength conversion member 302 are combined has been described, but the present invention is not limited thereto. A primary light source and a light conversion member that converts at least part of the optical properties of the primary light emitted from the primary light source, such as peak wavelength, radiation angle, and spectral shape, and emits the secondary light are combined. If it is a light source device, it is possible to obtain the effects of the present invention. In other words, any light source device can be used as long as the safety level of the secondary light emitted from the light source device is improved as compared with the safety level when the primary light is emitted as it is. can do. For example, using a diffusion member that converts only the radiation angle among the above three optical properties as the light conversion member, the radiation angle of the laser light that is the primary light is widened, and the laser light that enters the eyes of the light source user This is suitable for a light source device that improves the safety by reducing the light density.

    DESCRIPTION OF SYMBOLS 100 ... Illuminating device, 200 ... Light source part, 202 ... Semiconductor laser, 204 ... Fiber, 206 ... Excitation light emission end, 300 ... Wavelength conversion unit part, 302 ... Wavelength conversion member, 304 ... Holding member, 306 ... Light transmission member, 308... Heat conducting member, 310. Light transmitting member incident surface, 312. Light transmitting member emitting surface, 314. Wavelength converting member incident surface, 316. Wavelength converting member emitting surface, 318. Wavelength converting member side surface, 320. 322... Incident portion, 324... Exit portion, 326... Light transmitting portion space, 328... Light transmitting portion, 330 .. beam spot, 332 .. main excitation light irradiation region, 334.

Claims (9)

In an illumination device having a primary light source unit and a light conversion unit unit,
The primary light source unit has a primary light emitting end for emitting primary light,
The light conversion unit is
A light conversion member that converts the primary light into desired secondary light;
A light transmission part having a function of transmitting the primary light and the secondary light;
A holding member having a through-hole having a function of holding the light transmitting portion therein;
Have
The incident portion which is one end of the through hole of the holding member is provided with the primary light emitting end in the vicinity thereof,
The primary light emitting end is separated from the light conversion member, and the light conversion member is separated from the holding member;
The light transmission part is at least partially installed in the gap between the primary light emission end and the light conversion member, and from the incident part to the emission part which is the other end of the through hole of the holding member. Is composed continuously,
The lighting device has a function of thermally connecting the light conversion member and the holding member, and a heat conduction member having a higher thermal conductivity than the light transmission member installed in the light transmission portion. A lighting device further comprising the lighting device. The light conversion member has a light conversion member incident surface that is separated from the primary light emission end and faces the primary light emission end, and a light conversion member side surface that is in contact with the light conversion member incident surface. And
The lighting device according to claim 1, wherein the heat conducting member thermally connects a part of a side surface of the light conversion member and the holding member.   The lighting device according to claim 1, wherein the heat conducting member thermally connects the inside of the light conversion member and the holding member.   The heat conducting member thermally connects a part of the light conversion member incident surface that is spaced apart from the primary light emitting end and faces the primary light emitting end, and the holding member. The lighting device according to claim 1, wherein   Assuming that an axis passing through the center of the primary light emission end and mainly emitting the primary light emitted from the primary light emission end is an optical axis, the heat conducting member includes the optical axis and the light. The lighting device according to claim 4, wherein a part of the light conversion member incident surface including one point where the conversion member incident surface intersects is thermally connected to the holding member.   An axis through which the primary light exiting from the primary light exit end passes through the center of the primary light exit end is defined as an optical axis, and of the light conversion member entrance surface, A region irradiated with a light amount of 1 / e or more with respect to the light amount of the primary light passing through the point passing through the optical axis is defined as a main primary light irradiation region, and the other region is defined as a quasi-primary light irradiation region. Then, the heat conduction member thermally connects the quasi-primary light irradiation region and the holding member in the light conversion member. .   The lighting device according to claim 2, 3, 5, or 6, wherein the heat conducting member is a metal, a carbon material, or a material containing any of them.   The lighting device according to claim 2, 3, 5, or 6, wherein the heat conducting member is formed integrally with the light conversion member.   The lighting device according to claim 2, wherein the heat conducting member is a transparent conductor.

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