JP2012098442A - Wavelength conversion element, light source device, and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent body wheel, a light source device, and a projector that can inhibit reduction of light use efficiency as a whole system including the fluorescent body wheel.SOLUTION: A wavelength conversion element includes a wheel substrate 31, a fluorescent body layer 36 provided on the wheel substrate 31, and a first reflection part 34a provided on a first lateral surface 35a of a plurality of lateral surfaces that the fluorescent body layer 36 has, which first reflection part 34a reflects a light advancing parallel to the wheel substrate 31 in an inside of the fluorescent body layer 36 in a direction opposite to the wheel substrate 31.

Description

  The present invention relates to a wavelength conversion element, a light source device, and a projector, and more particularly to a phosphor wheel that generates fluorescence and can be suitably used for them.

  As one of light source devices used in a projector, a light source device that irradiates a phosphor with laser light as excitation light and generates fluorescence having a wavelength different from the excitation light has been proposed (see, for example, Patent Documents 1 and 2). ).

JP 2009-277516 A

  A phosphor layer of a conventional phosphor wheel that functions as a wavelength conversion element is provided in a wide range with respect to a spot that is an irradiation region of excitation light. The phosphor (phosphor crystal) dispersed in the phosphor layer emits the generated fluorescence isotropically. Since the phosphor layer has a predetermined thickness, the fluorescent component that makes a large angle with respect to the surface normal of the phosphor wheel substrate propagates outside the irradiation region of the excitation light in the phosphor layer. Become. Fluorescence propagated outside the irradiation region of the excitation light is further scattered by being incident on a phosphor existing ahead. When fluorescence propagates toward the outside of the irradiation region due to repeated scattering in the phosphor layer, the light emission area in the phosphor wheel increases. That is, etendue increases. The increase in the light emission area in the phosphor wheel increases the light that is not taken in by the optical system behind the light source device, and causes a reduction in the light utilization efficiency of the entire system including the phosphor wheel.

The light emitted from the phosphor layer exhibits an angular distribution close to Lambert radiation. The light emitted from the phosphor layer at a large angle with respect to the normal of the phosphor emitting surface of the phosphor layer is difficult to sufficiently capture by a pickup lens or a light guide provided on the emission side of the phosphor layer. As a result, the light utilization efficiency decreases.
An object of the present invention is to solve at least one of the above-described problems and provide a wavelength conversion element, a light source device, and a projector capable of improving the light utilization efficiency of the entire system including the wavelength conversion element. To do.

  The wavelength conversion element according to the present invention is provided on a first side surface among a plurality of side surfaces of the substrate, the phosphor layer provided on one surface of the substrate, and the phosphor layer, and the inside of the phosphor layer. And a first reflecting portion for reflecting light traveling in parallel with the one surface of the substrate in a direction opposite to the substrate.

According to such a configuration, the first reflecting portion reflects the light traveling in parallel with the one surface of the substrate inside the phosphor layer, thereby limiting the light emitting region and suppressing an increase in the light emitting area in the phosphor layer. Can be made. That is, the light emitting region does not extend beyond the first reflecting portion.
Further, the first reflecting unit can reflect light traveling in the phosphor layer in parallel with one surface of the substrate in a direction opposite to the substrate. That is, the light traveling direction can be changed so that the light ray angle with respect to the emission surface of the phosphor layer, that is, the surface normal of the interface between the phosphor layer and air becomes small. Thus, since the light ray angle on the emission surface of the phosphor layer becomes small, total reflection of light on the emission surface of the phosphor layer is suppressed. In addition, since the emission angle of light emitted from the phosphor layer is reduced, the amount of light taken in by the pickup lens and the light guide means is increased. Thereby, the fall of the light utilization efficiency as the whole system containing a wavelength conversion element can be suppressed.

  Moreover, as a preferable aspect of the wavelength conversion element described above, the first side surface is either one of a direction along a circle centering on the rotation axis of the substrate and a direction intersecting the circle. Desirably along the direction.

  When the first side surface is along a direction along a circle centered on the rotation axis of the substrate, an increase in the light emitting area is suppressed in the radial direction of the circle, and the light ray angle of light emitted from the phosphor layer is set. Can be small. Further, when the first side surface is along a direction intersecting with a circle centering on the rotation axis of the substrate, the light emitted from the phosphor layer is suppressed while suppressing an increase in the light emitting area in the circumferential direction of the circle. The light beam angle can be reduced.

  Moreover, as a preferable aspect of the wavelength conversion element described above, the wavelength conversion element is provided on the second side surface of the phosphor layer facing the first side surface, and proceeds inside the phosphor layer in parallel with the substrate. It is desirable to further have a second reflecting portion that reflects light in a direction opposite to the substrate.

  Thereby, the increase in the light emission area can be further suppressed. Furthermore, since the amount of light emitted from the phosphor layer at a small light beam angle can be increased, the amount of light taken in by the pickup lens or the light guide means can be further increased.

