JP6169383B2 - Light emitting module and light source device - Google Patents

Description

  A light source that combines a solid-state light source such as an LED and a phosphor layer has been widely used. However, in recent years, the brightness has been increased, and its application range such as general lighting and automobile headlamps has been expanded. It is believed that such light sources will continue to be used in a wider variety of applications by increasing the brightness.

  As a method for increasing the brightness of a light source, it has been proposed to use a phosphor in a reflective manner (Patent Document 1). In this method, the optical semiconductor and the phosphor layer are arranged spatially apart from each other, and the light emission is used in a reflection system. The light emission from the phosphor layer excited by the excitation light from the solid light source and the phosphor layer This is a method using both of the reflected light of the excitation light reflected by the light source. By adopting the reflection method, the reflected light of the excitation light can also be used as illumination light, so that high brightness can be achieved.

  Moreover, in the method of patent document 1, excitation light can be reflected in multiple times by using the fluorescent substance layer which has a some reflection layer. In the process, the optical path length of the excitation light can be increased, and the light conversion efficiency can be improved.

JP 2012-89687 A

  In a light emitting device that emits light by irradiating a phosphor with excitation light, there is a problem of eye safety that prevents excitation light from being directly irradiated to human eyes. In the technique described in Patent Document 1, by increasing the optical path length of the excitation light in the phosphor layer, the amount of excitation light emitted to the outside is reduced, so that eye safety can be achieved to some extent. However, in this technique, since the excitation light is reflected a plurality of times in the fluorescent member, the configuration of the light reflection surface is limited to a specific incident angle. For this reason, if the incident angle of the phosphor changes due to, for example, the optical axis of the excitation light source deviating or the position / angle of the substrate deviating, the excitation light will be emitted in an unexpected direction. In that case, the target eye safety cannot be improved.

  On the other hand, as a method for improving eye safety, it is conceivable to shield the optical path of reflected light with a non-reflective material or the like. However, when the change in the incident angle of the excitation light is also taken into consideration, the area of the nonreflective material to be shielded becomes large, so that the apparatus becomes large.

  An object of the present invention is to improve eye safety by controlling the optical path of reflected light while preventing an increase in the size of a reflection type light emitting module in which excitation light and a fluorescent member are combined.

  In order to solve the above problems, the present invention provides a light retroreflective structure on a light emitting body that emits light by excitation light or a reflecting surface provided between a light emitting body and a substrate. That is, the light emitting module of the present invention includes a substrate, a light emitter that is partially embedded in the substrate and emits light upon receiving excitation light, and a reflective surface provided on a contact surface between the substrate and the light emitter. The light emitting module is characterized in that either one of the reflective surface and the light emitter has a retroreflective structure.

According to the present invention, since the light emitter or the reflecting surface has a retroreflective structure, the direction of the reflected light is the same as the direction of the incident light regardless of the incident angle of the excitation light. Therefore, it is possible to prevent the reflected light of the excitation light from being radiated in an unexpected direction, and to improve eye safety.
Furthermore, by providing a certain relationship between the size of the light emitter and the irradiation diameter of the excitation light, it is possible to improve eye safety while maintaining the luminance while preventing the light emitting surface of the light emitter from being enlarged.

The figure which shows the basic structure of the light source device with which this invention is applied. (A), (b) is a sectional side view which shows the light emitting module of 1st embodiment, respectively. The figure explaining the retroreflection function in the light emitting module of 1st embodiment (A)-(d) is a figure which shows an example of the manufacturing method of the light emitting module of 1st embodiment. Side sectional view showing the light emitting module of the second embodiment The figure explaining the shape of the light-emitting body of the light emitting module of 2nd embodiment. The figure explaining the retroreflection function of the light-emitting body of the light emitting module of 2nd embodiment. Side sectional view of the light emitting module of the third embodiment Plan view of the light emitting module of the third embodiment Side sectional view showing a light emitting module of a fourth embodiment (A), (b) is side sectional drawing of the light emitting module of 5th embodiment, respectively. Schematic configuration diagram of the light source device of the sixth embodiment

Embodiments of the present invention will be described below.
The light emitting module of the present invention includes a substrate, a light emitter partially embedded in the substrate, and a reflective surface provided on a contact surface between the substrate and the light emitter, and the reflective surface or the light emitter has a retroreflective structure. It is to be prepared. The retroreflective property is a property of emitting light incident on the light emitter in the same direction as the incident direction, and the reflective surface having the retroreflectivity and the structure of the light emitter can take several forms.

