Light source device

Abstract

This light source device is provided with: a reflection part (30a) that reflects a laser beam bundle B having a plurality of laser beams; a phosphor part (40); and a light-condensing optical system (50) that is disposed between the reflection part (30a) and the phosphor part (40), allows the laser beam bundle (B) reflected by the reflection part (30a) to pass therethrough in a first direction, and directs the laser beam bundle (B) toward the phosphor part (40). The light-condensing optical system (50) allows fluorescence emitted radially from the phosphor part (40) to pass therethrough in a second direction opposite to the first direction and emits the fluorescence. When viewed from a fluorescence emission direction which is a direction in which the light-condensing optical system (50) emits the fluorescence, a range in which the reflection part (30a) is provided is 1 / 3 or less with respect to an area of a lens surface (51a) of the light-condensing optical system (50) through which the fluorescence last passes in the second direction.

Description

Light source device

[0001] The present invention relates to a light source device.

[0002] A light source device that condenses a plurality of laser beams on a phosphor and uses fluorescence excited from the phosphor is known. For example, refer to Patent Document 1.

[0003] Japanese Patent Application Laid-Open No. 2012-027052

[0004] In such a light source device, there is a demand for a light source device that can further increase the amount of light and can be stably used while increasing the amount of light.

[0005] The light source device according to one aspect of the present invention includes a reflection unit that reflects a laser beam having a plurality of laser beams, a phosphor unit, and a condensing optical system disposed between the reflection unit and the phosphor unit, and passing the laser beam reflected by the reflection unit in a first direction toward the phosphor unit. The condensing optical system passes fluorescence radially emitted from the phosphor unit in a second direction opposite to the first direction and emits the fluorescence. When viewed from the fluorescence emission direction, which is the direction in which the condensing optical system emits the fluorescence, the range where the reflection unit is provided is 1 / 3 or less with respect to the area of the lens surface where the fluorescence finally passes in the second direction in the condensing optical system.

[0006] This is a schematic perspective view of a light source device according to one embodiment. This is a perspective view showing the schematic configuration of the reflective unit of the light source device according to this embodiment. This is a perspective view showing the configuration of the reflective unit of the light source device according to this embodiment. This is a schematic side view showing a cross-section of a part of the light source device according to this embodiment. This is a cross-sectional view of the reflective unit of the light source device according to this embodiment. This is a cross-sectional view showing the configuration of the reflective unit of the light source device according to this embodiment. This is a diagram showing an example of the laser beam field pattern of the light source device according to this embodiment. This is a cross-sectional view of the reflective unit of the light source device according to the first modified example of this embodiment. This is a cross-sectional view of the reflective unit of the light source device according to the second modified example of this embodiment. This is a schematic side view showing a cross-section of a part of the light source device according to the third modified example of this embodiment. This is a schematic side view showing a cross-section of a part of the light source device according to the fourth modified example of this embodiment. This is a cross-sectional view of a part of the light source device according to the fifth modified example of this embodiment. This is a schematic side view showing a cross-section of a part of the light source device according to the sixth modified example of this embodiment. This is a schematic side view showing a cross-section of a part of the light source device according to the seventh modified example of this embodiment. This is a schematic diagram showing a method for measuring light intensity. This is a graph showing an example of light intensity measurement results.

[0007] A light source device 1 of one embodiment will be described below with reference to the figures. As shown in Figure 1, the light source device 1 includes a first light source 10 that emits a plurality of laser beams L, and the plurality of laser beams L are substantially parallel to each other. As an example, as shown in Figure 1, the first light source 10 has, for example, a plurality of semiconductor lasers 11 such as laser diodes arranged in the X-axis direction and the Y-axis direction. In this embodiment, the plurality of semiconductor lasers 11 are of the same type, but they may be of different types. The wavelength of the laser beams L emitted from the semiconductor lasers 11 in this embodiment is 465 nm or less. Other wavelengths may be used.

[0008] Multiple semiconductor lasers 11 are mounted on a substrate (not shown), and the substrate is cooled by a cooling device (not shown). A water-cooled cooling device or a cooling device having both water and air cooling can be used. Other types of cooling devices may also be employed. In this embodiment, the multiple semiconductor lasers 11 are arranged in the X-axis and Y-axis directions, but the multiple semiconductor lasers 11 may be arranged in other directions as long as the first light source 10 can emit multiple laser beams L that are substantially parallel to each other.

[0009] In this embodiment, a second light source 15 is provided that emits multiple laser beams L, and adjacent laser beams L are substantially parallel to each other. As an example, as shown in Figure 1, the second light source 15 has, for example, multiple semiconductor lasers 11 arranged in the X-axis and Y-axis directions. In the first light source 10 and the second light source 15, the state in which adjacent laser beams L are substantially parallel to each other is a state in which adjacent laser beams L form an angle of 3° or less with respect to each other, more preferably an angle of 2° or less, and even more preferably an angle of 1° or less. If the effects described later are achieved, it is also possible for adjacent laser beams L to form an angle of 5° or less or a greater angle with respect to each other, but as shown in Figure 1, the smaller the angle formed by adjacent laser beams L and the closer they are to parallel, the more reliably the configuration and effects described later are realized. In the embodiments described below, unless otherwise specified, when a laser beam L (the straight line of the optical axis) and a certain straight line are substantially parallel, or when two laser beams L (the straight lines of the optical axes) are substantially parallel, the straight lines form the angle described above.

