JP2020004927A - Fluorescent light source device - Google Patents

Abstract

To provide a fluorescent light source device increased in extraction efficiency of fluorescent light.SOLUTION: A fluorescent light source device comprises: a wavelength conversion element 10 which has a first surface, a second surface arranged at a position opposite to a first direction so as to be separated from the first surface by a distance shorter than a side of the first surface or a diameter of a circumscription circle, and a third surface that communicates the first and second surfaces and is in non-parallel to the first and second surfaces, and generates fluorescent light of a second wavelength when entering light of a first wavelength; an excitation light source 20 which emits excitation light L20 of the first wavelength, which is arranged at a position separated in a second direction orthogonal to the third surface to the third surface of the wavelength conversion element; and an optical element 30 that is arranged between the excitation light source and the third surface of the wavelength conversion element, and irradiates the excitation light to a first irradiation region on the third surface of the wavelength conversion element. The wavelength conversion element converts the excitation light into the fluorescent light to eject it from the first surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fluorescent light source device including an excitation light source and a phosphor.

Conventionally, there is known a technique in which excitation light emitted from an LED (light emitting diode) is incident on a surface of a plate-shaped or rod-shaped phosphor, and fluorescence is extracted from another surface that is not opposed to the incident surface. (For example, see Patent Document 1 below).

JP-T-2018-503211

  In the fluorescent light source device disclosed in Patent Document 1, the distance between the excitation light and the phosphor is short. For this reason, it is difficult to efficiently exhaust the heat generated in the phosphor, and a phenomenon called temperature quenching occurs, and there is a problem that the fluorescence cannot be efficiently extracted.

  The present invention has been made in view of the above circumstances, and has as its object to provide a fluorescent light source device with improved fluorescence extraction efficiency.

The fluorescent light source device according to the present invention, the first surface, the side of the first surface with respect to the first surface, the diameter, or disposed at a position facing the first direction separated by a distance shorter than the diameter of the circumscribed circle. A second surface, which communicates the first surface and the second surface, has a third surface non-parallel to the first surface and the second surface, the light of the first wavelength is incident Then, a wavelength conversion element that generates fluorescence of a second wavelength different from the first wavelength,
For the third surface of the wavelength conversion element, disposed at a position separated in a second direction perpendicular to the third surface, an excitation light source that emits the excitation light of the first wavelength,
An optical element disposed between the excitation light source and the third surface of the wavelength conversion element, and irradiating the excitation light to a first irradiation area on the third surface of the wavelength conversion element,
The wavelength conversion element converts the excitation light into the fluorescence and emits the fluorescence from the first surface.

  According to the above configuration, the excitation light source and the wavelength conversion element are arranged apart from each other. As a result, the heat dissipation of the wavelength conversion element is improved as compared with the conventional structure. Further, the fluorescent light source device includes an optical element that irradiates a predetermined area (first irradiation area) on the third surface of the wavelength conversion element with the excitation light emitted from the excitation light source. As a result, even if the excitation light source is separated from the wavelength conversion element, the excitation light can be efficiently incident on the wavelength conversion element.

  The wavelength conversion element included in the fluorescent light source device includes two facing surfaces and a third surface connecting the two surfaces, and the two facing surfaces (the first surface and the second surface) are sides of the first surface. , A diameter or a diameter shorter than the diameter of a circumscribed circle. The wavelength conversion element receives the excitation light from the third surface and emits the fluorescent light from the first surface. As a result, since it is not necessary to separately provide an optical system for separating the excitation light incident on the wavelength conversion element and the fluorescence emitted from the wavelength conversion element, the device configuration can be simplified and downsized.

  The fluorescent light source device may include a cooling plate including a mounting surface on which the wavelength conversion element and the excitation light source are mounted. More specifically, the wavelength conversion element may be mounted such that the second surface is in contact with the mounting surface of the cooling plate directly or via another layer.