  In addition, as a preferable aspect of the wavelength conversion element described above, the wavelength conversion element is provided on a third side surface of the phosphor layer intersecting with the first side surface, and proceeds inside the phosphor layer in parallel with the substrate. A third reflecting portion configured to reflect light in a direction opposite to the substrate; and a fourth side surface of the phosphor layer facing the third side surface, wherein the interior of the phosphor layer is disposed on the substrate. It is desirable to further include a fourth reflecting portion that reflects light traveling in parallel to the substrate in a direction opposite to the substrate.

  As a result, when the phosphor layer is irradiated with excitation light while rotating the wavelength conversion element around a predetermined rotation axis, the light emitting region is limited in both the radial direction and the circumferential direction of the circle around the rotation axis. Therefore, an increase in the light emission area can be further suppressed. In addition, the amount of light taken in by the pickup lens or the light guide means can be further increased.

  Moreover, as a preferable aspect of the wavelength conversion element described above, it is desirable that the phosphor layer is provided on the surface of the substrate.

  By providing the phosphor layer on the substrate, the heat generated in the phosphor layer can be effectively dissipated to the outside.

  As a preferred embodiment of the wavelength conversion element described above, it is desirable that the phosphor layer is provided in a groove provided in the substrate.

  By providing the phosphor layer in the groove of the substrate, the material of the phosphor layer can be stably applied.

  Moreover, as a preferable aspect of the wavelength conversion element described above, it is desirable to further include a heat conduction member provided on the opposite side of the phosphor layer of the first reflecting portion.

  Thereby, the heat generated in the phosphor layer can be effectively dissipated.

  Moreover, as a preferable aspect of the wavelength conversion element described above, a fluorescence that is provided between the substrate and the phosphor layer, transmits excitation light that excites the phosphor, and is emitted from the phosphor. It is desirable to have a wavelength separation layer that reflects light.

  The wavelength separation layer reflects the fluorescence traveling toward the incident surface of the excitation light through the phosphor layer. Thereby, when the excitation light is irradiated from the side opposite to the surface on which the phosphor layer of the substrate is provided, the wavelength conversion element can efficiently emit fluorescence.

  Moreover, as a preferable aspect of the wavelength conversion element described above, it is provided between the substrate and the phosphor layer, and reflects excitation light that excites the phosphor and fluorescence emitted from the phosphor. It is desirable to have a reflective layer.

  Thereby, when the phosphor is irradiated with the excitation light from the side opposite to the substrate, the wavelength conversion element can efficiently emit the fluorescence and a part of the excitation light.

  Furthermore, a light source device according to the present invention includes an excitation light source unit that emits excitation light, and the wavelength conversion element that emits fluorescence when irradiated with the excitation light.

  Accordingly, it is possible to provide a light source device that has high light use efficiency as a whole system including the light source device and can obtain desired color light.

  In a preferred embodiment of the light source device described above, the spot diameter of the excitation light formed on the wavelength conversion element is such that the phosphor layer in the radial direction of a circle centering on the rotation axis of the substrate is Desirably smaller than the width.

  Accordingly, it is possible to increase an allowable range of shaking due to the rotation of the wavelength conversion element so that the incident position of the excitation light does not protrude from the phosphor layer.

  Furthermore, a projector according to the present invention is characterized in that the light emitted from the light source device is modulated in accordance with an image signal and projected.

  Thereby, the projector can suppress the fall of the light utilization efficiency as the whole system.

FIG. 1 is a schematic configuration diagram of a projector according to a first embodiment of the invention. FIG. 2 is a diagram showing the configuration of the phosphor wheel. FIG. 3 is a cross-sectional view of the phosphor wheel. FIG. 4 is a cross-sectional view of a main part of the phosphor wheel according to the first modification of the first embodiment. FIG. 5 is a cross-sectional view of a main part of the phosphor wheel according to the second modification of the first embodiment. FIG. 6 is a schematic configuration diagram of a projector according to the second embodiment of the invention. FIG. 7 is a plan view of the phosphor wheel. FIG. 8 is a cross-sectional view of a main part of the phosphor wheel. FIG. 9 is a cross-sectional view of a main part of the phosphor wheel. FIG. 10 is a plan view of the filter. FIG. 11 is a cross-sectional view of a main part of the phosphor wheel according to the third embodiment of the present invention. FIG. 12 is a diagram illustrating an illumination apparatus according to Embodiment 3 of the present invention.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a projector 1 according to a first embodiment of the invention. The light source device 10 emits illumination light including red (R) light, green (G) light, and blue (B) light. The light source device 10 includes a laser diode array 2, a condenser lens 4, a phosphor wheel 100 that functions as a wavelength conversion element, and a pickup lens 6.

