JP5737861B2 - Lighting device and vehicle headlamp - Google Patents

Description

The present invention relates to an illumination device or the like that functions as a high-intensity light source.
Etc.

  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 a technique related to such a light emitting device is a lamp disclosed in Patent Document 1. In this lamp, a semiconductor laser is used as an excitation light source in order to realize a high-intensity light source. Since the laser light oscillated from the semiconductor laser is coherent light, the directivity is strong, and the laser light can be condensed and used as excitation light without waste. A light-emitting device using such a semiconductor laser as an excitation light source (referred to as an LD light-emitting device) can be suitably applied to a vehicle headlamp.

  Conventionally, research has been conducted to increase the light collection efficiency of a light emitted from a light-emitting device having a light-emitting tube such as a mercury lamp as a light source to a predetermined small-diameter region, and to prevent a reduction in light capture efficiency. . An example of a technique related to such a light emitting device is a lamp disclosed in Patent Document 2. In this lamp, the light emitting device includes a lens between the light source and the opening of the reflecting mirror that reflects the light emitted from the light source and emits the light forward. The light emitted from the light source is the lens. By transmitting the light, the light that could not be irradiated onto the predetermined small-diameter region when there is no lens can be condensed on the region.

JP 2005-150041 A (released on June 9, 2005) JP 2005-234471 A (published September 2, 2005)

  However, the lamp of Patent Document 1 includes a light emitting unit including a semiconductor light emitting element and a phosphor. However, in order to increase the utilization efficiency of light emitted from the lamp, all of the light emitted from the light emitting unit is reflected by a reflecting mirror. Is irradiated. That is, the light emitted from the light emitting unit is not used as the light emitted directly from the lamp. For this reason, in Patent Document 1, no consideration is given to improving the utilization efficiency of the light directly emitted from the light emitting portion to the front of the lamp.

  Further, it is assumed that the lamp of Patent Document 2 is used as a light source of a projection display device. In this case, it is necessary to irradiate the color wheel (small liquid crystal panel) with light from the light source. For this reason, in order to increase the light condensing efficiency, the lens included in the lamp needs to reliably collect the light on a part of the color wheel (predetermined small diameter region). The light is condensed at one point in the small diameter region or at least as parallel light.

  That is, in the lamp of Patent Document 2, it is necessary that the light emitted from the lens is at least parallel light, and it is not necessary to increase the light collection efficiency by emitting divergent light, and there is no such disclosure.

  In addition, when the light emitting device is used as a headlamp, for example, it is necessary to irradiate light in a certain range in front (a range where the user can safely confirm the front), and then the light is emitted from the light emitting device. Therefore, it is necessary to suppress the divergence of the emitted light and increase the light utilization efficiency. In Patent Document 2, no consideration is given to light use efficiency in a situation where a certain degree of divergence of emitted light is allowed.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an illumination device and a vehicle headlamp capable of improving the utilization efficiency of emitted light.

  In order to solve the above-described problems, an illumination device according to the present invention includes an excitation light source that emits excitation light, a light emitting unit that emits light by receiving excitation light emitted from the excitation light source, and an emission unit that emits light. A reflecting mirror that reflects the reflected light and a lens that bends the light emitted from the light emitting unit, and the light emitted from the reflecting mirror is irradiated onto a plane perpendicular to the optical axis of the reflecting mirror. The irradiated region is within a region satisfying the light distribution standard of the device itself and larger than the opening region of the reflecting mirror, and the lens receives the light from the light emitting unit, so that the optical axis, and A beam bundle that travels within a solid angle formed by a straight line connecting the outer edge of the irradiation region and the end of the diameter of the lens is formed.

  According to the above configuration, since the light emitting unit receives the excitation light emitted from the excitation light source and emits light, for example, a small high-intensity light source is realized without the need for a ballast for realizing discharge during light emission. can do.

  Moreover, according to the said structure, a light emission part receives the excitation light radiate | emitted from the excitation light source, light-emits, and a reflective mirror reflects the emitted light. The irradiation area where the light emitted from the reflecting mirror is irradiated on a plane perpendicular to the optical axis of the reflecting mirror is within an area satisfying the light distribution standard of the device itself and from the opening area of the reflecting mirror. Is also big. In addition, the lens that bends the light emitted from the light emitting unit receives light from the light emitting unit, so that the optical axis of the reflecting mirror and the straight line connecting the outer edge of the light irradiation region and the end of the lens diameter are connected. Forms a bundle of rays that travels within the solid angle formed by.

  Here, the light emitted from the illuminating device is irradiated only in a region that satisfies the light distribution standard of the device itself (that is, a region where the user needs to irradiate light from the viewpoint of safety, convenience, etc.). It is preferable. On the other hand, when the size of the illumination device is reduced, the opening area of the reflecting mirror is also reduced. In this case, the light emitted from the aperture region is collected at one point on a plane perpendicular to the optical axis of the reflecting mirror, or is irradiated as parallel light to a region having the same size as the aperture region. . For this reason, when considering the safety and convenience of the user, in a small illumination device such as the illumination device of the present invention, the emitted light is collected at one point or only forms parallel light. Then, since there is a possibility that the light utilization efficiency is lowered, it is preferable that the region satisfying the above-mentioned light distribution standard is larger than the opening region of the reflecting mirror.

  The illumination device of the present invention irradiates not only the light emitted from the reflecting mirror into the irradiation area but also the light transmitted through the lens into the irradiation area larger than the opening area of the reflecting mirror. be able to. In other words, the illumination device of the present invention is designed to pass through this lens even when the light emitted from the light emitting unit is not reflected by the reflecting mirror. Irradiation can be performed within the irradiation region.

  Therefore, in consideration of the small size of the lighting device of the present invention, the utilization efficiency of light emitted from the device can be improved.

  In the illuminating device according to the present invention, the light emitting unit has a light receiving surface that receives excitation light from the excitation light source, and an end portion of the diameter of the lens includes an outer edge portion of the light receiving surface and the reflecting mirror. It is preferable that it exists on the bus-line which passes along an outer edge part.

  According to the said structure, the outer edge part of a lens exists on the bus line which passes along the outer edge part of a light-receiving surface, and the outer edge part of a reflective mirror. That is, the lens is provided in an area surrounded by the bus bar, the opening area of the reflecting mirror, and the light emitting portion.

  Here, when the light emitted from the light emitting unit is emitted directly in front of the apparatus without being reflected by the reflecting mirror, the light travels in the above-described region. However, this light connects at least the straight line connecting the outer edge portion of the light receiving surface and the outer edge portion of the irradiation region, and the outer edge portion of the light receiving surface and the outer edge portion of the opening region of the reflecting mirror in the above region. When traveling in a region surrounded by a straight line, the irradiation region is not irradiated, but other regions (regions outside the irradiation region as viewed from the optical axis of the lens) are irradiated. Since the light irradiated to other areas is irradiation outside the above-mentioned irradiation areas, it is irradiation to areas that the user does not need when using the lighting apparatus, and the use of light emitted from the lighting apparatus It is a factor that reduces efficiency.