  According to the above configuration, since both the wavelength conversion element and the excitation light source can be cooled via the same cooling plate, the size of the entire apparatus can be reduced. Further, as described above, since the wavelength conversion element and the excitation light source are arranged apart from each other, high cooling performance is realized even when cooling is performed via the same cooling plate.

  The optical element may be fixedly arranged with respect to the cooling plate. According to such a configuration, optical alignment of both the optical element and the excitation light source and the optical element and the wavelength conversion element can be easily performed.

The third surface of the wavelength conversion element, a plurality of planes, curved surfaces, or a group thereof,
A plurality of the excitation light sources that make the excitation light incident on each of the plurality of first irradiation regions on the third surface may be provided.

  According to the above configuration, the excitation light emitted from the plurality of excitation light sources is incident on the wavelength conversion element in a state where the cooling performance is enhanced, so that high-output fluorescence can be generated in the wavelength conversion element.

  The total area of the first surface and the second surface may be larger than the total area of the third surface.

  According to the above configuration, since the amount of fluorescence emitted from the third surface side on which the excitation light is incident is suppressed, the efficiency of the fluorescence extracted from the first surface side constituting the fluorescence extraction surface is increased.

  The optical element may include a condensing optical system that condenses the excitation light on the first irradiation area. More specifically, a collimating lens that converts the excitation light into substantially parallel light and a condenser lens that collects the excitation light emitted from the collimating lens may be included.

  The optical element may include an optical waveguide that guides the excitation light to the first irradiation area. As the optical waveguide, for example, an optical fiber can be used. In this case, a condenser lens for condensing the excitation light on the incident surface of the optical waveguide may be further provided.

The excitation light source includes a semiconductor laser device in which a plurality of semiconductor layers are stacked,
The lamination direction of the semiconductor layers may be substantially parallel to the first direction.

  When the semiconductor laser device is a so-called “edge-emitting type” device, laser light is emitted from a surface configured by a stacking direction of the semiconductor layers and a direction orthogonal to the stacking direction. The light emitting region (also referred to as an “emitter”) has a shape that is longer in a direction perpendicular to the direction of lamination of the semiconductor layers due to the structural characteristics of the semiconductor laser device. By arranging the excitation light source such that the short direction of the emitter is in a direction substantially parallel to the first direction, the excitation light with respect to the third surface of the wavelength conversion element with leakage light as small as possible. Incident.

  Note that, in this specification, “the direction A and another direction B are“ substantially parallel ”” means that the absolute value of the angle between the direction A and the direction B is less than 3 °.

  The fluorescent light source device may include a first reflective film that is disposed in contact with the outside of the second surface of the wavelength conversion element and reflects light of the second wavelength.

  According to this configuration, the fluorescence generated in the wavelength conversion element and traveling to the second surface side can be reflected by the first reflection film and guided to the first surface side, and thus is extracted from the first surface side. The efficiency of extracting fluorescence is improved.

  In addition, the first reflection film may have a function of reflecting the light of the first wavelength. This allows the excitation light to be reflected by the first reflection film and returned to the inside of the wavelength conversion element, so that the fluorescence generation efficiency is improved.

  The fluorescent light source device may include a second reflection film that transmits the light of the first wavelength and reflects the light of the second wavelength on the third surface of the wavelength conversion element.

  According to the above configuration, since the fluorescence generated in the wavelength conversion element and advanced to the third surface side can be returned to the wavelength conversion element again, the extraction efficiency of the fluorescence extracted from the first surface side is improved. .

  The fluorescent light source device may include an anti-reflection layer for preventing reflection of the second wavelength light on the first surface of the wavelength conversion element.

  According to the above configuration, the fluorescence generated in the wavelength conversion element and traveling to the first surface side is extracted from the first surface side because the amount of light reflected on the first surface and returned to the wavelength conversion element decreases. The efficiency of extracting fluorescence is improved.

