JP2012109201A - Light-emitting device, vehicular headlight, lighting device, and laser element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase flexibility of design for a light-emitting device which utilizes as illumination light the fluorescence generated by irradiating excited light to a phosphor.SOLUTION: A headlamp 1 includes laser elements 2 for emitting laser beams, a concave mirror 9 for converging the laser beam emitted from the laser element 2, and a light-emitting section 4 for emitting fluorescence by receiving the laser beams converged by the concave mirror 9.

Description

  The present invention relates to a light-emitting device, a vehicle headlamp, and an illumination device that use fluorescence generated by irradiating a phosphor with excitation light as illumination light.

  In recent years, semiconductor light emitting devices such as light emitting diodes (LEDs) and semiconductor lasers (LDs) are used as excitation light sources, and excitation light generated from these excitation light sources is emitted to light emitting units including phosphors. Research on light-emitting devices that use fluorescence generated by the above as illumination light has become active.

  An example of such a light emitting device is a vehicular lamp disclosed in Patent Document 1. In this vehicular lamp, the semiconductor light emitting element and the phosphor are arranged apart from each other, and a condensing lens for condensing the light from the semiconductor light emitting element on the phosphor is provided between them.

  Further, in the lamp described in Patent Document 2, a phosphor is disposed inside the reflecting mirror, and excitation light is irradiated to the phosphor from the outside of the reflecting mirror through a light transmission portion provided in the reflecting mirror. In this configuration, a lens for condensing excitation light on the phosphor is provided between the semiconductor light emitting element and the phosphor and outside the reflecting mirror.

Japanese Unexamined Patent Publication No. 2004-241142 (released on August 26, 2004) JP 2005-150041 A (released on June 9, 2005)

  Patent Documents 1 and 2 disclose a configuration in which the excitation light source, the condensing lens, and the light emitting unit are linearly arranged. However, it is difficult to change the optical path in the configuration using such a condensing lens. Therefore, there arises a problem that the degree of freedom in design is low. Due to the low degree of freedom in design, for example, it becomes difficult to realize a compact light-emitting device or a light-emitting device that fits in a specific shape.

  The objective of this invention is providing the light-emitting device, the vehicle headlamp, and the illuminating device which can raise the freedom degree of design. Another object of the present invention is to simplify the structure of a light-emitting device including a laser element.

  In order to solve the above problems, a light-emitting device according to the present invention includes an excitation light source that emits excitation light, a concave mirror that collects excitation light emitted from the excitation light source, and an excitation light that is collected by the concave mirror. And a light emitting unit that emits fluorescence when receiving light.

  According to said structure, the light emission part emits fluorescence in response to the excitation light from an excitation light source, and the fluorescence is radiate | emitted as illumination light. In this configuration, the optical path of the excitation light can be changed by providing a concave mirror on the optical path of the excitation light from the excitation light source to the light emitting unit and condensing the excitation light with the concave mirror.

  Therefore, the degree of freedom in designing the light emitting device can be increased as compared with the configuration in which the excitation light is collected using only the condenser lens. As a result, for example, a compact light emitting device can be realized.

  Moreover, it is preferable that the concave mirror collects excitation light emitted from a plurality of excitation light sources.

  According to said structure, the concave mirror can condense the excitation light radiate | emitted from the several excitation light source, and can raise the power of excitation light.

  It is preferable that a plurality of concave mirrors and a plurality of excitation light sources are provided, and at least one excitation light source is associated with each concave mirror.

  According to said structure, the excitation light from a some excitation light source is each condensed with a some concave mirror. Thus, by providing a plurality of sets of excitation light sources and concave mirrors, the power of excitation light can be increased.

  Moreover, it is preferable that the plurality of concave mirrors are integrally formed.

  By forming a plurality of concave mirrors as one body, the concave mirrors can be easily manufactured and positioned.

  The light emitting unit further includes a reflecting mirror that reflects the fluorescence generated by the light emitting unit, and a part of the reflecting mirror is disposed above the upper surface of the light emitting unit having a larger area than the side surface. It is preferable that the area of the spot of the excitation light on the surface of the light emitting portion irradiated with the excitation light is smaller than the area of the surface.

  According to said structure, since the upper surface of a light emission part has opposed the reflective mirror, the ratio of the fluorescence which can control the course among the fluorescence radiate | emitted from the light emission part can be raised.

  Even in this case, there is a high possibility that the fluorescence emitted from the side surface of the phosphor (side emission fluorescence) cannot be controlled.

  However, since the light emitting portion is thin or the area of the excitation light irradiation surface is larger than the area of the excitation light spot, the side emission fluorescence is reduced. Therefore, the fluorescence that cannot be controlled by the reflecting mirror can be reduced, and the utilization efficiency of the fluorescence can be increased.

  In this specification, “the light emitting portion is thin” means the shape of the light emitting portion in which the side surface is sufficiently smaller than the upper surface of the light emitting portion, and most of the fluorescence is emitted upward.

  The apparatus further includes a reflecting mirror that reflects the fluorescence generated by the light emitting unit, the excitation light source is disposed outside the reflecting mirror, and a window that transmits or passes the excitation light is provided in the reflecting mirror. It is preferable to be provided.

  According to said structure, excitation light can be irradiated to a light emission part from the exterior of a reflective mirror through the window part provided in the reflective mirror. Therefore, the degree of freedom of arrangement of the excitation light source can be increased, and for example, the irradiation angle of the excitation light with respect to the irradiation surface of the light emitting unit can be easily set to a preferable angle.

  The window may be an opening or may have a transparent member that can transmit excitation light.

  The support member further includes a reflecting mirror having a reflection curved surface that reflects the fluorescence generated by the light emitting unit, and a support member that has a surface facing the reflection curved surface and supports the light emitting unit. An opening is formed, and the excitation light is preferably applied to the light emitting unit through the opening.

  According to said structure, the support part is arrange | positioned in the position facing the reflective curved surface of a reflective mirror, and the light emission part is supported by the said support part. The support portion is provided with an opening for irradiating the light emitting portion with excitation light.

  Therefore, it is not necessary to form an opening for transmitting excitation light to the reflecting mirror, the area of the reflecting surface of the reflecting mirror can be substantially increased, and the amount of fluorescence that can be controlled can be increased.

  Further, the reflecting mirror has, as a reflecting curved surface, at least part of a partial curved surface obtained by cutting a curved surface formed by rotating a parabola or an ellipse with a symmetry axis as a rotational axis along a plane including the rotational axis. It is preferable to include.

  According to said structure, a reflective mirror has a reflective curved surface obtained by cut | disconnecting a paraboloid or a rotation ellipsoid surface by the plane containing a rotating shaft. Therefore, the fluorescence of the light emitting unit can be efficiently projected within a narrow solid angle, and the use efficiency of the fluorescence can be further increased. In addition, a structure other than the parabola can be disposed in a portion corresponding to the remaining half of the reflecting mirror. If this structure is a plate having high thermal conductivity and the light emitting part is brought into contact, the heat of the light emitting part can be efficiently radiated.

  Moreover, it is preferable that the said supporting member has heat conductivity.

  According to said structure, the heat | fever of a light emission part can be efficiently thermally radiated with the support member which has heat conductivity.

  The excitation light source is preferably supported by the support member.

  According to said structure, an excitation light source can also be radiated with a light emission part with the support member which has thermal conductivity, and simplification of a thermal radiation mechanism can be aimed at.

  Further, the vehicle headlamp and the lighting device including the light emitting device are also included in the technical scope of the present invention.

  In order to solve the above problems, a laser element according to the present invention includes a laser chip that emits laser light and a concave mirror that controls the radiation angle of the laser light emitted from the laser chip. .