[0010] Multiple semiconductor lasers 11 are mounted on a substrate (not shown), and the substrate is cooled by the cooling device. In this embodiment, the multiple semiconductor lasers 11 are arranged in the X-axis and Y-axis directions, but the multiple semiconductor lasers 11 may be arranged in other directions as long as the second light source 15 can emit multiple laser beams L that are substantially parallel to each other. The multiple semiconductor lasers 11 of the second light source 15 may be arranged to emit multiple laser beams L in a direction substantially parallel to the light supply axis LA described below. Alternatively, the first light source 10 and the second light source 15 may be light sources that use optical elements to make the multiple laser beams L from the multiple semiconductor lasers 11 substantially parallel to each other.

[0011] In this embodiment, multiple laser beams L from the first light source 10 are each reflected by the first light source reflector 14 in a direction substantially parallel to the light supply axis LA or the optical axis of the positive lens portion 21 described later. The substantially parallel direction is a direction that forms an angle of 3° or less with respect to the straight line of the light supply axis LA or the optical axis, and more preferably an angle of 2° or less. If the effects described later are achieved, the angle may be 5° or less or greater, but as shown in Figure 1, a smaller angle that is closer to parallel ensures that the configuration and effects described later are reliably achieved.

[0012] In this embodiment, the light supply axis LA is parallel to the X-axis, and the first light source reflector 14 is an optical system that combines the laser light L from the first light source 10 and the second light source 15. The light supply axis LA can also be described as the optical axes of a plurality of substantially parallel laser beams L reflected by the first light source reflector 14.

[0013] In this embodiment, the second light source 15 has a second light source reflector 17. The multiple laser beams L of the second light source 15 are each reflected by the second light source reflector 17 in a direction substantially parallel to the light supply axis LA. In other words, the second light source 15 having the second light source reflector 17 can also be described as a light source that emits multiple laser beams L in a direction substantially parallel to the light supply axis LA.

[0014] Multiple laser beams L reflected by the second light source reflector 17 pass through the transmission region 14b of the first light source reflector 14. In other words, the first light source reflector 14 is provided with a reflection region 14a corresponding to the positions of the multiple laser beams L from the first light source 10, and a transmission region 14b in the remaining portion. The transmission region 14b can also be described as the region where the reflection region 14a is not provided.

[0015] In one example, the first light source reflector 14 is made of a glass plate, with a reflective film such as a dielectric multilayer film formed in each reflective region 14a, and no reflective film formed in the transmissive region 14b. The transmissive region 14b may be a plurality of slits, holes, elongated holes, notches, etc. formed in the glass plate.

[0016] With the above configuration, multiple laser beams L reflected by the first light source reflector 14 and multiple laser beams L from the second light source reflector 17 are combined. In this embodiment, the multiple laser beams L from the second light source 15 having the second light source reflector 17 are substantially parallel to the multiple laser beams L reflected by the first light source reflector 14 and are offset in a direction perpendicular to the light supply axis LA.

[0017] The light source device 1 includes a density-changing optical system 20. The density-changing optical system 20 is an optical system for increasing the number (density) of laser beams L in a plane (Y-Z plane in this embodiment) perpendicular to the optical axis of the laser beam L. In this embodiment, the density-changing optical system 20 includes, as an example, a positive lens section 21 which is a single convex lens, and a negative lens section 22 which includes, as an example, a single unidirectional concave lens 22a and a single concave lens 22b. In this embodiment, the positive lens is a lens with positive power, and the negative lens is a lens with negative power.

[0018] In this embodiment, the unidirectional concave lens 22a, as shown in Figures 1, 4, and 5, is a lens having a concave surface with curvature mainly in the Y-axis direction, and is positioned with the purpose and / or function of slightly spreading each laser beam in the Y-axis direction. This is particularly useful when the cross-section of each laser beam reaching the phosphor 41 is long in the X-axis direction, as shown in Figure 7. The cross-section may be referred to as a field pattern, etc.

[0019] In Figure 7, the field pattern of the laser beam L without the unidirectional concave lens 22a is shown by a dashed line and hatching. Note that in Figure 7, the field patterns of the four laser beams L aligned in the Y-axis direction within the unidirectional concave lens 22a are shown in a schematic diagram for the purpose of the explanation below, and the size and shape of each field pattern in Figure 7 may differ from the actual ones. The field pattern of the laser beam L from the semiconductor laser 11 may be elongated in one direction and elliptical, but the unidirectional concave lens 22a is positioned to widen the field pattern in the shorter direction, as shown by the solid ellipse in Figure 7. For this reason, if the field pattern of each laser beam L is elongated in the Y-axis direction, unlike in Figure 7, the unidirectional concave lens 22a becomes a lens with a concave surface that has curvature mainly in the X-axis direction, and can be positioned with the purpose and / or function of slightly widening each laser beam L in the X-axis direction.