The fluorescent light source device is disposed at a position separated from the third surface of the wavelength conversion element in the second direction, and emits light having a wavelength different from both the first wavelength and the second wavelength. With a second light source,
The light emitted from the second light source may be applied to a second irradiation area different from the first irradiation area on the third surface of the wavelength conversion element.

  According to the above configuration, the fluorescence generated by the wavelength conversion element and the light having a wavelength different from the fluorescence are extracted from the first surface of the wavelength conversion element. By utilizing such light for lighting purposes such as projectors, the color rendering properties can be enhanced.

  ADVANTAGE OF THE INVENTION According to this invention, the fluorescence light source device with a high fluorescence extraction efficiency is implement | achieved with a small apparatus structure.

It is a top view showing typically composition of one embodiment of a fluorescent light source device of the present invention. FIG. 2 is a perspective view schematically illustrating a structure of a wavelength conversion element included in the fluorescent light source device illustrated in FIG. 1. FIG. 2 is a plan view schematically showing a wavelength conversion element included in the fluorescent light source device shown in FIG. 1. FIG. 2 is a cross-sectional view schematically illustrating a part of the fluorescent light source device illustrated in FIG. 1. It is a perspective view which shows an excitation light source typically. FIG. 5 is a partially enlarged view of FIG. 4. FIG. 2 is another cross-sectional view schematically illustrating a part of the fluorescent light source device illustrated in FIG. 1. It is a partially expanded view of another embodiment of FIG. It is another top view which shows typically the structure of one Embodiment of the fluorescent light source device of this invention. It is another top view which shows typically the structure of another embodiment of the fluorescent light source device of this invention. FIG. 11 is a cross-sectional view schematically illustrating a part of the fluorescent light source device illustrated in FIG. 10. It is sectional drawing which shows typically the wavelength conversion element with which the fluorescence light source device which concerns on another embodiment is provided. It is a top view which shows typically the structure of another embodiment of the fluorescent light source device of this invention. It is a top view which shows typically the structure of another embodiment of the fluorescent light source device of this invention.

  An embodiment of a fluorescent light source device according to the present invention will be described with reference to the drawings. Note that the following drawings are schematically shown, and the dimensional ratios in the drawings do not always match the actual dimensional ratios, and the dimensional ratios do not always match between the drawings.

  FIG. 1 is a plan view schematically illustrating a configuration of an embodiment of a fluorescent light source device. As shown in FIG. 1, the fluorescent light source device 1 includes a wavelength conversion element 10, an excitation light source 20, and an optical element 30. In this specification, the coordinate system illustrated in FIG. 1 is appropriately referred to.

  In the present specification, when it is not necessary to distinguish between positive and negative when describing a certain direction, it is simply described as “X direction”, “Y direction”, or “Z direction”. Further, when it is necessary to distinguish between positive and negative, it is appropriately described as “+ X direction”, “−X direction”, or the like. FIG. 1 schematically illustrates a configuration when the fluorescent light source device 1 is viewed from the Z direction.

  As shown in FIG. 1, in the present embodiment, the fluorescent light source device 1 includes a wavelength conversion element 10 having a substantially circular shape when viewed from the Z direction. The fluorescent light source device 1 includes a plurality of light source groups each including an excitation light source 20 and an optical element 30 for irradiating the wavelength conversion element 10 with excitation light L20 from a plurality of directions. In the example illustrated in FIG. 1, the fluorescent light source device 1 includes four sets of light source groups including an excitation light source 20 and an optical element 30, and the excitation light L20 emitted from each light source group is Irradiated from direction.

  FIG. 2 is a perspective view schematically showing the wavelength conversion element 10. In the present embodiment, the wavelength conversion element 10 has a cylindrical shape. That is, as shown in FIG. 2, the wavelength conversion element 10 has two opposing surfaces (11, 12) and a side surface 13 orthogonal to these two surfaces. As in the present embodiment, when the wavelength conversion element 10 has a cylindrical shape, the side surface 13 is formed of a curved surface. The surface 11 corresponds to the “first surface”, the surface 12 corresponds to the “second surface”, and the side surface 13 corresponds to the “third surface”. The Z direction in which the surfaces 11 and 12 face each other corresponds to the “first direction”, and the direction orthogonal to the side surface 13 corresponds to the “second direction”. That is, the second direction changes according to the position of the reference side surface 13, but is orthogonal to the first direction.

