JP7145382B2 - Fluorescent light source device - Google Patents

Description

The present invention relates to a fluorescence light source device containing an excitation light source and a phosphor.

Conventionally, a technique is known 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 does not face the incident surface. (See Patent Document 1 below). According to this document, it is said that the brightness of the fluorescence is enhanced because the area of the surface of the phosphor from which the fluorescence is emitted can be made smaller than the area of the surface of the phosphor on which the excitation light is incident.

As another technique, there is a technique of arranging a compound parabolic concentrator (CPC) on the emitting surface side of the phosphor in order to increase the efficiency of extracting fluorescence from the rod-shaped phosphor. known (see Patent Document 2 below).

Japanese Patent Publication No. 2008-521233 WO2009/021079

In the technique disclosed in Patent Document 1, the fluorescent material is made plate-shaped or rod-shaped to have a length in a certain direction (hereinafter referred to as "longitudinal direction"). Fluorescence generated in the phosphor propagates along the longitudinal direction while undergoing total internal reflection, and is led to the exit surface side. However, according to this method, as shown in FIG. 29, part of the fluorescence L100 that has propagated in the phosphor 100 in the d1 direction and reached the exit surface 101 is also totally reflected at the exit surface 101. It can happen that it is put back into the phosphor 100 again. In other words, the proportion of fluorescence L100 generated in phosphor 100 that can be extracted to the outside decreases.

The technique of Patent Literature 2 is intended to increase the fluorescence extraction efficiency. For example, as shown in FIG. 30, consider a case where a collector 110 is arranged so as to be connected to the emission surface 101 side of the phosphor 100 shown in FIG. Strictly speaking, in FIG. 30, the emission surface 101 of the phosphor 100 is a surface that guides the fluorescence L100 to the collector 110, and is not a surface that emits the fluorescence L100 to the outside. 29, the term "outgoing surface 101" is used in the sense of emitting light.

Fluorescence L100 incident on the exit surface 101 of the phosphor 100 at an incident angle _θa exceeding the critical angle is totally reflected by the exit surface 101 and returned to the phosphor 100 side in the configuration of FIG. On the other hand, in the configuration of FIG. 30, the light enters the collector 110 as it is and is totally reflected by the side surface 111 of the collector 110 . Concentrator 110 has a shape that widens toward exit surface 112 . For this reason, the incident angle θ _b when the fluorescence L100 reflected by the side surface 111 is incident on the exit surface 112 can be significantly lower than the incident angle θ _a on the exit surface 101 of the phosphor 100, and is less than the critical angle. can do. As a result, the total reflection of the fluorescence L100 on the emission surface 112 of the collector 110 is suppressed, and the amount of the fluorescence L100 extracted to the outside increases.

However, as shown in FIG. 30, the concentrator 110 has a shape that widens from the side closer to the phosphor 100 toward the emission surface 112 . As a result, the area of the emission surface 112 from which the fluorescence L100 is actually emitted becomes large, which reduces the effect of increasing the brightness and increases the scale of the optical system arranged in the subsequent stage.

SUMMARY OF THE INVENTION An object of the present invention is to realize a fluorescence light source device that enhances fluorescence extraction efficiency while suppressing an increase in the area of the exit surface.

The fluorescence light source device according to the present invention is
The first direction is the longitudinal direction, and the width in the second direction orthogonal to the first direction is substantially the same as the width approaches the first end, which is one end in the first direction, from a predetermined location. a phosphor that has a shape including an inclined surface or curved surface that decreases to
an excitation light source that emits excitation light of the first wavelength, arranged along the first direction on the outer side of the phosphor in the second direction;
It is made of a material that exhibits transparency to the fluorescence and has a refractive index value that is higher than the refractive index of air and lower than the refractive index of the phosphor. A first feature is that it comprises a glass member which is arranged so that its surfaces are joined to each other.

In the fluorescence light source device, the phosphor has an inclined surface or curved surface such that the width in the second direction decreases from a predetermined location toward the first end side. As a result, the fluorescence, which is totally reflected in the phosphor and propagates toward the first end, has an incident angle with respect to the surface of the phosphor that decreases each time it repeats reflection on the inclined surface or the curved surface.

Of the surfaces of the phosphor, an inclined surface or a curved surface (hereinafter referred to as "surface A1") is in contact with a glass member made of a material having a higher refractive index than air and a lower refractive index than the phosphor. . On the other hand, among the surfaces of the phosphor, the surface arranged on the side facing the surface A1 in the second direction (hereinafter referred to as "surface B1") is in contact with air. Therefore, the critical angle on the surface A1 of the phosphor is larger than the critical angle on the surface B1 of the phosphor.

Therefore, in the phosphor, the fluorescence propagated to the first end side while repeating total reflection on the surface A1 and the surface B1 is incident on the surface A1 at an angle less than the critical angle at a certain point of time and enters the glass member. proceed to Since the glass member has a lower refractive index than the phosphor, the traveling direction of the fluorescence in the glass member is refracted in a direction closer to the first direction than when the fluorescence was incident on the surface A1 of the phosphor immediately before. As a result, the fluorescent light can travel substantially in the first direction through the glass member and can be extracted in the first direction from the end face of the glass member on the first end side.

That is, according to this configuration, fluorescence is extracted in the first direction from the surface of the phosphor on the first end side and the surface of the glass member on the first end side.

Then, as described above, the phosphor has a shape including an inclined surface or curved surface that substantially decreases as it approaches the first end from a predetermined location, and the glass member is aligned with this inclined surface or curved surface. The faces of the parts are joined and arranged. Therefore, according to the above configuration, although the glass member is additionally provided, the expansion of the width in the second direction in the vicinity of the first end is suppressed, so that high-brightness fluorescence can be extracted.

In the above configuration, the length of the width in the second direction in the region where the inclined surface or the curved surface of the phosphor is not formed is the inclined surface or the curved surface of the phosphor. It may be substantially equal to the sum of the width of the region in the second direction and the width of the glass member in the second direction. According to such a configuration, the surface of the fluorescent material on the exit surface side and the surface of the glass member can be formed on substantially the same plane, so that the design of the subsequent optical system can be facilitated.