  According to said structure, the concave mirror is provided with the laser chip which radiate | emits a laser beam inside the laser element. The concave mirror controls the radiation angle of the laser light emitted from the laser chip. As a result, the laser light emitted from the laser element can have a desired radiation angle (light distribution or directivity).

  As a result, there is no need to provide another optical member for controlling the radiation angle of the laser beam, and the configuration of the light emitting device including the laser element can be simplified.

  Moreover, it is preferable that the concave mirror includes at least a part of a curved surface formed by rotating a parabola or an ellipse about the axis of symmetry as a rotation axis as a reflection curved surface.

  With the above configuration, the laser light emitted from the laser chip can be efficiently collected and controlled, and the control of the radiation angle of the laser light becomes easy.

  The light emitting point of the laser chip is preferably arranged at or near the focal position of the concave mirror.

  According to the above configuration, since the laser chip and the concave mirror are close to each other, the laser light emitted from the laser chip is condensed by the concave mirror before diverging. Further, when the light emitting point is arranged at the focal position of the concave mirror, the radiation angle of the laser light emitted from the light emitting point can be controlled with high accuracy.

  The light emitting device according to the present invention includes: (i) a laser element that includes a laser chip that emits laser light; and a concave mirror that controls a radiation angle of the laser light emitted from the laser chip; and (ii) the laser. And a light emitting portion that emits fluorescence upon receiving laser light emitted from the element.

  According to the above configuration, the laser beam emitted from the laser element can be controlled to have a desired radiation angle, and without using another optical member for controlling the radiation angle of the laser beam. Laser light can be efficiently irradiated to the light emitting unit.

  Therefore, the configuration of the light emitting device can be simplified.

  Moreover, it is preferable that the laser beam emitted from the laser element is applied to the light emitting unit without passing through an optical member.

  According to said structure, the radiation angle of a laser beam is controlled only by the concave mirror incorporated in the laser element. Therefore, the configuration of the light emitting device can be simplified and a small light emitting device can be realized.

  Further, compared to a configuration in which an optical member for controlling the laser beam emission angle is provided outside the laser element, the possibility that the relative position between the members is displaced due to an impact is reduced, so that the impact resistance of the light emitting device is improved. be able to.

  As described above, the light emitting device according to the present invention receives the excitation light source that emits the excitation light, the concave mirror that collects the excitation light emitted from the excitation light source, and the excitation light that is collected by the concave mirror. And a light emitting unit that emits fluorescence.

  Therefore, there is an effect that the degree of freedom in designing the light emitting device can be increased.

  The laser element according to the present invention includes a laser chip that emits laser light and a concave mirror that controls the radiation angle of the laser light emitted from the laser chip.

  Therefore, the configuration of the light emitting device including the laser element can be simplified.

It is sectional drawing which shows schematic structure of the headlamp which concerns on one Embodiment of this invention. It is a conceptual diagram which shows the paraboloid of a parabolic mirror. (A) is a top view of a parabolic mirror, (b) is a front view of the parabolic mirror, and (c) is a side view of the parabolic mirror. It is a figure which shows the state which irradiated the laser beam to the light emission part. It is a graph which shows the relationship between the thickness of a light emission part, and light emission characteristics. It is a figure which shows the state which irradiated the laser beam on the upper surface of the light emission part. It is a conceptual diagram which shows the light projection characteristic of a parabolic mirror. It is a figure for demonstrating the principle of the light projection characteristic of a parabolic mirror. It is a conceptual diagram which shows the arrangement | positioning direction of the headlamp in a motor vehicle. It is the schematic which shows the structure of the headlamp which concerns on one Example of this invention. It is a top view which shows the structure of the said headlamp. It is the schematic which shows the structure of the headlamp which concerns on another Example of this invention. It is the schematic which shows the structure of the headlamp which concerns on another Example of this invention. It is the schematic which shows the structure of the illuminating device which concerns on one Example of this invention. It is the schematic which shows the structure of the headlamp which concerns on another Example of this invention. It is a figure which shows the internal structure of the laser element with which the said headlamp is provided. It is a perspective view which shows the structure of the said laser element. It is a figure which shows the positional relationship of the light emission point of the laser chip with which the said laser element is provided, and the focus of a concave mirror. It is a figure which shows the optical path of the laser beam in the said laser element. It is the schematic which shows the structure of the headlamp which concerns on another Example of this invention. It is a perspective view which shows the example of a change of the said laser element. It is a perspective view which shows another example of a change of the said laser element.

  The following describes one embodiment of the present invention with reference to FIGS.

<Configuration of headlamp 1>
FIG. 1 is a cross-sectional view showing a schematic configuration of a headlamp 1 according to an embodiment of the present invention. As shown in FIG. 1, a headlamp 1 includes a laser element (excitation light source, semiconductor laser) 2, a beam shaping lens 3, a light emitting unit 4, a parabolic mirror (reflecting mirror) 5, a metal base (thermally conductive member, support member). ) 7 and fins (cooling section) 8 are provided.

(Laser element 2)
The laser element 2 is a light emitting element that functions as an excitation light source that emits excitation light. A plurality of laser elements 2 may be provided. In this case, laser light as excitation light is oscillated from each of the plurality of laser elements 2. Although only one laser element 2 may be used, it is easier to use a plurality of laser elements 2 in order to obtain a high-power laser beam.

  The laser element 2 may have one light emitting point on one chip, or may have a plurality of light emitting points on one chip. The wavelength of the laser light of the laser element 2 is, for example, 405 nm (blue purple) or 450 nm (blue), but is not limited thereto, and may be appropriately selected according to the type of phosphor included in the light emitting unit 4. .

  Moreover, it is also possible to use a light emitting diode (LED) instead of a laser element as an excitation light source (light emitting element).

(Beam shaping lens 3)
The beam shaping lens 3 is a lens for shaping the laser beam so that the laser beam emitted from the laser element 2 is irradiated to the concave mirror 9 as a circular spot. Yes.

  Usually, the laser light emitted from the laser element diverges at a wide angle (forms an elliptical spot). Therefore, in order to condense efficiently by the concave mirror 9, the radiation angle of the laser light is controlled (beam shaping). It is preferable to do. In particular, when condensing laser beams from a plurality of laser elements 2 with the concave mirror 9, it is difficult to condense them at one point unless the irradiation range of the laser beams is narrowed to some extent. For this reason, it is preferable to provide the beam shaping lens 3.

  However, the beam shaping lens 3 may be omitted when the laser element 2 and the concave mirror 9 are provided on a one-to-one basis, or when the structure of the concave mirror 9 corresponds to a plurality of spots.

(Concave mirror 9)
The concave mirror 9 is a reflecting mirror that condenses the laser light emitted from the laser element 2 and guides the laser light to the light emitting unit 4. The reflecting surface is concave.

  When the circular laser beam spot formed by the beam shaping lens 3 is irradiated on the reflecting surface of the concave mirror 9, the laser beam is reflected toward the light emitting unit 4 while being condensed. Therefore, the concave mirror 9 has a function of condensing the laser light and a function of changing the optical path of the laser light. This is a functional difference from a condensing lens having only a condensing function.

  If the beam shaping lens 3 is used as described above, it becomes easy to collect a plurality of laser beams with the concave mirror 9, but the design of the concave mirror 9 is suitable for a plurality of spots (for example, a shape having distortion). By doing so, the beam shaping lens 3 may be omitted. For example, when condensing laser beams from a plurality of laser elements 2, the concave mirror 9 may be formed as a set of micromirrors corresponding to each laser beam bundle.