  The side surface 13 may have an inclination with respect to the two opposing surfaces (11, 12). In this case, the wavelength conversion element 10 has an oblique column shape. In this case, the second direction is orthogonal to the side surface 13 but has an angle with respect to the first direction according to the inclination.

  In the present embodiment, the wavelength conversion element 10 has a flat cylindrical shape. That is, the wavelength conversion element 10 has a shape in which the diameter r1 of the two facing surfaces (11, 12) is larger than the separation distance h1 of the two surfaces (11, 12). In the present specification, “diameter” means a diameter.

When the excitation light L20 emitted from the excitation light source 20 is incident, the wavelength conversion element 10 includes a fluorescent material that generates fluorescent light L10 having a different wavelength from the excitation light L20. Examples of such a material include YAG (Y ₃ Al ₅ O ₁₂ : Ce ³⁺ ), β-sialon (SrSiAlON: Eu ²⁺ ), and the like. However, in the present invention, the fluorescent material included in the wavelength conversion element 10 is arbitrary as long as the material generates the fluorescence L10 having a different wavelength from the excitation light L20 when the excitation light L20 is incident.

  In the present embodiment, the excitation light source 20 is configured by a laser diode element (hereinafter, sometimes referred to as an “LD element”). As a more specific example, the excitation light source 20 is an LD element that includes an active layer made of a nitride semiconductor such as GaN, InGaN, or AlInGaN and has a peak wavelength of 400 nm or more and 500 nm or less. However, in the present invention, the wavelength of the excitation light L20 emitted from the excitation light source 20 is not limited.

  In the present embodiment, the optical element 30 is disposed between the excitation light source 20 and the wavelength conversion element 10 and converts the excitation light L20 emitted from the excitation light source 20 into a predetermined light on the side surface 13 of the wavelength conversion element 10. This is a configuration that leads to an area. FIG. 3 is a schematic plan view when the wavelength conversion element 10 is viewed from a direction orthogonal to the Z direction (here, the Y direction). As shown in FIG. 3, the excitation light L20 is applied to a region 51 on the side surface 13 of the wavelength conversion element 10. When the wavelength conversion element 10 is irradiated with the excitation light L20 from four directions as in the example illustrated in FIG. 1, the excitation light L20 is applied to the four different regions 51 on the side surface 13. L20 is irradiated. The region 51 corresponds to a “first irradiation region”.

  When the excitation light L20 enters the wavelength conversion element 10 from the side surface 13 of the wavelength conversion element 10, it is converted into fluorescence L10 while traveling and diffusing inside the wavelength conversion element 10. The fluorescence L10 generated in the wavelength conversion element 10 is extracted from the surface 11 of the wavelength conversion element 10 to the outside (see FIG. 3). That is, in the present embodiment, the surface 11 of the wavelength conversion element 10 constitutes the extraction surface of the fluorescent light L10.

  FIG. 4 is a cross-sectional view schematically showing a part of the fluorescent light source device 1 extracted. FIG. 4 illustrates a state in which the wavelength conversion element 10 is irradiated with the excitation light L20 from both the + X direction and the −X direction, and the fluorescence L10 is emitted from the surface 11 of the wavelength conversion element 10.

  As shown in FIG. 4, the excitation light source 20 and the wavelength conversion element 10 are separated from each other in a direction orthogonal to the side surface 13 (X direction in FIG. 4). The optical element 30 is disposed between the optical element 10 and the optical element 10. Further, the wavelength conversion element 10, the excitation light source 20, and the optical element 30 are mounted on the surface of the common cooling plate 3. The cooling plate 3 is made of a material having relatively high thermal conductivity, such as Cu, Cu alloy, Al, and AlN.