The fluorescence light source device according to the present invention is
The first direction is the longitudinal direction, and the width in the second direction orthogonal to the first direction is substantially the same as the width approaches the first end, which is one end in the first direction, from a predetermined location. a phosphor that has a shape including an inclined surface or curved surface that decreases to
an excitation light source that emits excitation light of the first wavelength, arranged along the first direction on the outer side of the phosphor in the second direction;
A second feature further comprising: a mirror member exhibiting reflectivity with respect to the fluorescence, arranged at a position outside the region in which the inclined surface or the curved surface of the phosphor is formed in the second direction. and

Also in the above configuration, the phosphor has an inclined surface or a curved surface such that the width in the second direction decreases from a predetermined location toward the first end, which is the end on the exit surface side. there is At this time, as described above, the incident angle of the fluorescence that is totally reflected in the phosphor and propagated toward the first end decreases with each repetition of total reflection.

Here, the incident angle when incident on the inclined surface or curved surface (hereinafter referred to as "surface A2") among the surfaces of the phosphor is It is smaller than the angle of incidence when it is incident on the surface arranged on the opposite side (hereinafter referred to as "surface B2"). As a result, in the phosphor, the fluorescence propagated to the first end side while being repeatedly totally reflected by the surfaces A2 and B2 enters the surface A2 at an angle less than the critical angle at a certain point, and is emitted outward in the second direction from the At this time, since the air has a lower refractive index than the phosphor, the traveling direction of the fluorescence is refracted in a direction closer to the first direction than when it was incident on the surface A2 of the phosphor immediately before.

According to the above configuration, the mirror member is provided at the outer position in the second direction of the region of the phosphor where the inclined surface or curved surface is formed. When the fluorescence is incident on the mirror member, the fluorescence is reflected by the mirror member and travels toward the phosphor side again, or is emitted outside in the second direction from between the mirror member and the phosphor. Of the fluorescence reflected by the mirror member and traveling again into the phosphor, part of the fluorescence propagates to the first end while repeating total reflection again between the surfaces B2 and A2 of the phosphor, and then propagates to another side. A portion of the fluorescence is again emitted from the surface A2 to the outside of the phosphor in the second direction. At a position close to the first end, the fluorescence emitted from the surface A2 to the outside of the phosphor in the second direction passes through the position of the first end of the phosphor in the first direction before reaching the mirror member. do. That is, the fluorescence can be extracted in the first direction from a position between the first end of the phosphor and the mirror member with respect to the second direction.

That is, according to this configuration, from the surface of the phosphor on the first end side and the space in the position between the surface of the phosphor on the first end side and the mirror member in the second direction, the Fluorescence is extracted at Then, similarly to the first characteristic configuration, the expansion of the width in the second direction in the vicinity of the first end is suppressed, and high-brightness fluorescence can be extracted.

Preferably, the mirror member has a reflective surface substantially perpendicular to the second direction. Here, "a reflective surface substantially orthogonal to the second direction" means that the absolute value of the angle between the reflective surface and a plane that is completely orthogonal to the second direction is 0° or more and 10° or less. It does not matter if it indicates something. Also, the reflecting surface does not have to be perfectly flat, and may have a curved surface or a curved portion. When there is a curved surface or curved portion, the absolute value of the angle formed by the tangential plane of the curved surface or curved portion and the plane that is completely orthogonal to the second direction may be 0° or more and 10° or less. . The reflective surface only needs to have the function of returning fluorescence emitted from the side surface of the phosphor to the outside in the second direction to the phosphor side.

The fluorescence light source device having the first characteristic configuration is arranged at a position outside the region in which the inclined surface or the curved surface of the phosphor is formed in the second direction, and the reflectivity to the fluorescence may be provided with a mirror member that indicates .

The mirror member is also arranged at a position outside the inclined surface or the curved surface of the phosphor in a third direction perpendicular to the first direction and the second direction. It may have a U-shape (U-shape) or a square shape when folded.

As described above, when the incident angle with respect to the inclined surface or curved surface of the phosphor becomes less than the critical angle, the fluorescence guided to the first end side (the emission surface side) while repeating total reflection in the phosphor becomes It passes through the inclined surface or the curved surface and is emitted to the outside in the second direction of the phosphor. At this time, part of the fluorescence returned to the phosphor side by the mirror member arranged outside in the second direction of the phosphor is incident on the side surface of the phosphor at a position different from the inclined surface or the curved surface. There are cases. More specifically, part of the fluorescence may be incident on the surface (side surface) located at the end of the phosphor in the third direction orthogonal to both the first direction and the second direction. If the incident angle at this time is less than the critical angle, the light will be emitted to the outside in the third direction of the phosphor through the same side surface.

According to the above configuration, since the mirror member is also arranged at the outer position in the third direction with respect to the inclined surface or the curved surface of the phosphor, the fluorescent light is emitted from the side surface of the phosphor to the outer side in the third direction. Even when the light is emitted, it can be returned to the phosphor side, and the fluorescence extraction efficiency can be further increased.

When mirror members are provided at two locations facing each other to sandwich the phosphor in the second direction and at two locations facing each other to sandwich the phosphor in the third direction, the mirror members are placed from the first direction. When viewed, it shows a square shape. Below, the mirror member arranged at the outer position in the second direction of the phosphor is referred to as "first mirror member". According to the above configuration, part of the fluorescence that passes through the inclined surface or the curved surface in the second direction, is reflected by one of the first mirror members, and is returned to the phosphor side is reflected in the second direction of the inclined surface or the curved surface. Even if the incident light is incident on the side surface located on the opposite side of the above at an angle of incidence less than the critical angle, it can be returned to the phosphor side again by the other first mirror member.

Even if the first mirror member is arranged only at one outer position in the second direction of the region where the inclined surface or the curved surface is formed, the position opposite to the first mirror member By arranging a plurality of excitation light sources, it is possible to realize a reflection function similar to that of the first mirror member. In this case, the mirror member exhibits a U-shape (U-shape) when viewed from the first direction.

The phosphor has a second end that is an end opposite to the first end with respect to the first direction when viewed from a third direction orthogonal to the first direction and the second direction to the predetermined portion may be rectangular, and the region from the predetermined portion to the first end may be trapezoidal, triangular, arc-shaped, or elliptical-arc.

The fluorescence light source device is
a refractive optical system arranged at a position outside the first end of the phosphor and condensing the fluorescence emitted in the first direction from at least the first end of the phosphor;
and a post-stage optical system into which the fluorescence condensed by the refractive optical system is incident.