  The concave mirror 9 may be a resin-molded base member with a metal coating on the surface, or may be made of a metal having a reflective surface. If the concave mirror 9 is manufactured by resin molding, a complicated shape can be manufactured easily and inexpensively. However, when the reflectance is low, the concave mirror 9 may be heated by the laser light, and thus the concave mirror 9 preferably has a high reflectance.

  In the case of manufacturing a condensing lens, it is usually formed of glass in consideration of heat resistance against the heat of laser light, and the surface thereof is coated. Therefore, the condensing lens is relatively expensive.

  The positional relationship among the laser element 2, the concave mirror 9, and the light emitting section 4 is not limited to that shown in FIG. 1, and the laser element 2 emits laser light from the upper direction to the lower direction in FIG. Alternatively, the laser beam may be reflected by the concave concave mirror 9 to irradiate the light emitting unit 4.

(Light emitting part 4)
The light emitting unit 4 emits fluorescence by receiving the laser light emitted from the laser element 2 and reflected by the concave mirror 9, and includes a phosphor (fluorescent substance) that emits light by receiving the laser light. Specifically, the light emitting unit 4 is one in which a phosphor is dispersed inside a sealing material, or a phosphor is solidified. The light emitting unit 4 can be said to be a wavelength conversion element because it converts laser light into fluorescence.

  The light emitting unit 4 is disposed on the metal base 7 and at a substantially focal position of the parabolic mirror 5. Therefore, the fluorescence emitted from the light emitting unit 4 is reflected on the reflection curved surface of the parabolic mirror 5 so that the optical path is controlled. An antireflection structure that prevents reflection of laser light may be formed on the upper surface of the light emitting unit 4.

  Note that the illumination light irradiation range may be intentionally expanded by disposing the light emitting unit 4 at a position shifted from the focal position.

  As the phosphor of the light emitting unit 4, for example, an oxynitride phosphor (for example, sialon phosphor) or a III-V group compound semiconductor nanoparticle phosphor (for example, indium phosphorus: InP) can be used. These phosphors have high heat resistance against high-power (and / or light density) laser light emitted from the laser element 2, and are optimal for laser illumination light sources. However, the phosphor of the light emitting unit 4 is not limited to the above-described phosphor, and may be another phosphor such as a nitride phosphor.

  In addition, the law stipulates that the illumination light of the headlamp must be white having a predetermined range of chromaticity. For this reason, the light emitting unit 4 includes a phosphor selected so that the illumination light is white.

  For example, when blue, green, and red phosphors are included in the light emitting unit 4 and irradiated with laser light of 405 nm, white light is generated. Alternatively, a yellow phosphor (or green and red phosphor) is included in the light-emitting portion 4, and a so-called blue laser having a peak wavelength in a wavelength range of 450 nm (blue) to 450 nm (blue) or 440 nm to 490 nm. White light can also be obtained by irradiating light.

  The sealing material of the light emitting unit 4 is, for example, a resin material such as a glass material (inorganic glass or organic-inorganic hybrid glass) or a silicone resin. Low melting glass may be used as the glass material. The sealing material is preferably highly transparent, and when the laser beam has a high output, a material having high heat resistance is preferable.

(Parabolic mirror 5)
The parabolic mirror 5 reflects the fluorescence generated by the light emitting unit 4 and forms a light bundle (illumination light) that travels within a predetermined solid angle. The parabolic mirror 5 may be, for example, a member having a metal thin film formed on the surface thereof or a metal member.

  2 is a conceptual diagram showing a paraboloid of the parabolic mirror 5, FIG. 3 (a) is a top view of the parabolic mirror 5, (b) is a front view, and (c) is a side view. FIGS. 3A to 3C show an example in which the parabolic mirror 5 is formed by hollowing out the inside of a rectangular parallelepiped member so as to easily illustrate the drawings.

  As shown in FIG. 2, the parabolic mirror 5 is obtained by cutting a curved surface (parabolic curved surface) formed by rotating the parabola around the axis of symmetry of the parabola with a plane including the rotational axis. The partial curved surface is at least partially included in the reflecting surface. 3A and 3C, the curve indicated by reference numeral 5a indicates a parabolic surface. As shown in FIG. 3B, when the parabolic mirror 5 is viewed from the front, the opening 5b (exit of illumination light) is a semicircle.

  Part of the parabolic mirror 5 having such a shape is disposed above the upper surface of the light emitting unit 4 having a larger area than the side surface. That is, the parabolic mirror 5 is disposed at a position covering the upper surface of the light emitting unit 4. If it demonstrates from another viewpoint, a part of side surface of the light emission part 4 has faced the direction of the opening part 5b of the parabolic mirror 5. FIG.

  By making the positional relationship between the light emitting unit 4 and the parabolic mirror 5 as described above, the fluorescence of the light emitting unit 4 can be efficiently projected within a narrow solid angle, and as a result, the use efficiency of the fluorescence is increased. be able to.

  The laser element 2 and the concave mirror 9 are arranged outside the parabolic mirror 5, and the parabolic mirror 5 is formed with a window portion 6 that transmits or passes the laser light reflected by the concave mirror 9. The window 6 may be an opening or may include a transparent member that can transmit laser light. For example, a transparent plate provided with a filter that transmits laser light and reflects white light (fluorescence of the light emitting section 4) may be provided as the window section 6. In this configuration, the fluorescence of the light emitting unit 4 can be prevented from leaking from the window unit 6.

  When a plurality of concave mirrors 9 are provided, a plurality of window portions 6 corresponding to the respective concave mirrors 9 may be provided.

  A part that is not a parabola may be included in a part of the parabola mirror 5. Moreover, the reflecting mirror included in the light emitting device of the present invention may include a parabolic mirror having a closed circular opening or a part thereof. The reflecting mirror is not limited to a parabolic mirror, and may be an elliptical mirror or a hemispherical mirror. That is, the reflecting mirror only needs to include at least a part of a curved surface formed by rotating a figure (ellipse, circle, parabola) about the rotation axis on the reflecting surface.

(Metal base 7)
The metal base 7 is a plate-like support member that supports the light emitting unit 4 and is made of metal (for example, copper or iron). Therefore, the metal base 7 has high thermal conductivity, and can efficiently dissipate the heat of the light emitting unit 4. In addition, the member which supports the light emission part 4 is not limited to what consists of metals, The member containing substances (glass, sapphire, etc.) with high heat conductivity other than a metal may be sufficient. However, it is preferable that the surface of the metal base 7 in contact with the light emitting unit 4 functions as a reflecting surface. Since the surface is a reflecting surface, the laser light incident from the upper surface of the light emitting unit 4 is converted into fluorescence, and then reflected by the reflecting surface and can be directed to the parabolic mirror 5. Alternatively, the laser light incident from the upper surface of the light emitting unit 4 can be reflected by the reflecting surface and again directed to the inside of the light emitting unit 4 to be converted into fluorescence.

  Since the metal base 7 is covered with the parabolic mirror 5, it can be said that the metal base 7 has a surface facing the reflection curved surface (parabolic curved surface) of the parabolic mirror 5. It is preferable that the surface of the metal base 7 on the side where the light emitting unit 4 is provided is substantially parallel to the rotation axis of the paraboloid of the parabolic mirror 5 and substantially includes the rotation axis.

(Fin 8)
The fin 8 functions as a cooling unit (heat dissipation mechanism) that cools the metal base 7. The fin 8 has a plurality of heat radiating plates, and increases the heat radiation efficiency by increasing the contact area with the atmosphere. The cooling unit that cools the metal base 7 may have a cooling (heat dissipation) function, and may be a heat pipe, a water cooling method, or an air cooling method as described later.