[0020] As described above, multiple parallel laser beams L traveling in the direction of the light supply axis LA (X-axis direction) are bent in the focusing direction toward the optical axis of the positive lens section 21 by the positive lens section 21, and then bent in a direction substantially parallel to the optical axis of the negative lens section 22. In this embodiment, the optical axis of the negative lens section 22 is parallel to the X-axis. As a result, the multiple laser beams L that have passed through the density changing optical system 20 are closer to each other than before they entered the density changing optical system 20. In this embodiment, the multiple laser beams L that have passed through the density changing optical system 20 are multiple laser beams L that are substantially parallel to each other and are referred to as the laser beam B. In some cases, the density changing optical system 20 may use the configuration disclosed in Japanese Patent Application Publication No. 2-60179 (a configuration having multiple mirrors) to bring the multiple laser beams L closer to each other.

[0021] In this embodiment, the laser beam B travels in a direction along the X-axis (laser light supply direction) and is incident on the reflecting member 30. The reflecting member 30 is a known dichroic mirror or the like, and has a reflective portion 30a (reflective surface) whose transmittance changes according to the wavelength of light. In this embodiment, a dichroic mirror is used as the reflecting member 30, in which a reflective film such as a dielectric multilayer film is formed as the reflective portion 30a on the surface of a glass plate 31. In this embodiment, the reflecting member 30 reflects the laser beam B in a direction substantially aligned with the Z-axis. In this embodiment, the direction substantially aligned with the Z-axis is the direction substantially aligned with the fluorescence emission axis, which will be described later. The Z-axis is perpendicular to the X-axis and Y-axis, and the Y-axis is perpendicular to the X-axis.

[0022] In one example, the laser beam B consists of adjacent laser beams L that are substantially parallel to each other. This configuration ensures that the configuration and effects described later can be reliably achieved. In this embodiment, the state in which the laser beam B is substantially aligned with the axis is a state in which the angle between the optical axis of the laser beam B and the straight line of the axis is 3° or less, more preferably 2° or less, and even more preferably 1° or less. The angle may also be 5° or less or greater if the effects described later are achieved.

[0023] In this embodiment, the density-changing optical system 20 has a unidirectional concave lens 22a. Therefore, in this embodiment, when viewed from the Z-axis direction, at least a portion of the multiple laser beams L in the laser beam B are not parallel, but when viewed from the Y-axis direction, all or many of the multiple laser beams L in the laser beam B are configured to be parallel. The many portion is 85% or more, more preferably 90% or more.

[0024] The light source device 1 includes a phosphor section 40. The phosphor section 40 has a phosphor 41 and a focusing lens 42 positioned between the phosphor 41 and the reflective member 30 in the Z-axis direction.

[0025] The light source device 1 includes a focusing optical system 50 between the phosphor section 40 and the reflective member 30. In this embodiment, the focusing optical system 50 has, as an example, a positive lens 51, which is a convex lens. In this embodiment, the optical axis of the focusing optical system 50 and the optical axis of the focusing lens 42 of the phosphor section 40 extend in the Z-axis direction and are arranged coaxially. In this embodiment, the direction of the fluorescence emission axis coincides with the direction of the Z-axis, but the direction of the fluorescence emission axis may be oblique or perpendicular to the direction of the Z-axis. Furthermore, as long as fluorescence from the phosphor 41 can be input to the light input section as described later, the optical axis of the focusing optical system 50 and the optical axis of the focusing lens 42 of the phosphor section 40 do not need to be arranged coaxially.

[0026] The focusing optical system 50 focuses the laser beam B entering from the side of the reflecting section 30a onto the phosphor section 40, and the laser beam B is then focused onto the phosphor 41 by the focusing lens 42 of the phosphor section 40. Therefore, the laser beam B reflected by the reflecting section 30a passes through the focusing optical system 50 in the first direction and is focused onto the phosphor 41. In other words, the laser beam B is directed towards the phosphor 41 by the focusing optical system 50.

[0027] The laser beam B causes fluorescence to be emitted from the phosphor 41, and the emitted fluorescence is emitted radially from the focusing lens 42. The effects of this embodiment are achieved even if the emission is not perfectly uniform around the entire circumference. Furthermore, it is natural that there will be variations in light intensity, such as increased intensity in the incident direction of the laser beam B or near the center of the focusing lens 42. The fluorescence emitted from the focusing lens 42 passes through the focusing optical system 50 in a second direction opposite to the first direction (including cases where it is not straight along the optical axis), and the fluorescence that has passed through the focusing optical system 50 travels along the fluorescence emission axis. In this embodiment, the fluorescence that has passed through the focusing optical system 50 becomes approximately parallel light, but a configuration in which the fluorescence that has passed through the focusing optical system 50 gradually spreads out or gradually converges is also possible. In the light source device 1 of this embodiment, the fluorescence that has passed through the focusing optical system 50 passes through a focusing optical system consisting of a focusing lens 70, and is then supplied to the end of a light guide such as an optical fiber, or to a predetermined target. Alternatively, the fluorescence that has passed through the focusing optical system 50 may be supplied to a light guide, a predetermined target, etc., after passing through other optical systems.