The laser diode array 2 is composed of a plurality of laser diodes 3 arranged in an array. The laser diode array 2 functions as a pumping light source unit that emits the pumping light 60. The excitation light 60 is, for example, B light having a wavelength near 450 nm. The condensing lens 4 functions as a condensing optical system that condenses the excitation light 60 emitted from the laser diode array 2 in the phosphor wheel 100.
The phosphor wheel 100 emits fluorescence having a wavelength different from that of the excitation light 60 when the excitation light 60 is irradiated. The pickup lens 6 is provided on the optical path of the excitation light 60. The pickup lens 6 captures the fluorescence emitted from the phosphor wheel 100 and the excitation light 60 transmitted through the phosphor wheel 100 and advances it to the collimating optical system 11.

  The collimating optical system 11 condenses the light from the light source device 10 on the rod integrator 12. The rod integrator 12 multi-reflects the incident light internally to make it uniform, and emits the uniformed light toward the superimposing lens 13. The superimposing lens 13 superimposes the light beam divided into a plurality by the rod integrator 12 using a spatial light modulator.

  The first dichroic mirror 14 reflects R light and G light incident from the superimposing lens 13 and transmits B light. The B light transmitted through the first dichroic mirror 14 has its optical path bent by reflection by the reflection mirror 16 and is incident on the incident-side polarizing plate 20B. The light transmitted through the incident side polarizing plate 20B enters the liquid crystal panel 21B. The liquid crystal panel 21B constitutes a spatial light modulation device that modulates the B light according to the image signal. The light transmitted through the liquid crystal panel 21B is incident on the exit-side polarizing plate 22B. The B light transmitted through the exit side polarizing plate 22B enters the cross dichroic prism 23.

  The R light and G light reflected by the first dichroic mirror 14 enter the second dichroic mirror 15. The second dichroic mirror 15 reflects G light and transmits R light. The G light whose optical path is bent by the reflection at the second dichroic mirror 15 enters the incident-side polarizing plate 20G. The G light transmitted through the incident side polarizing plate 20G is incident on the liquid crystal panel 21G. The liquid crystal panel 21G constitutes a spatial light modulation device that modulates G light according to an image signal. The light transmitted through the liquid crystal panel 21G is incident on the exit-side polarizing plate 22G. The G light transmitted through the exit-side polarizing plate 22G enters the cross dichroic prism 23.

  The R light that has passed through the second dichroic mirror 15 has its optical path bent by reflection by the reflection mirror 17 and enters the relay lens 18. The R light that has passed through the relay lens 18 has its optical path bent due to reflection by the reflection mirror 19, and is incident on the incident-side polarizing plate 20R. The R light transmitted through the incident side polarizing plate 20R enters the liquid crystal panel 21R. The liquid crystal panel 21R constitutes a spatial light modulation device that modulates R light according to an image signal. The light transmitted through the liquid crystal panel 21R is incident on the exit-side polarizing plate 22R. The R light transmitted through the exit side polarizing plate 22R enters the cross dichroic prism 23.

  The cross dichroic prism 23 that is a color combining optical system combines the light modulated by each spatial light modulation device into image light, and advances it to the projection optical system 24. The projection optical system 24 projects the image light combined by the cross dichroic prism 23 onto a screen (not shown).

FIG. 2A is a plan view of the phosphor wheel 100 that functions as a wavelength conversion element, and is a plan view of the phosphor wheel 100 as viewed from the side where the structure 32 is provided. FIG. 2B is a cross-sectional view of the phosphor wheel 100 and includes a center position of the phosphor wheel 100. 2 (a) and 2 (b), the wheel motor 33 is mounted on the phosphor wheel 100, and in FIG. 2 (b), the pickup lens 6 is further combined with the phosphor wheel 100. .
FIG. 3 is a cross-sectional view taken along the line AA ′ in the radial direction of the circle centering on the rotation axis R of the phosphor wheel 100 in FIG.

  The phosphor wheel 100 includes a wheel substrate 31 that can rotate around a rotation axis R and a structure 32.

  As shown in FIG. 2, the wheel substrate 31 is a circular plate-like member, and is made of a transparent member such as glass. In the center of the wheel substrate 31, an opening through which the columnar wheel motor 33 passes is provided. The wheel substrate 31 is integrated with the wheel motor 33 by mounting the wheel substrate 31 to the wheel motor 33 at the opening. The wheel substrate 31 rotates with the center position of the circular shape as the rotation axis R by driving the wheel motor 33.

  As shown in FIG. 3, in this embodiment, the structural body 32 includes a phosphor layer 36, a first reflecting portion 34a, and a second reflecting portion 34b. The phosphor layer 36 includes a plurality of particulate phosphors 1000. The excitation light 60 enters the phosphor layer 36 from the incident surface 36a side of the phosphor layer 36 and excites the phosphor 1000. The excited phosphor 1000 generates fluorescence. The fluorescence emitted from the phosphor 1000 and a part of the excitation light 60 transmitted through the phosphor layer 36 are emitted from the emission surface 36 b of the phosphor layer 36. In the present specification, the emission surface 36b refers to a surface from which a fluorescence emitted from the phosphor 1000 is emitted from the phosphor layer 36 into the air among a plurality of surfaces of the phosphor layer 36.