  Before describing each embodiment of a light emitting module, first, the basic structure of a light source device to which a light emitting module of the present invention is applied will be described with reference to FIG.

  FIG. 1 is a diagram illustrating a schematic configuration of a light source device. The light source device 100 includes, as basic elements, a solid light source 2 that generates excitation light, a light emitting module 10, a solid light source 2, and a light emitting module 10. And an optical member 3 for light extraction disposed therebetween.

  The light emitting module 10 includes a substrate 11, a light emitting body 12 partially embedded in the substrate 11, a reflective layer 13, and a bonding layer 14 that bonds the light emitting body 12 and the substrate 11.

  As the solid-state light source 2, a light-emitting diode or a laser diode having a light emission wavelength in a range from ultraviolet light to blue light can be used. Although these light sources are not limited, for example, a laser diode that emits blue light of about 450 nm using a GaN-based material has high excitation light intensity, and the effects of the present invention are remarkably exhibited. Is preferred.

  The optical member 3 can be a dichroic mirror that transmits the excitation light from the solid-state light source 2 and reflects light other than the excitation light out of the light emitted from the light emitter 12.

  The solid light source 2 and the light emitting module 10 are arranged to face each other with a predetermined distance so that light emitted from the solid light source 2 is directed to the light emitting module 1, and the dichroic mirror 3 is arranged in the middle of the optical path. Between the dichroic mirror 3 and the light emitting surface of the light source device 100, other optical members or reflectors (not shown) may be disposed. In the light source device 100, the light extraction direction is determined by the traveling direction of light emitted from the solid light source 2 and the angle of the dichroic mirror 3.

Next, each element which comprises the light emitting module 10 common to each embodiment of this invention is demonstrated.
The light emitting body 12 constituting the light emitting module 10 absorbs excitation light emitted from the solid light source 2 and emits light having a wavelength different from that of the excitation light, and is obtained by dispersing phosphor powder in glass, a glass matrix. For example, a glass phosphor in which a luminescent center ion is added, a phosphor ceramic that does not include a binding member such as a resin, or the like can be used.

As the phosphor, one that absorbs light in the ultraviolet to blue light region and emits light having a longer wavelength than the excitation light can be used. For example, for red, CaAlSiN ₃ : Eu ²⁺ , (Ca, Sr) AlSiN ₃ : Eu ²⁺ , Ca ₂ Si ₅ N ₈ : Eu ²⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ²⁺ , KSiF ₆ : Mn ⁴⁺ , KTiF _6: Mn ⁴⁺ is Y ₃ Al ₅ O ₁₂ : Ce ³⁺ , (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ , Ca _x (Si, Al ) ₁₂ (O, N) ₁₆ : Eu ²⁺ , Lu ₃ Al ₅ O _12: Ce ³⁺ , Y ₃ (Ga, Al) ₅ O ₁₂ : Ce ³⁺ , Ca ₃ Sc ₂ Si ₃ O for green ₁₂ : Ce ³⁺ , CaSc ₂ O ₄ : Eu ²⁺ , (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ , Ba ₃ Si ₆ O ₁₂ N ₂ : Eu ²⁺ , (Si, Al) ₆ (O, N) ₈ : Eu ^{2+ and the} like can be used. These phosphors are powdered and mixed in one or more kinds and dispersed in glass containing components such as P ₂ O ₃ , SiO ₂ , B ₂ O ₃ , Al ₂ O _3. The light emitter 12 can be obtained.