In this case, when the fluorescence light source device includes the glass member, the refractive optical system also collects the fluorescence emitted in the first direction from the end surface of the glass member on the first end side. I don't mind. Further, when the fluorescence light source device includes the mirror member, the refractive optical system emits light in the first direction from the spatial region between the phosphor and the mirror member with respect to the second direction. Fluorescence may also be condensed.

ADVANTAGE OF THE INVENTION According to the fluorescence light source device of this invention, while suppressing the expansion of the area of an output surface, the extraction efficiency of fluorescence is improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows typically the structure of 1st embodiment of the fluorescence light source device of this invention. It is a perspective view which shows typically the structure of the fluorescent substance and glass member which are contained in a fluorescence light source device. It is drawing which shows typically the movement of some fluorescence produced|generated within the fluorescent substance with which the fluorescence light source device of 1st embodiment is provided. It is a typical plan view when the fluorescence light source device of 1st embodiment is seen from the output surface side. It is a top view which shows typically another structure of 1st embodiment of the fluorescence light source device of this invention. It is a top view which shows typically another structure of 1st embodiment of the fluorescence light source device of this invention. It is a top view which shows typically another structure of 1st embodiment of the fluorescence light source device of this invention. FIG. 4 is a perspective view schematically showing another configuration of phosphors; FIG. 4 is a perspective view schematically showing another configuration of phosphors; FIG. 4 is a perspective view schematically showing another configuration of phosphors; It is a top view which shows typically another structure of 1st embodiment of the fluorescence light source device of this invention. It is a top view which shows typically the structure of 2nd embodiment of the fluorescence light source device of this invention. It is drawing which shows typically the movement of some fluorescence produced|generated within the fluorescent substance with which the fluorescence light source device of 2nd embodiment is provided. It is a typical top view when the fluorescence light source device of 2nd embodiment is seen from the output surface side. It is another typical top view when the fluorescence light source device of 2nd embodiment is seen from the output surface side. It is another typical top view when the fluorescence light source device of 2nd embodiment is seen from the output surface side. It is a top view which shows typically another structure of 2nd embodiment of the fluorescence light source device of this invention. FIG. 3 is a plan view schematically showing the structure of the fluorescence light source device used in Verification 1; 4 is a graph showing the results of Verification 1; 10 is another graph showing the results of Verification 1. FIG. FIG. 10 is another plan view schematically showing the structure of the fluorescence light source device used in Verification 1. FIG. 10 is another graph showing the results of Verification 1. FIG. FIG. 10 is a plan view schematically showing the structure of the fluorescence light source device used in Verification 2; 9 is a graph showing the results of Verification 2; FIG. 10 is a plan view schematically showing the structure of the fluorescence light source device used in Verification 3; 9 is a graph showing the results of Verification 3; It is drawing which shows typically the structure of the fluorescence light source device of another embodiment. It is drawing which shows typically the structure of the fluorescence light source device of another embodiment. It is typical drawing for demonstrating the problem of the conventional fluorescence light source device. It is another typical drawing for demonstrating the problem of the conventional fluorescence light source device.

An embodiment of a fluorescence light source device according to the present invention will be described with reference to the drawings. It should be noted that the following drawings are schematic illustrations, and the dimensional ratios on the drawings do not necessarily match the actual dimensional ratios, nor do the dimensional ratios between the drawings necessarily match.

The rays illustrated in the drawing schematically show the movement of one principal ray included in the ray bundle. However, the incident angle, reflection angle, and refraction angle of a ray when the ray is reflected or refracted on a certain incident surface may be exaggerated for convenience of explanation, and are not necessarily correct.

[First embodiment]
FIG. 1 is a plan view schematically showing the configuration of the first embodiment of the fluorescence light source device according to the present invention. As shown in FIG. 1 , the fluorescence light source device 1 includes a phosphor 10 , a glass member 20 and an excitation light source 30 . FIG. 2 is a perspective view schematically showing structures of the phosphor 10 and the glass member 20 in FIG.

As shown in FIGS. 1 and 2, in this embodiment, the phosphor 10 has a shape whose longitudinal direction is the X direction. More specifically, the phosphor 10 has a shape in which the length in the X direction is longer than the length in the Y direction and the Z direction, which are two directions orthogonal to the X direction. In the following description, the XYZ coordinate system shown in FIGS. 1 and 2 will be used as appropriate.

In this specification, when describing a certain direction, it is simply referred to as "X direction", "Y direction", or "Z direction" when there is no need to distinguish between positive and negative. Also, when it is necessary to distinguish between positive and negative, it is described as “+X direction”, “−X direction”, etc. as appropriate.

The X direction corresponds to the "first direction", the Y direction corresponds to the "second direction", and the Z direction corresponds to the "third direction".

Phosphor 10 has an inclined surface 13 . More specifically, as the phosphor 10 approaches the end (first end 11) where the X coordinate is x2 from the place where the X coordinate is x1 (corresponding to the “predetermined place”), It has an inclined surface 13 such that the width 10y in the Y direction is reduced.

In the example illustrated in FIG. 1 , the phosphor 10 has an area from the point where the X coordinate is x1 to the second end 12 opposite to the first end 11 (the end where the X coordinate is x0). shows a shape in which the width 10y in the Y direction is the same. More specifically, when viewed from the Z direction, the phosphor 10 has a rectangular shape in the X coordinate region from x0 to x1, and has a trapezoidal shape in the X coordinate region from x1 to x2.

The phosphor 10 includes a material that generates fluorescence L10 having a wavelength different from that of the excitation light L30 when the excitation light L30 emitted from the excitation light source 30 is incident thereon. Also, the refractive index of the phosphor 10 is higher than that of air and the glass member 20 . Examples of such materials include YAG (Y ₃ Al ₅ O ₁₂ :Ce ³⁺ ), β-sialon (SrSiAlON:Eu ²⁺ ), LuAG (Lu ₃ Al ₅ O ₁₂ :Ce ³⁺ ), and the like. . However, in the present invention, the constituent material of the phosphor 10 is a material that generates fluorescence L10 having a wavelength different from that of the excitation light L30 when the excitation light L30 is incident, and has a refractive index higher than that of the air and the glass member 20. Optional as long as it contains expensive materials.