<Shape of the light emitting part 4>
(Thickness of the light emitting part 4)
FIG. 4 is a diagram illustrating a state in which the light emitting unit 4 is irradiated with laser light. FIG. 4 shows a cylindrical light emitting unit 4. The light emitting unit 4 has an upper surface 4 a that mainly receives laser light, and the distance between the upper surface 4 a and the bottom surface that is the opposite surface is the thickness of the light emitting unit 4. The light emitting part 4 is preferably thin. In other words, it is preferable that the area of the side surface 4b of the light emitting unit 4 is small. “The light emitting portion is thin” means a shape of the light emitting portion in which the area of the side surface is sufficiently smaller than the upper surface of the light emitting portion, and most of the fluorescence is emitted upward (that is, from the upper surface). The reason why the light emitting portion 4 is preferably thin will be described next.

  FIG. 5 is a graph showing the relationship between the thickness of the light emitting section 4 having a diameter of 2 mm and the light emission characteristics. As shown in FIG. 5, when the light emitting unit 4 is thin (for example, when the thickness is 0.2 mm), the area of the side surface 4 b is small, so that most of the fluorescence goes out directly above the light emitting unit 4. In addition, there is almost no fluorescence emission in the direction of 90 ° (θ = ± 90 °) from the vertical line standing on the upper surface 4a of the light emitting section 4, and the fluorescence distribution is Lambertian distribution (cosine θ shown by a solid line in the graph of FIG. 5). Distribution).

  On the other hand, when the light emitting portion 4 is thick (for example, when the thickness is 1.0 mm), fluorescence emission is generated in the direction of 90 ° (θ = ± 90 °) from the perpendicular standing on the upper surface 4a of the light emitting portion 4. The fluorescence distribution is not a Lambertian distribution. That is, the ratio of the fluorescence emitted from the side surface 4b of the light emitting unit 4 is increased.

  A part of the fluorescence emitted from the side surface 4b of the light emitting unit 4 does not strike the parabolic mirror 5, but is emitted from the opening 5b of the parabolic mirror 5 and scattered in the space (see FIG. 8). Therefore, when the ratio of the fluorescence emitted from the side surface 4b of the light emitting unit 4 increases, the fluorescence that cannot be controlled by the parabolic mirror 5 increases, and the fluorescence utilization efficiency (and the laser light utilization efficiency) decreases.

  Therefore, by reducing the thickness of the light emitting unit 4, the ratio of fluorescence that cannot be controlled by the parabolic mirror 5 can be reduced, and the use efficiency of fluorescence can be increased.

  As shown in FIG. 5, when the diameter of the light emitting part 4 is fixed to 2 mm and the thickness is gradually reduced from 1.0 to 0.2 mm, when the thickness becomes 0.2 mm or less, The fluorescence distribution is a Lambertian distribution.

  Therefore, it is preferable that the thickness of the light emitting unit 4 is equal to or less than 1/10 of the maximum width among the widths when the light emitting unit 4 is viewed from a direction (side surface) perpendicular to the thickness direction. When the light emitting unit 4 is a cylinder, the maximum width is a diameter. When the light emitting unit 4 is a rectangular parallelepiped, the maximum width is a diagonal line of the upper surface (rectangle) of the light emitting unit 4.

  In addition, when the light emission part 4 is too thin, sufficient light quantity as illumination light may not be obtained. Therefore, the lower limit value of the thickness of the light emitting unit 4 is the minimum thickness value at which a desired amount of light can be obtained. Speaking of extreme theory, the lower limit of the thickness of the light emitting portion 4 is a thickness in which at least one phosphor layer exists, and is, for example, 10 μm. In addition, the upper limit (absolute value) of the thickness of the light emitting unit 4 is preferably determined in consideration of the heat dissipation efficiency of the light emitting unit 4. This is because when the thickness of the light emitting portion 4 is increased, the heat radiation efficiency in the portion opposite to the side in contact with the metal base 7 is lowered.

(Area of laser light irradiation surface of light emitting unit 4)
In order to change the fluorescence distribution of the light emitting unit 4 to Lambertian distribution, the laser light irradiation surface (upper surface 4a or bottom surface) of the light emitting unit 4 irradiated with laser light was irradiated in addition to making the light emitting unit 4 thinner. The area of the laser light spot may be smaller than the area of the laser light irradiation surface. That is, by exciting a part of the light emitting unit 4 (near the center) with laser light, the fluorescence distribution of the light emitting unit 4 can be a Lambertian distribution.

  FIG. 6 is a diagram showing a laser beam spot 4 c irradiated on the upper surface 4 a of the light emitting unit 4. As shown in FIG. 6, by making the area of the upper surface 4 a larger than the area of the laser beam spot 4 c, the fluorescence distribution of the light emitting part 4 becomes a Lambertian distribution regardless of the thickness of the light emitting part 4. This is considered to be because the fluorescence traveling to the side of the light emitting unit 4 is not emitted from the side surface of the light emitting unit 4 as a result of being diffused inside the light emitting unit 4 while traveling.

  The ratio of the area of the laser light spot to the area of the laser light irradiation surface should be small so that the laser light does not leak from the side surface of the light emitting unit 4. There is no particular upper limit on the area of the laser light irradiation surface.

<Light projection characteristics of parabolic mirror 5>
FIG. 7 is a conceptual diagram showing the light projection characteristics of the parabolic mirror 5. As shown in FIG. 7, when the headlamp 1 is arranged with the metal base 7 facing downward, most of the fluorescence (indicated by reference numeral 30) that cannot be controlled by the parabolic mirror 5 is emitted upward. The inventors of the present invention have found that almost no light is emitted in the direction.

  FIG. 8 is a diagram for explaining the principle of the light projection characteristics of the parabolic mirror 5. As shown in FIG. 8, the fluorescence (indicated by reference numeral 31) emitted from the upper surface of the light emitting unit 4 and reflected by the parabolic mirror 5 is emitted forward within a narrow solid angle.

  On the other hand, a part of the fluorescence (indicated by reference numeral 30) emitted from the side surface of the light emitting unit 4 is emitted from the predetermined solid angle and obliquely upward without hitting the parabolic mirror 5. Further, the fluorescence emitted in parallel to the surface of the metal base 7 from the side surface of the light emitting unit 4 is emitted as parallel light to the front. Therefore, the fluorescence that cannot be controlled by the parabolic mirror 5 is hardly emitted downward in the headlamp 1. If this projection characteristic is used, the parabolic mirror 5 side of the headlamp 1 can be illuminated using fluorescence that cannot be controlled by the parabolic mirror 5.

<Method of disposing headlamp 1>
FIG. 9 is a conceptual diagram showing the direction in which the headlamp 1 is disposed when the headlamp 1 is applied to a headlamp of an automobile (vehicle) 10. As shown in FIG. 9, the headlamp 1 may be disposed on the head of the automobile 10 such that the parabolic mirror 5 is positioned vertically downward. In this arrangement method, the front surface of the automobile 10 is illuminated sufficiently brightly, and the front lower side of the automobile 10 is also brightened due to the light projection characteristics of the parabolic mirror 5 described above.

  Thus, the vehicle of this invention is a vehicle provided with the vehicle headlamp. The vehicle headlamp includes an excitation light source that emits excitation light, a concave mirror that condenses the excitation light emitted from the excitation light source, and a light emitting unit that emits fluorescence by receiving the excitation light collected by the concave mirror And a reflecting mirror having a reflecting curved surface that reflects the fluorescence generated by the light emitting unit, and a support member that has a surface facing the reflecting curved surface and supports the light emitting unit. The vehicle headlamp is disposed in the vehicle such that the reflection curved surface is positioned vertically downward.