A recess 37 is provided on one surface of the wheel substrate 31, that is, the surface 31 a of the wheel substrate 31 opposite to the surface 31 b on which the excitation light 60 is incident on the wheel substrate 31, and the structure 32 is disposed in the recess 37. Is provided. The emission surface 36b of the phosphor layer 36 and the surface 31a of the wheel substrate 31 are continuous with each other.
As shown in FIG. 2A, the structure 32 including the phosphor layer 36 forms a ring having a certain width in plan view. The ring formed by the phosphor layer 36 (structure 32) corresponds to the locus of the irradiation region of the excitation light 60 obtained by rotating the wheel substrate 31 around the rotation axis R.

  In FIG. 3, the phosphor layer 36 includes a first side surface 35a and a second side surface 35b. The first side surface 35a and the second side surface 35b have a circular shape centered on the rotation axis R in plan view, and face each other. The first side surface 35 a is the side surface of the annular phosphor layer 36 on the wheel motor 33 side, and the second side surface 35 b is the side surface of the annular phosphor layer 36 on the outer edge side of the wheel substrate 31. In the present embodiment, the first side surface 35a and the second side surface 35b may be collectively referred to as the side surface 35 as appropriate.

  The first reflecting portion 34 a is provided on the first side surface 35 a of the phosphor layer 36, and the second reflecting portion 34 b is provided on the second side surface 35 b of the phosphor layer 36. In a cross section intersecting the first side surface 35a, for example, a cross section AA ′ along the radial direction of a circle centering on the rotation axis R, the distance between the first side surface 35a and the second side surface 35b is: The excitation light 60 increases from the incident surface 36a toward the fluorescence exit surface 36b. Therefore, the distance between the first reflection part 34a and the second reflection part 34b is also increased from the incident surface 36a of the excitation light 60 toward the fluorescence emission surface 36b.

  In the present embodiment, the first reflecting portion 34a and the second reflecting portion 34b may be collectively referred to as the reflecting portion 34 as appropriate. In addition, in this specification, for convenience, the reflecting portion 34 provided in the above-described form is referred to as a tapered reflecting portion 34. Or it says that the reflection part 34 has a taper shape. The reflector 34 reflects the fluorescence and excitation light 60 emitted from the phosphor layer 36. As the reflection part 34, a highly reflective member, for example, a film made of a metal member is used.

  The dichroic film 38 is provided on the incident surface 36a between the wheel substrate 31 and the phosphor layer 36, and has a circular shape centering on the rotation axis R in plan view. The dichroic film 38 functions as a wavelength separation layer having a wavelength characteristic that transmits the excitation light 60 emitted from the laser diode array 2 and reflects the fluorescence emitted from the phosphor 1000.

The phosphor 1000 generates fluorescence including G light and R light when irradiated with the excitation light 60. A part of the excitation light 60 incident on the phosphor layer 36 is emitted from the emission surface 36b of the phosphor layer 36 toward the pickup lens 6 together with the fluorescence. As described above, the light source device 10 emits white illumination light by mixing the fluorescence including the G light and the R light and the excitation light 60 including the B light.
For example, a YAG phosphor is used as the phosphor. The phosphor layer 36 is obtained, for example, by applying a powdered phosphor 1000 and a binder to the wheel substrate 31 and thermally curing the mixture.

  A spot of excitation light 60 is formed on the incident surface 36 a of the phosphor layer 36. The light source device 10 is adjusted such that the spot diameter d1 of the excitation light 60 along the radial direction of the circle centered on the rotation axis R is smaller than the width M of the incident surface 36a. Accordingly, it is possible to increase an allowable range of shake due to rotation of the wavelength conversion element so that the incident position of the excitation light 60 does not protrude from the incident surface 36a.

  The excitation light 60 incident on the wheel substrate 31 passes through the wheel substrate 31 and the dichroic film 38 and enters the phosphor layer 36. A part of the excitation light 60 incident on the phosphor layer 36 excites the phosphor 1000, and the excited phosphor 1000 emits fluorescence. The fluorescence generated in the phosphor 1000 is emitted approximately isotropic around the light emission position.

Light that travels inside the phosphor layer 36 in parallel with the surface 31a of the wheel substrate 31 or at a large angle with respect to the normal line N of the emission surface 36b of the phosphor layer 36 is reflected by the reflector 34. . Therefore, the propagation of fluorescence in the radial direction of the circle centered on the rotation axis R is limited, and the light emitting region is limited to the region between the first reflecting portion 34a and the second reflecting portion 34b. That is, the light emitting region does not extend beyond the first reflecting portion 34a. Further, the light emitting area does not extend beyond the second reflecting portion 34b. Therefore, an increase in the light emission area can be suppressed.