The glass member 20 is made of a material having a lower refractive index than the phosphor 10 and a higher refractive index than air, and is transparent to the fluorescence L10. As an example, the glass member 20 is made of quartz glass, borosilicate glass, BK7, B270 (registered trademark), or the like. However, in the present invention, the constituent material of the glass member 20 is arbitrary as long as it exhibits transparency to the fluorescence L10, has a lower refractive index than the phosphor 10, and has a higher refractive index than air.

The glass member 20 is arranged such that a part of the surface of the glass member 20 is fixedly bonded to the inclined surface 13 of the phosphor 10 via, for example, an optical adhesive. In the example illustrated in FIG. 1, the glass member 20 exhibits a triangular shape when viewed in the Z direction. More specifically, as shown in FIGS. 1 and 2, the glass member 20 is arranged in the region from x1 to x2 with respect to the X coordinate.

As shown in FIG. 1, the fluorescence light source device 1 includes a plurality of excitation light sources 30 arranged along the X direction. In this embodiment, the excitation light source 30 is composed of an LED element. As a more specific example, the excitation light source 30 is an LED element including an active layer made of a nitride semiconductor such as GaN, InGaN, or AlInGaN, and having a peak wavelength of 400 nm or more and 500 nm or less. However, in the present invention, the wavelength of the excitation light L30 emitted by the excitation light source 30 is not limited.

Although not shown, a plurality of excitation light sources 30 may be arranged in the Z direction as well. Further, in the Y direction, a minute space may exist between the excitation light source 30 and the phosphor 10, and air may exist in the space.

The excitation light L30 emitted from the excitation light source 30 substantially travels in the Y direction and enters the phosphor 10 . This excitation light L30 is converted into fluorescence L10 while traveling through the phosphor 10 . The fluorescence L10 substantially diffuses in the X direction while repeating total reflection on the side surface of the phosphor 10 .

FIG. 3 schematically illustrates movement of light rays of the fluorescence L10a that is part of the fluorescence L10. The fluorescence L10a travels in the X direction toward the first end portion 11 side in the X direction while repeating total reflection in the phosphor 10 between the inclined surface 13 and the side surface 14 facing the inclined surface 13 in the Y direction. .

As described above, phosphor 10 has inclined surface 13 such that width 10y in the Y direction decreases as it approaches first end 11 in the X direction. Therefore, as the fluorescence L10 (L10a) is repeatedly reflected on the inclined surface 13, the incident angle θ _x when incident on the inclined surface 13 or the side surface 14 becomes smaller.

As described above, the inclined surface 13 of the phosphor 10 is in contact with the glass member 20 made of a material having a higher refractive index than air and a lower refractive index than the phosphor 10 . On the other hand, the side surface 14 of the phosphor 10 (the side surface facing the inclined surface 13 in the Y direction) is in contact with the air. Therefore, the critical angle at the inclined surface 13 is larger than the critical angle at the side surface 14 .

Therefore, in the phosphor 10, the fluorescence L10 that has propagated toward the first end portion 11 while being repeatedly totally reflected by the inclined surface 13 and the side surface 14 has an incident angle less than the critical angle with respect to the inclined surface 13 at a certain point in time. It may be incident at θ _x . FIG. 3 schematically illustrates a state in which the fluorescence L10a is incident on the inclined surface 13 at a certain point 17a at an incident angle θ _x that is less than the critical angle.

At the location 17a, the fluorescence L10a incident on the inclined surface 13 at an incident angle θ _x less than the critical angle is substantially not totally reflected and propagates into the glass member 20 . Since the glass member 20 has a lower refractive index than the fluorescent substance 10, the fluorescence L10a incident on the glass member 20 is refracted. More specifically, the fluorescence L10a travels in a direction with a smaller crossing angle with respect to the X direction than the traveling direction immediately before it enters the glass member 20 . As a result, the fluorescence L10 that has entered the glass member 20 travels toward the end portion 21 side of the glass member 20 .

As described above, the fluorescence L10 including the fluorescence L10a incident on the glass member 20 travels in a direction with a small crossing angle with respect to the X direction. angle is less than the critical angle. As a result, most of the fluorescence L10 that has entered the glass member 20 is emitted outside from the end portion 21 of the glass member 20 .

Some of the fluorescence L10 generated in the phosphor 10 reaches the first end portion 11 of the phosphor 10 while repeating total reflection between the inclined surface 13 and the side surface 14 . As a result, the fluorescence L10 is taken out from the first end 11 of the phosphor 10 and the end 21 of the glass member 20 to the outside. FIG. 4 is a schematic plan view when the fluorescence light source device 1 is viewed from the exit surface side, that is, in the -X direction. In FIG. 4, the region from which fluorescence L10 is extracted is hatched. Although FIG. 4 shows an aspect in which the pumping light sources 30 are arranged in three rows in the Z direction, the number of rows in which the pumping light sources 30 are arranged in the Z direction is merely an example. For example, the excitation light sources 30 may be arranged in only one row in the Z direction.

According to the fluorescence light source device 1, the phosphor 10 has the inclined surface 13, and the glass member 20 having a lower refractive index than the phosphor 10 is arranged so as to be bonded to the inclined surface 13. The amount of light of the fluorescence L10 incident on the first end portion 11 of the phosphor 10 at an angle equal to or greater than the critical angle is significantly reduced. As a result, the extraction efficiency of the fluorescence L10 is improved. This point will be described later with reference to examples.

Furthermore, as illustrated in FIG. 3, the phosphor 10 has a shape including an inclined surface 13 whose width 10y substantially decreases as it approaches the first end 11, and the glass member 20 is It is arranged so that a part of the surface is joined to this inclined surface 13 . For this reason, the fluorescent light source device 1 of the present embodiment additionally includes the glass member 20, but the expansion of the width in the Y direction near the first end 11, that is, on the exit surface side is suppressed. As a result, fluorescence L10 with high luminance can be extracted.

Another configuration of the fluorescence light source device 1 of the first embodiment will be described below.

<1> As shown in FIG. 5, even if the phosphor 10 has a structure in which the width 10y in the Y direction becomes smaller as it approaches the first end 11 over the entire region in the X direction. I do not care. In this case, as shown in FIG. 5, the glass member 20 may be arranged in the region from x0 to x2 with respect to the X coordinate.