  The headlamp 1 may be applied to a traveling headlamp (high beam) for an automobile, or may be applied to a passing headlamp (low beam).

<Application example of the present invention>
The light emitting device of the present invention may be applied not only to a vehicle headlamp but also to other lighting devices. A downlight can be mentioned as an example of the illuminating device of this invention. A downlight is a lighting device installed on the ceiling of a structure such as a house or a vehicle. In addition, the lighting device of the present invention may be realized as a headlamp of a moving object other than a vehicle (for example, a human, a ship, an aircraft, a submersible, a rocket, etc.), or other than a searchlight, a projector, or a downlight. It may be realized as an indoor lighting fixture (such as a stand lamp).

  Next, a more specific embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the member similar to the member in the above-mentioned embodiment, and the description is abbreviate | omitted. Moreover, the material, shape, and various numerical values described here are merely examples, and do not limit the present invention.

[Example 1]
FIG. 10 is a schematic view showing a headlamp 21 according to an embodiment of the present invention. As shown in FIG. 10, the headlamp 21 includes a laser element 2, a concave mirror 91, a light emitting unit 4, a parabolic mirror 5, a metal base 7, and fins 8.

(Concave mirror 91)
The concave mirror 91 is an aggregate of concave mirrors having a plurality of concave mirrors 91a, and the surface of the resin concave surface is coated with aluminum. FIG. 11 is a top view showing the structure of the concave mirror 91.

  As shown in FIG. 11, the plurality of concave mirrors 91 a are arranged along the outer edge of the parabolic mirror 5 in the vicinity of the apex of the parabolic mirror 5. One laser element 2 is arranged inside each concave mirror 91 a, and the laser light emitted from the laser element 2 is condensed and reflected by the concave mirror 91 a covering the laser element 2, and is sent to the light emitting unit 4. It is irradiated. As a result, the laser beams emitted from the plurality of laser elements 2 are respectively applied to the light emitting units 4.

  The plurality of concave mirrors 91a are continuous and integrally formed. By forming a plurality of concave mirrors as a single unit in this way, the manufacturing can be facilitated because the molding can be performed once, and the positioning is facilitated as compared with the case where the plurality of concave mirrors are positioned respectively.

  However, a plurality of concave mirrors may be provided separately. In that case, in order to make the headlamp compact, it is preferable not to make the intervals between the plurality of concave mirrors meaningless.

  The concave mirror 91 shown in FIG. 11 has five concave mirrors 91a, but the number of concave mirrors 91a is not limited to five and may be set as appropriate so as to obtain a desired laser output.

  Since the laser element 2 emits laser light within a predetermined angle range (upward in FIG. 10), the concave mirror 91a moves the laser element 2 from the side surface direction (perpendicular to the optical axis of the laser light). It is not necessary to cover, and it is sufficient that the reflecting surface of the concave mirror 91a is disposed on the optical path of the laser light.

(Details of laser element 2)
The laser elements 2 have a 1 W output that emits 405 nm laser light, and are provided one by one inside the five concave mirrors 91a. Therefore, the total output of the laser beam is 5W. The laser beam emitted from the laser element 2 is applied to the concave mirror 91 without passing through the condenser lens.

  The laser element 2 is disposed on the metal base 7. Since the metal base 7 has thermal conductivity, the heat of the laser element 2 can be efficiently radiated by the metal base 7. Since the light emitting unit 4 is also disposed on the metal base 7, the heat dissipation mechanism of the laser element 2 and the heat dissipation mechanism of the light emitting unit 4 can be shared.

(Details of the light emitting unit 4)
The light emitting unit 4 is mixed with three types of RGB phosphors so as to emit white light. The red phosphor is CaAlSiN ₃ : Eu, the green phosphor is β-SiAlON: Eu, and the blue phosphor is (BaSr) MgAl ₁₀ O ₁₇ : Eu. These phosphor powders are sintered and hardened.

  The shape of the light emitting unit 4 is, for example, a disk shape having a diameter of 2 mm and a thickness of 0.1 mm.

(Details of Parabolic Mirror 5)
The opening 5b of the parabolic mirror 5 is a semicircle having a radius of 25 mm, and the depth of the parabolic mirror 5 is 45 mm. The light emitting unit 4 is disposed at the focal position of the parabolic mirror 5.

  The parabolic mirror 5 is formed with a plurality of window portions 6 corresponding to a plurality of laser beam bundles emitted from the respective laser elements 2 and condensed and reflected by the concave mirror 91.

  The position where the window portion 6 is formed (the irradiation angle of the laser beam is substantially defined thereby) is not particularly limited, but the surface of the laser beam on the surface of the light emitting portion 4 so that the reflection efficiency of the parabolic mirror 5 does not decrease. It is preferable to determine the formation position of the window portion 6 so that reflection does not increase.

(Details of metal base 7)
The metal base 7 is made of copper, and aluminum is vapor-deposited on the surface on the side where the light emitting unit 4 is disposed. On the back side, fins 8 having a length of 30 mm and a width of 1 mm are provided at intervals of 5 mm. Note that the metal base 7 and the fins 8 may be integrally formed.

(Effect of headlamp 21)
In the headlamp 21, the laser light from the laser element 2 is collected by the concave mirror 91, folded back, and applied to the light emitting unit 4. Therefore, the freedom in designing the laser beam path can be increased, and as a result, the headlamp 21 can be reduced in size.

  Further, in the headlamp 21, since the light emitting part 4 is thin and the upper surface of the light emitting part 4 faces the reflection curved surface of the parabolic mirror 5, most of the fluorescence emitted from the light emitting part 4 can be controlled by the parabolic mirror 5. . As a result, the fluorescence that cannot be controlled by the parabolic mirror 5 can be reduced, and the utilization efficiency of the fluorescence can be increased.

[Example 2]
FIG. 12 is a schematic view showing a headlamp 22 according to another embodiment of the present invention. As shown in FIG. 12, the headlamp 22 includes a set of a plurality of laser elements 2 and a beam shaping lens 3, a concave mirror 9, a light emitting unit 4, a parabolic mirror 5, a metal base 7, and fins 8.

  A major difference from the first embodiment is that a plurality of laser beams are condensed by one concave mirror, and each laser element 2 is provided with a beam shaping lens 3. The concave mirror 9 has a resin concave surface coated with aluminum as in the first embodiment.

(Details of laser element 2)
The laser element 2 emits 450 nm laser light and has 1 W output, and a total of eight laser elements are provided. Therefore, the total output of the laser beam is 8W. Two rows of four laser elements 2 are formed near the apex of the parabolic mirror 5. In FIG. 12, only two laser elements 2 are shown because the row is viewed from the lateral direction.

  The arrangement method of the laser elements 2 is not limited to the above-described one. For example, three lines each including two, three, and two laser elements 2 may be formed. In this case, a total of seven laser elements 2 are arranged. In order to prevent the laser element 2 and the laser element 2 from thermally interfering with each other, it is preferable to arrange the laser elements 2 with a certain distance therebetween.

  The laser beam emitted from the laser element 2 is shaped by the beam shaping lens 3 so that the spot when the concave mirror 9 is irradiated becomes circular. The shaped laser beam is applied to the reflecting surface of the concave mirror 9, and the irradiation range is controlled by the concave mirror 9 so that the entire light emitting unit 4 is irradiated with the laser beam.

  Further, the laser beam is irradiated at an incident angle of 45 ° with respect to the upper surface of the light emitting unit 4. Therefore, the surface reflection of the laser beam on the surface of the light emitting unit 4 can be reduced.