  Therefore, the lens is provided in a region surrounded by the bus bar, the opening region of the reflecting mirror, and the light emitting unit, so that the light directly irradiated from the light emitting unit to the front of the irradiation device is out of the irradiation region. Can be reliably prevented. Thereby, the utilization efficiency of the light radiate | emitted from an irradiation apparatus can be improved.

  In the illumination device according to the present invention, the lens is preferably spherical.

  According to the above configuration, the refractive index of the spherical lens is usually higher than that of the convex lens. That is, the focal length of the spherical lens is shorter than the focal length of the convex lens. For this reason, even if a spherical lens is installed closer to the light emitting part than a convex lens, this spherical lens forms a light bundle that travels the solid angle by bending the light emitted by the light emitting part. Can do. Therefore, the lens itself can be reduced in size by using a spherical lens. In addition, the size of the lens can be reduced, so that the size of the lighting device can be reduced.

  In the illumination device according to the present invention, it is preferable that an antireflection film for preventing reflection of irradiated light is provided on the surface of the lens.

  According to the above configuration, since the antireflection film is provided on the surface of the lens, it is possible to prevent the light emitted from the light emitting unit from being reflected by the lens. For this reason, it is possible to prevent the light reflected by the lens from being reflected by the reflecting mirror and irradiated outside the irradiation area.

  In the illumination device according to the present invention, the lens is preferably made of an inorganic material.

  Since the light emitting unit emits heat when irradiated with excitation light, it may transfer heat to a lens provided near the light emitting unit, and the lens may be deformed depending on its material.

  According to the said structure, since a lens consists of an inorganic material with high heat resistance, it can prevent that a lens deform | transforms with the heat | fever which the light emission part emitted. Moreover, since the heat resistance of the lens is high, the heat generated by the light emitting unit can be radiated through the lens.

  In the illuminating device according to the present invention, it is preferable that a hole centered on the optical axis is formed in the reflecting mirror.

  Usually, the irradiation device is designed such that when the light emitted from the light emitting unit is reflected by a reflecting mirror, the reflected light is irradiated onto the irradiation region. For this reason, there is a possibility that the light reflected by the reflecting mirror may be irradiated outside the irradiation region by irradiating a member (for example, a lens) in the illumination device or passing through the member.

  According to the above configuration, in the region where the hole is formed, the light emitted from the light emitting unit does not reflect, so when the hole is not formed, the light reflected by the reflecting mirror is irradiated to the lens, By passing through the lens, it is possible to prevent the light from being irradiated outside the irradiation region. For this reason, unnecessary transmission of the light reflected by the reflecting mirror to the lens can be prevented, and a decrease in light utilization efficiency can be prevented.

  In the illumination device according to the present invention, it is preferable that the hole is a surface perpendicular to the optical axis and the same size as a surface including the diameter of the lens.

  According to the above configuration, since the hole and the lens have the same size, unnecessary transmission of the light reflected by the reflecting mirror to the lens can be reliably prevented.

  A vehicle headlamp according to the present invention includes the above-described lighting device and a housing that houses the lighting device. The vehicular headlamp according to the present invention has the same effect as described above since the above-described lighting device is housed in the housing.

  As described above, the illumination device according to the present invention reflects an excitation light source that emits excitation light, a light emitting unit that emits light by receiving excitation light emitted from the excitation light source, and light emitted from the light emission unit. And a lens that bends the light emitted from the light emitting unit, and an irradiation area in which the light emitted from the reflecting mirror is irradiated on a plane perpendicular to the optical axis of the reflecting mirror. Is larger in an area that satisfies the light distribution standard of its own device and larger than the opening area of the reflecting mirror, and the lens receives the light from the light emitting unit, and thereby the optical axis and the irradiation area. This is a configuration in which a light beam traveling in a solid angle formed by a straight line connecting the outer edge of the lens and the end of the diameter of the lens is formed.

  Therefore, the lighting device of the present invention has an effect that it is possible to improve the utilization efficiency of the light emitted from the device in consideration of the small size.

It is sectional drawing which shows the structure of the headlamp which concerns on one Embodiment of this invention. It is a figure which shows the positional relationship of the emission end part and light emission part of an optical fiber with which the headlamp which concerns on one Embodiment of this invention is provided. It is sectional drawing which shows the structure of the modification of the headlamp which concerns on one Embodiment of this invention. It is a perspective view which shows the positional relationship of the modification of the radiation | emission adjustment lens with which the headlamp which concerns on one Embodiment of this invention is provided, and a light emission part. It is a figure for demonstrating whether the irradiation area | region is irradiated or not when the light radiate | emitted from the light emission part is radiate | emitted directly ahead of a headlamp when the light emission part is provided in the deep reflecting mirror. It is a figure for demonstrating the irradiation possibility of the irradiation area | region in case the light radiate | emitted from the light emission part is radiate | emitted directly ahead of a headlamp when a light emission part is provided in a shallow reflective mirror. It is a figure which shows a mode that the light radiate | emitted from the light emission part in the case where the radiation | emission adjustment lens with which the headlamp which concerns on one Embodiment of this invention is provided is a spherical lens. It is a figure which shows a mode that the light radiate | emitted from the light emission part in the case where the radiation | emission adjustment lens with which the headlamp which concerns on one Embodiment of this invention is provided is a biconvex lens. It is a figure for demonstrating the reason for providing a hole part in the headlamp which concerns on the position embodiment of this invention, (a) is a figure which shows a mode that the light radiate | emitted from the light emission part and reflected by the reflective mirror advances. (B) is a figure which shows a mode that the light reflected by the reflective mirror at the time of providing a biconvex lens ahead of the light emission part progresses. BRIEF DESCRIPTION OF THE DRAWINGS The specific structure of the semiconductor laser with which the headlamp concerning one Embodiment of this invention is provided is shown, (a) is a figure which shows the circuit diagram of a semiconductor laser typically, (b) is a figure of a semiconductor laser. It is a perspective view which shows a basic structure.

  The following describes one embodiment of the present invention with reference to FIGS. Here, a headlamp (vehicle headlamp) 1 for an automobile will be described as an example of the illumination device of the present invention. However, the lighting device of the present invention may be realized as a headlamp of a vehicle other than an automobile or a moving object (for example, a human, a ship, an aircraft, a submersible craft, a rocket), or may be realized as another lighting device. Also good. Examples of other lighting devices include a searchlight, a projector, and a home lighting device.

  The headlamp 1 may satisfy the light distribution characteristic standard of the traveling headlamp (high beam), or may satisfy the light distribution characteristic standard of the passing headlamp (low beam).