The fluorescence that has traveled inside the phosphor layer 36 toward the incident surface 36 a side of the wheel substrate 31 is reflected by the dichroic film 38 and proceeds in the direction of the exit surface 36 b of the phosphor layer 36. Therefore, the fluorescence emitted from the phosphor 1000 does not leak to the incident surface 36 a side of the wheel substrate 31 and can be efficiently emitted from the emission surface 36 b of the phosphor layer 36.
In addition, among the excitation light 60 transmitted through the phosphor layer 36 and the fluorescence emitted by the phosphor 1000, the component incident at an angle smaller than the critical angle with respect to the emission surface 36b of the phosphor layer 36 is phosphor. Injection from the layer 36 into the air.

By reflecting light in a direction opposite to the incident surface 36a side of the wheel substrate 31 by the tapered reflecting portion 34, the traveling direction of the light is changed so that the light ray angle with respect to the normal line N of the exit surface 36b becomes small. Can do. Therefore, the light ray angle at the exit surface 36b of the phosphor layer 36 is reduced, the total reflection of light at the exit surface 36b is suppressed, and the light traveling inside the phosphor layer 36 is air from the exit surface 36b of the phosphor layer 36. It becomes easy to inject.
Since the amount of light reflected by the emission surface 36b of the phosphor layer 36 and returning to the phosphor layer 36 is reduced, light loss and heat generation due to absorption of the fluorescence by the phosphor layer 36 are caused. It is suppressed.

Further, by reducing the emission angle (light ray angle) of the light emitted from the emission surface 36b of the phosphor layer 36, the amount of light taken in by the pickup lens 6 and the like can be increased.
Thus, the light use efficiency of the entire system of the projector 1 including the phosphor wheel 100 can be improved.

(Modification 1)
FIG. 4 is a cross-sectional view of the main part of the phosphor wheel according to the first modification of the present embodiment, and corresponds to the cross-sectional view of FIG. In the phosphor wheel 100 according to the first embodiment, the emission surface 36b of the phosphor layer 36 and the surface 31a of the wheel substrate 31 are provided to be continuous with each other. However, in the phosphor wheel 200 according to the present modification, The emission surface 36 b of the phosphor layer 36 is embedded in a recess 37 provided in the wheel substrate 31.

  The reflector 34 is sandwiched between the side surface 35 of the phosphor layer 36 and the wall surface of the recess 37. Further, the reflecting portion 34 is not provided only on the side surface 35 of the phosphor layer 36, but extends from the emission surface 36 b of the phosphor layer 36 to the vicinity of the surface 31 a of the wheel substrate 31 along the wall surface of the recess 37. Exist. In the present modification, the reflecting portion 34 extends from the emission surface 36 b of the phosphor layer 36 to the surface 31 a of the wheel substrate 31.

  According to the phosphor wheel 200 according to this modification, the following effects can be obtained in addition to the effects obtained in the phosphor wheel 100 according to the first embodiment.

  Of the light emitted from the emission surface 36 b of the phosphor layer 36, the light emitted at a large angle with respect to the normal line N is reflected by the reflecting portion 34 in the direction of the pickup lens 6. The amount of can be increased. Thereby, the light utilization efficiency as the whole system of the projector 1 including the phosphor wheel 200 can be further improved.

(Modification 2)
FIG. 5 is a cross-sectional view of the main part of the phosphor wheel according to the second modification of the present embodiment, and corresponds to the cross-sectional view of FIG. In the phosphor wheel 100 according to the first embodiment, the structure 32 is embedded in the concave portion 37 provided in the wheel substrate 31. However, in the phosphor wheel 300 according to the second modification, the structure 32 is formed on the wheel substrate 31. It is provided on the surface 31a.
According to the phosphor wheel 300 according to the present modification, in addition to the effects obtained in the phosphor wheel 100 according to the first embodiment, heat generated in the phosphor layer 36 can be effectively dissipated to the outside. An effect is also obtained.

(Modification 3)
In the phosphor wheel according to the first embodiment and the first and second modifications, the first reflecting portion 34a and the second reflecting portion 34b are provided, but only one of them may be provided. For example, when only the second reflecting portion 34b is provided, the fluorescent component that travels at a large angle with respect to the normal line N of the emission surface 36b of the phosphor layer 36 is reflected by the second reflecting portion 34b. Propagation in the outer direction of the wheel substrate 31 is limited. The light reflected by the second reflecting portion 34b travels while being scattered by the phosphor 1000 inside the phosphor layer 36, and eventually emerges from the exit surface 36b into the air. Therefore, even when only one of the first reflecting portion 34a and the second reflecting portion 34b is provided, the effect of improving the light utilization efficiency of the entire system can be obtained.

  A projector according to the second embodiment will be described with reference to FIGS. FIG. 6 is a schematic configuration diagram of a projector 600 according to the second embodiment of the invention. FIG. 7 is a plan view of the phosphor wheel 400. FIG. 8 is a view showing a cross section C-C ′ of the phosphor wheel 400, and FIG. 9 is a view showing a cross section B-B ′ of the phosphor wheel 400. FIG. 10 is a plan view of the filter 620.