  Moreover, the fluorescent substance ceramic which does not contain a resin component substantially is obtained by sintering the fluorescent substance mentioned above. As the phosphor ceramic, it is particularly desirable to use a phosphor ceramic having translucency. Translucent phosphor ceramics are phosphor ceramics that have become translucent because there are almost no pores or grain boundary impurities that cause light scattering in the sintered body. The conductivity is shown. For this reason, when used as a light emitter, the excitation light and fluorescence can be taken out from the light emitter without being lost by diffusion, and the heat generated in the light emitter can be efficiently diffused. Even a sintered body that does not show translucency is desirable to have as few pores and impurities as possible. As an index for evaluating the remaining amount of pores, the value of specific gravity of the phosphor ceramic can be used, and it is desirable that the value is 95% or more with respect to the theoretical value by which the value is calculated.

Glass phosphors with luminescent center ions added to the glass matrix include Ca-Si-Al-ON and Y-Si-Al-ON oxynitrides with Ce ³⁺ and Eu ²⁺ added as activators System glass phosphor.

  The phosphor 12 dispersed in the glass, the phosphor ceramic, or the glass phosphor is formed into a predetermined shape to form the light emitter 12. The shape of the light emitter 12 is a sphere, a specific triangular pyramid, or the like, and details thereof will be described later.

An antireflection layer can be provided on the portion of the light emitter 12 exposed from the substrate 11 or the portion that becomes the light incident surface. As the antireflection layer, known materials such as MgF ₂ , SiO ₂ , and multilayer films can be used. The antireflection layer can be formed by vapor deposition or a wet method, and the thickness is preferably about several tens of nm to 500 nm.

  As the substrate 11, a metal substrate, ceramics, or the like can be used, and a metal substrate having particularly high light reflection characteristics, heat transfer characteristics, and workability is preferable. As the metal, a simple substance such as Al, Cu, Ti, Si, Ag, Au, Ni, Mo, W, Fe, Pd, or an alloy can be used. The surface of the heat dissipation substrate may be subjected to an appropriate surface treatment as necessary, such as plating, sputtering film formation, or vapor deposition film formation. Further, a concave portion having a shape reversed from the shape of the light emitter 12 is formed on the surface of the substrate 11 on which the light emitter 12 is provided. The recess can be formed by a known cutting technique such as microlithography. The light emitter 12 is embedded in the recess through the reflective layer 13. Retroreflectivity is obtained by the shape of the reflective layer 13 and the light emitter 12 formed on the concave surface. A structure such as a heat radiating fin may be arranged on the side of the substrate 11 opposite to the surface on which the light emitter 12 is provided.

The reflection layer 13 is made of a metal reflection film such as Ag, Ag alloy, Pt, Au, Cu, Ti, or Si, and a dielectric multilayer film such as SiO ₂ , Al ₂ O ₃ , TiO ₂ , or ZnO. The reflective layer can be formed by a method such as sputtering, vacuum deposition, or plating. The surface of the reflective layer may be subjected to a surface treatment suitable for joining metal bumps as necessary, such as plating, sputtering film formation, and vapor deposition film formation. The reflective layer 13 can be formed directly on the surface of the light emitter 12, but may be formed on the substrate 11.

  The bonding layer 14 is formed between the reflective layer 13 and the substrate 11 when the reflective layer 13 is formed on the surface of the light emitter 12, and the reflective layer 13 when the reflective layer 13 is formed on the surface of the substrate 11. This is a layer that joins the light emitter 12. The bonding layer 14 is made of a high heat resistant material such as a silicone resin, a heat conductive adhesive, AuSn, solder, or glass. When the reflective layer 13 is directly formed on the light emitter 12, the bonding layer 14 may have light absorption, but the reflective layer 13 is not formed on the light emitter 12 and the reflective layer 13 is formed on the substrate 11. In this case, the bonding layer 14 is preferably translucent such as transparent silicone resin or glass.

  Next, each embodiment of the retroreflection structure of the light emitting module will be described.

<First embodiment>
The present embodiment is characterized in that a light emitter 12 made of a sphere is used to obtain a retroreflective structure. FIG. 2 shows a side view of the light emitting module 1. FIG. 3 is a diagram illustrating an optical path in the light emitter 12 of the present embodiment.