[0028] In this embodiment, part or all of the reflective member 30 is positioned in the area where fluorescence that has passed through the focusing optical system 50 travels. In this embodiment, the area is the area of ​​the cross-section perpendicular to the fluorescence emission axis EA (Figure 4) of the fluorescence that has passed through the focusing optical system 50. When laser light L is emitted from the first light source 10 and the second light source 15 at a measurable intensity such as the rated output, 1 / 10, 1 / 50, or 1 / 100 of the rated output or maximum output, the area can be identified by considering that there is a range outside the area where the illuminance is 3 / 10 or less of the light intensity near the center of the area. Instead of 3 / 10, values ​​such as 2 / 10, 1 / 10, or smaller values ​​may be used, which makes the difference in light intensity inside and outside the range clearer.

[0029] As shown in Figure 5, in the fluorescence emission direction, which is along the fluorescence emission axis EA, the reflective portion 30a is positioned at a predetermined position or within a predetermined range in Figure 4. The predetermined position in Figure 4 is approximately the center of the reflective portion 30a, while examples of the predetermined range include a range of several millimeters or a range of more than ten millimeters in the fluorescence emission direction. In this embodiment, part or all of the reflective portion 30a is positioned within the area at the predetermined position or within the predetermined range. The area of ​​the reflective portion 30a positioned within the area as viewed from the fluorescence emission direction (reflective portion range) is 1 / 3 or less of the area of ​​the area corresponding to the predetermined position or range. More preferably, the reflective portion range is 1 / 4 of the area, and even more preferably 1 / 6 or less or 1 / 8 or less. The reflective portion range is the area of ​​the reflective portion 30a positioned within the range where strong fluorescence emitted from the convex curved surface 51a can hit, and weak light such as leak light or light that easily becomes stray light is not included in the strong fluorescence. Examples of stray light include fluorescence other than that which travels in a direction that is effectively utilized through the focusing lens 70. For this reason, for example, the reflective area is the area of ​​the reflective section 30a that is positioned in a range where strong fluorescence that is effectively utilized through the focusing lens 70 can strike.

[0030] In one example, the area of ​​the area is measured or calculated at the predetermined position, the predetermined range, or a position shifted by several millimeters from the predetermined range in the direction of fluorescence emission. The area of ​​the area is measured or calculated at a position shifted by, for example, 5 cm or less from the predetermined range in the direction of fluorescence emission, if the optical system is set up so that the fluorescence that passes through the focusing optical system 50 becomes substantially parallel light. Alternatively, if the area of ​​the cross-section of the fluorescence that passes through the focusing optical system 50 perpendicular to the direction of fluorescence emission decreases or increases by a predetermined ratio toward the focusing lens 70 (the fluorescence becomes thinner or thicker), the measurement can be performed at a position shifted by, for example, several centimeters or tens of centimeters or less from the predetermined range in the direction of fluorescence emission, and the area of ​​the area in the predetermined range can be calculated considering the predetermined ratio. The focusing lens 70 may be removed for the measurement and / or calculation. In some cases, the fluorescence can be considered to be present on the entire inner surface of the inner circumferential surface between the focusing lens 70 and the convex curved surface 51a, which is the inner circumferential surface of the support member 60 in the direction from which the fluorescence is emitted from the convex curved surface 51a. Alternatively, fluorescence should be present at least on the inner side of the inner circumferential surface. In these cases, the area of ​​the cross-section of the inner circumferential surface perpendicular to the direction of fluorescence emission may be considered to be the area of ​​the region.

[0031] As an example of the measurement described above, the measurement shown in Figure 15 is possible. In the measurement shown in Figure 15, one end face of the optical fiber receives fluorescence, and a cylindrical light-shielding member with a 1 mm diameter hole is attached to one end face of the optical fiber so that the light-receiving end face has a diameter of 1 mm. The light emitted from the other end face of the optical fiber is irradiated onto a light intensity detection means having a light intensity detection element such as a photoresistor or photodiode. Examples of light intensity detection means include a known illuminometer, such an illuminometer, or one with a similar configuration. It is also possible to perform the same measurement using a pinhole or the like instead of an optical fiber, and other methods can also be used. In this embodiment, the direction in which the optical fiber extends on the light-receiving end face side is approximately parallel to the fluorescence emission direction. Furthermore, while moving the light-receiving end face in the radial direction of the area as shown in Figure 15, the amount of light (illuminance) received by the light intensity detection element at each position is measured. The measurement results are shown in Figure 16, for example. In Figure 16, the range from -8.3 mm to +8.3 mm is the range where the light intensity measured is more than 3 / 10 of the light intensity near the center of the area, and the area outside of this range is the range where the light intensity is 3 / 10 or less of the light intensity near the center of the area. In this embodiment, since the cross-section of the area is circular due to the positive lens 51, the area (area of ​​the cross-section perpendicular to the fluorescence emission axis EA) is a circle with a diameter of 16.6 mm centered on the fluorescence emission axis EA. It is also possible to measure the area using an area sensor. In other words, it is sufficient to measure the distribution of the light intensity of the fluorescence emitted from the convex curved surface 50a on a plane perpendicular to the fluorescence emission axis EA. The above calculation can be performed using simulation or the like.