  In the first embodiment, one annular structure 32 is provided on the wheel substrate 31, but in the phosphor wheel 400 according to the present embodiment, as shown in FIG. 7, a plurality of structures 32R and a plurality of structures 32R are provided. The structure 32 </ b> G is annularly arranged so as to surround the rotation axis R of the wheel substrate 31. Further, an opening 433 through which the columnar wheel motor 33 passes is provided. The structure 32R includes a phosphor layer 36R including a phosphor 1000R that emits red fluorescence when excited by the excitation light 60, and the structure 32G emits green fluorescence when excited by the excitation light 60. A phosphor layer 36G including the phosphor 1000G is provided. The excitation light 60 is blue light having a wavelength near 450 nm, as in the first embodiment.

  The structure 32R will be described with reference to FIGS. Since the structure 32G has the same structure as the structure 32R, the description of the structure 32G is omitted. The structure 32R includes a phosphor layer 36R, a first reflection part 34a, a second reflection part 34b, a third reflection part 84a, and a fourth reflection part 84b. In the phosphor layer 36R, particulate phosphor 1000R is dispersed. The excitation light 60 enters the phosphor layer 36R from the incident surface 36a side of the phosphor layer 36R, and excites the phosphor 1000R. The excited phosphor 1000R emits red fluorescence. A part of the excitation light 60 transmitted through the phosphor layer 36R and the fluorescence emitted by the phosphor 1000R are emitted from the emission surface 36b of the phosphor layer 36R.

  As shown in FIG. 8, the phosphor layer 36R includes a first side surface 35a and a second side surface 35b. The first side surface 35a and the second side surface 35b have a circular shape centering on the rotation axis R of the wheel substrate 31 in plan view, and face each other in the radial direction of the circle. The first side surface 35 a is a side surface of the phosphor layer 36 on the wheel motor 33 side, and the second side surface 35 b is a side surface of the phosphor layer 36 on the outer edge side of the wheel substrate 31. The first reflecting portion 34a is provided on the first side surface 35a of the phosphor layer 36R, and the second reflecting portion 34b is provided on the second side surface 35b of the phosphor layer 36R. Similar to the phosphor wheel 100 according to the first embodiment, in a cross section intersecting the first side face 35a, for example, a cross section CC ′ along a radial direction of a circle centering on the rotation axis R, the first side face 35a and the first side face 35a. The distance between the two side surfaces 35b increases from the incident surface 36a toward the exit surface 36b. Accordingly, the distance between the first reflecting portion 34a and the second reflecting portion 34b is also increased from the incident surface 36a toward the exit surface 36b.

  As shown in FIG. 9, the phosphor layer 36 </ b> R further includes a third side surface 85 a and a fourth side surface 85 b that extend in the radial direction of a circle centered on the rotation axis R of the wheel substrate 31. The third side surface 85a and the fourth side surface 85b face each other in the circumferential direction of the circle. The third reflecting portion 84a is provided on the third side surface 85a of the phosphor layer 36R, and the fourth reflecting portion 84b is provided on the fourth side surface 85b of the phosphor layer 36R. In a cross section intersecting the third side surface 85a, for example, a cross section BB ′ along the circumferential direction of the circle having the rotation axis R as the center, the distance between the third side surface 85a and the fourth side surface 85b is , And increases from the incident surface 36a toward the exit surface 36b. Accordingly, the distance between the third reflecting portion 84a and the fourth reflecting portion 84b also increases from the incident surface 36a toward the exit surface 36b.

  In the present embodiment, the first side surface 35a and the second side surface 35b may be collectively referred to as the side surface 35, and the third side surface 85a and the fourth side surface 85b may be collectively referred to as the side surface 85 as appropriate. In addition, the first reflecting portion 34a and the second reflecting portion 34b may be collectively referred to as the reflecting portion 34, and the third reflecting portion 84a and the fourth reflecting portion 84b may be collectively referred to as the reflecting portion 84 as appropriate. . Further, as in the first embodiment, the reflecting portion 34 and the reflecting portion 84 provided in the above-described form are referred to as a tapered reflecting portion. Or it says that the reflective part has a taper shape. Since the reflecting portion 34 and the reflecting portion 84 have a tapered shape, the fluorescence and excitation light 60 incident from the phosphor layer 36R are reflected toward the exit surface 36b. As the reflection part 34 and the reflection part 84, a highly reflective member, for example, a film made of a metal member is used.

  As illustrated in FIG. 7, a region 424 in which no phosphor is provided is provided between the pair of structures 32 </ b> R and 32 </ b> G and the other pair of structures 32 </ b> R and 32 </ b> G. The pair of structures 32 </ b> R, the structures 32 </ b> G, and the regions 424 where the phosphors are not provided are alternately provided in the circumferential direction of a circle centering on the rotation axis R of the wheel substrate 31. The excitation light 60 can pass through the region 424 where no phosphor is provided. Therefore, with the rotation of the wheel substrate 31, the wheel substrate 31 emits light in which blue excitation light and red fluorescence are mixed, light in which blue excitation light and green fluorescence are mixed, and blue excitation. Light is emitted sequentially.