  As shown in FIG. 2A, the light emitter 12 of the present embodiment is formed of a sphere, and the substrate 11 is provided with a recess 11a that receives approximately half of the light emitter 12 (hemisphere portion). The light-emitting body 12 has a reflective layer 13 formed in a hemispherical portion that is a portion embedded in the recess 11 a and is fixed to the substrate 11 by a bonding layer 14. Alternatively, as shown in FIG. 2B, a structure in which the reflective layer 13 is formed in the concave portion 11a of the substrate 11 and the light emitter 12 is fixed to the reflective layer 13 formed in the concave portion 11a by the bonding layer 14 may be used. Here, in the case where the substrate 11 itself is a highly reflective material, the surface of the recess 11a becomes a reflective surface, so that the reflective layer 13 can be omitted.

  It is preferable that the size of the light emitting body 12 formed of such a sphere is such that the excitation light from the light source can be treated as approximately parallel light in relation to the distance from the light source 2. Specifically, the size is preferably on the same order as the irradiation diameter of the excitation light. When the diameter of the sphere is R and the diameter with respect to the irradiation surface of the excitation light is φ, 1.0φ <R <10φ. It is desirable to be in the range. When R <1.0φ, there is a possibility that a part of the excitation light cannot enter the phosphor. In the case of R> 10, the luminance decreases because the light emitting surface of the phosphor becomes large. As an example, R = 500 μm and φ = 100 μm can be mentioned.

  In addition, the illuminant can be considered as a sphere lens, and it is desirable that the focal length be present on or near the surface of the spherical illuminant in order to obtain retroreflectivity. When the focal length is located on the spherical surface, the focal point coincides with the reflecting surface formed on the spherical surface. Thereby, as indicated by arrows in FIG. 3, all the light incident on the spherical phosphor is collected at the focal point 16 existing on the optical axis. The light collected in this way is reflected by the reflecting surface present on the focal point, but the path of the reflected light is the path of the incident light folded back with respect to the optical axis due to the symmetry of the spherical phosphor. Is equal to Therefore, the reflected light returns in the same direction as the incident light, and a retroreflection function is obtained.

In order to make the focal point the surface of the sphere, it is desirable that the luminous body 12 has a refractive index in the range of 1.5 to 2.0. Here, when the refractive index n and the focal length f of the spherical phosphor (spherical lens) are used, the relationship can be obtained by the following equation (1).
1 / f = (n-1 ) (1 / R 1 - 1 / R 2) + d (n-1) 2 / (nR 1 R 2) (1)
In the above formula, d: lens thickness, R1: lens radius on the incident surface side, R2: lens radius on the opposite side In the above formula, R1 = R2 = r (sphere radius), and when n = 2, f = R. That is, the focal point exists on the spherical surface. That is, it is most desirable that the refractive index of the spherical phosphor capable of obtaining the retroreflection function is n = 2 where the focal point exists on the spherical surface. However, even in the case of 1.5 <n <2.0, the focal point exists in the vicinity of the spherical phosphor, so that a retroreflection function can be obtained by forming a reflective layer on the spherical phosphor.

  The retroreflection function can also be obtained by forming a reflective surface on the reflective surface of the heat dissipation substrate without forming a reflective layer on the spherical phosphor. For example, when the radius of the sphere r = 50 μm and the refractive index n = 1.8, the focal length f = 56.3 μm is obtained. In this case, the distance L between the surface of the spherical light emitter and the focal point is L = f−r = 6.3 μm. However, when the refractive index is less than 1.5, the distance between the spherical light emitter and the focal point becomes large. Therefore, if the reflective layer is provided at such a distance, the heat dissipation of the phosphor layer is deteriorated, which is not desirable. For example, when the radius of the sphere r = 50 μm and the refractive index n = 1.4, since f = 87.5 μm, the distance between the light emitter and the focal point is L = f−r = 37.5 μm. Since the distance to the reflective layer exceeds 30 μm, the heat dissipation of the phosphor layer cannot be ensured.