(Configuration of headlamp 1)
FIG. 1 is a cross-sectional view showing the configuration of the headlamp 1. As shown in the figure, the headlamp 1 includes a semiconductor laser array (excitation light source) 2, an aspheric lens 4, an optical fiber 5, a ferrule 6, a light emitting unit 7, a reflecting mirror 8, a transparent plate 9, a housing 10, an extension 11, An external lens 12, an emission adjusting lens (lens) 20, and a support 21 are provided. The semiconductor laser array 2, the optical fiber 5, the ferrule 6 and the light emitting unit 7 form a basic structure of the light emitting device. The light emitting device, the emission adjusting lens 20 and the reflecting mirror 8 form a basic structure of the lighting device.

  The semiconductor laser array 2 functions as an excitation light source that emits excitation light, and includes a plurality of semiconductor lasers (semiconductor laser elements) 3 on a substrate. Laser light is oscillated from each of the semiconductor lasers (excitation light sources) 3. It is not always necessary to use a plurality of semiconductor lasers 3 as the excitation light source, and only one semiconductor laser 3 may be used. However, in order to obtain a high-power laser beam, it is preferable to use a plurality of semiconductor lasers 3.

  The semiconductor laser 3 has one light emitting point in one chip, for example, oscillates a laser beam of 405 nm (blue violet), has an output of 1.0 W, an operating voltage of 5 V, and a current of 0.6 A. It is enclosed in a package with a diameter of 5.6 mm. The laser light oscillated by the semiconductor laser 3 is not limited to 405 nm, and may be any laser light having a peak wavelength in a wavelength range of 380 nm to 470 nm. If a high-quality short-wavelength semiconductor laser that oscillates laser light having a wavelength smaller than 380 nm can be manufactured, the laser light having a wavelength smaller than 380 nm is oscillated as the semiconductor laser 3 of the present embodiment. It is also possible to use a semiconductor laser designed as described above.

  The aspherical lens 4 is a lens for causing laser light (excitation light) oscillated from the semiconductor laser 3 to enter an incident end 5 b that is one end of the optical fiber 5. For example, as the aspheric lens 4, FLKN1 405 manufactured by Alps Electric can be used. The shape and material of the aspherical lens 4 are not particularly limited as long as the lens has the above function, but it is preferably a material having a high transmittance near 405 nm and a good heat resistance.

  The optical fiber 5 is a light guide member that guides the laser light oscillated by the semiconductor laser 3 to the light emitting unit 7 and is a bundle of a plurality of optical fibers. The optical fiber 5 has a plurality of incident end portions 5b that receive the laser light and a plurality of emission end portions 5a that emit the laser light incident from the incident end portion 5b. The plurality of emission end portions 5 a emit laser beams to different regions on the laser beam irradiation surface (light receiving surface) 7 a (see FIG. 2) of the light emitting unit 7. In other words, the plurality of emission end portions 5 a emit laser beams to different portions of the light emitting unit 7. The emission end portion 5a may be in contact with the laser light irradiation surface 7a or may be disposed at a slight interval.

  The optical fiber 5 has a two-layer structure in which an inner core is covered with a clad having a refractive index lower than that of the core. The core is mainly composed of quartz glass (silicon oxide) having almost no absorption loss of laser light, and the clad is composed mainly of quartz glass or a synthetic resin material having a refractive index lower than that of the core. . For example, the optical fiber 5 is made of quartz having a core diameter of 200 μm, a cladding diameter of 240 μm, and a numerical aperture NA of 0.22. However, the structure, thickness, and material of the optical fiber 5 are limited to those described above. Instead, the cross section perpendicular to the long axis direction of the optical fiber 5 may be rectangular.

  In addition, you may use what combined members other than an optical fiber, or an optical fiber and another member as a light guide member. The light guide member only needs to have at least one incident end that receives laser light oscillated by the semiconductor laser 3 and a plurality of emission ends that emit laser light incident from the incident end. For example, an incident part having at least one incident end part and an emitting part having a plurality of outgoing end parts may be formed as members different from the optical fiber, and the incident part and the outgoing part may be connected to both ends of the optical fiber. Good.

  FIG. 2 is a diagram showing a positional relationship between the emission end portion 5 a and the light emitting portion 7. As shown in the figure, the ferrule 6 holds a plurality of emission end portions 5 a of the optical fiber 5 in a predetermined pattern with respect to the laser light irradiation surface 7 a of the light emitting unit 7. In other words, the light emitting unit 7 has a laser light irradiation surface 7 a that receives the laser light from the semiconductor laser 3. The ferrule 6 may be formed with holes for inserting the emission end portion 5a in a predetermined pattern, and can be separated into an upper part and a lower part, and is formed on the upper and lower joint surfaces, respectively. The exit end portion 5a may be sandwiched by a groove.

  The ferrule 6 may be fixed to the reflecting mirror 8 by a rod-like or cylindrical member extending from the reflecting mirror 8. The material of the ferrule 6 is not specifically limited, For example, it is stainless steel. In FIG. 2, for convenience, three emission end portions 5a are shown, but the number of emission end portions 5a is not limited to three.

  The light emitting section 7 emits light upon receiving the laser light emitted from the emission end 5a, and includes a phosphor that emits light upon receiving the laser light. Specifically, the light emitting unit 7 is a phosphor in which a phosphor is dispersed inside a silicone resin as a phosphor holding substance. The ratio of silicone resin to phosphor is about 10: 1. In addition, the light emitting unit 7 may be formed by pressing a fluorescent material. The phosphor holding substance is not limited to silicone resin, and may be glass.

  The phosphor is of an oxynitride type, and blue, green and red phosphors are dispersed in a silicone resin. Since the semiconductor laser 3 oscillates 405 nm (blue-violet) laser light, white light is generated when the light emitting unit 7 is irradiated with the laser light. Therefore, it can be said that the light emitting portion 7 is a wavelength conversion material.

  The semiconductor laser 3 may oscillate a 450 nm (blue) laser beam (or a so-called “blue” laser beam having a peak wavelength in a wavelength range of 440 nm to 490 nm). The phosphor is a yellow phosphor or a mixture of a green phosphor and a red phosphor. A yellow phosphor is a phosphor that emits light having a peak wavelength in a wavelength range of 560 nm to 590 nm. The green phosphor is a phosphor that emits light having a peak wavelength in a wavelength range of 510 nm or more and 560 nm or less. The red phosphor is a phosphor that emits light having a peak wavelength in a wavelength range of 600 nm to 680 nm.

The phosphor is preferably a so-called sialon phosphor. Sialon is a substance in which a part of silicon atoms in silicon nitride is replaced with aluminum atoms and a part of nitrogen atoms is replaced with oxygen atoms. The sialon phosphor can be made by dissolving alumina (Al ₂ O ₃ ), silica (SiO ₂ ), rare earth elements, and the like in silicon nitride (Si ₃ N ₄ ).