(Details of the light emitting unit 4)
The light emitting unit 4 includes one type of phosphor that emits yellow light. The phosphor is, for example, (Y _1-xy Gd _x Ce _y ) ₃ Al ₅ O ₁₂ (0.1 ≦ x ≦ 0.55, 0.01 ≦ y ≦ 0.4). Such a yellow phosphor powder is sintered and hardened.

  The shape of the light emitting unit 4 is, for example, a disk shape having a diameter of 2 mm and a thickness of 0.2 mm.

(Details of Parabolic Mirror 5)
The opening 5b of the parabolic mirror 5 is a semicircle having a radius of 30 mm, and the depth of the parabolic mirror 5 is 30 mm. The light emitting unit 4 is disposed at the focal position of the parabolic mirror 5 (position of 7.5 mm from the apex of the parabolic mirror 5).

  A plurality of windows 6 corresponding to the plurality of laser beam bundles reflected by the concave mirror 9 may be provided. When the plurality of laser beam bundles are close to each other, the wide window unit 6 is provided. One may be provided.

Example 3
FIG. 13 is a schematic view showing a headlamp 23 according to another embodiment of the present invention. As shown in FIG. 13, the headlamp 23 includes a set of a plurality of laser elements 2 and a condenser lens 11, a plurality of optical fibers 12, a concave mirror 9, a light emitting unit 4, a parabolic mirror 5, and a metal base 7.

  The condensing lens 11 is a lens for causing the laser light oscillated from the laser element 2 to enter an incident end which is one end of the optical fiber 12. The set of the laser element 2 and the condenser lens 11 is associated with each of the plurality of optical fibers 12 on a one-to-one basis. That is, the laser element 2 is optically coupled to the optical fiber 12 through the condenser lens 11.

  The optical fiber 12 is a light guide member that guides the laser light oscillated by the laser element 2 to the concave mirror 9. The optical fiber 12 has a two-layer structure in which the core of the core is covered with a clad having a refractive index lower than that of the core, and the laser light incident from the incident end passes through the inside of the optical fiber 12 and the other side. The light is emitted from the emission end portion 12a which is the end portion. The exit end 12a of the optical fiber 12 is bundled with a ferrule or the like.

  The laser beam emitted from the emission from the emission end 12 a of the optical fiber 12 is reflected by the concave mirror 9 to change the optical path and is condensed and irradiated to the light emitting unit 4 through the opening 7 a of the metal base 7. .

  Thus, in the headlamp 23, the opening 7 a is provided in the metal base 7, and laser light is irradiated from the bottom surface of the light emitting unit 4 through the opening 7 a.

  Therefore, it is not necessary to form the window 6 in the parabolic mirror 5, the area of the reflection curved surface of the parabolic mirror 5 can be substantially increased, and the amount of fluorescence that can be controlled can be increased.

  The material of the metal base 7 is the same as that in the first embodiment. Further, as shown in FIG. 13, the light emitting portion 4 is larger than the cross-sectional area of the opening 7a of the metal base 7, and may be arranged so as to cover the opening 7a, or substantially the same size as the opening 7a. The light emitting portion 4 may be fitted into the opening 7a.

(Details of laser element 2)
The laser element 2 emits 405 nm laser light and has a 1 W output, and a total of ten laser elements are provided. Therefore, the total output of the laser light is 10W.

  Note that only one laser element 2 may be provided, or laser light from a plurality of laser elements 2 may be irradiated to the concave mirror 9 via the beam shaping lens 3 without passing through the optical fiber 12. In addition, a lens may be provided in the vicinity of the emission end 12a of the optical fiber 12 to control the shape and spread of the laser light emitted from the emission end 12a.

(Details of the light emitting unit 4)
Three types of phosphors similar to those in Example 1 are uniformly mixed and applied to the resin. The shape of the light emitting portion 4 is a disk shape having a diameter of 5 mm and a thickness of 0.1 mm. The light emitting unit 4 is irradiated with laser light as a circular spot having a diameter of 2 mm. The irradiation position of the laser beam is approximately the focal position of the parabolic mirror 5 and is approximately the center of the upper surface 4 a of the light emitting unit 4.

  Thus, since the area of the upper surface 4a of the light emitting part 4 is larger than the area of the spot of the laser light, the fluorescence emitted from the side surface of the light emitting part 4 is almost eliminated. Therefore, the fluorescence that cannot be controlled by the parabolic mirror 5 can be reduced, and the utilization efficiency of the fluorescence can be increased.

(Details of concave mirror 9)
The concave mirror 9 is a metal mirror whose surface is silver-coated.

(Details of Parabolic Mirror 5)
The opening 5b of the parabolic mirror 5 is a semicircle having a radius of 30 mm, and the depth of the parabolic mirror 5 is 30 mm. The light emitting unit 4 is disposed at a substantially focal position of the parabolic mirror 5.

Example 4
FIG. 14 is a schematic view showing a light source 24 according to an embodiment of the present invention. The light source 24 includes a set of a plurality of laser elements 2 and a condenser lens 11, a plurality of optical fibers 12, a concave mirror 9, a light emitting unit 4, an elliptical mirror 51, a metal base 7, a fin 8, and a rod lens 14.

  The biggest difference from the first embodiment is that, in the light source 24, the reflecting mirror is not a parabolic mirror but an elliptical mirror (ellipsoidal mirror). The light emitting unit 4 is disposed at the first focal position of the elliptical mirror 51. The fluorescence reflected by the elliptical mirror 51 enters the incident surface 14a formed at one end of the rod lens 14, guides the inside of the rod lens 14, and the exit surface 14b formed at the other end. It is emitted from. The incident surface 14 a is disposed at the second focal position of the elliptical mirror 51.

  The rod lens 14 functions as an optical indexer, and it is possible to reduce illuminance unevenness, color unevenness, flicker, and the like by mixing the angle components of the light beam. The rod lens 14 may be cylindrical or prismatic, and may be selected in accordance with a desired spot shape of illumination light.

  Such a configuration using the rod lens 14 can be suitably used as an illumination system light source for a projector.

  Even in the configuration using the elliptical mirror 51, by condensing and reflecting the laser light by the concave mirror 9, the optical path of the laser light can be changed, and the design freedom of the light source can be increased.

Example 5
FIG. 15 is a schematic diagram showing a configuration of a headlamp (light emitting device) 25 according to still another embodiment of the present invention. The headlamp 25 includes a laser element 200 as an excitation light source, and a concave mirror corresponding to the concave mirror 9 in the above-described embodiment is provided inside the laser element 200.

(Configuration of the headlamp 25)
As shown in FIG. 15, the headlamp 25 includes a laser element (excitation light source) 200, a light emitting unit 4, a parabolic mirror 5, a metal base 7, and an inclined unit 15. Fluorescence is generated by irradiating the light emitting unit 4 with laser light emitted from the laser element 200. The generated fluorescence is reflected by the parabolic mirror 5 to control its optical path, and is emitted to the outside as illumination light.

  The laser element 200 includes a laser light emission window 209 (see FIG. 16) for emitting laser light to the outside of the laser element 200. The laser light emission window 209 is inserted into the opening of the parabolic mirror 5. ing. Laser light emitted from the laser element 200 through the laser light emission window 209 is directly applied to the light emitting unit 4 without passing through another optical member.

  Specifically, the opening of the parabolic mirror 5 is formed in the vicinity of the bottom of the parabolic mirror 5 (the connecting portion between the parabolic mirror 5 and the metal base 7 in FIG. 15). The optical axis of the laser beam of the laser element 200 is substantially parallel to the surface of the metal base 7 (the surface facing the reflection curved surface of the parabolic mirror 5).