  Next, the manufacturing method of the light emitting module of this embodiment is demonstrated. FIG. 4 shows an example of the manufacturing process. First, a spherical light emitter 12 is produced using a material such as a glass phosphor or phosphor ceramic (a). Next, a temporary mold (for example, made of aluminum) 15 having a hemispherical recess having the same radius as that of the spherical light emitter is prepared, and the light emitter 12 prepared in (a) above is placed on the recess, and a film forming apparatus such as a sputtering apparatus is provided. The reflective layer 13 is formed on the temporary mold 15 (b). Separately, a substrate 11 having a hemispherical recess having the same radius as that of the light emitter 12 is prepared, and an adhesive serving as a bonding layer 14 is applied in the recess. The substrate 11 after application of the adhesive is placed on the light emitter 12 on which the reflective layer 13 is formed, pressed, and the adhesive is heated and cured (c). Finally, the temporary mold 15 is removed to obtain the light emitting module 1 of the present embodiment (d).

  The manufacturing method described above is an example, and the manufacturing method of the light emitting module of the present embodiment is not limited to the illustrated method. For example, the reflective layer 13 is formed in the concave portion in a state where the portion other than the concave portion of the substrate 11 on which the hemispherical concave portion is formed is masked, and then an adhesive is applied to the reflective layer 13 so that the spherical light emitter 12 is formed. It may be placed and the adhesive cured.

  According to the light emitting module of the present embodiment, retroreflectivity can be obtained by using a sphere having an appropriate refractive index as the light emitter 12, and the optical axis of the excitation light from the solid light source 2 is shifted. In addition, it is possible to prevent an accident that the excitation light is irradiated in an unexpected direction, and to improve eye safety.

<Second embodiment>
This embodiment is characterized by using a triangular pyramid light emitter 12. FIG. 5 is a side view of the light emitting module 1, FIG. 6 is a diagram illustrating the shape of a triangular pyramid, and FIG. 7 is a diagram illustrating the retroreflective function of the light emitter 121 as viewed from above.

  In the light emitting module 10 of the present embodiment, as shown in FIG. 5, a concave portion having the same shape as the triangular pyramid of the light emitter 12 is formed on the substrate 11, and the light emitter 12 has a bottom surface of the triangular pyramid as a light emitting surface. Further, it is embedded in the recess of the substrate 11. A reflective layer 13 is formed on the side surface (three side surfaces of the triangular pyramid) of the light emitter embedded in the concave portion of the substrate 11, and a bonding layer 14 is formed between the concave portion of the substrate 11 and the reflective layer 13.

  As shown in FIG. 6, the triangular pyramid of the light emitter 12 is a triangle formed by connecting three vertices B, C, and D adjacent to one vertex A of the cube, and has a shape obtained by cutting the cube. That is, the base is a regular triangle, and the three side surfaces are triangular pyramids made of right-angled isosceles triangles. In such a triangular pyramid, each side surface has an angle of 45 degrees with respect to the bottom surface, and thus has a retroreflectivity with respect to light incident perpendicular to the bottom surface when the bottom surface is a light incident surface. This will be described with reference to FIG. For example, light that hits one side surface (a side surface defined by ABC) perpendicularly from the top of the paper is reflected in a surface (a triangular surface indicated by a dotted line) perpendicular to the light and reflected on the other side surface (for example, ABC). Side). The light hitting this side face is reflected at the same reflection angle as the incident angle in the same orthogonal plane, and hits a reflection face (side face defined by ACD) adjacent thereto. At this time, the incident angle to the ACD plane in the orthogonal plane is 90 degrees, and the light is reflected again in the vertical direction (outgoing plane direction) by this plane and reflected in the direction opposite to the direction in which the light is incident. That is, retroreflectivity is obtained.

  The size of the triangular pyramid can be considered in the same way as when the light emitter 12 is a sphere. When the length of one side of the bottom surface is L and the diameter of the excitation light irradiation surface is φ, 1.0φ < L <10φ is desirable.

  The light emitting module of this embodiment can also be manufactured by the same manufacturing method as in the first embodiment.