[0032] In one example, the predetermined position is any intermediate position between one end and the other end of the reflective portion 30a in the fluorescence emission direction. In another example, as shown in Figure 4, the predetermined position is the central position between one end and the other end of the reflective portion 30a in the fluorescence emission direction.

[0033] In Figure 5, the area at the predetermined position is enclosed by a dashed circle and is hatched. The area of ​​the reflective portion 30a, shown by a dashed rectangle in Figure 5, as viewed from the direction of fluorescence emission (area in Figure 5) is 1 / 6 of the area of ​​this region.

[0034] In this embodiment, as shown in Figure 5, in the predetermined position or range, the dimension XL2 of the reflective area in the X-axis direction is 1 / 2 or less of the dimension XL1 of the area in the X-axis direction, more preferably 1 / 3 or less. Also, in the predetermined position or range, the dimension YL2 of the reflective area in the Y-axis direction is 2 / 3 or less of the dimension YL1 of the area in the Y-axis direction, more preferably 3 / 5 or less. Therefore, as shown in Figure 8, other reflective areas 30a can be positioned at locations offset around the fluorescence emission axis EA, and laser beams B from other light sources can be incident on the other reflective areas 30a. This makes it possible to increase the power of the laser beam B introduced into the phosphor section 40 as needed. The above dimensions XL2 and YL2 do not limit the present invention, and dimensions XL2 and YL2 may be other than those described above as long as similar effects can be achieved.

[0035] Furthermore, it is possible to make the positions of the multiple reflective sections 30a in the Z direction different from each other. For example, it is possible to support the multiple reflective sections 30a with the support member 60 described later so that their positions in the Z direction are different from each other. It is also possible to reduce the dimension YL2 of the reflective section 30a in the circumferential direction around the fluorescence emission axis EA. It is also possible to reduce the circumferential dimension YL2 of the reflective section 30a as it approaches the fluorescence emission axis EA. Using these configurations, or even without using these configurations, this embodiment can arrange any number of reflective sections 30a (3 or more) around the fluorescence emission axis EA so that their positions are different from each other.

[0036] When the maximum outer diameter of the focusing optical system 50 is set with consideration for space saving, the area of ​​the aforementioned area is often 1 / 3 or 1 / 4 or less of the area of ​​the largest lens of the focusing optical system 50 when viewed from the direction of fluorescence emission. For this reason, the area of ​​the reflective portion 30a when viewed from the direction of fluorescence emission can also be said to be 1 / 3 or 1 / 4 or less of the area of ​​the largest lens. Furthermore, in this embodiment, the largest lens can also be said to be the convex curved surface 51a through which the fluorescence passes last in the second direction.

[0037] Furthermore, it is also possible to design the convex curved surface 51a (the lens surface of the positive lens 51, which is the final positive power lens) that the fluorescence of the focusing optical system 50 passes through last, as viewed from the direction of fluorescence emission, to coincide with the area. In Figure 4, the area of ​​the convex curved surface 51a is smaller than the area, but in some cases, such as as shown in Figure 10, the area of ​​the convex curved surface 51a may coincide with the area. In the example of Figure 10, the fluorescence emitted from the convex curved surface 51a is approximately parallel light, and therefore the area at the predetermined position or range away from the convex curved surface 51a coincides with the area of ​​the convex curved surface 51a.

[0038] Furthermore, as shown in Figure 11, the outer periphery of the convex curved surface 51a of the focusing optical system 50 may be shielded by the lens retaining portion 62a of the second member 62, which will be described later. In this case, in this embodiment, the area of ​​the convex curved surface 51a that is not shielded and / or the area of ​​the convex curved surface 51a that is substantially used for fluorescence emission, as viewed from the fluorescence emission direction, can be said to be the area of ​​the convex curved surface 51a.

[0039] It is common practice to design the system so that the fluorescence after passing through the convex curved surface 51a is approximately parallel light, slightly wider light, or slightly more focused light. Furthermore, when the fluorescence after passing through the convex curved surface 51a is either slightly wider or slightly more focused light, the distance between the reflector 30a and the convex curved surface 51a is often set to a small value to avoid complicating the optical path configuration.

[0040] Considering the various circumstances described above, the effects described above and below are achieved when the area of ​​the reflective portion 30a, as viewed from the direction of fluorescence emission, is 1 / 3 or less of the area of ​​the convex curved surface 51a.

[0041] The reflective portion 30a is configured to reflect light of the wavelength of the laser beam B but not the fluorescence from the phosphor 41. However, it is difficult to form the reflective portion 30a so that it transmits all fluorescence without reflecting any of it, and the glass surface on which the reflective portion 30a is formed also reflects some fluorescence. For this reason, the above configuration can be said to be useful in reducing fluorescence loss.