Next, a projector 600 using the phosphor wheel 400 will be described with reference to FIG. Explanation of members common to the projector 1 according to the first embodiment is omitted.
The light source device 610 includes a laser diode array 2, a condenser lens 4, a phosphor wheel 400, a filter 620, and a pickup lens 6.

  As shown in FIG. 10, the filter 620 reflects the excitation light 60 incident from the phosphor wheel 400 side and transmits the red fluorescence and the green fluorescence emitted from the phosphor wheel 400. Are provided. Further, a region 624 where the dichroic film 622 is not provided is provided between two adjacent dichroic films 622. The region 624 where the dichroic film 622 is not provided and the region where the dichroic film 622 is provided are alternately provided in the circumferential direction of a circle around the rotation axis R of the filter 620. The excitation light 60 can pass through the region 624 where the dichroic film 622 is not provided. Further, the region 624 where the dichroic film 622 is not provided is subjected to a process for diffusing the excitation light 60. For example, in the region 624 where the dichroic film 622 is not provided, the excitation light 60 can be diffused by making the surface of the filter 620 rough.

  The filter 620 is also provided with an opening 633 through which the columnar wheel motor 33 passes. In the filter 620 and the phosphor wheel 400, the dichroic film 622 provided on the filter 620 overlaps the pair of structures 32R and 32G provided on the phosphor wheel 400 in plan view, and the dichroic film of the filter 620 The wheel motor 33 is mounted so that the region 624 where the 622 is not provided overlaps with the region 424 where the phosphor of the phosphor wheel 400 is not provided in plan view. By attaching the filter 620 and the phosphor wheel 400 to the wheel motor 33 as described above, red light, blue light, and green light are emitted from the light source device 610 as illumination light as the filter 620 and the phosphor wheel 400 rotate. Are fired sequentially.

  The illumination light emitted from the light source device 610 passes through other members and enters the mirror device 630. As the mirror device 630, for example, a DMD (digital micromirror device) element manufactured by Texas Instruments Inc. can be used. Each color light incident on the mirror device 630 as illumination light is modulated by the mirror device 630. The modulated light enters the prism 650, is reflected by the mirror surface in the prism 650, and enters the reflecting plate 651. The light incident on the reflection plate 651 is reflected toward the projection optical system 24. The light reflected in the direction of the projection optical system 24 is enlarged and projected on a screen (not shown) by the projection optical system 24. In this way, a red image, a blue image, and a green image are sequentially projected on the screen, and a color image is displayed.

  The phosphor wheel 400 limits the light emitting region in both the circumferential direction and the radial direction by providing the reflective portion 34 having a tapered shape in the circumferential direction and providing the reflective portion 84 having a tapered shape in the radial direction. , The increase in the light emitting area can be suppressed. Furthermore, the light ray angle with respect to the normal line of the exit surface 36b can be reduced on the exit surface 36b. Thereby, the light utilization efficiency as the whole system of the projector 600 including the phosphor wheel 400 can be further increased.

  FIG. 11 is a cross-sectional view of a main part of a phosphor wheel 700 that functions as a wavelength conversion element according to Example 3 of the invention. Differences from the phosphor wheel 100 according to the first embodiment will be described. In the phosphor wheel 700 according to the present embodiment, a reflection layer 72 that reflects the excitation light 60 and the fluorescence is provided on the incident surface 36 a of the phosphor layer 36 instead of the dichroic film 38.

  The excitation light 60 is irradiated to the phosphor 1000 (not shown) from the side where the structure 32 of the wheel substrate 31 is provided, and the phosphor 1000 emits fluorescence. The fluorescence that has traveled toward the wheel substrate 31 in the phosphor layer 36 is reflected by the reflective layer 72. Therefore, the fluorescence emitted from the phosphor 1000 can be efficiently emitted from the emission surface 36b of the phosphor layer 36 without leaking to the wheel substrate 31 side. Similarly, the excitation light 60 traveling inside the phosphor layer 36 toward the wheel substrate 31 is similarly reflected by the reflection layer 72 and can be efficiently emitted from the emission surface 36 b of the phosphor layer 36.

  FIG. 12 shows a light source device 710 using a phosphor wheel 700. The excitation light 60 is applied to the phosphor 1000 from the side of the wheel substrate 31 where the structure 32 is provided, and a part of the excitation light 60 and the fluorescence emitted by the phosphor 1000 are captured by the pickup lens 6. The The light captured by the pickup lens 6 proceeds to the collimating optical system 11 described in the first embodiment. In this way, the light source device 710 is used as a light source for the projector. Even with such a reflective wheel substrate 31, as in the transmissive wheel substrate 31 described in the first embodiment, the effect of improving the light utilization efficiency of the entire system can be obtained.