  The effect of the light emitting module of this embodiment is the same as that of the first embodiment. However, the light emitting module of this embodiment has a flat light incident surface of the light emitter 12 and is orthogonal to the light incident direction. The refractive index is not limited as in the case of a sphere, and the degree of freedom of the material is large.

  In the present embodiment, a case has been described in which a triangular pyramid having a shape obtained by cutting a cube with a triangle connecting the three vertices of the cube shown in FIG. 6 is used as a light emitter, but this corresponds to the triangular pyramid without cutting the cube. The same retroreflectivity can be obtained even when only the portion is buried in the concave portion of the substrate 11 through the reflective layer 13 and the other portion is exposed on the substrate 11. However, it is necessary to provide an antireflection layer in order to prevent reflection of excitation light on each surface of the shape exposed from the substrate 11.

<Third embodiment>
The light emitting module of the present embodiment is obtained by arranging a plurality of light emitters of the second embodiment. FIG. 8 is a sectional view of the light emitting module, and FIG. 9 is a plan view. The sectional view of FIG. 8 is an AA section of FIG.

  As shown in FIGS. 8 and 9, the light emitting module of this embodiment has a structure in which a light emitting body 12 made of a plurality of triangular pyramids is arranged on a substrate 11 without a gap. As in the third embodiment, each triangular pyramid is a triangular pyramid having a regular triangle on the bottom and a right isosceles triangle on the side. Although FIG. 9 shows a case where six triangular pyramids are arranged in a hexagonal shape, the number of triangular pyramids to be arranged and the arrangement method are not limited to those illustrated. For example, a triangular arrangement or a one-dimensional arrangement can be used.

  In FIG. 9, three triangular pyramids having the same direction, which are indicated by diagonal lines, are shapes in which corner cubes obtained by stacking cubes shown in FIG. Therefore, the light emitter 12 of the present embodiment can also be manufactured by combining two triangular pyramids cut out from a corner cube.

  The light emitting module of this embodiment can also obtain retroreflectivity similarly to the first and second embodiments, and the same effects as those of these embodiments can be obtained. Furthermore, since the area of the light emitting module of the present embodiment can be increased without increasing the thickness of the light emitter 12, it is suitable for a light source device that requires a large area.

<Fourth embodiment>
The first to third embodiments described above are embodiments in which the light-emitting body 12 is provided with a retroreflective function, but this embodiment is characterized in that the reflective layer formed on the substrate is provided with a retroreflective function. It is. As the light emitter, a conventionally used rectangular parallelepiped phosphor plate can be used. FIG. 10 shows a side view of the light emitting module of this embodiment.

  In the present embodiment, a large number of concave portions having the same shape as the triangular pyramids of the second and third embodiments are formed in the substrate 11 without gaps, and the concave portions serve as reflecting surfaces. The method of forming the reflective layer 13 is the same as that of each of the embodiments described above, but the inside thereof is filled with a bonding agent to form a bonding layer 14, and a rectangular parallelepiped light emitter (phosphor plate) 12 is disposed thereon. The bonding layer 14 has a function of releasing the heat generated from the light emitter (phosphor plate) 12 to the outside and a function of transmitting the light that has passed through the light emitter (phosphor plate) 12 to the reflecting surface on the heat dissipation substrate without absorbing it. is necessary. Therefore, the bonding agent preferably has translucency. As the light-transmitting bonding agent, for example, a transparent silicone resin or transparent glass can be used.

  Since the heat dissipation decreases as the thickness of the bonding layer 14 increases, the height h of each triangular pyramid is preferably 30 μm or less. The triangular pyramid may be provided on the entire surface of the substrate 11, for example, but by providing a triangular pyramid concavity limited to the excitation light irradiation portion, the amount of the bonding agent that hinders heat dissipation is minimized. This is advantageous.

  The size of the rectangular parallelepiped illuminant 12 can be considered in the same manner as in the case of the spherical illuminant. When the length of the diagonal line of the upper surface of the cuboid viewed from above is L, the diameter φ of the irradiation surface of the excitation light is On the other hand, the range of 1.0φ <L <10φ is desirable.