  In the present embodiment, the optical element 30 includes two lenses (32, 33) and a pedestal portion 31 on which these lenses are fixedly arranged. As an example, the lens 32 can be configured by a collimating lens, and the lens 33 can be configured by a condenser lens.

  As shown in FIG. 4, the cooling plate 3 may have a concave portion 3a in a partial area. In the example of FIG. 4, the pedestal portion 31 is arranged on the bottom surface of the concave portion 3a. With such a configuration, optical position adjustment (alignment) of the excitation light source 20, the optical element 30, and the wavelength conversion element 10 is facilitated.

  In addition, when the length of the excitation light source 20 and the wavelength conversion element 10 in the Z direction can be secured to some extent, the cooling plate 3 does not necessarily have to include the concave portion 3a.

  As described above, in the wavelength conversion element 10, the surface 13 (side surface 13) on which the excitation light L20 is incident is different from the surface 11 from which the fluorescent light L10 is emitted. Therefore, it is not necessary to separately provide an optical member for separating the excitation light L20 incident on the wavelength conversion element 10 and the fluorescence L10 emitted from the wavelength conversion element 10. Thereby, the small fluorescent light source device 1 is realized.

  Further, as described above, the wavelength conversion element 10 and the excitation light source 20 are arranged apart from each other in a direction orthogonal to the side surface 13, that is, along the optical axis direction of the excitation light L20. As a result, the heat dissipation of the wavelength conversion element 10 is improved, and the problem that the fluorescence conversion efficiency is reduced due to the temperature quenching is improved. Further, by arranging them separately from each other, even when the wavelength conversion element 10 and the excitation light source 20 are mounted on the same cooling plate 3 as shown in FIG. Performance can be realized. Thereby, a compact fluorescent light source device 1 can be realized while achieving high cooling performance.

  In addition, when the excitation light source 20 is configured by an LD element, it is preferable to arrange the semiconductor layers so that the stacking direction d20 of the semiconductor layers coincides with the Z direction (see FIG. 5). FIG. 5 is a perspective view schematically showing the structure of the excitation light source 20. Excitation light L20 emitted from the emitter 21 of the excitation light source 20 travels to the side surface 13 of the wavelength conversion element 10. As described above, the side surface 13 of the wavelength conversion element 10 has a shape in which the length in the Z direction is shorter than the length in other directions. On the other hand, the emitter 21 is formed of an active layer made of a semiconductor, and has a shape whose thickness direction is shorter than the length in the other direction (Y direction in FIG. 5). By arranging the excitation light source 20 so that the stacking direction d20 of the semiconductor layers is in the Z direction, the excitation light L20 can be efficiently guided to the side surface 13.

  The fluorescent light source device 1 can realize various variations. Hereinafter, these aspects will be described. Note that the following variations can be appropriately combined.

  <1> As shown in FIG. 6, the wavelength conversion element 10 may have a reflection film 61 formed on the surface 12 opposite to the surface 11 constituting the extraction surface of the fluorescent light L10. FIG. 6 corresponds to a partially enlarged view of FIG. The reflection film 61 is made of a material exhibiting reflection characteristics with respect to the fluorescent light L10, and is made of, for example, a metal material such as Ag or a dielectric multilayer film. More specifically, in the wavelength conversion element 10, the surface 12 on which the reflection film 61 is formed and the cooling plate 3 may be fixedly bonded via the solder layer 62. The reflection film 61 corresponds to a “first reflection film”.

  According to this configuration, of the fluorescent light L10 generated in the wavelength conversion element 10, the fluorescent light L10 that has proceeded to the opposite side (the surface 12 side) to the surface 11 constituting the extraction surface is reflected to the surface 11 side. You can go. Thereby, the extraction efficiency of the fluorescent light L10 is improved.