<2> As shown in FIG. 6, when the phosphor 10 is viewed from the Z direction, the tilt angle of the inclined surface 13 may vary depending on the coordinate position in the X direction. That is, the inclined surface 13 may not be a single plane, and may be, for example, a folded plane. In the example shown in FIG. 6, when the phosphor 10 is viewed from the Z direction, the inclination angle of the inclined surface 13 in the region with the X coordinate from x1 to xa is the same as the inclined surface in the region with the X coordinate from xc to xd 13 different tilt angles. In this case, the glass member 20 may also have a bent plane corresponding to the bent plane of the phosphor 10 .

Furthermore, the inclined surface 13 may partially include a region parallel to the side surface 14 . In the example of FIG. 6, in the region where the X coordinate is from xb to xc, the inclined surface 13 is parallel to the side surface 14 facing in the Y direction.

In other words, the inclined surface 13 of the phosphor 10 may have a shape in which the width 10y in the Y direction substantially decreases toward the first end 11 in the X direction. Here, the width 10y “substantially decreases” means that the width 10y is the smallest at the first end 11 and the width 10y continuously decreases as it approaches the first end 11 in the X direction. This means that there is a region where

<3> As described above, the phosphor 10 may have a shape in which the width 10y in the Y direction substantially decreases toward the first end 11 in the X direction. Therefore, the phosphor 10 may have a curved surface 15 instead of the inclined surface 13, as shown in FIG. Also in this case, the glass member 20 may have a curved surface that joins the curved surface 15 of the phosphor 10 .

Moreover, the phosphor 10 may be configured to include both the inclined surface 13 and the curved surface 15 .

That is, the phosphor 10 may have a shape in which the width 10y in the Y direction substantially decreases as it approaches the first end 11 in the X direction. can. 8 to 10 show other examples of the phosphor 10. FIG.

Even when the fluorescence light source device 1 includes the phosphors 10 having the shapes illustrated in FIGS. do not have. In this case, for example, as shown in FIGS. 8 and 10, when the phosphor 10 exhibits a shape in which the width 10y in the Y direction decreases both in the + direction and in the −Y direction, the phosphor 10 The glass member 20 may be provided on the outside in the +Y direction and the outside in the -Y direction.

<4> The glass member 20 only needs to have a surface that joins with the inclined surface 13 or the curved surface 15. For example, as shown in FIG. FIG. 11 shows a case where part of the glass member 20 protrudes in the +Y direction with respect to the phosphor 10 . A part of the glass member 20 may protrude in the Z direction or in the X direction with respect to the phosphor 10 .

However, in consideration of the design of the subsequent optical system, the X coordinates of the end portion 21 of the glass member 20 constituting the exit surface and the first end portion 11 of the phosphor 10 are substantially the same. is preferred. That is, it is preferable that a part of the glass member 20 does not protrude in the +X direction with respect to the phosphor 10 .

[Second embodiment]
The second embodiment of the fluorescent light source device will be mainly described with respect to the points different from the first embodiment.

FIG. 12 is a plan view schematically showing the configuration of the second embodiment of the fluorescence light source device according to the present invention. As shown in FIG. 12, the fluorescence light source device 1 of this embodiment does not include the glass member 20 but includes the mirror member 40, unlike the first embodiment. Others are common to the fluorescence light source device 1 of the first embodiment.

The mirror member 40 is made of a material that reflects the fluorescence L10. In this embodiment, the mirror member 40 is arranged in a square shape so as to surround the phosphor 10 in the ±Y direction and the ±Z direction (see FIG. 14 described later). Hereinafter, the mirror member 40 arranged outside the phosphor 10 in the +Y direction will be referred to as a "mirror member 40a", and the mirror member 40 arranged outside the phosphor 10 in the -Y direction will be referred to as a "mirror member 40b". , the mirror member 40 arranged outside in the +Z direction with respect to the phosphor 10 is called a “mirror member 40c”, and the mirror member 40 arranged outside in the −Z direction with respect to the phosphor 10 is called a “mirror member 40d”. respectively. For convenience of illustration, only the mirror member 40a and the mirror member 40b are shown in FIG.

Here, when the mirror member 40b is arranged between the excitation light source 30 and the phosphor 10 with respect to the Y direction as in the present embodiment, the mirror member 40b serves as the excitation light emitted from the excitation light source 30. It may have a reflective surface that is transparent to L30 and reflective to fluorescence L10. Such a mirror member 40b can be composed of, for example, a dielectric multilayer film. Note that the other mirror members 40a, 40c, and 40d may be made of any material that reflects the fluorescence L10.

FIG. 13 schematically illustrates movement of rays of fluorescence L10b and L10c, which are part of the fluorescence L10.

Similar to the first embodiment, the phosphor 10 generates fluorescence L10 when the excitation light L30 is incident thereon. The fluorescence L10 advances in the X direction toward the first end portion 11 side in the X direction while repeating total reflection in the phosphor 10 between the inclined surface 13 and the side surface 14 facing the inclined surface 13 in the Y direction. . At this time, as the fluorescence L10 is repeatedly reflected on the inclined surface 13, the incident angle θ _x when incident on the inclined surface 13 or the side surface 14 becomes smaller.

Therefore, in the phosphor 10, the fluorescence L10 that has propagated toward the first end portion 11 while being repeatedly totally reflected by the inclined surface 13 and the side surface 14 has an incident angle less than the critical angle with respect to the inclined surface 13 at a certain point in time. It may be incident at θ _x . In FIG. 13, the fluorescence L10b is incident on the inclined surface 13 at a point 17b at an incident angle θ _x less than the critical angle, and the fluorescence L10c is incident on the inclined surface 13 at another point 17c at an angle less than the critical angle. is schematically illustrated in the case of incident at an incident angle θ _x of .

At the point 17c, the fluorescence L10c incident on the inclined surface 13 at an incident angle θ _x less than the critical angle is substantially not totally reflected, and is emitted from the inclined surface 13 of the phosphor 10 to the outside of the phosphor 10. be done. Air exists outside the phosphor 10, and since the air has a lower refractive index than the phosphor 10, the fluorescence L10c emitted from the inclined surface 13 of the phosphor 10 to the outside is directed in a direction having a small crossing angle with respect to the X direction. change direction to As a result, the light is emitted in the X direction from between the first end portion 11 of the phosphor 10 and the mirror member 40a.