  The light emitting module of this embodiment can also obtain retroreflectivity similarly to the first to third embodiments, and the same effects as those of these embodiments can be obtained. In addition, the present embodiment is effective in that the eye safety can be obtained without losing the retroreflective function even if the light emitter is dropped.

<Fifth embodiment>
In the above embodiment, the case where the light emitter includes a phosphor has been described. However, the light emitting module of the present embodiment uses a transparent body instead of the light emitter in the first to fourth embodiments, and the bonding agent is fluorescent. The point is that the body is used. That is, in the present embodiment, the transparent body and the bonding layer constitute a light emitter. The light emitting module of this embodiment is shown in FIG. 11A shows a case where the transparent body 17 is a sphere, and FIG. 11B shows a case where the transparent body 17 is a triangular pyramid.

  As shown in FIG. 11, also in the light emitting module of the present embodiment, the recesses are formed in the substrate 11 as in the first to fourth embodiments. A reflective layer 13 is formed in the concave portion of the substrate 11. The reflective layer 13 is made of a metal reflective film or a dielectric multilayer film, and can be formed by sputtering or the like.

  The bonding layer 14 is a layer in which phosphor powder is uniformly mixed with a binder, and the phosphor described in the first embodiment can be used as the phosphor. As the binder, a thermosetting resin such as glass or silicone resin can be used. Although the density | concentration of the fluorescent substance powder in the joining layer 14 is not limited, It is preferable that it is 10 to 90 weight% of the whole layer.

  The transparent body 17 is made of a material that transmits excitation light from a solid light source and light emitted from a phosphor contained in the bonding layer. Specifically, a resin such as glass or acrylic resin can be used. In the case where the transparent body 17 is a sphere as shown in FIG. 11A, the refractive index n is preferably 1.5 to 2.0 in order to obtain retroreflectivity. The shape of the transparent body is the same as the shape of the light emitter in the first embodiment or the second embodiment.

In the light emitting module of this embodiment, when the binder (bonding agent) constituting the bonding layer is a thermosetting resin, the phosphor-containing bonding agent described above is applied to the substrate 11 having the reflective layer 13 formed in the concave portion with a predetermined thickness. After the application, the transparent body 17 is placed and heated to a predetermined temperature (for example, at 150 ° C. for 4 hours) to cure the resin.

Also in the light emitting module of this embodiment, the eye safety can be improved by the retroreflection function as in the first to fourth embodiments described above.
Although FIG. 11 shows a case where the transparent body is a sphere or a triangular pyramid, the transparent body may have a large number of triangular pyramids.

<Sixth embodiment>
Next, an embodiment of a light source device using the light emitting module of the present invention will be described.
In FIG. 12, the outline | summary of the light source device 200 of this embodiment is shown. The light source device 200 includes a blue LD 210, a light emitting module 10, a red LED 220, a DMD (Digital Micromirror Device) 230, a half mirror 240, and a plurality of dichroic mirrors 251 to 253. It can be used as a device. The dichroic mirrors 251 to 253 have different designs for the transmitted wavelength and the reflected wavelength.

  The blue LD 210 and the light emitting module 10 are arranged to face each other, and the light emitted from them is extracted by the half mirror 240 and the dichroic mirror 251, mixed with the light generated from the red LED 220, and sent to the DMD 230. That is, a half mirror 240 and a dichroic mirror 251 are sequentially arranged between the blue LD 210 and the light emitting module 10, and two dichroic mirrors 252 and 253 are arranged between the red LED 220 and the DMD 230. The dichroic mirror 252 is disposed at a position where the light from the dichroic mirror 251 is received, and the dichroic mirror 253 is disposed at a position where the light from the half mirror 240 is received.