  As another preferred example of the phosphor, a semiconductor nanoparticle phosphor using nanometer-sized particles of a III-V group compound semiconductor can also be used. One of the characteristics of semiconductor nanoparticle phosphors is that even if the same compound semiconductor (for example, indium phosphorus: InP) is used, the emission color can be changed by the quantum size effect by changing the particle diameter. is there. For example, InP emits red light when the particle size is about 3 to 4 nm. Here, the particle size was evaluated with a transmission electron microscope (TEM).

  In addition, since this phosphor is semiconductor-based, it has a short fluorescence lifetime, and can quickly radiate excitation light power as fluorescence, so that it is highly resistant to high-power excitation light. This is because the emission lifetime of the semiconductor nanoparticle phosphor is about 10 nanoseconds, which is five orders of magnitude smaller than that of a normal phosphor material having a rare earth-based emission center. Since the emission lifetime is short, absorption of excitation light and emission of fluorescence can be repeated quickly.

  As a result, high efficiency can be maintained against strong excitation light, and heat generation from the phosphor is reduced. Therefore, it is possible to further suppress the light conversion member from being deteriorated (discolored or deformed) by heat. Thereby, when using the light emitting element with a high light output as a light source, it can suppress more that the lifetime of a light-emitting device becomes short.

The shape and size of the light emitting unit 7 are, for example, a rectangular parallelepiped of 2 mm × 1 mm × 1 mm. In this case, the area of the laser light irradiation surface 7a that receives the laser light from the semiconductor laser 3 is 2 mm ² . The light distribution pattern (light distribution) of a vehicle headlamp that is legally regulated in Japan is narrow in the vertical direction and wide in the horizontal direction. By making the cross section substantially rectangular), the light distribution pattern can be easily realized. The light emitting unit 7 may not be a rectangular parallelepiped, and may be a cylinder whose laser light irradiation surface 7a is an ellipse or a circle. The diameter when the laser light irradiation surface 7a is a circle is, for example, 2 mm. Further, the laser light irradiation surface 7a is not necessarily a flat surface, and may be a curved surface. However, in order to control the reflection of the laser beam, the laser beam irradiation surface 7a is preferably a plane perpendicular to the optical axis of the laser beam.

  Moreover, as shown in FIG. 1, the light emission part 7 is being fixed to the position inside the transparent plate 9 (the side in which the output end part 5a is located) facing the output end part 5a. The method for fixing the position of the light emitting unit 7 is not limited to this method, and the position of the light emitting unit 7 may be fixed by a rod-like or cylindrical member extending from the reflecting mirror 8.

As described above, the light emitting unit 7 is irradiated with the high-power laser beam from the semiconductor laser 3, and the light emitting unit 7 can receive the laser beam. For example, the luminous flux emitted from the light emitting unit 7 is at least 1200 lm (lumen). As described above, it is possible to realize the headlamp 1 having a high luminance and a high luminous flux in which the luminance of the light emitting unit 7 is at least 80 cd (candela) / mm ² or more. Further, since the high-intensity headlamp 1 is realized, and a ballast for performing discharge for forming the emitted light is not required unlike the HID lamp, for example, a small-sized headlamp 1 is realized. be able to.

  The reflecting mirror 8 reflects the light emitted from the light emitting unit 7 to form a light beam that travels within a predetermined solid angle. That is, the reflecting mirror 8 reflects the light from the light emitting unit 7 to form a light beam that travels forward of the headlamp 1. The reflecting mirror 8 is, for example, a curved (cup-shaped) member having a metal thin film formed on the surface thereof.

  Further, as shown in FIG. 1, the irradiation area S1 where the light emitted from the reflecting mirror 8 is irradiated on a plane perpendicular to the optical axis of the reflecting mirror 8 is within the area satisfying the light distribution standard of the own apparatus. And larger than the opening area S2 of the reflecting mirror 8. That is, the light flux formed by the reflecting mirror 8 forms an irradiation area S1 within the area satisfying the light distribution standard of the headlamp 1 and larger than the opening area S2 of the reflecting mirror 8 on the vertical plane. .

  Here, the installation position of the light emitting unit 7 in the reflecting mirror 8 will be described. The central axis of the light emitting unit 7 is installed so as to substantially coincide with the optical axis (central axis) of the reflecting mirror 8. Further, when the light emitted from the light emitting unit 7 is applied to the reflecting mirror 8, the light beam formed by the reflected light is installed at a position (optical system focal position) where the light bundle is emitted into the irradiation region S1. When there are two or more optical system focal positions, the light emitting unit 7 is installed at a position closer to the ferrule 6. In the present embodiment, the diameter of the opening area S2 of the reflecting mirror is 30 mm, and the length (depth) from the opening area S2 of the reflecting mirror 8 to the bottom (area where the hole 30 is formed) is 40 mm. The light emitting section 7 is provided with the position 35 mm from the opening area S2 as the optical system focal position. That is, as the reflecting mirror 8, a reflecting mirror having a deep optical system focal position (an optical system having an optical system focal position at a position away from the opening area S2 on the bottom side) is used, so that the light is irradiated outside the irradiation area S1. Unnecessary light can be reduced.

  The transparent plate 9 is a transparent resin plate and holds the light emitting unit 7. The transparent plate 9 is preferably formed of a material that blocks the laser light from the semiconductor laser 3 and transmits white light (incoherent light) generated by converting the laser light in the light emitting unit 7. . Most of the coherent laser light is converted into incoherent white light by the light emitting unit 7. However, there may be a case where a part of the laser beam is not converted for some reason. Even in such a case, the laser beam can be prevented from leaking to the outside by blocking the laser beam with the transparent plate 9. In addition, when such an effect is not expected and the light emitting unit 7 is held by a member other than the transparent plate 9, the transparent plate 9 can be omitted.

  The housing (housing) 10 forms the main body of the headlamp 1 and houses the reflecting mirror 8 and the like. The optical fiber 5 passes through the housing 10, and the semiconductor laser array 2 is installed outside the housing 10. The semiconductor laser array 2 generates heat when the laser light is oscillated, but the semiconductor laser array 2 can be efficiently cooled by being installed outside the housing 10. Moreover, since the semiconductor laser 3 may break down, it is preferable to install it at a position where it can be easily replaced. If these points are not taken into consideration, the semiconductor laser array 2 may be accommodated in the housing 10.

  The extension 11 is provided on the front side of the reflecting mirror 8 to improve the appearance by concealing the internal structure of the headlamp 1 and enhance the sense of unity between the reflecting mirror 8 and the vehicle body. The extension 11 is also a member having a metal thin film formed on the surface thereof, like the reflecting mirror 8.

  The external lens 12 is provided in the opening of the housing 10 and seals the headlamp 1. The light generated by the light emitting unit 7 and reflected by the reflecting mirror 8 is emitted to the front of the headlamp 1 through the external lens 12.