Further, at the location 17b, the fluorescence L10b incident on the inclined surface 13 at an incident angle θ _x less than the critical angle is substantially not totally reflected, and is reflected from the inclined surface 13 of the phosphor 10 to the outside of the phosphor 10. emitted to At this time, like the fluorescence L10c, the fluorescence L10b travels in a direction with a smaller crossing angle with respect to the X direction. However, since the location 17b is located in front of the first end 11 of the phosphor 10 in the X direction, the fluorescence L10b is incident on the mirror member 40a before reaching the position where the X coordinate indicates x2. be. At this time, the fluorescence L10b is reflected by the mirror member 40a and emitted in the X direction from between the first end portion 11 of the phosphor 10 and the mirror member 40a.

Some of the fluorescence L10 generated in the phosphor 10 is emitted from the inclined surface 13 to the outside of the phosphor 10 and returned to the phosphor 10 after being reflected by the mirror member 40a. Some of this fluorescence L10 may be incident on the side surface 14 at an angle less than the critical angle. However, as described above, in this embodiment, since the mirror member 40b is also provided outside the side surface 14 of the phosphor 10, when the fluorescence L10 emitted from the side surface 14 to the outside of the phosphor 10 exists However, this fluorescence L10 can be returned to the phosphor 10 side again. That is, the fluorescence L10 is reflected by one or both of the mirror member 40a arranged outside the phosphor 10 in the +Y direction and the mirror member 40b arranged outside the phosphor 10 in the −Y direction. After that, there may be some emitted in the X direction from between the first end portion 11 of the phosphor 10 and the mirror member 40a.

By the way, some of the fluorescence L10 generated in the phosphor 10 travels toward the first end portion 11 of the phosphor 10 while repeating total reflection on two side surfaces of the phosphor 10 parallel to the YX plane. . Here, similarly, when the fluorescence L10 is incident on the side surface of the phosphor 10 at an incident angle less than the critical angle, the fluorescence L10 is emitted to the outside of the phosphor 10 from the side surface. However, even in such a case, the mirror members 40 (40c, 40d) are also arranged outside the phosphor 10 in the ±Z direction. It can be returned to the 10th side.

As in the case of the first embodiment, the fluorescence L10 generated in the phosphor 10 reaches the first end portion 11 of the phosphor 10 while repeating total reflection between the inclined surface 13 and the side surface 14. things also exist. As a result, the fluorescence L10 is emitted outside from the first end 11 of the phosphor 10 and from the position between the first end 11 of the phosphor 10 and the mirror member 40 (40a).

FIG. 14 is a schematic plan view of the fluorescence light source device 1 of the second embodiment when viewed from the exit surface side, that is, in the -X direction. In FIG. 14, the region from which fluorescence L10 is extracted is schematically indicated by hatching. In this embodiment, since there is a space between the inclined surface 13 of the phosphor 10 and the mirror member 40 in the Y direction, as shown in FIG. , the inclined surface 13 of the phosphor 10 is displayed.

According to the fluorescence light source device 1 of the present embodiment, the fluorescent substance 10 is provided with the inclined surface 13, and the air having a low refractive index is in contact with the inclined surface 13, so that the first end portion of the fluorescent substance 10 11 at an angle equal to or greater than the critical angle is significantly reduced. Furthermore, by arranging the mirror member 40 outside the inclined surface 13 in the Y direction, the fluorescence L10 emitted from the inclined surface 13 in the Y direction can also be guided to the emission surface side. The extraction efficiency of is improved. This point will be described later with reference to examples.

Also in the fluorescence light source device 1 of the present embodiment, the phosphor 10 has a shape including an inclined surface 13 in which the width 10y substantially decreases as the first end portion 11 is approached. Here, although the fluorescence light source device 1 of the present embodiment includes the mirror member 40, the mirror member 40 is merely arranged to surround the outer periphery of the phosphor 10, so that the area of the exit surface is expanded. not something to do. As a result, fluorescence L10 with high luminance can be extracted.

Another configuration of the fluorescence light source device 1 of the second embodiment will be described below.

<1> When the fluorescence light source device 1 has a large number of excitation light sources 30 arranged on the XZ plane related to the outside in the -Y direction of the phosphor 10, the excitation light source 30 illuminates the side surface of the phosphor 10 A function of reflecting the fluorescence L10 emitted in the -Y direction from 14 in the +Y direction may be realized. At this time, the fluorescence light source device 1 may not include the mirror member 40b. In this case, as shown in FIG. 15, the mirror member 40 (40a, 40c, 40d) has a shape (U-shaped shape or U-shape).

Of the fluorescence L10 traveling inside the phosphor 10, the fluorescence L10 emitted outside the phosphor 10 before the X coordinate reaches the position of the value x2 is emitted from the inclined surface 13 in the +Y direction. The amount of light of fluorescence L10 is the largest. Therefore, at least the fluorescence light source device 1 may be provided with a mirror member 40 (40a) (see FIG. 16).

<2> As shown in FIG. 17, the mirror member 40 may be arranged only outside the phosphor 10 in the region where the inclined surface 13 exists. In other words, the mirror member 40 may not be provided in the region outside the phosphor 10 and in the region where the X coordinates are from x0 to x1.

<3> Each variation of the shape of the phosphor 10 provided in the fluorescence light source device 1 described above in the first embodiment can be similarly applied to the phosphor 10 provided in the fluorescence light source device 1 of the second embodiment. be.

[Example]
Below, according to the fluorescence light source device 1 which concerns on this invention, it demonstrates with reference to a simulation result about the extraction efficiency of fluorescence L10 improving.

(Verification 1)
A simulation was performed assuming the fluorescence light source device 1 of the first embodiment. That is, the fluorescence light source device 1 having the glass member 20 was used as the object of the simulation.

<Setting condition 1>
In the fluorescence light source device 1 used for the simulation, as shown in FIG. 18 , the length w1 in the X direction of the phosphor 10 provided in the fluorescence light source device 1 is 10 mm, and the shape related to the second end 12 side was 1 mm x 1 mm. Further, the distance w2 between the X coordinate x1, which is the starting point of the inclined surface 13 of the phosphor 10 in the X direction, and the X coordinate x2 of the first end portion 11 was set to 6.67 mm. That is, the distance between the coordinates x1 and x2 was set to 2/3 of the distance between the coordinates x0 and x2 in the X direction.