  In such a configuration, blue light (or ultraviolet light) emitted from the blue LD 210 passes through the half mirror 240 and the dichroic mirror 251 and enters the light emitting module 10. Further, a part of the excitation light is directed to the dichroic mirror 253 when passing through the half mirror 240. In the light emitting module 10, fluorescence is emitted from the phosphor by the excitation light. This excitation light is directed toward the blue LD 210 as a light source by the retroreflection function, but the fluorescence is reflected by the dichroic mirror 251 in the direction of the dichroic mirror 252 and further reflected by the dichroic mirror 252 and directed to the DMD 230. At this time, the light from the light emitting module 10 is mixed with the light generated from the red LED 220, passes through the dichroic mirror 253, and is sent to the DMD 230. On the other hand, the dichroic mirror 253 further reflects the excitation light reflected by the half mirror 240 and directs it to the DMD 230. As a result, light enters the DMD 230 in a state where the light from the blue LD 210, the light from the light emitting module 10, and the light from the red LED 220 are mixed. As a result, light with very high luminance can be obtained.

  The application example of the light emitting module of the present invention has been described above. However, the light emitting module of the present invention is not limited to the above-described embodiment as long as it is a light source device having a basic structure as shown in FIG. It can be applied to a light source device.

  According to the present invention, it is possible to improve eye safety in a light source device using an LD light source.

DESCRIPTION OF SYMBOLS 2 ... Solid light source, 3 ... Optical member (dichroic mirror), 10 ... Light emitting module, 11 ... Substrate, 12 ... Luminescent body, 13 ... Reflective layer, 14 ... Joining Layer, 100, 200 ... light source device, 210 ... blue LD.

Claims (12)

  A light emitting module comprising: a substrate; a light emitter that is partially embedded in the substrate and that emits light upon receiving excitation light; and a reflective surface provided on a contact surface between the substrate and the light emitter. At least one of a reflective surface and the said light-emitting body was provided with the retroreflection structure, The light emitting module characterized by the above-mentioned. The light emitting module according to claim 1,
A concave surface having a triangular pyramid shape in which the bottom surface is an equilateral triangle and three side surfaces are right-angled isosceles triangles is formed on the surface of the substrate in which the light emitter is embedded, and the reflective surface covers the concave portion. A light emitting module formed on the substrate. The light emitting module according to claim 2,
The light-emitting module, wherein the reflective surface includes a plurality of triangular pyramid-shaped concave portions arranged without gaps. The light emitting module according to claim 2 or 3,
The light-emitting body has a portion embedded in the substrate having a shape in which the concave and convex portions are reversed, and is fixed to the concave portion by a light-transmitting adhesive material that transmits light emitted from the light-emitting body. A light emitting module characterized by. The light emitting module according to claim 4,
The light emitter has a triangular pyramid shape having a regular triangle on a bottom surface and three right side triangles, the three side surfaces are embedded in the substrate, and a reflecting surface on the three side surfaces. The light emitting module. The light emitting module according to claim 5,
The light emitting module according to claim 1, wherein the length of one side of the bottom surface of the light emitter is more than 1φ and less than 10φ when the diameter with respect to the surface irradiated with the excitation light is φ. The light emitting module according to claim 1,
A light emitting module , wherein a hemispherical recess is formed on a surface of the substrate in which the light emitter is embedded , and the reflection surface is formed on the substrate so as to cover the recess. . The light emitting module according to claim 7 ,
The light emitting module according to claim 1, wherein the light emitter is a sphere and has a reflective surface on a surface embedded in the substrate. The light emitting module according to claim 8,
The light emitting module according to claim 1, wherein the diameter of the sphere is greater than 1φ and less than 10φ when the diameter with respect to the excitation light irradiation surface is φ. The light emitting module according to claim 5 or 8 ,
The light-emitting module includes a substance that absorbs the excitation light and emits light having a different wavelength. The light emitting module according to claim 5 or 8 ,
The light-emitting module includes a main body made of a light-transmitting material that transmits the excitation light, and a light-emitting layer formed between the main body and the reflecting surface. A light source device comprising: a solid-state light source that emits laser light; a light-emitting module that includes a light-emitting body that receives and emits laser light; and a dichroic mirror disposed between the solid-state light source and the light-emitting module, light source apparatus comprising the light emitting module according to any one of claims 1 to 11 as a light emitting module.

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