  The emission adjusting lens 20 adjusts the emission direction of the light so that the light emitted directly from the light emitting unit 7 among the light emitted from the reflecting mirror 8 is irradiated into the irradiation region S1. . In other words, the emission adjusting lens 20 bends the light emitted from the light emitting unit 7, and receives the light from the light emitting unit 7, whereby the optical axis of the reflecting mirror 8 and the outer edge of the irradiation region S <b> 1. The beam bundle that travels within the solid angle formed by the straight line connecting the end portion and the end of the diameter of the exit adjustment lens 20 is formed. In FIG. 1, this straight line is formed by connecting the outer edge portions G and H of the irradiation region S <b> 1 and the end portions C and D of the diameter of the exit adjustment lens 20.

  In FIG. 1, the emission adjusting lens 20 is a spherical lens having a material LaSFN9 (refractive index: 1.85 to 1.89), a diameter of 6 mm, and a focal length of 2.7 to 2.8 mm. A light emitting surface 7b (refer to FIG. 2) that is the surface opposite to the irradiation surface 7a (the surface farthest from the ferrule 6 and facing the emission adjusting lens 20 among the surfaces of the light emitting unit 7 that emits white light). ) To 2.7 mm forward. That is, the emission adjusting lens 20 is installed such that the center of the light emitting surface 7b of the light emitting unit 7 is located at the focal position. The material of the emission adjusting lens 20 is not limited to this, and may be an inorganic material such as BK (borosilicate crown) 7 or a combination of inorganic glass and plastic, or an organic material such as methyl methacrylate or polycarbonate. However, in view of the heat resistance of the emission adjusting lens 20, it is preferable to select an inorganic material as the material. Since the inorganic material is excellent in heat resistance, not only can the thermal deformation of the emission adjusting lens 20 be prevented, but also the secondary that the heat generated by the light emitting unit 7 can be radiated through the emission adjusting lens 20. Effects can also be obtained.

  The emission adjusting lens 20 is not limited to a spherical lens, and may be a biconvex lens as shown in FIG. 3, for example. FIG. 3 is a cross-sectional view showing a modified example of the headlamp 1. In this case, the emission adjusting lens 20 is, for example, a biconvex lens having a material BK7, a diameter of 6 mm, and a focal length of 6.4 mm. That is, the output adjustment lens 20 that is a biconvex lens has a focal length longer than that of a spherical lens, and is thus disposed at a position away from the light emitting unit 7 (on the opening region S2 side of the reflecting mirror 8). In addition, the emission adjusting lens 20 may be a plano-convex lens having a material BK7, a diameter of 6 mm, and a focal length of 8 mm. However, since the focal length of the plano-convex lens is longer than that of the spherical lens and the biconvex lens, light is emitted from these lenses. It will be installed at a position away from the unit 7. If it can be installed near the light emitting unit 7, the size of the emission adjusting lens 20 can be reduced. Therefore, considering this point, it is preferable to install a spherical lens as the emission adjusting lens 20.

  Further, the emission adjusting lens 20 is installed so that the end of the diameter thereof is on a generatrix passing through the outer edge of the laser light irradiation surface 7 a and the outer edge of the reflecting mirror 8. In FIG. 1, the end portions C and D of the diameter of the emission adjusting lens 20 are on buses L1 and L2 passing through the outer edges E and F of the laser light irradiation surface 7a and the outer edges A and B of the opening region S2, respectively. . The reason for installing the emission adjusting lens 20 on this bus will be described later.

  Further, an antireflection film for preventing the reflection of the irradiated light is provided on the surface of the emission adjusting lens 20. As described above, in view of the heat resistance of the emission adjusting lens 20, it is preferable to select an inorganic material as the material of the antireflection film.

  When an antireflection film is not provided on the surface of the emission adjusting lens 20, the light emitted from the light emitting unit 7 is reflected by the surface of the emission adjusting lens 20 (for example, the surface facing the light emitting surface 7 b) and irradiated on the reflecting mirror 8. There is a possibility. Since the reflecting mirror 8 irradiates not only the light directly emitted from the light emitting unit 7 but also the light emitted from a member other than the light emitting unit 7 to the irradiation region S1, the adjustment becomes very complicated. Is very difficult. For this reason, in this Embodiment, the reflective mirror 8 is designed so that the irradiation area | region S1 can be irradiated with the light from the light emission part 7 at least. Therefore, in the case where the antireflection film is not provided in this design, the light emitted from the members other than the light emitting unit 7 and reflected by the reflecting mirror 8 is not always emitted into the irradiation region S1.

  On the other hand, when an antireflection film is provided on the surface of the emission adjusting lens 20, the light emitted from the light emitting portion 7 can be prevented from being reflected by the emission adjusting lens 20, so that the light reflected by the emission adjusting lens 20 is reflected. It is possible to prevent the light from being reflected by the mirror 8 and being irradiated outside the irradiation region S1. In addition, when the reflecting mirror 8 can also irradiate the irradiation region S1 with light from members other than the light emitting unit 7, it is not necessary to provide an antireflection film on the surface of the emission adjusting lens 20.

  The support 21 is fixed to the reflecting mirror 8 and supports the emission adjusting lens 20. For example, the support 21 is made of the same material as the transparent plate 9. In FIG. 1, the support 21 supports along the surface of the emission adjusting lens 20 including the end D of the diameter. The support 21 can place the emission adjusting lens 20 at the optical system focal position in the reflecting mirror 8 and is unlikely to interfere with the light reflected by the reflecting mirror 8 and the light transmitted through the emitting adjusting lens 20. It is preferable to be installed at a position. Further, the support 21 is preferably made of a material that does not hinder this light.

  The headlamp 1 may include an emission adjustment lens (lens) 20 </ b> A in which the emission adjustment lens 20 and the support 21 are integrated as shown in FIG. 4 instead of the emission adjustment lens 20. FIG. 4 is a perspective view showing the positional relationship between the emission adjusting lens 20 </ b> A and the light emitting unit 7. In the emission adjustment lens 20A, a lens having the same size as that of the emission adjustment lens 20 is formed at the center of a rectangular plate made of the same material as the emission adjustment lens 20, and the central axis thereof coincides with the central axis of the light emitting unit 7. It is provided to do. Further, the length of the emission adjustment lens 20A in the longitudinal direction is formed to be substantially the same as the optical system focal position of the reflecting mirror 8, and the emission adjustment lens 20A can be fitted into the optical system focal position. It is like that. In this case, the reflecting mirror 8 may be formed with fitting portions capable of fitting the four corners of the emission adjusting lens 20 to the optical system focal position. Note that the shape and material of the emission adjusting lens 20A are not limited to the above, and it is sufficient that the same function as that of the emission adjusting lens 20 can be achieved and a configuration that can be fitted to the reflecting mirror 8 can be realized.

  When the exit adjustment lens 20A is used, for example, when the exit adjustment lens is replaced, the exit adjustment lens 20A only needs to be fitted to the reflecting mirror 8 without adjusting the optical axis. That is, by using the emission adjusting lens 20A, it is possible to save the user's trouble at the time of lens replacement.