  In the case of the reflective phosphor wheel 700, it is not necessary to use a transparent member as the wheel substrate 31. If a metal is used as the wheel substrate 31, heat generated in the phosphor 1000 can be effectively dissipated. In this case, as shown in Example 1 and Modification 1, it is preferable to provide the phosphor layer 36 in the groove provided on the surface of the wheel substrate. According to this configuration, the heat generated in the phosphor 1000 can be dissipated more efficiently. Further, if a metal having a high light reflectance such as aluminum is used, the wheel substrate itself functions as the reflecting portion 34, the reflecting portion 84, and the reflecting layer 72, so that it is not necessary to provide the reflecting portion 34 and the reflecting layer 72 separately.

  The phosphor wheel 31 of each embodiment is not limited to being applied to the projector 1 that uses a transmissive liquid crystal panel as a spatial light modulator or the projector 600 that uses a mirror device as a spatial light modulator. The phosphor wheel may be applied to a projector including a reflective LCOS (Liquid Crystal On Silicon).

  As described above, the phosphor wheel, the light source device, and the projector according to the present invention are useful when displaying an image using laser light.

  DESCRIPTION OF SYMBOLS 1,600 ... Projector, 2 ... Laser diode array, 3 ... Laser diode, 4 ... Condensing lens, 6 ... Pick-up lens, 10, 610, 710 ... Light source device, 11 ... Collimating optical system, 12 ... Rod integrator, 13 ... Superimposing lens, 14 ... first dichroic mirror, 15 ... second dichroic mirror, 16, 17, 19 ... reflection mirror, 18 ... relay lens, 20B, 20G, 20R ... incident side polarizing plate, 21R, 21G, 21B ... liquid crystal panel 22R, 22G, 22B ... Ejection side polarizing plate, 23 ... Cross dichroic prism, 24 ... Projection optical system, 31 ... Wheel substrate, 31a ... Surface, 31b ... Surface on which excitation light is incident, 32,32G, 32R ... Structure 33 ... wheel motor, 34a ... first reflecting part, 34b ... second reflecting part, 5a ... first side surface, 35b ... second side surface, 36 ... phosphor layer, 36a ... incident surface, 36b ... exit surface, 37 ... concave, 38,622 ... dichroic film, 60 ... excitation light, 72 ... reflection layer , 84a... Third reflecting portion, 84b... Fourth reflecting portion, 85a... Third side surface, 85b... Fourth side surface, 100, 200, 300, 400, 700. Area not provided, 433, 633 ... opening, 620 ... filter, 624 ... area without dichroic film, 630 ... mirror device, 650 ... prism, 651 ... reflector, 1000 ... phosphor, R ... rotation axis .

Claims (12)

A substrate,
A phosphor layer provided on one surface of the substrate;
A first light source is provided on a first side surface of the plurality of side surfaces of the phosphor layer and reflects light traveling in the phosphor layer in parallel with the one surface of the substrate in a direction opposite to the substrate. The reflective part of
A wavelength conversion element comprising:   2. The first side surface according to claim 1, wherein the first side surface is along one of a direction along a circle centering on a rotation axis of the substrate and a direction intersecting with the circle. Wavelength conversion element.   A second side surface provided on the second side surface of the phosphor layer facing the first side surface, and reflects light traveling in the phosphor layer in parallel with the substrate in a direction opposite to the substrate. The wavelength conversion element according to claim 2, further comprising a reflection portion. A third side surface provided on a third side surface of the phosphor layer that intersects the first side surface and reflects light traveling in the phosphor layer in parallel with the substrate in a direction opposite to the substrate; A reflection part;
A fourth side surface provided on a fourth side surface of the phosphor layer facing the third side surface, and reflects light traveling in the phosphor layer in parallel with the substrate in a direction opposite to the substrate. A reflection part;
The wavelength conversion element according to claim 2, further comprising:   The wavelength conversion element according to any one of claims 1 to 4, wherein the phosphor layer is provided on a surface of the substrate.   The wavelength conversion element according to claim 1, wherein the phosphor layer is provided in a groove provided in the substrate.   The wavelength conversion element according to claim 1, further comprising a heat conductive member provided on the opposite side of the first reflecting portion from the phosphor layer.   2. A wavelength separation layer that is provided between the substrate and the phosphor layer, transmits excitation light that excites the phosphor, and reflects fluorescence emitted from the phosphor. The wavelength conversion element as described in any one of 7 to 7.   The reflective layer which is provided between the said board | substrate and the said fluorescent substance layer, and reflects the excitation light which excites the said fluorescent substance, and the fluorescence inject | emitted from the said fluorescent substance is characterized by the above-mentioned. The wavelength conversion element as described in any one. An excitation light source unit that emits excitation light;
10. A light source device comprising: the wavelength conversion element according to claim 1, wherein fluorescence is emitted by irradiation of the excitation light.   11. The light source according to claim 10, wherein a spot diameter of the excitation light formed on the wavelength conversion element is smaller than a width of the phosphor layer in a radial direction of a circle centering on a rotation axis of the substrate. apparatus.   The projector which modulates the light inject | emitted from the light source device of Claim 10 or 11 according to an image signal, and projects it.

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