  Therefore, when the thin light emitting unit 4 is placed on the surface of the metal base 7, the light emitting unit 4 is not efficiently irradiated with the laser light. In order to solve this problem, in the headlamp 25, the light emitting unit 4 is held by the inclined unit 15 at a predetermined angle (for example, 45 °) larger than 0 ° with respect to the optical axis of the laser light of the laser element 200. To do. With this configuration, the light emitting unit 4 is efficiently irradiated with laser light.

  That is, the inclined portion 15 functions as an angle maintaining portion that maintains the angle of the surface of the light emitting portion 4 with respect to the optical axis of the laser light of the laser element 200 at a predetermined angle.

  From another point of view, the vertical line standing on the upper surface of the light emitting unit 4 is inclined to the opposite side of the opening of the parabolic mirror 5 from the vertical line standing on the surface of the metal base 7.

  As the light emitting unit 4 is inclined as described above, the proportion of the fluorescence controlled by the parabolic mirror 5 out of the fluorescence emitted from the side surface of the light emitting unit 4 is increased. In other words, the fluorescence scattered outside without hitting the parabolic mirror 5 is reduced. Therefore, the utilization efficiency of fluorescence can be increased.

  The light emitting unit 4 may be placed on the surface of the metal base 7 without providing the inclined portion 15, and the laser beam may be irradiated obliquely from above the surface of the metal base 7.

(Configuration of laser element 200)
FIG. 16 is a diagram showing an internal configuration of the laser element 200. FIG. 17 is a perspective view showing the configuration of the laser element 200. As shown in FIGS. 16 and 17, the laser element 200 includes a laser chip 201, a concave mirror 202, a metal thin film 203, an insulating heat sink 204, a gold wire 205, a pedestal portion 206, a lead pin 207, a cap portion 208, and a laser light emission window. 209.

(Laser chip 201)
The laser chip 201 is a semiconductor element (laser diode) that emits laser light. FIG. 18 is a diagram showing the positional relationship between the light emitting point of the laser chip 201 and the focal point of the concave mirror 202. As shown in FIG. 18, the laser chip 201 includes an active layer 201b. The active layer 201b is a region where light is generated by a current supplied via a gold wire (bonding wire) 205, and the generated light is emitted from the light emitting point 201a as laser light.

  The length in the longitudinal direction of the laser chip 201 is, for example, 0.5 to 1.0 mm, the length in the width direction is, for example, 0.3 to 0.5 mm, and the height is, for example, 0.8 mm. 1 to 0.2 mm.

(Concave mirror 202)
The concave mirror 202 has a concave reflection surface, and controls the optical path and radiation angle (directivity) of the laser light by reflecting the laser light emitted from the laser chip 201 on the reflection surface.

  The concave mirror 202 includes at least a part of a curved surface formed by rotating a parabola or an ellipse about the axis of symmetry as a rotation axis, as a reflection curved surface. More specifically, the concave mirror 202 has, as a reflection curved surface, a partial curved surface obtained by cutting a curved surface formed by rotating a parabola or an ellipse about the axis of symmetry as a rotational axis along a plane including the rotational axis. ing. That is, the concave mirror 202 may be a parabolic mirror, an elliptical mirror, or a part thereof. The concave mirror 202 may be a free-form surface mirror, and the shape thereof is not particularly limited. In the free-form curved mirror, the radiation distribution can be freely controlled.

  In the example shown in FIG. 17, when the concave mirror 202 is viewed from above, the reflection curved surface of the concave mirror 202 is a semicircle. The radius of the semicircle is, for example, 0.2 to 0.4 mm.

  The material of the concave mirror 202 may be the same as that of the concave mirror 9, and is made of aluminum, for example. However, the concave mirror 202 is smaller than the concave mirror 9 because it is built (packaged) in the laser element 200. Therefore, it is preferable to select a material and a structure that can be easily manufactured as a small concave mirror.

  As shown in FIG. 18, the light emitting point 201 a of the laser chip 201 is disposed at or near the focal position of the concave mirror 202. Therefore, the laser light emitted from the light emitting point 201a is efficiently condensed by the concave mirror 202, and the radiation angle of the laser light is controlled (beam shaping).

  The laser chip 201 and the concave mirror 202 are soldered onto the metal thin film 203 deposited on the upper surface of the insulating heat sink 204. That is, the laser chip 201 and the concave mirror 202 are fixed to the common substrate surface. For this reason, the relative positional relationship between the laser chip 201 and the concave mirror 202 is maintained firmly, and the relative positional relationship is unlikely to change even when subjected to an external impact.

  When manufacturing the laser element 200, it is preferable to adjust the relative position and relative angle between the laser chip 201 and the concave mirror 202 with high accuracy. Therefore, passive alignment may be performed with high mechanical accuracy using a high-accuracy mounting apparatus. Alternatively, active alignment may be performed in which the laser chip 201 is illuminated with a minute output and the position of the concave mirror 202 is determined while monitoring the position and shape of the spot of the laser beam reflected by the concave mirror 202. The active alignment can be aligned with higher accuracy than the passive alignment.

(Other parts)
The insulating heat sink 204 is a heat radiating member that absorbs and dissipates heat generated by the laser chip 201, and is installed on the pedestal portion 206. The insulating heat sink 204 includes, for example, aluminum nitride (AlN) or silicon carbide (SiC).

  The lead pin 207 extends through the pedestal portion 206 and is electrically connected to an external power source. A drive current is supplied to the laser chip 201 via the lead pin 207 and the gold wire 205 connected to the lead pin 207.

  The lower electrode portion (anode electrode) of the laser chip 201 is electrically connected to the metal thin film 203, and the metal thin film 203 and the pedestal portion 206 are electrically connected to each other by a gold wire 205.

  Members such as the laser chip 201, the concave mirror 202, and the insulating heat sink 204 placed on the pedestal portion 206 are packaged by the pedestal portion 206 and the cap portion 208.

  A laser beam emission window 209 is formed in the cap unit 208, and the laser beam is emitted outside the laser element 200 through the laser beam emission window.

(Operational effect of the laser element 200)
FIG. 19 is a diagram showing an optical path of laser light in the laser element 200. As shown in FIG. 19, the laser light emitted from the laser chip 201 is reflected by the concave mirror 202, whereby the direction of the optical path and the radiation angle are controlled. The laser light reflected by the concave mirror 202 is transmitted through the laser light emission window 209 and emitted to the outside.

  Normally, laser light emitted from a laser chip diverges at a wide angle to form an elliptical spot. For example, an elliptical spot having a half width of 8 ° to 20 ° is formed.

  However, as shown in FIG. 18, by arranging the light emitting point 201a of the laser chip 201 in the vicinity of the focal position of the concave mirror 202, the laser light emitted from the light emitting point 201a can be condensed before diverging. The direction of the optical path and the radiation angle can be controlled efficiently.

  Therefore, the laser light emitted from the laser element 200 travels within a narrow solid angle. In other words, the radiation angle of the laser light emitted from the laser element 200 is reduced. For example, a laser beam in which 95% of energy is concentrated within an emission angle of ± 2.5 ° can be realized.

  Therefore, it is not necessary to separately provide an optical member for controlling the laser beam emission angle, and the configuration of the headlamp can be simplified. As a result, a small headlamp can be realized.

  The positions of the laser chip 201 and the concave mirror 202 are fixed with respect to the insulating heat sink 204 as a common substrate. For this reason, even if the headlamp 25 vibrates due to an external impact, the relative positional relationship between the laser chip 201 and the concave mirror 202 hardly changes. Therefore, a headlamp highly resistant to impact can be realized.