  The reflecting mirror 8 is formed with a hole 30 centered on the optical axis. The hole 30 is provided in order to prevent the light emitted from the light emitting unit 7 from being reflected by the reflecting mirror 8 and transmitting the reflected light through the emission adjusting lens 20. The hole 30 is a surface perpendicular to the optical axis of the reflecting mirror 8 and the same size as the surface including the diameter of the emission adjusting lens 20. In this case, unnecessary transmission of the light reflected by the reflecting mirror 8 to the emission adjusting lens 20 can be reliably prevented. The specific reason for providing the hole 30 will be described later.

(About the installation position of the emission adjusting lens 20)
Next, the installation position of the emission adjusting lens 20 will be described with reference to FIGS. That is, the reason why the emission adjusting lens 20 is installed on the straight lines L1 and L2 shown in FIG. 5 and 6 are diagrams for explaining whether or not the irradiation region S1 can be irradiated when the light emitted from the light emitting unit 7 is directly emitted in front of the headlamp. 5 and 6, the headlamp 100 includes the light emitting unit 7 and the reflecting mirror 8, and the light emitting unit 7 is irradiated with laser light, and the light converted by the light emitting unit 7 is emitted to the front of the reflecting mirror 8. It is assumed that the emission adjusting lens 20 is not provided as in the headlamp 1. 7 and 8 are diagrams showing how the light emitted from the light emitting unit 7 travels.

  FIG. 5 shows a case where the optical system focal position is inside the reflecting mirror 8 and the light emitting unit 7 is installed at that position. That is, FIG. 5 shows a case where the opening region S2 of the reflecting mirror 8 is in front of the light emitting unit 7 (the reflecting mirror 8 is deep) and the light emitting unit 7 is provided inside the reflecting mirror 8.

  The straight lines L3 and L4 in FIG. 5 pass through the outer edges E and F of the laser light irradiation surface 7a of the light emitting section 7, and the outer edges A and B of the opening area S2 of the reflecting mirror 8 and the outer edge G of the irradiation area S1. And a straight line parallel to a straight line (see FIG. 1) connecting H and H, respectively. Of the light emitted from the light emitting unit 7 and not reflected by the reflecting mirror 8, the light passing through the solid angle formed by the straight lines L3 and L4 and the optical axis La of the reflecting mirror 8 is irradiated into the irradiation region S1. On the other hand, light passing through other solid angles (solid angles formed by the straight lines L1 and L2 and straight lines L3 and L4, respectively; the region P in FIG. 5) is not irradiated into the irradiation region S1, and thus is unnecessary. Light going in any direction. That is, the straight lines L3 and L4 indicate the boundary line whether or not the irradiation area S1 is irradiated with the light emitted forward without being reflected by the reflecting mirror 8.

  FIG. 6 shows a case where the optical system focal position is outside the reflecting mirror 8 and the light emitting unit 7 is installed at that position. That is, FIG. 6 shows a case where the opening region S2 of the reflecting mirror 8 is behind the light emitting unit 7 (the reflecting mirror 8 is shallow) and the light emitting unit 7 is provided outside the reflecting mirror 8.

  In this case, since the straight lines L3 and L4 are parallel to the straight lines connecting the points A and B and the points G and H shown in FIG. 1, they are formed by the straight lines L3 and L4 and the optical axis La. The solid angle is the same as in FIG. On the other hand, the solid angle formed by the straight lines L1 and L2 and the optical axis La is larger than that in the case of FIG. Therefore, the light beam irradiated in the irradiation region S1 is the same as in FIG. 5, but the light beam not irradiated in the irradiation region S1 (light traveling in an unnecessary direction: light passing through the region Q in FIG. 6). Becomes larger than the case of FIG.

  The ratio of the light beam emitted from the light emitting unit 7 and emitted in an unnecessary direction out of the light beam directly emitted in front of the reflecting mirror 8 depends on the depth of the reflecting mirror 8. However, even if the deep reflector 8 is used for the headlamp 100 as shown in FIG. 5, the shallow reflector 8 is used for the headlamp 100 as shown in FIG. If it is, it will be about 50% to 75%. That is, the light emitted to the irradiation region S1 in the desired direction is only 25% to 75% of the light emitted from the light emitting unit 7 and directly emitted to the front of the reflecting mirror 8, This value is the utilization efficiency of light emitted from the headlamp 100. That is, in order to improve the utilization efficiency of the light emitted from the headlamp 100, it is necessary to irradiate the irradiation region S1 with the light emitted from the light emitting unit 7 that passes through the regions P and Q.

  In the headlamp 1 of the present embodiment, the emission adjusting lens 20 is installed in front of the light emitting unit 7 as described above. For this reason, as shown in FIG. 7, when the light directly emitted from the light emitting unit 7 to the front of the reflecting mirror 8 passes through the emission adjusting lens 20, the light can be irradiated into the irradiation region S1. For this reason, since the light irradiated outside irradiation region S1 can be decreased, the utilization efficiency of light can be improved. Further, when a biconvex lens is used as the emission adjusting lens 20 (see FIG. 3), the light directly emitted from the light emitting unit 7 to the front of the reflecting mirror 8 is transmitted through the emission adjusting lens 20 as shown in FIG. By doing so, the light can be irradiated into the irradiation region S1.

  Here, the headlamp 1 is reduced in size by increasing the brightness and size of the light emitting unit 7. For this reason, a lens is provided in front of the light-emitting unit 7 so that the light is condensed at one point on a plane perpendicular to the optical axis of the reflecting mirror 8, or as parallel light in an area having the same size as the opening area S2. The light passing through the regions P and Q can be reduced only by irradiating, but the light use efficiency may be lowered in consideration of the safety and convenience of the user. .

  However, the emission adjusting lens 20 satisfies the light distribution standard of the headlamp 1 by receiving and bending the light directly emitted from the light emitting unit 7 to the front of the reflecting mirror 8 without being reflected by the reflecting mirror 8. In addition, it is possible to irradiate the irradiation area S1, which is an area larger than the opening area S2 of the reflecting mirror 8. Thereby, since the headlamp 1 can reduce the light emitted in the unnecessary direction outside the irradiation region S1, the utilization efficiency of the light emitted in front of the reflecting mirror 8 can be improved.

  In the headlamp 1, for example, when the angle formed by the straight lines L1 and L2 shown in FIGS. 1 and 3 is 45 ° and the reflectance of the surface of the emission adjusting lens 20 is 5%, the light use efficiency is It is assumed that it can be improved by 15% compared to the case without the emission adjusting lens 20. In addition, when the angle formed by the straight lines L1 and L2 is 90 ° and the reflectance of the surface of the emission adjusting lens 20 is 5%, it is assumed that 30% can be improved.

  Further, by improving the light use efficiency, it is possible to realize the headlamp 1 that can obtain irradiation light brighter than the conventional one. Furthermore, since it is possible to emit light brighter than the conventional one, when emitting the irradiation light having the same brightness as that of the conventional headlamp, the light can be emitted with less power consumption than the conventional headlamp.