[0042] Here, in the present embodiment, the laser beam B is incident only on a part of the circumferential direction of the condensing optical system 50, and the laser beam B is condensed on the phosphor 41. However, the phosphor 41 emits fluorescence in a radiation direction including directions other than the incident direction of the laser light L. This configuration is useful for reducing the loss of the fluorescence.

[0043] In the present embodiment, the reflecting portion 30a is positioned with respect to the phosphor 41 by the support member 60. The support member 60 of the present embodiment is fixed to the phosphor mounting surface on which the substrate of the phosphor 41 is mounted, but the support member 60 may be fixed to other members. The phosphor mounting surface may be the surface of the substrate on which the phosphor 41 is mounted, the surface of a cooling member for cooling the substrate of the phosphor 41, or the like. The cooling member is a metal member or the like that constitutes a part of a water-cooled cooling device.

[0044] As shown in FIG. 12, there may be a case where the phosphor 41 is provided in a donut shape on the disk 43 and the disk 43 is rotated by the motor 44. Such a configuration can be adopted from the viewpoint of preventing early damage of the phosphor 41. There may be cases where the phosphor 41 is provided in other modes. Even in these cases, the support member 60 positions the reflecting portion 30a with respect to the phosphor 41.

[0045] As shown in FIG. 6, the support member 60 of the present embodiment has a first opening 60a that opens in the fluorescence emission direction at a position farther from the phosphor 41 than the reflecting portion 30a in the fluorescence emission direction, and at least one second opening 60b that is disposed at a position closer to the phosphor 41 than the first opening 60a in the fluorescence emission direction and opens in a direction intersecting the fluorescence emission direction. The intersecting direction is the X-axis direction in the present embodiment.

[0046] As in the light ray locus of a part of the laser light L shown in FIG. 4, in the present embodiment, a plurality of laser lights L that have passed through the positive lens portion 21 travel toward the second opening 60b. Further, the negative lens portion 22 is fixed to the support member 60 so that the light traveling toward the second opening 60b or the light that has entered the second opening 60b becomes the laser beam B.

[0047] In this embodiment, the condenser optical system 50 is positioned by fitting it into the support member 60 or the like and fixed by known fixing means. The condenser optical system 50 may be fixed to another member, and the other member may be positioned by fitting it into the support member 60 or the like and fixed by known fixing means. The positioning may be performed by other known methods other than fitting.

[0048] The reflecting portion 30a is fixed to the support member 60 such that the laser beam B from the negative lens portion 22 enters the condenser optical system 50 as described above. As an example, in this embodiment, a glass plate 31 provided with the reflecting portion 30a is fixed to the support member 60. Condensing the laser beam B on the phosphor 41 as closely as possible to the design aim contributes to stabilizing the amount of fluorescence output, appropriately setting the fluorescence output direction through the condenser optical system 50, and the like. Therefore, the configuration in which each element is positioned by the support member 60 as described above is useful.

[0049] The support member 60 is provided with a support surface 63 which is an inclined surface for fixing the glass plate 31 provided with the reflecting portion 30a. In this embodiment, as shown in FIG. 2, a plurality of support surfaces 63 are provided on the second member 62 of the support member 60, and the glass plate 31 is fixed to a part or all of them. The support surface 63 may be provided on the first member 61 of the support member 60.

[0050] In this embodiment, the glass plate 31 which is a flat plate is fixed to the support member 60 so as to be in surface contact with the support surface 63, whereby the reflecting portion 30a is also arranged at an inclination angle along the support surface 63. The inclination angle is a predetermined angle (45°) with respect to the X-axis direction (laser light supply direction) and the Z-axis direction (fluorescence emission direction) such that the reflecting portion 30a deflects the laser beam B traveling in the X-axis direction as described above in the Z-axis direction. Thus, the glass plate 31 provided with the reflecting portion 30a is surely fixed at the target angle using the support surface 63 which is an inclined surface, and the angle of the reflecting portion 30a is difficult to shift due to vibrations applied to the support member 60. The said configuration is useful in realizing stabilizing the amount of fluorescence output, appropriately setting the fluorescence output direction through the condenser optical system 50, and the like.

[0051] As shown in Figure 6 and other figures, the support member 60 of this embodiment includes a cylindrical first member 61 having a first opening 60a, and a second member 62 positioned on the phosphor 41 side of the first member 61 in the fluorescence emission direction. In one example, the first member 61 and the second member 62 are made of metal, and in this embodiment, the support surface 63 is the surface of the second member 62 facing the first member 61. As shown in Figures 2-3, the support surface 63 is formed radially inward on one axial end face of the cylindrical second member 62, and as shown in Figures 3-4, a part of the surface 61a of one axial end face of the first member 61 faces the support surface 63. In this embodiment, a reflective portion 30a is provided on one end of the glass plate 31, and the other end (plate-like portion) of the glass plate 31 is in surface contact with the support surface 63. The other end of the glass plate 31 may be sandwiched directly or via another member by the support surface 63 and a part of the surface 61a. The other member may be a flexible member such as rubber. In this embodiment, as shown in Figure 2, the Y-axis dimension of the other end of the glass plate 31 is larger than the Y-axis dimension of the one end of the glass plate 31. In this embodiment, the reflective member 30 provided with the reflective portion 30a is cantilevered so that the end on which the reflective portion 30a is provided is the unsupported side. This configuration is useful for reducing the size of the reflective member 30 and its support structure, which are placed in the area through which the fluorescence passes.