<Setting condition 2>
The length w1 in the X direction of the phosphor 10 provided in the fluorescence light source device 1 is 120 mm, and the X coordinate x1, which is the starting point in the X direction of the inclined surface 13 of the phosphor 10, and the X coordinate x2 of the first end 11 The conditions were the same as the setting condition 1 except that the distance w2 between the and was set to 80 mm. That is, in setting condition 2, the shape of the phosphor 10 is longer and narrower in the X direction than in setting condition 1. FIG.

<Results>
Under the above setting conditions, the extraction efficiency of the fluorescence L10 was evaluated when the length t in the Y direction of the phosphor 10 at the first end 11 was varied from 0 mm to 1 mm. The results under setting condition 1 are shown in FIG. 19, and the results under setting condition 2 are shown in FIG.

Note that the case where the length t=0 mm corresponds to the case where the end portion at the position where the X coordinate is x2 is entirely composed of the glass member 20 . Also, the case where the length t=1 mm corresponds to the case where the glass member 20 does not exist at all. By changing the length t between 0 mm and 1 mm, the inclination angle of the inclined surface 13 is changed.

Further, the extraction efficiency of the fluorescence L10 is the ratio of the light amount of the fluorescence L10 extracted in the X direction from the phosphor 10 to the light amount of the fluorescence L10 generated when the excitation light L30 from the excitation light source 30 is incident on the phosphor 10. ratio.

According to FIG. 19, when t = 1 mm, i.e., when the glass member 20 is not present, when the glass member 20 is provided, i.e., the fluorescence light source device 1 of the first embodiment takes out the fluorescence L10 It can be seen that the efficiency is improved.

Moreover, according to FIG. 19, it is confirmed that the extraction efficiency of the fluorescence L10 is gradually lowered by decreasing the value of t from 0.75 mm. As a result, as the inclination angle of the inclined surface 13 gradually increases, part of the fluorescence L10 that has propagated from the phosphor 10 into the glass member 20 passes through the glass member 20 in the ±Y direction or the ±Z direction. It is presumed that this means that the amount of light emitted in the direction has increased. However, even in this case, it is confirmed that the extraction efficiency of the fluorescence L10 is greatly improved as compared with the case of t=1 mm.

In the results shown in FIG. 20, similarly to FIG. 19, when t=1 mm, that is, when the glass member 20 is not present, when the glass member 20 is provided, that is, when the fluorescent light source of the first embodiment It can be seen that the device 1 has a higher extraction efficiency of the fluorescence L10.

Incidentally, according to the results of FIG. 20, there is not much difference in the extraction efficiency of the fluorescence L10 between when t=0.75 mm and when t=0 mm. This result is presumed to be due to the glass member 20 exhibiting an extremely elongated shape with respect to the X direction under setting condition 2. FIG. More specifically, when t=0 mm, that is, even when the end portion at the position of the X coordinate x2 is entirely composed of the glass member 20, the inclination angle of the inclined surface 13 becomes gentle. Therefore, even when t=0 mm, the amount of light emitted in the ±Y direction or ±Z direction through the glass member 20 out of the fluorescence L10 generated in the phosphor 10 is t = 0.75 mm, and it is inferred that there is not much difference.

(Verification 2)
Similar to Verification 1, a simulation was performed assuming the fluorescence light source device 1 of the first embodiment. That is, the fluorescence light source device 1 having the glass member 20 was used as the object of the simulation.

<Setting conditions>
In the fluorescence light source device 1 used for the simulation, as shown in FIG. 21 , the length w1 in the X direction of the phosphor 10 provided in the fluorescence light source device 1 is 10 mm, and the shape related to the second end 12 side was 1 mm x 1 mm. Moreover, the length t in the Y direction of the phosphor 10 at the first end portion 11 was set to 0.5 mm.

<Results>
Under the above setting conditions, the distance w3 between the X coordinate x0 of the second end 12 of the phosphor 10 and the X coordinate x1, which is the starting point of the inclined surface 13 of the phosphor 10 in the X direction, is set to 0 mm to 10 mm. The extraction efficiency of fluorescence L10 was evaluated when changing to . The results are shown in FIG.

Note that the case where the distance w3=10 mm corresponds to the case where the fluorescence light source device 1 does not include the glass member 20 . That is, only this case corresponds to the case of t=1 mm. By changing the value of the distance w3 between 0 mm and 10 mm, the inclination angle of the inclined surface 13 is changed.

In the results shown in FIG. 22, similarly to FIGS. 19 and 20, compared with the case where the glass member 20 is not present (w3=10 mm), the fluorescence It can be seen that the light source device 1 has a higher extraction efficiency of the fluorescence L10.

(Verification 3)
A simulation was performed assuming the fluorescence light source device 1 of the second embodiment. That is, the fluorescent light source device 1 including the mirror member 40 was used as the simulation target. More specifically, the fluorescence light source device 1 provided with the mirror members 40 (40a, 40b, 40c, 40d) on the four sides of the outer periphery of the phosphor 10 was simulated.

<Setting conditions>
In the fluorescence light source device 1 used for the simulation, as shown in FIG. 23, the length w1 in the X direction of the phosphor 10 provided in the fluorescence light source device 1 is 10 mm, and the shape related to the second end 12 side was 1 mm x 1 mm. Further, the distance w2 between the X coordinate x1, which is the starting point of the inclined surface 13 of the phosphor 10 in the X direction, and the X coordinate x2 of the first end portion 11 was set to 6.67 mm. That is, the distance between the coordinates x1 and x2 was set to 2/3 of the distance between the coordinates x0 and x2 in the X direction.

<Results>
Under the above setting conditions, the extraction efficiency of the fluorescence L10 was evaluated when the length t in the Y direction of the phosphor 10 at the first end 11 was varied from 0 mm to 1 mm. The results are shown in FIG.

According to the results shown in FIG. 24, similar to the results shown in FIGS. That is, it turns out that the fluorescence light source device 1 of 1st embodiment has the extraction efficiency of the fluorescence L10 improved.