  The reflection film 61 is preferably made of a material exhibiting a reflection characteristic with respect to the excitation light L20 together with the fluorescence L10. The excitation light L20 emitted from the excitation light source 20 is incident on the wavelength conversion element 10 via the side surface 13. At this time, there is a possibility that a part of the excitation light L20 proceeds to the cooling plate 3 side without contributing to the conversion to the fluorescence L10. Since the reflection film 61 showing the reflection characteristic for the excitation light L20 is formed between the wavelength conversion element 10 and the cooling plate 3, the excitation light L20 traveling to the cooling plate 3 side is re-entered into the wavelength conversion element 10. The light can be reflected to contribute to the excitation of the fluorescent material contained in the wavelength conversion element 10. As a result, the fluorescence generation efficiency (fluorescence conversion efficiency) in the wavelength conversion element 10 is improved.

  In this case, when the area of the surface 11 of the wavelength conversion element 10 is S1 and the area of the side surface 13 of the wavelength conversion element 10 is S2, preferably 2 × S1> S2. That is, of the surfaces of the wavelength conversion element 10, the area of the surface on which the excitation light L20 is incident is smaller than twice the area of the surface from which the fluorescent light L10 is extracted. With this configuration, the amount of fluorescence L10 generated in the wavelength conversion element 10 emitted from the side surface 13 different from the extraction surface is suppressed, and the extraction efficiency of the fluorescence L10 is increased.

  <2> As shown in FIG. 7, the wavelength conversion element 10 may have a reflection film 63 that reflects the fluorescence L10 formed on the side surface 13. The reflective film 63 shows a transmittance with respect to the excitation light L20 and shows a reflectivity with respect to the fluorescent light L10. The reflection film 63 is composed of, for example, a dielectric multilayer film.

  By providing this reflection film 63 on the side surface 13, the excitation light L 20 is incident on the wavelength conversion element 10, while the fluorescence L 10 generated in the wavelength conversion element 10 and traveling toward the side surface 13 has the wavelength again. It can be returned to the conversion element 10. Accordingly, the amount of light emitted from the side surface 13 of the fluorescent light L10 is suppressed, and the efficiency of the fluorescent light L10 extracted from the surface 11 is increased. The reflection film 63 corresponds to a “second reflection film”.

  <3> As shown in FIG. 8, the wavelength conversion element 10 may have an anti-reflection layer 64 formed on the side of the surface 11 constituting the extraction surface of the fluorescent light L10. The antireflection layer 64 can be realized by a laminate of a plurality of dielectric multilayer films having different refractive indexes or a fine uneven structure (moth-eye structure).

  Since the antireflection layer 64 is provided on the surface 11 constituting the extraction surface of the fluorescent light L10, the amount of the fluorescent light L10 generated in the wavelength conversion element 10 is reflected by the surface 11 and returned to the wavelength conversion element 10 side. Is reduced, and the efficiency of the fluorescent light L10 extracted from the surface 11 is increased.

  FIG. 8 illustrates a structure in which the reflection film 61 is formed on the surface 12 side of the wavelength conversion element 10 and the antireflection layer 64 is formed on the surface 11 side, but the reflection film 61 is not provided. May be provided only with the anti-reflection layer 64.

  <4> The fluorescent light source device 1 may include a second light source 40 that emits light L40 having a wavelength different from the excitation light L20, separately from the excitation light source 20 (see FIG. 9). When the light L40 emitted from the second light source 40 is irradiated into the region 52 on the side surface 13 of the wavelength conversion element 10, the light L40 is extracted from the surface 11 together with the fluorescent light L10. The region 52 corresponds to a “second irradiation region”.

  Unlike the excitation light L20, the light L40 may indicate a wavelength that is not substantially converted into the fluorescence L10 in the wavelength conversion element 10. As an example, the excitation light L20 is a blue light having a peak wavelength of 400 nm or more and 500 nm or less, the fluorescent light L10 is a yellow light having a peak wavelength of 500 nm or more and 600 nm or less, and the light L40 emitted from the second light source 40 has a peak. Red light having a wavelength of 600 nm or more and 800 nm or less is used. Thereby, the combined light of the fluorescent light L10 and the light L40 emitted from the fluorescent light source device 1 is combined with the blue light to generate white light with high color rendering properties.