Example 6
FIG. 20 is a schematic view showing a configuration of a headlamp (light emitting device) 26 according to still another embodiment of the present invention. The headlamp 26 includes the laser element 200 as an excitation light source as in the headlamp 25, but the arrangement of the laser element 200 and the light emitting unit 4 is different from the arrangement in the headlamp 25.

  As shown in FIG. 20, in the headlamp 26, the laser element 200 is fitted in an opening formed in the metal base 7, and the light emitting point 201a is exposed in the opening. The optical axis of the laser beam of the laser element 200 is directed to the reflecting surface of the parabolic mirror 5 and is substantially perpendicular to the surface of the metal base 7.

  The light emitting unit 4 is disposed in the vicinity of the laser beam emission window 209 (that is, the laser beam emission unit) of the laser element 200. Specifically, the light emitting unit 4 is disposed on the surface of the metal base 7 facing the parabolic mirror 5 and at a position covering the opening. The laser light emitted from the laser light emission window 209 located at the opening is directly applied to the light emitting unit 4, and the generated white light is directed toward the reflection surface of the parabolic mirror 5. The white light is reflected by the parabolic mirror 5 so that the optical path is controlled and emitted to the front of the headlamp 26.

  As shown in FIG. 20, the light emitting unit 4 may be arranged so as to cover the opening larger than the cross-sectional area of the opening of the metal base 7, or emit light having substantially the same size as the opening. The part 4 may be fitted into the opening.

Example 7
In the fifth and sixth embodiments described above, one pair of the laser chip 201 and the concave mirror 202 is provided in one laser element 200, but a plurality of pairs of the laser chip 201 and the concave mirror 202 are provided in one laser element. It may be.

  FIG. 21 is a perspective view showing a modified example of the laser element. In the example shown in FIG. 21, four pairs of the laser chip 201 and the concave mirror 202 are provided in one laser element 220. When laser light is emitted from the light emission point 201a of each laser chip 201, the direction and the emission angle of the optical path of the laser light are controlled by being reflected by the corresponding concave mirror 202.

  When a plurality of pairs of the laser chip 201 and the concave mirror 202 are provided as described above, the arrangement of the concave mirror 202 so that the laser light reflected on each of the concave mirrors 202 gathers at a predetermined position (for example, the surface of the light emitting unit 4) ( In particular, the relative angle between the plurality of concave mirrors 202 is adjusted.

  For example, the surface of the metal thin film 203 on which the laser chip 201 and the concave mirror 202 are provided is concave, and the optical axis of the laser light formed by each concave mirror 202 reflecting the laser light intersects the surface of the light emitting unit 4. May be.

  By providing a plurality of pairs of the laser chip 201 and the concave mirror 202, high output laser light can be realized even when the laser output of each laser chip 201 is low.

  FIG. 22 is a perspective view showing another modified example of the laser element. As shown in FIG. 22, a laser chip 233 having a plurality of light emitting points 233a may be provided. Moreover, you may provide the concave mirror 231 in which the several concave mirror 202 was integrally formed. The concave mirror 231 has a plurality of concave surfaces 232, and a light emitting point 233a is disposed at or near the focal position of each concave surface 232.

  By providing a laser chip having a plurality of light emitting points in this way, or by forming a plurality of concave mirrors integrally, positioning becomes easier than when positioning a plurality of laser chips and concave mirrors respectively. This makes it easier to manufacture the laser element.

  The present invention is not limited to the above-described embodiments and examples, and various modifications can be made within the scope shown in the claims, and obtained by appropriately combining technical means disclosed in different examples. Such embodiments are also included in the technical scope of the present invention.

  The present invention can be applied to a light emitting device and a lighting device, particularly a headlamp for a vehicle or the like, and can improve the use efficiency of these fluorescence.

1 Headlamp (light emitting device, vehicle headlamp)
2 Laser element (excitation light source)
4 Light-emitting part 4a Upper surface 4c Spot (spot of excitation light)
5 Parabolic mirror (reflector)
6 Window 7 Metal base (thermal conductive member, support member)
7a Opening 9 Concave mirror 10 Automobile (vehicle)
21 Headlamp (light emitting device, vehicle headlamp)
22 Headlamp (light emitting device, vehicle headlamp)
23 Headlamp (light emitting device, vehicle headlamp)
24 Light source (light emitting device, lighting device)
25 Headlamp (light emitting device, vehicle headlamp)
26 Headlamp (light emitting device, vehicle headlamp)
51 Ellipsoidal mirror 91 Concave mirror 91a Concave mirror 200 Laser element 201 Laser chip 201a Light emitting point 202 Concave mirror 220 Laser element 231 Concave mirror 232 Concave surface 233 Laser chip 233a Light emitting point

Claims (17)

An excitation light source that emits excitation light;
A concave mirror that collects the excitation light emitted from the excitation light source;
A light-emitting device comprising: a light-emitting unit that emits fluorescence in response to excitation light collected by the concave mirror.   The light-emitting device according to claim 1, wherein the concave mirror collects excitation light emitted from a plurality of excitation light sources.   The light emitting device according to claim 1, further comprising a plurality of concave mirrors and a plurality of excitation light sources, wherein at least one excitation light source is associated with each concave mirror.   The light-emitting device according to claim 3, wherein the plurality of concave mirrors are integrally formed. A reflection mirror that reflects the fluorescence generated by the light emitting unit;
A part of the reflecting mirror is arranged above the upper surface of the light emitting unit, which is wider than the side surface,
The light emitting portion is thin, or the area of the spot of the excitation light on the surface of the light emitting portion irradiated with the excitation light is smaller than the area of the surface. The light emitting device according to item. A reflection mirror that reflects the fluorescence generated by the light emitting unit;
The excitation light source is disposed outside the reflecting mirror,
The light emitting device according to claim 1, wherein a window portion through which the excitation light is transmitted or passed is provided in the reflecting mirror. A reflecting mirror having a reflecting curved surface that reflects the fluorescence generated by the light emitting unit;
A support member that has a surface facing the reflection curved surface and supports the light emitting unit;
The light emitting device according to claim 1, wherein an opening is formed in the support member, and the excitation light is applied to the light emitting part through the opening. .   The reflecting mirror includes a curved surface formed by rotating a parabola or an ellipse about a symmetric axis as a rotational axis, and includes at least a part of a partial curved surface obtained by cutting the curved surface along a plane including the rotational axis as a reflective curved surface. The light-emitting device according to claim 5, wherein the light-emitting device is a light-emitting device.   The light-emitting device according to claim 7, wherein the support member has thermal conductivity.   The light-emitting device according to claim 9, wherein the excitation light source is supported by the support member.   A vehicle headlamp comprising the light-emitting device according to claim 1.   An illuminating device comprising the light emitting device according to claim 1. A laser chip that emits laser light;
A laser element comprising: a concave mirror that controls a radiation angle of laser light emitted from the laser chip.   14. The laser element according to claim 13, wherein the concave mirror includes at least a part of a curved surface formed by rotating a parabola or an ellipse with a symmetry axis as a rotation axis, as a reflecting curved surface.   15. The laser element according to claim 13, wherein the light emitting point of the laser chip is arranged at or near the focal position of the concave mirror. The laser device according to any one of claims 13 to 15,
A light emitting device comprising: a light emitting unit that emits fluorescence upon receiving laser light emitted from the laser element.   The light emitting device according to claim 16, wherein the laser light emitted from the laser element is applied to the light emitting unit without passing through an optical member.

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