(Verification 4)
A simulation was performed assuming the fluorescence light source device 1 of the second embodiment. That is, the fluorescent light source device 1 including the mirror member 40 was used as the simulation target. More specifically, the fluorescence light source device 1 provided with the mirror members 40 (40a, 40b, 40c, 40d) on the four sides of the outer periphery of the phosphor 10 was simulated. In addition, in this verification, the fluorescent light source device 1 including the phosphor 10 having the curved surface 15 instead of the inclined surface 13 was subjected to the simulation.

<Setting conditions>
In the fluorescence light source device 1 used for the simulation, as shown in FIG. 25, the length w1 in the X direction of the phosphor 10 provided in the fluorescence light source device 1 is 10 mm, and the shape related to the second end 12 side was 1 mm x 1 mm. Also, the distance w2 between the X coordinate x1, which is the starting point of the curved surface 15 of the phosphor 10 in the X direction, and the X coordinate x2 of the first end portion 11 was set to 6.67 mm. That is, the distance between the coordinates x1 and x2 was set to 2/3 of the distance between the coordinates x0 and x2 in the X direction.

<Results>
Under the above setting conditions, the extraction efficiency of the fluorescence L10 was evaluated when the length t in the Y direction of the phosphor 10 at the first end 11 was varied from 0 mm to 1 mm. The results are shown in FIG.

According to the results shown in FIG. 26, similarly to the results shown in FIG. It can be seen that the fluorescence light source device 1 of the embodiment has a higher extraction efficiency of the fluorescence L10.

[Another embodiment]
Another embodiment will be described below.

<1> The fluorescence light source device 1 of the first embodiment may further include the mirror member 40 described above in the second embodiment.

<2> Like the fluorescence light source device 2 shown in FIG. 27, in addition to the fluorescence light source device 1 described above in the first embodiment or the second embodiment, a condensing optical system 71 and a light guide member 72 are provided. I don't mind. The fluorescence L10 emitted from the fluorescence light source device 1 is condensed on the incident surface 72a of the light guide member 72 by the condensing optical system 71, and is incident on the subsequent optical system (not shown) from the light guide member 72. FIG. It should be noted that the condensing optical system 71 is composed of, for example, a condensing lens such as a convex lens. The light guide member 72 is composed of an optical member such as a rod integrator (also called a “light pipe”).

According to the fluorescence light source device 2, the fluorescence L10 with high luminance can be incident on the incident surface 72a of the light guide member 72. As shown in FIG.

Further, like the fluorescence light source device 2 shown in FIG. 28 , it further includes another light source 73 that emits light L73 having a wavelength different from that of the fluorescence L10. The combined light may be condensed on the light guide member 72 . In the example shown in FIG. 28, the fluorescence light source device 2 includes refractive optics (74, 75) and a dichroic mirror 76 that transmits fluorescence L10 and reflects light L73. Fluorescence L10 emitted from the fluorescence light source device 1 and converted into substantially parallel light through the refractive optical system 74 is transmitted through the dichroic mirror 76 and guided to the condensing optical system 71 . Light L73 emitted from the light source 73 and converted into substantially parallel light through the refractive optical system 74 is reflected by the dichroic mirror 76 and guided to the condensing optical system 71 .

For example, by emitting blue light L73 from the light source 73 and emitting yellow fluorescence L10 from the fluorescence light source device 1, white light with high luminance can be incident on the light guide member 72. Such white light can be used as light source light for projectors and the like.

In FIG. 28, instead of the dichroic mirror 76, a dichroic mirror (not shown) that reflects the fluorescence L10 and transmits the light L73 may be provided.

<3> In each of the above embodiments, the excitation light source 30 is described as being composed of an LED element, but may be composed of a laser diode (LD) element.

1: Fluorescence Light Source Device 2: Fluorescence Light Source Device 10: Phosphor 11: First End of Phosphor 12: Second End of Phosphor 13: Inclined Surface of Phosphor 14: Side of Phosphor 15: Phosphor Curved surface 20: Glass member 30: Excitation light source 40: Mirror member 40a, 40b, 40c, 40d: Mirror member 71: Condensing optical system 72: Light guide member 72a: Entrance surface of light guide member 73: Light source 74, 75: Refraction Optical system 76: dichroic mirror 100: conventional phosphor 101: exit surface of phosphor 110: collector 111: side surface of collector 112: exit surface of collector L10: fluorescence L10a, L10b, L10c: fluorescence L30 : excitation light L73: light L100: fluorescence

Claims (6)

The first direction is the longitudinal direction, and the width in the second direction orthogonal to the first direction is substantially the same as the width approaches the first end, which is one end in the first direction, from a predetermined location. a phosphor that has a shape including an inclined surface or curved surface that decreases to
an excitation light source that emits excitation light of the first wavelength, arranged along the first direction on the outer side of the phosphor in the second direction;
It is made of a material that exhibits transparency to the fluorescence and has a refractive index value that is higher than the refractive index of air and lower than the refractive index of the phosphor. A fluorescent light source device, comprising: a glass member arranged with its surfaces joined to each other. characterized by comprising a mirror member exhibiting reflectivity with respect to the fluorescence, arranged at an outer position in the second direction of the region in which the inclined surface or the curved surface of the phosphor is formed. Item 1. The fluorescence light source device according to item 1. The mirror member is also arranged at a position outside the inclined surface or the curved surface of the phosphor in a third direction perpendicular to the first direction and the second direction. 3. The fluorescence light source device according to claim 2 , which exhibits a U-shape or a square shape when folded. The length of the width in the second direction in the region where the inclined surface or the curved surface of the phosphor is not formed is the second direction in the region where the inclined surface or the curved surface of the phosphor is formed. and the width of the glass member in the second direction. The phosphor has a second end that is an end opposite to the first end with respect to the first direction when viewed from a third direction orthogonal to the first direction and the second direction to said predetermined point shows a rectangular shape, and the area from said predetermined point to said first end shows a trapezoidal shape, a triangular shape, a circular arc shape, or an elliptical arc shape. 5. The fluorescence light source device according to any one of 1 to 4 . a refractive optical system arranged at a position outside the first end of the phosphor and condensing the fluorescence emitted in the first direction from at least the first end of the phosphor;
The fluorescence light source device according to any one of claims 1 to 5 , further comprising a post-stage optical system into which the fluorescence condensed by the refractive optical system is incident.

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