[Another embodiment]
Still another embodiment of the fluorescent light source device 1 will be described below.

  <1> In the above embodiment, the optical element 30 is composed of a plurality of lenses (32, 33). However, the optical element 30 only needs to have a function of causing the excitation light L20 emitted from the excitation light source 20 to enter the side surface 13 of the wavelength conversion element 10, and as long as the optical element 30 has the function of being incident on the lenses (32, 33). Is not limited. For example, as in the fluorescent light source device 1 shown in FIGS. 10 and 11, the optical element 30 may be configured by the optical waveguide 35. The optical waveguide 35 can be composed of, for example, an optical fiber, a rod integrator, or the like.

  Further, the optical element 30 may have a configuration including a lens 32 and / or a lens 33 in addition to the optical waveguide 35 (see FIG. 12). For example, in the configuration shown in FIG. 12, the excitation light L20 is collimated by the lens 32 and then condensed on the incident surface of the optical waveguide 35 by the lens 33. After that, the excitation light L20 travels through the optical waveguide 35 and then enters the side surface 13 of the wavelength conversion element 10.

  <2> According to the example illustrated in FIG. 1, the wavelength conversion element 10 is configured such that the excitation light L20 is incident on each region 51 on the side surface 13 from four directions. However, the direction of incidence of the excitation light L20 on the wavelength conversion element 10 is not limited to four directions.

  For example, the present invention includes a single excitation light source 20, and excitation light L20 emitted from the excitation light source 20 is incident on a predetermined region 51 on the side surface 13 of the wavelength conversion element 10 via the optical element 30. This does not exclude the aspect of the present invention. As another example, as illustrated in FIG. 13, the fluorescent light source device 1 includes the excitation light sources 20 at six positions, and the excitation lights L20 emitted from the respective excitation light sources 20 pass through different optical elements 30, respectively. Alternatively, the light may be incident on different regions 51 on the side surface 13 of the wavelength conversion element 10 in different directions.

  <3> In the above embodiment, the case where the wavelength conversion element 10 has a cylindrical shape has been described as an example. However, the surface 11 constituting the light extraction surface, the surface 12 facing the surface 11, the surfaces 11 and The shape of the wavelength conversion element 10 is arbitrary, as long as the shape has the side surface 13 connecting the 12. For example, when the wavelength conversion element 10 has a rectangular parallelepiped shape, the wavelength conversion element 10 has a square shape when viewed from the Z direction, as shown in FIG. In this case, the side surface 13 of the wavelength conversion element 10 includes a plurality of planes, and the excitation light L20 can be incident on the region 51 on each side surface 13.

  As in the case where the wavelength conversion element 10 has a rectangular parallelepiped shape, when the surface 11 forming the extraction surface of the fluorescent light L10 has a polygonal shape, the surface 11 and the surface 12 facing the surface 11 are defined by the sides of the surface 11 The distance may be shorter than the length or the diameter of the circumscribed circle of the surface 11. On the other hand, as shown in FIG. 1, when the surface 11 of the wavelength conversion element 10 has a circular shape, it is assumed that the surface 11 and the surface 12 are separated by a distance shorter than the length of the diameter of the surface 11. No problem.

  The side surface 13 on which the excitation light L20 is incident may be a curved surface, a plurality of flat surfaces, or a configuration including a flat surface and a curved surface. In the wavelength conversion element 10, the sizes of the surface 11 and the surface 12 do not necessarily have to match.