  Further, in the present embodiment, in order to make the light use efficiency close to 100%, as shown in FIG. 1, the deep reflecting mirror 8 is used, and the end portions C and D of the diameter of the exit adjustment lens 20 are linear. The refractive index and the installation position are adjusted so as to be on L1 and L2. By using the deep reflecting mirror 8, the distance from the light emitting portion 7 to the opening region S2 of the reflecting mirror 8 can be made sufficiently long, so that the light flux passing through the regions P and Q can be reduced. In addition, by setting the emission adjusting lens 20 between the straight lines L1 and L2, light passing through the areas P and Q can pass through the emission adjusting lens 20, so that light traveling in an unnecessary direction (irradiation area S1) Most of the light emitted outside) can be eliminated.

  Further, in the present embodiment, the light emitting unit 7 receives the laser light emitted from the semiconductor laser 3 and emits light to convert it into white light, so that the size can be sufficiently reduced. In accordance with the miniaturization of the light emitting unit 7, it is possible to reduce the size of the emission adjustment lens 20 whose diameter end is on the generatrix passing through the outer edge of the laser light irradiation surface 7 a and the outer edge of the reflecting mirror 8. . Further, due to the downsizing of the exit adjustment lens 20, even if the hole 30 is not formed in the reflector 8, the light bundle of light reflected by the reflector 8 and transmitted through the exit adjustment lens 20 is reduced. Can be reduced. In addition, when the hole part 30 is formed in the reflective mirror 8, this light beam can be decreased more reliably.

(About hole 30)
Next, a specific reason for providing the hole 30 in the headlamp 1 will be described with reference to FIG. FIG. 9 is a diagram for explaining the reason why the hole 30 is provided, and FIG. 9A is a diagram illustrating a state in which light emitted from the light emitting unit 7 and reflected by the reflecting mirror 8 travels. ) Is a diagram illustrating a state in which light reflected by the reflecting mirror 8 travels when a biconvex lens is provided in front of the light emitting unit 7.

  As shown in FIG. 9A, in the headlamp 100, the light emitted from the light emitting unit 7 is reflected by the reflecting mirror 8 and emitted forward. The reflecting mirror 8 is normally designed so that the reflected light is irradiated onto the irradiation region S1. For this reason, when the emission adjusting lens 20 is not provided, there is no member that blocks or changes the reflected light in the traveling direction of the reflected light. In the direction (so that the irradiation area S1 is irradiated).

  On the other hand, as shown in FIG. 9B, when the emission adjusting lens 20 is provided in front of the light emitting unit 7, part of the light reflected by the reflecting mirror 8 is transmitted through the emission adjusting lens 20. As a result, the light reflected by the reflecting mirror 8 that is irradiated onto the emission adjusting lens 20 has a different incident angle from the light emitted from the light emitting unit 7, and therefore after being collected except for the vicinity of the central axis. , It will diverge out of the irradiation area S1. In other words, the light reflected on the output adjustment lens 20 and reflected by the reflecting mirror 8 is light reflected in substantially the same area (a slightly smaller area) as the projection image of the output adjusting lens 20 projected on the reflecting mirror 8. When this light is transmitted through the emission adjusting lens 20, the direction is not a desired direction. This region can be said to be substantially the same region as the region occupied by the emission adjusting lens 20 in the reflecting mirror 8 (the region of the emission adjusting lens 20 occupying the entire region of the reflecting mirror 8 when the headlamp 1 is viewed from the front).

  For this reason, as shown in FIG. 1, by forming the hole 30 around the optical axis in the reflecting mirror 8, the region where the hole 30 is formed (at least a part of the occupied region) The light emitted from the light emitting unit 7 is not reflected. That is, by forming the hole 30 at the position of the reflecting mirror 8 shown in FIG. 1, the light bundle of the light reflected by the reflecting mirror 8 that is transmitted through the emission adjusting lens 20, that is, the light emitted in an unnecessary direction, is transmitted. By reducing the number, it is possible to prevent a decrease in light use efficiency in the headlamp 1. It should be noted that at least a hole for introducing the laser light into the reflecting mirror 8 is necessary, but the light bundle of light that is emitted in an unnecessary direction by passing through the emission adjusting lens 20 is the entire headlamp 1. Therefore, the hole 30 may not be provided in the headlamp 1 when the irradiation direction of this light is not considered.

  Further, in order to further improve the light utilization efficiency, the headlamp 1 may be configured so that all the light reflected by the reflecting mirror 8 does not pass through the emission adjusting lens 20. In this case, the size of the hole 30 may be at least as large as a surface perpendicular to the optical axis and including the diameter of the exit adjustment lens 20. Thereby, the light reflected by the reflecting mirror 8 is not transmitted through the emission adjusting lens 20, and unnecessary transmission to the emission adjusting lens 20 can be reliably prevented.

(Structure of semiconductor laser 3)
Next, the basic structure of the semiconductor laser 3 will be described. FIG. 10A schematically shows a circuit diagram of the semiconductor laser 3, and FIG. 10B is a perspective view showing the basic structure of the semiconductor laser 3. As shown in the figure, the semiconductor laser 3 has a configuration in which a cathode electrode 19, a substrate 18, a cladding layer 113, an active layer 111, a cladding layer 112, and an anode electrode 17 are laminated in this order.

The substrate 18 is a semiconductor substrate, and it is preferable to use GaN, sapphire, or SiC in order to obtain blue to ultraviolet excitation light for exciting the phosphor as in the present application. In general, as other examples of a substrate for a semiconductor laser, a group IV semiconductor represented by a group IV semiconductor such as Si, Ge and SiC, GaAs, GaP, InP, AlAs, GaN, InN, InSb, GaSb and AlN Group V compound semiconductors, Group II-VI compound semiconductors such as ZnTe, ZeSe, ZnS and ZnO, oxide insulators such as ZnO, Al ₂ O ₃ , SiO ₂ , TiO ₂ , CrO ₂ and CeO ₂ , and SiN Any material of the nitride insulator is used.

  The anode electrode 17 is for injecting current into the active layer 111 through the cladding layer 112.

  The cathode electrode 19 is for injecting current into the active layer 111 from the lower part of the substrate 18 through the clad layer 113. The current is injected by applying a forward bias to the anode electrode 17 and the cathode electrode 19.

  The active layer 111 has a structure sandwiched between the clad layer 113 and the clad layer 112.

  As the material for the active layer 111 and the cladding layer, a mixed crystal semiconductor made of AlInGaN is used to obtain blue to ultraviolet excitation light. In general, a mixed crystal semiconductor mainly composed of AlGaInAsPNSb is used as an active layer / cladding layer of a semiconductor laser, and such a configuration may be used. Moreover, you may be comprised by II-VI group compound semiconductors, such as ZnMgSSeTe and ZnO.