[0052] In this embodiment, the reflective area is less than 1 / 3 of the area of ​​the convex curved surface 51a and the area where the fluorescence propagates, as described above. This configuration is useful for reducing fluorescence loss. In addition, in this embodiment, multiple reflective sections 30a can be arranged around the fluorescence emission axis EA at different positions from each other. This configuration enables improved fluorescence output while saving space.

[0053] Furthermore, in this embodiment, the reflective portion 30a is positioned so as not to be at the center of the convex curved surface (lens surface) 51a when viewed from the direction of fluorescence emission. Therefore, in this embodiment, fluorescence near the fluorescence emission axis EA emitted from the center of the phosphor 41 is not obstructed by the reflective portion 30a. This configuration is useful for emitting strong fluorescence from the light source device 1.

[0054] As shown in Figure 9, a laser beam capturing section 32 may be provided in the area opposite to the reflecting section 30a, with the fluorescence emission axis EA in between. In this embodiment, the laser beam capturing section 32 is the same reflective film as the reflecting section 30a, and the laser beam capturing section 32 is formed on the surface of a glass plate 34 fixed to the support surface 63. The laser beam capturing section 32 is formed to reflect light of the wavelength of the laser beam B and transmit fluorescence, similar to the reflecting section 30a.

[0055] A considerable portion of the laser beam B incident on the phosphor 41 via the focusing optical system 50 from the reflecting section 30a is used to excite fluorescence, but the remaining portion is reflected by the base surface 45, which is made of metal or the like and has the phosphor 41 on its surface. A portion of the reflected laser beam B tends to travel in the area opposite to the reflecting section 30a, with the fluorescence emission axis EA in between. The presence of the laser beam capturing section 32 makes it possible to efficiently reduce or eliminate the amount of light of the wavelength component of the laser beam B output from the light source device 1. Note that, as described above, when multiple reflecting sections 30a are arranged around the fluorescence emission axis EA at different positions from each other, one of the reflecting sections 30a also functions as the laser beam capturing section 32.

[0056] Furthermore, as shown in the modified example in Figure 13, it is also possible to provide a hole 51b in the positive lens 51 of the focusing optical system 50. The focusing optical system 50, through its hole 51b, allows the laser beam B from the reflecting section 30a to pass through the focusing optical system 50 in a first direction and be directed toward the phosphor 41. The direction of passage of this laser beam B does not have to coincide with the optical axis direction of the focusing optical system 50. In addition, even in the above embodiment, the direction of passage of the laser beam B may not coincide with the optical axis direction of the focusing optical system 50.

[0057] The laser beam B reflected by the reflective section 30a enters the hole 51b through one opening and exits through the other opening. In Figure 13, the hole 51b opens on one and the other surfaces of the positive lens 51 in the fluorescence emission direction.

[0058] In the modified example shown in Figure 13, the focusing lens 42 is also provided with a hole 42a, and the hole 51b opens to one lens surface and the other lens surface of the positive lens 51 in the fluorescence emission direction. The laser beam B that exits from the other opening of hole 51b enters hole 42a through one opening of hole 42a and exits from the other opening of hole 42a. The laser beam B that exits from the other opening of hole 42a strikes the phosphor 41. When the laser beam B strikes the phosphor 41, fluorescence is emitted radially from the phosphor 41, similar to the embodiment described above, and this fluorescence passes through the focusing lens 42 and the focusing optical system 50 in the second direction.

[0059] In this modified example, as in the embodiment described above, the reflective area is 1 / 3 or less of the area of ​​the convex curved surface 51a and the area where fluorescence progresses. Therefore, this modified example can also achieve the same effects as the embodiment described above.

[0060] Furthermore, in Figure 13, a configuration can also be adopted in which the center position of the reflective portion 30a coincides with the optical axis of the positive lens 51 and the fluorescence emission axis EA. In this case, the central axis of the hole 51b coincides with the optical axis of the positive lens 51. In addition, in the modified form of Figure 13, multiple holes 51b and a corresponding number of reflective portions 30a can be provided, and this configuration, like the embodiment described above, enables improved fluorescence output while saving space.

[0061] In the above embodiment, when a single reflective portion 30a is provided, a configuration can be adopted in which the center position of the reflective portion 30a coincides with the optical axis of the positive lens 51 or the fluorescence emission axis EA. Also, in the above embodiment, when multiple reflective portions 30a are provided, a configuration can be adopted in which the center position of any one of the reflective portions 30a coincides with the optical axis of the positive lens 51 or the fluorescence emission axis EA.

[0062] Although Figure 13 shows that the focusing lens 42 has a hole 42a, if the laser beam B emitted from the hole 51b efficiently hits the phosphor 41, then it is not necessary to provide a hole 42a in the focusing lens 42.