  <4> The fluorescent light source device 1 may extract the excitation light L20 in addition to the fluorescent light L10 from the surface 11 constituting the light extraction surface of the wavelength conversion element 10. Conversely, the fluorescent light source device 1 may not substantially extract the excitation light L20 from the surface 11. Whether to extract the excitation light L20 from the surface 11 of the wavelength conversion element 10 can be appropriately designed by changing the amount and density of the phosphor contained in the wavelength conversion element 10 and the dimensions of the wavelength conversion element 10. .

  <5> In the above embodiment, the case where the excitation light source 20 is configured by an LD element has been described. However, the excitation light source 20 may be configured by an LED element.

1: Fluorescent light source device 3: Cooling plate 3a: Concave portion 10: Wavelength conversion element 11, 12: Surface of wavelength conversion element 13: Side surface of wavelength conversion element 20: Excitation light source 21: Emitter of excitation light source 30: Optical element 31: Base Parts 32, 33: Lens 35: Optical waveguide 40: Second light source 51: First irradiation area 52: Second irradiation area 61: Reflective film 62: Solder layer 63: Reflective film 64: Antireflection layer L10: Fluorescence L20: Excitation Light L40: Light emitted from the second light source

Claims (12)

A first surface, a second surface disposed at a position facing the first direction at a distance shorter than a side, a diameter, or a diameter of a circumscribed circle of the first surface with respect to the first surface; Having one surface and the second surface, and having a third surface non-parallel to the first surface and the second surface, and the first wavelength when light of the first wavelength is incident. A wavelength conversion element that generates fluorescence of a different second wavelength,
For the third surface of the wavelength conversion element, disposed at a position separated in a second direction perpendicular to the third surface, an excitation light source that emits the excitation light of the first wavelength,
An optical element disposed between the excitation light source and the third surface of the wavelength conversion element, and irradiating the excitation light to a first irradiation area on the third surface of the wavelength conversion element,
The fluorescence light source device, wherein the wavelength conversion element converts the excitation light into the fluorescence and emits the fluorescence from the first surface.   The fluorescent light source device according to claim 1, further comprising a cooling plate including a mounting surface on which the wavelength conversion element and the excitation light source are mounted.   The fluorescent light source device according to claim 2, wherein the optical element is fixedly arranged with respect to the cooling plate. The third surface of the wavelength conversion element, a plurality of planes, curved surfaces, or a group thereof,
The excitation light is incident on each of the plurality of first irradiation regions on the third surface, comprising a plurality of the excitation light sources, characterized in that, according to any one of claims 1 to 3, The fluorescent light source device according to claim 1.   The fluorescent light source device according to claim 4, wherein a total area of the first surface and the second surface is larger than a total area of the third surface.   The fluorescent light source device according to any one of claims 1 to 5, wherein the optical element includes a condensing optical system that condenses the excitation light on the first irradiation area.   The fluorescent light source device according to claim 1, wherein the optical element includes an optical waveguide that guides the excitation light to the first irradiation area. The excitation light source includes a semiconductor laser device in which a plurality of semiconductor layers are stacked,
The fluorescent light source device according to claim 1, wherein a stacking direction of the semiconductor layers is substantially parallel to the first direction.   9. The device according to claim 1, further comprising a first reflection film that is disposed in contact with the outside of the second surface of the wavelength conversion element and reflects the light of the second wavelength. 10. The fluorescent light source device according to item 1.   10. The light-emitting device according to claim 1, further comprising a second reflective film that transmits the light of the first wavelength and reflects the light of the second wavelength on the third surface of the wavelength conversion element. The fluorescent light source device according to claim 1.   The fluorescent light source according to any one of claims 1 to 10, further comprising an anti-reflection layer for preventing reflection of the second wavelength light on the first surface of the wavelength conversion element. apparatus. The third surface of the wavelength conversion element, disposed at a position separated in the second direction, comprising a second light source that emits light having a wavelength different from both the first wavelength and the second wavelength,
The light emitted from the second light source is irradiated on a second irradiation area different from the first irradiation area on the third surface of the wavelength conversion element. The fluorescent light source device according to any one of claims 1 to 11.

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