  The active layer 111 is a region where light emission is caused by the injected current, and the emitted light is confined in the active layer 111 due to a difference in refractive index between the cladding layer 112 and the cladding layer 113.

  Further, the active layer 111 is formed with a front side cleaved surface 114 and a back side cleaved surface 115 provided to face each other in order to confine light amplified by stimulated emission, and the front side cleaved surface 114 and the back side cleaved surface 115. Plays the role of a mirror.

  However, unlike a mirror that completely reflects light, a part of the light amplified by stimulated emission is obtained by cleaving the front side cleaved surface 114 and the back side cleaved surface 115 of the active layer 111 (in this embodiment, the front side cleaved surface 114 for convenience. And the excitation light L0. Note that the active layer 111 may form a multilayer quantum well structure.

  Note that a reflective film (not shown) for laser oscillation is formed on the back side cleaved surface 115 opposite to the front side cleaved surface 114, and the difference in reflectance between the front side cleaved surface 114 and the back side cleaved surface 115 is different. By providing, for example, most of the excitation light L0 can be emitted from the light emitting point 103 from the front-side cleavage surface 114 which is a low reflectance end face.

  The clad layer 113 and the clad layer 112 are made of n-type and p-type GaAs, GaP, InP, AlAs, GaN, InN, InSb, GaSb, and AlN group III-V compound semiconductors, and ZnTe, ZeSe. , ZnS, ZnO, and other II-VI group compound semiconductors, and by applying a forward bias to the anode electrode 17 and the cathode electrode 19, current can be injected into the active layer 111. It has become.

  As for film formation with each semiconductor layer such as the clad layer 113, the clad layer 112, and the active layer 111, MOCVD (metal organic chemical vapor deposition) method, MBE (molecular beam epitaxy) method, CVD (chemical vapor deposition) method. The film can be formed using a general film forming method such as a laser ablation method or a sputtering method. The film formation of each metal layer can be configured using a general film forming method such as a vacuum deposition method, a plating method, a laser ablation method, or a sputtering method.

(Light emission principle of the light emitting unit 7)
Next, the light emission principle of the phosphor by the laser light oscillated from the semiconductor laser 3 will be described.

  First, the laser light oscillated from the semiconductor laser 3 is irradiated onto the phosphor included in the light emitting unit 7, whereby electrons existing in the phosphor are excited from a low energy state to a high energy state (excited state).

  Since this excited state is unstable, the energy state of the electrons in the phosphor is changed to the original low energy state after a certain time (the energy state of the ground level or the level between the excited level and the ground level). Transition to a stable level energy state).

  In this way, the phosphors emit light when electrons excited to the high energy state transition to the low energy state.

  White light can be composed of a mixture of three colors that satisfy the principle of equal color, or a mixture of two colors that satisfy the relationship of complementary colors. Based on this principle, the color of the laser light emitted from the semiconductor laser and the phosphor White light can be generated by combining the color of emitted light as described above.

(Another expression of the present invention)
The present invention can also be expressed as follows.

  That is, the laser illumination light source (illumination device) according to the present invention causes the phosphor light emitting portion to emit light by the excitation light emitted from the semiconductor laser that is the excitation light source, and radiates the light beam in a predetermined direction by the reflection optical system. A laser illumination light source that further has a small lens on the front surface of the phosphor light emitting part (opening side of the reflecting optical system), and a small cone line connecting the outer edge of the reflecting optical system opening and the phosphor light emitting part. The effective diameter of the lens.

(Supplement)
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  For example, in the present embodiment, the light emitting unit 7 and the emission adjusting lens 20 are separated from each other. However, the present invention is not limited thereto, and these members may be in contact with each other. Moreover, these members may be integrally formed. In this case, it is necessary to have a refractive index capable of irradiating the irradiation region S1 with the light emitted from the light emitting unit 7, but the emission adjustment lens 20 can be further reduced. Further, it is possible to suppress the emission of light in an unnecessary direction without providing a hole other than a laser beam incident part (for example, an optical fiber part) in the reflecting mirror 8.

  The present invention provides an illuminating device that can improve the utilization efficiency of emitted light, and can be applied to indoor illuminating devices such as headlamps and downlights for vehicles.

1 Headlamp (lighting device, vehicle headlamp)
2 Semiconductor laser array (excitation light source)
3 Semiconductor laser (excitation light source)
7 Light emitting part 7a Laser light irradiation surface (light receiving surface)
8 Reflector 10 Housing (housing)
20 Output adjustment lens (lens)
20A Output adjustment lens (lens)
30 hole S1 irradiation area S2 opening area

Claims (7)

An excitation light source that emits excitation light;
A light emitting unit that emits light in response to excitation light emitted from the excitation light source;
A reflecting mirror that reflects the light emitted from the light emitting unit;
A lens that bends the light emitted from the light emitting unit,
An irradiation area in which light emitted from the reflecting mirror is irradiated on a plane perpendicular to the optical axis of the reflecting mirror is within an area satisfying the light distribution standard of the device itself, and an opening area of the reflecting mirror The reflector is designed to be larger than
The lens receives the light from the light emitting part, thereby causing the light beam traveling in a solid angle formed by a straight line connecting the optical axis and an outer edge part of the irradiation area and an end part of the diameter of the lens. Forming ,
The light emitting unit has a light receiving surface that receives excitation light from the excitation light source,
The end of the diameter of the lens is on the generatrix passing through the outer edge of the light receiving surface and the outer edge of the reflector,
The illumination device characterized in that the lens is spaced apart from the light emitting portion and the opening of the reflecting mirror, and is disposed between the opening of the reflecting mirror and the light emitting portion . The lighting device according to claim 1, wherein the lens has a spherical shape. On the surface of the lens, the illumination device according to claim 1 or 2, characterized in that the anti-reflection film that prevents reflection of emitted light is provided. The lighting device according to any one of claims 1 to 3 , wherein the lens is made of an inorganic material. The illumination device according to any one of claims 1 to 4 , wherein a hole centered on the optical axis is formed in the reflecting mirror. An excitation light source that emits excitation light;
A light emitting unit that emits light in response to excitation light emitted from the excitation light source;
A reflecting mirror that reflects the light emitted from the light emitting unit;
A lens that bends the light emitted from the light emitting unit,
An irradiation area in which light emitted from the reflecting mirror is irradiated on a plane perpendicular to the optical axis of the reflecting mirror is within an area satisfying the light distribution standard of the device itself, and an opening area of the reflecting mirror The reflector is designed to be larger than
The lens receives the light from the light emitting part, thereby causing the light beam traveling in a solid angle formed by a straight line connecting the optical axis and an outer edge part of the irradiation area and an end part of the diameter of the lens. Forming,
The reflecting mirror is formed with a hole centered on the optical axis,
It said holes are in a plane perpendicular to the optical axis, and lighting devices you being a same size as the plane including the diameter of the lens. The lighting device according to any one of claims 1 to 6 ,
A vehicle headlamp comprising: a housing that houses the lighting device.

Images