[0063] Furthermore, as shown in the other modified example in Figure 14, it is also possible to configure the system so that the laser beam B from the reflecting section 30a does not pass through the focusing optical system 50 but is directed towards the phosphor section 40. In the case of Figure 14, the laser beam B hits the phosphor 41 without passing through the focusing lens 42, but a configuration in which the laser beam B passes through the focusing lens 42 before hitting the phosphor 41 is also possible. In addition, in the case of Figure 14, the laser beam B is focused by the positive lens 46 before hitting the phosphor 41.

[0064] As described above, when the laser beam B strikes the phosphor 41, fluorescence is emitted radially from the phosphor 41, similar to the embodiment, and this fluorescence passes through the focusing lens 42 and the focusing optical system 50 in the second direction. In this modified example, the reflective section 30a is not located in the area where the fluorescence from the focusing optical system 50 travels. Furthermore, in this modified example, it is possible to provide multiple reflective sections 30a, and since the laser beam B is supplied to the phosphor 41 from each of the multiple reflective sections 30a, it is possible to improve the fluorescence output while saving space, similar to the embodiment.

[0065] In addition, in the modified example of Figure 14, it is also possible to provide the hole 42a shown in Figure 13 in the focusing lens 42, and to adopt a configuration in which the laser beam B strikes the phosphor 41 through the hole 42a. Alternatively, in the modified example of Figure 14, it is also possible to supply the laser beam B to the phosphor 41 through the focusing lens 42 without the hole 42a. Furthermore, in the modified example of Figure 14, it is also possible to configure the system so that the laser beam B that has passed through the density changing optical system 20 is directed toward the phosphor 41 without using the reflecting section 30a.

[0066] Furthermore, in the modified example shown in Figure 14, the phosphor 41 can be placed between the density changing optical system 20 and the focusing optical system 50 in the fluorescence emission direction. In this configuration, the laser beam B travels from the bottom to the top of the plane of Figure 14, and the laser beam B is reflected by the reflecting section 30a and directed toward the phosphor 41. In the above embodiment and each modified example, the phosphor section 40 may consist only of the phosphor 41.

[0067] In addition, in each of the above embodiments, the convex curved surface 51a or other lens surfaces may be made of Fresnel lenses, and in this case as well, each embodiment can achieve the above effects.

[0068] 1: Light source device, 10: First light source, 14: First light source reflector, 14a: Reflection region, 14b: Transmission region, 15: Second light source, 17: Second light source reflector, 20: Density changing optical system, 21: Positive lens section, 22: Negative lens section, 22a: Unidirectional concave lens, 22b: Concave lens, 30: Reflector, 30a: Reflector section, 31: Glass plate, 32: Laser light capturing section, 34: Glass plate, 40: Phosphor section, 41: Phosphor, 42: Focusing lens, 42a: Hole, 43: Disc, 44: Motor, 46: Positive lens, 50: Focusing optical system, 51: Positive lens, 51a: Convex curved surface, 51b: Hole, 60: Support member, 60a: First aperture, 60b: Second aperture, 61: First member, 61a: Surface, 62: Second member, 62a: Lens retainer, 63: Support surface, 70: Focusing lens, B: Laser beam, EA: Fluorescence emission axis, L: Laser light, LA: Light supply axis

Claims

1. A light source device comprising: a reflective section that reflects a laser beam having multiple laser beams; a phosphor section; and a focusing optical system disposed between the reflective section and the phosphor section, which allows the laser beam reflected by the reflective section to pass in a first direction toward the phosphor section, wherein the focusing optical system allows the fluorescence emitted radially from the phosphor section to pass in a second direction opposite to the first direction, and the area in which the reflective section is provided is 1 / 3 or less of the area of ​​the lens surface through which the fluorescence last passes in the second direction within the focusing optical system, viewed from the fluorescence emission direction, which is the direction in which the focusing optical system emits the fluorescence.

2. The light source device according to claim 1, wherein the reflective portion is arranged such that it is not located at the center of the lens surface when viewed from the direction of fluorescence emission.

3. The light source device according to claim 1, further comprising a support member for supporting at least one lens of the focusing optical system, wherein the support member cantileveredly supports the reflective member on which the reflective portion is provided.

4. The light source device according to claim 3, wherein the support member comprises a first member that contacts or is close to one surface in the thickness direction of the plate-shaped portion of the reflective member, and a second member that is fixed to the first member and contacts the other surface in the thickness direction of the plate-shaped portion.

5. The light source device according to claim 3 or 4, wherein the support member has a support surface that extends in the diagonal direction in order to position the reflective portion to extend in a direction diagonally with respect to the fluorescence emission direction.

6. A light source device according to any one of claims 1 to 4, further comprising: a light source that emits a plurality of laser beams; and a density changing optical system that narrows the distance between the plurality of laser beams from the light source to form the laser beam.

7. The light source device according to claim 5, further comprising: a light source that emits a plurality of laser beams; and a density changing optical system that narrows the distance between the plurality of laser beams from the light source to form the laser beam.

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